Jomida Vol-1 Issue-3 May 2013

Oral Cancer An update

Strenocleidomastoid myocutaneous flap in the reconstruction of mandibular defect

Flexible Denture For partially edentulous mouth -A review

Early vs late treatment for class-2 mal occlusionA systematic review concerning orthodontic treatment efficiency

Minimally Invasive Prosthodontics A review

3D Dimension diagnostic aid -CBCTIN Orthodontics

Porcelain Laminates- a problem based treatment approach

Gene therapy in oral diseases -An over view

Keratocystic Odontogenic Tumor Of the mandibleA case report

Minimal Invasive Dentistry -A new perspective

Prosthodontic considerations in periodontally compromised dentition A systematic approachPublic Recognition of Our Speciality A study

Antioxidants and it’s role in Oral Cancer - A review

01Vol-1 issue-3 june-2013

President:Dr.G.Sathish Kumar

Imm.Past President: Dr.S.KarthigaKannan

President-Elect:Dr. J.D. Dias

Vice Presidents:Dr.SelvaLibin ,Dr.Indra Kumar

Hon. Branch Secretary:Dr.Subramonian.S

Hon. Jt. Secretary: Dr.Sherin LeonHon. Asst. Secretary:Dr.Sudha Rani

Hon. Treasurer: Dr.LeonDuraiRep to C.D.E:Dr.Farakath Khan

Rep to C.D.H:Dr.Beyanso.C.P.Daniel

Rep to State: Dr.J.D.Dias ,Dr.Subramonian ,Dr. V. Manoj

Executive Committee: Dr.SankarPandian ,Dr.JeslinBeyanso Dr. Harry NihilNayagam

Journal Editor: Dr.R.Sambhu

Journal Co-Editor:Dr. Krishna Prasad

Website & Event:Dr. Merlin Raja Singh ,Dr.Jithin.G.Nelson

Greeting Committee :Dr. Shine Manoj.D.J

Student Membership:Dr.Anuroopa

Membership Committee:Dr.Priya.M.S ,Dr.Manoj.J.R ,Dr.Dhano

Legal Cell:Adv.Rtn. Mohanan Nair ,Dr. B. Krishna Prasad

Advisory Committee: Dr.J.D.Dias ,Dr.M.IrwinAnand ,Dr.AnithaJeslin Dr.Jain.R.S

Care and Concern:Dr.Selva Kumar

IDA -MARTHANDAM BRANCH OFFICE BEARERS-2013

02Vol-1 issue-3 May-2013

Knowledge is progressing by geometrical ratio and not by arithmetical. It is important that

we too become a part of this fast pace of progress. Not only assimilating but also disseminating is an

important way in propagating knowledge. Realization of the maxim ' Publish or perish' in the

world of science has inspired and encouraged many organizations to start their own journals. At

present information is only a click away. It is important to have electronic versions of the journal

so that the information reaches worldwide through the encompassing net.

The number of patients we see is enormous in comparison with the rest of the world. But

unfortunately we were not very keen to document. If at all we had proper documentation we would

have been the leaders in the profession. It is gladdening that the younger generation is more

enthusiastic, proactive and computer savvy.

I am really delighted to write the Foreword for this issue of JOMIDA. The quality of the

journal is impressive and the articles are informative and noteworthy. I take this opportunity to

congratulate the editor, president, secretary and other office bearers for this noble venture.

With best wishes

Prof. Dr. Varghese Mani

Oral and Maxillo Facial Surgeon

Dean,Mar Baselios Dental College


Authorship criteria All persons designated as authors should qualify for authorship, and all those who qualify should be listed. Each author should have participated sufficiently in the work to take public responsibility for appropriate portions of the content. One or more authors should take responsibility for the integrity of the work as a whole, from inception to published article. Authorship credit should be based only on 1.Substantial contributions to conception and design, or acquisition of data, or analysis and interpretation of data; 2.Drafting the article or revising it critically for important intellectual content; and 3.Final approval of the version to be published.

Conditions 1, 2, and 3 must all be met. Acquisition of funding, the collection of data, or general supervision of the research group, by themselves, do not justify authorship.

The order of authorship on the byline should be a joint decision of the co-authors. Authors should be prepared to explain the order in which authors are listed. Once submitted the order cannot be changed without written consent of all the authors.

For a study carried out in a single institute, the number of authors should not exceed six. For a case-report and for a review article, the number of authors should not exceed four. For short communication, the number of authors should not be more than three. A justification should be included, if the number of authors exceeds these limits.

Only those who have done substantial work in a particular field can write a review article. A short summary of the work done by the authors (s) in the field of review should accompany the manuscript. The journal expects the authors to give post-publication updates on the subject of review. The update should be brief, covering the advances in the field after the publication of article and should be sent as letter to editor, as and when major development occur in the field.

Sending the Manuscript to the Journal

Articles can be submitted to: [email protected], [email protected]

1.First Page File: Prepare the title page, covering letter, acknowledgement, etc., using a word processor program. All information which can reveal your identity should be here. Do not zip the files.



Dear Friends,

It gives me immense pleasure to meet you all through yet another edition of scientific journal of

Marthandam IDA (JOMIDA).I would like to take this opportunity to inform all that we have moved a step

forward by going online. JOMIDA is now available online at the link www.jomida.idamarthandam . I hope

this small step holds much importance in this technologically sound, fast moving world which will help all

the dental fraternity to access our journal from any part of this world. I strongly believe that the time is not

that far for us to get this journal indexed.

At this juncture I extend my sincere thanks to the advisory panel and the editorial team, the

president and hon. secretary of IDA Marthandam and IDA Tamilnadu state and also each and every

members of the IDA Marthandam family whose support and encouragement has played a significant role in

the successful journey of JOMIDA. The editorial board is eager to know the feedback from the readers. Any

suggestions, critics are always welcome which will help us to improve the quality of our journal and

help us to setup a standard that is equivalent to many national journals.

Ignorance is the curse of god;Knowledge is the wing wherewith we fly to heaven

- William Shakespeare

Hope this edition of JOMIDA will add few feathers on the wing of knowledge and enlighten all the

readers and fulfil their expectations.

Thanking you,

Yours Sincerely

Dr.R.Sambhu

Editor in Chief


Sanjiv Nair Oral Cancer - An update 10

13

Dr. J. Pratheep,Dr. S. Subramonian, Dr. V. Vasanthakumar

Strenocleidomastoid myocutaneous flap in the reconstruction of mandibular defect

Flexible denture for partially edentulous mouth -A reviewDr.Aravind Krishnan, Dr.Sreelal T, Dr.Anuroopa.A 16

Dr.Ruby Mathew,Dr.RamachandraPrabhakar,Dr.M.K.Karthikeyan, Dr.SaravananR.,Dr.RajvikramN., Dr.C.Vishnu Chandran

Early vs late treatment for class-2 mal occlusionA systematic review concerning orthodontic treatment efficiency

20

Dr.Anjana.S, Dr. Sreelal.T, Dr. Shibu.A,Dr. Anuroopa.A, Dr. Aparna Mohan

Minimally Invasive Prosthodontics - A review24

3D Dimension diagnostic aid -CBCT in OrthodonticsDr. Sathya Chandran,Dr.Ramachandra Prabakar, Dr.Saravanan,

Dr.Karthikeyan,Dr.Raj Vikram,Dr. Eshwara prasath

28

A. Leoney , P. S.ManoharanPorcelain laminates- a problem based treatment approach

32

Dr.Gajendra.V, Dr.Hema.G, Dr.Kathiga Kannan, Gene therapy in oral diseases -An over view

39

Dr. Thomas Varghese, Dr.KarthigaKannan, Dr. Jassim K A, Dr. Merin George,

Keratocystic odontogenic tumor of the mandible-A case report

Dr. Santhini G. Nair, Dr. S Rajesh

Minimal invasive dentistry -A new perspective

43

46

Dr,Aparna Mohan, Dr,Anuroopa A., Dr ,James Rex

Prosthodontic considerations in periodontally compromised dentition - A systematic approach 52

Dr. Ramandeep Singh Bhullar, Dr. S.Ram Kumar, Dr .Nanda Kumar, Prof. C. Ravindarn

Public Recognition of Our Speciality - A study56

Contents

A. Sri Kennath J Arul ,A. Sri Sennath J Arul ,Sonika Verma ,Rashmika Verma

Antioxidants and it’s role in Oral Cancer - A review 58


STATE PRESIDENT'S MESSAGE

I feel extremely happy to be communicating with you all through the medium of this issue.It is our privilege and responsibility as Dental Health Science professional to promote good and healthy practice by exchanging information and ideas on our experience and skills .

Continuous learning is mandatory for the growth and success of the dental practice.So I believe this journal of yours gives the general dental practitioners the necessary scientific data both clinically and academically to enhance their skills to deliver better dental care to their patients.

My best wishes for Team IDA Marthandam.

Vazhga Bharatham, Valarga IDA.

Dr. D. Senthil KumarPresident

IDA Tamil Nadu State [email protected].

Dear Members,

WARM GREETINGS!!! In this juncture I appreciate the office bearers for this humanity service to the peoples and our Dental fraternity. Our dental technologies are nowadays money minting factory. We are earning more from this field. We can get the knowledge from CDE Programs. Attend More Programs and Get more knowledge. Motivate your friends to attend more programs and also get knowledge. The great opportunity is coming to your country. FDI 2014 (DELHI). Register more. Our Tamilnadu State Dental Conference will be held on November 2013 at Pondicherry. We seek your participation. Through this journal once again I wish you all. Best of Luck….

Dr.C.SivakumarHon. State Secretary

IDA Tamilnadu State BranchCDH Chairman IDA - HO

Ph: 9443395351

STATE SECRETARY’S MESSAGE


Dear members,It is a great honour to share my views with you all as the Marthandam

branch president.During my presidential speech in December 2012,I stressed upon

continuing dental education programme for our members. So keeping in mind, my goal, scientific lectures are being held by the eminent speakers of our area.

I would like to appreciate the editor and the team of editorial board for working hard to bring out 3 issues of our scientific journal, which was appreciated by the IDA Tamilnadu state branch.

I have to specially mention our secretary Dr. Subromonian, Dr. Dias and Dr .S. Karthiga Kannan for their dedication to our association.

With warm regardsDr. G. Sathish Kumar

PresidentIDA Marthandam

Dear friends, rd I feel elated to reach you through the 3 issue of JOMIDA. We the

team MIDA,marching with pride and prosperity to reach the summit of success by commitment, dedication and encouraging support from all seniors and friends. I look forward to get the same in future, for successful running of MIDA and JOMIDA. Restless hard work, missionary thinking and unselfish effort is

rdmaterialized by the 3 issue of JOMIDA from the editor and his team. I thank the authors for their faith and belief on us. I thank the editorial board, Dr. Sujan and the printers, the review committee for their remarkable

rdwork to publish the 3 issue successfully. I thank the well wishers and other friends for their comments for the success of our journal.

Jaihind.Thanking you,

Yours sincerelyDr.Subramonian

Hon.SecretaryIDA Marthandam


PROF J G KANNAPPAN (Late)

Born: Dec 26, 1934

Died: Dec 30, 2010

Born on Dec 26, 1934, near Coimbatore, Tamilnadu, South India, he had received his basic schooling and education before graduating

from St Joseph's College, Trichy. The first dentist from his family, he graduated from the Madras Medical College before pursuing his

Master's in Dental Surgery (Orthodontics &Pedodontics), from the Nair Dental College in Mumbai. He went on to secure his Fellowship

on the same in London by the Govt. of India five year schemes, before returning to an Academic career at various institutions in

Tamilnadu and retired as the Principal of the Madras Dental College, Chennai. In realization of this generosity of the Govt. of India, Prof

Kannappan has devoted his services to the poor and needy of the nation. As a token of gratitude to Govt of India, Dr Kannappan has

established many endowments in the universities, schools and colleges for the benefit of youngsters.

He was instrumental in shaping numerous individuals, institutions and organizations and founder of various professional

societies including the Forensic Odontological Society of India, Indian Society of Dental Research etc. He was the president of the

Tamilnadu Dental Association, Indian Orthodontic Society, Forensic Odontological Society and the Indian Society of Dental Research

in addition to leadership roles in numerous dental and societal institutions.He was the recipient of the Leverhulme Fellowship in the

United Kingdom, innumerable awards from Indian Government, and honors from various literary, religious, philosophical, and

community-based organizations. He has authored articles and books on dental health and education in many languages and in

International Journals.His contribution to ISDR (Indian Society for Dental Research) as one of the founder members and to its growth to

the present status has been witnessed by many dental professionals.He is associated with IAFO in India, right from its inception. He has

nurtured this institution of Forensic Odontology and has proposed to medical universities to implement Forensic Odontology as a

separate subject in BDS curriculum and as a master degree.

Dr J.G.Kannappan is the Professor Emeritus of the TN Dr MGR. Medical University, Chennai. He has been teaching dental

and medical students for the last 51 years. He has taught, BDS, MBBS, MDS, and MSc Forensic Odontology students. He has guided

MPhil candidates too. He has authored and edited 32 books in medical and dental subjects in English, Tamil and Hindi and they are in the

world libraries. During the first TN Govt service, he has served rendering dental relief in all villages of Tamil nadu, thro" the mobile

dental van, which was donated to the Govt of TN by then Vice President of India, Dr Sir Radhakrishnan. His research in leprosy is unique

and that he has declared that leprosy is preventable and curable. His second research is about oral nutritional deficiency ulcers and

symptoms are due to GIT worms. He has done the autopsy of the head at the site of Rajiv Gandhi assassination in 1990. He has

formulated classification of dental appliances for the cleft palate patients and many more.He has been conferred prestigious DSc (Hon

Casua) degree of the TN Dr.MGR. Medical University, by His Excellency Shree Surjit Singh Barnala, Governor of Tamil Nadu.

Vol-1 issue-3 May-2013 10

Sanjiv Nair MDS

Facio Maxillary Surgeon

Cancer of the oral cavity predominantly are those

arising from the epithelium lining the upper aero

digestive tract which is referred to as Oral Squamous

Cell Carcinoma(SCC). These cancers because of its

location are easily identified and if diagnosed in its early

stages are near curable with minimal functional and

aesthetic morbidity.

The epidemiologic studies on Oral cancer have thrown

up a list of environmental factors directly or indirectly

being responsible for its cause. The primary risk factor

with a strong link are tobacco related products, both in its

smoked and smoke less forms ,alcohol, ultra violet light ,

radiation , genetic factors ,Human Papilloma Virus

(HPV) and malnourishment.

Tobacco predisposes to change in the oral mucosa

making it susceptible to alterations in cellular

morphology. This can trigger genetic changes leading to

alteration in cell devision.The exposure of the precursor

cells of the oral mucosa to more than one factors may

either have synergistic or additive effects in the

development of oral SCC.

Editor in chief-

JMOSI

Journal of maxillofacial

&oral surgery of India


Biology of Oral SCC : - Multiple exposures over a long

period of time causes sequential Deoxy ribose nucleic

acid (DNA) Damage . When the DNA damage exceeds

the Cell's DNA repair capability it leads to a permanently

altered gene referred to as mutation. Survival of the DNA

damaged Cell ( mutant cell) is however important to

allow its accumulation and progression to carcinoma.

Initiation of Carcinoma is a complex process facilitated

indigenously by break down of the body's immune

mechanism as well. Accessory factors such as

angiogenesis allows recruitment of blood vessels to the

mutant cells allowing it to sustain its division and growth .

Oral Squamous cell carcinoma has ability to spread or

metastasize due to its access to structures within the

connective tissue. Lymphatic metastasis is the

commonest form of cancer progression second to local

spread. Blood born metastasis as well as neural spread in

Oral SCC is well documented. The role of enzymes like

collagenase,heparinise allows degradation of physiologic

barriers facilitating the process. The presence of

metastatic tumor emboli within the reticulo endothelial

system is exposed to the same immune related

antagonistic actions as is faced by foreign body , survival

of these colony of cells would require a combination of

depressed immunity with facilitation of growth factor and

angiogenesis factor.

The key to management of Oral SCC is prevention

and early detection . Visual screening for oral cancer is the

most effective diagnostic tool . Use of adjuvant diagnostic

aids such as Toluidine blue , transepithelial oral cytology (

Brush Biopsy) , Tissue reflectors , HPV Screening may be

useful but lack of sufficient evidence based scientific

support .

Treatment of oral Cancer : Clinically identifiable

disease can be effectively biopsied . transoral Incisional

biopsy of obvious oral lesions would confirm the disease .

Further evaluation with the use of imaging modalities

will help in staging the disease (TNM Classification

staging) .Refer Table 1Joint Oncological clinics helps in planning the treatment and assisting the patient with the course of treatment. Joint meetings would require primarily the following specialists such as head and neck specialists; a Consultant Surgeon, a Consultant in Oncology and Palliative Care Consultant.

Treatment for the oral SCC would require surgical

resection with or without radiotherapy and chemotherapy.

The use of immunotherapy , gene therapy and anti

angiogenesis therapy although show promise are very

much in its infancy.

Head & Neck SCC being a loco regional disease

primarily , Surgery followed by radiotherapy holds

great promise both in disease control and quality of

life.Surgical ablation would mean excision of the

primary tumor with a wide margin and addressing the

metastatic neck. Inclusion of the clinically and

radiographically negative neck in a neck dissection

varies from centre to centre and is site specific . This is

reffered to as staging neck dissection or prophylactic

neck dissection .

The Nodes in the neck are grouped into V levels

and total removal of level I level V along with the

Internal Jugular vein, Spinal accessory Nerve and the

sternocleidomastoid muscle is referred to as Radical

neck dissection (RND). Preservation of one or more of

the functionally important structures such as spinal

accessory nerve, Internal Jugular Vein and

sternocleidomastoid muscle while dissecting the rest of

the lymph nodes is Modified RND Selective Neck

Dissection is excision of one or more group of lymph

nodes that drain the primary site directly or indirectly.

Reconstruction in oral cancer surgery is of paramount

importance due to its impact on aesthesis and function .

Restoration of form and function and total rehabilitation

of the patient may require counselling and vocational

therapy.

Principles of reconstruction involves

replacement of ablation tissue with identical tissue from

the patient's own body. Local ,Regional or

Microvascular flaps help in obtaining tissue match and

texture. The survival of the transplanted tissue depends

on its vascularity . Use of microvascular free tissue

transfer permits ideal reconstructive choices. The radial

forearm free flap for soft tissue reconstruction and

fibula for bony replacement seems to be work horse of

modern day reconstructive surgery.

Radiotherapy - The use of ionizing radiation dates

back to the end of the nineteenth century following

discovery of radium by Marie and Pierre Curie. The

principle involved destruction of rapidly dividing cells

including malignant cells with radiation. Post surgical

Radiotherapy is far more effective than presurgical

radiation in eliminating microscopic disease not

removed with surgery. Radiation acts by ionizing the

cellular water molecule into active free radicals which

in turn affects the DNA of cancer cells. The optimum

time to irradiate is 6-8 weeks post surgery during the

intermediate healing phase.


A total of 6000- 7500 cGy in fractional dozes is

given to the target area which irradiates the primary site

and the susceptible neck.The normal side effects of

radiation incude Radiation mucositis, Xerostomia, Taste

impairment and Osteoradionecrosis.Side effects of the

Radiotherapy can be minimized by employing adequate

dental care, administration of agents that protects

salivary tissue during radiation , prevention of secondary

infection .

Advances in radiation technology includes

1.Super voltage irradiation Linear accelerator that

spare superficial structure while targeting deeper tissue.

2.Brachytherapy Implanted radiation sources in the

form of seeds or needles allow constant radiotherapy

with higher tissue death.

3.Neutron beam irradiation damages tissue more

directly and are effective on hypoic tumors.

4.Hyperfractionated therapy is doubling the radiation

doze by twice a day treatment.

5.Use of radiosensitizer and oxygen enhancement

therapy makes the target cells more susceptible to

radiation .

The role of Chemotherapy in Oral SCC was much

debated in the past .The main reason being it was

considered a loco regional disease effectively managed

with surgery with or without radiotherapy. This

however gave way to combination of Chemo radiation

as an effective technique in Organ preservation

especially with larynx and Oropharynx. The rationale

was founded upon high response rates in patients with

Head and Neck SCC to a variety of agents including

Methotrexate, Vinblastine, 5-Flurouracil, Cisplatin,

Carboplatin and the taxoids either in combination or

alone. These response rates were found to be 50% in

previously untreated patients .

Neo-adjuvant or induction chemotherapy

schedules also help in downstaging the disease prior to

definitive local therapy. The simultaneous use of

combination of Chemotherapy with radiotherapy is

reverred to as adjuvant or combined therapy and was

found as effective without surgery and used for

laryngeal SCC.

Adjunctive therapies such as gene therapy involves

trancfer of genetic materials into cancer cells with

selective destruction of malignant cells while sparing

normal cells thus overcomung the defeciencies of CT

and RT.

TNM Staging of oral cavity squamous cell carcinoma

The targeting and transport of genetic material

does appear to be the biggest obstacle. Use of technology

such as nanotherapy is in experimental stages. The

suppression of TGF ,Angiogenic factors are other alternates

to prevent cancer progression. A better understanding of

molecular biology and the ambitious human genome

project does allow advances in the research and

development of targeted therapy

Even with advances in surgical techniques ,and

other forms of therapies cure may be impossible and life can

be maintained with the aim of pain control, and preservation

of dignity. Selective use of surgery to reduce tumour bulk to

reduce pain and preserve function. Palliative radiotherapy

,nutritional support with gastrostomy feeding tubes, Pain

control with morphine or other narcotic analgesics, Home

healthcare facility during terminal stages allow death with

dignity to such patients.

Table: 1

T0 - no evidence of primary tumour

Tis - carcinoma in situ

T1 - tumour 2 cm or less in greatest dimension

T2 - tumour greater than 2 cm and less than 4 cm in greatest

dimension

T3 - tumour greater than 4 cm in greatest dimension

T4 - tumour invades adjacent structures (mandible, maxilla,

skin, extrinsic muscles of the tongue)

Primary tumour staging (T)

Tx - tumour cannot be assessed

Nodal status (N)

N0 - no regional nodal metastases

N1 - single ipsilateral node, = 3cm

N2

N2a - single ipsilateral node, 3-6 cm

N2b - multiple ipsilateral nodes, < 6 cm

N2cbilateral nodal metastases OR contralateral nodal

metastases < 6 cm

N3 : any nodal metastasis > 6 cm

Metastases (M)

M0 - no metastases

M1 - distant metastases present

Nx - nodes cannot be assessedNodal staging is the same

for SCCs of the oral cavity,

oropharynx, hypopharynx

and larynx.


Introduction:

Defect in the oral cavity can be reconstructed using a flap with skin and the muscle to reconstruct defects in the oral cavity. SCM fits the criteria and permits one-stage reconstruction at the time of the primary resection and eliminates the need for skin

1grafts to the donor sites .Partial epithelial loss of the skin paddle occurs

in some cases and surviving dermis became 2

resurfaced with epithelium .Raising a SCM flap based on the perforating vessels of the superior thyroid vascular pedicle increases the arc of rotation and

3applications for the flap improved .Facial paralysis repair by the pedicled SCM

muscle restores both static and dynamic symmetry of nose and mouth with improvement in facial expression.

The upper third of the SCM muscle was constantly supplied by branches of the occipital artery. The middle third of the SCM muscle received its blood supply from a branch of the superior thyroid artery (right SCM/left SCM: 53%/53%), the external carotid artery (27%/20%), or branches of both (20%/27%).

The lower third of the muscle was supplied by a branch arising from the suprascapular artery (73%/73%), the transverse cervical artery (7%/13%), the thyrocervical trunk (13%/13%), or the superficial cervical artery (7%/0%).

The neoprene-latex injected into the subclavian artery reached the four lower levels in all SCMs (the middle third of the SCM). In 13% of the SCMs, this injection also reached level II (the upper third of the SCM). With a double injection (inferior and middle pedicles), levels I and II were reached in

5100% of the cases .

Abstract

Reconstruction for oral cancer and severe trauma defect plays an important role considering the form and function. Selecting a flap to reconstruct the defect depends on the size and position of the defect. Considering the donor site morbidity, time and expense, regional pedicled flaps dominates free flap. Some of the regional pedicled flaps are pectoralis major myocutaneous flap, temporalis flap, trapezius flap, buccal fat pad flap and sternocleidomastoid flap (SCM). We present the technical details of harvesting a SCM in the reconstruction of mandibular defect.

Key wordsReconstruction,Myocutaneous Flap, Mandibular Defect, Sternocleidomastoid.

1Dr. J. Pratheep,2Dr. S. Subramonian,

3Dr. V. Vasanthakumar

1) & 2) Reader, Rajas Dental College, Kavalkinaru

3) Reader, CKS Teja Dental College, Tirupathi

Vol-1 issue-3 June-2013 14

6Advantages :

1.Contour the soft tissue defect

2.Re animate facial paralysis

3.Transposed with or without segment of the clavicle and/or sternum as a composite pedicle flap for reconstruction of the mandible

4.Reconstruct floor of mouth

5.To protect the carotid artery

6.It may assist in shoulder elevation following poliomyelitis when transposed to the acromial process of the clavicle.

7Disadvantages :

1.Upper SCM composite muscle flap is poorly viable

2.Blood supply to the skin paddle based over the lower third of the muscle is similarly unreliable

3.Upper and lower ends of the muscle are areas of oncological significance

4.Inclusion of clavicle for mandibular reconstruction is usually no longer required as superior flaps are available

Technique:

Neck incisions can be modified according to the requirement of the surgeon considering access, nodal clearance, previous incisions, site of the tumor, pre or post op radiotherapy and the reconstruction plan. Here we have used the Schobinger incision with the vertical limb ending over the paddle of skin and the muscle.

The skin is prepared and the incision marked and made. Considering the clearance of the disease and reconstruction, the skin flap was raised in a standardized fashion.

Skin incision made with no. 15 blade followed by cautery and dissect below the sub-platysmal plane. Posterior neck was dissected with utmost care as the damage of the SCM muscle occurs and we may miss the plane and end up in severe bleeding.

Proper retraction in upward direction helps the operator to enter the sub-platysmal plane and identify the SCM muscle. Marginal mandibular nerve was sacrificed. External jugular vein and anterior jugular veins were tied as we isolate the SCM muscle.

Segmental mandibulectomy done and level I to IV was cleared. The defect was evaluated and thereconstruction flap was selected.

Pre-operative frontal Pre-operative intra oral

Defect

Diagramatic view

Outline


The sternocleidomastoid (SCM) muscle has 3 pedicles. The superior pedicle is a branch given off in about 70% of cases by the occipital artery, the middle is formed by a branch of the superior thyroid artery, and the inferior pedicle arises from the suprascapular

8or the transverse cervical artery . Further minor arterial branches enter in between.

The shoulder was extended with sand bag. The margins and the skin paddle of the muscle drawn with a marker.

The muscle was harvested from the lower sternal origin and clavicular origin with skin paddle. The operator should have a proper vision of the flap's borders. Slowly elevate the muscle with utmost care as the pedicles should not be traumatized.

Once the flap was harvested the length of the flap was evaluated and then suturing was done without any tension.

Reconstruction plate can be used to gain the contour of the mandible. The SCM flap can be placed enclosing the reconstruction plate and sutured with the adjacent muscles and the skin paddle can be sutured with the mucosal tissues.

Conclusion:SCM flap is a simple and effective flap for the

reconstruction of the oral defect which avoids or helps in addressing many problems that happens with other regional myocutaneous flaps. It can alsobe used for primary reconstruction sparing the free flaps for secondary reconstruction if needed after clearance of recurrence.

References:1.Ariyan S. “The sternocleidomastoid myocutaneous flap”. Laryngoscope. Apr;90(4):676-9, 19802.Ariyan S. “ One stage reconstruction for defects of the mouth using a sternomastoidmyocutaneous flap”. PlastReconstr Surg. May;63(5): 618-25, 19793.Avery CM. “The sternocleidomastoid perforator flap”. Br J Oral Maxillofac Surg. Oct;49(7):573-5, 20114.Yang C, Cui L. “Transposition of pedicled sternocleidomastoid muscle for repair of facial paralysis in late stage”. ZhongguoXiu Fu Chong Jain WaiKeZaZhi. Jan;16(1): 48-50,20025.Leclere FM, Vacher C, Benchaa T. “Blood supply to the human sternocleidomastoid muscle and its clinical implications for mandible reconstruction”. Laryngoscope. Nov; 122(11):2402-6, 20126.Conley J, Gullane PJ. “The sternocleidomastoid muscle flap”. Head Neck Surg. Mar-Apr; 2(4): 308-11,1980

th7.Stell and Marran's head and neck surgery 4 ed;20008.Marx RE, McDonald DK. “The sternocleidomastoid muscle as a muscular or myocutaneous flap for oral and facial reconstruction”. J Oral Maxillofac Surg. Mar;43(3):155-62, 1985

Post operative -frontal Post operative -lateral

Specimen

Harvest

Recon plate

Suturing


1 2 3Dr.Aravind Krishnan, Dr.Sreelal T, Dr.Anuroopa.A

(1)Post Graduate, (2) Professor and HOD, (3) Reader

Department Of Prosthodontics, SMIDS, Kulasekharam

Partial edentulism is one of the most relevant oral

conditions noticed in dental practice .A complete

functional and esthetic rehabilitation of their patients is

of prime concern for the success of the general practice.

But in certain conditions where the regular treatment

modalities has to be changed or modified in order to

enhance the quality of treatment, a flexible denture is an

alternative treatment option. Flexible dentures are Nylon

based thermoplastic material which are Flexible in nature.

In 1940's , Arpad and Tibor Nagy's research lead

to the introduction of a newer thermoplastic,Valplast

material.Valplast (Valplast Int. Corp. - USA) and

Flexiplast (Bredent - Germany) were first introduced to

dentistry in the 1950s,which were similar grades of

Polyamides (nylon plastics).Rapid Injection Systems

(currently known as The Flexite Company - USA),

originated in 1962, introduced the first Flexite

thermoplastic which was a flouropolymer (a Teflon-type of

plastic).Acetal was first proposed as an unbreakable

thermoplastic resin removable partial denture material in

1971.DENTSPLY introduced the Success FRS, “flexible

resin system” which utilizes a flexible tissue colored

thermoplastic resin for flexible partial dentures. Cosmetic

Dental Materials introduced “Aesthetic Perfection T”

which is a new line of thermoplastic Acetal, Acrylic, and

Polycarbonate materials that can be used in most

thermoplastic procedure.

Abstract

Key words

Thermoplastic, Nylon, Flexible, Proflex

Management of situations like unilateral or bilateral

undercuts conventionally includes alteration of the

denture prosthesis bearing area, adaptation of the

denture base, careful planning of the path of insertion

and the use of resilient lining material But in certain

conditions where the regular treatment modalities has to

be changed or modified in order to enhance the quality

of treatment, a flexible denture is an alternative

treatment option. The Article reviews about the various

Flexible denture materials, advantages, disadvantages,

indications, contra indications and various

commercially available flexible denture products


Indications of Flexible denture includes challenging cases

like Unilateral or bilateral undercuts, pediatric patients and

cleft palates .It is an ideal replacement for acrylic when

patients are allergic to denture acrylics and in patient with a

history of repeated partial denture frame breakage. It is an

easy and affordable alternative to implants or fixed partial

dentures and also for tooth or tissue-coloured clasps in high

esthetic areas. Additional applications comprises of

cosmetic gum veneers,bruxism appliances, implant

retained over-dentures , full dentures for patients with

protuberant bony structures or large undercuts, unilateral

space maintainers ,temporary prostheses (short and long-

term), obturators and speech therapy appliances,

orthodontic devices, occlusal splints and sleep apnea

appliances, anatomical bite restorer (used during full

mouth rehabilitations),sleep apnea appliances. Flexible

partials for people with special needs are athletes, police

and firefighters, military personnel, prisoners and prison

officers, any person who might be exposed to physical

harm or injury.

Although flexible dentures are treatment choice

for various clinical scenarios ,it is contraindicated in

following situations such as deep overbites (4mm or more)

where anterior teeth can be dislodged in excursive

movement, few dentition with minimal undercuts for

retention, situations where there is less than 4 mm of inter-

occlusal space in the posterior area, bilateral free-end distal

extensions with knife edge ridges or lingual tori in the

mandible and bilateral free-end distal extension on maxilla

with extremely atrophied alveolar ridges.

There are various types of flexible denture base

materials available; they are thermoplastic Acetal,

Thermoplastic polycarbonate, thermoplastic Acrylic and

thermoplastic Nylon.

Thermoplastic Acetal is available in basically

two forms; homo polymer and co polymer .Acetal as a

homo-polymer has got good short term mechanical

properties, where as co-polymer has better long-term

stability.

They are very strong, resistant to wear and fracture, and is

quite flexible. Thermoplastic acetal is considered as an

ideal material for pre-formed clasps in partial dentures,

unilateral partial dentures, cast partial denture

frameworks, provisional bridges, occlusal splints, and

implant abutments. Acetal resins resist occlusal wear and

are well suited for maintaining vertical dimension during

provisional restorative therapy. It does not have the natural

translucency and vitality of thermoplastic acrylic or

polycarbonate, hence used as short-term temporary

restorations.

Thermoplastic Polycarbonate is a polymer chain

of bisphenol-A carbonate. Compared to Acetal they are

very strong, resistant to fracture but flexible during

occlusal force, hence consequently will not maintain the

vertical dimension .They are ideally suited for provisional

crowns and bridges and not suitable for partial denture

framework. One of the major advantages is that it exhibits

excellent esthetic properties.

Thermal polymerized PMMA is yet another

material which is easy to adjust, handle and polish,

relineable and repairable at the chair-side, available in

both tooth and gingival colors, translucency and vitality,

providing excellent esthetics. But it demonstrates high

porosity, high water absorption, volumetric changes and

residual monomer .They have got a poor impact

resistance, with an adequate tensile and flexural strength

for a variety of applications. .Flexite M.P, a thermoplastic

acrylic, is a special blend of polymers with the highest

impact rating of acrylic.It has a surface hardness of 55-65,

making it popular for bruxism appliances as well as

dentures.Thermo plastic Nylon is a resin derived from

diamine and is a dibasic acid monomers with high physical

strength, heat resistance and chemical resistance.It is

easily modified to increase stiffness and wear

resistance.They have excellent balance of strength,

ductility and heat resistance which is hence the best

candidate for metal replacement applications.


They have got inherent flexibility and hence used primarily

for flexible tissue born partial dentures. They does not have

enough strength to use for occlusal rest seats, and won't

maintain vertical dimension when used in direct occlusal

forces.

Thermoplastic nylon is injected at temperatures from

274 to 293 degrees Celsius and has a specific gravity of

1.14. Mold shrinkage amounts to 0.014 in/in. The tensile

strength is 11000 psi and the flexural strength is 16000 psi.

Nylon is a little more difficult to adjust and polish, but the

resin can be semi translucent and provides excellent

esthetics for flexible tissue born partial dentures.

Advantages of thermoplastic materials include

predictable long-term performance, stable and resist

thermal polymer unzipping, high creep resistance ,high

fatigue endurance ,excellent wear characteristics ,solvent

resistance, very little or no free monomer, no porosity,

exhibit higher dimension and color stability, more flexible

and stronger than their traditional counterparts.

Elastomeric resins are added to the resin polymer

formulas to create greater flexibility which in turn reduces

fracturing. The materials are reinforced with glass filler or

fibers to enhance their physical properties and they can

produce single cast or pressed restorations that are strong,

lightweight, flexible appliances in tissue or tooth color

matched materials that never need adjusting.

Commercially available products are Valplast ,Duraflex

,Flexite,Proflex,Lucitone ,Impak ,in which Valplast and

Lucitone are Monomer free.

Pro-flex were introduced by Pickett

dental Lab in 1998 and is indicated in anatomical

considerations like bilateral undercuts. It is Hypoallergenic

and is aesthetic, tough, durable and dense. Valplast are used

as Partial dentures and unilateral restorations They are

highly biocompatible nylon thermoplastic with unlimited

design versatility. Valplast are virtually invisible but is

expensive and non invasive. Special instructions for

valplast flexible denture wearer include -Clean Valplast

flexible dentures regularly.

Valplast dentures are to be soaked in water for 10-15

minutes a day, or overnight at least three times a week.

Loose particles can be removed with the use of a sonic

denture cleaner, or by placing the appliance under running

water. Brushing a Valplast appliance is not recommended

as this may remove the polish and roughen the surface over

time. Sunflex are strong and biocompatibe They are

unbreakable, light weight .Tissue coloured clasps are the

major advantages of this type of partial dentures. Sun Flex

are more stain resistant and has got a Perfect degree of

flexibility. Another advantage of this is that Dentures will

not warp or become brittle and Aesthetically superior

Functional Benefits of the Flexible Material

1. Flexibility of the material is an important benefit and it

helps to shift the burden of force control from design

features of the appliances to the properties of base material

2. Leverage is a critical component of RPD. Flexible denture

reduces leverage effects of its extensions and hence good

support and retention is achieved

3. Occlusal rests and guide planes need not be prepared in

abutment teeth.

4. Stress distribution of Flexible denture is important and is

accomplished by flexibility of major connector and acts as

a stress breaker.

Advantages include more

acceptable esthetics, has good flexibility like titanium,ease

of insertion in the mouth with alveolar undercuts or even if

there is slight shifting of the remaining teeth over time, the

flexibility of the denture material, allows the use of

prosthesis with little adjustment.There is no need of

modification of the remaining teeth and hence can be used

for patients with tilted teeth. It is heated up in hot water for

about a minute and can easily be adjusted and inserted in

the undercut area and rebasing is possible.

But the dis advantages are that being a plastic

material,it cannot be made into thin sections like metal ,and

it takes longer time for patient to get used to a flexible

partial denture.It does not conduct heat and cold like

metal.The remaining teeth have to be in fairly good

periodontal health.


Flexing causing unfavorable forces that in turn result in bone

loss.It is highly expensive.It requires more chair-side time for

adjustment and need special instruments (knives and

polishing kit). It is hard to repair if fractured ,hence only

rebasing is possible

Conclusion:

Dentistry is been updated ,researched and perfected

in order to provide the patient with efficient and quality

treatment and modify their life style.Use of Flexible denture

has been advocated by many prosthodontists because of its

advantages and the general characteristic features .Flexible

denture can be considered as an effective alternative in

various partial edentulous conditions that require tedious

surgical skills and time consuming procedures.

References:

1. “Flexible dentures” an alternate for rigid dentures? Volume 1 Issue 1

Journal of Dental Sciences and Research ,Dr. Sunitha N Shamnur, Dr.

Jagadeesh KN,Dr. Kalavathi SD, Dr. Kashinath KR

2. Flexible denture base material: A viable alternative to conventional

acrylic denture base material Contemp Clin Dent. 2011 Oct-Dec; 2(4):

313317. J. P. Singh, R. K. Dhiman, R. P. S. Bedi, and S. H. Girish

3. Flexible Denture for Partially Edentulous Arches - A Case Report

Journalofdentofacialsciences Vol. 1 Issue 2 Laxman Singh Kaira, H R

Dayakara, Richa Singh

4. Flexible removable partial denture for a patient with systemic sclerosis

and microstomia General Dentistry November /December 2007 Nachum

Samet .Schmel Tau ,Michael Findler ,Srinivas.M,Mordechi Findler

5. Flexible Partial Dentures - A hope for the Challenged Mouth People's

Journal of Scientific Research Vol. 5(2), July 2012 G.K. Thakral,

Himanshu Aeran, Bhupinder Yadav, Rashmi Thakral

6. An evaluation of the hardness of flexible Denture Base Resins Health

Sciences 2012 Dr.Sheeba Gladstone,Dr.Sudeep.S,Dr.Arun Kumar


1Dr.Ruby Mathew,

2Dr.RamachandraPrabhakar,

3 4Dr.M.K.Karthikeyan, Dr.SaravananR.,

5 6Dr.RajvikramN., Dr.C.Vishnu Chandran

rd(1) 3 year postgraduate,( 2) Professor and HOD,(3& 4) Professor, (5) Reader,( 6)Senior lecture,Department of orthodontics, Thai Moogambigai Dental College.

Introduction:There is lack of consensus regarding the degree of success

of different treatment modalities applied during the early 6,12to late mixed dentition stages. The concept of early

treatment is controversial.Some define it as removable or

fixed appliance intervention in the primary ,early mixed

(permanent first molars and incisors present),or midmixed

(inter-transitional period,before the emergence of first 6,12

premolars and permanent mandibular canines). Early

treatment modalities of class II division I malocclusion

involves headgear,functional appliance such as 3

bionator,herbst appliance. Primary goals of early

treatment is to restrain and control excessive vertical

maxillary growth especially in the posterior

region,preventing downward and backward rotation of the

mandible and possibly even producing forward rotation of 11

the mandible with continued growth.

Abstract

Key words

The aim of this study was to assess the

efficiency of early and late class 2 division-1

treatment in the mixed and permanent dentition by

systematically reviewing the literature.Literature

search was performed randomly over the period

1995 to 2012.The criteria includes randomized

clinical trials of early versus late class - II treatment,

statistically significant differences were observed

between the treatment and observation groups.The

search strategy resulted in 17 articles 2phase

treatment started before adolescence in the early

permanent dentition.Early treatment also appears to

be less efficient,in that it produced no reduction in

the average time a child is in fixed appliance during

second stage of treatment and did not decrease the

proportion of complex treatment involving

extractions or orthopedic surgery.

Early vs. late treatment, class II division I,systematic

review.

One rationale for early treatment is that correction of

the visible aspects of malocclusion at an early stage in a

child's maturation will prevent the development of poor self-16concept. self-concept defines an individual's organization of

self-attitudes,including perceptions and beliefs with respect 16to body structure and appearance,referred to as body image.

Materials and Methods: To identify all the studies that examined the

relationship between early vs. late orthodontic treatment for

class - II division 1 malocclusion. The survey covered the

period from 1995 to 2012 with the interest in the particular

heading outcomes of early vs. late treatment for class - II

division 1 malocclusion. Self-concept measures using Piers-

Harris scale were included in the trials. An 80 item forced

choice self report designed to quantitatively assess how

children feel about themselves. Inconsistencenies and

response biases were assessed using the Piers-Harris

methods.

The following characteristics were used for the

study: Preoperative and postoperative dental cast,

photographs and lateral cephalometric radiographs and

plaster models are taken. Treatment duration and patient

compliance were evaluated.

The Piers-Harris Children's Self-Concept Scale

1.Behaviour

2. Intellectual school status

3.Physical appearance attributes

4.Anxiety

5.Popularity

6.Happiness satisfaction

16

17

13

14

12

10

The extent to which a child admits or denies problematic behavior

Self-assessment of abilities with respect to intellectual and academic task,

Attitudes concerning physical characteristics as well as attributes

General emotional disturbance and dysphoric mood

Evaluation of popularity with classmates,being chosen for games,

A general feeling of being a happy person and easy to get along with,

including general satisfaction with school and future expectations.

such as leadership and the ability to express ideas

and ability to make friends.

and feeling generally satisfied with life.

TOTAL

80SCORE

EXPLANATION OF MEASURENO. OF ITEMS MEASURE


Discussion:J.F.CAMILLA TULLOCH, CEIB PHILLIPS AND WILLIAM

3R. PROFFIT evaluates the influences on the outcomes of early

treatment for malocclusion.In the first phase of a class - II

randomized clinical trial of early versus late classII

treatment,the change in jaw relationship,reduction in ANB

angle was favorable in 76%of the headgear,83% of the

functional appliance and 31%of control(observation

only)groups.75%of children undergoing early treatment with

either headgear or a modified bionator,experience a favorable or

highly favorable reduction in sketetal discrepancy.Cooperation,

measured as the number of hours of reported wear,or the clinical

assessment of compliance,explained little of the variation in

treatment response.

J.F.CAMILLA TULLOCH,CEIB PHILLIPS AND WILLIAM 1R. PROFFIT evaluates the treatment objectives of

preadolescent children with overjet greater than 7mm were

randomly assigned to observation only,headgear

(combination),or functional appliance(modified bionator) and

were monitored for 15 months.It concludes that children with

moderate to severe class II malocclusion,early treatment

followed by later comprehensive treatment on average does not

produce major differences in jaw relationship or dental

occlusion,compared with later on stage treatment. 4

JULIA VON BREMEN AND HANS PANCHERZ assesses the

efficiency of early and late class II division I treatment in the

mixed and permanent dentition.This articles examined 204

patients with class II division I malocclusion treated in the early

mixed dentition (n=54), late mixed dentition (n=104) and

permanent dentition (n=46).Patient treated exclusively with

fixed appliances had a shorter treatment duration (19

months)for herbst and 24 months for multibracket than did

patients treated with functional appliances or a combination of

appliances (38 months for functional appliances and 49 months

for a combination).It concludes that for both duration and

outcomes, class II division I malocclusion treatment was more

efficient in the permanent dentition than it was in the early or

late mixed dentition.Furthermore treatment with fixed

appliances was more efficient than treatment with removable

appliances.

LORNE D. KOROLUK,CAMILLA TULLOCH AND CEIB 5

PHILLIPS investigate incisor trauma in children with overjets

greater than or equal to 7mm who were enrolled in a clinical trial

of II phase early orthodontic treatment for class II

malocclusion.In phase 1,children were randomly assigned to

treatment in the mixed dentition with either modified bionator

or combination headgear or a group in which treatment was

delayed until the permanent dentition.Early growth

modification treatment might have some effect on the incidence

of trauma,but to be effective it might have to be initiated soon

after the eruption of the maxillary incisors.

J.F.CAMILLA TULLOCH, WILLIAM R.PROFFIT AND 11CEIB PHILLIPS talks about a 2 phased,parallel,randomized

trial of early (preadolescent) vs. later (adolescent)treatment

for children with severe overjet 7mm class - II

malocclusion.Favorable growth changes were observed in

about 75% of those receiving early treatment with either a

headgear or a functional appliance.After a second phase of

fixed appliance treatment for both the previously treated

children and the untreated controls,however early treatment

had little effect on the subsequent treatment outcomes

measured as skeletal change,alignment and occlusion of the

teeth,or length and complexity of treatment.The differences

created between the treated children and untreated control

group by phase 1treatment before adolescence disappeared

when both groups received comprehensive fixed appliance

treatment during adolescence.This suggests that 2 phase

treatment started before adolescence in the mixed dentition

might beno more clinically effective than 1-phasetreatment

started during adolescence in the early permanent

dentition.Early treatment also appears to be less efficient,in

that it produced no reduction in the average time a child is in

fixed appliances during a second stage of treatment, and it did

not decrease the proportion of complex treatments involving

extractions or orthognatic surgery.

TSUNG-JU HSIEH, YULIYA PINSKAYA AND EUGENE 6

ROBERTS compares the treatment outcomes of early

treatment (mixed dentition)with that of late treatment (early

permanent dentition)using objective evaluation

criteria.Pretreatment and post-treatment records of all

patients completed from 1998 to 2000 in the graduate

orthodontics clinic at the Indiana university school of

dentistry were evaluated by the American board of

orthodontics objective grading system and comprehensive

clinical assessment.Two definitions of early treatment were

used in this study 1. All patients started in the mixed dentition

with early treatment objectives and 2. Female

individualswere more than 10 yrs and male individuals were

more than 10.5yrs of age when treatment began.Comparison

of the final results between early vs. late treatment groups

showed that the early treatment group had significantly

longer treatment time and worse comprehensive clinical

assessment scores than the late treatment.

ADEBIMPE O.IBITAYO,VALMY PANGRAZIO-

K U L B E R S H , J E F F B E R G E R A N D B U R C U 10

BAYIRI compares treatment outcomes of growing and non-

growing patients characterized by mandibular class - II

retrusion and increased vertical dimension.Seventeen

patients of 9yrs were treated with a bionator fabricated with

posterior bite blockand high pull headgear,while 15 patients

of 23yrs received Lefort 1 osteotomy for maxillary impaction

and mandibular advancement.In the functional appliance

group,the mandible showed a more favorable growth

direction and rotation.


However,the pause between phase1 and phase2 became a

problem since overjet reappeared in a number of patients.This

leads to a prolonged retention phase that extended beyond 3 2

years in some instances.

David Chin concludes that early growth modification

might have some effect on the incidence of trauma with the

expected cost of trauma per child to be less for those who had 172 phase orthodontic treatment.

Early treatment for malocclusion has shown class - II

that favorable growth responses,although quite possible and 7 even likely,are not always achieved. but early treatment

intervention improves Dentofacial attractiveness may well 16improve a child's social interactions. Phase 1 therapy does

not gives any significant impact on the vertical dimension of 9the posterior dentoalveolar sectors of the dental arches. Early

orthodontic treatment produced more stable long term

orthodontic results and yield improved mandibular incisor 8

stability. To initiate “growth modifications”procedures

before the late mixed dentition ,functional appliance do

work,their use represents a practice management decision,not 12

a biological treatment imperative. Recent findings

questioning the efficiency of early treatment have forced

orthodontists to ask themselves whether their decision to

“start now”is being influenced too heavily by practice - 13

management considerations.

Both the functional appliances and orthognatic surgery

resulted in similar dentoskeletal treatment changes.Both

groups had stable results over time and finished treatment

with similar cephalometric measurements.

JAMESR.WORTHAM,CALOGERO DOLCE,SUSAN

P.MCGORRAY,HUONG LE, GREGORY J.KING AND 14

TIMOTHY T.WHEELER compares the arch dimension

changes in phase 1 and phase 2 treatment of class - II

malocclusion.This was prospective randomized clinical

trial conducted in the department of orthodontics at the

university of florida between 1990 to 2003.During the first

phase 86 patients were treated with the bionator,93 were

treated with headgear/biteplane and 81 served as the

observation group.For phase 2 all subjects were then treated

with full orthodontic appliances.Arch dimension were

taken at the baseline,at the end of early treatment,beginning

of orthodontic appliance and at the end of orthodontic

treatment.There were no differences after phase1 or phase 2

treatment of malocclusion. class - II

References:

1.J.F.CAMILLA TULLOCH, CEIB PHILLIPS AND

WILLIAM R.PROFFIT:Benefit of early class2 treatment

:progress report of a two phase randomized clinical

trial.AJODO 1998;113:62-72.

2.ANTHONY A. GIANELLY:One-phase versus two-phase

treatment.AJODO 1995;108:556-9.

3.J.F.CAMILLA TULLOCH,WILLIAM R.PROFFIT AND

CEIB PHILLIPS: Influences on the outcome of early

treatment for class2 malocclusion.AJODO 1997;111:533-42.

4.JULIA VON BREMEN AND HANS

PANCHERZ:Efficiency of early and late class2 division 1

treatment.AJODO 2002;121:31-7.

5.LORNE D. KOROLUK,J.F.CAMILLA TULLOCH AND

CEIB PHILLIPS:Incisor trauma and early treatment for

class2 division 1malocclusion.AJODO 2003;123:117-26.

6.TSUNG-JU HSIEH,YULIYA PINSKAYA AND EUGENE

ROBERTS:Assessment of orthodontic treatment

outcomes:early treatment versus late treatment.AO

2005:75;162-170.

7.Z.MIRZEN ARAT AND MELIHA RUBENDUZ:Changes

in dentoalveolar and facial heights during early and late

growth periods:a longitudinal study.AO 2004;75:69-74.

TIZIANOBACCETTI,LORENZOFRANCHI,VERONIC

A GIUNTINI,CATERINA MASUCCI,ANDREA 15VANGELISTI AND EFISIO DEFRAIA compare the

outcomes of prepubertalvs pubertal treatment of deepbite

patients with a protocol includingbiteplane and fixed

appliances.A total of 34 patients received treatment with

removable biteplane appliances in the mixed dentition at a

prepubertal stage in the mixed dentition(early treatment

group),24 patients were treated at a pubertal stage in the

permanent dentition( late treatment group).All subjects of

both groups were reevaluated after an average period of 15

months after the completion of fixed appliance

therapy.Treatment of deepbite at the puberty in the

permanent dentition leads to significantly more favorable

outcomes than treatment before pubertyin the mixed

dentition.

Conclusion:

In this study it concludes that,long treatment time,related to

continuous phase1 to phase2 treatment was associated with

poor compliance during the later stages of phase2 6

treatment. Mcnamara et al demonstrated an age dependent

mandibular growth response with the use of the functional

regulator2 appliance when they recorded more mandibular

growth noted in younger patients.He concludes that

mandibular response favoured later intervention that is

observed 4.0 mm/year in older patient,while 3.2mm/year in 2younger patients.

Wieslander also attempted to achieve the “best of orthopedic

worlds”by intensive phase1 treatment of young patients,the

protrusions were reduced rapidly,and the profiles

straightened in phase1.


8.TAKANOBU HARUKI AND ROBERT M. LITTLE: Early

versus late treatment of crowded first premolar extraction

cases:postretention evaluation of stability and relapse.AO

1998;68(1)61-68.

9.LORENZO FRANCHI,TIZIANO

BACCETTI,VERONICA GIUNTINI,CATERINA

MASUCCI, ANDREA VANGELISTI AND EFISIO

DEFRAIA:Outcomes of two phase orthodontic treatment of

deepbite malocclusions.AO 2011;81:945-952.

10.ADEBIMPE O.IBITAYO,VALMY PANGRAZIO-

KULBERSH,JEFF BERGER AND BURCU

BAYIRLI:Dentoskeletal effects of functional appliances

vs.bimaxillary surgery in hyperdivergent class2 patients.AO

2011;81:304-311.

11.J.F. CAMILLA TULLOCH,WILLIAM R. PROFFIT

AND CEIB PHILLIPS:Outcomes in a 2-phase randomized

clinical trial of early class2 treatment.AJODO 2004;125:657-

67.

12.S.JAY BOWMAN:One stages versus two stage

treatment:are two really necessary?AJODO 1998 VOL.113

NO.1.

13.NORMAN WAHL:Orthodontics in 3

millennia.chapter12:Two controversies:Early treatment and

occlusion.AJODO 2006;130:799-804.

14.JAMES R. WORTHAM,CALOGERO DOLCE,SUSAN

P. MCGORRAY,HUONG LE,GREGORY J.KING AND

TIMOTHY T. WHEELER:Comparsion of arch dimension

changes in 1phase vs 2phase treatment of class II

malocclusion.AJODO 2009;136;65-74.

15.TIZIANO BACCETTI,LORENZO

FRANCHI,VERONICA GIUNTINI,CATERINA

MASUCCI,ANDREA VANGELISTI AND EFISIO

DEFRAIA:Early versus late orthodontic treatment of

deepbite:a prospective clinical trial in growing

patients.AJODO 2012;142:75-82.

16.CARL DANN,CEIB PHILLIPS,HILIARY L.BRODER

AND CAMILLA TULLOCH:self-concept,class2

malocclusion and early treatment.AO 1995;65(6):411-416.

17.DAVID R.CHEN,SUSAN P.MCGORRAY,CALOGERO

DOLCE AND TIMOTHY T.WHEELER:effect of early

class2 treatment on the incidence of incisor trauma.AJODO

2011;140:E155-E160.


1 2 3Dr.Anjana.S, Dr. Sreelal.T, Dr. Shibu.A,4 5Dr Anuroopa.A, Dr Aparna Mohan

(1)Post Graduate (2) Professor and HOD (3&4) Reader (5) Senior lecturer

Sree Mookambika Institute of Dental Sciences

Introduction:

Minimum (or minimal) intervention dentistry can

be defined as a philosophy of professional care concerned

with the earliest detection and best possible cure of diseases

on micro molecular levels followed by minimally invasive

and patient friendly treatment to repair irreversible damage 1cause by such diseases. MID is a concept that embraces all

aspects of dentistry which aids in tissue preservation by

preventing disease from occurring and intercepting its

progress by removing and replacing it with as little tissue

loss as possible. Minimally invasive dentistry or

microdentistry forms a part of Minimum Intervention

Dentistry(MI)were the treatment procedure are minimally

invasive by nature.

Abstract

Key words

Minimally invasive dentistry is an advance in

science which is concerned with the ultra conservative

treatment of the infected and affected oral tissues.

Through an increasing range of relevant clinical

approaches , minimally invasive treatment preserves a

maximum amount of oral tissue and provides least

invasive intervention often regarded by patients as

painless and atraumatic Technological advances this

field makes minimally invasiveprosthodontics

appropriate solution for more and more cases.

Minimallyinvasive prosthodontics, Lumineers, laser,

flexible denture, naso alveolar moulding, shortened

dental arch It deals with the ultra-conservative treatment of 3

infected and affected oral tissue. It bridges the traditional

gap between prevention and surgical procedures. It can be

accomplished by using technology such as air abrasion,

l a se r s , DIAGNOden t , c a r i e s i nd i ca to r dye ,

transillumination, magnification, digital x-rays, implants,

Invisalign, apex locators, rotary endodontic instruments and

endoscopy as well as materials such as glass ionomer, bone

graft materials, bonding restoratives that make restorations 2

more predictable.

The three main components of minimally

invasive dentistry are(1) Dietary prevention , (2)Dental

prophylaxis and(3)Minimally invasive restorationswhich

has made enormous advancementsin adhesive and implant 5,6

dentistry. These changes have altered diagnosis, treatment

plan, and treatment options in clinical dentistry by forcing

clinicians to think in terms of conserving tooth structure,

vital tissues, and aesthetics.


Application Of Minimally Invasive Procedure In

Prosthodontics

Minimally invasive dentistry has a wide spread

applications in all branches of prosthodontics especially in

fixed and removable prosthodontics. In fixed prosthodontics it

is widely used in the preparation of laminate veneers, partial

veneer crowns, inlay retained bridges, resin bonded bridges,

ovate pontic, cantilever bridge, cordless retraction technique

and laser tooth preparation technique. Use of high torque hand

pieces also enables us to provide a minimally invasive

treatment procedure. In removable prosthodontics, flexible

denture, telescopic prosthesis and over denture follow the

principle of minimally invasive dentistry. Minimally invasive

procedure in implant prosthodontics is achieved through

Interactive CBCT, Flapless implant surgery; CAD CAM

guided surgery and Single stage implant. Resin infiltration

technique and laser technology has molded dentistry in to a

superspecialty which made the treatment procedures less

cumbersome and more comfortable for the patient. Splints,

palatal lift prosthesis and auxiliary prosthesis aids in less

invasive treatment procedure. Naso-alveolar molding and short

dental arch concept also is a part of minimally invasive

procedure in dentistry.

Removable Prosthodontics:

Telescopic-anchored prostheses are functionally

comparable with conventional fixed partial dentures, and are

considered to be a most effective replacement for lost teeth and

are well tolerated psychologically. Telescopic crowns have

been used mainly in RPDs to connect dentures to the remaining 15

dentition and as retainers in abutment- bone detachable

prostheses. Accordingly, detachable prostheses are usually

indicated only for patients with multiple abutments distributed

bilaterally in strategic positions along the dental arch. It is used

successfully in RPD as well as FPD supported endosseous 5

implants in combination with natural teeth, including 17, 18

overdentures. and also to splint periodontally compromised

dentition.

Flexible denture is also a minimally invasive

prosthesis that fulfills patient's needs because of its versatile

advantages which includes replacement of metal clasps with

colored clasps that blends with natural teeth and are more stain-

resistant than conventional acrylic prosthesis.

These dentures havegreater flexibility, can be

relined and when repaired does not warp. Theyare

aesthetically superior as well as comfortable for the patient.

Fixed Prosthodontics:

Preservation of Tooth Structure-The principles of crown

preparation described by Shillingburg determine the shape

and form of tooth preparations, which involves the concept

of minimally invasive procedure. Ideally a supra gingival

finish line should be given in posterior teeth and a sub

gingival finish line in anterior teeth which extend by 0.51

mm, not more than half the depth of the gingival sulcus to

ensure an intact epithelial attachment. Packing of

retraction cord in the gingival sulcus prior to preparing the

finish line will allow displacement of the gingival margin

for access and help minimize gingival trauma during .8, 9preparation

Exposure of a greater height of clinical crown

may involve either gingivectomy or flap surgery with

osseous recontouring. It is a means of enhancing retention, 10by increasing the clinical crown length of the tooth . Laser

will be the ideal treatment modality as it is minimally

invasive in nature.

With the advent of newer technology minimally

invasive procedures can be performed using hi- torque hand

pieces whichoffers the better torque and at lesser noise

level. Angular Hand piece designed for working on last 0molar 45 head angle for better accessibility favors to do a

conventional tooth preparation. Super torque cartridges

have an added advantage with better durability, reliability,

excellent performance and corrosion resistance

Laminate veneers are a thin layer of ceramic

bounded to the facial surface of minimally prepared

tooth. They are indicated for stained tooth that cannot

be bleached, to treat a traumatizedteeth and fractured

or worn out dentition .It can also be used for functional

c o r r e c t i o n s s u c h a s t o c o r r e c t c a n i n e

guidance,diastema or malformed teeth.Lumineers are

contact lens type of veneer without removal of tooth

structure. The teeth are moderately etched to prepare

for placement of veneers that makes it conservative in

nature.


Cantilever fixed partial dentures are FPDs with

only one side of the pontic is attached to the retainer.They

provide minimum tooth reduction as they use only one side

of the pontic as abutment.

Inlay retained bridges are indicated when teeth

with restorations are used as abutment in case of replacing

teeth in the premolar,molar region.They are less destructive

to toothstructure and the marginal finishing line easy to

clean.It is contra indicated when pontic span too large,in

patients with excessive para-functional habits, clinical

crown too short,weakend periodontium,occlusal

disturbances, in abutment teeth with tilting and in poor oral

hygiene.

Resin bonded fixed partial denture is a

conventional restoration which is indicated in the

replacement of teeth in the mandibular anterior region .Little

tooth structure has to be removed for this technique and most

of the preparation is made on enamel making it a minimally

invasive procedure. Resin cements are used in luting resin

bonded bridges. It provides a relatively simple option to

overcome the low tensile strength and poor adhesion quality

ofconventional cement. They have much higher tensile

strength and when used in combination with dentine bonding

agentsare less sensitive to repetitive dislodging forces.

Laser is an apt tool to execute minimally invasive

procedure as it produces less vibrations with minimum

audible drills, less micro-fractures, reduced discomfort to

patients and minimum need for local anesthetic.

Laser cavities facilitate good adaptation of composite to

enamel and dentin because of increase in the surface

roughness and openings of dentinal tubules. Gingival 13

Retraction using Lasers is less aggressive to the periodontal

tissues compared to the conventional ones.

Lasers may be used to perform pre-prosthetic surgeries like

hard and soft tissue tuberosity reduction ,torus removal

,treatment of unsuitable residual ridges including undercut

and irregularly resorbed ridges ,treatment of unsupported

soft tissues ,hyper plastic tissue, nicotinic stomatitis under

the palate of a full or partial denture, epuli, denture

stomatitis, and other problems associated with long-term

wear of ill-fitting dentures.

C l i n i c a l A p p l i c a t i o n s o f L a s e r s i n 12

FPDs includes LASER curettage in gingival sulcus prior

to tooth preparation to achieve good periodontal health and

thus esthetics. Low level laser therapy has a wide range of

application in prosthodontics which includes LILT (low

intensity laser treatment) tooth conditioning after tooth

preparation in vitalized teeth, HILT tooth decontamination/

preparation prior to definitive cementation of the porcelain

crowns , HILT laser curettage in the gingival sulcus every 3

to 6 months after final cementation of porcelain crowns and

laminate veneers and LILT gingival conditioning at follow

up.

Implant Prosthodontics:

Minimally invasive procedures in implantology is

accomplished with the aid of lasers for prosthetic hard

and soft tissue surgery, uncovering implants, correcting

soft tissue, treating periimplantitis and disinfecting 19implants. Single-stage implant placement surgery is

considered as a minimally invasive procedure as it is aless

time consuming technique with a greater comfort,

function and convenience. It offers a gain in comfort for

the patient by less traumatic technique and diminished

treatment period by avoiding the second stage surgery. 20

Flapless implant surgery uses a tissue punch technique

which makes the surgical field bloodless and also reduces

further bone loss. With the aid of computed tomography

(CT) a 3-dimensional (3-D) computer model was

fabricated followed by a Surgical Guide using a stereo-

lithographic technique.

Other minimally invasive procedures in Prosthodontics

include presurgicalnaso-alveolar molding, shorten dental

arch and resin infiltration technique. Presurgicalnaso-

alveolar molding is a minimally invasive procedure done

to correctcleft lip, alveolus and palate. It provides a

foundation for a less invasive surgical repair to restore the

normal anatomy in unilateral or bilateral cleft lip palate

patients. This approach allows for the controlled,

predicted repositioning of the alveolar segments without

the need for lip adhesion surgery

Shortened dental arch,(Fig-1) a current treatment concept is a recent minimally invasive dental procedure tailored to satisfy individual need and adaptive capability of the patient. In this concept the patient is restored with minimum number of teeth in the posterior region which would provide better comfort oral hygiene and reduced treatment cost.


Resin infiltration technique is the application

of resins on interproximal caries lesions has lead to the

development of new materials, which infiltrate and seal

the carious lesion, improving the inhibition of caries

progression. It is atreatment options for interproximal 14

caries by delaying the time point.

Conclusion:

Minimally invasive dentistry is a concept that

bridges the traditional gap between prevention and

surgical procedures. It is based ona large body of

scientific knowledgewhich promises further evolution

toward a more primary preventive approach, facilitated

by emerging technologies for diagnosis, prevention

and treatment.

References:

1) Yamaguchi K. · Miyazaki M. · Takamizawa T. · Inage H. · Kurokawa

H. Ultrasonic, Determination of the Effect of Casein Phosphopeptide-

Amorphous Calcium PhosphatePaste on the Demineralization of Bovine

DentinCaries Res 2007;41:204207

2) Joseph A. Whitehouse; Welcome to the world of Minimally

invasive dentistry .J MinimInterv Dent 2009; 2 (2)

3)Murdoch C A , Mc Lean M E Minimally invasive dentistry JADA, Vol

134, January 2003

4) Ericson What is minimally invasive dentistry?Oral Health Prev

Dent. 2004;2Suppl 1:287

5)Ardu S. Minimally invasive dentistry: A treatment philosophy.

PractProcedAesthet Dent 2008;20(7):426-427.

6)Novy BB, Fuller CE. The material science of minimally invasive

esthetic restorations.CompendContinEducDent 2008;29(6):338-347

7) F. M. BlairR. W. Wassell and J. G. Steele Crowns and other extra-

coronal restorations:Preparations for full veneer crowns British Dental

Journal Vol 192 No. 10 May 25 2002

8) Silness J. Periodontal conditions in patients treated withdental

bridges. II. The influence of full and partial crowns onplaque

accumulation, development of gingivitis and pocket formation. J Perio

Res 1970; 5: 219-224.

9). Silness J. Periodontal conditions in patients treated with dental

bridges. III. The relationship between the location of the crown margin and

the periodontal condition.. J Perio Res1970; 5: 225-229.

10)Smith D G. Toothwear: Crown lengthening procedures. In: Barnes I

E, Walls A W G, editors. Gerodontol pp.109-117. Oxford: Wright, 1994

11) Maiorana C. Lasers in the treatment of soft tissue lesions. J Oral

Laser Applications 2OO3; 3:7-14

12) Eduardo CP, The state of the Art of lasers in esthetic and

Prosthodontics. J Oral Laser Applications 2OO5; 5:135-143.

13)Gherlone EF et al. The use of 98O nm Diode and 1O64 nm Nd:YAG

lasers for gingival retraction in fixed prosthesis J Oral Laser

Applications 2OO4;4:183-19O.

14) Ho Phark, DDS; Sillas Duarte Jr, DDS, MS, PhD; Hendrik Meyer-

Lueckel, DDS, PhD,MPH; SebastianCaries Infiltration With Resins: A

Novel Treatment Option for Interproximal Caries DMG October 2009,

Volume 30, Issue 3

15) Langer A. Telescope retainers for removable partial dentures. J

Prosthet Dent 1981;45:37-43.

16) Langer A. Telescope retainers and their clinical application. J

Prosthet Dent 1980;44:516

17)Besimo C, Graber G. A new concept of overdentures with telescope

crowns onosseointegrated implants. Int J Periodontics Restorative Dent

1994;14:486-95.

18) Besimo C, Graber G, Schaffner T. Hybrid prosthetic implant

supported suprastructuresin edentulous mandible. Conus crowns and

shell-pinsystems on HA-Ti-Implants: part 2.Prosthetic construction

principles.ZWR 1991;100:70-

19)Esposito M, Grusovin MG, Chew YS, Coulthard P, Worthington HV.

. One-stage versus two-stage implant placement. A Cochrane

systematic review of randomized controlled clinical trials Eur J Oral

Implantol. 2009 Summer;2(2):91-9

20)Kusek ER. Use of the YSGG laser in dental implant surgery:

scientific rationale and case reports. Dent Today.2006; 25:98-103


1Dr. Sathya Chandran,

2Dr.Ramachandra Prabakar,

3Dr.Saravanan,

4Dr.Karthikeyan,5 Dr.Raj Vikram,6 Dr. Eshwara prasath

Introduction:The advancement in technology and innovations of

imaging systems for orthodontic practice require a

continuous update of their applications and assessments

of their strength and weakness, as well as guidelines for

utilization. Orthodontists are challenged by the

increasing number and complexity of these systems and

softwares. Accurate diagnostic imaging is an essential

requirement for the optimal diagnosis and treatment 1

planning of orthodontic patients . In addition, it is a

critical tool that allows the clinician to monitor and

document the treatment progress and outcome. The

purpose of this article is to update orthodontists about the

current options and applications of the latest imaging

techniques in orthodontic practice and to review the 5existing software advances .

Materials & Methods:

The authors reviewed the limitations of 2 dimensional

imaging over the 3 dimensional computed tomography 9

which is cone beamed . The Cone Beam Computed

Tomography (CBCT) has contributed in diagnosis and

profound understanding of diagnosis to development of

more efficient biomechanical treatment approaches and

biological considerations.

3D Dimensiondiagnostic aid

nd(1&6) 2 year postgraduate, (2)Dean and HOD, (3& 4) Professor, (5) Reader, Department of orthodontics, Thai Moogambigai Dental College.

Abstract

Key words

Cone Beam Computed Tomography

(CBCT) is a revolutionary diagnostic aid in

orthodontics used at present. Aim of this paper is to

emphasize the process and the significance of CBCT

in orthodontics in various treatment modalities

which overcomes the 2 dimensional conventional

method of radiography used to 3 dimensional

imaging.

Cone beam computed tomography, tmj disorder,

orthodontic implants, impacted teeth.

The cone-beam computed tomography (CBCT)

scanners were introduced in the late 1990s. Shortly after, the

US Food and Drug Administration (FDA) approved the first 5CBCT unit in 2001 . Since then, there has been an enormous

interest in this new technology for its clinical and research

applications. The CBCT is an imaging acquisition technique

that utilizes a volumetric scanning machine. This

technology uses a cone-shaped X-ray beam directed

towards a flat two-dimensional (2D) detector. When both

rotate around the patient's head, a series of 2D images are

generated. The software then reconstructs the images into

three-dimensional (3D) data set using a specialized 5, 10, 4.

algorithm .

Currently, there are more than 4 CBCT systems

from 20 different companies available commercially. The

commonly used CBCT imaging acquisition systems are the

3D Accuitomo (J. Morita, Kyoto, Japan), CB MercuRay

(Hitachi Medical Corporation, Osaka, Japan), iCAT

(Imaging Sciences International, Hatfield, PA), Galileos

(Sirona Dental Systems LLC, Charlotte, NC), New-Tom 3G

(QR srl, Verona, Italy), Scanora 3D (SOREDEX,

Milwaukee, WI), and Kodak 9500 (Kodak Dental Systems, 5, 10

Rochester, NY) . There are large variations in the quality

and characteristics of the images or the reconstructed

volumes and the radiation doses between most of these

CBCT systems. Machines with reduced radiation doses and

less powerful tubes are often associated with poor image

quality, low contrast resolution and increased noise. The

exposure parameters, the source-detector distance, the field

of view (FOV), the data reconstruction algorithm, and the

software used are among the major factors responsible for 5those variations . The currently available CBCT units utilize

radiation doses ranging from 87 to 206 ìSv for a full 11craniofacial scan . These radiation doses are slightly higher

than the conventional radiographic techniques such as the

lateral cephalograms or the panoramic radiographs and

markedly lower than that of multi-slice CT. The scan time

varies between 10 to 75 seconds, depending on the FOV and 13

the CBCT unit used .

CBCT in orthodontics


Fig 2 :A shows the pre object apparatus of x-ray source path of rotation

and object, 2B shows the image area detector with x-ray beams in shape of 4cone .

Discussion:

Craniofacial imaging is a crucial content of an

orthodontic patient's record. The gold standard for

orthodontic patient's records is the efficiency to

achieve an accurate replication of the real 10

anatomical structures or the “anatomic truth” .

Although at present the use of the traditional

imaging in orthodontics has been adequate, the

achievement of the ideal imaging goal of

replicating the anatomic truth has been limited by

the traditional technology such as the 2D frontal

and lateral cephalograms, panoramic radiographs, 9and intraoral/extraoral photographs . Recently,

higher emphasis has been placed on the CBCT

technology, the 3D images, and virtual models.

The main advantage for the use of CBCT is that the

clinician can get more accurate data from single

scan than from the many 2D radiographs 9

traditionally used, with less radiation exposure .

Fig 1: the picture shows all 360 slices at a

single shot ,

The 3D CBCT data can greatly expand the orthodontist's

diagnostic capabilities. It offers a comprehensive evaluation of the

dentition and is very useful for identifying abnormalities such as

missing teeth, supernumerary teeth, eruption disturbances, teeth

malpositions, and/or root irregularities that could delay or prevent 4, 6, 7tooth movement . CBCT can be considered the technique of

8choice for examining and pin-pointing the impacted teeth . The

exact position of impacted tooth and its relations to the adjacent

roots or important anatomical structures such as the maxillary sinus

or the mandibular canal when planning surgical exposure and

subsequently orthodontic management can be precisely assessed by 8,7,2

3D CBCT .

Using CBCT scans, alveolar bone can be accessed from all

aspects not only on the mesial and distal surfaces of the tooth. This

allows for the assessment of the width of available bone for

buccolingual movement of teeth during orthodontic management

especially in cases requiring arch expansion or labial movement of 6

incisors . Fenestrations, dehiscence, and/or external apical root 7

resorption can be precisely visualized on the 3D images .

Evaluation of alveolar bone volume, which is especially important

in periodontally compromised adult orthodontic patients, is one of

the beneficial uses of CBCT in orthodontics. The width of alveolar

ridges for placement of implants is another variable that can be 6, 2investigated using CBCT .

Temporomandibular joint (TMJ) disorders with 11Orthodontic patients are common . During period of

development, the disorders may alter the facial growth pattern and

may also affect the growth of the ipsilateral part of the mandible

with compromisation in the maxilla, tooth position, occlusion, and

cranial base. CBCT allows the orthodontists to assess and quantify

these changes associated with TMJ disorders more accurately than

the 2D images as these changes occur in the vertical, horizontal, 11, 12

and transverse directions .


Fig 2: shows the malposition of a 13 yr old patient due to odontoma in relation to

11 causing impaction of permanent teeth diagnosed by 3D CBCT.

CBCT is especially indicated when

more information about the morphology

and internal structure of the bony

components of the TMJ is in need. Studies

have shown that CBCT images provide

higher reliability and accuracy than CT and

panoramic radiographs in the detection of 11, 12, 13condylar cortical erosion . CBCT

images also allow for the visualization of

the TMJs from different views and efficient

evaluation of its relationship to the

dentition and Occlusion.

Fig 3: 3D CBCT volume allows for better visualization and provides more

details about the morphology and position of the TMJ and the condyles from

different views. In addition, the TMJ cross-section view permits complete and

thorough examination of the joint through a group of cross section slices.

P r e o p e r a t i v e i m p l a n t s i t e

assessment is probably one of the most

usefu l appl ica t ions of CBCT in

orthodontics. In the orthodontic field,

osseointegrated implants are either used for

anchorage or as a prosthetic replacement of

missing teeth. The accurate determination

of root angulations and the available space

are essential for successful placement of the 6, 4implant . CBCT can be used to accurately

assess the space availability and root

angulations as well as the 3D quantification

of the alveolar bone at the implant site.

Conclusion: In orthodontics, the application of

CBCT technique has made a remarkable

breakthrough in diagnosis and the treatment

plan by giving the orthodontists inspiration

to do better of what they do the best.

However the hunt for further advanced

diagnostic aids is evidenced in recent years

like of how 2D imaging is replaced by 3D

imaging due to the advantages and

disadvantages in detecting the exact

location of supernumerary and impacted

teeth and in appropriate treatment 12, 13

planning . Likewise, advantages and

disadvantages of CBCT must be considered

together, and only when more information

is in need, the use of this technique is

suggested. Its unnecessary prescription

should otherwise be avoided.


Fig 4:Axial and sagittal sections showing the buccal and lingual bone thickness, as wel l as the rela t ionship between the implant and the infer ior a lveolar nerve (labeled in red color).The 3D view is important in the e v a l u a t i o n o f s p a c e availability.

References: 1.Dan Grauera; Lucia S.H. Cevidanes; Martin A.Styner ; Inam

Heulfed;Eric T.Harmon ; Hongtu Zhuf; William R.Proffit :Accuracy and

Landmark Error Calculation Using Cone-Beam Computed

TomographyGenera ted Cepha lograms , (Angle Or thod .

2010;80:286294.)

2.Snehlata Oberoi, DDS, MDS, Associate Professor of Clinical Orofacial

Sciences, Center for Craniofacial Anomalies, Department of Orofacial

Sciences, School of Dentistry, University of California at San Francisco,

San Francisco, California: CBCT Evaluation of Impacted Canines and

Root Resorption, P C S O B u l l e t i n november 2 0 1 1

3.Patil NA,Gadda R, Salvi R, Cone beam Computed Tomography A

Third Dimension, J Contemp Dent 2012; 2(3): 84-88.

4.Xubair,Graber,Vanarsdall,Vig;Orthodontics - Current Principles and

Techniques - Graber 5th edition 2011

5.Ahmed Ghoneima1,2, Eman Allam1, Katherine Kula1 and L. Jack

Windsor1: Chap 8-Three-Dimensional Imaging and Software Advances

in Orthodontics , Orthodontics - Basic Aspects and Clinical

Considerations March, 2012

6.Kee-Joon Lee, Euk Joo, Kee-Deog Kim, Jong-Suk Lee, Young-Chel

Park, and Hyung-Seog Yuf, : Computed tomographic analysis of tooth-

bearing alveolar bone for orthodontic miniscrew placement, (Am J

Orthod Dentofacial Orthop 2009;135:486-94)

7.Hongyu Ren; Jun Chen; Feng Deng; Leilei Zheng; Xiong Liu; Yanling

Dong:Comparison of cone-beam computed tomography and periapical

radiography for detecting simulated apical root resorption, ( A n g l e

Orthod. 2013;83:189195.

8.Hossein Nematolahi,Hamed Abadi,Zahra Mohammadzade,Mostafa

Soofiani Ghadim: The Use of Cone Beam Computed Tomography

(CBCT) to Determine Supernumerary and Impacted Teeth Position in

Pediatric Patients: A Case Report ,J Dent Res Dent Clin Dent Prospect

2013;7(1):47-50 | doi: 10.5681/joddd.2013.008

9. Adams, G., Gansky, S., Miller, A., Harell, W. & Hatcher D.

(2004). Comparison between traditional 2-dimensional

cephalometry and a 3-dimensional approach on human dry

skull. Am J Orthod Dentofac Orthop 126:397-409.

10. Cevidanes, L., Oliveira, A., Grauer, D., Styner, M. & Proffit,

W. (2011). Clinical application of 3D imaging for assessment

of treatment outcomes. Semin Orthod 17:72-80.

11. Hilgers, M., Scarfe, S. & Scheetz, J. (2005). Accuracy of

linear temporomandibular joint measurements with cone

beam computed tomography and digital cephalometric

radiography. Am J Orthod Dentofacial Orthop 128:803-811.

12. Kumar, V., Ludlow, J., Cevidanes, L. & Mol, A. (2008). In

vivo comparison of conventional and cone beam CT

synthesized cephalograms. Angle Orthodontist 78: 873879

13. Swennen, G. & Schutyser, F. (2006). Three-dimensional

cephalometry: spiral multi-slice vs cone-beam computed

tomography. Am J Orthod Dentofac Orthop 130: 410416


1 2A. Leoney P. S.Manoharan1 2Reader, Professor, Department of Prosthodontics, Rajah Muthiah Dental College,Chidambaram

Porcelain laminates have been used over the past 25 years with many of its own limitations and drawbacks. Failure due to de-bonding has been found as one of the prime drawbacks. Occlusion, preparation design, choice of bonding agents has been listed as other

1,2co-variables . Recently, evidence based dentistry has narrowed down the major cause of such failures to be “selection of the case”. Other reasons for failure can be discoloration, which may be due to poor color stability of the resin used for cementation. With advancements of laboratory technology and simplification of technique and material use, porcelain laminates have found its place in general practice. Thus, it becomes mandatory for the restoring dentist to anticipate various predicaments during the treatment phase. Presented below, is a case report of an esthetic rehabilitation with smile design of a patient, with special thrust on the problem areas and possible suggestions and tips to avoid them

a problem based treatment approach

Abstract

Key words

Porcelain Laminates

Porcelain laminates have been used for over the past

25 years, with many of its own limitations and

drawbacks. Evidence based dentistry has narrowed

down the key to success for such a restoration to

“selection of the case”. With the advancement of

laboratory support and simplification of techniques

and material use, porcelain laminates have found its

place in general practice. This paper is a case report,

which outlines the treatment approach with

porcelain laminates, with special emphasis on

problem areas. It also provides simple tips and

solutions to the readers to avoid or overcome

biological, mechanical or esthetic predicaments

associated with such restorations.

Porcelain laminates, Diagnostic wax up, Smile design, etc.

Introduction

Case report:

History and examination: A 19 year old female,

reported to the dental office, requiring correction of

discolored maxillary and mandibular teeth. History

and examination revealed discolored direct

composite restorations in relation to the upper

anteriors, which was done elsewhere, more than a

year back (Fig.1a and 1b).

Further intra-oral examination revealed improper

contacts and contours of composite restorations from

maxillary second premolar to premolar, with crazing

and significant surface and marginal discoloration.

The remaining teeth were also discolored possibly

due to fluorosis which was suggestive through her

history.

Diagnostic work up: When one is considering a

cosmetic treatment option such as veneers, it is

especially important to follow this logical sequence of

events.

Fig.1-a

Fig.1-b


Diagnostic wax up was carried out with green inlay

wax and the esthetic outcome was explained to the patient.

The anticipated smile line was scribed on the lower anterior

teeth for reference later. Two Putty indices were made

which included full arch index as well as an horizontally cut

index (Fig.5) were fabricated to guide the incisal and labial

clearance during tooth preparation.

Diagnostic casts (Fig.2) were made and evaluated on a semi-adjustable articulator [Artex Kirback] (Fig.3) with face-bow transfer. Duplicate casts were made so that a diagnostic wax-up (Fig.4) can be created. The maxillary and mandibular teeth had Class II div 1 malocclusion, with labial positioning of both maxillary canines with moderate rotation on the right side. Arch tooth size and available space was measured as it would help us to plan the diagnostic wax up and further treatment. Various treatment options were suggested to the patient, viz., crowns, laminates and indirect composites. Porcelain laminates [IPS emax Press] was opted by the patient after evaluating the advantages, disadvantages of each treatment and associated treatment charges.

Clinical procedure: Systematic step by step management

work up was planned. As the young lady had a history of

rheumatic heart disease, she was referred to a physician to

obtain opinion regarding the use of antibiotic prophylaxis

and local anesthetic during the procedure.

Tooth preparation was carried out in a single sitting for all

the maxillary anterior teeth including the first premolars on

both sides following local anesthetic infiltration. Basic

tooth preparation principles were carried out with sub-

gingival margins and palatal overlap of 2mm from the

incisal edge. Labial/incisal clearance was checked with the

indices which were fabricated from the diagnostic wax up,

the use of which was very crucial when the preparation of

the rotated and malposed canines were carried out. The

margins were placed away from the centric contact and free

of protrusive interferences. Contact points are relieved by

proximal strips indicated by (Fig.6) and final finishing is

done with smooth diamond points. Care is taken to limit the

preparation to only the enamel so that the luting agent used,

can bond better with enamel and retention is superior than

when placed in dentin. [3] The rotated canine posed little

difficulty in limiting the preparation to enamel. So,

additional dentin was removed with the consent of the

patient, so that adequate clearance can be obtained for

esthetic restoration (Fig.6). Depth orientation burs were

used and principles of tooth preparation were faithfully 4,5,6followed . Isolation is crucial for margin capture during

impression making. Poly-vinyl-siloxane was used with

putty-wash reline technique in a stock tray after performing

gingival displacement with retraction cords.

Fig.2 Fig.3

Fig.4

Fig.5


Provisional were fabricated with acrylic resin

using the putty indices as guide for contours and were

temporarily cemented. The provisional restorations were

adjusted, so that a rough appraisal of treatment outcome

can beperceived both by the patient and the dentist. While

selecting the shade a lighter shade was selected for the

patient taking into all the standard parameters into

consideration viz., skin color, sclera color and patient 7

preference .

Laboratory procedure: Casts were poured with type IV

dental stone and removable dies were prepared. Individual

wax patterns for the respective laminates were fabricated in

the lab using pressable ceramic [IPS e max press] and

staining was carried out according to the selected shade.

Smile design is an often discussed topic in anterior esthetic

rehabilitation. Though the literature gives us a plethora of 4,8dimensions in smile designing , the practical application is

incorporating them systematically. A simple smile design

chart(Table .1) as mentioned above would help the operator

to carry out a comprehensive esthetic work up for anterior

restorations.

Smile re-designing or re-establishing the original

smile is purely based on the patients' decision after

explaining the anatomic and functional limitations. These

limitations like tooth structure available, exposure of gums,

space available, inclination/ rotation of natural teeth, over-

jet/over-bite and forces exerted on the restoration can restrain

the patients' option on retaining the original smile.

Smile parameter Assessment Suggestions for work up Visibility 2mm of visibility of Smile curve transferred to the cast on the lower anterior teeth all anterior teeth Shade Lighter than the Staining can be done after try-in proposed shade Contours Reproduce the lost Modifications if any should be done with maintenance of contours embrasure and self-cleansing surfaces Width of teeth Golden proportion, Space analysis Tooth size, arch length discrepancy alignment Face Form / contours Esthetic build up [Dentist- technician communication] profile/ symmetry Shade selection Compare with color Should complement the selected shade of skin and sclera

Table no. 1: SMILE DESIGN WORK SHEET

Fig .6

Form a convex smile Curve

Follow the lower lip countour ( diagnostic casts &Provisionals),incisal embrasures created with balance of negative space and sex of the patient

Incisal edges


Optical illusion is a physical property of light reflection

and perception, which can be exploited in designing the

contours of the restoration. The labio-proximal line

angle can be brought closer to the midline of the tooth or

away near the proximal surfaces (Fig.8) depending on

whether to narrow or broaden the appearance of the

restoration, though the space available is a fixed

determinant. Longitudinal or horizontal grooves can be

created to give narrow or a broad dimension to the tooth.

Stains near the proximal surfaces also give an illusion of

narrow teeth. Incisal embrasures(Fig.8)augments the

esthetics.

Try-in and delivery of Laminates: During try-in

composite resin was used to hold the laminates in place

and adjustments were carried out which included

contacts, labial/palatal/ proximal contours, margins.

Shade modification and characterization if any, were

noted and then communicated to the laboratory for further

refinement and final glazing. The laminates were

cemented after the application of primer (Monobond S,

ivoclar vivadent, Liechtenstein), bonding agent and dual-

cured composite luting resin cement (N variolink ivoclar

vivadent, Liechtenstein ). Isolation was carried out in

perfection during the entire procedure so that it would

eliminate any contamination which would affect 9bonding . Postoperative photographs (frontal, lateral and

occlusal photographs) were taken and compared with

preoperative photographs and discussed the positives of

the treatment procedure. Patient's perception and

feedback of the laminate treatment was found to very

satisfactory (Fig 9).Patient was instructed to cleanse

inter-dental areas and avoid excessive consumption of

staining beverages or carbonated drinks to prolong the

durability of the restoration. Periodic recall would enable

the patient to be seen by the treatment provider and

documentation of follow up of restorations.

Fig 8:

Schematic illustration of factors affecting the restoration

Fig. 9

Fig. 10

Fig. 7


Once the case is selected, the treatment plan should be

outlined based on the above mentioned diagnostic criteria.

Diagnostic casts with face-bow transfer will provide the

dentist information regarding the esthetic plane, alignment,

occlusion and space availability vs. space needed. It also can

be used to do a mock preparation and perform an esthetic wax

build-up [ivory wax is preferred though blue inlay wax is

used in this case]. This diagnostic wax-up can be used to

fabricate putty indices as shown in the figure for clearance

assessment during tooth reductionand also to provide an idea

of treatment outcome to both the patient and the restoring 10,11

dentist . In this case this step has played a major role, as it

simplified the difficulties that could arise in the tooth

preparation because of alignment problems such as rotations

and labial placement of canines.The mal-aligned canines

were given an esthetic facelift (Fig.9).Location of margins of

the preparations, centric/proximal contacts and incisal

guidance is also visualized in this procedure.

DISCUSSION:

Anterior esthetic rehabilitation has always been a

challenge for the restoring dentist as these restorations are

subjected to the critical review of the observers starting from

the layman to the fellow dentist. More than the visual appeal

which these restorations can contribute, they also should be

biologically compatible, functionally harmonious and last

for a considerable period of time without any mechanical

failure. These are basic objectives that should be achieved for

any restoration and replacement. As discussed above,

'selection of the case' is crucial, while rehabilitating with

restorations suchas porcelain laminates. Some common

diagnostic key factors which would affect the prognosis and

acceptance of treatment are listed.An individual with a

traumatic bite/para-functional habits may not be able to

sustain such restorations. In the same way, a consumer of

acidic beverages may increase the risk of failure due to

erosion of enamel and subsequent failure of bonding by the

resin. A steep incisal guidance which needs rehabilitation can

also suggest a limitation for such restorations.

Tooth reduction is restricted to enamel and 0.7 to

0.8mm of labial reduction was achieved in this case by

the special three wheel diamond. Preparations extending

to dentin can reduce the bond strength between the resin

and the laminate. According to a study by Piemjai M and

12Arksornukit M bonding techniques and curing systems

of resin cements influenced the fracture resistance of

porcelain laminates. Dry bonding with auto-

polymerization resin provided the highest fracture

resistance of porcelain. Porcelain bonded to enamel with

this resin had much higher fracture strength than when

bonded to dentin. Incisal reduction of 1.2mm was carried

out with palatal extension of 1.5mm. This was decided in

the wax-up stage based on centric contacts and incisal

guidance. Though supra-gingival margins would suffice

for such esthetic porcelain laminates, a sub-gingival

margin with radial shoulder, was provided in this case as

the tooth was discolored (Fig 10).

Fig. 11


The consistency of the luting agent, pressure

exerted during cementation and the film thickness of the

luting agent may affect the luting composite thicknessUse of

desensitizing agents to alleviate the postoperative sensitivity

have been advised by some authors when dentin is exposed

16,17,18or near exposure after tooth preparation . However, it

was found that retention of crowns and laminates have been

19,20considerably reduced by their application . In veneer

preparations, the clinician is advised to limit the preparation

only to enamel, use adequate water coolant during

preparation to reduce the postoperative sensitivity. In the

case discussed above, except the canine, other preparations

were well within the enamel. Mild postoperative discomfort

in the form of sensitivity was reported by the patient for two

days following luting the restoration, which subsided

without any intervention.

During the fabrication of laminates a carefully devised

dentist-technician communication chart would reduce the

repetitions of laboratory work after try-in procedure. This

should include the specifications required by the dentist

based on the treatment planning in smile design. Regardless

of the color, shape or attention to detail, there must be

sufficient time to adequately finish all restorations. Both

esthetics and function can best be satisfied when the

restoration acquires its maximal finish as seen in (Fig.9,11

and 12). In the final analysis, the restoration will look better

for a longer period of time. Life expectancy of the restoration

may, in fact, be directly dependent on just how well this task

21is accomplished . It has been said that treatment is never

successful unless the patient is satisfied in terms of comfort,

esthetics and functions like chewing. Problems may arise

from patients who hold what most people consider

unrealistic expectations, most commonly with respect to the

. esthetic outcome This can be avoided by a systematic work

up, which includes the history, realizing patient's demands

and expectations, thorough dentist- patient communication

along with diagnostic wax ups and temporaries.

Patients and dentists may have conflicting

opinions regarding the definition of an esthetically

pleasing smile. Everydentist is likely to encounter

malcontent patients who may have difficulty

communicating their esthetic desires for smiles

andmay even refuse to pay for successful treatment

outcomes that they misperceive as failures. Learning

how to work with suchpatients is essential. Part of

achieving patient satisfaction is encouraging their

participation in designing their smile. With the useof

such a restoration an exacting acrylic/wax smile

would be required for the patient to anticipate the

13result .

Shade selection is carried out with standard

shade guide taking into consideration the general color

of the skin and sclera. In such cases where the entire

anterior segment is to be restored, the clinical

judgment of the dentist would determine the esthetic

outcome. Discussion with the patient and the patient's

relatives about the shade preference will help the

dentist in the decision making. Documentation of

pretreatment and post treatment photographs taken

with standard lighting and distance with the patients

lips at rest and during active smile would help the

patient to compare appreciate the treatment outcome.

Ideally, a porcelain veneer can mask completely the

underlying discolored tooth substance with minimal

reduction of sound tooth substance (0.30.7 mm for the

labial surface and 0.51.0 mm for the incisal edge). The

veneer's color, however, can be affected by the

underlying discoloration. However, severe

discolorations can be masked by high density alumina 14

core veneers .

Ceramic to luting agent thickness ratio can

contribute to mechanical failure. A sufficient and even

thickness of ceramic combined with a minimal

thickness of luting composite will provide the 15

restoration a thickness ratio above 3 .


CONCLUSION:

A case of anterior esthetic rehabilitation with

porcelain laminates was discussed, taking into

consideration the biological, mechanical, esthetic

and functional demands. A sound knowledge of the

basics with the skill of the dental technician would

pave way for the path of success in any restoration.

When it comes to esthetics, an extra mile has to be

tread by the dentist to imbibe the dimensions of

beauty and harmony and apply them to the

restorations in his practice.

Fig.12

REFERENCES:

1. Peumans M, De Munck J, Fieuws S, Lambrechts P,

Vanherle G, Van Meerbeek B. A prospective ten-year clinical

trial of porcelain veneer: J Adhes Dent. 2004 Spring;6 (1):65-

76.

2. Heather J. Conrad, Wook-Jin Seong, Igor J. Pesun :Current

ceramic Materials and systems with clinical recommendations:

A systematic review: J Prosthet Dent 2007;98:389-404.

3. Exner HV. . Predictability of color matching and the

possibilities for enhancement of ceramic laminate veneers: J

Prosthet Dent. 1991 May;65(5):619-22.

4. Magne P, Belser UC.Novel porcelain laminate preparation

approach driven by a diagnostic mock-up: J Esthet Restor Dent.

2004;16(1):7-16

5. Goldstein RE. Finishing of composites and laminates:

Dent Clin North Am. 1989 Apr;33(2):305-18, 210-9.

6. Lu bocovich. Smile designing for the malcontent patient:

Compend Contin Educ Dent. 2010 Jul-Aug;31(6):412-6.

7. Piemjai M, Arksornnukit M. Compressive fracture resistance

of porcelain laminates bonded to enamel or dentin with four

adhesive systems: J Prosthodont. 2007 Nov-Dec;16(6):457-64.

8. Horn HR, Porcelain laminate veneers bonded to etched

enamel: Dent clin north AM, 1983: 27: 6671-84.

9. Quinn F Mcconnell RJ, Birne D. Porcelain laminates: A

review: Br. Dent. J, 1986; 161: 61-65.

10. Robbins JW, Colour chracterisation of porcelain veneers:

Quintessence int, 1991; 22: 853-56.

11. Christensen GJ.. Resin cements and postoperative

sensitivity: J Am Dent Assoc. 2000 Aug;131(8):1197-9.

12. Cherukara GP, Davis GR, Seymour KG, Zou L,

Samarawickrama DY. Dentin exposure in tooth preparations for

porcelain veneers: a pilot study: J Prosthet Dent. 2005

Nov;94(5):414-20.

13. Matsumura H, Aida Y, Ishikawa Y, Tanoue N.Porcelain.

Laminate veneer restorations bonded with a three-liquidsilane

bonding agent and a dual-activated luting composite: J Oral Sci.

2006 Dec;48(4):261-6.

14. Reshad M, Cascione D, Magne P. Diagnostic mock-ups as an

objective tool for predictable outcomes with porcelain laminate

veneers in esthetically demanding patients: a clinical report.

Reshad M, Cascione D, Magne P. J Prosthet Dent. 2008

May;99(5):333-9

15. Chu FC. Clinical considerations in managing severe tooth

discoloration with porcelain veneers: J Am Dent Assoc. 2009

Apr;140(4):442-6.

16. Rosenstiel SF, Land MF, Fujimoto J. Contemporary fixed thProsthodontics. Elsevier publication, 4 edition.

17. Shillingburg HT, Sumiya Hobo, Lowell D. Whitsett,

Richard Jacobi, Susan E. Brackett. Fundamentals of Fixed rdProsthodontics. Quintessence books, 3 edition.

rd18. Ronald E. Goldstein. Change your smile. 3 edition

Quintessence books.

19. Magne P, Kwon KR, Belser UC, Hodges JS, Douglas WH.

Crack propensity of porcelain laminate veneers: A simulated

operatory evaluation: J Prosthet Dent. 1999 Mar;81(3):327-34.

20. Weinberg LA. N Y State Dent J. Tooth preparation for

porcelain laminates: Dent Clin North Am. 1989 Apr;33(2):305-

18, 210-9.

21. Quinn F, McConnell RJ, Byrne D. Porcelain laminates: A

review. Br Dent J. 1986 Jul 19;161(2):61-5.


1 2 3 Dr.Gajendra.V, Dr.Hema.G, Dr.Kathiga Kannan,1&2 3Reader, Professor & Head,Departmentt of Oral Medicine & Radiology,SMIDS,Kulashekaram, TamilNadu.

GENE THERAPY IN OROMUCOSAL LESIONS:

Gene therapy is considered to be one of the most

exciting areas of medicine for the future. It aims to correct

the underlying genetic defects in human disease rather 1

than just focusing on symptoms .

Gene therapy is the introduction and expression

of recombinant genes in somatic cells for the purpose of 2

treating disease .Initially, gene therapy was associated

with either the correction of inherited genetic disorders or 3treatment of life threatening conditions . Currently, gene

therapy protocols has been approved in humans for

experimental studies with severe combined

immunodeficiency (SCID), cystic fibrosis, AIDS,

ma l ignan t me lanoma, va r ious ca rc inomas , 4hypercholesterolemia and brain tumors.

In gene therapy, the new genetic information uses

the host cells machinery to express its encoded gene

product. In this sense, DNA is being used like any 2

pharmacological agents to induce therapeutic effects .

In DNA therapy drug delivery is simplified; we

need only one delivery system capable of inserting new

DNA. In addition, this form of therapy offers a new

approach for disease therapeutics by providing a

potentially permanent treatment by targeting delivery of

genes into the genome of stem cells. In this way, the

transgene will be inherited by stem cell progeny, and

therapy will be sustained after administration of a single

gene dose. Finally it may be possible to localize

expression of a therapeutic gene by delivering genes to

particular cells or by using tissue or cell specific 2promoters to limit expression to cells of interest .

Epidermal and oral keratinocytes are potential

vehicles for gene therapy. Several featuresof these

tissues can be utilized to achieve delivery of therapeutic

gene products for local or systemic delivery. These

qualities include 1) presence of stem cells 2) the cell,strata

and site specfic regulation of keratinocyte gene

expression 3) tissue accessibility 4)secretory capacity 5)

tissue culture models simulate invivo epithelium 6) 2

grafting techniques available 7) inherent safety features.

In addition oral diseases are difficult to treat with

conventional, topical drug application, since saliva tends

to dilute topical agent. Direct delivery of genes into the

surface epithelium would circumvent such difficulties in 2

drug delivery .Gene therapy, thus holds a bigger promise

for disease therapeutics in the near future.

in oral diseases An over view

Gene Transfer:

Clinical use of gene transfer can be accomplished in either

of two ways.

Completely invivo, when the foreign gene is

administered to the patient's by viral or physical methods.

Exvivo, when the foreign gene is applied to certain

of the patient's cell that are temporarily maintained outside

of the body in a sterile environment and after a suitable 1

period, returned to host .

Gene transfer can be used clinically for two purposes ;

Gene therapy, it can be defined as the gene transfer

for the purpose of the treating human disease, this includes

the transfer a new genetic material as well as the

manipulation of existing genetic material. This holds true

especially for cancer cells, where dominantly activated

oncogenes are targeted.

Gene therapeutics the use of gene transfer to

produce biomolecules with pharmacological functions.

Gene therapeutics could be employed for either treatment or 1

prophylactic purposes .

Genetic material can be transferred via a vector,

vector is defined as the vehicle that is used to deliver the

gene of interest.

Ideal features of vector include it should target

specific tissues or organs, necessity to maintain prolonged

expression of transgene, the possibility of engineering cells

invitro and then re-implanting them, potential side effects

on the host such as toxicity and immunization must be 1prevented .

Vectors can be viral on non viral. viruses are the

closest delivery vehicle to this ideal vector. By removing the

virulent genes from a virus and substituting the therapeutic

gene, we can create a tamed virus that can be used as a safe

delivery vehicle. Therefore altered viruses have become the

most commonly used gene therapy vectors in clinical trials.

Commonly used virus vectors are retrovirus, adenovirus, 2

adeno-associated virus .

Nonviral methods include physical methods such

as electroporation, microinjection, gene gun and chemical

methods include cations and polycations, lipid vectors,

cationic lipid vectors. Advantages of these nonviral vectors

are it has no replication risk, transfect both dividing and

nondividing cells, less immunogenecity.Disadvantage in 2

limited transfection .

Gene therapy


GENE THERAPY IN OROMUCOSAL LESIONS:

Three groups in oral diseases that are actively using

this science, all for quite different purposes with different

approaches these include

1)Gene transfer to salivary glands

2)Gene transfer to oromucosal keratinocytes

3)Gene therapy to oral cancer

Gene transfer to salivary glands:

Salivary glands present an inviting target for invivo

gene transfer because of other anatomic location and ease of

access.

Studies were aimed at repair of salivary glands whose

acinar cells have been irreversibly damaged. The two common

situations that result in acinar cell damage, and thus inability of

glands to secrete fluid, are therapeutic radiation (for head and

neck tumors with salivary glands in radiation field) and

Sjogren's syndrome. The aim of the study was to convert

surviving ductal cells into acinar like cells that secrete salt and

fluid. This is an example of what is termed organ engineering,

changing the basic function of a cell type and efforts was also

directed at creating a recombinant adenovirus that contains a

water channel gene.

Gene therapeutics:

The approach here is to use normally functioning

sal ivary glands to del iver in their secret ions,

biopharmaceuticals encoded by transferred foreign gene.

Researchers hypothesized that over expression of

naturally occurring salivary anticandidal peptide (histatin) has

the possibility of treating, or even preventing the severe

mucosal (oral-pharyngeal-oesophageal) candidiasis that

accompanies immunosuppression due to infection (as in

AIDS) or to therapeutic treatment (for ex, as a result of

transplants).

Another example, investigators have isolated gene for

fimbrillin, a surface protein of the important periodontopathic

bacterium porphyromonas gingivalis. Their aim is to construct

a recombinant adenovirus containing this gene and transfer it

to salivary glands. They anticipated that the soluble protein

product of this gene will be secreted locally around the gland as

well as in saliva. They expected that locally secreted fimbrillin

to elicit an immune response leading to production of secretory

IgA. This secretory IgA would be secreted in saliva and

neutralize p. gingivalis inhibiting its ability to participate in

plaque formation. Similarly, secreted fimbrillin in saliva could

bind to pellicle components, blocking the attachment of p.

Gingivalis.

This strategy, or a similar one, although in its infancy, could

prove to be a very useful new tool against periodontal diseases, 1

especially in populations at high risk .

Gene transfer to oromucosal keratinocytes

Epidermal keratinocytes are grown in

cultures to generate organotypic mucosal equivalents with

morphological features of the invivo tissue. By this, it has

been used in treatment of burn therapy and for treatment of

nonhealing epidermal ulcers.

There are reports that cultured oral keratinocytes

have been grafted to oral surgical defects. Which persisted at 2

these sites and exhibited normal epithelial morphology .

POTENTIAL CLINICAL APPLICATIONS OF

KERATINOCYTE GENE THERAPY

A) Genetic Diseases

Recessive monogenetic diseases:

Recessive disorders may be treated by introduction

of a normal gene into keratinocytes so that its expression

would compensate for the lack of expression of the defective,

mutated gene.

An example for the treatment of a recessive disorder

in keratinocytes is gene therapy for xeroderma pigmentosum.

This condition is caused by an inherited defect in a DNA

repair enzyme and results in an increased risk of epidermal

cancer. The goal of gene therapy would be to transfer and

express a normal copy of the repair enzyme to cause the 5disease phenotype to revert .

Dominant monogenetic diseases:

The gene addition approach used to treat recessive

disorders would not be of value in the treatment of dominant,

monogenic disorders since disease cells continue to express a 2

defective gene product .

In this case, successful gene therapy would first

require disruption of abnormal gene expression before

transferring and expressing a normal gene.

Example for a keratinocyte-specific autosomal

dominant disorder to which gene therapy is applied is 6“Epidermolysis bullosa simplex (EBS) . While EBS does not

lead to serious manifestations in oral cavity, this therapeutic

approach may be of value in learning how to treat an oral 2disease caused by dominant-acting mutation .

b) TREATMENT OF ACQUIRED DISEASES:

Treatment of infectious diseases In oral cavity HPV

and HSV infection are among the most common viral

induced lesions.

HPV has been associated with the development of

squamous cell carcinoma and benign proliferative conditions

while HSV is thought to cause primary and recurrent oral 2

ulcers .


The goal of gene therapy would be either to

protect the cells from infection or to limit the infectious

process of previously infected cells.

For ex oral cancer cells that Harbor HPV may

have their malignant phenotype altered by use of antisense 7 8molecules and ribosomes directed to the HPV

transforming genes.

- Transfer of genetically altered HSV sequences

has provided a strategy through which HSV

pathogenecity can be modified.

C)RE-EPITHELIALIZATION AND WOUND

HEALING:

Expression of gene products which stimulate

wound healing may be useful to accelerate re-

establishment of oral and epidermal integrity after injury.

Genetically modified keratinocytes transplanted

to wounds may act as biological dressing by expressing

into the wound a therapeutic protein which would favour 9wound healing .

Alternatively, a therapeutic gene could be applied

directly to the healing cells.

When gene for human epidermal growth factor

was transferred to wound, the growth factor was secreted 10

by cells in wound and healing was accelerated .

Such applications are examples of a gene therapy

approach where only transient expression of therapeutic

gene is required. This therapeutic approach may prove 2

particularly in treatment of chronic oral ulcers .

APPLYING GENE THERAPY TO ORAL CANCER:

Potential uses of gene therapy in oral cancer

include treatment of recurrent disease and adjuvant

treatment-for example, at surgically resected margins.

Localized distant metastatic disease is another potential

target of gene therapy in patients with oral cancer. Due to

the requirement for direct injection, oral cancer is a

particular appropriate target, since most primary and 11recurrent lesions are accessible to injection .

There are several general strategies utilized in a gene

therapy approach to cancer including

1) Addition of tumor suppressor gene (gene addition

therapy)

Cancer cells generally demonstrate impaired cell cycle

progression largely due to mutations and over expression

of cell cycle regulators several genetic alterations have

been described in oral cancer, including mutations of P53, 12the retinoblastoma gene (RB1), P16 & P21 .

The most extensively studied mutations in oral cancer

are those of P53. Since the protein P53 plays a role in cell-cycle

was initially tested in squamous cell carcinoma pts by

injecting the primary or regional tumor with an adenoviral

vector expressing wild type P53. Adenoviral P53 (AdP53) was

demonstrated to be safe and well tolerated, however it has 11limited tumor response .

2) Deletion of a defective tumor gene(gene excision therapy)

3) Down regulation of the expression of genes that stimulate

tumor growth (Antisense RNA).

Gene expression can usually be inhibited by RNA that

is complementary to the strand of DNA expressing the gene.

This “antisense” RNA can prevent the activity of several

known oncogenes including myc, fos and ras and can inhibit

viruses such as HSV-1, HPV and HTLV-1 such therapy can

theoretically be directed toward carcinoma cells whose

malignant phenotype is dependent upon the expression of

particular oncogenes. Inhibition of expression of these

oncogees may alter phenotype thus aborting tumor growth.

4) Enhancement of immune surveillance (Immunotherapy)

The immunologic gene therapy approach to oral

cancer involves increasing the immunogenic potential of

tumor cells or augmenting the patient's immune response to a

tumor.

5) Activation of prodrugs that have a chemotherapeutic effect

(“suicide gene therapy)

“Suicide gene therapy for cancer inserts a gene into

the tumor that encodes for a protein that will convert a non-

toxic prodrug into toxic substance.

The most extensively studied approach utilizes herpes

simplex virus Thymidine kinase (HSV-TK). This gene

encodes a viral enzyme that phosporylates ganciclovir into

monophosphate form, which is then further phosphorylated by

intracellular enzymes into an active triphosphate compound 13

that terminates DNA synthesis . Other strategies include

introduction of viruses that destroy tumor cells as part of the

replication cycle, delivery of drug resistance genes to normal

tissue for protection from chemotherapy and introduction of

genes to inhibit tumor angiogenesis.

Limitations in cancer gene therapy:

Tumor may have lost surface receptor for the vectors,

due to mutations tumor cell cycle may be too deranged to

progress to apoptosis, many cancers may not be curable by a

single modality therapy.

Future directions of cancer gene therapy are, aimed at

proper delivery system; selective and specific cancer

targeting, metastatic tumor targeting may require systemic 11

tumor specific targeting which needs different approaches .


Future perspectives:

Modification of bacteria to control the pathogenecity

of dental infections agents.

A major challenge in dentistry is the fabrication of

biomaterials for replacement or augmentation therapy

related to enamel, dentin, cementum, PDL, bone, cartilage

and oral mucosa.

For example during endodontic therapy, dentists will

be able to seed genetically developed pulpal tissue into the

canal to grow and fill the chamber.

Recombinant vaccines designed to reduce dental

caries and periodontal diseases. Promising research is in

progress related to development of vaccines against H.

simplex, human papilloma virus, human immunodeficiency

virus with significant oral complications.

Production of oral mucosal lubricants for xerostomia,

building disease resistant dental structures, delivery of gene

therapeutics for oral fungal infections and genetically based

therapeutics (eg. Endorphins, neutrotrophins) for

neurological disorder eg: Trigeminal Neuralgia

Production of systemic gene products from oral

tissues, gene therapy mouth washes to oral cancer.

Limitations of gene therapy include short lived nature

of gene therapy, immune response, problems with viral

vectors, multigene disorders, cost effective, awareness of 2

patient, it requires special knowledge and skill .

References

1)Bruce J Baum, Brian C O' Connell: The impact of gene

therapy on dentistry. JADA,Vol 126, Feb 1995,179-189.

2)Garlick J.A, Fenjves E.S:Keratinocyte gene transfer and

genetherapy. Crit Rev Oral Biol Med.7(3):1996:204-221.

3)Roemer K, Friedmann T. Concepts and strategies for human

gene therapy.Eur J Biochem 1992:208:211-225.

4)Currently approved human gene transfer studies. Hum Gene

Ther 1994:5:1067-74

5)Weatherall DJ:Scope and limitations of gene therapy. Br

Med Bull:1995:51:1-11.

6)Coulombe PA,Hutton ME, Vassar R, Fuch SE. A function of

keratins and a common thread among dfferent types of

epidermolysis bullosa Simplex diseases. J Cell Biol

1991:115:1661-1674

7)Steele C, Cowsert, Shillitoe EJ: Effects of human

papillomavirus type 18 specific antisense oligonucleotides on

the transformed phenotype of human carcinoma cell lines.

Cancer Res 1993:53:2330-2336.

8)Chen Z, Kamath P, Zhang S, Weil MM, Shillitoe EJ.

Effectiveness of three ribozymes for cleavage of an RNA

transcript from human papilloma virus type 18. Cancer Gene

therapy 2:263-271.

9)Vogt PM,Thompson S, Andree C, Liu P, Breuing K, Hatzis D

etal. Genetcally modified keatinocytes transplanted to wounds

reconstitute the epidermis. Proc Natl Acad Sci USA

1994:91:9307-9311.

10)Andree c, Swain WF, Page CP, Macklin MD, Slama J,

Hatzis D, et al. In vivo transfer and expression of a human

epidermal growth factor gene accelerates wound repair. Proc

Natl Acad Sci USA 91: 12188-12192.

11)Gleich LL. Gene theraphy for head and neck cancer.

Laryngoscope 110;2000:708-726.

12)Xi S, Grandis. JR. Gene therapy for the treatment of oral

squamous cell carcinoma. J Dent Res 82(1):2003,11-16.

Matthews T, Boehme R. Antiviral activity and mechanism of

Action of Ganciclovir. Rev Infect Dis(3):1988;490-494.

Conclusion

The early efforts show that treatment of oral diseases

will be broadly affected by impact of molecular biology.

While there is little evidence to date of the efficacy of

gene therapy in clinical trails, the potential for gene therapy is

still great, is that it may provide a new way of looking at

disease therapeutics. Gene therapy is in an early stage yet

holds great promise for its ultimate clinical application.

Dentistry will be affected profoundly by gene based

science, or current materials and methods are abandoned in

favour of emerging bioengineered technologies for disease

prevention, tissue repair and disease resistance.

“The best way to predict the future is to invent it”.


1 2Dr Thomas Varghese, DrKarthigaKannan,

3 4Dr Jassim K A, Dr Merin George,

(1&4)PG student,(2) Professor - Department of Oral Medicine &

Radiology (3)PG student - Department of Oral Pathology ,

Mar Baselios Dental College, Kothamangalam, Ernakulam (Dist).Kerala

Introduction:O d o n t o g e n i c k e r a t o c y s t s ( O K C s ) a r e

developmental odontogenic cysts of epithelial origin, first identified and described in 1876 and further characterized

1by Phillipsen in 1956. This lesion was recently renamed as keratocysticodontogenictumour (KCOT) and reclassified as an odontogenic neoplasm in the World Health Organization's 2005 edition of its histological classification of odontogenictumours. According to this edition the KCOT has been defined as ''A benign uni- or multicysticintraosseoustumour of odontogenic origin, with a characteristic lining of parakeratinized stratified squamous epithelium and potentially aggressive, infiltrative behaviour. It may be solitary or multiple. The latter is usually one of the part of inherited naevoid basal

2cell carcinoma syndrome .

Keratocystic Odontogenic TumorOf the mandibleA case report

Abstract

Key wordsOdontogenickeratocyst (OKC); Keratocysticodontogenic tumor (KCOT); Nevoid basal cell carcinoma syndrome.

Jaw cysts are very common due to the presence of o d o n t o g e n i c e p i t h e l i a l r e m n a n t s . T h e odontogenickeratocyst (OKC) is an epithelial developmental cyst of the jaws. This lesion is commonly found in the mandible, and can become quite large due to its rapid growth and its extension into the adjacent structures. In 2005 the WHO working group considered odontogenickeratocyst (OKC) to be tumor and recommended the term Keratocysticodontogenic tumor (KCOT), separating lesion from the ortho keratinizing variant. Clinically the parakeratinizing lesions are characterized by aggressive growth and tendency to recur after surgical treatment. We present the case of a 22 year old female with KCOT in relation to right posterior mandibular r eg ion . The c l i n i ca l , r ad io log i ca l , and histopathological features of this tumour and its surgical management are discussed.

Case Report: A 22 year old female patient reported to the Department of Oral medicine and radiology of Mar Baselios Dental College ,Kothamangalam,Ernakulam with a chief complaint of pus discharge from the right lower back tooth region for the past 6 months [figure 1].she noticed a displacement of teeth in the same region for the past one month [figure 2]..Rest of the dental and medical history was unremarkable.

On extra oral clinical examination there was no gross facial asymmetry noticed on the face. On intra oral examination a solitary diffuse swelling of size 2x2 cm seen in relation to the lingual aspect of 44,45,46 region.colour of the swelling is pale pink ,surface is smooth , shiny and displacement of 44,45 is noticed. On palpation the swelling is bony hard in consistency ,borders are not clearly defined ,it is not a compressible or reducible swelling with the slight expansion of lingual cortical plate [figure 3].

Fig. 1: Facial profile view of the patient demonstrating no visible swelling


Intra oral Periapical radiograph, occlusal radiograph and Orthopantomographs were performed. IOPA of 44,45,46 region shows a radiolucent area of size 3x3 cm which extends from the distal aspect of 44 to the distal aspest of 46 ,superior inferiorly from the alveolar crest and it extends downwards. [figure 4]

Lateral occlusal radiograph shows a radiolucency of size 3x1 cm seen which extends from the cervical area of 48 to distal aspect of 44 with lingual cortical plate expansion[figure 5]

OPG shows a well-defined radiolucency with sclerotic outline and scalloped borders of size 3x3 cm in relation to the 44,45,46 region. [Figure 6]

Aspiration gives blood tinged creamy fluid. Based on the history,clinical and radiographic features a provisional diagnosis of odontogenickeratocystwas made. Surgical enucliationdone under general anaesthesia and chemical cauterization with Carnoy?s solution was done.

Biopsy report shows cystic lining, surrounded by moderately dense connective tissue. The parakeratinised corrugated epithelium is almost 6-8 layers thick. The retiridegs are absent and sloughing of the epithelium from the connective tissue is also noted. The basal cells are columnar w i t h p o l a r i z e d n u c l e i ; c y s t i c l u m e n s h o w s fibrillareosinophilicmaterial suggestive of keratin.

Based on histopathology we finally diagnosed as Keratocysticodontogenic tumor [figure 7].No recurrence has been determined after 9 months of post operative follow up [figure 8].

Fig. 2: Intraoral shows displacement of teeth.

Fig. 3 :. Intraoral shows swelling on the lingual aspect

Fig. 4: IOPAR shows radiolucency with scalloped outline

Lateral occlusal view shows lingual cortical plate expansion.

Fig. 6 : OPG shows well defined radiolucency

Fig. 7 Histopathology 10x zoom

with sclerotic outline and scalloped border.

Fig. 5


Discussion: KCOT is a benign uni or multicystic, i n t r aosseous tumour o f odon togen ic o r ig in , Keratocysticodontogenic tumors (KCOT) occur from the first to the ninth decades with a peak in the second and third decades. Males are more commonly affected than females. The mandible is involved more frequently than the maxilla, the percentage of KCOTs occurring in the mandible ranges from 65- 83% of cases.With roughly one-

2half originating at the angle of the mandible . While the KCOT is generally regarded as anintraosseous lesion, rare peripheral cases have beenreported. The majority of cases involve the gingival oralveolar mucosa in the canine-

3premolar region .M o s t k e r a t o c y s t i c o d o n t o g e n i c t u m o r s a r e discoveredincidentally during review of routine dental radiographs. Occasionally, pain, swelling, and drainage will herald asecondary infection of the cyst. Imaging studies generallyshow unilocularradiolucencies with well-demarcatedsclerotic margins. Larger lesions may become multi-loculated with scalloped borders. The cyst is often associated with an impacted tooth, and mimic radiologically like dentigerous cyst. Adjacent teeth may be displaced, but root resorption rarely occurs. CT scans and contrast-enhancedMRI may be useful in assessment of

[1, 2,,3 ].cortical perforationand soft tissue involvement Histologically OKCs have been classified into three categories: parakeratinised, Orthokeratinised, or a combination of the two types. Mostly (86.2%) were parakeratinised, 12.2% were orthokeratinised, and 1.6% had features of both orthokeratin and parakeratn. Orthokeratinised OKCs have a substantially lower recurrence rate than parakeratinised. This case is a parakeratinisedvarity. Multiple OKCs are found in some patients. Gorlin and Goltz established the association of multiple basal cell epitheliomas, jaw cysts and bifid ribs, a combination that is referred as the “Gorlin -Goltz Syndrome”, or the nevoid basal cell carcinoma syndrome

4(NBCCS) .

Conclusion:KCOT patients are mostly asymptomatic. Most Keratocysticodontogenic tumors are discovered incidentally during review of routine dental radiographs. It is more aggressive and recurrent one. In any case clinical and radiographic follow-up is mandatory for years after surgery, because recurrence of this lesion may occur even years later.

References:1.Shear M (1992). Odontogenickeratocyst In: Cysts of the Oral Regions, 3rd ed.2.Keratocysticodontogenic tumor a case report and review of literature Asokan et al:Int J Dent Case Reports 2012; 2(1): 87-91.3.Pindborg JJ and Hansen J: ActaPatholMicrobiolScand Studies on odontogenic cyst epitheliu m 1963;58:283- 2944.Thompson L, Goldblum J, editors. Head and neck pathology; avolume in the series foundations in diagnostic pathology. Phila-delphia: Elsevier; 2006.5.KeratocysticOdontogenicTumor,Elizabeth A et al. Head

.and Neck Pathol (2010) 4:9496.

M u l t i p l e t r e a t m e n t s f o r t h e Keratocysticodontogenictumor have been proposed and debated. The challenge lies in minimizing both the risk of recurrence and morbidity of an extensive resection. Numerous modalities ranging from decompression alone, to simple enucleation with or without curettage, to resection have been employed in the management of KCOT. [9] Simpleenucleation has a recurrence rate of 17% to 56%.

Fig. 8: post operative OPG after9 months.


1 2Dr Santhini G Nair, Dr S Rajesh

1.Senior lecturer, Department Of Conservative Dentistry

&Endodontics.NIMS.

2.Prof.,& HOD. -SMIDS,Kulasekharam

Introduction

Current knowledge regarding caries disease has substantially evolved within the last decade. Understanding of its dynamic lead to a risk factor approach which left the treatment of cavities a minor role to play in the whole planning. Using this background, Minimally Invasive Dentistry (also minimum intervention dentistry - MID) builds its framework.The “minimally invasive” approach totreating dental caries incorporates the dental science of detecting, diagnosing,intercepting and treating dental caries on the microscopic level. This approach to treating dental caries includes many non- surgical modalities, as well as the key concept that dental caries should be treated as an infectious disease and includes the following concepts:Early caries diagnosis.The classification of caries depth and progressionusing radiographs.The assessment of individual caries risk (high, moderate, low).

Minimal Invasive DentistryA new perspective

Abstract

Key words

The current treatment philosophy is to prevent and detect diseases at the earliest stage in order to avoid invasive treatment. With the current understanding of the nature of dental diseases and its process, the treatment philosophy is now changing to a more conservative approach and the concept of minimal intervention is gaining popularity in modern dentistry throughout the world. The aim of this review article is to give dental professionals an overview of the concepts of MID and recent innovations in the treatmentof dental caries.

Minimal Invasive Dentistry, Dentin caries, Caries Excavation

The reduction of cariogenic bacteria, to decrease the risk of further demineralization and cavitation.

The arresting of active lesions. The remineralization and monitoring of non-

cavitated arrested lesions. The placement of restorations in teeth with

cavitatedlesions, using minimal cavity designs. The repair rather than the replacement of

defective restorations. Assessing disease management outcomes atpre-

established intervals.

MINIMAL CAVITY DESIGNS Preservation of natural tooth structure should be the guiding factor for the smallest, as well as the largest, cavity. Cavity preparation design and restorative material selection depend on occlusal load and wear factors. The tunnel preparation is performed byaccessing the carious dentin from the occlusalsurface, while preserving the marginal ridge. Tunnel preparations are technicallydifficult to do because of access and visibility and the small amount of tooth structure removed. Internal preparations preserve the marginal ridge and the proximal surface enamel. Minibox or slot preparations involve theremoval of the marginal ridge, but do not includethe occlusal pits and fissures if caries removal inthese areas is not necessary. These cavities mayhave either a box or a saucer shape and may berestored with resin-based composite oramalgam.

M I N I M A L I N VA S I V E P R E P A R A T I O N TECHNIQUES(Noack et al. (2004)

1.Excavation techniques:i)Manual rotary.ii)Sono abrasion.iii)Air abrasion.iv)Chemo-mechanical excavation.v)Enzymatic digestion.vi)Photobalation.

2. Disinfection techniques:a)Ozone treatmentb)Photodynamic therapyc)Antibacterial therapy3. Sealing techniquesa)Fluoride releasing materialsb)Dentin adhesivesC)Antibacterial resin materials


ART uses the beneficial property of GIC such as:Fluoride release.Inhibition of secondary caries.Ability to remineralziation.Conventional Excavation with BursCarbon-steel or tungsten-carbide burs Tungsten-carbide burs replaced carbon-steel burs once the process of hardening steel with tungsten carbide was introduced to the dental bur industry. Microscopic tungsten-carbide particles are held together in a matrix ofcobalt or nickel at the head (working end) of the bur. The head has typical spiral like cutting edges with or without additional cross cuts to improve cutting efficiency. Carbon steel burs possess the same caries-removing propertiesas tungsten-carbide burs and are less expensive, but they are much more prone to corrosion and dulling. For caries removal, a round bur is recommended with diameters corresponding to the size of the carious lesion.Water irrigation is optional because generally low-speed (700 to 800 rpm) counter-angle

hand-pieces are employed. It is generally advised to start carious dentin excavation from the periphery towards the centre of the lesion in order to minimize the risk of infection in case of accidental pulp exposure. Larger burs are recommended for this reason as well. Tungsten-carbide or carbon-steel burs in low-speed counter-angle

hand-pieces are the most efficient method to excavate carious lesions in terms of time and are therefore still the most widely used caries-excavation method. Polymeric burs

In an attempt to develop a selective caries-removal

rotating instrument, a “plastic” bur was made of a

polyamide/ imide (PAI) polymer, possessing slightly

lower mechanical properties than sound dentin.

However, soon it became clear that if the bur touches

sound or caries-affected dentin, it quickly becomes dull

and produces undesirable vibration, making further

cutting impossible.

ATRAUMATIC RESTORATIVE TECHNIQUE: This technique was developed in Tanzania in mid 1980s and introduced into clinical setting in 1990s. It mainly evolved in response to the unavailability of restorative care in population groups with limited resources. It involves the removal of only soft, demineralized tooth tissue with hand instruments followed by filling the cleaned cavity with adhesive

The blade design was developed to remove dentin by locally depressing the carious tissue and pushing it forward along the surface until it ruptures and is carried out of the cavity. The commercial version of these burs (SmartPrep, SSWhite Burs; Lakewood, NJ, USA) consisted of a polymer(PEKK polyether-ketone-ketone) with a particular hardnessof 50 KHN, which was higher than the hardness attributed to carious dentin (0 to 30 KHN), but lower than that of sound dentin (70 to 90 KHN). As opposed to conventional carbide burs, their cutting edges were not spiralled but straight. One disadvantage was that by keeping to the recommendation to excavate caries from the centre to the periphery in order to avoid contact with sound tooth tissue, the

bur would be prematurely and irreversibly damaged.

Ceramic burs A new line of slow-speed rotary cutting instruments made of ceramic materials is now commercially available for removal of carious dentin. The CeraBurs (Komet-Brasseler; Lemgo, Germany) are all-ceramic round burs made of alumina-yttria stabilized zirconia and are available in different diameter sizes The manufacturer claims that besides its high cutting efficiency in infected, soft dentin, the use of this instrument for caries removal replaces both the explorer and the excavation spoon (commonly needed to evaluate the degree of decay removal) by simultaneously providing tactile

sensation, self-evidently reducing preparation.

AIR ABRASION Air abrasion is an old technology that is finding a new place in modern science based dentistry.The concept of air abrasion was originally given by Dr. R.B. Black, way back in 1943, in the era of 'extension for prevention', operative

stdentistry. The 1 commercial air abrasion equipment was AIR DENT by SS White Company. Air abrasive technology uses a high speed stream of purified alumina particles traveling in high velocity stream of air to remove the tooth structure. Hence this technique has recently termed by Kelvin as Kinetic cavity preparation Modern version of AirDENT (1992)Abrasive The abrasive used is purified aluminium oxide particles or alpha-alumina i.e. a non-toxic substance often in medicine, food. The particle size is about 27.5µ .Currently 2X alumina particle sizes are available with 3 pressure choices.Science and anatomy It removes only the decayed tooth structure leaving the healthy tooth structure intact, hence the pain and discomfort associated with the traditional use of the needle and drill is avoided and no impingement on vital tissues.

Air abrasive tools, techniques and procedures A setting of 60 psi with 27µ particle size and 0.014 inch tip is comfortable and adequate for starting most procedures.a) Clean the surface of the tooth, place caries detector die.b) Place the nozzle at right angle 45° and no more than 1mm to the surface of the tooth to be treated.c) Start with 3 second burst at 80 psi to trace out the grooves, pits and fissures of the occlusal surface of the molar.

Technique:Isolate tooth with cotton rolls Clean tooth surface with wet cotton pellet Widen lesion entrance with HatchetCaries removal with ExcavatorPulpal protection Ca(OH) paste 2

Cavity conditioning and rinsing Condense with press finger technique Check the bite and remove excess material


the burst should be interrupted over areas of sound enamel such as isthmus separating the mesial and distal pits of mandibular molars and oblique ridge of maxillary molars.d) Observe and diagnosis for residual decay which if present should be removed (at once setting 60 psi) in a similar manner and use short controlled bursts.e) One aspect of micro-dentistry is the amount of powder that ends up in the mouth.High speed suction is always used. Also a 2 x 2 inch wet gauge may be placed in the mouth.

Main indication:Class I, III and V carious lesions:Class I: Excellent when tooth does not show radiographic evidence of significant caries and teeth may have potentially fissured occlusal grooves.Class III: Small Class III most common and important indications. Non carious tooth must be protected with rubber dam, 0.002 inch (50µm) thick matrix band.Margin repair composite laminate.Pediatric patients.Health compromise in which LA cannot be given.Apprehensive patients.Less common:Class II, IV difficult and unpredictable needs to be mastered.

Contraindications:Severe dust allergy.AsthmaChronic pulmonary disease.Recent extraction.Recent periodontal surgery or PDL disease.Subgingival preparation.Wound / lacerations in mouth e.g. after recent orthodontic appliances.Advantages:Patient acceptance: lack of vibration, decreased heat, decreased pressure and pain produced during cavity preparation.Unique ability to produce extremely conservative preparations.Smell of carious material is eliminated.

Disadvantages:Technique not familiar, so dentists require a learning period to occlusion themselves limited visibility.Tactile perception minimal.Only small cavity preparations can be accomplished.Al O gets accumulated. Excellent suction required.2 3

Caries excavation by “sono-abrasion” is based on the use of cutting tips coupled to high-frequency, sonic, air-scaler

hand-pieces under water cooling. Oscillate in the sonic region <0.5KHz. Tips describe on elliptical motion with a transverse distance between 0.08-0.015mm and longitudinal movement 0.055-0.135mm. Diamond coated on one side with 40µm grit diamond. Air cooled with H O with flow rate, 20-2

30mL/min.Operational air pressure is 3.5bars. Have 3 three different instrument tips

OLength ways halved torpedo (9.5mm long, 1.3mm wide).oSmall hemisphere (1.5mm diameter).oLarge hemisphere (12.2mm).

Torque applied should be 2N.This technique was unilaterally developed using different shaped tips to help prepare predetermined cavity outlines.

CHEMO MECHANICAL CARIES REMOVAL Non-invasive alternative for the removal of carious dentine. It mainly involves the chemical softening of carious dentin followed by its removal of gentle excavation. A CMCR reagent is based on this principal causing further degradation of the partially degraded collagen, by cleavage of the polypeptide chains in the triple helix and / or hydrolyzing the cross linkages.MOA of chemo-mechanical caries:

Dentine consists of mineral (70%), water 10%) and

an organic matrix (20%) , of this organic matrix, 18% is

collagen .Collagen is an unusual protein which contains large rdamount of proline and 1/3 of amino acid content is

glycine.The polypeptide chains are coiled into triple helices

which are known as tropocollagen units. These tropocollagen

units then orientate side by side to form a fibreil bonds between

the polypeptide chain and between the tropocollagen units

form cross-links and give the collagen units stability. In dentin

the fibres are in the form of a dense meshwork which gets

mineralized.When caries occur, acids produced by plaque

bacteria by anaerobic fermentation of carbohydrate initially

cause solubilisation of the mineral in enamel. As the process

progresses, dentinal tubules provide access for penetrating

acids and subsequent invasion by bacteria which results in a

decrease in pH and cause further acid attack and

demineralization. When the organic matrix has been

demineralized, the collagen and other matrix component are

susceptible to attack and forming the zones of caries.In this,

out of the 2 zones of carious dentine, theCMCR reagent causes

the further degradation of partially degraded collagen in the

outer layer by cleavage of polypeptide chains in the triple helix

and / or hydrolyzing the cross linkages.High cost.Walls rounded and uneven.

Difficult to remove existing restoration.Soft caries absorbs alters the particles.

EXCAVATION BY SONO-ABRASION


Development of chemo-mechanical agents

The principal of CMCR is based on arising

from studies by Goldman and Kronman working in New

Jersey US in the 1970's. They stated with studying the

effect of NaOCl, which is a non-specific proteolytic

agent, on the removal of carious material from dentine. It

alone, however was too erosive. Hence, they

incorporated it into Sorensen's buffer (which contains

glycerine, sodium chloride, sodium hydroxide) a

reaction occurred which resulted in a product effective in

removal of glycine to form N-monochloroglycine and

the reagent subsequently became known as GK-1019. In

subsequent studies they found that the system was more

effective if glycine was replaced by amino butyric acid,

the product then being N-monochloroaminobutyric acid

(NMAB) also designated GK-101E.The mechanism of

action of NMG and NMAB on collagen is still unclear

and knowledge of the chemistry of chlorination of amino

acids and their effects is still very limited. Originally it

was thought that the procedure involved chlorination of

the partially degraded collagen in the carious lesion and

the conversion of hydroxyproline to pyrrole-2-

carboxylic acid.11 More recent work suggests that

cleavage by oxidation of glycine residues could also be

involved.This causes disruption of the collagen fibrils

which become more friable and can then be removed.

The NMAB system was patented in the US in

1975 and a further patent taken out by the National Patent

Dental Corporation, New York in 1987. It received FDA

approval for use in the USA in 1984 and was marketed in

the 1980's as Caridex. It consisted of two solutions,

Solution I containing sodium hypochlorite and Solution

II containing glycine, aminobutyric acid, sodium

chloride and sodium hydroxide. The two solutions were

mixed immediately before use (pH approx.11) which

was stable for one hour.A delivery system was also

available whichconsisted of a reservoir for the solution, a

heater and a pump which passed the liquid warmed to

body temperature through a tube to a hand piece and an

applicator tip which came in various shapes and sizes.

The solution was applied to the carious lesion by means

of this applicator which was used to loosen the carious

dentine by a gentle scraping Application was continued

until the dentineremaining was deemed sound by normal

clinical tactile criteria. With suitable accessible soft

lesions, after 510 minutes treatment only clinically

sound dentine remained.

CARISOLV Because of the time required for CMCR treatment and large volumes of solution needed and the fact that the delivery system was no longer commercially available, use of CMCR, despite its potential, became minimal.

During this time however, Medi team in Sweden continued to work on the system and the latest CMCR reagent known as Carisolv hit the headlines in January 1998. Although it is similar to the caridex and NMAB systems, it is in the form of a pink gel which can be applied to the carious lesions with specially designed hand instruments. It is marketed in 2 syringes, to be mixed prior to application.

Syringe 1: 0.5% NaOCl.Syringe 2: 3 amino acids: glutamic acid, leucine lysine.NaCl.Erythosine (to make it readily visible).Carboxymethyl cellulose (for viscosity).H O. 2

NaOH pH 11.Mode of action Carisolv is alkaline in nature with a pH of around 11.Upon mixing, the positively and negatively charged groups of amino acids become chlorinated due to presence of NaOCl and NaOCl constituents. This leads to interaction with dentin which involves proteolytic degradation of collagen rather than demineralization of collagen, softening and removal of the carious altered dentin and preserving the sound dentin. The gel consistency allows the active molecules access to the dentin for a longer period than the equivalent irrigating solution in Caridex system. This gel also helps by lubricating the hand instrument specifically designed for Carisolv.

PEPSIN-BASED CARIES EXCAVATION A new experimental gel consisting of pepsin in a phosphoric acid/sodium biphosphate buffer is being considered as an alternative chemo-mechanical caries excavation agent (SFC-VIII, 3M ESPE;Seefeld, Germany). The main advantage of this new enzyme-based solution is that it can be more specific by digesting only denatured collagen(after the triple-helix integrity is lost) than the sodium hypochlorite-based agents. According to the manufacturer, the phosphoric acid dissolves the inorganic component of carious dentin, while it at the same time gives pepsin access to the organic part of the carious biomassto selectively dissolve the denatured collagen. To avoid overexcavation, the SFC-VIII gel should be used in combination with a prototype plastic instrument having hardness between that of sound and infected dentin

OZONE THERAPY FOR CARIES EXCAVATION Ozone therapy is based on the promise that the primary carious lesion when exposed to ozone becomes sterile and remineralizes after some time. Principle Ozone therapy is based on the concept of complete elimination of a acidophilic bacteria, fungi and viruses and thus creating a sterile environment of remineralization to take place. It has been proven that 10 seconds of application of ozone gas at a concentration of 2200ppm could eliminate 99% of the carious micro-flora.

Effect of Ozone: (On caries, plaque, saliva an dental alloys)o Ozone quickly dissipates in water and kills the microorganisms via a mechanism involving the rupture of their membrane in such lesions.


oStrong oxidizer for cell walls and cytoplasmic membrane of bacteria.

oLeads to oxidative decarboxylation of plaque pyruvate generating acetate and CO2 as by product.

oIt oxides volatite sulphur.FLUORESCENCE-AIDED CARIES EXCAVATION (“FACE”) This technique was developed as a direct method to clinically differentiate between infected and affected carious dentin. Based on the fact that several oral microorganisms produce orange-red fluorophores as by-products of theirmetabolism (porphyrins), infected carious tissue will fluoresceespecially in the red fraction of the visible spectrumdue to the presence of proto- and meso-porphyrins. Inthis way, continuous visual detection of orange-red fluorescenceduring caries excavation was thought to be

convenientfor clinicians.By feeding a slow-speed hand-piece with a fiber-optic violetlight source (370 to 420 nm) and allowing the operatorto use a 530-nm yellow glass filter, areas exhibiting orangeredfluorescence can be selectively identified and removedwith the bur.

LASER EXCAVATION The word “laser” is an acronym for “Light Amplification by Stimulated Emission of Radiation” The indications for the use of lasers in dentistryare nowadays broad, varying from caries diagnosis, disinfection of periodontal pockets or root canals, photodynamic therapy of oral tumours, soft-tissue surgery, caries removal, and cavity preparation. Especially in the field of operative dentistry, erbium lasers have been pointed out as most promising due to their specificity in ablating enamel and dentin without side effects to the pulp and surrounding tissues when the approprate parameters are employed. The erbium-loaded yttrium-aluminum-garnet (Er:YAG) and the erbium,chromium: yttrium-scandium-gallium-garnet(Er,Cr:YSGG) lasers are the two types of erbium-based devices currently available on the market.The mechanism by which enamel and dentin are removed during Er:YAG irradiation consists of explosive subsurface expansion of water interstitially trapped in the dental hard tissues. During irradiation, the water molecules absorb the incident radiation, causing sudden heating and water evaporation. As a result, a high-stream pressure is formed, inducing a violent, yet controlled expansion and ejection of dental hard tissue components.50 In contrast, the Er,Cr:YSGG laser system, usually known as a “laser powered hydrokinetic system”, delivers photons straight into an air-water spray directed to the target tissue. This phenomenon induces micro-explosive forces into water droplets, which is said to contribute significantly to the mechanism ofhard-tissue removal.

PHOTO-ACTIVATED DISINFECTION ( PAD) Low power laser energy in itself is not particularly lethal to bacteria but is useful for a photochemical activation of oxygen releasing dyes. Singlet oxygen released from the dies causes membrane and DNA damage to microorganisms.

It can be undertaken with a range of visible red and near infra red laser systems using low power (100mw) visible red semiconductor diode lasers and tolonium chloride and (toluidine blue) dye are now available.PAD technique has been shown to be effective for killing bacteria in complete biofilms, such as sub-gingival plaques, which are typically resistant to the action of antimicrobial agents.It can be used effectively in carious lesions, since visible red light transmits well access dentine, and can be made species specific by tagging the dye with monoclonal antibodies.

Major clinical applications:Disinfection of root canals.Periodontal pockets.Deep carious lesions.Sites of peri-implantitis.

Advantages:Does not give rise to deleterious thermal effects.Does not cause sensitization and killing of adjacent human cells fibroblasts, keratinocytes.Residual reactive O2 species produced by E are removed by enzyme covalance naturally present in tissue and lactoperoxidase and normal component of saliva.

CONCLUSION With the development of new dental restorativematerials and advances in adhesive dentistry, abetter understanding of the caries process and thetooth's potential for remineralization and changesin caries prevalence and progression, the management of dental caries has evolved from G.V. Black's“extension for prevention” to “minimally invasive.” Minimally invasive dentistry is based on alarge body of scientific evidence that has beensummarized and discussed. The future promisesfurther evolution toward a more primary preventive approach, facilitated by emerging technologies for diagnosis, prevention and treatment.Altogether, irrespective of the caries excavation methodchosen, it remains clinically recommended to finish the cavity margins in clean/sound tooth tissue in order to achieve the best performance of adhesives, while being at the sametime least invasive with regard to caries excavation and most conservative with regard to sound-tissue preservation.


REFERENCES1.Ahmed AA, Garcia-Godoy F, Kunzelmann KH. Self-limiting caries therapy with proteolytic agents. Am J Dent 2008;21:303-312.2.Alfano RR, Yao SS. Human teeth with and without dental caries studied by visible luminescent spectroscopy. J Dent Res 1981;60:120-1223.Allen KL, Salgado TL, Janal MN, Thompson V. Removing carious dentinusing a polymer instrument without anesthesia versus a carbide bur withanesthesia. J Am Dent Assoc 2005;136:643-651.4.Aoki A, Ishikawa I, Yamada T, Otsuki M, Watanabe H, Tagami J, Ando Y, Ya-mamoto H. Comparison between Er:YAG laser and conventional techniquefor root caries treatment in vitro. J Dent Res 1998;77:1404-1414.5.Armengol V, Jean A, Rohanizadeh R, Hamel H. Scanning electron microscopic analysis of diseased and healthy dental hard tissues after Er:YAGlaser irradiation: In vitro study. J Endod 1999;25:543-546.6.Arnold WH, Konopka S, Gaengler P. Qualitative and quantitative assessment of intratubular dentin formation in human natural carious lesions.CalcifTissInt 2001;69:268-273.7.Bachmann L, Diebolder R, Hibst R, Zezell DM. Changes in chemical composition and collagen structure of dentine tissue after erbium laser irradiation. SpectrochimActa A 2005;61:2634-2639.8. Banerjee A, Kidd EA, Watson TF. In vitro evaluation of five alternativemethods of carious dentine excavation. Caries Res 2000;34:144-150.9. Banerjee A, Kidd EA, Watson TF. Scanning electron microscopic observations of human dentine after mechanical caries excavation. J Dent2000;28:179-186.10.Banerjee A, Watson TF, Kidd EA. Dentine caries excavation: A review ofcurrent clinical techniques. Br Dent J 2000;188:476-482.11.Barwart O, Moschen I, Graber A, Pfaller K. Invitro study to compare the efficacy of N-monochloro-D, L-2-aminobutyrate (NMAB, GK-101E) and waterin caries removal. J Oral Rehab 1991;18:523-529.12.Bayne SC, Thompson JY, Studervant CM, Taylor DF. Instruments andequipment for tooth preparation. In: Roberson TM, Heymann HO, Swift-JrEJ (eds). Studervant's Art & Science of Operative Dentistry. St. Louis:Mosby, 2002:307-344.13.Beeley JA, Yip HK, Stevenson AG. Chemo-mechanical caries removal: A review of the techniques and latest developments. Br Dent J2000;188:427-430.14.Bjorndal L, Thylstrup A. A structural analysis of approximal enamel carieslesions and subjacent dentin reactions. Eur J Oral Sci 1995;103:25-31.15.Black GV. Cavity preparation. In: Black GV (ed). A work on operative dentistry. Chicago: Medico-Dental Publishing Company, 1908:105-116.16. Black RE. Technique for non-mechanical preparation of cavities and prophylaxis. J Am Dent Assoc 1945;32:955-965.


1 2DrAparna Mohan , DrAnuroopa A. , 3Dr James Rex

1 2& 3Senior Lecturer, Reader, Department of Prosthodontics, SMIDS,

Kulasekharam.

INTRODUCTION

Dentistry has moved into a new era in which it can no

longer be practiced as a secluded specialty. In order to

satisfy the needs of the patients a team approach is

preferred where in multiple specialties pool in over an

individualapproach. Likewise, thevarious periodontal

aspects to be considered in designing a prosthesis is dealt

as “Periodontal Restorative Inter-relationship”.

in periodontally compromised dentition

A systematic approach

Abstract

Key words

The goal of every dentist is to restore the carious or

missing dentition with fixed partial denture which is

biologically acceptable to the gingival tissues.The

dental surgeon will always face difficultieswhile

managing a periodontally compromised dentition

due to its weak nature and complexity.In this article

we discuss the various treatmentmodalities for a

periodontallycompromised dentition and the

modification needed to be done while treating a

weak abutment teeth.

Interdisc ipl inary approach, Per io-prostho

relationship,Knife edge finish line.

Rehabilitation of periodontally compromised

dentition requires a multidisciplinary approach where in a

periodontist,an endodontist and a maxillofacial

prosthodontist goes hand in hand for a successful treatment.

Prosthetic rehabilitation of periodontally compromised

dentition facilitates improvement in esthetics as well as

function while splinting of these teeth also enhances the

support through distribution of masticatory forces. The

various treatment procedures done for a periodontally

compromised dentition can be dealt under two headings, (A)

the pre-prosthodonticperiodontalprocedures which includes

periodontal procedures done prior to definitive

p r o s t h o d o n t i c t r e a t m e n t a n d ( B ) t h e

prosthodonticmodifications done while restoringa

periodontally compromised dentition.

A) ROLE OF PERIODONTAL PROCEDURES IN PROSTHODONTICS

1Mucogingival Surgery Muco-gingival surgery is one of the

most common surgical procedure done for the coverage of

denuded roots, to increase attached gingival and to create

adequate vestibular depth. The various techniques to

increase attached gingivaare the free gingival autografts

and apical displacement flap surgeries which not only

improves the esthetics but also the function of the abutment

teeth (Figure-1 and 2).

1Root Coverage Surgery As the name implies, this

technique isrecommended for the coverageof root of the

abutment teeth. There are mainly two techniques for this

and they are Langer's technique,wherein a connective tissue

graft is used under a partial thickness flap and Tarnow

technique which utilizes a semi-lunar coronally displaced

flap.

Prosthodontic considerations


A ) P R O S T H O D O N T I C M O D I F I C AT I O N O F T H E

RESTORATION IN PERIODONTALLY COMPROMISED

DENTITION

A periodontally compromised dentition should be

restored with extreme care and precision. In such cases a metal

margin finishing is preferredover ceramic or acrylic veneering

as the polished surface of the metal reduces theaccumulation of

plaque and pathogenic micro-organism.It is indicatedin cases

with severe cervical erosion, in extensive restorations or caries

extending beyond gingival crest, in short clinical crowns andin

persistent root sensitivity. In such cases a subgingival margin

should be prepared with extreme care. When the intra-

crevicular margins are adjacent to thin gingiva on the root,

special care should be given so that the sulcular contours of the

artificial crown should be flat, mimicking the shape of the root.

The gingiva adjacent to a flat root surface develops a thick free

gingival margin when the underlying bone is thick. In these

situations it may be advisable to create a thicker intra-crevicular 5

crown contour similar to that of a natural crown5,6

Crown Contour - In an abutment teeth with furcation

involvement and Grade I or early Grade II mobility a full

coverage restoration is indicated. Theprinciples of tooth

preparation are same as that for a normal tooth except that the

preparation has to be fluted or barreled into anatomic

depressions following the exact contour of the root. On the

crown, the plaque retention is on the buccal and lingual surfaces

occuring primarily at the infra-bulge area of the tooth. Hence

reduction or elimination of infra-bulge is indicated to reduce

plaque retention.There are various theories of crown contour

put forward to discus this aspect and they areThe Gingival

Protection Theory, The Gingival stimulation theory, The

Muscle action theory andThe Theory of access for oral hygiene.

Embrasure - Another most commonclinical scenarioin

periodontally compromised teeth is an open embrasure which

results in horizontal food impact leading to halitosis.It also acts

as anidus for growth of microorganism.In such cases the teeth

may be reshaped with a restorations or crown to relocate

gingival embrasures close to the new level. The proximal

surfaces are recontoured and broadened so that the contact areas

are apically repositioned.

1Crown Lengthening Procedures Intooth witha short

clinical crown, it is necessary to increase the size of the

clinical crownto enhance the retention of a cast

restoration. This is done with an apically displaced

flap and ostectomy. 2

Ridge Augmentation Procedures - Ridge

augmentation procedures are done to correct excessive

loss of alveolar bone that most commonly occurs in the

anterior region as a consequence of advanced

periodontal disease.This is managed either by the

placement of a thick mucosal autograft obtained from

palate or tuberosity or by placement of non-porous

dense hydroxyl-apatite under a split thickness flap or a

pouch created under a full thickness flap and/or a

double flap technique used in conjunction with

hydroxyl-apatite.


But if the proximal contact area is excessively broad andmade

bulky in restoration,it will result incrowding out the gingival

papillae in the cervical region. This can make oral hygiene

difficult resulting in gingival inflammation and attachment

loss.

Contact Area-Contact area of the teeth also changes in patients

with periodontally compromised dentition.Itshould be directed

incisal or occlusal and buccal in relation to the central fossa,

except in connector between maxillary first and second molars

Pontic Design - Like a crown contour,pontics not only follows

all design principle but also some additional points associated

with the contour of the tissue facing surfaces. In the mandibular

posterior region where esthetics is not a major consideration, a

spheroidalpontic is the design of choice.. A spheroidalpontic

contacts the ridge without pressure the tip of the ridge or the

buccal surface. In the maxillary posterior area, the modified

ridge lap satisfies both esthetics and hygiene. Mandibular

anterior area also requires a ridge lap design. When there is

excessive bone loss and a rigid connector in a non-esthetic

posterior region, the pontic is not required to touch the ridge.

There should be at least 3mm of space so that the patient can

maintain hygiene. In non esthetic posterior areas, when there is

excessive bone loss, pontic is not required to touch the ridge.7Occlusion -A freedom in centric occlusion with even contact

in anterior as well as posterior region with anterior guided

occlusion is the preferred occlusion in a periodontally

compromised dentition. The occlusal forces should be guided

in axial direction and the steepness of the cuspal inclines

should be reduced with minimum over jet and overbite in the

anterior teeth. During lateral excursion there should not be any

contacts in cantilevers.8Provisional Restoration - The interim restoration should

behave a fit, polish and contour as for the final restoration.

Long term temporary restoration if indicated should be

definitely fabricated in heat cure acrylic material.9SplitningAs Part Of Periodontal Therapy -Splinting refers to

joining together of two or more teeth for stabilization. It is done

to protect teeth with mobility, to distribute occlusal forces of

teeth weakened by loss of periodontal support and to prevent

natural tooth from migration.Splinting is indicated in Lindhe's

class IV and V.

It is contraindicated in patients with gingivitis and early

or moderate periodontitis and Lindhe's situation III.

Splints are broadly classified in to temporary or

reversible splints or provisional and permanent splints.

Reversible splints includethe ligature wire splint,

circumferential wiring splint, bonded splints and

removable appliances splint. Removable appliance

splints are the Hawley's Retainer, a continuous clasp

RPD and swing-lock RPD.Permanent splints fabricated

after completion of the periodontal therapy can be a 10

telescopic prosthesis , fixed partial denture with non

rigid connector, fixed partial denture with rigid

connectors, Maryland splints and long span fixed partial 11

denture with cross arch stabilization .(figure-3)

12MANAGEMENT OF HEMISECTIONED TOOTH

Hemisection is defined as a surgical separation of a

multi-rooted tooth through the furcation area in such a

way that a root or roots may be surgically removed along

with the associated portion of the crown. In mandibular

molars, there are three option and they are as follows :

(1)Mesial root with crown removed while retaining the

distal root and crown,(2) mesial root with crown retained

wherein distal root and crown is removed and (3) both

crown and root are separated but retained.


In a hemi-sectioned mandibular tooth an intra-

crevicular margin should be given to cover portions of the root

resected. The margin should be apical to pulp chamber floor

andnot closer that 3mm without interfering the biologic

width. A knife edge finish line or chamfer is the finish line of

choice. If hemisection is done to molar and both the sections

are retained, then individual crown with both units soldered

together is the ideal treatment option. If only one root is

retained after hemisection, then it can be restored with a single

crown or can be also be used as an abutment for short span

three or four unit FPD. If hemisection is done in maxillary

molar,then it is called skyfurcation. There are three from of

hemi-section in maxillary first molar and they are as follows-

Distobuccalhemisection, mesiobuccalhemisection and

palatal hemisection. Mesiobuccal root is most commonly

removed while the palatal root is retained. If the palatal

section is retained and FPD used as abutment, then the

emergence profile should be made flat with slight lingual flare

(figure-3).

PERIODONTAL PROCEDURES IN REMOVABLE 13

PROSTHESIS

In patients with partially edentulous situation with

periodontally compromised dentition, the various treatment

options are the periodontal prosthesis, swing lock cast partial

denture and the conventional cast partial denture. The

components of the partial denture should be placed without

affecting the periodontal health of the abutment teeth.

damaged endodontically treated teeth- a clinical

report.LecistaRomana De Stomatologievol VI 2010, 156-

159.Among direct retainers, anI-bar type of clasp has little or

no detrimental effect of periodontal health. This design

utilizes a gingivally approach clasp, mesially positioned

occlusal rest and a proximal plate. Any direct retainer should

be passive and exert no force on teeth when the partial denture

is at rest. An occlusal rest should be designed so that the

occlusal forces are directed along the vertical axis of the tooth.

The angle formed by the occlusal rest and the vertical minor

connector should be less than 90°. By doing this, the occlusal

forces are directed along the long axis of the abutment teeth.

Major connectors in a cast partial denture should not

impinge the free gingival margins. It shouldbe placed

6mm away from the gingival margin. When periodontally

compromised mandibular anterior teeth require

stabilization, a special design of major connector can be

used for splinting teeth together where a lingual plate

should extend to the middle third of the surface of the

mandibular anterior teeth or a double lingual bar is

preferred treatment of choice.

CONCLUSION

Teeth preserved by periodontal therapy should be

restored with cast restoration for its normal function.

Success of a periodontally weakened teeth lies on

rehabilitating it with an occlusal scheme which improves

its stability and designing a prosthesis which favors the

esthetics and function. Hence an interdisciplinary

approach is essential in treating a periodontally

compromised dentition wherein a periodontist saves the

teeth and a prosthodontist restores its function.

REFERENCES

2.Rosensteil3.W. F. P. Malone, D.L.Koth. Tylman's theory and practice of fixed

prosthodontics. Eighth edition.Ishiyaku Euro America, Inc. Publishers. Tokyo. St. Louis.

4.Herbert. T.Shillingburg. Fundamentals of fixed prosthodontics, Third edition. Quintessence publishing, IL.

5.Behrand D, Cerammometal restoration with supra-gingival margins. JPD; 1982:47, 625

6.Becker M.C. et al, Current theories of crown contours margin placement and pontic design. JProsthetDent;1981: 45: 268-271.

7.Dawson. 8.Yuodelis, R A. Faucher R; Provisional restorations; an integrated

approach to periodontics and restorative dentistry, Dent Clin North Am.1980: 24(2) 285-303.

9.Kegel W, SelipskyH and Phillips C . The effect of splinting on tooth mobility during initial therapy, J of clinical Periodontal.1979: 6;45-58.

10.Gordon T telescope reconstruction;An approach to oral rehabilitation. J A D A 1966, 72,97-105.

11.Kourkouta. S,Hemmings. K.W, Laurd .L, restoration of periodontallly compromised dentition using cross arch bridges. Principles of perio-prosthetic patient management. BDJ 2007.4. 189-195

12.Appleton IE ; Restoration of root resected teeth. J Prosthet dent 1980; 44; 150-153.

13.Periodontal consideration in removable treatment , a review of literature. Haralambor Petridis, Timothy J Hempton, Int J Prosthodont 2001; 14:164- 172.

14.UmutCakan, BulemYuzugullu.prosthodontic and periodontal reconstruction .

1.Newman, Takei, Klokkevold, Carranza. Carranza's clinical periodontology. Tenth edition. Reed Elsevier India private limited, Noida.


1 Dr Ramandeep Singh Bhullar, 2 3DrS.Ram Kumar, Dr Nanda Kumar,

4Prof C Ravindarn

1)Reader, Department of Oral and Maxillofacial surgery, Sri Guru Ram Das Institute of Dental sciences and Research, Sri Amritsar.

2) & 3)Professor, 4) Professor and Head Department of Oral and Maxillofacial surgery, Sri

Ramachandra Dental College,Chennai- 600116

Public Recognition

A STUDY

Abstract

Although there is no supporting evidence there is a perception that public is unfamiliar with what an oral and maxillofacial surgery is and what an oral and maxillofacial surgeon does? The purpose of this study was to evaluate through a survey the level of awareness among general public and health care professionals of the proper providers of treatment for the maxillofacial region and their level of knowledge of the specialty of oral and maxillofacial surgery The results showed that little above 70%of medicos and almost all of the dentists were aware of the specialty, but the response from public was only 52%. The name of the speciality was well understood by the health care professionals but not by 48% of the general public .The study showed that one half of the public is still unaware with what an oral and maxillofacial surgery is and what an oral and maxillofacial surgeon does.

Introduction:

Despite all the progress that has occurred in the speciality of oral and maxillofacial surgery majority of the population is still unaware of the speciality and what its practitioners do. This was

2,3supported by studies in British literature in 1996 and 1994 . The survey showed that medical and dental practitioners have heard of the speciality but they were not fully aware of what was the scope of oral and maxillofacial surgeon. More than half of the general public was not aware of the speciality named oral and maxillofacial surgery.Ever since the change in the name of the specialityfrom “oral surgery” to “oral and maxillofacial surgery” in 1977, there has been concern whether public understands the meaning of the name Although it accurately describes the anatomic region and scope of treatment provided by its practitioners, the term maxillofacial not only is difficult to pronounce but it may not be the one with which they are not familiar. According to a survey published in 2002, speciality designation identification rate for OMFS was 77% in Virginia Common Wealth University

1Richmond . Therefore this study was designed to provide an answer to question regarding recognition and scope of oral and maxillofacial surgery among Indian population

Materials and Methods:

A questionnaire was designed for the

purpose of this study. Questionnaire was divided

into two parts, part 1had three questions asking

the opinion of the responder a) whether they

have heard the name of this speciality, b) they

understand the name and c) the basic

qualification of oral and maxillofacial surgeon,

Part 2 had 15 specific condition in which

responders were asked to choose whether

maxillofacial surgeon has role in treatment of

these conditions or not .the study included five

different groups general public, medical

practitioners, medical students, dental

practitioners and dental students. Total of 600

survey sheets were sent and maximum of 100

responses per group were considered.

Key words

Oral&Maxillofacial surgery ,Public awareness,Survey

of Our Speciality


Whether OMFS has role intreatment of these conditions?General Medical Medical Dental Dental

Public Students Practitoners Students PractitonersOral cancer 42 73 68 83 92Dental problems 34 79 79 92 98Cuts on face 25 49 66 59 76Neck surgery 17 00 26 90 64Orbital injuries 17 19 33 23 56Cleft lip and palate 37 30 63 71 72Brain injuries 00 00 07 00 00Wisdom teeth removal 59 54 75 81 100Sports injuries 37 75 84 85 74Sinusitis 09 00 10 21 42Acne, moles and warts 09 19 10 23 10Malpositioned jaws 50 52 72 81 64Cosmetic surgery 25 52 70 85 48Dental implants 42 52 72 85 82

Table I: values show percentage and responders opinion whether maxillofacial surgeon has a role in treatment of these specific conditions, the values shows the positive response which indicates that maxillofacial surgeon has a role in treatment of these conditions

Discussion:

This survey demonstrated that almost all of

dental practitioners, majority of medical practitioners

and half of public were aware of speciality named oral

and maxillofacial surgery. Medical professionals were

not aware of the wide scope of oral and maxillofacial

surgeon. Public has little knowledge about scope of oral

and maxillofacial surgery. This might be attributed to

long and complicated name of speciality. There is a

tremendous overlap between the speciality of ENT,

plastic surgery and OMFS, with no definitive procedure

to each speciality. Each surgeon is credentialed for a

surgical procedure on his or her level of training and

expertise

in general the survey demonstrated that public does not

recognize the role of maxillofacial surgeon in cosmetic

surgery, cleft lip and palate surgery and neck surgeries.

General public would prefer the services of maxillofacial

surgeon in treating the fracture of jaws, removal of

wisdom tooth

This survey was conducted in the department of

oral and maxillofacial surgery Ramachandra medical

college and research institute Chennai. Therefore the

results may not be applicable in other parts of the country.

References:

1.Daniel M Laskin, John A Ellis, Al M Best; Public recognotin of speciality designations. Of oral MaxillofacSurg 60:1182-1185, 2002.2.Hunter J M, Rubiaz T, Rose L; Recognition of the scope of oral and maxillofacial surgery by the public and health professionals. J Oral maxillofacSurg 54: 1227, 1996.3.Ameerally P, Fordyce AM, Marin IC; So you think they know what we do, The public and professional perception of oral and Maxillofacial Surgery. Br J Oral Maxillofacial Surg 32: 142,1994.

Conclusion:Despite all the progress that has occurred still a large portion of our population is still unaware of the speciality. If the patients are to receive the best treatment available it is essential to educate health care consumers and providers about the different specialities available and their role within health profession.

However it appears that greater progress must be

made in education of medical students and more importantly

general public, if the speciality of oral and maxillofacial

surgery is to be practiced in its full scope.


1. A. Sri Kennath J Arul (MDS., MBA.,) Professor (Oral and Maxillofacial Pathology),

Best Dental Science College, Madurai, Tamil Nadu, India2. A. Sri Sennath J Arul (MBBS., MD.,)

Medical Practitioner, Tamilnadu, India. 3. Sonika Verma (MDS)

Senior Lecturer, Oral Pathologist, India.4. Rashmika Verma, (BDS)

Dental Surgeon, Rotorua, New Zealand

and it’s role in

A review

Introduction A paradox in metabolism is that while the vast majority of complex life requires oxygen for its existence, oxygen is a highly reactive molecule that damages living organisms by producing reactive oxygen species. Reactive oxygen species (ROS) is a collective term used by biologists to include not only the oxygen centered radicals (nascent oxygen, superoxide and hydroxyl) but also some non-radical derivatives of oxygen such as hydrogen peroxide, hypochlorus acid and ozone. The cells of the body are constantly exposed to endogenous as well as exogenous oxidants. The exposure to oxidants is by patho-physiological conditions like inflammation, ischemia or reperfusion injuries and external factors like tobacco, radiation or alcohol etc.

Abstract

Key words

Reactive oxygen species have emerged as the major final common pathway of tissue injury and that failure to counter their deleterious effects increases the likelihood of developing degenerative diseases. It is clear that cells require an effective defense against such oxidative stress and an important line of defense is provided by antioxidants. Further, the role of oxidative damage in carcinogenesis is increasingly being speculated. Cancer causation is linked experimentally and clinically to cellular and DNA damage by oxidants, and therefore antioxidants may properly be viewed as potentially reducing the risk of cancer. With the aforementioned in mind, the aim here is to briefly discuss antioxidants, with emphasis on its role in oral cancer.

Reactive oxygen species, antioxidants, oxidative stress, oral cancer

This increases the intracellular level of ROS or oxidative stress; that can produce major interrelated derangements of cell metabolism, including DNA strand breakage (often an early event), raises intercellular calcium, damages membrane ion transporters and/or other specific proteins, and cause peroxidation of lipids. Indeed in most human diseases, oxidative stress is a secondary phenomenon, a

1consequence of the disease activity. This oxidative damage/stress, associated with ROS is believed to be involved not only in the toxicity of xenobiotics but also play patho-physiological role in ageing of skin and several diseases like atherosclerosis, cataract, cognitive dysfunction, cancer (neoplastic diseases), diabetic retinopathy, critical illness such as sepsis and acute respiratory distress syndrome, shock, chronic inflammatory diseases of the gastrointestinal tract, organ dysfunction, disseminated intra-vascular coagulation, deep injuries, respiratory burst inactivation of the phagocytic cells of immune system, production of nitric oxide by the vascular endothelium, ischemia/reperfusion injury and release of iron

2and copper ions from metalloproteins. To protect the cells and organ systems of the body against ROS, a highly sophisticated and complex antioxidant protection system has been evolved that includes a variety of components both endogenous and exogenous in origin; that function interactively and synergistically to neutralize free radicals. These include: nutrient-derived antioxidants, antioxidant enzymes and metal binding proteins. The various defenses are complementary to one another because they act on different oxidants or in different

3cellular compartments. The aim of the present article is to briefly discuss antioxidants, with emphasis on role of antioxidants in oral cancer.

Antioxidants Oral Cancer

Antioxidants are the substances or agents that scavenge reactive oxygen metabolites, block their generation or enhance endogenous antioxidant capabilities. They are

4named so because of their ability to combat oxidation.According to the mode of action, antioxidants can be

4,5grouped into:

a)Scavenging antioxidants: They prevent oxidative stress by literally scavenging radicals as they form. Vitamins like C, E, carotenoids and curcumin are scavenger molecules.

b)Preventive antioxidants: They function largely by sequestering transition metal ions and preventing Fenton reactions, they are therefore largely proteins by nature e.g: transferrin, lactoferrin, ceruloplasmin, and desferrioxamine.c)Enzyme antioxidants: They function by catalyzing the oxidation of other molecules e.g. superoxide dismutase, glutathione peroxidase and catalase.

3,6According to the type, antioxidants can be grouped into:a)Enzymatic: Superoxide dismutase (SOD), Catalase, Glutathione peroxidases, Glutathione transferase and Peroxidase.

b)Non-Enzymatic: Nutrient (-Tocopherol, -Carotene, Ascorbate, Glutathione, Selenium)Non-nutrient (Ceruloplasmin, Transferrin, Uric acid, Peptides)


Role of Antioxidants in Oral Cancer:

Oral cancer is one of the 10 most frequent cancers worldwide, with about three quarters of all cancers occurring in

thdeveloping countries. It represents the 5 most common cancer in the world. There is a striking difference in the incidence and the mortality rates across the world, with highest rates generally registered in a few developing countries including India, Pakistan and Bangladesh, where this is the most common form of cancer. On the basis of cancer registry data, it is estimated that annually about 1,20,000 new oral cancer cases develop in India. The role of oxidative damage in carcinogenesis is increasingly being speculated. Cancer causation is linked experimentally and clinically to cellular and DNA damage by oxidants, and therefore antioxidants may properly be viewed as potentially

7reducing the risk of cancer. Ames suggested that antioxidants are capable of

producing cancer regression, inhibition of metastasis and 8 9

prevention of carcinogenesis. According to Shklar,antioxidants have the ability to destroy cancer cells through three major mechanisms.

a) Immuno-enhancement: In normal human beings, the development of cancer cells stimulates a potent immune response that locates the cancer cells and destroys them. Signals produced by the developing cancer cells are interpreted by the host's immune system. The immune cells are capable of elaborating cytotoxic chemicals that can infiltrate and destroy the cancer cells. The cytotoxic chemicals include: tumor necrosis factor- (TNF-), carried by macrophages and mast cells; tumor necrosis factor- (TNF-) carried by lymphocytes.b) Molecular Genetic pathway: Antioxidant nutrients can: a) Enhance the expression of wild type p53, which is a well-known cancer suppression gene product b) Diminish the expression of mutant p53, which is the oncogene expressed in a large number of malignant tumors.

c) Angiogenesis inhibition: Proliferating cancer cells produce cytokines or chemical mediators and stimulate the proliferation of endothelial cells to form an extensive vascular supply to nourish the developing tumor. If the blood supply to the tumor does not develop, the tumor growth would be sufficiently inhibited. Antioxidants stimulate cellular differentiation and prevent development of such blood supply.

Role of carotenoids:

Carotenoids are a family of antioxidant phytonutrients including alpha carotene, beta carotene, lutein and lycopene. The antioxidant actions of carotenoids are based on their

singlet oxygen quenching properties and their ability to trap

peroxyl radicals, scavenge free radicals and protect the cell membrane lipids from the harmful effects of oxidative degradation. The quenching involves a physical reaction in which the energy of the excited oxygen is transferred to the carotenoid, forming an excited state molecule.

The ability of â-carotene and other carotenoids to quench excited oxygen, however, is limited, because the carotenoid itself can be oxidized during the process. This is known as auto-oxidation. This is dose-dependent and dependent upon oxygen concentrations. At higher concentrations, it may function as a pro-oxidant and can activate proteases. â-Carotene is also scavenger of

peroxyl radicals, especially at low oxygen tension. Carotenoids act as antioxidants by reacting more rapidly

10with peroxyl radicals than do unsaturedacyl chains.

Vitamin A: The role of vitamin A in epithelial differentiation was first demonstrated in 1925 when squamous metaplasia was reported in vitamin A deficient rats. The first study that associated vitamin A deficiency

11,12with cancer appeared in 1941. In laboratory studies, the carotenoids have been

shown to have anti-mutagenic activity in bacterial systems. In many cell culture systems, carotenoids prevent transformation induced by chemicals and

radiation.The mechanism involved in cancer inhibition by these agents has not yet been determined; but they produce effects on cell differentiation; immunologic function; interaction of cells with growth factors, such as epidermal growth factor; and changes in gene expression. Such mechanism may be important in their anticarcinogenic

13activity. Suda et al showed that the topical administration of â-carotenoids reduced the number and size of carcinomas in hamsters that had been exposed to topical

147,12-dimethylbenz (a) anthracene (DMBA). Others also have shown a decreased incidence and severity of DMBA-induced tumors with the use of beta carotenoid

15supplements.

Lycopene: Lycopene is a carotenoid without provitamin-A activity and one of the most potent antioxidants and has been suggested to prevent carcinogenesis by protecting critical biomolecules including lipids, low-density lipoproteins (LDL), proteins and DNA. Lycopene, because of its high number of conjugated double bonds, exhibits higher singlet oxygen quenching ability

16compared to â-carotene or á-tocopherol.

Lycopene is highly lipophilic and is most commonly

located within cell membranes. It is therefore expected

that in the lipophilic environment, lycopene will have 17

maximum ROS scavenging effects. Lycopene was

shown to be the most effective antioxidant in protecting

the 2,29-azobis 2,4-dimethylvaleronitrile (AMVN)-

induced lipid peroxidation of the liposomal membrane. It

was also found to protect lymphocytes against NO -2

induced membrane damage and cell death twice as 18efficiently as â-carotene.

Levy et al showed that lycopene inhibited the growth of

human endometrial, mammary and lung cancer cells

grown in cultures and was more effective than â-19carotene.


References:

1.Young IS and Woodside JV. Antioxidants in health and disease. J Clin Pathol 2001; 54:176- 86. 2.Halliwell B, Gutteridge JMC. In: Free radicals in Biology and Medicine.

nd2 ed.1989: p89-98. 3.Langseth L. Oxidants, antioxidants, and disease prevention. ILSI Europe concise monograph series 1995:4. 4.Rangan U, Bulkley GB. Prospects for treatment of free radical-mediated tissue injury. Br. Med. Bulletin 1993;49:700-18. 5.Ames BN, Shigenaga MK, Hagen TM. Oxidants, antioxidants, and the degenerative diseases of aging. Proceedings of the National Academy of Sciences 1993;90:7915-22. 6.Agarwal S, Sohal RS. Relationship between aging and susceptibility to protein oxidative damage. Bioche Biophys Res Commun 1993;194:1203-6. 7.Percival M. Antioxidants. Clinical nutrition insights. NUT031 1/96 Rev. 10/98.p 1-4. 8.Ames BN. Dietary carcinogens and anticarcinogens. Oxygen radicals and degenerative diseases. Science 1983;221:1256-64. 9.Shklar G, Schwartz J. Tumor Necrosis factor in experimental cancer regression with alphatocopherol, beta-carotene, canthaxanthin and algae extract. Eur J Cancer Clin Oncol 1998;24:839-50. 10.Miller NJ, Sampson J, Candeias LP, Bramley PM, Rice-Evans CA. Antioxidant activities of carotenes and xanthophylls. FEBS Lett. 1996;384:240-2. 11.Lippman SM, Kessler JF, Meyskens FL Jr. Retinoids as preventive and therapeutic anticancer agents (Part I). Cancer Treat Rep 1987;71(4):391-405. 12.Halter SA. Vitamin A: Its role in the chemoprevention and chemotherapy of cancer. Hum Pathol 1989;20:205-9. 13.Bertram JS, Peng A, Rundhaug JE. Carotenoids have intrinsic cancer preventive action. FASEB J 1988;2:1413A 14.Suda D, Schwartz J, Shklar G. Inhibition of experimental oral carcinogenesis by topical beta-carotene. Carcinogenesis 1986;7:711-5. 15.Das U. A radical approach to cancer. Medical Science Monitor 2002;8(4): RA 79-92. 16.Agarwal S, Rao AV. Tomato lycopene and low density lipoprotein oxidation: a human dietary intervention study. Lipids 1998;33:981-4. 17.Rao AV. Bioavailability and in-vivo antioxidant properties of lycopene from tomato products and their possible role in the prevention of cancer. Nutr Cancer 1998;31:199-203. 18.Agarwal S, Rao AV. Tomato lycopene and its role in human health and chronic diseases. CMAJ 2000;163(6):739-44. 19.Levy J, Bosin E, Feldmen B, Giat Y, Miinster A, Danilenko M et al. Lycopene is a more potent inhibitor of human cancer cell proliferation than either á-carotene or ß-carotene. Nutr Cancer 1995;24: 257-66. 20.LaVecchia C. Mediterranean epidemiological evidence on tomatoes and the prevention of digestive tract cancers. Proc Soc Exp Biol Med 1997;218:125-8. 21.Dorgan JF, Sowell A, Swanson CA, Potischman N, Miller R, Schussler N et al. Relationship of serum carotenoids, retinol, á-tocopherol, and selenium with breast cancer risk: results from a prospective study in Columbia, Missouri (United States). Cancer Causes Control 1998;9:89-97. 22.Kucuk O, Sakr FH, Djuric Z, Li YW, Velazquez F, Banerjee M, et al. Lycopene supplementation in men with prostate cancer (PCa) reduces grade and of preneoplasia (PIN) and tumor, decreases serum prostate specific antigen and modulates biomarkers of growth and differentiation [abstract P1.13]. International Conference on Diet and Prevention of Cancer; 1999 May 28-June 2; Tampere, Finland.

rd23.Friedrich W. Vitamins. New York. Walter de Gruyter Publishing 1988; 3 Ed. 992 - 1012. 24.Carr AC, Frei B. Toward a new recommended dietary allowance for vitamin C based on antioxidant and health effects in humans. Am J Clin Nut 1999;69:1086-107. 25.Ames BN, Shigenaga MK, Hagen TM. Oxidants, antioxidants, and the degenerative diseases of aging. Proceedings of the National Academy of Sciences 1993;90:7915-22. 26. Brigelius-Flohe R, Traber MG. Vitamin E: Function and Metabolism. FASEB J 1999:13:1145-55. 27.Brigelis-Flohe R, Kelly F, Salonen J, Neuzil J, Zingg J, Azzi A. The European Perspective On Vitamin E : Current Knowledge And Future Research. Am J Clin Nut. 2002;76:703-16. 28.Shklar G, Schwartz J, Grau D, Trickler DP, Reid S. Prevention of exper imenta l cancer and immunost imula t ion by v i tamin E(immunosurveillence). J Oral Pathol Med 1990;19:60-4. 29.Gridley G, McLaughlin JK, Block G, Blot WJ, Gluch M, Fraumeni JF Jr. Vitamin supplement use and reduced risk of oral and pharyngeal cancer. Am J Epidemiol 1992; 135:1083-92.

LaVecchia C, suggested that the Mediterranean diet,

which is rich in fruits and vegetables, including tomatoes,

could be responsible for the lower cancer incidences in that 20 region. Dorgan JF et al,in a recent case-control study from

the Breast Cancer Serum Bank in Columbia, Missouri,

concluded that only serum lycopene and none of the other

antioxidants showed a significant inverse relationship with 21 breast cancer risk. Agarwal S and Rao AV, in their studies

involving healthy human subjects in their laboratory

indicated that lycopene from traditional tomato products was

absorbed readily, increased serum levels and lowered

oxidative damage to lipids, lipoproteins, proteins and 16

DNA. Kucuk O et al, suggested that tomato extract

supplementation in the form of capsules lowered the PSA 22

levels in prostate cancer patients.

Role of Vitamin C: Vitamin C, a potent, water-soluble

antioxidant, has been known as an essential micronutrient

since the late 1700s, when the British Navy supplemented

the diet of their sailors with citrus fruits to prevent 23

scurvy. As an antioxidant, it scavenges free radicals and

reactive oxygen molecules, which are produced during 24metabolic pathways of detoxification.

Vitamin C's antioxidant mechanisms help to prevent cancer in several ways. It combats peroxidation of lipids that are linked with ageing process and degeneration. In elderly people, it was found that administration of 400 mg of vitamin C/day for a period of one year was associated with reduced serum lipid peroxide levels. Vitamin C can work to protect DNA from damage caused by free radicals. It arrests harmful effects by stimulating detoxifying enzymes in the liver. It blocks the formation of fatal antigens, decreasing the risk of cancers of oral cavity, larynx, esophagus, lung, pancreas, stomach, colon and rectum, breast, ovary, endometrium and prostrate. It has been shown that a low intake of L-Ascorbic Acid (L-AA) is associated with an increased risk of cancers of the stomach, esophagus, oral cavity, larynx, and cervix. The association between L-AA and oral carcinoma is based solely on dietary assessments that have concluded that an increased risk was present when fruit and vegetable intake

25was low.Role of Vitamin E (á-Tocopherol): Vitamin E occurs in nature in eight different forms, which differ greatly in their degree of biological activity and is the major lipid soluble antioxidant found in cells. Vitamin E is more appropriately described as an antioxidant than a vitamin. This is because, unlike most vitamins, it does not act as a co-factor for enzymatic reactions. It is a chain breaking antioxidant i.e. it is able to repair oxidising radicals directly, preventing the

26,27chain propagation step during lipid peroxidation.

Documents

Jomida Vol-1 Issue-3 May 2013