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www.dentalnews.com Volume XVII, Number I, 2010

THE EFFECTS OFENLARGED ADENOIDS

ON A DEVELOPINGMALOCCLUSION

Hydrogen peroxide bleaching

Egyptian DentalAssociation

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The effects of enlarged adenoids on adeveloping malocclusionDr. Kevin WILLIAMS, Dr. Derek MAHONY

Complete Denture Stability DuringChewingMax BOSSHART CDT

Hydrogen peroxide bleaching: Effect ofvarious concentrations on mercury and othermetal ions release from admixed and spheri-cal dental amalgamDr. Neveen M. AYAD

Calcium Hydroxide and Glass Ionomerliners: The Prevalence of Use amongProsthodontists, Pediatric and GeneralDentists in Different Countries.Dr. Jaber A. TAKI

Greater New York Dental Meeting

Egyptian Dental Association

Product Review

EDITORIAL TEAM

COORDINATORART DEPARTMENT

SUBSCRIPTIONADVERTISING

PHOTOGRAPHYTRANSLATION

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DENTAL NEWS – Sami Solh Ave., G. Younis Bldg.POB: 116-5515 Beirut, Lebanon.Tel: 961-3-30 30 48Fax: 961-1-38 46 57Email: [email protected]: www.dentalnews.com

DENTAL NEWS IS A QUARTERLY MAGAZINE DISTRIBUTED MAINLY IN

THE MIDDLE EAST & NORTH AFRICA IN COLLABORATION WITH

THE COUNCIL OF DENTAL SOCIETIES FOR THE GCC.

Statements and opinions expressed in the articles and communications herein are those of the author(s) and

not necessarily those of the Editor(s) or publisher. No part of this magazine may be reproduced in any form, either electronic or

mechanical, without the express written permission of the publisher.

INTERNATIONAL REVIEW BOARD

Pr. M.A. Bassiouny BDS, DMD, MSc, Ph.D. Director International Program, Temple University, Philadelphia, USA.Pr. N.F. Bissada D.D.S., M.S.D Professor and Chairman, Department of Periodontics, Case Western ReserveUniversity, USA.Pr. Jean-Louis Brouillet D.C.D, D.S.O. Chairman, Department of Restorative Dentistry, Aix-Marseille II, France.Pierre Colon D.C.D., D.S.O. Maître de conférence des universités, Paris, France.Dr. Jean-Claude Franquin, Directeur de l’Unité de Recherche ER116, Marseille, France.Pr. Gilles Koubi D.C.D., D.S.O. Department of Restorative Dentistry, Aix-Marseille II, France.Pr. Guido Goracci. University LA SAPIENZA, School of Medicine & Dentistry, Roma, Italia.Dr. Olivier Hue, Faculté de chirurgie dentaire de Paris VII, rue Garancière, Paris, France.Brian J. Millar BDS, FDSRCS, Ph.D. Guy’s, King’s, and St. Thomas’ College School of Medecine & Dentistry,London, UK.Pr. Dr. Klaus Ott, Director of the Clinics of Westfälischen Wilhelms-University, Münster, Germany.Wilhelm-Joseph Pertot DEA, Maître de conférence, Aix-Marseille II, France.Pr. James L. Gutmann, Professor and Director, Graduate Endodontics, Baylor College of Dentistry, Dallas, Texas,USA.Pr. Dr. Alfred Renk, Bayerische Julius-Maximilians-University, Würzburg, Germany.Dr. Philippe Roche-Poggi DEA. Maître de conférence des universités, Aix-Marseille II, France.Michel Sixou D.C.D., D.E.A. Department of Priodontology, Toulouse, France.Pr. M. Sharawy B.D.S., Ph.D. Professor and Director, Department of Oral biology, Medical College of Georgia,Augusta, Georgia, USA.

Alfred Naaman, Nada Naaman, Jihad Fakhoury,Dona Raad, Antoine Saadé, Lina Chamseddine,Tarek Kotob, Mohammed Rifai, Bilal Koleilat, Mohammad H. Al-JammazLina JadaaKrystel KouyoumdjisMicheline Assaf, Nariman NehmehJosiane YounesAlbert SaykaliGisèle Wakim, Marielle KhouryTony Dib1026-261X

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ABSTRACTThis article reviews upper airway obstruction caused by hypertro-phied adenoids and the possibilities of a subsequent malocclusion.Early diagnosis and treatment of pathological conditions thatcan lead to the obstruction of the upper airways is essential toanticipate and prevent alterations in dental arches, facial bonesand muscle function. Correct nasal breathing facilitates normalgrowth and development of the craniofacial complex (Figure 1).Important motor functions such as chewing and swallowingdepend largely on normal craniofacial development. Any restrictionto the upper airway passages can cause nasal obstruction possiblyresulting in various dentofacial and skeletal alterations.1 Upperrespiratory obstruction often leads to mouth breathing (Figure2). Habitual mouth breathing may result in muscular and posturalanomalies which may in turn cause dentoskeletal malocclu-sions2. Hypertrophy of the adenoids, and palatine tonsils, are oneof the most frequent causes of upper respiratory obstruction(Figure 3). Philosophies regarding the treatment of adenoidhypertrophy range from dietary control and environmental mod-ifications to dentofacial orthopaedics, change of breathing exercises,and surgical procedures.

INTRODUCTIONThe aims of this article are (1) to highlight the skills and toolsthat assist the clinician in identifying upper airway obstruction;

(2) to improve the diagnosis of adenoid hypertrophy; and (3) toimprove the classification and treatment of associated malocclusions.The methodology used in this literature analysis consists of athorough review of narrowly tailored research and Journal articles.The paradigm explored in each article involves upper airwayobstruction, adenoid hypertrophy and malocclusion. The resultsand conclusions stemming from these articles generally fall intothree categories:

(1) That hypertrophied adenoids have a definitive effect resulting inskeletal malocclusion;3

(2) That hypertrophied adenoids, coupled with other factors,may aid in the development of skeletal anomalies4; and

(3) That adenoid hypertrophy hasno effect on airway obstructionand malocclusion.

The research in this area isexpansive, but largely inconsistent.Thus, the cause and effect rela-tionship of adenoid hypertrophyand malocclusion must be care-fully examined on a case by casebasis5. Regardless of the variousresearcher’s conclusions, one

THE EFFECTS OF ENLARGED ADENOIDSON A DEVELOPING MALOCCLUSION

Dr. Kevin Williams DDS1, Dr. Derek Mahony, DDS, MSc in Orthodontics.2

1. [email protected]. [email protected]

Fig.1 Fig.3

Fig.2

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theory remains common – that airway obstruction caused byadenoid hypertrophy and malocclusion are related. The degreeof that relationship and what it affects is still under debate. Thispaper attempts only to highlight the positive existence of thisrelationship and its possible effects regarding dentofacial growthand development.

BASIC FACIAL GROWTH AND DEVELOPMENTDevelopments in the understanding of human craniofacialgrowth have stemmed from histological and embryologic studies,radiographic cephalometry, correlation of growth and facialanomalies analysis of surgical interventions, animal research andother science fields.6 Despite these studies, we are still waitingfor a definite consensus regarding the controlling mechanism ofcraniofacial tissue.Postnatal facial growth is influenced by genetic and environmentalfactors.2 Most facial growth and development occurs during thetwo childhood growth peaks. The first growth peak occurs duringthe change from primary to permanent dentition (between 5and 10 years of age) and the second growth peak occursbetween 10 and 15 years of age.2 The study of the early years oflife shows that by the age of four (4), 60 percent of the cranio-facial skeleton has reached its adult size. By the age of twelve,90 percent of facial growth has already occurred.7 By age seven(7) the majority of the growth and development of the maxilla iscomplete and by age nine (9) the majority of the growth anddevelopment of the mandible is complete. Proper facial growthis affected either positively or negatively, early in life, by thesequential occurrences of four major factors: 1. The cranial base must develop properly; 2. The naso-maxillary complex must grow down and forwardfrom the cranial base;3. The maxilla must develop in a linear and lateral fashion; 4. A patent airway must develop properly. The relationship between the naso-maxillary complex and thecranial base is significant for aesthetic reasons and proper facialbone, muscle and soft tissue support. To allow proper downwardand forward rotation of the mandible, the maxilla must beadequately developed, in width, for acceptance of themandible. Any limitation on mandibular rotation may affect the

relationship of the condyle to the glenoid fossae (in the temporalbone) resulting in multiple TMJ problems. An improper airwaywill affect the global individual growth.8 The simultaneousgrowth of these factors is not nearly as significant as how thesefactors interrelate during facial growth and development. Forexample, the basic design of the face is established by a series ofinterrelated factorial developments. The naso-maxillary complexis associated with the anterior cranial fossae. The posteriorboundary of the maxilla determines the posterior limits of themidface. This structural plane is significant to facial and craniumdevelopment. The basic structural format of facial growth anddevelopment is dependent on, and governed by, the interrelationof multiple functional matrices. These functional matricesinclude a phenomenon of bone displacement and growth at theTMJ with the maxillary forward and downward movement equalingmandibular growth upward and downward. The displacement andgrowth phenomenon is responsible for the spatial relationshipnecessary for functional joint movement resulting in the finalresult of facial growth.9 Additionally, muscle adaptions affectdentoskeletal development. The integration of the muscu-loskeletal system affects respiration, mastication, deglutition,and speech.2

This basic understanding of facial growth and development isrelevant as adenoidal tissue enlargement coincides with majorfacial growth, i.e. they occur simultaneously. Facial growth maybe restricted by abnormal development of adenoidal tissueresulting in abnormal swallowing and breathing patterns (Figure 4).

ADENOIDAL GROWTH AND DEVELOPMENTLymphoid tissue is normally present as part of the Waldeyer’stonsillar ring in the form of a nasopharyngeal tonsil (Linder-Aronson 1970). The Waldeyer’s ring is the system of lymphoidtissue that surrounds the pharynx. This system of tissue includesadenoids and pharyngeal tonsils; lateral pharyngeal tonsils; lateralpharyngeal bands; palatine tonsils and lingual tonsils (Figure 5).Tonsils and adenoids have disparate embryonic origins and cytologyeven though they are both part of Waldeyer’s ring.10 Bacteria mayplay a role in adenoid hyperplasia. Specifically, different pathogens,such as Haemophilus influenza and Staphylococcus aureus, have beenassociated with lymphoid tissue hyperplasia. The adenoid lymphoid

structures arelined with ciliatedrespiratory-typeepithelium whichis normally distrib-uted throughoutthe upper andp o s t e r i o rn a s o p h a r y n xwalls. During thepresence of disease,the distribution of

Fig.4

Fig.5

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ORTHODONTICS

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the dendritic cells (antigen presenting cells) is altered. The resultis that there is an increase in dendritic cells in the crypts, andextrafollicular areas, and a decrease in surface epithelium den-dritic cells.Lymphoid tissue is normally not apparent in the early infantstage of life. Marked symptoms of adenoid development aremost common in the childhood age range of 2 – 12. Duringadolescence a decrease in adenoid size is noted as current withthe growth of the nasopharynx. Rarely is adenoid tissue presentin adults and when it is noted it is usually in an atrophic condition.The cause of the involution of the Waldeyer’s ring is still underinvestigation.12 The imbalance in the relationship between theenlargement of the nasopharynx/nasopharyngeal airway and theconcomitant growth of adenoid tissue can result in reducedpatent nasopharyngeal airway and increased nasopharyngealobstruction.10

The growth of adenoidal tissue as demonstrated by a bell curve,peaks at or near age six (6) and also begins involution at or nearthis age as well (Figure 6). Facial growth is coupled with adenoidalgrowth. As the cranial base forms the roof of the nasopharynx,a close examination of the growth and development of the cran-iofacial complex becomes significant for evaluation of the sizeand configuration of the nasopharyngeal airway. Any abnormaldevelopment regarding this craniofacial complex may affect thenasopharyngeal airway. Abnormal adenoidal growth that occursduring childhood, may consume the nasopharnx and extendthrough the posterior choanae in the nose.13 This excessive ade-noidal growth usually interferes with normal facial growth andcan result in abnormal breathing patterns, congestion, snoring,mouth breathing, sleep apnea;4 Eustachian tube dysfunction/otitismedia, rhinosinusitis, facial growth abnormalities, swallowingproblems, reduced ability to smell and taste, and speech prob-lems.12 Theoretically, many clinicians believe the blockage shouldbe removed as soon as possible through a surgical procedurecalled adenoidectomy. However, according to a study conduct-ed by Havas and Lowinger one-third of child study patients, withtraditional adenoidectomies, were ineffective with intranasalextensions of the adenoids obstructing the posterior choanae.For this segment of the study population the “powered-shaveradenoidectomy” was effective in the complete removal of the

obstructive adenoid tissue ensuring postural patency.13

UPPER AIRWAY OBSTRUCTION AND MOUTH BREATHINGDuring normal nasal respiration, the nose filters, warms andhumidifies the air in preparation for its entry into the body’slungs and bronchi. This nasal airway also provides a degree ofnasal resistance in order to assist the movements of thediaphragm and intercostals muscles by creating a negativeintrathoracic pressure. This intrathoracic pressure promotes airflowinto the alveoli.7,15

Correct normal resistance is 2 to 3.5 cm H2O/L/Sec and results inhigh tracheobronchial airflow which enhances the oxygenationof the most peripheral pulmonary alveoli. In contrast, mouthbreathing causes a lower velocity of incoming air and eliminatesnasal resistance. Low pulmonary compliance results7. Accordingto blood gas studies, mouth breathers have 20% higher partialpressure of carbon dioxide and 20% lower partial pressures ofoxygen in the blood, linked to their lower pulmonary complianceand reduced velocity.7,16

Contributing factors in the obstruction of upper airways include:anatomical airway constriction, developmental anomalies,macroglossia, enlarged tonsils and adenoids, nasal polyps andallergic rhinitis.5 However, for purposes of this paper the focusshall be on enlarged adenoids as the major contributing factor.There are numerous studies that link adenoid hypertrophy withnasopharyngeal airway obstruction to the development of skeletaland dental abnormalities.14

Airway obstruction, resulting from nasal cavity or pharynx blockage,leads to mouth breathing which results in postural modificationssuch as open lips, lowered tongue position, anterior and pos-teroinferior rotation of the mandible, and a change in head posture.These modifications take place in an effort to stabilize the airway. Aspreviously discussed, facial structures are modified by posturalalterations in soft tissue that produce changes in the equilibriumof pressure exerted on teeth and the facial bones (Figure 7).Additionally, during mouth breathing, muscle alterations affectmastication, deglutition and phonation because other musclesare relied upon.2

MALOCCLUSION – THE ISSUE STILL IN DEBATEIs there a cause and effect rela-tionship between adenoids, nasalobstruction and malocclusion?Dentofacial changes associatedwith nasal airway blockage havebeen described by CV Tomes in1872 as adenoid facies. Tomescoined this term based on hisbelief that enlarged adenoids werethe principle cause of airwayobstruction and resulted in notice-able dentofacial changes.7 Tomes

Fig.6

Fig.7

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reported that children, who were mouth breathers, often exhibitednarrow V-shaped dental arches10 (Figure 8). This narrow jaw is aresult of mouth breathers keeping their lips apart and theirtongue position low. The imbalance between the tongue pressure,and the muscles in the cheek, result in cheek muscles compressingthe alveolar process in the premolar region. Simultaneously, thelower jaw postures back. These simultaneous actions have beentermed the compressor theory11 (Figure 9).Tomes’ views were supported in the 1930’s by numerous leadingorthodontists. These supporting clinicians reported airwayobstruction as an important aetiologic agent in malocclusion.Rubin advocated that in order for these patients to fully beassessed they must be thoroughly evaluated by both a rhinologistand orthodontist.7 Malocclusion is the departure from the normalrelation of the teeth in the same dental arch or to teeth in theopposing arch.3

Airway obstruction, coupled with loss of lingual and palatal pressureof the tongue, produces alterations in the maxilla. The positioningof the tongue also plays an important role in mandibular devel-opment. The tongue displaced downward can lead to a retrognathicmandible; and an interposed tongue can lead to anteriorocclusal anomalies.Additionally, maxillary changes can be viewed in the transversedirection, producing a narrow face and palate often linked withcross bite; in the anteroposterior direction, producing maxillaryretrusion; and in the vertical direction causing an increase inpalatal inclination as related to the cranial base and excessiveincreases of the lower anterior face height. The most commonlyfound occlusal alterations are cross bite (posterior and/or anterior),open bite, increased over jet, and retroclination of the maxillaryand mandibular incisors.2 Mahony and Linder-Aronson’s findingswere in agreement with the significant correlation betweenchanged mode of breathing and diminished mandibular / palatalplane angle (ML/NL) found in adenodectomized children. 22

Several authors have taken the position that alleged faces arenot consistently found to be associated with adenoids, mouthbreathing, nor a particular type of malocclusion; and that thereis no cause and effect relationship between adenoids, nasalobstruction/mouth breathing and malocclusion.Proponents of this position believe that the V-shaped palate wasinherited and not acquired through mouth breathing. (Hartsooh1946) on a review of literature related to mouth breathing,

concluded that mouth breathing is not a primary etiological factorin malocclusion. Additionally, Whitaker (1911) found that in astudy of 800 children, who underwent adenoidectomy or tonsil-lectomy only 30% had dental anomalies that needed orthodonticintervention. There is some suggestion that adenoids and hyper-trophic tonsils are a consequence of a thyroid hormone deficiency.This hormone deficiency acts as a catalyst for activating theorganism’s defense mechanisms which include hypertrophy oflymphoid tissue.11 Another orthodontic clinician, Vig, took theposition that without documented total nasal obstruction, any surgeryor other treatment to improve nasal respiration, is empirical anddifficult to justify from an orthodontic point of view.7,17

NASAL RESPIRATORY EVALUATIONThe relationship of airway obstruction and dentofacial structures/malocclusion is still the subject of investigation and controversyamongst orthodontists. The correlation between functionalproblems and morphologic characteristics is yet to be solidified.Regardless of varied opinion in this area practitioners shouldobserve each patient carefully.

Suggested protocol:1. As the patient enters the room, facial and head postureshould be noted to see if the lips are closed during respiration.2. Signs of allergic rhinitis should be noted, as well as historiesof frequent colds or sinusitis.3. Assessment of family history for allergies is important.4. Sleep history should be evaluated: sleep apnoea, loud snoring,open mouth posture while asleep.5. Patient is asked to seal their lips – difficulty breathing throughnose should be noted. One nostril can be occluded and theresponse noted – same procedure on the other side. (Figure 10)The evaluation of nasal airway patency is complicated, especiallywhen the possibility exists that airways may clinically appearinadequate but be quite functional physiologically. Lip separating oran open-mouth habit is not an infallible indicator of mouthbreathing. Often complete nasal respiration is coupled with dentalconditions that cause open-mouth posture.10

ADENOID EVALUATIONNasopharyngeal space and the size of adenoids have been eval-uated using different methods of assessment: 1. Determination of the roentgenographic adenoid/nasopharyngeal

ratio (a lateral cephalometricxray);2. Flexible optic endoscopes(Figure 11);3. Acoustic rhinometry; and 4. Direct measurements duringsurgery. Direct measurements are consid-ered to be the most accurate

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because space can be assessed in three directions.12 A lateralcephalometic radiograph is an added valuable diagnostic tool forthe orthodontist in the evaluation of children with upper airwayobstructions.14 (Figure 12)

TREATMENT OF NASAL OBSTRUCTION1. Adenoidectomy with or without tonsillectomy is indicated ifhypertrophied adenoids (and tonsils) are the cause of upper airwayobstruction.7

Powered-Shaver Adenoidectomy – Adenoidectomy coupled withEndoscopic Visualization will assist in achieving adequateremoval of adenoids particularly high in the nasopharnx. Use ofthe powered-shaver technique allows for better clearance ofobstructive adenoids. The end result is more reliable restorationof nasal patency.13

2. Septal surgery (rarely indicated in the child) but may be con-sidered in the presence of a marked nasal septal deflection withimpaction. Conservative septal surgery in growing patients willnot have an adverse effect in dentofacial growth.7,18,19,20

3. Maxillary expansion (RME or SAME) – an orthodontic procedurethat widens the nasal vault.7,18

4. Cryosurgery or electrosurgery – this is a viable option forpatients with vasomotor rhinitis.7

5. Bipolar Radiofrequency Ablation (allergic rhinitis) – performedunder local anesthetic6. Inferior turbinectomy – Using powered instrumentation7. Use of nasal sprays.

CONCLUSIONThe effect of adenoids on facial expression, malocclusion andmode of breathing has been a topic of debate and investigationby practitioners in the field for the last one hundred years. Areview of the literature exposes several theories.A healthcare provider, with a practice philosophy based on pre-vention of malocclusion development, cannot ignore the earlyyears of the patient’s growth cycle. By age twelve, 90 percent offacial growth has already occurred. This is the age when manypractitioners begin orthodontic treatment.7 This is the age when80-90 percent of craniofacial growth is complete, so most for-mation and/or deformation has occurred.21 To wait until 90 percentof the abnormality has occurred, before beginning treatment, isnot consistent with a preventive philosophy. Interceptive measuresmust be initiated sooner. Early intervention requires an acceptance of

a multidisciplinary approach to total patient health. An integratedapproach to patient evaluation, diagnosis and treatment is mosteffective. Primary care physicians, dentists, allergists, otorhino-laryngologists, and orthodontists must all work together forearly prevention and management of young patients withincreased nasal airway resistance.After diagnosis, a comprehensive risk benefit analysis regardingearly intervention must be considered. Although hereditary andenvironmental factors must be considered, the universal goal isthe promotion of proper nasal respiration throughout a child’searly years of facial growth.Figure 13 shows the before and after treatment results of ayoung girl who had her adenoids removed, then underwentmaxillary expansion before full-fixed braces. She was treated asa second opinion against the removal of four premolar teeth.

Fig.13 BEFORE

Fig.13 AFTER

Fig.11 Fig.12

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REFERENCES

1. Mattar, SE, Anselmo-Lima, WT, Valera, FC and Matsumoto, MA, Skeletal and Occlusal Characteristics in Mouth-Breathing Pre-School Children, J Clin Pediatr Dent2004 28(4):315-318.2. Valera, FC, Travitzk, LV, Mattar, SE, Matsumoto, MA, Elias, AM, Anselmo-Lima, WT, Muscular, Functional and Orthodontic Changes in Pre-School Children withEnlarged Adenoids and Tonsils, Int J Pediatr Otorhinolaryngal 2003, Jul; 67(7):761-70.3. Khurana, AS, Arora, MM, Gajinder S., Relationship Between Adenoids and Malocclusion, J Indian Dental Ass., April 1986; 58:143-145.4. Pellan, P., Naso-Respiratory Impairment and Development of Dento-Skeletal, Int JO Fall; 16(3):9-11, 20055. Soxman, JA, Upper Airway Obstruction in the Pediatric Dental Patient, Gen. Dentistry July-August; 313-315, 2004.6. Ranly, DM, Craniofacial Growth, Dent Clin NA, July; 44(3):457-470, 2000.7. Rubin, RM, Effects of Nasal Airway Obstruction on Facial Growth, Ear, Nose & Throat J, May;66:44-53, 1987.8. Pistolas, PJ, Growth and Development in the Pediatric Patient, The Functional Orth. 12-22 Winter 2004/Spring 2005.9. Enlow, DH, Hans, MG, Essentials of Facial Growth; 5, 79-98, 206, 199610. Diamond, O, Tonsils and Adenoids: Why the Dilemma? Am J. Orthod., Nov. 78(5) 495-503, 1980.11. Linder-Aronson, S, Adenoids: Their Effect on the Mode of Breathing and Nasal Airflow and Their Relationship to Characteristics of the Facial Skeleton and theDentition, Acta Oto-laryng Suppl, 265: 5-132, 1970.12. Casselbrant, MC, What is Wrong in Chronic Adenoiditis/Tonsillitis Anatomical Considerations, Int J Pet. Oto 49(1):S133-S135, 1999.13. Havas, T, Lowinger, D, Obstructive Adenoid Tissue an Indication for Powered-Shaver Adenoidectomy, Arch Otolaryngol Head Neck Surg: July 2002; 128:789-791.14. Oulis, CJ, Vadiaka, GP, Ekonomides, J, Dratsa, J, The Effect of Hypertrophic Adenoids and Tonsils on the Development of Posterior Crossbite and Oral Habits, J ClinPediatr. Dent, Spring; 18(3) 197-201, 1994.15. Adams, GL, Boies, CR, Papaiella, MM, Boies’ Fundamental Oto. Philadelphia WB Sanders 1978.16. Ogura, JH, Physiologic Relationships of the Upper and Lower Airways, Ann Otgl Rhinol Laryngol, 79; 495-501, 1970.17. Vig, PS, Sarver, DM, Hall, DJ, et al, Quantitative Evaluation of Nasal Airflow in Relation to Facial Morphology, Am J Orthod, 79:263-272; 1981.18. Gary, LP, Brogan, WF, Septil Deformity Malocclusions and Rapid Maxillary Expansion, Orthodontist 4; 1-13, 1972.19. Cottle, MH, Nasal Surgery in Children, Eye, Ear, Nose and Throat Monthly; 30:32-38, 1951.20. Jennes, JL, Corrective Nasal Surgery in Children: Long Term Results, Arch Otolaryngal; 79:145-151, 1964.21. Mahony, D., Page, D. The Airway, Breathing and Orthodontics; Ortho Tribune,8-11.22. Mahony, D., Linder-Aronson, S. Effects of adenoidectomy and changed mode of breathing on incisor and molar dentoalveolar heights and anterior face heights.AOJ; 20:93-98,2004.

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o obtain unilateral chewing stability: forget aboutbalanced occlusion, it doesn’t work, but: Perfect equilibrated occlusion is essential duringparafunctional mandibular movements to prevent

unbalanced loads on the supporting alveolar ridges.1. Food is almost always chewed on one side only (Hiltebrandt,1933/35)1.2. During mastication the teeth of the denture wearer only finallycome into contact when the food load has become softened(A. Gerber, 1946).2, 3

3. Therefore the bi-lateral equilibrium is ineffective for chewingstability.4. For the unilateral chewing stability of dentures, immobility isthe key.5. Para functional contacts are occurring both day & night. In orderto distribute these forces evenly, correct centric & equilibratingcontacts are necessary.

IntroductionThe study from Suguru Kimoto et al.4 showed greater satisfaction ofthe patient wearing dentures with a lingualised occlusion concept.The article “The effect of occlusal contact localisation on thestress distribution in complete maxillary denture,5 describes theconnections which contribute to broken dentures. According tothis study, It is the form of occlusion and the positioning of theteeth in relation to the alveolar ridge which leads to an unstableload and to broken dentures.

Functional reasons causing broken denturesIncorrect positioning of posterior teethThe ideal point of pressure on the tooth is the area shown inFigure 1 with a green arrow. The chewing force is directed tothe middle of the alveolar ridge. Forces directed in a more buccaldirection progressively increase the deformation of the denture.The denture is no longer well fitting (blue area) and, in time,could initiate a crack zone in the palatal part of the denture.

Figure 1: The ideal point of pressure on the tooth is the areashown with a green arrow. The chewing force is directed to themiddle of the alveolar ridge. Forces directed in a more buccaldirection, as the red arrows show, progressively increase thedeformation of the denture.The denture is no longer well fitting (blue area) and in time,could initiate a crack zone in the palatal part of the denture.

Abrasion and centric anterior tooth contactFigure 2: The lower teeth exert pressure on the upper teeth in abuccal direction (red arrow). This multiple cyclic reaction can leadto a crack in the denture and a gap developing between thedenture and the torus palatinus.Also of importance is the contour of the teeth. By losing themain palatal cusps on the upper denture we get too much pres-sure on the buccal cusps, resulting in a crack in the palatinal partof the denture (Figure.2). Because of the inclination of the

Complete Denture StabilityDuring Chewing

Max Bosshart, CDT*

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occlusal surface, shown in figure 2, the resulting orientation ofthe forces, upwards and outwards, is increasing the deformationof the denture base. It can lead to crack formation in the denturebase and damage the alveolar bone. Usually we can easily distinguish between a functional breakageand an accidental breakage of a denture. Of course we can askthe patient what happened. For the denture construction it isimportant to know the functional origin of the break.By abrasion of the posteriors premature contacts and an anterior orcanine guidance are created. It can provoke a tilting action whichwould result in a dropping of the denture in the post dam regionleading to a lack of security. Breaking of the upper denture canalso be expected.Conclusion: Broken dentures are a good indication of instability;caused by instable positions or wrong contacts of the artificialteeth. It is in these cases that pathological damage is caused. Wecan use high-impact acrylic or just repair the denture, but, in bothcases the pathological damage will continue. The results are flabbyridges and increased bone resorbtion. The mastication efficiencyis very restricted and the patient could experience pain.To avoid these problems we need correct teeth contacts and tohave periodic re-calls every 2 years.

Tooth position and denture stabilityIn the pastMany years ago different authors discovered the problem of theunstable denture (Hiltebrandt 19331, Payne 19416, Gerber 19462). All of them proposed a spe-cific lingualised occlusal concept to solve the problem.In Europe, 1958, Albert Gerber from Zurich developed the socalled “Gerber-Method”. It is still recognised as one of the bestsystems available. 7, 8

Conventional Set-up

Figure 3: Buccal cusp contact during mastication is a handicap.Too much force is placed buccally of the ridge during workingmastication, resulting in a tilting upper denture and furthermorean un-supported direction of masticatory force.In the conventional set-up, the lower buccal cusps are on thecrest of the ridge (or more lingual) in the upper, the centralgroove is straight over the crest of the ridge (Gysi 1914/17)9.

Buccal cusp contact in a conventional set-up during masticationis a handicap. Too much force is exerted buccal of the ridge,resulting in an un-stable denture (Figure 3). With the reductionof the buccal cusps (min. 2mm) we have the mastication forcedirected over the lingual-palatal area and over the centre of theridge. This way the denture is stable during mastication (Figure4). A correlation of denture instability and progressive resorbtionof the alveolar bone4 exists. A personal observation, made by theauthor of the anatomic situation of Japanese edentulouspatients showed a significantly better situation in comparisonwith the Caucasian population. Their alveolar ridges are showingsignificantly less resorbtion in width. Also, the width of the dentalarch is distinctly greater. These characteristics are clearly favouringthe transversal denture stability. It may explain the reason, whyKumutu et al. found little or no difference in the masticationperformance of the patients. Long term results could show differentresults when the fit of the dentures deteriorate.

The Gerber SystemIn this system we put the upper vertical direction to the crest ofthe ridge (Figure 4). The denture will remain stable with theadvantage that the teeth can be placed more buccally. This notonly provides better cheek contact and more tongue space butalso stops food from slipping under the denture.

Figure 4: With the reduction of the buccal cusps (min. 2mm) wehave the mastication force in the lingual/palatal area, which isorientated almost vertically.

Sagittal StabilityThe Lower DentureThe lower denture bearing area can have a difficult shape withmany different inclined levels.Everyone knows what happens if you stand on an inclined slopeon ice or snow in Switzerland, we slide downhill without anyeffort, known as skiing! Teeth standing on the retro-molarascending part of the ridge push the denture forward duringmastication (Gysi 1917)9.Figure 5 depicts a common case. Thelast molar is positioned in the area of the ascending part of theridge & the force to the lower denture hits the inclined area. Theforce will be deflected forward and the denture slips down theslope and lifts up at the front.


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Figure 5: In a `textbook con-ventional set-up’ the lastmolar is positioned correctly;the occlusal level and curveof Spee have been observed.However, the masticatoryforce is not at 90° to theridge and the denture movesdown the sloping ridge andmoves forward & upward.

The Upper DentureCan this also happen with the upper denture? Yes!This case shows that both dentures are unstable. As the patientchews food the dentures move making it virtually impossible tomasticate. Pressure areas are pre-assigned and, with time, provokeresorbtion of the ridge. Under mastication force the upper dentureslips forward and only the patients’ lip holds the denture in position.This has a negative effect on Aesthetics, making the lips appeartensed.

Figure 6 shows in whichdirection the masticationforce on the upper jaw isdirected. As a consequenceof the poor position of theteeth, according to the Speecurve, the force is in a disad-vantageous angle to theridge and the pressure pushesthe upper denture forward

Model AnalysisAnyone building a house knows that he has to analyse theground it will be supported on. When setting up a denture weneed to do the same, we call it model-analysis. We draw on theside of the model the different zones, positive, neutral & nega-tive/unstable areas. We use different colours to get a quickanalysis of the situation (Figure 7).

Figure 7:1. The positive zones aremostly in the pre-molar area(green).The axis of the pre-molarspushes the denture, duringmastication, backwards tothe respective ridge giving a‘super’ stable situation.2. The deepest area in thelower jaw and the highest part of the upper jaw are the neutralzones (blue). In this area we set the first molars (largest teeth).

3. We can recognise on Figure 5 and 6 that the retro-molar areais critical (red). The directions of the upper and lower ridge in theposterior part are not parallel to each other. We cannot set anyteeth in this area that will be stable during masticatory function.

Posterior tooth positionThe second upper molar in Fig. 8a & 8b is 3mm out of contactto its antagonist and therefore it is not possible to chew with it.These last teeth serve only as a support to the cheeks, prevent foodslipping up or down under the denture and prevent cheek biting.10

Figure 8a and, 8b: In this set-up the second upper molar is3mm out of contact. Therefore it is not possible to chew with it.Also we can observe the large gap between upper and lowerbuccal cusps on the first molar. If sufficient space is lacking, we recommended not to place anyupper molar at all (Figure 9a and 9b)

Figure 9a and 9b: If sufficient space is lacking, we recommend-ed not to place any upper molar at all.

Balanced occlusionBut the arrangement of the teeth is still recognised as being abalanced occlusion and the molar teeth are important in Parafunctional jaw movement (Figures 10a and 10b). Apart from uni-lateral chewing stability as described above, continuous posteriorcontacts are important during non-functional tooth contacts.The even distribution of the forces over the complete upper andlower alveolar ridges will protect the natural tissues from overloador at least diminish the forces to a minimum. During all functionaland parafunctional movements, the elimination of all prematuritiesis indispensable.

Figure 8a Figure 8b

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Figures 10 and 11: Beside the static orientation of the posteri-or teeth, balanced occlusion is an absolute must to protect thesoft and hard natural tissues from local overload, occurring spe-cially during parafunctional jaw movements.

Centric relationFigure 12. Gothic archregistration of an eden-tulous case to determinecentric relation.

For instance, the regis-tration of a physiologicalcentric relation is ofmajor importance. The stability of dentures is directly related toit. It is symptomatic that upper dentures drop down irrespectiveof a perfect impression, when centric is not correct. Especially byedentulous patient cases it is difficult to obtain a reliable centricrelation. The intra oral gothic arch tracing (Figure 11) has givenmost satisfaction, especially in full denture cases, for implantwork, extensive reconstructions11 and in TMD cases12.

The articulator, an important Instrument in prosthodonticsAn incorrect centric or a straight-line commonly used articulatorcannot reproduce an Immediate side shift, a Fischer Angle or acorrect protrusive movement. Lateral movements, simulatedwithout an ISS produce too steep buccal facets on the lowermolars (hyper-balances)13. The Fischer-Angle is due to the transversalangulations of the TMJ (figure 13). The mandibular movementback and down occurs during swallowing and together with alateral displacement during chewing. (Gibbs Lundeen 14)

Figure 13: Frontal view of a leftCondyle. The roof shape is clearly visible.

Retrusive movementA simple test shows, if a retrusive move-ment exists. With the head in an uprightposition and by keeping the teeth slightlyclosed, incline the head backwards, aslight sliding of the lower teeth can be observed. With the condyle centred in its physiologic place (due to theform of the glenoid fossa) the retrusive movement is also oriented

downwards. There is no other way for the condyle than downbecause of the posterior wall (figure 14).

Figure 14: Sagittal view ofa TMJ. By the form of theposterior wall it is obviousthat the Retrusive move-ment must also be directeddownward.

Denture occlusion must bebalanced; the correct simulation allowing the physiologicmandibular movements is of major importance.

The Fischer angleDuring lateral movements, the roof shaped TMJ (figure 13), i.e.the medial wall, is providing, together with the condyle pathinclination, an additional guidance down of the condyle. The pure protrusive movement and the added inclination of themovement inward, are producing the so called Fischer angle.

Figure 15: This figure is acombination of two pictures.The upper picture shows theartificial fossa and the lowersecond picture a condyle. Themedial and external angula-tions of both elements arevery similar. This angle becomes of impor-tance during the simulationof the ISS. If these angles ofthe medial and the externalwall are missing, the occlusion becomes to flat. The figure 15has been composed by the transversal picture of Gerber’s firstarticulator from 1948 with the picture 13, placed just under-neath the artificial joint. It shows an amazing similarity between,the artificial and the natural elements.

Final RemarksIn order not to detract from the principles of the Gerber Systemwe have, on purpose, not gone into too many details. It is impor-tant to understand the forces during mastication and the waythey interact. (Who knows why, knows how!). Of course manyother factors are to be observed, from medical history to the veryimportant aesthetics, impression taking and many more. The method developed by Professor Gerber15 guarantees successwhen all the relevant aspects are respected. Those aspects con-tain all steps of a treatment, beginning with the first appoint-ment, continuing with the pre-prosthetic treatment, first andsecond impressions, centric registration, set-up of the teethpoviding aesthetic and static/dynamic requirements, trying-in,

Figure 10 Figure 11


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AcknowledgementsThe author’s acknowledgements go to Dr. A. Johnson, Mr. M.Boxhoorn and Mrs. A. Bruelhart for their assistance with thetranslation of this article.

* Max BosshartCenter Dental TechnologyZurichstr. 5, P.O.Box 23, CH - 8840 Einsiedeln, Switzerland.

REFERENCES1. HILTEBRANDT, C.: Die physiologischen und statischen Grundlagen der totalenProthese. Published byVita Zahnfabrik GmbH Essen; 1935.2. GERBER, A.: Die artikuläre Funktion und die Schleimhautbelastung beim Kauenvon Prothesen, Vortrag am SSO-Kongress in Lugano, 1946.3. GERBER, A.: Beiträge zur Technologie in der totalen Prothetik I & II. Quintessenzder Zahntechnik12/ 1976; 11-21 & 3/1977; 12-21. Quintessenz Verlags GmbHBerlin. As well pblished 1977 by Quintessenz Chicago in english language.4. KIMOTO, S., Gunji, A.; YAMAKAVA, A.; AJIRO H., KANNO, K., SHINOMIYA, M.,KAWARA, M., KOBAYASHI, K.: Prospective Clinical Trial Compairing LingualizedOcclusion to Bilateral Balanced Occlusion in Complete Dentures: A Pilot Study.Quintessence Publishing Co. Inc., Volume 19, Number 1, 2006; 103-1095. ATES, M., CILINGIR, A., SÜLÜN, T., SÜNBULÖOGLU, E. BOZDAG, E.: The effectof occlusal contact localisation on the stress distribution in complete maxillary den-ture. Journal of Oral Rehabilitation, 2006 33; 509-513. Blackwell Publishing Ltd.;Oxford6. PAYNE S.H.: A posterior set-up to meet individual requirements, >Dent.Dig.1941,47: 20-22 7. GERBER, A.: Okklusion und Artikulation in der Prothetik; 1960. Published byCondylator Service; Zurich.8. GERBER, A.: Progress in full denture prosthesis. Int. Dental Journal 2/1957; 325. 9. GYSI, A.: Montage d'Appareils avec les Dents Anatoform et les Blocs Gysi,12.7.1917; S. 28. De Trey & Co. Ltd. (A. Gysi, Sammelband III); Londres. 10. BOSSHART, M.: Funktion des zweiten Molaren. Das Dental Labor, Heft 6/2007(853-854); München.11. GOBERT, B.: Variations cliniques implantaires avec l’Enregistrement Intra-OralGerber. Revue Implantologie, Mai 2006; 39-46. A. Girot, Megève France.12. GERBER, A.; STEINHARDT G.: Dental Occlusion and Temporomandibular Joint,1989. Quintessence Publishing Co. Chicago.13. GERBER, A.: Condylator Modell 4. Der Zahntechniker r. 6, 1959; 2 -19; Schw.Zanhtenchnikervereinigung, Zürich.14 GIBBS, C., LUNDEEN, C., MAHAN, P., Fujimoto, J.: Chewing movements in rela-tion to border movements at the first molar. J Prosth. Dent. 1981: 46(12); 308-322.Mosby (Elsrevier, Amsterdam).15 HAMPSON, E.L.; M.S.D., F.D.S.; ASKEW, P.A., B.D.S., F.D.S.; TANNER, A.N.,B.D.S.; WHITE, G.E.: A technique for constructing full dentures using the Gerberarticulator and Condyloform teeth (I and II). Quintessence International 4 and 5,1973 (45 – 54, and 45 – 51); Chcago/Berlin. 16. GEERING; A., KUNDERT, M., KELSEY, Ch.: Complete Denture and OverdentureProsthetics. Thieme Medical Publishers, Inc., New York. 1993

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Hydrogen peroxide bleaching:Effect of various concentrations on mercury and other metal ions release from admixed and spherical dental amalgam

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AbstractObjectives: the aim of this study was to determine the effect ofdifferent Hydrogen Peroxide (HP) concentrations on mercury andother metal ions release from admixed and spherical dentalamalgam.Method and materials: Dental amalgam discs were preparedfrom GS.80 and Lojic+ alloys (n=25 of each alloy) according tomanufacturer's instructions in stainless steel moulds (10mmdiameter and 2mm thickness). The discs were divided into fiveequal groups for each alloy. Each group was immersed in 20 mlof 38%, 24%, 10%, or 3% HP solution for 24 h at 37oC with0% (distilled water) as control. Following immersion procedure,solutions were taken for metal ion release determination (Hg,Ag, Sn and Cu) using inductively coupled plasma mass spectrometry(ICP-MS). Statistical analysis was conducted using one and twoway ANOVA tests to determine significance of differencesbetween test groups. Bonferroni Post Hoc test was conductedfor multiple comparisons.Results: Metal ion release for the elements (Hg, Ag, Sn and Cu)increased with exposure to increasing concentrations of HP for bothGS.80 and Lojic+ amalgam alloys. The differences in concentrationof metal ions released after treatment with 0% (control), 3%,10%, 24% or 38% HP were statistically significant (p < 0.05). Conclusion: Metal ions (Hg, Ag, Cu and Sn) were released fromdental amalgam following treatment with all HP concentrations.Metal ion release increased with increasing HP concentration. Evenwith exposure of dental amalgam to relatively high HP concentration(38%), released Hg did not exceed the maximum acceptable limit.

Keywords: Hydrogen Peroxide, bleaching, metal ion release,dental amalgam

IntroductionNowadays, the increased esthetic demand by most patients hasresulted in an increase in the usage of bleaching agents towhiten discolored teeth.1-3 Bleaching of discolored vital and non-vitalteeth including both in-office and at-home techniques has along and successful history.4,5 Home bleaching has attracted the

interest of patients due to its high success rates and ease ofuse.6,7 In this procedure, patients apply bleaching agents, most ofwhich contain low concentrations of hydrogen peroxide (3% to 7%)or carbamide peroxide (10% to 22%), to their teeth in custom-fittedtrays for a few hours per day.8,9 Over the past few years, in-officebleaching products employing the use of strong oxidizing agentup to 38% hydrogen peroxide have been used.10 The advantagesare that treatment is totally under the dentist’s control, the softtissues are generally protected from the process and it has thepotential for quick bleaching.3,11 Very often in the daily clinicalpractice, restorations exist beside or even inside the teeth thatare planned to be bleached. Some clinicians express concernabout the effect of these agents on teeth and dental restorativematerials.12,13 The influence of various bleaching agents on physicalproperties, surface morphology and color of different restorativematerials, has been investigated in several in vitro-studies simu-lating the clinical situation as closely as possible. In those studies,home-bleaching products (10–16% carbamide peroxide) weregenerally used within a 2–6 weeks bleaching simulation withapplication intervals of 4–8 h per day. Bleaching products forin-office-application (30–38% hydrogen or carbamide peroxide)were applied at treatment intervals of 15–60 min (as recommendedby the manufacturers).14 The results of these studies were con-troversial. Some reports in the dental literature have suggestedthat bleaching agents may have adverse effects on the physicalproperties of dental restorative materials.15-20 Other investigationsrevealed no significant change in enamel or existing restorationphysical properties due to bleaching agents.12,20-24 Moreover,some studies reported increase in enamel or composite resin surfacehardness following bleaching.25,26 Regarding dental amalgam,some in vitro studies have reported a significant increase in mer-cury release as a result of treatment with peroxides compared tocontrol treatments.27-29 While there was also a relatively recentreport that found carbamide peroxide bleaching to have no sig-nificant effect on dental amalgam.30 This obvious and still lastingcontroversy means that the effect of oxidizing bleaching agentson dental amalgam still remains a source of concern. Therefore,the aim of this study was to investigate the effect of hydrogen

Neveen M. Ayad, PhD

Lecturer of Dental Biomaterials, Dental Biomaterials Department, Faculty of Dentistry, Mansoura University, Mansoura, Egypt.e-mail: [email protected]

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peroxide bleaching agent in different concentrations includingrecently used high concentrations on metal ion release fromdental amalgam. The working hypothesis was that high concen-trations of hydrogen peroxide bleaching may result in release ofmercury from dental amalgam that may exceed the maximumacceptable limit of daily intake.

Method and materialsTwo high copper dental amalgam alloys were selected for thisstudy, an admixed one: GS.80 (Southern Dental Industries,Australia). The composition of this alloy is 40 Ag, 31.3 Sn, and28.7 Cu (% w/w). It is mixed at an alloy to mercury ratio of 1:0.92 (w/w). The other was a spherical alloy: Lojic+ (SouthernDental Industries, Australia). The composition of this alloy is 60.1Ag, 28.05 Sn, 11.8 Cu, and 0.05 Pt (% w/w). It is mixed at analloy to mercury ratio of 1: 0.67 (w/w). Both alloys were suppliedas capsules that were activated according to manufacturer’sinstructions for 5 sec. using a mechanical amalgamator, (De Trey,Hallam Dental Ltd, England). Amalgam Discs (n=25) for eachalloy type were prepared in split stainless steel moulds (10mmdiameter x 2mm thickness), and allowed to fully set for 24 h. Thediscs were then polished using silicone carbide paper (Grit num-ber 800). A 40% HP solution, (Sigma Chemical Co. St. Louis,MO, USA) was diluted to obtain 3%, 10%, 24% as well as 38%HP solutions with 0% (distilled water) as the control. The 50amalgam discs were divided into 10 equal groups, (5 discs each).Each of the 5 discs in a group was individually immersed in 0%,3%, 10%, 24% or 38% HP solution (20ml) for 24 h at 37oC cre-ating 5 samples of each solution. Each disc was placed in atapered centrifuge tube, with all surfaces exposed to the partic-ular HP concentration in that tube. All the 50 solutions sampleswere analyzed by inductively coupled plasma-mass spectrometry(ICP-MS, Agilent 4500). All ion release samples were acidifiedwith 200 μl of nitric acid (for Ag determination) and hydrochlo-ric acid (for all other ions).30 For each analysis, the instrumentperformed five measurements and the mean values were calcu-lated for each element. A two-way ANOVA was conducted, fol-lowed by a one-way ANOVA and Bonferroni Post Hoc test formultiple comparisons between solutions of different concentra-tions for each element.

ResultsThe relationships between metal ion release from both GS.80and Lojic+ amalgam alloys and HP concentration are shown inFig. 1& 2 respectively. Values for the mean and standard devia-tion of metal ion release data for mercury, silver, copper and tinfrom both GS.80 and Lojic+ are shown in Table 1, at 0%, 3%,10%, 24% and 38% HP concentrations. Metal ion releaseincreased with increasing hydrogen peroxide concentration forall elements for both amalgam alloys. For GS.80, the highest ionreleases were those for mercury followed closely by tin then cop-per and finally silver. For Lojic+, the highest ion releases were

those for mercury followed closely by silver then tin and finallycopper. Table 2 demonstrates the F and p-values for the one-wayANOVA between test groups for each element. Bonferroni mul-tiple comparison revealed that the difference in metal ion releasebetween 0% HP (control) and all other concentrations (3%,10%, 24% and 38%) was statistically significant (p < 0.05) forall elements.

DiscussionThe experimental design in the current study was decided tocover a relatively wide range of HP concentrations that are avail-able in the dental market including both at home and in-officeproducts (3%-38%). Using two kinds of dental amalgam alloyswas suggested so that the study includes both spherical andadmixed types of dental amalgam so conclusions can, to someextent, be generalized. Comparing between the amounts ofmercury or other metal ions released from the tested alloys afterexposure to HP bleaching was not in the scope of this study.Although this study provides data about the amounts released ofHg, Ag, Sn and Cu from dental amalgam after exposure to HPbleaching, the focus will be on mercury during discussing resultsas it is known to be the most hazardous to health. The WorldHealth Organization (WHO) guideline for maximum intake ofmercury is 40 mg/day.31 From the literature, it has been reportedthat the release of metal ions from restorations is time depend-ent and proportional to the surface area of the restoration.32 Thequantity of mercury released from dental amalgam after bleach-ing as reported in scientific journals varied considerably.Hummert et al.28 found mercury release values from dental amal-gam exposed to bleaching agents to be in the range of 0.014 -0.020 μg/mm2 and 0.001 μg/mm2 for dental amalgam exposedto saline (control). Mackert and Berglund33 found that the rate ofmercury release from amalgam to be in the average of 0.014 -0.016 μg/mm2 calculated from six different in vivo studies.Rotstein et al.29 reported a concentration of 0.6 – 4.24 μg/mm2

of mercury released from amalgam samples after 48 h of 10%CP bleaching. This data suggests high metal ion release, mainlydue to the use of aggressive test procedures along with the useof unpolished samples. This is in contrast to the in vivo situationwhere the amalgam restoration is ideally polished and it is

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known that peroxide levels within bleaching products are depletedduring use34. In a further study by Rotstein et al.,35 the amount ofmercury released from amalgams treated with 10% CP was verysimilar to that released by 10% HP. Al-Salehi et al. 30 found that10% CP bleaching gel did not significantly enhance metal ionrelease from dental amalgam. In the present study, application ofhydrogen peroxide bleaching agent in different concentrationshas resulted in metal ion release (Hg, Ag, Cu and Sn) from allsamples of both GS.80 and Lojic+ alloys. For all the elements, ionrelease increased with increasing HP concentrations, with mercuryrelease consistently being the highest (Fig. 1, 2), (Table 1). Thep-values for the one-way ANOVA and Bonferroni Post Hocrevealed that the difference in metal ion release between 0% HP(control) and all other concentrations (3%, 10%, 24% and38%) was statistically significant (p < 0.05) for all elements. Asregards to GS.80, of the four elements reported, mercury and tinwere more responsive to changes in HP concentration exhibitinga fairly linear relationship between ion release and HP concentration(Fig. 1). The ion release data for copper and silver followed to agreat extent a similar trend especially at low HP concentrations.For Lojic+, mercury and silver were more responsive to changesin HP concentration, followed by tin while copper showed theleast affection by changes in HP concentration. The calculatedamounts of mercury release from a GS.80 sample were 29.69,24.2, 15.24 and 5.44 μg/ day and from a Lojic+ sample were27.92, 20.86, 15.7 and 5.72 μg/ day for 38%, 24%, 10% and3% HP concentrations, respectively. The total surface area of thecylindrical amalgam disc was 220 mm2, therefore the averagemercury release per unit area of a GS.80 sample was 0.13, 0.11,0.07 and 0.02 μg/ mm2, and from a Lojic+ sample was 0.13,0.09, 0.07 and 0.03 μg/ mm2 over a 24 h period / unit area ofthe surface exposed to 38%, 24%, 10% and 3% HP concentrations,

respectively. Assuming the area of a typical restoration in themouth is 5mm x 5mm approximately, based on these data, a singleGS.80 restoration will release on average 3.37, 2.75, 1.7 and 0.6μg/ day, and Lojic+ restoration will release 3.17, 2.37, 1.78 and0.65 μg/ day, at 38%, 24%, 10% and 3% HP concentrations,respectively. Clearly, to exceed WHO’ s maximum acceptableintake of 40 mg/day would require mercury release from 11, 14,23 and 66 GS.80 restorations and 12, 16, 22 and 61 Lojic+restorations when treated with 38%, 24%, 10% and 3% HPconcentrations, respectively. It is therefore unlikely that mercuryrelease from amalgam following contact with tooth bleachingagents containing up to 38 % HP constitutes a hazard to health. One of the limitations of this in vitro study is that the bleachingagent was kept in contact with dental amalgam without thedilution effect of saliva. However, in the oral cavity, it wouldrequire a longer period of time for metal ions released fromamalgam restorations to reach the levels obtained in the resultsof this study.

ConclusionWithin the limitations of this study, the following conclusionscan be obtained:1. Metal ions (Hg, Ag, Cu and Sn) were released from dentalamalgam following treatment with all HP concentrations.2. The amount of ion release for all elements increased withincreasing HP concentration and was statistically significant com-pared to control treatment (p < 0.05).3. Although mercury release from amalgam exposed to bleachingagents did not exceed the maximum acceptable limit interna-tionally, highly concentrated bleaching agents should be availableonly to dental professionals and they should be closely monitoredto ensure that no new hazards present themselves in the future.

0% HPMean(SD)

GS.803.3(0.57)0.09(0.02)2.6(0.18)6.23(0.37)

Lojic+2.9(0.33)0.05(0.02)1.03(0.04)8.77(0.06)

Hg (μg/l)Ag (μg/l)Sn (μg/l)Cu (μg/l)

3% HPMean(SD)

GS.80272(17.8)77.6(7.1)180.2(9.7)85(12.1)

Lojic+286(10.8)125.3(5.0)43.8(6.2)49(4.5)

10% HPMean(SD)

GS.80762(26.8)93.5(6.5)532(39.3)125(14.9)

Lojic+785.1(9.9)562(7.3)

198.2(10.0)76.2(2.5)

24% HPMean(SD)

GS.801210(35.3)179.2(15.9)896.4(41.3)212.2(13.5)

Lojic+1043(12.2)824.5(7.1)487(9.0)174(6.6)

24% HPMean(SD)

GS.801210(35.3)179.2(15.9)896.4(41.3)212.2(13.5)

Lojic+1043(12.2)824.5(7.1)487(9.0)174(6.6)

Table 1. Means and standard deviations for metal ion release

GS.80F-value3000.2225.5

1623.4269.8

p-value0.0000.0000.0000.000

HgAgSnCu

Lojic+F-value

15688.032769.87111.41656.9

p-value0.0000.0000.0000.000

Table 2: F & p-values for the one-way ANOVA between groups (0%, 3%,10%, 24%, 38%)

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REFERENCES1. Sulieman M, Addy M, Macdonald E, Rees JS. The bleaching depth of a 35% hydrogen perox-ide-based in-office product: a study in vitro. Journal of Dentistry 2005;33(1):33–40.2. Fasanaro TS. Bleaching teeth: history, chemicals and methods used for common tooth discol-orations. J Esthet Dent 1992;4:71-78.3. McEvoy SA. Chemical agents for removing intrinsic stains from vital teeth. II. Current tech-niques and their application. Quintessence International 1989;20:379–84.4. Attin T, Paque F, Ajam F, Lennon AM. Review of the current status of tooth whitening with thewalking bleach technique. Int Endod J 2003;36:313—29. 5. Haywood VB. History, safety, and effectiveness of current bleaching techniques and applica-tions of the nightguard vital bleaching technique. Quintessence Int 1992;23:471—88.6. Leonard RH Jr. Long-term treatment results with nightguard vital bleaching. Compend ContinEduc Dent 2003 Apr;24:364-374.7. Karpinia KA, Magnusson I, Sagel PA, Zhou X, Gerlach RW. Vital bleaching with two at-homeprofessional systems. Am J Dent. 2002 Sep;15 Spec:13A-18A.8. Haywood VB. Current status of nightguard vital bleaching. Compend Contin Educ Dent Suppl2000;28:S10-17.9. Leonard RH, Sharma A, Haywood VB. Use of different concentrations of carbamide peroxidefor bleaching teeth: an in vitro study. Quintessence International 1998;29(8):503–7.10. Polydorou O, Monting JS, Hellwig E, Auschill TM. Effect of in-office tooth bleaching on themicrohardness of six dental esthetic restorative materials. Dental Materials 2007;23:153–8.11. Auschill TM, Hellwig E, Schmidale S, Sculean A, Arweiler NB. Efficacy, side-effects andpatients’ acceptance of different bleaching techniques (OTC, in-office, at-home). Oper Dent2005;30:156–63.12. Swift Jr EJ, Perdigao J. Effects of bleaching on teeth and restorations. CompendiumContinuing Educ Dentistry 1998;19:815–20.13. Swift Jr EJ. Restorative considerations with vital tooth bleaching. J Am Dent Assoc1997;128(Suppl):60S—4S.14. Attin T, Hannig C, Wiegand A, Attin R. Effect of bleaching on restorative materials andrestorations—a systematic review. Dental Materials 2004;20:852–61.15. Lee JH, Kim HI, Kim KH, Kwon YH. Effect of bleaching agents on the fluoride release andmicrohardness of dental materials. Journal of Biomedical Materials Research 2002;63(5):535–41.16. Jung CB, Kim HI, Kim KH, Kwon YH. Influence of 30% hydrogen peroxide bleaching on com-pomers in their surface modifications and thermal expansion. DentalMaterials Journal 2002;21(4):396–403.17. Turker SB, Biskin T. Effect of three bleaching agents on the surface properties of three differ-ent esthetic restorative materials. Journal of Prosthetic Dentistry 2003;89(5):466–73.18. Duschner H, Gotz H, White DJ, Kozak KM, Zoladz JR. Effectsof hydrogen peroxide bleachingstrip gels on dental restorative materials in vitro: surface microhardness and surface morphology.Journal of Clinical Dentistry 2004;15(4):105–11.19. Taher NM. The effect of bleaching agents on the surface hardness of tooth colored restora-tive materials. J Contemp Dent Pract 2005;15:18-26.20. Yap AU, Wattanapayungkul P. effects of in-office tooth whiteners on hardness of tooth-col-ored restoratives. Oper Dent 2002;27:137-141.21. Cullen DR, Nelson JA, Sandrik JL. Peroxide bleaches: effect on tensile strength of compositeresins. J Prosthet Dent 1993;69:247-249.22. Garcia-Godoy F, Garcia-Godoy A. Effect of bleaching gels on the surface roughness, hard-ness and micromorphologhy of composites. Gen Dent 2002;50:247-250.23. Schemehorn B, Gonzalez-Cabezas C, Joiner A. A SEM evaluation of a 6% hydrogen perox-ide tooth whitening gel on dental materials in vitro. J Dentistry 2004;32(Suppl 1):35–9.24. Mair L, Joiner A. The measurement of degradation and wear of three glass ionomers follow-ing peroxide bleaching. J Dentistry 2004;32(Suppl 1):41–5. 25. Turker SB, Biskin T. The effect of bleaching agents on the microhardness of dental aestheticrestorative materials. Journal of Oral Rehabilitation 2002;29(7):657–61.26. Campos I, Briso AL, Pimenta LA, Ambrosano G. Effects of bleaching with carbamide perox-ide gels on microhardness of restorative materials. J Esthet Restor Dent 2003;15:175-182.27. Robertello FJ, Dishman MV, Sarrett DC, Epperly AC. Effect of home bleaching products onmercury release from an admixed amalgam. American Journal of Dentistry 1999;12: 227–30.3.28. Hummert TW, Osborne JW, Norling BK, Cardens HL. Mercury in solution following exposureof various amalgams to carbamide peroxide. American Journal ofDentistry 1993;6:305–9.28. 29. Rotstein I, Dogan H, Avron Y, Shemesh H, Steinberg D.Mercury release from dental amalgamafter treatment with 10% carbamide peroxide in vitro. Oral Surgery Oral Medicine Oral PathologyOral Radiology Endodontics 2000;89:216–9.30. Al-Salehi SK, Hatton PV, Miller CA, McLeod C, Joiner A. The effect of carbamide peroxidetreatment on metal ion release from dental amalgam. Dental Materials 2006;22:948–53.31. Jones DW. Exposure or absorption and the crucial question of limits for mercury. J Can DentalAssoc 1999;65:42–6.32. Berglund A, Pohl L, Olsson S, Bergman M. Determination of the rate of release of intra-oralmercury vapour from amalgam. Journal of Dental Research 1988;67:1235–42.33. Mackert JR, Berglund A. Mercury from dental amalgam fillings: absorbed dose and potentialfor adverse health effects. Critical Reviews in Oral Biology and Medicine 1997;8: 410–36.34. Sagel PA, Odioso LL, McMillan DA, Gerlach RW. Vital tooth whitening with a novel hydrogenperoxide strip system: design, kinetics, and clinical response. Compendium Continuing EducDentistry 2000;21:S10–34.35. Rotstein I, Chaim M, Arwaz JR. Changes in surface levels ofmercury, silver, tin and copper ofdental amalgam with carbamide peroxide and hydrogen peroxide in vitro. Oral Surgery OralMedicine Oral Pathology Oral Radiology Endodontics 1997;84(4):506–9.

CALCIUM HYDROXIDE and GLASS IONOMER LINERS:

The Prevalence of Use among Prosthodontists,Pediatric and General Dentists in Different Countries.


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ABSTRACTPurpose: This survey was designed to gather most of the informationregarding the use of dental liners amongst three dental specialtiesin different countries. More so, issues and opinions have beenraised about using specific dental liners, which as the same timeother studies were against the use of the same materials makingthe decision of choosing dental liners more difficult. Collectingthis information will basically provide us with the most used dentalliners in different countries around the world.The aim of the study is to: Determine the prevalence of usingcalcium hydroxide and/or Glass ionomer, to assess the reason ofusing these two materials, and to verify the purpose of usingeach of these materials.

Amongst the selected Dentists, the Method and Materials:The survey has been conducted by distributing questionnaires tothe three dental specialties, which involves Prosthodontics,Pediatric Dentistry and General Practitioners Dentists from differentcountries which include; Kuwait, Qatar, Saudi Arabia, UAE,United Kingdom, Thailand, and various states in the UnitedStates of America. The 40 questionnaires have been randomlyallocated to each selected country by mail. The questions havealso been concentrated on the using of the dental liners, theindications of the using, and the dentist’s knowledge about dentalmaterials. Variables: The prevalence, Type of the dentition, andType of the liners. Results: The selected countries were dividedinto three regions. In the North American region, of the 104returned questionnaires, 13 dentists (12.5%) reported usingcalcium hydroxide, 59 dentists (56.7%) use glass ionomer, and32 dentists (30.8%) use both calcium hydroxide and glassionomer as dental liners. Fifty-five (55) dentists (45.9%) in theAsian region are recorded as using calcium hydroxide, 15 dentists(12.5%) use glass ionomer, 42 dentists (35%) prefer to use bothliners, and 9 dentists (7.5%) use none. In the European region,5 (7.5%) selected calcium hydroxide, 34 (51.5%) selected glass

ionomer, and 27 (40.9%) said they used both liners. A signifi-cant difference was found amongst the three groups of dental spe-cialists in the use of calcium hydroxide and/or glass ionomer. Oneway analysis of variance showed that General dentists use CH exclu-sively (33%); more than Prosthodontists (20%) and Pediatricdentists (21%), (F2=2.39; p= .093).

Furthermore, according to the results continuing educationcourses were the most commonly indicated manner for thosedentists in the North American (97.1%) and European regions(86.4%), whereas continuing education courses was the leastcommon option in the Asian region (40.8%). Conclusion: The use of GI was found to be increased, comparedto CH, as dental lining material in both North American and inEuropean regions. Required continuing education courses in theNorth American and European regions might have an influenceon the selection of dental lining materials.

INTRODUCTIONAs most of the life sciences, Dentistry has progressed remarkablyduring this century, with great success in the areas of diagnostic,prevention therapeutics and dental industries. A large number ofmaterials have been introduced into the dental fields to providean esthetical and functionally healthy tooth. Among the importantmaterials are dental liners and bases, which eliminate the post-operative complications and protect the dental pulp. In fact, no artificial material can be placed into a tooth to providebetter protection for the pulp than dentin. Basing or lining materialsdo not have properties, which can be demonstrated that ideallyduplicate those of dentin. The remaining dentin thickness fromthe pulpal extent of the cavity preparation to the pulp is the singlemost important factor, which protects the pulp from insult(Stanley, 1981). In vitro studies have shown that a 0.5mm thicknessof dentin reduces the toxicity level of a material by 75% and a 1 mmthickness of dentin by 90% (Meryon, 1988).1

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Microleakage is a common, unavoidable, clinical phenomenonby which oral fluids, ions, molecules, and bacteria penetrate thetooth/restoration interface and gain access to dentinal tubuliand pulp.4

The sealing property of a basing material is one important criteria todetermine the success or failure of a base. Cox et. al. stated thatbacterial leakage under restorations is the primary cause of pulpalirritation. They further indicated that healing of dental pulpexposures is not dependent on the effect of a particular type ofmedicament, but on the capacity of the capping material to preventbacterial leakage.2

The proposed benefits for using adhesive liners under amalgamsare to decrease microleakage and temperature sensitivity, to provideimproved retention and strengthening of adjacent tooth structure.Researchers have sought to find a cavity sealer that could provideimproved performance over varnish, since more studies haverevealed that varnishes reduce but do not eliminate microleakagearound amalgam restorations (Pashly & Depew, 1986; Fitchie &others 1990). Cavity liners when placed with minimal thickness, usually lessthan 0.5 mm act as a cavity sealers and provide expanded benefits,such as fluoride release, adhesion to tooth structure, antibacterialaction and promotes a healthy pulp (McCoy, 1995).Both calcium hydroxide and glass ionomer cements become liningmaterials of choice: calcium hydroxide because of its ease ofhandling and its excellent pulpal response. And glass ionomerbecause of its ability to adhere to tooth structure, its potential tobe etched and reliably bonded, and its apparent ability to reducepostoperative sensitivity when used as a base under posteriorcomposite resins.

Calcium hydroxide:It has long been used as a base/liner because of its pulpalcompatibility and purported ability to stimulate reparativedentin formation with direct pulpal contact (Stanley, 1981).However, research has shown that not all formulation ofCa(OH)2 have a stimulatory effect on human pulpoblasts (Hanks,Bergenholtz & Kim, 1983). Conventional formulation of Calciumhydroxide demonstrated poor physical properties (Farah & others,1983; Craig, 1989). High solubility may result in contaminationof bonding agents and increased marginal leakage (Krejci & Lutz,1990), as well as softening or material loss poorly sealed restorations(Brannstrom, 1984; Pereira, Manfio & Franco, 1990). Visible-light-activated calcium hydroxide overcomes most of these deficienciesand exhibits improved physical properties (Tam & others, 1989)and significantly reduced solubility (Craig, 1989).

Glass Ionomer:The invention of glass ionomer cement as a dental material wasfirst reported by Wilson and Kent (1972). Due to their chemicalnature, these materials are able to adhere to enamel and dentinsurfaces.5 Glass ionomer has been utilized as a cavity liner in an

attempt to take advantage of two highly desirable properties:chemical bond to tooth structure and fluoride release (Craig,1989). Although fluoride release from glass ionomer decreaseswith time (Olsen & others, 1989), sustained release has beendemonstrated (Mitra, 1991) with corresponding uptake intoadjacent tooth structure (Geiger & Weiner, 1993). Pulpalresponse to both visible-light-activated and a conventional glassionomer formulation have been shown to be quite favorable(Hosada & others, 1991; Gaintantzopoulou, Willis & Kafrawy,1994), probably due to glass ionomer’s ability to decrease bacterialpenetration (Heys & Fitzgerald, 1991). In addition, glass ionomerhas been shown to reduce microleakage when placed underamalgam restorations (Arcoria, Fisher & Wagner, 1991).Conventional glass ionomer is relatively soluble in an acidic envi-ronment and it’s susceptible to rapid surface deterioration whensubjected to acid etching (Smith, 1988).The aim of this survey was to determine the prevalence and theindications of using Calcium hydroxide and/or Glass ionomeramong three dental specialties in seven different countriesaround the world.

METHOD AND MATERIALSThis survey was conducted during a 6-month period by distributingquestionnaires, (Index - I), to the three dental specialties, whichinvolve Prosthodontics, Pediatric Dentists and GeneralPractitioner Dentists in different countries including: Qatar, SaudiArabia, United Arab Emirate, United Kingdom, Thailand,Switzerland and five states from the Unites States of Americaincluding; Massachusetts, Illinois, California, Texas, and Florida.The 300 questionnaires were rationed to the selected sevencountries. 40 questionnaires were randomly allocated to eachcountry including Qatar, Saudi Arabia, United Arab Emirates,United Kingdom, Switzerland and Thailand. At the same time,30 questionnaires were sent to the selected five states in theUnited States of America. The envelopes were sent by airmail.Stamped return envelopes were included. The questionnaire is composed of 12 questions. These questionsinclude the type of dental liners, the indication for using dentalliners, the type of the dentition (primary and/or permanent)which they usually apply these materials to, the kind of the curingmethod, the dentist’s knowledge and the dentist’s satisfactionover the chosen dental liner.

RESULTSThe selected countries were divided into three regions: the NorthAmerican region (Massachusetts, Illinois, California, Texas, andFlorida), the European region (Switzerland and United Kingdom),and the Asian region (Qatar, United Arab Emirates (UAE), SaudiArabia and Thailand). From the selected countries in theseregions, 291 completed questionnaires were submitted by 83Prosthodontists (28.5%), 105 Pediatric Dentists (36%), and 103General Dentists (35.5%).

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Through the questionnaire, respondents had been asked to indicatethe dental liners they used during their dental procedures. Theywere given four options from which to choose: calcium hydrox-ide (CH), glass ionomer (GI), both liners, and none. In the North American region, of the 104 returned questionnaires,13 dentists (12.5%) reported using calcium hydroxide, 59(56.7%) dentists use glass ionomer, and 32 dentists (30.8%) useboth calcium hydroxide and glass ionomer as dental liners. Fifty-five (55) dentists (45.9%) in the Asian region are recorded asusing calcium hydroxide, 15 dentists (12.5%) use glass ionomer,42 dentists (35%) prefer to use both liners, and 9 dentists (7.5%)use none. In the European region, 5 (7.5%) selected calciumhydroxide, 34 (51.5%) selected glass ionomer, and 27 (40.9%)said they used both liners. One-way analysis of variance revealed significant differencesbetween regions in the use of calcium hydroxide (F2=26.49;p< .001), and of glass ionomer. (F2= 31.83; p< .001). (Figure 1)

Among all of the selected countries the variation in use of eithercalcium hydroxide or glass ionomer was clearly apparent. In theUnited Arab Emirates 17 of 36 responding dentists (47.2%) usecalcium hydroxide and 5 dentists only use glass ionomer(13.8%). According to the 38 responding dentists from Qatar,glass ionomer has not been chosen as a single dental liner,whereas, 27 of 38 (71%) dentists indicated that they use calciumhydroxide. Much the same seems to occur in Saudi Arabia. Ofthe 25 respondents, 8 dentists (32%) used calcium hydroxideand 4 dentists (16%) used glass ionomer as a liner. Thai dentistswere slightly different than Middle Eastern dentists in choosingdental liners. Three (14.2%) of 21 responding dentists use calciumhydroxide and 6 dentists (28.5%) use glass ionomer. All theremaining dentists had in common the practice of using bothcalcium hydroxide and glass ionomer as liners. In contrast, the selection of dental liners among dentists in theUnited Kingdom and Switzerland differed remarkably from thepreviously mentioned countries. In the United Kingdom, 2 of38 responding dentists (5.2%) selected calcium hydroxide, 18dentists (47.3) selected glass ionomer, and 18 (47.3%) dentistsselected both liners. Only 3 (10.7%) of the responding 28 Swissdentists selected calcium hydroxide, 16 (57.1%) selected glassionomer, and 9 (32.1%) dentists selected both liners. One-wayanalysis of variance demonstrated significant differencesbetween countries in the use of calcium hydroxide only

(F6=15.49; p< .001), and glass ionomer only (F6= 11.88; p<.001). (Figure 2)

A significant difference was also found amongst the threegroups of dental specialists in the use of calcium hydroxideand/or glass ionomer. The One way analysis of variance showedthat General dentists use CH exclusively (33%); more thanProsthodontists (20%) and Pediatric Dentists (21%), (F2=2.39;p= .093). The dentists had also been asked whether they had a privatepractice or worked in another type of dental facility. From theresponse to that question, in all the selected countries, anunpaired t-test showed that dentists who did not work in privatepractice used CH exclusively (34%) and twice as frequently asthe dentists who worked in private practices (14%) (t286=3.93;p< .001). This contrasted with the responses of those dentistswho work in private practices since these dentists use GI exclusively(50%) and twice as often as dentists who do not work in privatepractices (28%) (t286=3.92; p< .001).Sample subjects had also been asked about the indications forusing dental liners. Five optional indications were provided:direct pulp capping, indirect pulp capping, under amalgamrestorations, under composite restorations, and whenever needed.The indications from each region were analyzed accordingly. Themajority of the dentists in all three regions use dental linerswhenever it is needed as follows: 75.8% for the Asian region,80.3% for the European region, and 80.9% for North Americanregion. (Figures 3 to 5 show the prevalence of the liner’s indicationfor each region.)

Figure 2: The prevalence of using dental liners among all countries

Figure 3: The indications of using dental liners among Asia region

Figure 4: The indications of using dental liners among Europe region

Figure 1: The prevalence of using dental liners among three regions



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Our survey was also sought to determine, among countries thetype of dentition that would be indicated for the dental liners.For this purpose, an unpaired t-test has been used and it showedthat while there was no significant difference in the type ofdentition, dentists who, for permanent teeth, use GI only (56%)are significantly different than dentists who use CH only (16%)(t287=3.16; p= .002).How the dentists had acquired information about liners andtheir use had been identified through the survey. Three means ofdevelopment were provided for selection: continuing educationcourses, dental journals, and other sources. There was a signif-icant difference amongst the three regions in those who hadparticipated in continuing education courses (F2=70.77;p< .001)(Figures 6-8).

According to the results, continuing education courses were themost commonly indicated manner for those dentists in the NorthAmerican (97.1%) and European regions (86.4%), whereascontinuing education courses was the least common option inthe Asian region (40.8%). One-way analysis of variance showed an interesting significant

difference between dentists who attend continuing educationcourses and the use of calcium hydroxide only, (F1=12.88; p< .001),and dentists who attend continuing education courses and theuse of glass ionomer only (F1=18.72; p< .001). This analysisshowed a contrasting correlation between attending continuingeducation courses and the use of calcium hydroxide only. In thatrelationship the study found that 76.9% of the dentists, whouse calcium hydroxide only, do not attend continuing educationcourses. There was also a statistical difference between dentistswho attend continuing education courses and the use of glassionomer 86% use glass ionomer only as a dental liner.Overall, the level of satisfaction which resulted in using the indicateddental liners was also sought and we found that 56 (19.3%) ofthe dentists are “very satisfied,” 222 (77%) are “satisfied,”whereas, 12 (4%) dentists are “somewhat unsatisfied.” No dentistselected “unsatisfied.”

DISCUSSIONThis study reflects the prevalence in the use of calcium hydroxideand/or glass ionomer among three dental specialties in sevendifferent countries. A review of literature on the use of the linersunder scrutiny offered little or nothing on the prevalence of theiruse, and thus suggested that there were no previous studies onthis subject. Several factors that might influence the usage patternof these two dental liners were also discussed. Participating dentistswere asked 12 questions in order to analyze as many influentialfactors as possible.Among the three regions, we found that calcium hydroxide isused more in the Asian region while the dentists in the NorthAmerican and European regions use glass ionomer. In agreementto our finding, a survey included 64 North American schools,which has been done by Frazier et al. have shown that glassionomer was used by 74% of the schools since calcium hydroxidewas indicated in less than 10% of the responses. According to our results, the possible reason for the differencesamong regions might be that attending continuing educationcourses is required in the North American and European regions,which might result in lack of receiving the update informationabout the dental materials. Our study revealed that 86% of the dentists who attend continuingeducation courses use glass ionomer only, as a dental liner, and76.9% of the dentists who use calcium hydroxide only do notattend these courses.Regarding glass ionomer material, in 1992 S. C. Bayne statedthat general usage of glass ionomer over 20 years indicated ahigh benefit-to-risk-ratio, and that glass ionomer is trouble-free.In further support of this, Rabchinsky J. el. al. have stated thatthose repairs in which glass-ionomer cement liners were used,there was significantly less demineralization and microleakagethan those done with calcium hydroxide liners. In 1989 Pappalardo et al. had compared glass ionomer and calciumhydroxide as dental liners, and found that GI showed the tendency

Figure 5: The indications of using dental liners among N. America region

Figure 6: The prevalence of methods used for improvement of dentist’sknowledge regarding dental liners in Asia region

Figure 7: The prevalence of methods used for improvement of dentist’sknowledge regarding dental liners in Europe region

Figure 8: The prevalence of methods used for improvement of dentist’sknowledge regarding dental liners in N. America region


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to be chemically bonded to dentin, and mechanically throughthe etching to the composite restorative materials. At the sametime, Grajower et al. had found that a wash-out of the liningwas observed for most teeth in which dycal had been presentnear the proximal tooth wall. Incipient caries formation was alsonoted in a few of his samples. These findings correspond withthe high prevalence in the use of glass ionomer in selected countriesof two regions in our study. According to our results, the prevalence in the use of calciumhydroxide was highest among general dentists compared to theother two specialties. This finding is almost similar to the studythat has been done by A. Santini who found that general den-tists’ use of calcium hydroxide, as a lining material is widespread. In the study under discussion we found that, dentists who haveprivate practice tend to use glass ionomer more than calciumhydroxide. Widstrom et al. supports the finding having foundthat glass ionomer is the most frequently used in children byprivate practitioners.

CONCLUSION• The use of GI has increased, compared to CH, as dental liningmaterial in both North American and in European regions.• Required continuing education courses in the North Americanand European regions might have an influence on the selectionof dental lining materials.

• Among all the selected countries, the indication for using GIand/or CH was not significantly different, since they all have thesame reason to for using the selected dental liners. • Dentists in private practice use glass ionomer more often thancalcium hydroxide.• General dental practitioners tend to indicate calcium hydroxidemore often than glass ionomer.

REFERENCES1. Bayne SC. Dental composites/glass ionomer: clinical reports. Review. Advances in Dental Research.Sep. 1992; 6:65-77.2. Cindy R. Rauschenberger, DDS, MS, and Eric J. Hovland, DDS, Med, MBA. Clinical Management ofCrown Fractures. Dental Clinics of North America. January 1995; V. 39. Number 1. 3. Grajower R., Bielak S., and Eidelman E. Observations on a calciumhydroxide lining in retrieved decid-uous teeth, with proximal amalgam fillings. Journal of Oral Rehabilitation. Nov. 1984; 11(6): 561-9.4. Ilana Eli, DMD, Yifat Cooper (Bril), DMD, Ariel Ben-Amar, DMD, and Ervin Weiss, DMD. AntibacterialActivity of Three Dental Liners. J Prosthod 1995; 4: 178-182.5. J. Muller, W. Horz, G. Bruckner, E. Kraft. An experimental study on the biocompatibility of liningcements based on glass ionomer as compared with calcium hydroxide. Dent Mater, January 1990;6:35-406. Kevin B. Frazier, DMD., and Ivar A. Mjor, MSD, DR ODONT. The Teaching of All_CeramicRestorations in North American Dental Schools: Materials and Techniques Employed. Journal ofEsthetic Dentistry. 1997; 9(20: 86-93. 7. Kai Chiu Chan, D.D.S., M.S., and Edward J. Swift, Jr., D.M.D. Leakage of chemical and light-curedbasing materials. J Prossthet Dent, 1989; 62:408-11.8. Pappalardo G., Cicciu D., and Galioto S. Use of G.I.C. as a cavity liner. Clinical experience.Stomatologia Mediterranea. Apr-Jun.1989; 9(2): 141-7.9. Rabchinsky J. Donly KJ. A comparison of glass ionomer cement and calcium hydroxide liners inamalgam restorations. International Journal of Periodontics & Restorative Dentistry. Aug. 1993; 13(4):378-83.10. R. J. McConnell, B.D.S., F.F.D., L. Boksman, D.D.S., B.Sc., J. K. Hunter, D.D.S., M.S., F.I.C.D., D. R.,and Gratton, D.D.S., M.S. The effect of restorative materials on the adaptation of two bases and adentin bonding agent to internal cavity walls. Quintessence International. 1986; V. 17, Number 11,703-10.11. Santini A. the diagnosis, classification and treatment of acute pulpal pain by UK general dentalpractitioners: results of a survey. Primary Dental Care. Mar. 1996; 3(1): 24-7.12. T J Hilton. Cavity Sealers, Liners, and Bases: Current Philosophies and Indications for Use. OperativeDentistry, 1996; 21, 134-146.13. Widstrom E. and Forss H. Selection of restorative materials in dental treatment of children andadults in public and private dental care in Finland. Swedish Dental Journal. 1994;18(1-2): 1-7.

INDEX - I: The Questionnaire

1) What is your specialty?Prosthodontics PedodonticsGeneral dentistry.

2) Do you work for the government?Yes No

3) Do you have your own private practice?Yes No

4) Do you work full time in your private practice?Yes No

5) How long have you been in this practice?Less than two years 2-5 yearsMore than five years

6) How would you improve your knowledge regarding the dental materials?(You may select more than one)

Continuing education courses Dental journalsOther sources

7) Are you the one who provides the dental materials for the clinic?Yes No

8) What kind of dental liners do you usually use?Calcium Hydroxide Glass ionomerBothNon of the above

9) Do you use a liners in:Permanent teeth Primary teethBoth

10) What would be your reason for using a dental liner? (You may select more than one reason)

Direct pulp capping.In-direct pulp capping.Under Amalgam restorationsUnder Composite restorations.Whenever it’s needed.

11) What kind of curing method do you usually use for the dental liners?Light cure.Conventional.

12) Which one of the following responses most closely describes your satisfactiontowards the dental liners that you are using?

Very satisfied SatisfiedSomewhat unsatisfiedUnsatisfied


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GNYDM defies the Economy's Skepticsand Achieves Another Successful Event

Total registration was enormous and Dentists

appeared in waves to continue to make the Greater

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best dental products and technology buying

event and educational forum of its kind in the

United States. Total registration in 2009 was a

record breaking 59,166. While we wel-

comed 17,710 Dentists in 2008, this year we reg-

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increase of 10%. International registration

grew from 4,889 individuals in 2008 to 5,705in 2009, a rise of 16%. Attendees traveled

from 124 countries. Even in this challenging

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event which proved to be successful for alldental professionals and the entiredental trade.

Dr. Clifford Salm, General Chairman of the Greater New York Dental Meeting

Dr. Georges Freedman lecturing on bonding resins

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Dean Lonnie Norris, Executive V.P. Michael Alfano and Dr. Tony Dib during the Monday Celebrity Luncheon

Dr. Tony Dib, Dean Lonnie Norris, Executive V.P. Michael Alfano and DeanCharles Bertolami

Dr. Salm, Mrs. Katz and Dr. Lieb during the Hands-on training usinginjectible Botox and Dermal fillers

Pr. Jon Suzuki during his "Free gingival graft workshop" Dr. Joe Massad and Dr. Richard June in the impression workshop

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The International Academy for Dental-Facial Esthetics New Fellow ceremony in New York

Left to right: Dr. George Freedman, Dr. Irwin Smigel, Dr. Tony Dib, Dr. David Hoexter, and Dr. Joe Massad at the Induction Ceremony


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DOES YOUR PATIENT SUFFER FROM

DRY MOUTH?What is dry mouth?We can all suffer from dry mouth at some point, for example, ifwe are nervous or stressed. So most of us are familiar with thefeeling of not having enough saliva in our mouth to keep itmoist and lubricated. For some people, however, dry mouth canbe a regular problem. As we get older we are more likely toexperience dry mouth, but it’s also a problem that can affectpeople from their 30s onwards.

What causes dry mouth?Dry mouth occurs when the salivary glands stop working effec-tively. Medicines are known to cause over 60% of dry mouthcases, with more than 400 different medications linked to drymouth. The number of medicines a patient takes is also directlyrelated to the likelihood of experiencing dry mouth. Health con-ditions are also linked to dry mouth, such as diabetes orSjögren’s syndrome. People who smoke, who are pregnant,stressed, anxious or dehydrated are also more likely to have drymouth.

What are the symptoms?The symptoms of dry mouth can include:• difficulty in eating, especially with dry foods, such as • cereals or crackers• difficulty in swallowing and speaking• a burning sensation in the mouth• taste disturbances• painful tongue• dry, cracked, painful lips• bad breath• persistent difficulty in wearing dentures• feeling thirsty, especially at night• dry, rough tongue.Sometimes the amount of saliva a person produces may bereduced by up to 50% before these symptoms are noticed.These symptoms can sometimes have a profound effect on selfconfidence.

Does dry mouth cause other problems?Saliva plays a very important protective role in the body. It notonly keeps our mouth moist, it also helps to protect our teethfrom decay, helps to prevent infections and helps to heal sores inthe mouth.

Are your patients dry mouth sufferers?• Do they have difficulty swallowing certain foods?• Does their mouth feel dry when eating a meal?• Do they need to sip liquids to help swallow dry foods?• Are they taking multiple medicines?If a patient answered yes to any of these, he/she may have dry mouth.

Products to ease dry mouthThe Biotène system is specifically designed to treat dry mouth.The different products in the Biotène system allow you to choosethe ones that best meet your lifestyle and dry mouth needs:• 1 product specifically designed to help relieve your dry mouth: • the gel provides long lasting relief• 2 products to help maintain healthy teeth and prevent tooth • decay in people with dry mouth: a toothpaste, with fluoride, • and mouthwash which can be used twice a day in place of the • usual products. These are designed to be gentle on your • mouth as they are alcohol-free and don’t contain harsh • detergents.

Biotène supplements the make-up of normal saliva to replenishdry mouths. It has a patented enzyme formulation that:• helps supplement saliva’s natural defences• helps maintain the oral environment to provide protection • against dry mouth• helps supplement saliva’s natural antibacterial • system - weakened in a dry mouth.Biotène’s gentle formulation is also free from alcohol and harshdetergents.

What else can a patient do to manage dry mouth?• Sip water or sugar-free drinks often• Avoid drinks which dry out the mouth, such as caffeine-containing• drinks (coffee, tea, some fizzy drinks) and alcohol• Chew sugar-free gums or sweets to stimulate saliva flow• Avoid tobacco as this has a drying effect• Use a humidifier at night to keep the air full of moisture.

To help keep healthy teeth and avoid tooth decay:• Brush teeth with a soft toothbrush after meals and at bedtime• Floss teeth gently every day. If there is bleeding from gums • when flossing, this could be a sign of gum disease. • Use an SLS-free, fluoride toothpaste, like Biotène, with its • gentle formulation• Avoid alcohol-containing mouthwashes as these can dry • out the mouth• Avoid sweet, sugary foods• Visit the dentist at least twice a year for a check-up.

It is indeed a source of great pleasure to welcome all ouresteemed guests in the Egyptian Dental Association’s 14th inter-national Dental Congress.The present congress is again held during a period of great tur-moil where our region is still living through and undergoinggreat upheavals.It is however, through such human interactions such as thisCongress that people of different backgrounds are broughttogether and made to better understand each other, which weare sure will ultimately lead to better understanding between usall, as well as to better relations among all our nations. It isindeed one of the major benefits of scientific exchange to bringdifferent people from all over the world together where theymay share common goals and objectives.

May we wish all our guests a pleasant and enjoyable stayamongst us, and we sincerely hope that you may fully enjoy thescientific and social programmes we have prepared for you.Thank you very much indeed for joining us and for contributingto the success of our meeting, and we hope to see you againwith us many more times in future congresses.President of the congress, Prof. Hatem Abdel Rahman

Left to right: Prof. Nada Naaman from Lebanon, Prof. Maguid Amin, Prof.Hatem Abdel-Rahman

Left to right: Prof. Tarek Abbas Hassan, Prof. Maguid Amin, Prof. Hatem Abdel-Rahman, Prof. Mouchira Salah-El-Din, Prof. Hesham Katamesh, Prof. NourHabib during the opening ceremony

Left to right: Dr. Mourad Abdul Salam, Prof. Maguid Amin, Prof. HatemAbdel-Rahman, Prof. Mouchira Salah-El-Din exchanging trophies

“It is indeed one of the major benefits ofscientific exchange to bring differentpeople from all over the world together”


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Left to right: Prof. Ahmed Farid Shehab and Prof. Hesham Katamesh Left to right: Prof. Mohamad Nassar V.P. of Tanta University , Prof. MaguidAmin and Prof. Hatem Abdel-Rahman

Left to right: Prof. Ahmed Farid Shehab, Prof. Nour Habib Dean of CairoUniversity, Dental school, Prof. Maguid Amin and Prof. Hatem Abdel-Rahman

Left to right: Prof. Tarek Sharkawi, Prof. Maguid Amin, Prof. Hatem Abdel-Rahman, Prof. Tarek Abbas Hassan

Prof. Mouchira Salah-El-Din displaying the new GALAXY Dental Lasermachine

Dr. Eduardo Mahn lecturing on stress management for compositerestorations

LECTURES

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Dr. Najla Chebib from Lebanon after her talk on new ceramic material Dr. Abd El-Salam El-Askary from Alexandria exposing the handling ofcomplications in implantology

Dr. De Souza from California lecturing on prosthetics over implants Picture from the audience

Dr. Tony Dib receiving a trophy of appreciation from the Egyptian Dental Association Board during the closing ceremony

CLOSING CEREMONY

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Dr. Mohammed Ban Hafeed Chairman of Yemen’s Dentist Syndicate withDr. Mahmoud El Mais from Lebanon

Dr. Tony Dib, Dr. Mohammed Saadeh and Dr. Mohammed Ban Hafeedon an excursion near the Sphinx

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TEBODONT®:Successful against oral microorganisms

Dr. König, how did you discover Tea Tree Oil?We received samples of TEBODONT® Gel two years ago.Clinically, I noticed quickly that it is less irritating thanChlorhexidin. In addition, and very important for us: it does notproduce any discolorations.This plays an important role to our patients who notice evensmallest discolorations on their bleached teeth. Another advan-tage of Tea Tree Oil: it acts successfully against Candida albicans.Nowadays, I don't use Chlorhexidin anymore.

When do you use Tea Tree Oil products?Always after surgical interventions. And always after implanta-tions: the parts to be screwed on the implants are soaked in TeaTree Oil before. We also use it in case of troubles after the treat-ment - in Candidiasis. Our Dental Hygienist gives it in cases ofperiodontitis. And, since a few patients told us that they couldsignificantly reduce their aphtae problem with the Tea Trea Oiltoothpaste, we also recommend it for this indication.Tea Tree Oil has become an universal remedy in our Clinic. TheGel is primarily used during the treatment and postsurgical, theother products are given to the patients for home care.

How do your patients react on Tea Tree Oil?There are patients who do not like the taste of Tea Tree Oil.Others, like myself, appreciate the refreshing taste. The positivefeedback we get from the patients:In contrast to Chlorhexidin, Tea Tree Oil does neither discolourthe teeth, nor change the sense of taste.

Tea Tree Oil is an universal remedy in our Clinic.Dr. med. dent. Arno König, Head of the Medical Dental ClinicBethanien, Zurich/Switzerland

“”

The essential oil of the australian tea tree (Melaleuca Alternifolia) is moreand more used in oral hygiene with a remarkable success. In the MedicalDental Clinic of Bethanien (Professor Sailer) in Zurich / Switzerland it hasbecome an universal remedy within a short lapse of time.“I don't use Chlorhexidin anymore” said the Head of the Clinic, Dr. ArnoKönig, who uses above all the Gel and the Mouthrinse out of the differentTea Tree Oil products (TEBODONT®).

Tea Tree Oil is an universalremedy in our Clinic

ADVERTORIAL


Topex® Fluoride Foam Easy, 60-second application. Dense

enough to provide excellent coverage,

yet stays in the tray under bite pressure

for a more pleasant patient experience.

Five delicious flavors!

Topex® Dual Arch Fluoride TraysIts natural arch and more defined

occlusal anatomy helps force fluoride

onto all biting and interproximal

tooth surfaces. Locking handles

allow for easy placement and

removal. Available in four sizes.

Topex® APF Fluoride Gel Thixotropic formulation

remains in the tray, reduc-

ing fluoride ingestion.

Fast, 60-second

application. Available

in five great

Topex flavors.

Topex® TopicalAnesthetic

Quick onset delivers

maximum strength

20% benzocaine for

fast, temporary relief

of pain. Reduces

salivation, keeping

gel active longer.

Seven great flavors!

If you like DuraShield®, you’ll love these Sultan products…

Why take a risk and waste time? DuraShield® is an incredibly effective,

fluoride treatment that’s effortless to apply. Its light amber color lets you know the tooth

surface is completely covered, yet is almost undetectable to your patient. Each .40 ml unit

dose pack can be mixed prior to application, guaranteeing a consistent fluoride level.

And with the handy UltraBrush™ 2.0 bristle brush, DuraShield is a total application system…

just pop it open, and you’re ready to go.

But most important, DuraShield works. As a powerful desensitizing agent,

DuraShield relieves hypersensitivity where dentin or cementum are exposed.

Its 5% sodium fluoride formula sets on contact with saliva and releases

fluoride for up to eight hours. That means enhanced fluoride uptake, with

minimal food or drink restrictions for your

patients. You can be confident your

patients are protected. And the Bubble

Fun® Flavor is great for patients of all ages.

Easy… fast… effective. When it

comes to doing the job right on fluoride

treatments, you can’t miss with DuraShield.

It’s easy to do if you use a white fluoride varnish. DuraShield® is easy to see and apply—every time.

Youmisseda spot...

Pre-applicationmixing ensuresfluoride content.

Light amber color meansfull coverage withoutcompromise of esthetics.

UNIT DOSE MIXING LIGHT AMBER COLOR

Ever Wish For AScaler That TrulyStayed SharperLonger?

Manufacturer: Hu-Friedy Mfg. Co., Inc. 3232 N. Rockwell Street Chicago, IL 60618 I USAEuropean Headquarters & Customer Care Department: Hu-Friedy Mfg. B.V. P.O. Box 29025 I NL-3001 GA Rotterdam Tel. +800 HUFRIEDY (+800 48 37 43 39) Fax +800 48 37 43 40 E-Mail: [email protected] I www.hu-friedy.euHu-Friedy Middle East: Mobile : 00 962 79 50 45 700 E-mail: [email protected]

Sharpen Less Often Revolutionary new stainless steel alloy issuper-durable

Stays sharper longer That means less time sharpening and lesshand fatigue.

Proprietary ProcessProprietary heat treat and cryogenicprocessing ensure that the superior edgeretention and wear characteristics ofEverEdge Technology® will last the entirelife of the instrument. It’s not a super -ficial coating – EverEdge Technology®

scalers can be sharpened again and againfor your best instrument value.

Diamond KnurlUnique diamond knurl pattern with largediameter handle for a confident grasp.Optimal weight for reduced handfatigue.

Comfort Zone Cone with Signature Series gripThe cushioned grip provides a smoothtransition and increased comfort.Distinctive Ocean Blue grip for easyidentification.

Finely-Honed Finish EverEdge Technology® Scalers feature afinely-honed finish to the instrumentblade, for super sharp edges and efficientscaling.

1/2DIN

1/4DIN

1/2 DIN cassette for 10 instrumentsDimensions: 152 x 184 x 32 mm

1/4 DIN cassette for 5 instrumentsDimensions: 72 x 184 x 32 mm

IM14DIN58

DIN

DIN cassette for 13 instruments + spaceDimensions: 290 x 184 x 32 mm

IMDIN138

IM12DIN105

PRODUCT NEWS

72

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S


So Simple. So Smart.

The Hu-Friedy Sidekick Sharpener makes routine maintenance sharpening

of scalers and curettes fast and easy. This straightforward device guides

you and your scaler to sharp, consistent results time after time.

Reliable Results.

The Hu-Friedy Sidekick sharpener is the only power device with instru-

ment Guide Channels and a Vertical Backstop to help control blade angu-

lation. These "template-like" features allow virtually effortless positioning

of your scalers/curettes and provide consistent sharpening results. Correct

routine sharpening will help extend the life of your instruments.

The Sidekick is Always Within Reach.

It’s cordless! The small, compact, cordless Sidekick can be placed any-

where and requires minimal counter space – perfect for anywhere in your

dental office.

See how easy and fun sharpening can be! Sharpen at your convenience

with the Hu-Friedy Sidekick, The Smart Sharpener.

• Kit Includes - Sidekick Unit, User Manual & CD-ROM, Ceramic

Sharpening Stone, Plastic Test Stick, Magnifying Lens and 2 AA Batteries.

www.hu-friedy.com

Sidekick® SharpenerWelcome to the Edge of Sharpening Technology

Swiss Medical Technology (smt) is based in Switzerland and active in

design, development, manufacturing and international distribution of

innovative ergonomic dental equipment. With its products for diagnos-

tics and therapy, smt offers a maximum of quality and efficiency in den-

tal treatments.

One year ago, smt successfully presented the first optical 3D-system –

the Dentaloscope 3D – and set a new benchmark in microdentistry. At

present, smt continues its orientation on innovative methods of treatment

by launching an accordant 2D-system called Dentaloscope 2D. The dentist

also sits in an ergonomic, upright position and works indirect via monitor.

Thus back or neck problems, due to a bench over working posture, are

a thing of the past – a quantum leap in history of dentistry.

The Dentaloscope 2D with its unique features permits a new kindof treatment:

Feel the difference

Is it not time to go home more relaxed? With the Dentaloscope 2D a

hard typical workday with tired eyes, pain in the cervical, shoulder or

back area is finally a thing of the past.

Experience new dimensions

With the aid of the Dentaloscope 2D diagnosis and treatment is possi-

ble in an impressive way: A full panoramic view with 2.5x magnification

up to the smallest view with a maximum magnification of 55x can be

displayed. Besides, the depth of focus is unrivaled with its 150 mm. It is

no longer necessary to reposition the camera, because it is possible to

focus simply and fast between free working distances of 160 – 420 mm.

Do not be in the dark

The shadow-free light source is created by the integrated high-perform-

ance LED-technology which illuminates the treatment area similar to

daylight with 47'000 lux.

Pictures speak louder than words

Diagnostic findings and the success of a treatment can be visualized to

the patients via the impressive flat screen. With the Quattro-shot fea-

ture, four single pictures can be displayed in one sequence. The han-

dling of the image storage results easy and effortless by operating the

foot control panel.

www.s-m-t.ch

“You can only treat what youcan see“ – creating visions

PRODUCT NEWS

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S

Presenting MICRO-MEGA®'s new Revo-S™ Refill Box, set of packs of thenew Nickel-Titanium sequence Revo-S™, at an attractive price.

The Revo-S™ unique and innovative sequence offers an optimal root canalcleaning with only 3 instruments!

This limited edition "gold" box includes:- 2 packs of 6 instruments SC1- 2 packs of 6 instruments SC2- 2 packs of 6 instruments SU- 1 pack of 3 instruments assorted AS30-AS35-AS40

This Revo-S™ Refill Box is available in InGeT® and Classics versions.e-mail: www.micro_mega.com

MICRO-MEGA®'s new Revo-S™ Refill Box

74


VITA VACUMAT ceramic furnacesWith the innovative concept of the "New Generation" for VITA

VACUMAT ceramic furnaces, VITA Zahnfabrik presented a world novelty

at the IDS. Thanks to its modular construction, the unique system makes

perfect individual solutions possible, and is therefore extremely econom-

ically efficient. With the introduction of additional modules, it now offers

even more flexibility.

Premium firing and pressing technology!The VITA VACUMAT 6000 M is a microprocessor-controlled, fully auto-

matic premium firing unit for all types of veneering ceramic and crystalli-

sation firings. The new VITA VACUMAT 6000 MP is used as a combined

unit not only as a firing, but also as a pressing unit, and can therefore be

used for all dental ceramics as well as with various muffle systems avail-

able on the market.

The innovative firing and pressing technique as well as numerous moni-

toring and service functions result in consistent firing results of convinc-

ing quality, while simultaneously saving time for the user. These features

include, for example, the automatic temperature adjustment at the start

of every program, the automatic cleaning function, the avoidance of

condensation formation in the insulating material as well as power fail-

ure protection and controlled fast cooling. The current operating status

is immediately apparent at all times thanks to an LED light bar visible from

a distance, as well as acoustic signals offering a choice of different sounds.

For further information, see under www.vita-zahnfabrik.com or call

the VITA Hotline on +49 (0) 7761-562 222

BEAUTY – COMPOSE IT!

Highly aesthetic restorative

Two simple steps

Layers like in nature

Brilliant results

VOCO GmbH · P.O. Box 767 · 27457 Cuxhaven · Germany · Tel. +49 (0) 4721 719-0 · Fax +49 (0) 4721 719-140 · www.voco.com

NOW AVAILABLE INGINGIVA SHADESPlease visit us at AEEDC

Booth: 446

PRODUCT NEWS

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VOCO developed x-tra fil, a hybrid composite, especially for quick and

effective use in the posterior area. The light-curing restorative permits

tooth-shaded, load-bearing, cavity class I and II restorations. x-tra fil is

thus a high quality, durable and cost-effective alternative to amalgam

restorations. Due to its time-saving processing, x-tra fil is particularly

well-suited for patients with limited compliance. In addition to posteri-

or restorations, x-tra fil is also well-suited for economical core build-up.

This composite is available in a universal shade and both in handy

syringes and convenient Caps for direct application. x-tra fil is now

available in the especially economical, bulk package (10 x 5 gram syringe).

Excellent material properties and optimal handlingOutstanding physical properties and unproblematic handling is what

makes x-tra fil, with its minimum time requirement and equally high

safety, an efficient standard treatment in the posterior area. x-tra fil's

excellent material properties were achieved with a combination of a

new multi-hybrid filler technology and an innovative initiator system for

photo-polymerisation. This is how increments of up to 4 mm in thick-

ness can be safely cured with only 10 seconds of exposure (light output

min. 800 mW/cm2) with only a minimal amount of polymerisation

shrinkage. The reduced shrinkage tension in x-tra fil delivers the foun-

dation for a durable, marginally tight restoration. x-tra fil meets the

special requirements for high wear, load-bearing restorations with its

dentine-like compressive strength, thermal expansion behaviour and

high abrasion resistance. Due to its very high radiopacity, x-tra fil pro-

vides an excellent radiological contrast to the tooth substance and thus

ideal prerequisites for subsequent diagnoses. The high translucency of

the material produces a chameleon effect and thus an aesthetic shade

match to the surrounding tooth substance.

www.voco.com

E-mail: [email protected]

Efficient posterior treatmentwith x-tra fil

inEos Blue: Precision and SpeedNewly designed CAD/CAM scanner enables fast, easy and controlled

scans. Bluecam technology sets new standards of precision.

Control

Thanks to the new user-friendly scan grid and new model holder, oper-

ating the inEos Blue is child’s play. The models can be moved in all direc-

tions and angles. The rotation mouse enables 360° scans to be per-

formed at any inclination angle up to 105° – ideal for capturing heavily

undercut stump preparations and abutments. In addition, the buccal

registration of the upper and lower jaws enables the precise definition of

the occlusal contacts.

Precision

The scanner camera is equipped with the innovative Bluecam technolo-

gy. The very small triangulation angle of 3° means that deep cavities can

be captured in their entirety, i.e. without undercuts.

Speed

The inEos Blue can capture a single stump in just a few seconds.

Scanning a multi-unit bridge takes less than one minute. Thanks to the

short scanning times and the automatic capture function, the inEos Blue

is currently the fastest dental CAD/CAM scanner on the market.

STL ready

The inEos Blue can save and export scanning data in STL format thereby

allowing the data to be processed using third-party software.

www.sirona.com

inEos Blue: The new scan grid and thenew model holder enable simple andcontrolled scanning.

Bluecam technology:short wavelength bluelight delivers an exten-sive depth of field, aswell as the enhancedreproduction of detailsat the preparation margins

When it comes to performance – the more the better. Now is

your chance to benefit from maximum performance and

efficiency with the VITA VACUMAT New Generation. Operate

up to four premium furnaces of the VACUMAT 6000 M series

and/or the combination pressing furnaces of the VACUMAT

6000 MP series with a single vPad control panel and set new

standards for optimised workflow in your laboratory. Thanks to

its modular structure, the firing system can be customised

to meet your requirements. Plus, you can add further firing

units, operating panels and accessories at any time. You will

hardly find a more efficient way to meet future requirements.

www.myvacumat.com

3389

_2E

Operate up to four firing units with a single operating panel.

VITA VACUMAT® New GenerationProductivity to the power of four!

PRODUCT NEWS

The new Chiropro-L implantology system, from Bien-Air, takes performance

and ergonomics a stage further with the only control unit on the market

incorporating the pre-programmed clinical sequences of the seven

biggest implant brands. The practitioner just chooses the appropriate

sequence and that's it!

Its micromotor, the most powerful in the world, can perform the whole

range of surgical operations very simply. It is provided with LED lighting,

adjustable to any speed from 100 to 40,000 rpm.

Chiropro-L comes complete with the new 20:1 L contra-angle hand-

piece with light, the very first to have internal irrigation, allowing easier

practitioner movements. Other features are its very light weight and its

small-sized head offering an improved field of vision.

http://www.bienair.com/

The new Chiropro-L implantologysystem, from Bien-Air

New! Cavex ImpreSafeIn more and more countries it is legally mandated to disinfect alginate or

silicone impressions before sending them to a dental-technical laborato-

ry. Although Cavex has kept abreast of the latest developments, there

were no disinfectants on the market until recently that we, as an author-

ity in the field of alginate and silicone impressions, could endorse. All the

regular disinfectants damage the surface of the impression due to a

lengthy contact time or an aggressive composition. Now, Cavex

ImpreSafe has changed all this. Cavex ImpreSafe is a non-toxic disinfec-

tant without aldehyde that takes only three minutes to be effective. Due

to this extremely short contact time the surface of the impression

remains 100% intact and negative impact on the end result is avoided.

Cavex ImpreSafe is a complete disinfectant system and comes with 1 litre

of disinfectant concentrate, a disinfectant container, timer and protocol.

For more information, visit www.cavex.nl.

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Your impression is our concern!

Cavex GreenClean

100% bio degradable alginate and gypsum dissolver.

Cavex Impressional

Cavex ColorChange

Superior, highly tearresistant alginates.

25micron detail reproduction

Dim

ensional Sta

bility

Dim

ensional Stability5days

www.cavex.nl - [email protected] - tel: +31 23 530 77 00 - fax: +31 23 535 64 82

NEW! Cavex ImpreSafe

lginate and silicone disinfectant.100% safe for impression surfaces.Disinfection in only 3 minutes.

Sequal

sa

NEW! Cavex SiliconA

LED Coupling andUnrivalled Cutting Performance

LED couplings realize clearer view with your optic air turbines.

And unrivalled cutting performance, slim ergonomically designed body

and excellent visibility. The NSK S-Max M Series has been

designed without compromise. Experience it for yourself.

M600KL

KaVo® Coupling

M600L

NSK Coupling

Air Turbines

KaVo® and MULTIflex® LUX

are registered trademarks

of Kaltenbach &

Voigt GmbH & Co.

NSK Power

SuperbClarity & Durability

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