Smnr - 4... Wound Healing

7/28/2019 Smnr - 4... Wound Healing

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WOUND HEALING



Contents :

Wound healing

Regeneration & repair

Healing by primary intention & secondaryintention

Healing in fractures

Healing of extraction socket & its complications

Factors influencing wound healing

Methods of control of hemorrhage

Causes

Prevention

Management

Prosthetic considerations





Therefore, WOUND HEALING, is the body's

ability to repair the injured tissues, by:

1) replacement of the injured or dead cells bythe new cells of the same kind, i.e.Regeneration.

2) replacement by the connective tissue, i.e.Fibrosis.





depending upon their capacity to divide cells ofthe body are divided into 3 main groups:

1) LABILE CELLS (continuously dividing cells)

2) STABLE CELLS (quiescent cells)

3) PERMANENT CELLS (non-dividing cells)



REGENERATION:

G0, G1, S, G2

PHASE





Granulation tissue formation

1. phase of inflammation

2. phase of clearance

3. phase of ingrowth of granulation tissue-- angiogenesis

-- fibrosis



Contraction of wounds:

(a) dehydration

(b) contraction of the collagen

(c) discovery of the myofibroblasts





** WHY NO SCAR FORMATION IN THE ORALCAVITY?-- The oral cavity has many structurally different

tissues that likely heal in different ways.Periodontists and oral surgeons are well awarethat incisions in the buccal mucosa result inscars, whereas harvesting gingival grafts from

the palate produces no visible sign of scarring.In addition, incisions in the gingiva itself healwithout scars.



-- Various reasons have been suggested forminimal scarring in the oral cavity, includingdistinct fibroblast phenotype, the presence ofbacteria that stimulate wound healing and the

moist environment and growth factors presentin saliva.This effect of saliva is attributed mainlyto its relatively high concentration of epidermalgrowth factor (EGF), and topical use of artificial

saliva has been suggested as a treatment forskin burn wounds.



Wound Healing:

Inflammation

Epithelialization

GranulationContraction

Remodeling



Healing by Primary Intention:

Healing of clean, uninfected, surgicalincisions

Focal disruptions of basement memb.

Continuity

Within 24 hrs.

Netrophils…

Inc. mitotic activity of basal cells

Cells meet in midline below scab



Day 3 :

Neutrophils replaced by macrophages

Invasion of granulation tissue

Vertically oriented collagen fibers

Thick epithelial covering

Day 5 :Neovascularisation – peak

Abundant collagen fibers

Differentiation - keratinisation



During 2nd week:

Continued collagen accumulation &

fibroblast proliferation

Vascularity, edema, leukocyte infiltration

decrease

Collagen inc.

By end of 1st month:

Scar devoid of inflammatory cells

Dermal appendages lost permanently

Tensile strength inc. …



Healing by Secondary

Intention: More extensive wounds – infarcts, inflamm. Ulcers,

abcess or large wounds

Healing from below upwards & margins inwards

Slow & leads to scar formation



Initial hemorrhage:

Wound filled with blood & fibrin clot

Inflammatory phase:

Acute inflamm cells, then macrophages

Epithelial changes:

Proliferation from both margins

Surface not covered till granulation tissue startsfilling wound space

Scab cast off



Granulation tissue:

Main bulk

Fibroblasts & neovascularisation

Deep red, granular & fragile but – pale

Wound contraction:Not seen in primary healing

Due to myofibroblasts

1/3 – ¼ the original size





Wound Strength

Sutured wounds – 70% of unwounded skin

1 week- 10%

4 week- inc3 month- 70-80%

No further increase



Complications…

Infection

Pigmentation

Implantation

Deficient scarHypertropied scar & Keloid

Excessive contraction

NeoplasiaIncisional hernia



Factors influencing healing

A) LOCAL FACTORS

1) infections

2) poor blood supply

3) foreign bodies

4) movement5) exposure to the ionising radiations

6) UV-Light



B) SYSTEMIC FACTORS

1) Age

2) Nutrition

3) systemic infection

4) administration of the glucocorticoids

5) uncontrolled diabetics

6) haematological disorders



HEALING IN THE SPECIALISED TISSUES:

FRACTURE HEALING

Healing of the fracture by callus formation

However the basic events in the healing of any type of

fractures is similar and resemble healing of the skin

wound to some extent.



*** PRIMARY UNION OF FRACTURES:

-- it occurs in few special conditions when the ends of

the fracture are approximated and is done by the

application of the compression clamps.

-- in these cases the bony union takes place with

formation of the medullary callus without theperiosteal callus formation.



*** SECONDARY UNION OF THE

FRACTURES:

-- its a more common process of fracture healing.-- though its a continuous process its described under

following headings:

1) PROCALLUS FORMATION:

-- Haematoma-- Local inflammatory response-- ingrowth of the granulation tissue-- Callus composed of the woven bone and thecartilage



2) OSSEOUS CALLUS FORMATION: -- the procallus acts as a scafolding over whichosseous callus composed of lamellar bone isformed.

-- The woven bone is cleared away by the

incoming osteoclasts and the calcified cartilagedisintegrates.

-- in their place newly formed blood vessels and

the osteoblasts invade, laying down the osteoidwhich is calcified and the lamellar bone isformed by developing the Haversian systemaround the blood vessels.

3) REMODELLING



3) REMODELLING:

-- during the formation of the lamellar bone,

both the osteoblastic and the osteoclasticactivity takes place, thus remodelling the unitedbone ends, which are sometimesindistinguishable from the normal bone.

-- External callus is cleared away.

-- Intermediate callus gives place to the

compact bone.

-- Internal callus develops the bone marrow

cavity in it.



Healing of extractionsocket



Healing Of Extraction SocketImmediate Reaction :

Blood fills the socket & coagulates

Torn blood vessels – sealed off

Vasodilation & engorgement

Leukocytes around the clot

First Week Wound :

Fibroblast proliferationClot acts as scaffold

Mild mitotic activity

Clot organization, no osteoid formation



Second Week Wound :Clot organization progresses

Remnants of PDL – degeneration

Epithelial ProliferationSocket margins – osteoclastic activity

Third Week Wound :

Clot totally organizedOsteoid bone formation

Rounded crest

Complete epithelisation of surface

Fourth Week Wound :Continuous remodeling & deposition

Crest below adjacent tooth

Radiographic evidence – 6-8 weeks



Complication of sockethealing

Dry Socket/Alveolitis SiccaDolorosa/Alveolitis Osteitis/AcuteAlveolar Osteomyelitis/Alveolagia

Most common

disintegration of clot

95% in lower premolars & molars

Within 2nd or the 3rd day

Extremely painful

Palliative medicine & dressings

Reviewing the patient

Pack socket with obtundant



-- First time the term "DRY SOCKET" was usedby Crawford in 1896.

-- its a post-operativecomplication that occursafter a dental extraction.

-- its defined as "postoperative pain in andaround the dental alveolus, which increases inseverity during the 1st and the 3rd day, after adental extraction, accompanied by a partial ortotal disintegration of the intra-alveolar clot,accompanied invariably with a foul smell.



The condition derives its name from the fact that

after the clot is lost the socket has dryappearance because of exposed bone.



** It may occur due to frequent and forceful

spitting after extraction, smoking or excessivetraumatic extraction. Disintegration of clot maybe due to infection of the wound. Bacterialenzymes hyaluronidase and fibrinolysin causes lysis of clot.

**The bone of the socket becomes necrosed,

grayish bone is seen from the socket and badodor is present at the socket and pus is minimalor not at all.



** For the treatment of dry socket, intra-alveolarpastes consisting of the zinc oxide eugenol

paste, anaesthetic and an antibiotic(metronidazole) can be placed. A strip of pastesoaked surgical gauze should be placed gentlyinto the socket.

** Antibiotics and analgesics are not effective ifused alone because of poor vascularity of the

necrosed bone.



Fibrous healing

+Rare

Loss of labial & lingual plates

Dense fibrous mass on exploration

This loss of cortical periosteum causes

improper healing and scar tissues are found at

the site. These fibrous connective tissue may

ossify a little or not at all.

For the Treatment, excision of the lesion forthe purpose of establishing a diagnosis will

sometimes result in normal healing and

subsequent bony repair of the fibrous defect.



Methods to control Hemorrhage:

Causes: some amount of bleeding is normal

after an extraction. This usually stops after theapplication of the pressure in a couple ofminutes. Excessive bleeding will be seen inhypertensives and where a blood vessel has

been severed.



Prevention: excessive bleeding can be prevented

by the atraumatic extraction. In thehypertensives make sure that the blood pressureis under control before the extraction.



-- patients on the anticoagulants should beinvestigated properly and a physician's opinionshould be taken.

-- incision should be planned properly to avoidany damage to the major vessels.





2) Visualise: -- if the bleeding does not stop then a properly

cleaning the the area and then examination isdone under proper light, to visualise the regionand examine.

-- look for the spot of the bleeding, if thebleeding is from the soft tissue area, pressurewill stop the bleeding.

-- if its from the bone then locate the exact pointand then open up a gauze piece to make a thinstrip and pack tightly into the socket to preventthe bleeding.





4) Sutures: -- bleeding from the soft tissues may be

controlled by placing the sutures as this helpsto compress the mucosa against the bone andreduce the bleeding.



5) Cautery: --bleeding from the bone may be controlled by

the cauterisation. The exact bleeding point isfirst located.-- the area is first dried as much as possible

and then a hot ball burnisher may be used to

cauterize.-- electrocautery may also be used for the

same.

6) Li ti



6) Ligation:

-- if a major artery is severed, then it may be

needed to be ligated.

7) Gel foam:

-- this is a gelatin based sponge, which acts by

disrupting the platelets and establishing aframework with fibrin strands to create a clot. Itgets absorbed within 4-6 weeks.

8) Oxidised Cellulose:



8) Oxidised Cellulose: -- it releases the cellulosic acid, which has a

marked affinity for the hamoglobin, leading to

the formation of the artificial clot.

-- these substances may be placed in the socketto enhance the clot formation and thus control

the bleeding.

9) Fibrin Glue:

--this consists of a fibrinogen and thrombin,which thus when applied leads to decrease thebleeding by stabalising the clot formed.



10) Bone Wax:

-- this is the mechanical agentto block the bleeding vessel.

--bleeding from the bone may be occluded byplacing small piece of bone wax firmly on thespot of bleeding.

--The patient should be made to wait for sometime after extraction in the clinic to confirm theabsence of the bleeding.



** PROSTHETIC CONSIDERATIONS:

** IMPRESSIONS MAKING :

-- Any impression making, should be carried out

only when the extraction sockets and the oralmucosa are completely healed.

-- If any unhealed sockets are present then the

patient is asked to wait till the healing iscomplete.



-- Once the gum tissues and bones of the jaw

have completely healed--which may take atleast six to eight weeks, according to theAmerican Dental Association--the patient can befitted for a set of permanent dentures.

-- impressions of the unhealed sockets will leadto the pain and discomfort during the procedureand the dentures prepared will not fit as

afterwards the healing would have taken placealong with the bone formation in the socket.



** IMMEDIATE DENTURES:

-- its a complete denture or a removable partialdenture, fabricated for the placementimmediately after the removal of the naturalteeth.

-- These immediate dentures, help to protect thegums, as well as numbing the pain.

-- Troublesome hemorrhage is rare because theimmediate dentures act as a bandagethemselves.



-- less post-operative pain is likely to be

encountered because the extraction sites arewell protected by the immediate dentures.

-- as tissue conditioning materials are used forthe correction and the refinement of thedentures fitting surface, so care should betaken so that the material does not get into the

extraction socket. And for this the extractionsocket is covered by the "BURLEW FOIL".



-- also, any projections of the tissueconditioning material inside the denture should

be trimmed because if this is overlooked, normalsocket healing will be then compromised andthe ridge will heal with small concavitiesoverlying the extraction sockets leading to the

formation of the "KNUCKLE SHAPED RIDGES".

-- dentures should not be removed during thefirst 24 hours as inflammation and swelling can

occur and if the dentures are removed then itsdifficult to reinsert them for 3-4 days, due toswelling.



** IMMEDIATE IMPLANT PLACEMENT:

-- Dental implants can be placed in fresh sockets

immediately after tooth extraction. These are called

"immediate" implants.

-- "Immediate-delayed'" implants are those implants

inserted after one or more weeks, up to a month or

more, to allow for soft tissue healing.

-- "Delayed" implants are those placed thereafter in

partially or completely healed bone.



-- The advantage of immediate placed implantsis the shortened treatment time. Bone height

will be maintained thus improving implant bonesupport and aesthetic results.

-- The extraction socket can have an implant

placed immediately after a Chronically infectedtooth is removed, but needs to have thereplacing implant anchored into bone and thesite grafted at the same time with a PTFE

membrane that excludes soft tissue, allowingthe bone grafted socket site to heal normallywith the newly placed implant.



** WOUND HEALING IN DIABETICS: -- delayed wound healing occurs in the diabetics

due to the decreased polymorphonuclearchemotaxis.

-- they are more prone to the infections as the

gingival fluid too contains more of the glucose levels which favors the growth of the microflora.

-- Delayed vascularization, reduction in blood

flow, decline in innate immunity, decreases ingrowth factor production, and psychologicalstresses may be involved in the protractedwound healing of the oral mucosa in diabetics



-- Poor circulation: If you have had diabetes for a

long while, you probably have fatty deposits inyour arteries that slow down blood flow causingpoor circulation. Poor circulation can limit theamount of oxygen and healing nutrients that

reach a wound.

-- Endothelial progenitor cells (EPCs), whichderive from bone marrow, normally travel to

sites of injury and are essential for the formationof blood vessels and wound healing.



-- the numbers of these vital EPCs are decreasedin the circulation and at wound sites in diabetes.

-- The high oxygen levels increased theactivation of the bone marrow enzyme eNOS,which stimulated nitric oxide production, helpingto produce greater numbers of EPCs.

-- impaired eNOS activation in diabetes are

responsible for the defect in diabetic woundhealing.



CONCLUSION:

Wound healing is a complex and dynamic process of

restoring cellular structures and tissue layers. Its of

importance to a prosthodontist in a way as it

determines the time during which the prosthesis canbe given to the patient. There are various factors

which effect the wound healing and we should know

all the factors which effect the period of wound

healing.



REFERENCES:

*Robbin’s & Cotron Pathological basis of diseases -7th

edn.

*Essential pathology for dental students – Harsh

mohan,3rd edn.

*Textbook of oral & maxillofacial surgery – Balaji.*Human embryology - Inderbir Singh 4th edn

*Prosthodontic Treatment for Edentulous Patients –

*Bouchers 12th edn

*Essentials of complete denture Prosthodontics -Winkler, 2nd edn

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Smnr - 4... Wound Healing