Slide 1

JONAS ADHIKARI..

What is wound???A wound is a break in the integrity of skin and tissues often;which may be associated with disruption of structure and function.

CLASSIFICATIONBASED ON: 1.Origin of wound2.Contamination of wound3.Depth of wound

BASED ON ORIGIN.1.MECHANICAL. 2.CHEMICAL (a)Abraded wound Acid and base(b)Punctured wound 3.RADIATION(c)Incised wound(d)Cut wound 4.THERMAL(e)Crushed wound Burning and freezing(f)Torn wound (g)Bite wound 5.Special(h)Shot wound Toxins and venoms

BASED ON CONTAMINATION1.Clean wound

2.Clean and contaminated wound

3.Contaminated wound

BASED ON DEPTH1.Superficial wound :: Only epidermis

2.Partial thickness wound:::Epidermis +dermis

3.Full thickness wound:::: Epidermis+ dermis+ subcutaneous fat

4.Deep wound:::::::Epidermis +dermis + subcutaneous fat + exposed muscles ,bone, connective tissue and organs..etc

HEALINGDEFINITION: Healing is the bodys response to injury in an attempt to restore normal structure and function

Factors responsible for angiogenesis;; 1.Vascular endothelial growth factor 2.Platelet derived growth factor 3.Transforming growth factor 4.Fibroblast growth factor.

Migration of fibroblasts..Recruitment and stimulation of fibroblasts is driven by growth factors like PDGF,FGF-2 and TGF-beta..

.Macrophages elaborate host of mediators that induce fibroblast proliferation and ECM deposition.. ROLE OF TGF-beta .is a potent fibrogenic agentstimulate production of collagen,fibronectin,proteoglycans. .inhibit collafen degradation by decreasing proteinase activity and increasing activity of tissue inhibitors of roteinases(TIMPs)

GRANULATION TISSUE..Phases in the formation of granulation tissue. .PHASE OF INFLAMMATION. Injury blood clot Acute inflammatory response with exudation of plasma, neutrophils,and some monocytes within 24 hrs.

.PHASE OF CLEARANCE Proteolytic enzymes liberated from neutrophis, autolytic enzymes from dead tissue and phagocytic activity of macrophages clear off the necrotic tissue,debris and red blood cells..

Composed of;:spindle shaped fibroblasts, dense collagen, fragments of elastic tissue and other ECM components..

Reepithelialization.Reepithelialization which is wound recovery with new epithelium and consists both migration and proliferation of keratinocytes from the lesion periphery also occurs during this phase.

Remodelling phase

.The outcome of repair process is balance between ECM synthesis and degradation..Degradation is accomplished by family of matrix metalloproteinases(MMPs).MMPs include interstitial collagenases gelatinases stromelysins

Contraction of wound.The wound starts contracting after 2-3 days and the process is completed by 14th day. During this period wound is reduced by approx.80% of its original size.

.Factors responsible for wound contraction:

1.Dehydration due to removal of fluid s by drying. 2.Contraction of collagen. 3.Discovery of myyofibroblasts.

SUMMARY OF HEALING..

Growth factors and cytokines affecting various steps in wound healing.

!Epithelial proliferation : EGF, TGF-alpha, KGF, HGF! Monocyte Chemotaxis : PDGF, FGF, TGF-beta!Fibroblast migration: PDGF, FGF, TGF-beta!Fibroblast proliferation : PDGF, EGF, FGF, TNF!Angiogenesis: VEGF,FGF!Collagen synthesis: TGF-alpha, PDGF!Collagenase secretion: PDGF, FGF, EGF, TNF ;TGF-beta inhibits

TYPES OF WOUND HEALING

.HEALING BY FIRST INTENTION also called as PRIMARY UNION

.HEALING BY SECOND INTENTION also called as SECONDARY HEALING..

Factors affecting wound healing..(A)LOCAL FACTORS :.Infection.Presence of necrotic tissue and foreign body..Poor blood supply..Venous or lymph stasis..Tissue tension.Hematoma.Recurrent trauma.Immobilization.Site of wound.Mechanism and type of wound..Tissue hypoxia locally reduces macrophage and fibroblast activity..

Contd.(B)GENERAL FACTORS ;;

.Age,obesity,smoking.Vitamin deficiency.(Vit.C and Vit.A)Anaemia.Malignancy.Uremia.Diabetes,metabolic diseases.HIV and immunosupressive diseases.Steroids and cytotoxic drugs.

FIVE PHASES:

1.Immediate reaction

2.First week wound

3.Second week wound

4.Third week wound.

5.Fourth week wound

1.IMMEDIATE REACTION

Removal of tooth

Blood fills the socket and coagulates..within 24-48 hours..Vasodilatation and engorgement of blood vessels ,mobilization of leukocytes immediately around the clot.

Surface of the blood clot is covered by a thick layer of fibrin

2.FIRST WEEK WOUND

.Fibroblastic proliferation around the periphery

Clot acts as scaffold

gradually replaced by granulation tissue. epithelium at periphery proliferates.

clot undergoes organization..:ingrowth of fibroblasts and capillaries.

2.SECOND WEEK WOUND

Fibroblasts grow into clot(clot becomes more organized)

extensive epithelial proliferation over the surface

margins of alveolar socket-osteoclastic resorption,PDL remnants degenerate

Bone fragments(necrotic)resorption or sequestration.

3.THIRD WEEK WOUND..

Original clot organized(mature granulation tissue)

young trabeculae of osteoid-entire wound periphery

osteoid produced by osteoblasts derived from pleuripotent cells of PDL.

crest of alveolar bone-round off by osteoclastic resorption

Surface of wound completely epithelialized

4.FOURTH WEEK WOUND..

.Continued deposition and remodelling resorption of the bone filling alveolar socket.

.Radiographic evidence of bone formation doesnt become prominent until 6th or 8th week.

Complications of healing of extraction wound..

1.DRY SOCKET.

2.FIBROUS UNION.

DRY SOCKET..

.The most common and painful complication in the healing of human extraction wound is alveolar osteitis or dry socket..

.The condition is extremely painful without suppuration and the presence of foul order.

.It is more commonly associated with difficult and traumatic extractions like the removal of impacted third molars

Mechanism..Infection/trauma inflammation of bone marrow release tissue activators plasminogen plasmin lysis of fibrin kinin formation dissolution of blood clot

PAIN

HEALING OF FRACTURE,,Major phases occur;1.REACTIVE PHASE .Fracture and inflammation .Granulation tissue formation

2.REPARATIVE PHASE.. .Callus formation .Lamellar bone deposition

3.REMODELLING PHASE..

Healing after gingivectomyGingivectomy?????? Excision of gingiva by removing the disesaed pocket wall thereby exposing the tooth surface which provides the visibility and acessibility that are essential for the complete removal of irritating surface deposits and thorough smoothening of roots

Healing process.The initial response after gingivectomy is clot formation.

.Undelying tissue becomes acutely inflammed with some necrosis..

.Clot is replaced by granulation tissue.

.by 24 hrs,increase in new connective tissue cells mainly angioblasts is seen.

by 3rd day , young fibroblasts are seen.

Highly vascular granulation tissue grows creating new free marginal gingiva and sulcus

Contd..After 12-24 hrs, epithelial cells at margin start to migrate over the granulation tissue separating it from the clot.

.Epithelial cells advance by tumbling action.

.Surface epithelialization is generally completed after 5 to 14 days.