4. WOUND REPAIR
EPITHELIALIZATION
Injured epithelium has genetically programmed regenerative ability that allows it
to establish its integrity
Free edges of epith cont. to migrate until it comes into contact with another free
edge of epith
Abrasions (surface epith)
5. e.g
detrimental effect of process of c.inhibition controlling
epithelialization occurs when
o Opening is accidently made into maxillary sinus during tooth
xtraction.
o If epith of sinus wall and oral mucosa is injured ..it begins to
proliferate in both areas….. creating OROANTRAL
FISTULA
6. STAGES OF WOUND
HEALING
TREE BASIC STAGES:
INFLAMMATORY STAGE (reactive phase)
PROLIFREATIVE STAGE (regenarative or reparative)
fibroplastic phase
REMODELLING STAGE (maturational phase)
8. VASCULAR PHASE
initial vasoconstriction of disrupted vessels…..blood coagulation
Histamine , prostaglandins elaborate by WBCs
…vasodilation…which allows plasma to leak and leukocytes to
migrate into interstitial tissues
9. Fibrin from plasma causes lymphatic obstruction ..accumulate in the
area of injury ….EDEMA
11. CELLULAR PHASE
Triggered by complement products .... act as chemotactic factors and cause
neutrophils…
o Margination ….
o Diapedesis
o Contact wd foreign material …. Degranulation
o Lysosomal enzymes …destroy foreign materials ..digest necrotic tissue also
aided by monocytes..macrophages
12. Wd time lymphocytes accumulate at site of tissue injury
B lymphocytes
o able to recognise antigenic material produce antibodies that assist
in identifying foreign materials and interact wd complements to lyse
foreign cells
T lymphocytes
o Helper T cells
o Suppressor T cells
o Cytotoxic T cells
13. LAG phase
During ds phase no significant gain in wound strength occurs ..little
collegen deposition
Fibrin … material holding wound…..little tensile strength
14. PROLIFATIVE STAGE
The combined process of epithelialization , firoplasia and
angiogenesis accur in ordr to replace dead
and missing tissue
Lasts for 2 days to 3 weeks
15. FIBROPLASTIC PHASE
Strands of fibrin… form latticework…fibroblast can begin laying down ground
substance and tropocollagen
Ground substance (mucopolysaccharides )…. Cement collagen fibers
Fibroblasts secrete fibronectin…helps
Stabilize fibrin
Assist in recognizing foreign material
Act as chemotactic factor for fibroblasts
Helps to guide macrophages along fibrin strands for phagocytosis
of fibrin
16. Fibroblasts deposit tropocollagen….
Collagen produced in xcessive amounts nd laid down in
haphazard manner …. Effectiveness of collagen to
produce wound strength….rapidly inc during fibroplastic
stage , which normally lasts for 2-3 weeks.
17. If Wound is placed under tension
o at the beginning of fibroplasia
o Near the end of fibroplasia
o At the end of fibroplastic
stage……stiff…..erythematous…able
to wdstand 70-80% tension
18. REMODELLING STAGE
Final stage….many of previous randomly laid collagen fibers are
destroyed as they are replaced by new collagen fibers, which are oriented to
better resist tensile forces of wound
Slowly wound strength ..80-85%
Allows the Scar to soften…
Loss of edema…
19. Wd time … vascularity
…diminishes wound
erythema….Elastin is not replaced in
injured tissue…. loss of flexibility along
scarred area(fig5)
Take 3 weeks to 2 years to complete
20. WOUND CONTRACTION
o Final process….
o edges of wound migrate toward eachothr
o In which edges are not placed in apposition
, wound contracrion diminishes size of wound
Problems
third-degree …develop deforming nd debilitating contractures, if
wounds are not replaced wd skin grafts
Can b lessened by placement of a layer of epith between d free edges
of wound
21.
22. FACTORS THAT IMPAIR
WOUND HEALING
Foreign mateial
3 basic problems
i. Bacteria…..
ii. Nonbacterial foreign material…
iii. Foeign material is often antigenic…
That decreases fibroplasia
Infection
23. Necrotic tissue
causes 2 problems
i. serve as a barrier to ingrowth of reparative cells….
ii. Serves as a protected niche for bacteria….
Include blood…..haematoma…….
Drugs
Nutritional problems
Low temp
Distal aspect of xtremities (reduction of 1-1.5 C 2-3F)
24. Ischemia
Dec blood supply >>> tissue necrosis >>> lessen the delivery to
wound of antibodies, WBCs >>> inc the chances of wound infection
dec delivery of O2 ….nutrients….
Caused by
Tight or incorrectly located sutures, improperly designed flaps, excessive
external or internal pressure on wound, systemic hypotension,
peripheral vascular disease and anaemia
25. Tension
If sutures are used to pull tissues together forcefully, >>> ischemia of
tissues
If sutures are removed too early >>> reopen >>> heal with
scar…w-contraction
If sutures are left in too long in attempt to overcome wound
tension…spread open during remodelling stage…and tract into epith
through which sutures ran will epithelialize and leave permanent
disfiguring marks
26. Edges of wound in which no
tissue loss are placed
Wound in which edges are
closely reapproximated
Healing occur more rapidly wd
low risk of infection
wound repair wd minimum
scar tissue
Tissue loss has occurred so A
gap is left between edges of incision
or laceration
Tissue loss prevents
approximation of wound edges
Healing is slower
Produces more scar formation
HEALING
Primary Intention 2ndy Intention
27. Wound repair lessen amount of
re-epithelialization , collagen
deposition, contraction and remodelling
Primary closure should b
performed in 6-8 hr of trauma
but vascular areas may b closed
upto 24 hrs
e.g
Well repaired lacerations or
incisions, well-reduced bone fracture
A large amount of epithelial
migration, collagen deposition,
contraction and remodelling
Wound is left open and heals by
formation of granulation tissue and
contraction
e.g
Extraction sockets, poorly
reduced fractures, deep ulcers, large
avulsive injuries of any soft tissue
Primay Intention 2ndy Intention
28. HEALING BY
THIRD INTENTION
Delayed closure of wound after a vaiable period of time for which it
been left open
Healing of wounds through the use of tissue grafts to cover large
wounds and bridge the gap between wound edges
