Wound Healing- Paquette Flashcards
What are the goals of periodontal treatment?
- Remove irritants from roots
- eliminate exogenous bacterial infection from the periodontium
- reduce or eliminate pocket depth
- Reshape hard and soft tissue→regain harmonious topography
Repair vs Regeneration
-
Repair:
- Architecture & Function are NOT completely restored
-
Regeneration:
- the architecture & function are completely restored
What are the factors involved in Periodontal Tissue Repair & Regeneration?
- Scaffolds
- Cells
- Growth Factors
- Blood Supply
What are the periodontal procedures that involve wound healing?
- SRP
- Flap Surgery
- Guided Tissue Regeneration
- Guided Bone Regeneration
- Tooth Extraction
- Soft tissue Grafts
What is wound healing?
- Dynamic, interactive process
- involves:
- soluble mediators
- blood cells
- extracellular matrix
- parenchymal cells
What biological processes does wound healing involve?
- Inflammation
- Epithelialization
- Granulation tissue formation
- Neovascularization
- Differentiation
What are the phases of wound healing?
- Inflammation
- Granulation Tissue Formation
- Tissue Remodeling
- Matrix formation/remodeling
Healing by primary vs secondary intension
- Primary:
- Little loss of tissue
- wound margins are close together
- unimpeded repair
- blood clot quickly organized
- Secondary:
- A lot of tissue loss
- Wound filled w/granulation tissue
- A lot of tissue loss
Wound Healing: Molecular changing stages
Injury
- Sealing Stage
- Platelet Aggregation
- Blood Clot
- Edema
- Fibrin forms
- Growing Stage
- Fibroblasts enter
- Collagen Synthesis
- Finishing (Remodeling) Stage
- Fibrinolysis
- Oxygenation & Ntr Perfusion
- Epiphelialization
Growth Factors
- Diverse group of polypeptide molecules
- released by cells in the inflamed area
- regulate growth & development of organs
- Types:
- Autocrine
- Paracrine
- Endocrine
What cells can secrete growth factors?
- Macrophages
- Endothelial Cells
- Fibroblasts
- platelets
What are the different Growth Factors
- PDGF
- Platelet Driven Growth Factor
- IGF
- Insulin-Like Growth Factor
- FGF
- Fibroblast Growth Factor
- TGF
- Transforming Growth Factor
- VEGF
- Vascular Endothelial Growth Factor
Healing after SRP: Process
- Immediately after:
- blood clot fills gingival sulcus
- Hemorrhaging within the tissue
- PMN Leukocytes on wound surface
- within 2 days:
- Granulation tissue
- 5-7 days:
- epithelialization of CT in sulcus
Healing after SRP: Clinical Appearance
- Immediately after:
- Gingiva appears:
- hemorrhagic
- bright red
- Gingiva appears:
- 2-7 days:
- Gingiva
- redder than normal but less than previous days
- Gingiva margin:
- Reduced height
- Gingiva
- After 2 weeks:
- Gingiva:
- normal color, consistency, surface texture, contour
- Gingival margin:
- well adapted to tooth
- Immature collagen appears
- Gingiva:
What does healing after SRP result in?
Form long junctional epithelium
Healing after SRP: Will new CT fibers reform and insert into new cementum?
- Possible-coronal to the PDL
Healing after SRP: How resistant will this healing be to future bacterial challenges?
Similar to a non-diseased site
Healing after Gingivectomy: Timeline
- Initial Response
- form protective blood clot
- acute inflammation
- necrosis of underlying tissue
- Granulation tissue replaces clot
- 12-24 hours:
- Epithelial cells begin migrating to wound site
- 24 hours:
- CT cells (Angioblasts) Migrate to wound site
- 36 hours:
- Peak epithelial cell activity
- fixed to fibrin layer by hemidesmosomes & new basement membrane
- Peak epithelial cell activity
- day 3:
- Fibroblasts appear
- Granulation tissue grows coronally
- creates new gingival margin and sulcus
- Day 5-14:
- Epithelium is made w/less keratin than before surgery
- Week 4:
- Epithelium complete repair
- Week 7
- CT complete repair
What layer does the epithelial cells arise from during wound closure?
Stratum Spinosum
Healing after Gingtivectomy: How long does it take the epithelium vs the CT to become completely repaired?
- Epithelium
- 4 weeks
- CT
- 7 weeks
Healing After Flap Surgery: Soft Tissue Reaction timeline
- 0-24 hours:
- Blood clot w/granulation cells connects the flap to the tooth/bone
- 24-72 hours:
- space b/w tooth and flap lessen
- Epithelial cells migrate
- 1 week:
- epithelial attachment to root
- hemidesmosomes
- basal lamina
- Blood clot is replaced by granulation tissue
- epithelial attachment to root
- 2 weeks:
- Collagen aligns parallel to tooth
- Weak Flap Connection to tooth/bone due to immature collagen fibers
- Normal Clinical Appearance
- 4 weeks/1 month:
- Gingival Crevice full epithelialized w/well defined epithelial attachment
- Functional collagen fibers are mature
What is granulation tissue derived from?
- Gingival CT
- Bone marrow
- PDL
Healing After Osteoplasty: Bone Reaction time line
- day 1-3:
- Superficial bone necrosis
- Day 4-6:
- Peak Osteoclastic activity (resorption)
- After 6 days:
- Osteoclastic activity declines
- Bone Loss=1 mm
- Week 3-4:
- Peak Bone Repair
- new bone formation
- osteoblast activity 1 year after
- Cancellous Bone
- Interdental area
- no net bone loss
- Radicular Bone
- mild marginal loss
- Peak Bone Repair
Major Growth Factors In wound healing:
Fibroblast Proliferation
Fibroblast Migration
Chemotactic For Macrophages
Neovascularization
Collagen Synthesis
Colagen Secretion
