Regeneration/ Reconstruction & Khoury CH 11 Flashcards
What is the type of grafting material that has been shown to have the most gain in zero wall defects?
Autograft- Iliac bone and marrow have the most osteogenic and regenerative potential
How does decalcification in DFDBA promote maximum osteoinduction
a. only 2% or less residual calcium
b. Demineralization of FDBA will make BMP accessible
What is the Osteogenic potential between cancellous and cortical bone?
a. Cortical = little osteogenic potential
b. Cancellous bone – contains hematopoietic marrow provides better osteogenic potential
Calcium Sulfate–> How is it resorbed when used as a regenerative membrane?
Giant cell reaction
What are the advantages of Resorbable membranes?
- More tissue compatible
- Timing of resorption can be regulated by the amount of cross-linkage
- No second surgery
Which BMP is the primary Osteoinductive protein?
BMP - 2
How does biogide degrade?
Collagenases and subsequently by gelatinases and peptidase
Biogide is a PORCINE resorbable membrane
What are collagen membranes made from?
a. Porcine or bovine
b. Either Type I collagen or a combination of Type I and Type III
What determines is a wound Regenerates vs Repair?
Cell type that repopulates
Regeneration = mesenchymal cells from the PDL or perivascular region of bone
How do you most accurately assess regeneration?
Histology
*Radiographs (standardized)
What does dense HA most likely heal with, histologically?
a. HA is an anorganic Alloplast (Ceramic)
b. Healing occurs through fibrous encapsulation of the HA particles in the intraosseous defect
c. Long Junctional Epithelium and CT attachment
d. Does NOT induce new attachment or bone formation
What are Competence and Progression Factors?
Competence:
a. Prime the cell to enter the cell proliferation cycle
b. PDGF (Platelet derived growth factor)
Progression:
a. Required for cell division
b. IGF-1
What is regeneration?
A. Formation of new bone
B. Cementum
C. Functionally oriented PDL
What is reattachment?
Non-diseased site
What is repair
a. “non-functional types of scar tissue” or new attachment
i. Long Junctional Epithelium
ii. New CT attachment
iii. Ankylosis
What is a root conditioner?
a. Remove smear layer from root surface to expose collagen fibers and opened dentinal tubules.
b. Citric acid: (pH 2-3)
c. Tetracycline and EDTA:
What is osteogenic?
What determines Osteogenic Potential?
a. Has vital cells in the graft
b. Capable of producing new bone
autograft
Osteogenic Potential–> Amount of cancellous bone
What is osteoinductive
a. Induces bone formation by recruiting undifferentiated mesenchymal cells, is mitogenic for pre-osteoblasts, and induces differentiation of these cells into bone forming osteoblasts)
Examples:
b. FDBA c. DFDBA ( demineralization of cortical bone allograft exposed BMP
What is osteoconductive?
a. Acts as scaffold
b. Chemically treated to remove organic components to leave trabecular and porous scaffolding for new bone formation
Example: Xenograft
What is a xenograft
Different species
Scaffold
Osteoconductive
**Longest graft type to resorb
What is alloplast
Inorganic material (synthetic)
What is Guided Tissue Regeneration?
A barrier membrane allowing formation of new periodontium
What are the available membrane types
Resorbable
Non Resorbable
Positives of Non- Resorbable membrane?
a. Space maintenance
b. Clot Protection
c. Barrier Formation—especially in large defects
Negatives of non resorbable membrane?
- 2nd surgery needed
2. Frequent exposure to the oral cavity which leads to failed osseous reconstruction
Positives of Resorbable membrane?
i. More tissue compatible
ii. No 2nd surgery required
iii. Variable times of resorption
REPEAT QUESTION
Negatives of resorbable membrane?
Lack of rigidity/ Tight scaffold
Discuss emdogain
a. It is OSTEOPROMOTIVE
b. True regeneration is possible
c. Harvested from developing porcine teeth, contains a protein preparation that mimics the matrix proteins that induce cementogenesis
Discuss PDGF
Platelet derived growth factor
a. mitogenic and chemotactic factor for mesenchymal cells
b. Type of Competence factor
What are BMPs?
a. Regulatory glycoproteins that are members of the TGF-beta superfamily, and they stimulate mesenchymal stem cells to differentiate into chondroblasts and osteoblasts. (Cartilage and Bone)
Risk of ankylosis
What are some thing that influence the success of regeneration? (4)
i. Plaque control/compliance
ii. Smoking
iii. Tooth/defect factors
iv. Characteristics of defects - depth, width, # of walls
How do resorbable membranes break down?
Resorption
Krebs Cycle
What is the ideal material for ridge preservation?
Osetoconductive
a. Needs to be a scaffold for new bone formation but also minimal in volume at implant placement
What is the point of Decortication, is it worth it?
a. Purpose is to open marrow spaces and allow osteoprogenitor cells to migrate to the site
What factors affect bone graft Osteoinductive potential
Age of Donor
Why does regeneration fail? (3)
- Mechanical Instability
- Poor blood supply
- Competing tissue
When do you graft and bolt?
Ridge < 4 mm wide and you need primary stability
Why do you get early membrane exposure?
- Not using aseptic techniques
- No passive closure
- Inadequate flap mobility
- Smoking
- Diabetes
- Pressure from prosthesis
- Shallow vestibule
What bacteria colonize exposed membranes?
- P Gingivalis
2. Aa
How much Bone resorption of the ridge following tooth extraction?
40-60% horizontal resorption in 3-12 months
What is PASS
Primary closure
Angiogenesis
Space Maintenance
Stability
What is the gain in a ridge split (Distraction Osteogenesis)?
3.5 mm
Ignore this question– wasn’t in our lecture
How long auto/allograft block grafts last?
3/12
Not sure what this means
How much vertical bone can you gain with a block graft?
3 - 5 mm
How do you obtain vertical augmentation?
Onlay block graft
Distraction
Ortho Extrusion
