Osseous Regeneration Flashcards
what are the objectives of bone replacement grafting
- regeneration of lost periodontium - new bone, cementum, and PDL
- reduce or eliminate the periodontal pocket
what are the types of bone replacement grafts
- autograft
- allograft
- alloplast
- xenograft
- composite
what is an autograft
tissue transferred from one site to another in the same individual
what is an allograft
tissue transferred between individuals of same species
what is an alloplast
inert material used for graft
what is a xenograft
tissue transferred between individuals of differing species
what is a composite graft
combination of grafts
what are the indications for grafting
- deep vertical defects
- esthetic considerations
- teeth critical to prosthesis
- when anatomy precludes other procedures
- guided tissue regeneration
what are the contraindications for grafting
- poor plaque control
- medically compromised
- poor maintenance compliance
what are the advantages of grafting
- restores lost periodontal tissue
- maintains teeth in healthy functional state
- enhances long term prognosis of teeth
what are the disadvantages of grafting
- technique and material sensitive
- expensive
- may require two surgeries
- unpredictable
- requires ideal wound closure
- longer, more frequent post op care needed
- second surgical site sometimes required
- success decreases significantly in furcations and is defect dependent
what are the biologic responses for bone replacement grafts
- osteogenic
- osteoconductive
- osteoinductive
- osteoproductive
what is an osteogenic repsonse
viable osteoblasts are transplanted
what is a osteoconductive response
scaffold for bone formation
what is an osteoinductive response
release of material to induce bone formation
what is an osteoproductive repsonse
production of bone by a biologic mechanism
what is the healing sequence of bone replacement grafts
- incorporation (clot formation)
- revascularization
- resorption of graft material with release of factors (BMP) to induce bone formation
- bone formation
- bone remodeling and maturation
how do you tell if the defect will be a vertical defect
- amount of cancellous bone present
- if the distance between the roots of the teeth is greater than or 2.5mm then the defects will be a vertical defect
if the distance is less than ____- then horizontal bone loss will occur
2.5mm
what is an infrabony defect and what are the types
- apical to the alveolar crest
- one wall (can be a hemiseptum)
- two wall (crater the most common defect)
- three wall (true infrabony defect)
- combination
the success in regeneration is:
defect dependent
best success seen in what defects
three wall defects
second best success seen in what defects
two wall defects
what type of defects have little to no success
suprabony AKA horizontal bone loss
what are the graft complications
- no regneration
- sequestra
- root resorption (rare)
- donor site problems (at second site)
- infection ( less than 1%)
what are the grafting variables
- pre-scaling or scaling at time of surgery
- local drug delivery before sugery
- flap design
- intramarrow penetration
- hydration of graft material
- root treatment or modification
- use of antibiotics
- endodontics and graft success
- smoking and graft success
what are the introral bone sources
- cortical bone chips - no longer used
- osseous coagulum
- healing extraction socket (timing very important)
- chin or ramus block graft
what are the extraoral bone sources
- iliac crest
- ribs
what are the types of allografts
- freeze dried bone allograft
- demineralized freeze dried bone allograft
- solvent treated
how is safety shown in allografts
in HIV/AIDS donors
what does the inductive ability in allografts depend on
amount of BMP available
what does hydration depend on in allografts
materials and amounts
what are the controversies in allografts
resorption of graft
BMP
what are the types of alloplasts
- calcium sulfate (CapSet)
- calcium phosphates: beta tri-calcium phosphate (resorbable), hydroxyapatite (resorbable and non-resorbable)
- HTR
- bioactive glass ceramics (perioglas, biogran)
what is CaSO4/Regeneration a rationale for
adding calcium sulfate to FDBA
what does CaSO4 do
- binds bone particles to prevent washout
- accelerates bone formation by:
- enhancement of BMP
- providing a course of calcium ions to aid in mineralization
what is bioactive glass composed of
silicon dioxide (45%), calcium oxide (24.5%), sodium oxide (24.5%), and phosphorus pentoxide (6%)
what happens when bioactive glass is implanted in vivo
the pH of the local environment increases more than 10 and a silicon- rich gel is formed on the bioactive ceramic surface with the outer layer serving as a bonding surface for osteogenic cells and collagen fibers
what are the sizes of bioactive glass
- one brand has a particle size of 90-710 micrometers
- other brand has a particle size of 400-355 micrometers
how do bioactive glasses work
formation of hollow calcium phosphate growth chambers occur with this size because phagocytosing cells can penetrate the outer silica gel layer and resorb the gel. this leads to formation of pouches where osteoprogenitor cells can adhere, differentiate and proliferate
bioactive glasses are reported in several articles to have
- superior manageability
- hemostatic properties
- osteoconductive
- may act to retard epithelial downgrowth
what are the types of xenografts
- bovine bone (BioOss)
- bovine bone with cell binding peptide 15 attached (PepGen)
- fetal pig enamel matrix derivative (Emdogain) to induce cementogenesis and bone formation
GTR will provide ______
epithelial exclusion
what are the types of GTR
- interdental denudation
- soft tissue grafts over osseous grafts
- citric acid application
- Micropore filter
- Gore Tex membranes
- resorbable membranes
what is platelet rich plasma
concentration of growth factors
what are the synthetically produced growth factors
- recombinant human platelet derived growth factor (rhPDGF) added to beta tricalcium phosphate
- recombinant bone morphogenetic protein (rBMP) added to beta tri-calcium phosphate edentulous ridges ONLY
