Week 7- Perio Surgery Furcations, Bone Grafts, GTR Flashcards
What is the issue with furcation involved teeth?
Tend to respond less favourable to non-surgical perio therapy and have reduced prognosis.
What are surgical tx options for furcation involved teeth?
- Resective surgery
- Furcation plasty
- Hemi-section, root resection, bicuspidization
- Regenerative surgery
What is the classification for furcation involvement?
- Grade I: incipient, catch in furcation
- Grade II: bone loss, not through and through ‘cul-de-sac’
- Grade III: bone loss through and through
What is the perio pocket in a furcation lesion influenced by?
- Anatomy of soft tissue (thick, thin)
- Bone (horizontal and angular loss)
- Inter-radicular anatomy of tooth
What does furcation plasty involve?
- Odontoplasty (reshaping tooth)
- Osteoplasty (reshaping bone)
- Gingivoplasty (reshaping gingiva) to enhance pocket and furcation access following open debridement.
What are the steps of furcation plasty?
- Flap to access inter-radicular area
- Odontoplasty to widen furcation entrance
- Osteoplasty to reduce or eliminate the intra-bony defect and decrease thickness of bone.
- Positioning flap at level of alveolar bone crest.
What is the goal for furcation plasty?
Improved access for self-care and professional supportive care should result
What teeth should aggressive odontoplasty be avoided on and why?
Aggressive odontoplasty should be avoided on vital teeth due to risk of hypersensitivity
What furcation involved teeth can receive tunnel preparation?
Md molars with deep grade II and III furcation defects
What is the rationale for hemi-section, root resection and bicuspidization?
Complete elimination of furcation defect. Involves a multidisciplinary approach and aims to preserve tooth or part of it
When is endo tx completed when hemi-section, root resection and bucuspidization are undertaken?
- Endo done before surgery
- Occasionally, decision to resect root is made during surgery, in which case endo tx is done along with surgery.
What is hemisection?
Sectioning tooth in 2 and removing one half of it (can do cantilever off remaining segment)
What teeth is hemi-section vs root resection done in?
- Hemi-section: lower molar
- Root resection: upper molar
What is this procedure?
Hemi-section
When is hemi-section indicated?
- Severe bone loss around one root
- Perforations during endo
What is root resection?
Removal of one or two roots (with poorest prognosis)
What is this procedure?
Root resection
What is bicuspidization?
Splitting tooth in 2 and retaining both sections
What is this procedure?
Bicuspidization
What are the steps of hemi-section, root resection and bicuspidization?
- Mucoperiosteal flap to expose furcation area
- Sectioning root or tooth with straight line cut
- Careful removal of root (root resection), tooth section (hemisection). Non for bicuspidization.
- Re-positioning of flaps at level of bone crest.
What are failures for hemi-section, root resection and bicuspidization often associated with?
- Usually due to non-periodontal complications so care should be taken to ensure sound endo therapy and a balanced occlusion
- Remaining roots should have adequate bone support
What is regenerative surgery?
Regeneration of periodontal defects involves formation of new cementum, new attachment periodontal fibers and new bone that was destroyed by perio disease.
How can true regeneration be verified?
Only via histologic evaluation by removing tooth and bone. No way to confirm clinically.
What can you confirm by doing re-entry surgery after regenerative surgery?
Can measure bone fill but cannot ascertain if new cementum or periodontal fibers have formed.
What are the possible healing outcomes after flap surgery?
- Long junctional epithelium
- Connective tissue adhesion & root resorption
- Root resorption & ankylosis
- New connective tissue attachment
What are indications for bone grafts?
- Infra/intra bony defects (3 and 2 walled defects
- Grade II furcation involvement
- Preparation of site for implant (GBR)
- In combo with GTR procedures
What are contraindications for bone grafts?
- Horizontal bony defects associated with teeth
- Lack of soft tissue coverage
- Pt with poor plaque control
- Systemic issues suck as smoking and poor general health
What are the 4 types of bone grafts in order of best to worst for healing?
- Autogenous graft ( tissue from self)
- Allograft (tissue from another human)
- Xenograft (tissue derived from animal)
- Alloplast (synthetic)
Properties of osteogenic bone grafts
Formation of new bone from living cells transplanted within the graft e.g. autographs
What is osteoinductive bone graft?
Graft sends signals to attract, proliferate and differentiate early-lineage cells cable of forming bone e.g. allografts
What is osteoconductive bone graft?
Graft serves as scaffold onto which bone cell can attach, migrate, grow and/or divide e.g. allografts and some xenografts
What are characteristics of autographs?
- Gold standard (most compatible & best quality)
- Blocks or chips can be scraped off bone surface (can control how much bone is harvested)
- Intra-oral or extra-oral sites can be harvested
What are the reasons for extra-oral autograph bone graft, what are the cons and where are the common sites?
- If larger quantity of bone is required (e.g. jaw reconstruction)
- Increased morbidity (GA)
- Theatre cost
Common sites: hip bone, ribs, fibula, tibia
What are the reasons for intra-oral autograph bone graft, what are the pros/cons and where are the common sites?
- When you need limited quantity of bone
- Lesser morbidity (under LA)
- Surgical expertise
Possible sites: exo sites, retromolar area, md ramus, md symphysis. mx tuberosity, tori
What is DFDB?
Decalcified Freeze-Dried Bone
- Type of allograft
- Very compatible
What is xenograft?
Protein extraction of bovine bone to produce porous bone mineral hydroxyapatite (Bio-Oss is common product)
What is selective repopulation GTR?
Selective repopulation blocks epithelial and connective tissue, to allow only PDL and bone to fill space.
What are the steps of GTR?
What are examples of non-resorbable membranes?
- PTFE Membranes (Gore-Tex)
- Titanium reinforced dense PTFE (Cytoplast)
What are characteristics of non-resorbable membranes?
- Needs 2nd surgery to remove
- Exposure can lead to infection
- Used mainly in GBR
What is this procedure?
Placement of non-resorbable membrane for GBR (socket preservation)
What are the 3 types of resorbable membranes?
- Collagen
- Polylactic acid
- Polyglycolic acid
What are advantages of resorbable membranes?
- Eliminates need for 2nd surgery
- More tissue friendly
- Enhances tissue coverage
- Resist microbial colonisation
What are disadvantages of resorbable membranes?
- May elicit immune or inflammatory response
- Time of resorption cannot be controlled
What is this?
Bio-Glide (Resorbable collagen membrane)
Give an example of each type of bone graft
- Autograph: hip, retromolar area
- Allograft: DFDB
- Xenograft: BioOss
- Alloplast: Perioglas
