exam 2 (L9) - osseous regeneration Flashcards
what are 4 possible outcomes of periodontal therapy?
- new attachment (ideal)
- long JE formation (common after SRP)
- bone/root ankylosis
- recurrence of disease
what are 2 types of tissue regeneration used in periodontics?
- bone grafts
- guided tissue regeneration (GTR)
what is GTR?
- guided tissue regeneration
- procedure allowing repopulation of periodontal defect by cells capable of forming nee connective tissue and alveolar bone
- new attachment = cementum + bone + PDL formation
which type of cellular growth is encouraged in GTR, and which type is avoided in GTR?
- want: PDL & bone cells to grow cervically
- avoid: gingival epithelium growing apically
what are the guiding principles of GTR?
- excluded unwanted tissue (epi)
- protect the wanted (GTR materials underneath barrier)
- hold the space
what is required for success of GTR?
- primary soft tissue closure (GE)
- secluded space maintained
- membrane stabilization (synthetic)
- adequate healing time
what are the qualities of an ideal membrane?
- absorbable
- biocompatible
- cell occlusive
- space maintainer
- tissue integration
- clinically manageable
- collagen/mesenchymal turnover is 6 wks, so must maintain membrane for at least that long
what non-resorbable materials are used in GTR?
- ePTFE
- second-stage removal necessary, 4-6 wks post-op
what resorbable materials are used in GTR?
- cross-linked collagen membranes (add Zn for str)
- calcium sulfate
- poly-lactic/poly-galactic acid (PLA/PLG)
- doxycycline 4%
- one-stage surgery, degradation 4-6 wks
what is the 3rd type of material used for GTR?
- functionally graded membranes
+ CL = core layer (proteins)
+ SL = surface layer, w/ 2 surfaces
~ epi-facing = metronidazole incorporated as Ab
~ bone-facing = hydroxyapatite incorporated
what types of space maintainers are used to reinforce the membranes used in GTR?
- tenting screws (scaffolding) - build bone to top
- fillers (bone, collagen w/ growth factors [GF])
- take-away: maintain space!
what biologic mechanisms of graft integration are available?
- osteogenesis (viable cells/cause formation)
- osteoinduction (uncommitted CT cells/starts formation w/ GF)
- osteoconduction (scaffolding/space/allows formation)
what graft material types are available, and what biologic integration mechanisms are available to them?
- autograft (self-source) = OC, OI, OG
- allograft (donor source) = OC, OI
- alloplast/xenograft (synthetic/non-human donor) = OC
what advantages and disadvantages are associated with autogenous grafts (autografts)?
- advantages = osteogenic
- disadvantages:
+ second surgical site
+ membranous bone (IO) vascularizes faster than endochondral bone (EO)
+ membranous bone resorbs slower than endochondral bone
advantages and disadvantages of allografts?
- advantages: availability, no donor site, reduced surgical time, fewer complications
- disadvantages: antigenicity, longer healing, less volume
