3.08.23 Magda_ horizontal and vertical GBR Flashcards
How much bone is lost during spontaneous healing after extraction?
~40% vertical height and ~60% horizontal width is lost in the 1st year.
After 1 year, it’s about 0.1 mm/year in the maxilla, and 0.4 mm/year in the mandible.
How does thin vs thick buccal bone affect the final soft tissue volume?
Chappuis 2000 (Buser group)
Facial bone thickness ≤ 1mm (Thin): 7x increase in soft tissue thickness - can do GBR after the collapse happens. Vertical loss 62% (7.5 mm)
Facial bone > 1mm (Thick): no soft tissue change. Vertical loss 9% (1.1 mm)
What is the critical buccal bone thickness?
Spray 2000
1.8 mm
Examined >3000 implants - buccal bone measured after osteotomy prep and at 2nd stage.
Bone loss will occur if the thickness is < 1.8mm.
Bone will stay the same, or increase, if > 1.8 mm
What are the different ridge deficiency classifications?
Siebert ‘83: Class I, II, III
Allen ‘85: Type B “Buccolingual”, Type A “Apico-coronal”, Type C “Combination”
Wang & Al-Shammari ‘02: H “Horizontal”, V “Vertical”, C “Combination”
Subcategories for “combination” - Small (≤ 3mm), Medium (4-6mm), Large ≥ 7mm
What are techniques to obtain primary closure?
Greenstein ‘09
Flap advancement technique depends on how much advancement you need.
Minor (< 3mm) - Extend the full-thickness flap beyond the MGJ.
Moderate (3-6mm) - 2 vertical releasing incisions, and add 1mm periosteum scoring as needed
Major (≥ 7mm) - Deeper periosteal scoring of 3-5 mm into submucosa; and/or split-thickness flaps
Park ‘11
First vertical incision: 1.1 mm
Second vertical: 1.9mm
Periosteal releasing incision: 5.5 mm
Plonka ‘17
Similar to the above, but adds clinical applications:
Minor advancement (< 3 mm): Esthetic buccal flaps, Mucogingival pouch flaps, Periosteal pocket flaps.
Moderate advancement (4-6mm): Buccal pedicle, lingual pedicle, palatal advanced flap, lateral pedicle flap
Major advancement (≥ 7 mm): Hockey stick flap, remote flap, double flap, multilayer approaches
What are the resorption times of BioMend, BioMend Extend, and BioGide?
BioMend: 6-8wks
* Bovine tendon - 100% type I collagen.
BioMend Extend: 18wks (about 4 months)
* Bovine tendon - 100% type I collagen.
BioGide: 24 weeks (6 months)
* Porcine dermis - Types I and III collagen
How does cross-linked vs non-crosslinked collagen membranes compare on bone?
Garcia ‘17
NSSD between the groups
However, crosslinked had a slightly greater exposure risk.
Tissue integration and compatibility may be better in noncrosslinked
How does cross-linked vs non-crosslinked collagen membranes compare on bone?
Garcia ‘17
NSSD between the groups
However, crosslinked had a slightly greater exposure risk.
Tissue integration and compatibility may be better in noncrosslinked
What types of fixation are available for membrane fixation? What are suturing techniques to use?
Screws - Need bone penetration; membrane might twist. Can either leave it or remove it.
Pins - Need bone penetration; Patient sometimes complains of trauma. Can either leave it or remove it.
Absorbable sutures - Need split thickness somewhere to fixate the sutures. Sutures may become loose at flap closure. Self absorb over time.
Urban ‘16 - Double layer suturing technique. Grab the periosteum only with the suture (both buccally and lingually) and tie; this will “compress” the membrane over the graft and reduce tension for the final flap closure.
What is the horizontal bone augmentation decision tree?
Fu & Wang ‘11
Buccolingual bone width:
≥ 3.5 mm:
* If primary implant stability: do simultaneous “sandwich” bone augmentation
* If no primary stability: Staged GBR and place implant later
< 3.5 mm: Primary stability is not possible.
Do onlay graft. If tissue thickness is ≥ 1.5 mm: (Mandible: autogenous; Maxilla: allogenic)
4-5 mm: Ridge split or expansion
This was explained a bit better by Yu & Wang ‘22
What is the Sandwich bone augmentation? And, does adding a 2nd membrane provide additional benefit?
Wang ‘04 - Sandwich technique
Different layers to help avoid peri-implantitis in the future after implant placement.
Implant surface -> autogenous layer -> allograft -> bovine bone -> collagen membrane
Wen ‘18 Modified Sandwich technique
Same as above, but the allograft layer uses cancellous on the inner, and cortical on the outer
Fu & Wang ‘13
Compared Sandwich technique vs. Sandwich + extra membrane (bovine pericardium).
Finding: Additional membrane reduced bone resorption at 2, 4 ,6mm apical to the bone crest.
What is contour bone augmentation?
Buser ‘08
Implant -> autogenous layer-> DBBM -> Double layer noncrosslinked collagen membrane
What is the sausage bone graft technique?
Urban ‘11
Autogenous bone, either alone or in combination with the anorganic bovine bone (BioOss) 1:1 ratio
Use resorbable membrane and pins
What is the Periosteal Pocket flap technique for GBR?
Steigmann ‘92
Used for horizontal GBR
Use the periosteum as a “pocket” to contain the apical part of the graft
What is the ridge split technique & how effective is it?
Simion ‘92
Describes the ridge split technique
Splitting alveolar ridge longitudinally
Using chisel
Greenstick fracture
Surgical fracture extend to the depth 5-7 mm
3-4 mm intact bone left apical to the fracture
Milinkovic ‘14
Ridge split complications: 6.8%
Survival rate 97%
