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%
What are different methods of vertical bone augmentation? How effective are they?
Urban ‘19
Distraction osteogenesis: 8.04 mm gain, 47.3% complications
GBR: 4.18 mm gain, 12.1% complications
Block grafts: 3.46mm gain, 23.9% complications
Overall bone gain of 4.16 mm
What are the different zones of flap advancement?
Urban
Zone I : Retromolar. Use periosteal elevator and reflect from bone
Zone II: High mylohyoid attachment. Identify mylohyoid and use blunt instrument to push the tissue that’s superior to the muscle lingually.
III: Deep mylohyoid - Hockey stick incision; Use blunt side of blade to dissect the tissues
What is the surgical management of Significant Maxillary anterior ridge defects?
Urban ‘16
Type I: Deep vestibule - remote flap + periosteal incision
Type II: Shallow vestibule - Safety flap + papilla shift technique
Type III: Deep vestibule - remote flap + periosteal incision
Type IV: Shallow vestibule - Safety flap + papilla shift technique
How does vertical bone deficiency affect the likelihood of incomplete bone regeneration? What about membrane exposure?
Urban ‘21
Each 1mm addition of height deficiency affects the likelihood of incomplete bone regeneration by 2.5 times.
Simion ‘00
Less bone gain when membrane is exposed (41.6%) compared to non-exposed (96.6%)
How does membrane exposure affect the regeneration rate?
Simion ‘94
ePTFE exposure: reduces regeneration rate from 96.6% to 46.5%
What are the classifications for ePTFE healing problems? What about for dPTFE?
For ePTFE:
Verardi & Simion ‘07
Class I: Small soft tissue fenestration ≤ 3mm
Class II: Wide opening > 3mm
Fontana ‘11
Class I: Small membrane exposure (≤ 3mm) w/o purulent exudate
Class II: Large exposure > 3mm w/o purulent exudate
Class III : Membrane exposure w/ purulent exudate
Class IV: Abscess formation w/o membrane exposure
How does bone height change in implants treated with GBR vs. no GBR?
Machtei ‘01
Only 2 studies in meta-analysis
6 times more bone gain in nonexposed compared with exposed sites
