3.15.23 Mostafa_GBR complications

Question 1

How effective is GBR? What is the complication rate?

Answer 1

Urban
GBR bone gain: 4.18 mm
Complications: 12.1%
In comparison: Bone grafts gain 3.46mm, complications are 23.9%

Askar
18% complications with GBR

Question 2

What factors affect the likelihood of flap opening of GBR?

Answer 2

Yi-Chi Chao (Dr Wang group)
Opening risk: Lower vs. Higher
* Amount of KT > 3mm vs. < 3mm
* Mucosa thickness >1 mm vs < 1mm
* vestibule depth Adequate vs. Shallow
* Flap flexibility High vs. Low
* Bony defect type Horizontal vs. vertical / combination
* Membrane used Resorbable vs. nonresorbable

Smoking ≥ 1 cig per day: OR: 8 for flap dehiscence (Askar et al)

Diabetes: may affect wound healing (Guo et al - review article on healing in Diabetics)

Age: Older patients heal significantly slower (Engeland et al - clinical study placing standardized 3.5 mm circular wounds on hard palates of volunteers)

Question 3

How commonly does GBR cause neurological complications?

Answer 3

Lin ‘16
Altered sensation:
- Short term (< 10 days) : 13%
- Long-term (> 1 year) : 3%
** Recovery rate of 80% within 6 months.

Prevention/Management: Prescription of corticosteroids (severe nerve damage) and B group vitamins to accelerate nerve regeneration

Question 4

What are the classifications of membrane exposure?

Answer 4

Fontana - Classification for ePTFE
Class I: Small exposure (≤ 3mm) without purulent exudate
* Membrane should not be removed immediately, but rather le in place
for 1 month max.
* Focused hygiene regimen (Topical 0.2% CHX gel 2x/day)

Class II: Large exposure (> 3mm) without purulent exudate)
* Membrane must be removed immediately.
* Flaps must be sutured to allow submerged healing for at least 4-5
month.

Class III: Exposure with purulent exudate (usually within 1st month)
* Membrane must be removed immediately + curettage of infected
particles & inflammatory tissue.
* Flaps must be sutured to allow submerged healing for at least 4-5
month.
* Wait 2-3 months before attempting GBR

Class IV:Abscess formation without exposure (usually within 1st month)
* Membrane must be removed immediately + complete curettage of the
graft.
* Local antibiotic wash + systemic antibiotic administration
* Associated with bacterial contamination of graft or PTFE texture.

Urban: Early vs. Late Exposures
Early Exposure
* Usually result of surgical technique Early membrane removal
* Clinician has to choose the right moment between graft maturation and
bacterial invasion of the graft
* Keep membrane for at least 6 weeks, it will be very likely to maintain GBR
dimensions
* Control with CHX 0.12%

Late Exposure:
If dPTFE, healing is usually uncomplicated.
If Cross linked collagen - slower soft tissue closure and 50% more bone loss.
If resorbable collagen = uncomplicated healing

Question 5

What is the membrane exposure rate for different types of membranes? How does membrane exposure affect bone gain?

Answer 5

Membrane Type / Exposure rate
Native Collagen (Biogide, Oramem) / 16.83%
Cross-linked collagen (Ossix) / 22.64%
ePTFE / 29.3%
Synthetic membranes (PEG) / 39.43%

Garcia
74% more bone gain in sites without membrane exposure

Question 6

What are soft tissue complications?

Answer 6

Sanz-Sanchez
Soft tissue complications (membrane exposure, soft tissue
dehiscence and acute infections or abscesses) weighted
rate of 16.8% (range: 0-45 %)

Class 0 = no dehiscence
Class 1 = up to 4 wks healing
Class 2 = from 4 wks to implant placement at 26 wks
Class 3 = from Implant placement to abutment connection
Class 4 = From abutment connection to implant loading

Question 7

What is the difference between low-grade vs. high-grade infection?

Answer 7

Urban
Low-grade infection:
- Source: residual plaque on neighbouring teeth
- Moderate recurrent swelling of the region and fistula formation but
no purulent exudate
- Develops at diff. time points depending on the type of membrane:
* e-PTFE: 2-3 weeks
* d-PTFE: up to 6 weeks
- Tx: Antibiotics, if not effective à graft removal

High-grade infection:
- Pain and recurrent facial swelling with fistula formation and purulent
exudate at the wound margins.
- Noted in the first 10 days, with rapid spread of infection
- Tx: Surgical + Pharmacological (Antibiotics)