Guided bone regeneration of large mandibular defects in a primate model

Area of Science:

• Oral surgery
• Regenerative medicine
• Biomaterials science

Background:

• Guided bone regeneration (GBR) is a technique used to repair large bone voids.
• Previous studies demonstrated GBR effectiveness in primate mandibles following en bloc resection.
• This study investigates the optimal duration for membrane placement in GBR procedures.

Purpose of the Study:

• To determine the minimum duration required for membranes to be in situ for effective guided bone regeneration.
• To evaluate the impact of membrane exposure time on bone fill in standardized mandibular defects.
• To assess bone maturity following different membrane placement intervals.

Main Methods:

• Standardized 8 x 19 mm mandibular defects were created in 18 adult male Macaca mulatta monkeys.
• Reinforced ePTFE membranes were secured with mini screws and sutures for 1 to 12 months.
• Bone regeneration was assessed using clinical observation, digital subtraction radiology, tetracycline labeling, and histomorphometry.

Main Results:

• No significant bone gain was observed with membranes in place for 1 month or less.
• Substantial bone gain (over 90% defect fill) was achieved when membranes remained for 2 to 12 months (P <0.0001).
• No significant difference in bone gain was found between 2 and 12 months of membrane placement; bone produced after 2 months was mature.

Conclusions:

• Membrane placement for 1 month or less yields minimal bone gain in guided bone regeneration.
• A minimum of 2 months of membrane placement is necessary for significant and mature bone regeneration.
• The duration of membrane placement from 2 to 12 months does not significantly impact the final bone fill percentage.