Histomorphometric analysis of sinus augmentation using bovine bone mineral with two different resorbable membranes.

OBJECTIVE: The purpose of this study was to compare the effects of two different resorbable collagen membranes on new bone formation after sinus grafts with anorganic bovine bone mineral (BBM). MATERIALS AND METHODS: For 64 patients presenting with an initial residual bone height ≤4 mm at the posterior maxilla, the sinus floors were grafted with BBM (Bio-Oss). The lateral windows were covered by one of the two bio-resorbable membranes, Bio-Arm or Bio-Gide. The histomorphometric data were obtained 7-15 months after sinus augmentation at the time of the implant installation. RESULTS: The core biopsy specimens of Bio-Arm (n = 37 sites) and Bio-Gide group (n = 22 sites) were compared. The results showed that the BBM particles were in direct contact with the newly formed bone in all cases. In histomorphometric analysis, the Bio-Gide group showed significantly higher new bone formation (33.3 ± 12%) compared with the Bio-Arm group (26.3 ± 8.1%) (P < 0.05). All the implants survived successfully after a mean follow-up of 35.3 months (range 22-63 months) in the Bio-Arm group and 55.5 months (range 35-66 months) in the Bio-Gide group. The amount of new bone in the specimens did not significantly correlate with the residual bone height at the time of surgery or the length of the healing period. CONCLUSIONS: The type of resorbable membrane did not readily affect the long-term survival of the implants at the grafted sinus. On the other hand, Bio-Gide group showed more new bone formation than the Bio-Arm group, which implied that the function of the membrane can influence the remodeling of the grafted sinus. As the amount of residual bone substitute particle had not decreased significantly over time, the results suggest that the BBM was rarely resorbable for at least 15 months after the surgery.