Sinus floor elevation in sites with a perforated schneiderian membrane: What is the effect of placing a collagen membrane in a rabbit model?

Abstract

Objective To investigate the healing following sinus grafting in sites with a perforated schneiderian membrane repaired using a collagen membrane, compared to control sites without membrane perforation. Materials & Methods Following elevation of the sinus membrane in 16 rabbits, each sinus was assigned to one of the following groups: (a) intentional schneiderian membrane perforation, followed by the placement of a collagen membrane and bone grafting (group SMP) and (b) bone grafting without a perforation of the schneiderian membrane and without a collagen membrane placement (control group). At 2 and 4 weeks (n = 8 for each time-point), microcomputed tomographic (micro-CT) and histomorphometric analyses were performed. Results Overall new bone formation in group SMP was significantly delayed compared to the control group at 2 and 4 weeks (1.58 +/- 1.25% vs. 9.23 +/- 2.69% at 2 weeks, 10.43 +/- 3.55 vs. 17.86 +/- 4.11% at 4 weeks, p < 0.05). At 2 weeks, new bone formation for the areas close to lateral (1.19 +/- 2.02%) and medial sinus bone walls (3.17 +/- 1.98%) was markedly delayed in group SMP compared to the control group (13.08 +/- 6.13% and 12.75 +/- 5.63%, respectively, p < 0.05), but there was no statistical difference in those areas at 4 weeks (p > 0.05). The augmented volumes at 2 and 4 weeks were not statistically significantly different in both groups. Conclusion The perforation of the schneiderian membrane and the repair using a collagen membrane delayed new bone formation in the augmented sinuses. However, the extension of the collagen membrane on the sinus bone walls was also attributable to this delayed bone formation.