Bone Regeneration After Sinus Floor Elevation in an Intact Sinus or a Sinus With Prior Large Membrane Perforation: A Preclinical Study Using a Rabbit Sinus Model

Aim: To determine bone regeneration following sinus floor elevation (SFE) at sites with or without prior sinus membrane perforation. Materials and Methods: The sinus membranes in the maxillary sinuses of 12 rabbits were intentionally perforated (≥ 5 mm) on one side, followed by application of a collagen matrix. SFE was performed on both sinuses after 8 weeks of healing, presenting two groups: SFE with a previous large sinus membrane perforation (group SFE_Perf), and in an intact sinus (group SFE). The animals were euthanized at 2 and 4 weeks after SFE. Micro-computed tomographic and histomorphometric analyses were performed. Results: The amount of newly formed bone within the augmented area did not differ significantly between the two groups at 2 weeks and 4 weeks (4.7 ± 1.0 mm² vs. 5.3 ± 1.4 mm² and 9.2 ± 1.7 mm² vs. 10.8 ± 2.2 mm², respectively, mean ± SD; p > 0.05). However, the amount of newly formed bone near the middle of the sinus membranes was significantly greater in group SFE than in group SFE_Perf (p < 0.05). There was no significant difference in the augmented volume. Fewer subepithelial glands and denser collagen fibres within the sinus membranes were observed in group SFE_Perf than in group SFE. Conclusions: A large perforation of the sinus membrane followed by an 8-week healing period did not jeopardize new bone formation following SFE.