Comparison of four bone substitute types in sinus augmentation with perforated Schneiderian membrane: An experimental study

Background: Collagenated bovine bone mineral (CBBM) is used for maxillary sinus elevation-based augmentation. We compared collagen degradation in cross-linked (CL) CBBM and non-cross-linked (NCL) CBBM (in vitro) and preclinical results in CBBM-CL, CBBM-NCL, deproteinized bovine bone mineral (DBBM), and DBBM with fibrin sealant grafts (in vivo) after repair of perforated Schneiderian membrane (SM). Methods: Collagenase-based degradation rates of CBBM-CL and CBBM-NCL were compared in vitro and in vivo (CBBM-CL, CBBM-NCL, DBBM, and DBBM with fibrin glue; n = 12 defects per group). After bilateral maxillary SM perforation (5 mm) during sinus elevation, we performed bone substitute-based augmentation. At 4 and 12 weeks postoperatively, volumetric, histologic, and histomorphometric analyses were performed. Results: Complete degradation and 33% retention of collagen content after 24 and 72 h were noted in CBBM-NCL and CBBM-CL, respectively. CBBM-NCL demonstrated significant differences in total augmentation volume (TAV) compared to DBBM and DBBM with fibrin glue, as well as in new bone volume (NBV) compared to DBBM with fibrin glue. At 12 weeks, significant differences were observed between CBBM-NCL and DBBM in NBV. There were no significant differences across all groups in vertical bone increase in 4 and 12 weeks. DBBM and DBBM with fibrin glue showed more irregularly shaped patterns than CBBM-CL and CBBM-NCL. At 12 weeks, ossification progressed in all groups. At 4 weeks, DBBM with fibrin glue seemed to demonstrate early ossification at the perforation site in histological observations compared to DBBM alone; however, no differences were observed at 12 weeks. Conclusion: CBBM for perforated SM repair confers bone stability and ossification. CBBM-CL was noninferior to CBBM-NCL in volume stability. The findings indicate that the CL collagen in CBBM-CL contributes to enhanced graft stability over time. Fibrin glue appeared to have a positive effect on early ossification in histological evaluations, but this effect was not evident at 12 weeks. Plain language summary: Collagenated bovine bone mineral (CBBM) is used for maxillary sinus elevation-based augmentation. We compared collagen degradation in cross-linked (CL) CBBM and non-cross-linked (NCL) CBBM (in vitro) and preclinical results in CBBM-CL, CBBM-NCL, deproteinized bovine bone mineral (DBBM), and DBBM with fibrin sealant (in vivo) after repair of perforated Schneiderian membrane (SM). After bilateral maxillary SM perforation (5 mm) during sinus elevation, we performed bone substitute-based augmentation. At 4 and 12 weeks postoperatively, volumetric, histologic, as well as histomorphometric analyses were performed. Based on this study, CL collagen in CBBM-CL contributes to enhanced graft stability over time. Fibrin glue appeared to have a positive effect on early ossification in histological evaluations, but this effect was not evident at 12 weeks.