Multivariable analysis of use of absorbable collagen sponge graft for maxillary sinus floor elevation and augmentation.

Background/purpose: Various studies have shown that use of absorbable collagen sponge (ACS) in maxillary sinus augmentation promotes new bone formation. This study aimed to assess changes in bone height of the maxillary sinus floor and to identify factors associated with these changes when performing sinus augmentation using ACS. Materials and methods: This retrospective study included patients who underwent simultaneous implant placement and maxillary sinus augmentation using ACS through a crestal (CA) or lateral (LA) approach. Changes in bone height at 12 months (G2, primary outcomes) were evaluated by cone-beam computed tomography. Factors associated with these changes were evaluated, including age, sex, smoking, location, span, number of ACSs, sinus perforation, sinus membrane elevation height, and residual bone height. Variables significantly associated with G2 were evaluated by multivariable analyses based on the generalized estimating equation. Results: Overall, 108 patients were evaluated, including at 182 implant sites (CA, 53; LA, 129). G2 was 2.16 ± 1.51 mm (residual bone height, 8.11 ± 1.58 mm) and 4.62 ± 2.04 mm (residual bone height, 5.54 ± 2.52 mm) in the CA and LA, respectively ( Conclusion: Clinicians need to make efforts to sufficiently elevate the sinus membrane and minimize perforations in order to achieve desired levels of new bone formation.