Volumetric change after maxillary sinus floor elevation using absorbable collagen sponge: a retrospective cohort study

Objectives: To evaluate changes in bone volume induced by absorbable collagen sponge (ACS) use during maxillary sinus floor elevation and to identify associated factors. Patients and Methods: After elevating the sinus membrane through a crestal approach (CA) or lateral approach (LA), ACS (AteloPlug; Bioland) was inserted, and dental implants were placed simultaneously. Changes in bone volume at 12 months were evaluated by three-dimensional (3D) analyses of cone-beam computed tomography images. Factors including age, sex, smoking status, span, number of ACSs, and perforation were assessed for associations with changes in sinus bone volume using uni- and multivariable analyses based on the generalized estimating equation. Results: Medical records of 108 patients were collected and retrospectively evaluated, with 135 regions of interest defined (CA, 45; LA, 90). The changes in bone volume at the sinus floor were 159.38±134.52 mm3 and 486.83±253.14 mm3 in the CA and LA groups, respectively. Bone volume changes in the CA group were significantly affected by the number of ACSs (P<0.001) and perforation of the sinus membrane (P<0.001), whereas bone volume changes in the LA group were significantly affected by the number of ACSs (P=0.001). Conclusion: Use of ACS for maxillary sinus elevation resulted in detection of new bone formation in 3D analysis. Clinicians can ensure stable amounts of bone formation by inserting an adequate number of ACSs.