Retrospective three-dimensional image analysis of morphological changes in maxillary sinus floor augmentation with carbonate apatite

The aim of this retrospective study was to evaluate the three-dimensional morphological stability of carbonate apatite (CO₃Ap) during two-stage maxillary sinus floor augmentation (MSFA). Thirty MSFA procedures in 26 patients were analysed for morphological changes in the grafted materials; CO₃Ap was used as the grafting material in 15 cases and β-tricalcium phosphate (β-TCP) in the other 15 (controls). Changes in the volume ratio (CVR) and the upper surface of the regions grafted (GAUS) were calculated using cone beam computed tomography data obtained immediately after filling and at follow-up (approximately 4 months later). The width of the sinus floor and angle between the lateral and medial sinus walls were measured as potential confounders affecting the volume of the grafted materials. CVR and GAUS were significantly lower in the CO₃Ap group than in the β-TCP group (CVR: 95.6% ± 6.7% vs 81.4% ± 16.5%, respectively, P = 0.008; GAUS: 92.4% ± 6.9% vs 79.3% ± 13.1%, respectively, P = 0.009). The volume of CO₃Ap decreased by 4.4% ± 6.7%, whereas that of β-TCP decreased by 18.6% ± 16.5%. The type of material significantly influenced CVR and GAUS after adjusting for variables. CO₃Ap appears promising for maintaining volume during two-stage MSFA.