Radiographic Analysis of Bone Graft Changes and Anatomical Factors Influencing Maxillary Sinus Floor Augmentation

OBJECTIVES: This study aimed to investigate the role of anatomical factors on the outcomes of lateral sinus floor augmentation with simultaneous implant placement using cone-beam computed tomography (CBCT) images. METHODS: This retrospective study evaluated 80 patients who underwent a sinus lift procedure with simultaneous implant placement and Bio-Oss particles using the lateral window approach. The patients underwent CBCT scans preoperatively, immediately, and 6 months after surgery. CBCT images were used to measure bone graft changes and anatomical features, including sinus width (SW), sinus angle, Schneiderian membrane thickness (Tm), and sinus floor morphology. Descriptive statistics and multiple linear regression models were used to investigate the correlations between these features. RESULTS: The linear changes in apical bone grafts are shown below: apical bone grafts height loss of the implant (aBGHL, median [interquartile range, IQR]: 1.00 [1.53] mm), bone and bone grafts height loss 2 mm away from the implant root horizontally (BGHL, median [IQR]: 1.14 [1.61] mm), apical bone grafts width loss of the implant (aBGWL, median [IQR]: 1.60 [4.15] mm), and bone grafts width loss 2 mm below the implant root (BGWL, median [IQR]: 0.80 [2.00] mm). Both aBGHL and BGHL were positively correlated with SW and Tm, while aBGWL and BGWL were primarily correlated with SW in a series of sequentially adjusted multivariable models. CONCLUSION: During the early bone remodelling phase, SW plays a pivotal role in the linear resorption of bone grafts, while Tm primarily influences the loss of bone graft height. CLINICAL RELEVANCE: The results suggest that sinuses with a wide bucco-palatal bony wall distance and a thick Schneiderian membrane are more likely to experience greater bone substitute loss after sinus floor augmentation. These findings will aid clinicians in the selection of implant sites, as well as determining the type and quantity of bone grafting materials.