CBCT Helps Evaluate Ostium Location and Patency for Sinus Augmentation

Objectives: Sinus augmentation is typically done to gain bone volume in implant sites that have deficient bone. The total height that needs to be gained is dependent on residual bone height at the implant site. Mucosal thickening can often cause complications in the sinonasal complex if the sinus floor is raised high enough to block the ostium. The objective of this study was to evaluate the patency and location of the ostium in the sino- nasal complex in Cone Beam CT scans (CBCT) of patients with mucosal thickening being considered for sinus augmentation.

Methods: A total of 200 Sino-nasal complexes from CBCT scans of 100 patients (50 dentate and 50 edentulous) with mucosal thickening in the maxillary sinus were retrospectively evaluated. Total height of the alveolar ridge was measured at the maxillary first molar region on both. From the floor of the sinus, the height of the mucosal thickening and the height from the floor of the sinus to the ostium were measured. By calculating the height from the superior most aspect of the mucosal thickening to the ostium, the total amount of height available for augmentation was calculated.

Results: Descriptive statistics were done. Available alveolar height in dentate patients was 9.22±3.27mm, 6.65±4.02 in edentulous patients. The total height of the sinus from the floor to the ostium was 25.60 mm, average mucosal thickening was 6.34 mm. From the superior aspect of the thickening to the ostium, the height of the sinus was 23.77 mm. This provided the total amount of available height that could be potentially gained by doing a sinus lift procedure.

Conclusions: CBCT can reliably help in evaluating the height available to augment the maxillary sinus without compromising the patency of the ostium and can aid in better treatment planning of implant sites.