The aim of this study was to analyze volume parameters of the maxillary sinus based on CBCT data. Further, neighboring anatomical structures and related pathologies were recorded. Overall, the applied volume software used in this study allowed the calculation of the surface area and volume of maxillary sinuses.

In clinics, the radiographic evaluation of the maxillary sinus is obligatory prior to for example sinus floor elevation. Based on this image, the risk for sinus floor elevation and implant placement can be evaluated. The CBCT data can be further used for later implant placement, using guided techniques. CBCT has been proven to be a valuable tool for the analysis of the maxillary sinus as long as the information provided exceeds the radiological risks [4, 5]. Moreover, its accuracy has been proven [6, 7]. Using CBCT images, anatomical structures may be measured in terms of distances as well as volumes.

In this study, the measurements were performed using the SMOP volume software. This software was used earlier by another group for the analysis of the 3D shape of nasopalatine duct cysts [8]. The present study measured both the sinus volume within the osseus borders and the remaining pneumatized sinus volume in cases of obliteration. For the osseus bordered sinus, the measured mean sinus volume was 17.1 cm³, the minimum 4.0 cm³, and the maximum value 28.9 cm³. These measurements are quite comparable to the results of other studies [9, 10]. With regard to sinus obliteration, various studies suggest a potential relationship between periapical lesions and mucosal irritation of the maxillary sinus [11,12,13]. Brook [14] showed that 10–12% of all cases of maxillary sinusitis were caused by teeth. In this study, no association between apical radiolucencies in the upper jaw and sinus obliteration was found. However, it should be mentioned that this study was not designed to observe this relation. In a study, analyzing this association, Nunes et al. [15] selected patients with periapical lesions for a comparison to a group without periapical lesions. Analyzing sinus abnormalities, they showed a relation between periapical lesions and sinus obliteration. Another aspect is the possible association between sinus obliteration and the time of the year. In contrast to other studies [16,17,18], the present study showed no seasonal differences in the presence of obliteration of the maxillary sinus.