Analysis of the anatomy of the maxillary sinus septum using 3-dimensional computed tomography

Maxillary posterior teeth exhibit a high incidence of periodontal bone and tooth loss. After tooth loss, the edentulous alveolar process of the posterior maxilla is often affected by resorption, which results in loss of vertical bone volume. Moreover, progressive sinus pneumatization leads to a decrease in the alveolar process from the cranial side. The sinus elevation and augmentation surgical technique opened a new way of anchoring endosseous implants despite discernible bone reduction. However, the surgical interventions require in-depth knowledge of maxillary sinus anatomy such as sinus septum and potential variations. The purpose of this study was to investigate the prevalence, location, height, morphology, and orientation of maxillary sinus septa by use of computed tomography (CT) and 3-dimensional imaging.

Two hundred patients undergoing implant treatment at the Yonsei University College of Dentistry, Seoul, South Korea, were randomly selected for analysis of maxillary sinus septa. CT and DentaScan (GE Medical Systems, Milwaukee, WI)-reformatted data from 400 sinuses were analyzed with the Preview program (Infinitt, Seoul, South Korea). Three-dimensional images were rendered for measurement by use of the Accurex program (CyberMed, Seoul, South Korea).

We found 111 septa in 400 maxillary sinuses (27.7%). This corresponded to 37% of the patients. Among total septa, 25 sinus septa (22.5%) were located in the anterior, 51 (45.9%) in the middle, and 35 (31.5%) in the posterior regions. The directional orientation analyses showed that 106 septa were buccopalatal, 4 were sagittal, and 1 was transverse type. The mean septal heights were 7.78 ± 2.99 and 7.89 ± 3.09 mm in the right and left sinuses, respectively.

Three-dimensional CT image analyses may provide useful information that can avoid unnecessary complications during sinus augmentation procedures by facilitating adequate, timely identification of the anatomic structures inherent to the maxillary sinus.