Axial Triangle of the Maxillary Sinus, and its Surgical Implication with the Position of Septa during Sinus Floor Elevation.

The aim was to measure the convexity of the lateral wall of the maxillary (Mx) sinus and identify the locational distribution of antral septa in relation with the zygomaticomaxillary buttress (ZMB), as a recommendation for another anatomical consideration and surgical modification for sinus floor elevation. A total of 136 patients and their 161 sinuses containing edentulous alveolar ridge were analyzed. The angle between the anterior and lateral walls of the Mx. sinus (LSA), and the angle between the mid-palatal line and the anterior sinus wall (ASA) was measured. The mean LSA and ASA were 105.9 ˚ (±9.86) and 58.4 ˚ (±6.43), respectively. No significant difference between the left and right sides was found (LSA, p =0.420; ASA, p =0.564). The prevalence of septa was 37.3%, and it was most frequently noted in the second molar region (32.8%), followed by the first molar, second premolar and retromolar region. The septa which were located posterior to ZMB were most frequently (49.2%), and ZMB was mostly located in the first molar region (66.4%). Narrow LSA may complicate surgical approach to the posterior maxilla, especially sinus elevation should be utilized in the second molar region. Moreover, considering the occasional presence of antral septa, membrane elevation may be complicated when a septum is encountered during the procedure. This result suggests that 3-dimensional examination of the convexity of Mx. sinus should be performed preoperatively to minimize surgical complications.