The aim of this study was to examine the prevalence, location and morphology of maxillary sinus septa, and in particular sagittally orientated forms, which cannot be visualized by classic 2D x-rays. Thereby authors would like to provide information about the potential patient group, to be referred for the computed tomography scan before sinus lift procedure. The analysis was based on 216 computed tomography archival images. The exclusion criterion was occurrence of any suspected pathology in the maxillary region. The septa prevalence that was investigated in computed tomography was high (49%) with the mean height of 5.44 mm. The incidence of sagittally orientated septa as a challenge in 2D x-rays was 10%, with the second molar region as the most frequent location. Based on the obtained results and radiation safety principles, the authors suggest that orthopantomogram x-ray may be a sufficient ancillary radiological examination before beginning preimplant surgical procedure in the area of the maxillary sinus.

KEY WORDS: Dental Implants; Sinus Floor Augmentation; Maxillary Sinus.