Comparing the thickness of the membrane between the two genders, males seem to have thicker membranes than females. Vallo et al. 2010, Janner et al. 2011, Ji-Young Yoo et al. 2011, Cakur et al. 2013, and Jildirim et al. 2017 [9, 11, 12, 16, 17] also come to this conclusion. Our study assumed that this difference is of the order of 40%. On the contrary, Pazera et al. 2010 concluded that there is no significant difference between thickness of the mucosa and gender (p = 0.294) [18].

The aforementioned differences can be attributed to the fact that every study has evaluated different populations and has also set different criteria in the selection of their sample.

In our study, there is no statistically significant influence when comparing the thickness of the mucosa and age (p = 0.878). Janner et al. 2010, Vallo et al. 2010, and Jildirim et al. 2017 also come in accordance with our results [12, 16, 17]. The age factor does not seem to affect the anatomical characteristics of the sinus. Unlike a state of inflammation, allergy, smoking of the patient does not affect the sinus thickness or wideness [6].

As regards the width of the maxillary sinus, the mean angle value was found to be 73.4 ± 6.9 °. It seems that there is a tendency towards greater angle values in the male group, but the difference is not statistically significant in order to conclude that wider angles and widths exist in male patients. The aforementioned results can be also associated with the results of the study of Gosau et al. 2009, which showed that female sinuses tend to have lower average volume values than male sinuses [4]. The study of Lozano-Carrascal et al. 2017 also measured the same angle but only in the region of the upper first molar and found a mean value of 73.39 ± 15.23 ° [15]. The present study is more accurate because the mean angle results from three different measurements taken from three different points of the maxillary sinus.