Development of New Formulas for Sex and Age Estimation by Assessing Maxillary Sinus Morphology on CBCT

Background The morphology of the maxillary sinus varies between individuals which could be used in the forensic personal identification process. Methods: In the current study, the CBCT images of the maxillary sinus in 453 patients (217 males, 236 females) aged 14 to 95 years were analyzed. In particular, each left, and right maxillary sinus of the subjects was measured for its maximum height, width, and breadth in 2-D, and volume in 3-D perspectives, and their usefulness for age and sex estimation was examined. Regarding age estimation, because the size of the maxillary sinus increases up to 20s and then decreases over time, two separate age estimation formulas were created, one for subjects in their 14–21 years and the other for those over 22 years old. For each age group, multiple regression formulas were generated using the diameters and volume as explanatory variables and the chronological age as a response variable. This study used 150 cases not included in the study as a validation set for age estimation. Results: Generally, all the diameters and volumes in both sinuses tended to increase till the mid-20s, and then gradually decreased over time. The derived formulas were tested for their accuracy on additional 150 subjects. Plausibly, the model could estimate the age between 14–21 years old with an average accuracy of ± 1.8 years for men and ± 3.2 years for women. Whereas for those over 22 years old, it was possible to estimate the age with an accuracy of ± 11.8 years for males and ± 10.3 years for females, respectively. A comparison of estimated age and chronological age did not show a statistically significant difference(P > 0.05). It was found that the left maxillary sinus had more age groups showing the most significant difference than other measurements between sexes(P < 0.05). The maxillary sinus height may be significantly affected by gender differences. Conclusion: Overall, this study showed the effectiveness of age and sex estimation using the maxillary sinus morphometric analyses.