The aim of this study is to investigate the volumetric measurements of the maxillary sinus among Indonesian population through computed tomography (CT) scan semi-automated segmentation. This project collected 802 retrospective head CT scan archives from Department of Radiology, Hasan Sadikin Hospital, Bandung, Indonesia between 2019–2020. Patients with craniofacial anomalies/pathology fracture in proximity of the maxillary sinuses, and mediocre image quality were excluded from this study resulting only 97 CT scan archives (194 maxillary sinuses; 52 males; 45 females; age range 0–25 years old). Three-dimensional craniofacial structures were reconstructed and volumetric measurements of the maxillary sinus were computed through semi-automated segmentation using ITK-SNAP. This study recorded the initial phase of maxillary sinus pneumatization during infancy. The maxillary sinus developed until reaching the maximum of average maxillary sinus volume at 13,278.73 mm 3 in 16 to 20 years old group in which afterwards fell to 12,325.21 mm 3 . There was no difference found between right and left maxillary sinus volume. This study revealed that the pneumatization of maxillary sinus begin during infancy and climb until reaching the second decade of life, in which after that slowly decrease. Moreover, no difference between right and left maxillary sinus volume was detected. The volumetric dimension of maxillary sinus presented in this study may serve as the basis knowledge surgical intervention of maxillary sinus and its related structures.

Purpose: Spatial perception is an essential skill for professional dentists. The objective of this study was to observe the spatial ability, as well as anatomy module grades, of dental students at a dental education center in Indonesia and relate these to gender and cohort. Methods: A cross-sectional study was carried out where dental students in years (cohorts) 1, 2, 4–6 were invited to take the Revised Purdue Spatial Visualization Test (PSVT-R) and the redrawn Vandenberg and Kuse Mental Rotation Test (MRT) in order to assess spatial ability. In addition, the 1st- and 2nd-year dental students carried out gross anatomy assessments. Spatial ability test results were compared using an independent t-test to detect gender differences, one-way analysis of variance to inspect cohort differences, and correlation relative to anatomy module scores. Results: A total of 326 dental students voluntarily participated. Statistically significant gender differences were found in both spatial ability tests in the overall sample (PSVT-R: p<0.001; MRT: p=0.001). When the 1st- and 2nd-year dental students were pooled, significant gender differences were detected, in which males scored higher than females in both spatial ability tests (PSVT-R: p<0.001; MRT: p=0.003). In anatomy, however, females scored higher than the males (p=0.005). In addition, there were weak to moderate, but significant correlations between spatial ability tests and anatomy scores. Conclusion This study indicated that spatial ability may not be the only factor predicting the academic performance of dental students. However, dental students with low spatial ability scores may need supplementary educational techniques when learning specific spatial tasks.