Potential use of the cusp and crown areas of the maxillary posterior teeth measured with a two-dimensional stereomicroscope for sex determination.

In this study, we aimed to compare the cusp and crown areas of the maxillary first premolar (PM1), second premolar (PM2), and first molar (M1) in males and females in the Malay population and to formulate sex prediction models. For this purpose, the maxillary posterior teeth of 176 dental cast samples (from 88 males and 88 females) were selected and transformed to two-dimensional digital models using 2D-Hirox KH-7700. Cusp and crown area measurements were obtained using Hirox software by tracing the outermost circumference of the tooth cusps. Statistical analysis included independent t-tests, logistic regression analysis, and receiver-operating characteristic (ROC) curves as well as determination of sensitivity and specificity; analysis was performed with SPSS version 26.0. The significance threshold was set at 0.05. All crown and cusp area measurements were significantly larger in males than in females (p < 0.001). The most sexually dimorphic tooth was the first maxillary molar (mean difference, 10.27 mm2), and the most sexually dimorphic cusp was the mesiopalatal cusp (mean difference, 3.67 mm2) of M1. The sex prediction model had a good accuracy, with 80% of selected cases correctly predicted. Hence, we conclude that the maxillary posterior teeth in the Malay population exhibit significant sexual dimorphism, and this information may be used for sex determination as adjuvants along with other procedures.

Application of two systems to classify the root and canal morphology in the human dentition: A national survey in India.

PURPOSE: To assess the application and accuracy of two systems (Vertucci et al. 1974 and Ahmed et al. 2017) in classifying the root and canal morphology of human dentition among final-year undergraduates, interns, and postgraduate dental students in India. METHODS: The survey was conducted using physical and online presentation modes in two phases. Phase 1; PowerPoint presentation (PPT), describing the most used classification system (Vertucci et al. 1974) and its supplementary types and Ahmed et al. (2017) classification. A single presenter delivered the PPT to participants, using either a projector in an auditorium/seminar hall (face-to-face) or an online platform (zoom meeting software). Phase 2 involved determining the students' responses. A questionnaire was distributed amongst the participants after the lecture and collected for analysis. Fisher's exact test was used to analyze the data statistically, and the significance level was set at 0.05 (p < 0.05). RESULTS: A total of 1082 participants were involved in this survey. Overall, 93% of study participants found that Ahmed et al. classification system was more practical and accurate than Vertucci et al. system and its supplemental configurations (p < 0.001). About 97% agreed that Ahmed et al. classification system aided in understanding root and canal morphology better than Vertucci's and its additional configurations, and they recommended to include in their curriculum (p < 0.001). CONCLUSIONS: In comparison to Vertucci's classification system and supplementary types, the undergraduate and postgraduate dental students, and interns in India agreed that Ahmed et al. classification system is more practical and accurate for classifying the root and canal morphology.

Validity and reliability of palatal rugae morphometric assessment with 3D laser scanned models

Aim: To assess the reliability and validity of morphometric features on 3D digital models produced by scanning maxillary dental casts of Malaysian Malay subjects. Methods: Dental casts of 20 subjects were scanned using a 3D laser scanner (Next Engine Inc., Santa Monica, California, USA). The palatal rugae morphometric features were assessed on the resulting 3D models using 3-Matic Research 9.0 software (Materialise NV, Heverlee, Belgium). The assessments were repeated by the first and second authors to assess the intra- and interexaminer reliability, respectively. Rugae morphometric features were also evaluated on the conventional plaster models to assess the validity of the 3D method. Results: Kappa values of the validity ranged from 0.807 to 0.922 for rugae shape, size category and direction. The intraclass correlation coefficient (ICC) for rugae number validity was 0.979. For intra-examiner reliability, kappa values ranged from 0.716-1.000 for rugae shape, size category and direction. The ICC for rugae number intra-examiner reliability was 0.949. Kappa values of interexaminer reliability for rugae shape, size category and direction were 0.723-885, while the ICC of rugae number was 0.896. Conclusion: Palatal rugae analyses on 3D digital models scanned by the 3D Next Engine laser scanner using 3-Matic Research 9.0 software are valid and reliable