# Geometric Morphometric Shape Analysis of Mandibular Post-Canine Dentition
## 4 Discussion  
Tooth morphology is a fascinating and complex subject that is essential for dental professionals to understand. By analyzing the landmarks of dental anatomy, we can gain a better understanding of tooth morphology and improve treatment outcomes. The shape variation in teeth also correlates with ancestry, making it an important area of study for dental professionals. With a thorough understanding of the shape variation in and cusp configuration of the mandibular post-canine dentition, dental professionals can contribute to various fields of work. The present study aims to investigate the shape variations in mandibular premolars and molars, which are crucial for dental treatments such as orthodontics, restorative dentistry, and prosthodontics. Furthermore, documenting population-specific morphological alterations can serve as a reliable indicator of ancestry, providing valuable information for forensic investigations and anthropological studies. This information can help dental professionals identify individuals and provide insight into their ancestry, which can be useful in a variety of settings. In our study, we observed that the mandibular molars and the two-cusp-type mandibular second premolars displayed dimorphism. This means that there were noticeable differences in the size, shape, and structure of these teeth between males and females. It is possible that sex-linked genes influence enamel and dentin contributions to crown size. [PERSON] and [PERSON] (2005) reported that males and females have similar amounts of enamel. However, males have a significantly higher proportion of dentin in the lower molars [10]. The study of individuals with aneuploid sex chromosomes has shown that the X chromosome is associated with enamel thickness, and the Y chromosome is associated with both enamel and dentin thickness [18,19]. The role of hormones in contributing to dimorphism is less likely for the mandibular first and second molars. This is because the crown of the mandibular first molar is completed by the age of 2-3 years, while the crown of the mandibular second molar is completed by the age of 7-8 years. The growth spurt only occurs during the ages of 12-15 years, when the third molar is forming. Therefore, dimorphism associated with  
Figure 4: Line graphs depicting landmark changes between sexes in the mandibular first and second molars Note:dark blue represents female and light blue represents male and the numbers represent the landmarks. -hormonal influence is more likely for the third molar, but not the teeth mesial to it [10; 20]. In a recent study, conducted by [PERSON] et al. (2020), the shape of the enamel-dentinal junction (EDJ)) was examined and found to have a significant correlation with genetic drift, rather than adaptive processes, as seen in bone shape. The researchers also emphasized that the shape of the EDJ is a heritable factor, indicating that genetics play a larger role in tooth shape than hormones, habits, or other external factors [21]. [PERSON] et al. (2007) conducted a morphometric analysis of mandibular premolars and discovered that female teeth had a significantly higher proportion of enamel formed in the cusp area. Specifically, they found that the average enamel cap area was 11.8% greater in females than in males [22]. Our study builds upon this research by revealing that female cusps are positioned higher and have sharper configurations [10]. Further investigation is needed to explore the relationship between the X chromosome and the higher quantity of enamel formation observed in females. In our study, we observed that the occlusal table of the mandibular first molar was narrower in females. This finding is consistent with the study conducted by [PERSON] et al. (2014), who reported that the occlusal table area was significantly smaller in females (44.92 mm\({}^{2}\)) compared to males (49.90 mm\({}^{2}\)).