Aim: This study evaluated the relationship between age, sex, and mandibular morphological changes, focusing particularly on mandibular cortical width (MCW) and mandibular cortical index (MCI), using panoramic radiography. Methods: A total of 300 panoramic radiographs were analyzed. Mandibular morphometric parameters were measured, including ramus height, maximum and minimum ramus width, gonial angle, bigonial width, condylar height, coronoid height, MCW, and MCI. Statistical analysis included Spearman's correlation, multiple regression, and logistic regression to assess the relationships between mandibular morphology, cortical width, and cortical erosion with age and sex. Results: Significant differences were observed across age and sex groups in most mandibular parameters. Men had significantly larger values for ramus height, bigonial width, and condylar height, while women showed a wider gonial angle. Age was negatively correlated with MCW (r = −0.522, p = 0.000) and positively correlated with MCI (r = 0.388, p = 0.000), indicating that cortical width decreases and cortical erosion increases with age. In the multiple regression analysis, age (B = −0.028, p = 0.000) and MCI (B = −0.391, p = 0.000) were strong negative predictors of MCW. In contrast, condylar height (B = 0.024, p = 0.007) positively influenced MCW, explaining 41.5% of the variance in cortical width (R² = 0.415). The logistic regression analysis revealed that MCW [Exp(B) = 0.157, p = 0.000], sex [Exp(B) = 2.251, p = 0.005], and age [Exp(B) = 1.062, p = 0.000] significantly predicted MCI, with thinner mandibular cortices, female sex, and older age associated with higher MCI values (severe cortical erosion). Each 1 mm decrease in MCW increased the likelihood of being in a higher MCI class by 84%. Conclusions: Women were more than twice as likely to exhibit greater cortical erosion than men. This study demonstrated that age, sex, and mandibular morphometric parameters significantly influenced MCW and erosion. 2025 Kiswanjaya, Taufiq, Syahraini and Yoshihara.