Evaluation of the performance of premolar and second molar maturity indices in estimating age 12

Objective: Age determination plays a crucial role in defining the legal and social rights of children. In many countries, the minimum age of criminal responsibility is set at 12 years. This study aimed to determine cut-off values to distinguish the 12-year age threshold using the first premolar maturity index (IPM1), second premolar maturity index (IPM2), second molar maturity index (I2M), and the sum of the seven mandibular teeth indices (S value) in a Turkish population. Additionally, the diagnostic performance of these cut-off values was evaluated. Method: In this retrospective study, a total of 1136 orthopantomographs of individuals aged 8-16 years were analysed. The sample was randomly divided into two groups as training and validation group. In the training group, IPM1, IPM2, I2M and S value were measured and cut-off values were determined for 12 age limits. In the validation group, receiver operating characteristic (ROC) curves were generated for these cut-off values and the area under the curve (AUC) was calculated. Interobserver and intraobserver agreement was assessed with the intraclass correlation coefficient. Results: The optimal cut-off values were determined to be 0,014 for IPM1, 0,069 for IPM2, 0,184 for I2M, and 0,350 for the S value in females; and 0,030 for IPM1, 0,090 for IPM2, 0,191 for I2M, and 0,412 for the S value in males. The highest AUC values for the male group were calculated as 0,966 for I2M in univariate methods and 0,969 for I2M+IPM1 in bivariate methods. For the female group, the highest AUC values were calculated as 0,950 for IPM2 in univariate methods and 0,950 for IPM1+IPM2 in bivariate methods. In the method containing the S value, the AUC values were calculated as 0,951 and 0,970 for females and males, respectively. Conclusion: IPM1, IPM2, I2M, and the S value showed high diagnostic performance for the 12-year age threshold in Turkish children. There was no significant difference between the methods in terms of AUC in females, whereas a significant difference was observed only for the IPM2 method in males. Key words: forensic age estimation, legal age threshold, maturity index, ROC analysis