Measurement of the open apices of mandibular first and second premolars to test the chronological age over 14 years: Study on a sample of south Indian children

Age estimation is an integral part of forensic medical and dental practice. In many countries, the age threshold of 14 years is set to determine the minimum age for criminal responsibility. In the present study, the authors studied the final maturation of the first (IPM1) and second mandibular premolars (IPM2) by Cameriere maturity index and determined cut-offs at the age threshold of 14 years, and validate on the test sample. Orthopantomograms of 960 healthy south Indian children and sub-adults (480 boys and 480 girls) aged between 10 and 18 were analysed, 640 as training sample and 320 as a test sample. The results of logistic regression analysis with age (</>= 14 years) as a dependent variable and IPM1, IPM2, and sex as predictor variables on training sample showed that both IPM1 and IPM2 significantly related to the legal age of 14 years but not the sex (p = 0.052). A receiver operating characteristic (ROC) curve analysis was performed to evaluate the specific cut-off values of IPM1 and IPM2 for predicting 14 years. A cut- off value of IPM1 < 0.01 and IPM2 < 0.02 were obtained using the highest Youden index value. Our results on test sample showed that the combined predictor, IPM1 + IPM2 < 0.02, showed the highest specificity (97.5% in boys and 92.5% for girls), better post-test probability, 97.2% in boys and 91.9% for girls, and a smaller number of false positives (6.8%). In conclusion, the combination of IPM1 and IPM2 could be useful in determining the age of over 14 years in south Indian children.