Evaluation of the validity of Demirjian and Nolla methods in estimating chronological age in an Iranian population

Abstract

<h3>Objective</h3> Due to demographic and ethnic-racial differences, each dental age estimation method should be examined in a limited population to evaluate the accuracy of the selected method. Therefore, this study aimed to evaluate the validity of Demirjian and Nolla methods in estimating the chronological age of an Iranian population of children aged 7 to 15 years in Tehran. <h3>Study Design</h3> This retrospective cross-sectional study was performed on 301 panoramic radiographs of children in the Radiology Department of the Shahid Beheshti University of Medical Sciences, School of Dentistry. Dental age was calculated by evaluating the seven left mandibular teeth using Demirjian and Nolla methodologies. Data were analyzed by using the Wilcoxon signed rank test and the intraclass correlation coefficient. <h3>Results</h3> By the Demirjian method, the mean differences between dental and chronological ages for girls, boys, and all samples were 1.784 ± 0.042, 1.704 ± 0.207, and 1.720 ± 0.024, respectively. Using Nolla's method, the mean difference between dental and chronological age for girls, boys, and all samples were -1.432 ± 1.742, -1.386 ± 1.87, and -1.492 ± 1.567 respectively. Intraclass correlation coefficients for the Demirjian and Nolla methods were 77% and 71%, respectively. <h3>Conclusion</h3> The Demirjian method is more accurate compared to the Nolla method for estimating age in the population of Iranian children in Tehran. <b>Statement of Ethical Review</b> Ethical review was sought and study was exempted from ethical review