Validity of Demirjian 8-teeth method for age estimation by orthopantomogram – A prospective study

Abstract

Background: Demirjian et al. (1973) put forth a method of age prediction, which used seven mandibular teeth on the left side. The technique has been widely applied but revealed variations in age estimates in other populations, including Indians. The aims and objectives of our study were to validate the Demirjian 8-teeth method using orthopantomogram to estimate the reliability of age estimation after incorporating the third molar and to predict the accuracy of age estimation using Indian-specific formulae. Materials and Methods: The study was conducted on the local population with 49 subjects (mean = 18, f = 31) less than 18 years of age. The soft copies of the radiographs of selected subjects were retrieved from the computer attached to the digital orthopantomogram machine (Orthophos XG5; Sirona Dental Systems). Staging of each tooth of left mandibular side was done using Demirjian 8-teeth method. Dental age was calculated using the modified formula given by Acharya et al. and statistical methods were used to compare it with chronological age. Results: The overall mean absolute error (MAE) of the 49 subjects was 0.911 ± 1.65. The highest MAE was in the 13-year age group (1.82 years) while it was lowest in the 18-year age group (0.43 ± 1.10 years). In all, 15 subjects (30.6%) had an error in age estimation which is less than 1 year and 12 subjects (24.5%) had an error of more than 2 years The accuracy of age estimation was found to be better in 16–18 years age group as compared to younger age group, probably because of better development of the third molar by this age. Conclusion: The reasonably good results obtained in this study assert the use of Demirjian's 8-teeth method with Indian cubic functions in the local population.