Background: Multiple teeth in varied stage of dental development provide sufficient data source for accurate age estimation, but only till the age of 14 years. The difficulty in human age estimation after 14 years of age has greatly shifted the focus on third molar which offers a unique advantage over other teeth because its development tends to continue over a longer period and until a later age. Aim: Aim of this study was to estimate the age of adolescents and young adults based on Demirjian’s method for the development of mandibular 3rd molars using panoramic radiographs. Material and Methods: The retrospective study was carried out on 150 digital orthopantomograms of patients in the age group of 13­23 years obtained from the archives at our institution, MP dental college, Vadodara, Gujarat. Demirjian’s tooth development method was used. Mandibular right third molar was used, if missing, contralateral molar was used. Data was analysed by using SPSS software (STAT IC­13). Results: The linear regression formula was applied which revealed age predilection with mean error of 1.83 year in which 60% cases were estimated within 1 year of actual age, while 40% cases were estimated to be >±1 years from actual age. There was a significant correlation between dental age and chronological age. The predicted age for male was 18.56 ± 1.69 and for female were 18.64 ± 2.21. Conclusion: Assessment of third molar using Demirjian’s method can be used in estimating age for medico­legal purposes. As the Demirjian’s method was based on French population, derivation of population specific formula is recommended. 

Keywords: Age Estimation; Demirjian’s Method; Third Molar; Dental Radiography; Population Specific Formula.