Chronology of third molar mineralization in a northern Chinese population

Dental age estimation is of great importance for individual identification in forensic medicine and many other fields. The present study aimed to provide reference data for chronological aging based on mineralization of third molars in a northern Chinese population. A total of 3212 digital orthopantomograms from 1551 males and 1661 females of northern Chinese origin ranging in age from 5 to 25 years were assessed. The mineralization status of the third molars was assessed using the formation stages described by Demirjian et al. with two modifications. Results showed that left and right third molars were generally at similar stages of mineralization. The third molars 18 at stage D, 28 at stage D, 38 at stage D and 48 at stages B and G showed significantly lower mean ages in males than in females. In comparison to different ethnic groups there were some significant differences in the chronological course of third molar mineralization. As possible causes of these differences, ancestry, socioeconomic status, eating habits and statistical phenomena, such as age range and age distribution of samples are discussed.