The time frame of third molar mineralization in a northern chinese population

A key criterion in dental age determination is the assessment of third molar mineralization. The objective of this study was to provide reference data for Demirjian stages D-H of teeth 38 and 48 in a northern Chinese population. To this end, 988 digital orthopantomograms (OPGs) of northern Chinese individuals aged 12-26 years were examined. Of the total sample, 822 OPGs showed at least one evaluable lower third molar. The mean ages for both teeth in males are above 18 years from stage G onwards. In females, the mean ages for both teeth are above 18 years from stage F onwards. The youngest individuals with mineralization stage H were older than 18.0 years in both sexes. Since studies with larger case numbers have also reported minimum ages for this stage below the age of 18, the minimum ages for stage H presented in this study cannot be recommended for age assessment practice. In order to avoid stage misclassifications, which are particularly problematic when applying the minimum age principle, stage classifications in future studies should be made consensually by experienced examiners.