Applicability and accuracy of Demirjian and Willems methods in a population of Eastern Chinese subadults.

Background: To assess the validity of the Demirjian and Willems dental age estimation methods in a population of Eastern Chinese 11-18-year-old subadults.

Samples And Methods: A total of 1622 orthopantomograms (787 boys and 835 girls) aged from 11.00 to 18.99 years old from a Chinese Han population were evaluated in the study. Dental ages were calculated using both Demirjian and Willems method. Statistical significance was set at p<0.05 and for each method, discrepancies between chronological age (CA) and dental age (DA) were statistically analyzed by paired t-tests. Special age interval analysis was conducted by Chi-square tests to compare the accuracy of the Demirjian and the Willems methods.

Results: Demirjian method underestimated CA 0.66±1.45 y (p<0.001) in boys and 0.62±1.61 y (p<0.001) in girls while Willems method underestimated 0.90±1.32 y (p<0.001) and 0.97±1.56 y (p<0.001) in boys and girls, respectively. The mean absolute error (MAE) value between the CA and the DA (CA-DA) using the Demirjian method and the Willems method were 1.31 and 1.29 y for boys, respectively, and 1.35 and 1.43 y for girls, respectively.

Conclusions: It is suggested that the Demirjian method was found to be more accurate compared with the Willems method. However, the Demirjian method may not be satisfactory for 11-18-year-old children of Eastern China. It is recommended that a modified Demirjian method for better dental age estimation for Eastern Chinese juvenile individuals.