Purpose: To compare the applicability and validity of dental age (DA) estimated by Willems method and cervical vertebral bone age (CVBA) evaluated by regression formula in estimating the chronological age of children in Shanghai.
Methods: Panoramic radiographs and lateral cephalograms were retrospectively collected from 320 subjects (160 males, 160 females), totaling 640 images. Discrepancies between chronological and estimated ages were statistically calculated by paired samples t test or Wilcoxon signed rank test using SPSS 25.0 software package. The accuracy of the two methods was comprehensively evaluated by comparing their standard deviation, mean absolute error (MAE) and the correct rate of acceptable range of estimated age error.
Results: The mean DA underestimated CA by 0.75±1.03 years for males and by 1.05±1.18 years for females; whereas the mean CVBA underestimated CA by 0.78±1.40 years for males and 0.53±1.31 years for females. MAE of Willems method was 1.15 years and the MAE of regression formula of CVBA was 1.20 years. The correct rate of clinically acceptable error of 0.5 years was 26.25% for Willems method and 27.19% for regression formula of CVBA.
Conclusions: Willems method is more accurate than regression formula in indicating cervical vertebral skeletal age of adolescents in Shanghai children. Because of significant differences between CA and estimated ages, further modifications are urged to improve the accuracy of these two methods.