Dental age assessment in 7-14-year-old Chinese children: comparison of Demirjian and Willems methods.

Several approaches have proven be valuable in estimating dental age in children. The Demirjian method, based on crown and root calcification, is the most frequently used tool. The Willems method is a modification of the Demirjian method. There are few studies regarding to compare the application of the two methods in China. This study aims to apply the two methods in a Han population as well as identify if there are some differences between two methods in estimating dental age versus chronological age. Nine hundred forty-one orthopantomograms of 410 boys and 531 girls between seven and 14 years of age were selected from our patient records database with defined standard, and the Demirjian and Willems methods of dental age estimation were applied. The seven left mandibular teeth were scored and calculated in order to obtain the Demirjian and Willems estimated dental ages. It is suggested that the Demirjian method overestimated chronological age by 1.68 years for boys and 1.28 years for girls. The discrepancy between the Demirjian estimate and the chronological age was most frequently observed between 1 and 3.5 years for boys and between 1 and 2 years for girls. While it is indicted that the Willems method overestimated chronological age by 0.35 years for boys and underestimated the age by 0.02 years for girls. The discrepancy between chronological age and Willems estimated age was most frequently observed between -0.5 and 0.5 years for boys and between -1 and 0.5 years for girls. It is demonstrated that the Willems method was more accurate in estimating dental age than the Demirjian method, with a mean absolute error of 0.98 years for boys and 0.93 years for girls. As a result, it is highly recommended that the Willems method should be applied when estimating dental age in Chinese Han population, further modifications to the method are suggested.