Age Estimation Using the Demirjian and Willems Methods in a Southern Thai Population

Abstract

The objective of this study was to test the accuracies of the Demirjian and the Willems dental age estimation methods using the seven left permanent mandibular teeth (excluding the third molar tooth) in children in southern Thailand. Digital panoramic radiographs of 240 Thai children (120 males and 120 females) aged from 8 to 15 years were chosen and separated into eight age groups. Dental age was assessed using the Demirjian and the Willems methods. Differences between the dental age and the chronological age were statistically evaluated by the Wilcoxon signed-rank test. The results showed that the Demirjian method overestimated age by 0.28 years and 0.24 years for males and females, respectively, while the Willems method underestimated age by −0.04 years and −0.23 years for males and females, respectively. Moreover, the mean absolute errors were 0.68 years in males and 0.56 years in females for the Demirjian method and 0.55 years in males and 0.60 years in females for the Willems method. In conclusion, the Willems method was more accurate for dental age estimation compared to the Demirjian method. However, both methods can be applied to estimate the age of children in southern Thailand since the mean error and mean absolute error values were less than one year. Keywords: Dental age estimation, Demirjian method, Tooth developmental stage, Thai population, Willems method