comparison of demirjian and willems methods in estimating dental age and modification of willems method for 7 - 15 year olds iranian population

Background: age estimation is of great importance in many medical fields and dentistry. it is also extensively used in archeology, criminology, and forensic medicine. considering the importance of dental age estimation, this study was designed. objectives: this study aimed to evaluate the accuracy of demirjian and willems methods for estimating the dental age of 7 - 15-yearolds population of the north of iran. we also modified the willems method for this population and compared the results of the modified and original willems methods. methods: in this cross-sectional, descriptive, analytical study, a total of 1320 panoramic radiographs in the age range of 7 - 15 years, were examined. dental age was determined by the demirjian and willems methods and compared with the chronological age. next, a formula based on the willems method was formulated. finally, the results of the modified and original willems methods were compared. results: the demirjian method overestimated the chronological age by 0.49 years (0.57 for girls and 0.36 for boys), and the willems method overestimated this age by 0.07 years (0.03 for girls and 0.14 for boys), too. the mean error of the modified willems method waszero for the total sample, although formostage subgroups, themodifiedmethodwasmoreerroneous than the original method. demirjian method had larger overestimations for girls than for boys, whereas the opposite was found for the willems method. conclusions: the demirjian and willems methods both overestimated the chronological age. however, the overestimations were smaller in the willems method. based on the findings, the original willems method was the preferred choice for age estimation.