Validity of Willems Method Based on Molar and Premolar Development in in 3-18 year old Individuals in the City of Isfahan

The accuracy of Willems and Demirjian’s methods can be affected by different patterns of calcifications of molars and premolars. In this descriptive-cross sectional study, 152 panoramic radiographs of 47 boys and 105 girls aged 3 to 18 were used. The dental age of samples was determined by Willems and Demirjian’s methods. Based on the developmental of first and second premolars and second molar the following ranking was made: 1. The development stage of the first premolar and the second premolar is the same. 2. The development stage of the first premolar is earlier than the second premolar. 3. The development stage of the second premolar and the second molar is the same. 4. The development stage of the second premolar is earlier than the second molar. Data were entered into SPSS 17 software and analysed by paired t-test. Demirjianʼs method overestimated the age of the teeth (0.5 years) and Willmsʼ method under estimated the age of the teeth (0.2 years) that shows the higher accuracy of the Wilelmsʼ method. The Willems method in the first group of the whole population,in the girls of the first group and in the boys of the second group showed the highest accuracy. Demirjian’s method in the whole population and in the girls of the second group and in the boys of the third group showed the highest accuracy. This research showed that the accuracy of Willemʼs method is higher than Demirjianʼs, and different patterns of tooth development affect the accuracy of these methods and will help the forensic dentist to be more ensured.