Comparison Study Between Two Different Methods Of Dental Age Estimation In Shanghai Adolescents

Purpose:(1)To evaluate the applicability of Demirjian and Willems methods of dental age estimation for Shanghai adolescents.(2)The accuracy between the Demirjian and Willems methods was compared to MAE for the chronological age and dental age.Method:(1)1604 Digital panoramic radiographs(individuals aged between 11 to 18 years.)were selected who from January 2014 to July 2016 visited Oral and Maxillofacial Radiology Department of the Ninth People's Hospital Affriliated with Shanghai Jiaotong University School of Medicine(820 panoramic radiographs for males and 877 panoramic radiographs for females).(2)The panoramic radiographs were used to evaluate the maturity score of the seven left mandibular teeth.Dental age was assessed by using Demirjian and Wilems methods.The discrepancies between chronological ages and dental ages were statistically analyzed by the paired t-test and Wilcoxon Signed rank test.(3)The mean absolute error(MAE)between chronological age and dental age was compared to evaluate the accuracy between the Demirjian method and Willems methds.Results:(1)Compare the Demirjian chronological ages and dental ages for males and females.For males,the overestimation of age was seen in 11 to 15 year age group,and the underestimation was seen in 16 to 18 year of age group;compare the Willems method chronological ages and dental ages for males and females,the underestimation of age was seen in all age groups for males,the overestimation of age was seen in 11 to 14 year of age group and the underestimation of age in 15 to 18 year of age group by females.(2)The mean age difference between chronological age and dental age was 0.37 years(SD1.40)(P<0.01)for males,0.14 years(SD 1.61)(P<0.05)for females,and 0.24 years(SD 1.52)for entire sample according to Demirjian method.The mean age difference was 0.66 years(SD 1.28)(P<0.01)for males,1.31years(SD 1.50)(P<0.01)for females and 0.62 years(SD 1.40)for entire sample according to Willems method.In conclusion,Both Demirjian and Willems method were showed significant differences between the chronological age and dental age..(3)Compare the MAE betwen Demirjian method and.The MAE was 1.28 years in entire sample according to Demirjian method and 1.26 years according to Willems method.The Willems method was more accurate than the Demirjian method for males with a lower MAE.Conclusion:(1)The Demirjian method underestimated age by 0.37 years for males,0.14 years for females;while the Willems method underestimated age by 0.66 years for males and 1.31 years for females.(2)The Demirjian method may not be suitable for estimating the dental age for Shanghai adolescents.It should be modified before use.(3)The Willems method is more accurate than Demirjian method in entire sample with a lower MAE.The males were more accurate in both methods.