Application Of Three Methods Of Dental Age Estimation In Mongolian And Han Adolescents In Hohhot Area

Objective Demirjian,Willems and Haavikko dental age estimation methods were used to evaluate the accuracy of the three methods in inferring the dental age of Mongolian and Han people aged 8-15 in Hohhot.In order to better judge the growth and development of Mongolian and Han adolescents in Hohhot,and provide a basis for oral clinicians to formulate better treatment plans.Methods A total of 632 panoramic radiographs were collected from people aged 8to 15 who were treated at the Oral Imaging Center of Affiliated Hospital of Inner Mongolia Medical University and the Imaging Center of Hohhot Stomatological Hospital from January 2019 to December 2021.There were 322 cases of Han nationality(159 males and 163 females)and 310 cases of Mongolian nationality(155males and 155 females).Demirjian method,Willems method and Haavikko method were used to observe the whole panoramic radiographs.The tooth development stages of seven permanent teeth from 31(lower left central incisor)to 37(lower left second molars)were recorded,and convert them according to the dental age conversion table,and then get the dental age.SPSS 20.0 software was used for statistical analysis.The measurement data were statistically described by(`X±S),the normality test was performed by single-sample K-S test.The comparison between dental age and chronological age adopts paired sample T test to compare the difference between dental age and chronological age,and the Absolute mean error(MAE)between dental age and chronological age was compared to explore its accuracy.Through correlation analysis,scatter diagram was constructed,regression equation was obtained by linear fitting combination,and Willems method was modified.Statistical analysis was performed by two-sided test,assuming that levelα=0.05,P>0.05,the difference was not statistically significant.Results 1.In this study,Demirjian method was used to evaluate the dental age of Han adolescents.The average overestimation of males was 1.05 years(P<0.05),and the average overestimation of females was 0.98 years(P<0.05).The MAE were 1.07years and 1.16 years,respectively.When evaluating the dental age of Mongolian adolescents,the average overestimation was 0.94 years in males(P<0.05)and 0.89years in females(P<0.05),and the MAE were 0.97 years and 1.05 years,respectively.2.In this study,Willems method was used to evaluate the dental age of Han adolescents.The average overestimation of males was 0.41 years(P<0.05),and the average overestimation of females was 0.29 years(P<0.05).The MAE were 0.63years and 0.75 years,respectively.When evaluating the dental age of Mongolian adolescents,the average overestimation was 0.36 years in males(P<0.05)and 0.29years in females(P<0.05),and the MAE were 0.63 years and 0.63 years,respectively.3.In this study,Haavikko method was used to evaluate the dental age of Han adolescents.The average underestimation of males was 0.88 years(P<0.05),and the average underestimation of females was 0.96 years(P<0.05).The MAE were 1.07years and 1.15 years,respectively.When evaluating the dental age of Mongolian adolescents,the average underestimation was 0.72 years in males(P<0.05)and 1.01years in females(P<0.05),and the MAE were 0.98 years and 1.17 years,respectively.4.In this study,the difference between the dental age obtained by the three dental estimation methods and the chronological age was statistically significant(P<0.05).The regression equation between the chronological age(Y)and the dental age(X)of Han adolescents is Y=1.010*X-0.5273(male),R~2=0.91,Y=1.046*X-0.8467(female),R~2=0.84.The regression equation between the chronological age(Y)and the dental age(X)of Mongolian adolescents is Y=0.9767*X-0.07877(male),R~2=0.89,Y=0.9624*X+0.1715(female),R~2=0.90.There was no significant difference between the dental age obtained by the modified Willems method and the chronological age(P>0.05).Conclusion 1.Demirjian method,Willems method and Haavikko method were used to estimate the dental age of the Mongolian and Han people in Hohhot area aged8-15 years,and the difference was statistically significant(P<0.05),indicating that the three dental age estimation methods have different degrees of difference.Cannot be used directly for the estimation of dental age.2.Compared with the three methods,Willems method has the lowest MAE,indicating that the difference of Willems method is smaller than the other two methods,and the accuracy is improved compared with the other two methods.3.The modified dental age regression equation was used to estimate the dental age of the Mongolian and Han populations aged 8-15 years old in Hohhot area,and the difference was not statistically significant(P>0.05),which indicated that the modified revised regression equation estimated the dental age with high accuracy and could be directly used to infer the dental age.