Accuracy of Demirjian’s Method to Estimate Chronological Age in 5‒17-Year-Old Iranian Population

Introduction: To detect physiological maturity of a child, use of dental and skeletal development can be helpful. The Demirjian’s Method is one of the commonly used methods to estimate dental age. The aim of the present study was to evaluate the validity of Demirjian method in Iranian population with different races.

Materials and Methods: The present cross-sectional study was performed on a randomly selected sample of panoramic radiographs of 3073 patients aged 5‒17 years. The chronological age (CA) was calculated by subtracting the date of birth from the date on which the radiographs were taken. Estimated age (EA) was performed by Demirjian method using seven left mandibular teeth. Paired t-test was used to compare differences between chronological and estimated age.

Results: The mean of CA was 11.14±2.61 years whereas the mean EA was 11.35±2.62; therefore, EA was calculated 2.5 months more than CA. According to paired t-test the difference between CA & EA was significant (P≤ 0.001). Pearson’s correlation coefficient showed a strong linear correlation between CA and EA in total (r=0.891, P≤0.001), in girls (r=0.895, P≤ 0.001) and in boys (r=0.876, P≤ 0.001). The new regression line equation based on Iranian standards would be CA=1.08±0.89EA in total, CA=1.09±0.89EA in girls and CA=1.12+0.88EA in boys.

Conclusion: Using Demirjian’s Method overestimated dental age in the Iranian population. A new regression line equation based on Iranian standards was obtained according to the results of the present study.