DENTAL AGE ESTIMATION BY DEMIRJIAN'S AND NOLLA'S METHOD: A COMPARATIVE STUDY AMONG CHILDREN OF MONTEVIDEO, URUGUAY

Objectives: To compare the accuracy of estimating chronological age (CA) from dental age (DA) measured with the Nolla and Demirjian methods in a children population of Montevideo, Uruguay.
Methods: An observational analytical study was performed on a sample of 667 panoramic radiographs taken from children who ranged in age from 4 to 16 years, and who met the inclusion criteria (healthy patients without dental treatment in the lower left quadrant). The mean and standard deviation CA of the study sample was 10.26 years ±2.93 (366 women, 301 men). Two observers conducted the measurements and were calibrated for assessment of inter and intra class correlation for both methods (ICC: Intra-observer Nolla’s 0.98-0.98; Demirjian’s 0.98-0.99. Inter-observer Nolla 0.97, Demirjian 0.96). The relationship between chronological and dental age was evaluated by each method, gender and age groups, as well as in the total population. Kolmogorov-Smirnov and Shapiro Wilk tests were performed to assess the normality of the data and, as a result, the DA and CA were compared using the Wilcoxon Signed Rank test (p≤0. 05). Regression methods were applied to model CA as a function of DA.


Results: The Kolmogorov-Smirnov test rejected normality for each age group. The Demirjian’s method yielded a significant difference between DA and CA (0.98 years, p<0.0001), while the difference between Nolla’s DA and CA was not significant (0.10 years, p=0.5305). Regression equations forecasting chronological age by method, age, and gender are presented.
Conclusions: Dermirjian’s method overestimated CA by about one year, while Nolla’s overestimated by just 0.10 years according to the study sample used. For this population of children form Montevideo-Uruguay, Nolla’s method was more accurate to estimate CA than Demirjian’s.