Background: Dental estimation is important in identification processes, and its application to estimate Chronological Age (CA) in living minors for whom a date of birth is not available. This study compares two methods to estimate dental age based on dental development in a sample of Mexican children. Methods: A cross-sectional, retrospective study was performed on 568 orthopantomographs corresponding to Mexican children (268 boys and 300 girls) aged 4 to 15 years old of either sex, who met the inclusion criteria. Maturation stages were assigned based on Demirjian and Nolla methodologies. We obtained CA from records and measured accuracy in the Mexican sample using each method. The mean age and standard deviations (±SD) were calculated by age and sex. Data was analyzed using Kolmogorov-Smirnov, Shapiro-Wilk (p < 0.001), Kruskal-Wallis H, Wilcoxon tests and Spearman’s correlation coefficient between CA and Dental Age (DA). Results: DA obtained by Demirjian method was 10.9 ± 2.9 years, and DA calculated by Nolla was 9.7 ± 3.2 years. The total sample presented DA overestimation with Demirjian method of −0.8 ± 1.4, with significant differences between CA and DA (p < 0.001). DA underestimation with Nolla method of 0.4 ± 1.5, with significant differences between CA and DA (p < 0.001). DA did not differ significantly between the sexes using either method (p > 0.05). Conclusions: Both methods estimated CA and DA as correlated. Pediatric dentistry plays a crucial role in determining whether a patient’s dental maturation is within the average for their age group. In forensic science, however, the methods must provide an estimated age as close to the real age, as the civil or criminal treatment of the individual depends on it.