Background <p>Accurate age estimation is essential in forensic and clinical contexts, particularly where birth records are unavailable. Dental development assessed through radiographic calcification is considered a reliable indicator. However, atlas-based methods have demonstrated variable accuracy across populations. This study aimed to evaluate the accuracy and agreement of the Schour and Massler chart and the London Atlas, and to develop a population-specific dental development scheme for a Pakistani cohort.</p> Methods <p>A cross-sectional forensic validation study was conducted using 700 digital panoramic radiographs of individuals aged 4.0–17.9 years, stratified by age and sex. Dental age was estimated using both methods and compared with the chronological age. The analyses included paired t-tests, correlation, intraclass correlation coefficient, Bland–Altman analysis, and linear regression. The predictive performance was assessed using the mean absolute error and proportions within ± 1 and ± 2 years.</p> Results <p>Both methods demonstrated strong correlations (<i>r</i> &gt; 0.90) and high ICCs (&gt; 0.85). The London Atlas showed lower mean bias (~ 0.2–0.4 years), narrower limits of agreement (± 1.5–2.0 years), and higher predictive accuracy (overall R² = 0.997; sex-stratified subgroup range: R² = 0.92–0.95) than the Schour and Massler method (overall R² = 0.982; sex-stratified subgroup range: R² = 0.85–0.90). Accuracy within ± 1 year was higher for the London Atlas (&gt; 75%) compared with Schour and Massler (&lt; 65%), while both exceeded 90% within ± 2 years. Population-specific analyses revealed a delay in early dental development.</p> Conclusions <p>The London Atlas demonstrated superior agreement and predictive performance; however, population-specific variations limit its universal applicability. The newly developed Pak Atlas provides a more accurate reference for forensic age estimation in the Pakistani population, with direct relevance to medico-legal age assessment.</p>