Discrepancies and associations among chronological age, dental age, and cervical vertebral maturation in growing orthodontic patients: a cross-sectional study in a Spanish orthodontic clinical sample

Background: Biological maturation varies substantially among children of the same chronological age, which may affect growth-based orthodontic decisions. Methods: In this cross-sectional study, 120 patients aged 8 to 16 years were evaluated using routine or- thodontic diagnostic records. Chronological age was compared with dental age estimated using the Nolla and Demirjian methods, and skeletal maturation was assessed using cervical vertebral maturation stages (CVMS). Associations with sex, BMI, BMI-for-age z-score, and menarcheal status in females were exam- ined. Results: Both dental methods systematically overestimated chronological age. Mean discrepancies were + 0.59 years for the Nolla method (95% CI: 0.39-0.79; Cohen's dz = 0.52) and + 1.09 years for the Demir- jian method (95% CI: 0.87-1.31; Cohen's dz = 0.89) (both P < 0.001). Female participants exhibited a higher proportion of pubertal and postpubertal CVMS than males (Cramer's V = 0.41; P < 0.001), although sex differences in dental age discrepancies were small (Cohen's d ≤0.14). BMI and BMI-for-age z-scores were positively correlated with dental age discrepancies ( ρ= 0.27-0.31) and CVMS stage ( ρ= 0.35-0.36) (all P ≤0.003), indicating small-to-moderate associations. Menarcheal status was not significantly associ- ated with CVMS ( P = 0.727) or dental age discrepancies ( P > 0.05). Conclusions: Chronological age alone provides an incomplete estimate of biological maturation. Dental age estimation and CVM assessment offer com plementary but nonequivalent information, and their interpre- tation should consider sex and basic anthropometric context.