Correlation of chronological, skeletal and dental (Demirjian method) ages in an Iranian growing orthodontic population – a cross-sectional study

Growth modification treatments are a type of orthodontic treatment used for patients who are still growing. The treatment plan and timing for these interventions are generally based on the chronological age of patients; however, achieving the most desirable outcome requires a thorough understanding of the physical development of children and adolescents. The aim of this study is to examine the correlation between chronological age and physical development in children and adolescents requiring orthodontic treatment. To assess physical development, both dental age and skeletal age were evaluated. Panoramic and lateral cephalometric radiographs of 194 orthodontic patients aged 7 to 17 years were randomly selected from a dental clinic in Gachsaran. Dental maturity was assessed using the Demirjian method, while skeletal maturity was evaluated using the cervical vertebral maturation stage (CVMS) method described by Baccetti. Data analysis was conducted using SPSS software version 27. The correlation between variables was calculated using Pearson’s correlation coefficient and Spearman’s rank correlation. The mean dental age of patients was found to be higher than their chronological age. Notably, the strongest correlation between dental age and chronological age for both males and females were observed at the first cervical vertebral maturation stage (CVMS1) highlighting its potential clinical relevance for early growth assessment. The positive Pearson correlation between dental age and chronological age was 0.894 in males and 0.876 in females. Moreover, a strong and significant positive correlation was found between dental age and skeletal age, with a Spearman’s rank correlation coefficient of 0.779 in males and 0.785 in females. Additionally, a strong and significant positive correlation was observed between chronological age and skeletal age, with a Spearman’s rank correlation coefficient of 0.783 in males and 0.707 in females. The results of this study indicate a significant positive correlation between chronological age and both methods of assessing physical development (dental age and skeletal age). The Demirjian method appears to overestimate dental age in the study population, suggesting a need to reassess its validity in Iranian population. Furthermore, the strongest correlation between chronological age and dental age was observed at the CVMS1 for both genders. These insights should be taken into account when planning growth modification treatments.