BACKGROUND The present study was performed with the following aims: (1) to assess the relationship between skeletal age, measured using the cervical vertebral maturity (CVM) method, and chronological age; (2) to determine the correlation of skeletal and chronological age to the cortical thickness of the lower border of the mandible using the linear radiomorphometric; and (3) to explore the relationship between these indices and skeletal malocclusion type. METHODS The data were collected from the records of 180 patients, including 57 males (31.7%) and 123 females (68.3%). The data were based on the panoramic and lateral cephalograms of each patient. The CVM stages were determined on the basis of the patients' lateral cephalograms. Three radiomorphometric indices were measured: AI, MI and GI. The patients were divided up into three groups of skeletal malocclusion: Class I, II, and III. For all the tests, statistical significance was set at P<0.05. RESULTS The relationship between chronological age and skeletal age was 0.496. Furthermore, with an increase in chronological and skeletal age, the cortical thickness of the lower border of the mandible and consequently the radiomorphometric indices increase, except for the GI (P > 0.05). Lastly, the relationship between GI and skeletal malocclusion type proved significant. CONCLUSIONS AI and MI were found to increase significantly with increasing age, so the assessment of mandibular radiomorphometric indices could be clinically useful in estimating of the growth and maturation of the mandible. Key words:Orthodontics, Radiomorphometric indices, Skeletal age, Skeletal malocclusion.