Objective: This study evaluates timetable of calcification stages of the second permanent molars (SPMs) based on panoramic radiographic findings from a selected group of Iranian patients.

Methods: This descriptive, analytical and cross sectional study uses 715 panoramic radiographs of subjects with optimal quality between 5 to 17 years of age (n=60 for each age group) whom were selected from the referrals to the departments of Orthodontics and Pediatric Dentistry of at Tehran University of Medical Sciences, Iran. Patients with systemic diseases or any kind of syndromes were excluded. Calcification stages were determined based on Demirjian's classification. Data were analyzed using generalized estimating equation (GEE).

Results: Only 20% of SPMs of 5 year-olds were in their 2nd stage of calcification and the remaining showed higher stages. The mean age of crown completion was around 8.5 years while the mean ages of root completion for the open and closed apices were 13 years and 3 months and 15.5 years, respectively. Also calcification occurred at earlier ages among girls.

Conclusion: Timetable of calcification of SPMs is useful to predict the onset of puberty. Demirjian’s classification well matches Iranian population for determining calcification stage of SMPs.

Keywords: Permanent Molar, Tooth Calcification, Forensic Dentistry, Iranian Population

Key Messages: Mean age at different stages of calcification of the second permanent molars could be effective in forensic dentistry as well as for diagnostic and treatment purposes