radiographic assessment of third molars development and it’s relation to dental and chronological age in an iranian population

background: the aim of the present study was to estimate chronological age based on third molar development and to determine the association between dental age and third molar calcifi cation stages. materials and methods: in this cross-sectional study, 505 digital panoramic radiographs of 223 males (44.2%) and 282 females (55.8%) between the age of 6 and 17 were selected from patients who were treated in departments of pediatrics and orthodontics of isfahan university of medical sciences between the years of 2009 and 2013. correlation between chronological age and third molar development was analyzed with spss 21 using spearman’s rank correlation coeffi cient, chi-square test and multiple regression statistical tests ( p < 0.05). results: all third molars demonstrated a highly signifi cant correlation with dental age ( p < 0.001). the teeth showing the highest relationship with dental age were mandibular left third molar in males and mandibular right third molar in females ( r s = 0.072). when multiple regression was used to predict dental age based on molar calcifi cation stage, the only signifi cant correlation was between maxillary left third molar in males ( p < 0.05). there was no statistically signifi cant correlation for any of third molars in females. relationship between chronological age and molars development stage was signifi cant in all age subgroups and in both gender ( p < 0.001). conclusion: strong correlation was observed between left third molars and dental age in males. results showed that third molar calcifi cation stage can be used as an age predictor and in general mandibular teeth seems to be more reliable for this purpose in both genders and in all ages. key words: chronological age, demirjian system, dental age