Relationship between Chronological Ageand Developmental Stages of the Mandibular Third Molar in ۱۲ to ۲۰ Years Old Orthodontic Patients in Shiraz

Background and Aim: Age estimation may be needed to plan treatment procedures in pedodontic, and orthodontics. Third molar is the last and most variable tooth to develop and may be used for age estimation in adulthood. The purpose of this study was to investigate relationship between chronological age and developmental stages of the mandibular third molar in a population of south Iran.Method: The Demirjian’s classification system was used to evaluate the developmental status of the mandibular third molars on the ۵۰۰ panoramic radiographs of orthodontic patients. The age range of patients was ۱۲ to ۲۰ years. Mean and Standard deviations of Chronological age for each developmental stages were calculated. One-way ANOVA and post-hoc Tuckey HSD test were used to compare the mean age and developmental stages of molar teeth. The age differences in the developmental stages between the genders was assessed. Correlation between calcification stages of the third molars and age was determined.Results: Crown calcification was completed at the mean age of ۱۳.۸ years, and root formation without apex closure was observed at the mean age of ۱۷.۵ years. At a mean age of ۱۸.۴ years apex closure was occurred. Males were advanced in the most of stages of calcification. A strong correlation between developmental stages of the lower third molars and chronological age was found in both genders.Conclusion: The present investigation could provide reference data for third molar development in our population. Developmental stages of mandibular third molars showed a strong correlation with age. The lower third molars developed earlier in males than females. 

Keywords:

Chronologic Age , Third Molar Tooth , Developmental Stage , Iranian population