Title of article :
Correlation between chronological age and third molar developmental stages in an Iranian population (Demirjian method)
Author/Authors :
Khosronejad, Aria Graduate , Navabi, Manijeh Departments of Dental Anatomy and Morphology - Islamic Azad University, Tehran , Sakhdari, Shirin Departments of Dental Anatomy and Morphology - Oral and Maxillofacial Radiology - Dental Branch - Islamic Azad University, Tehran , Rakhshan, Vahid Departments of Dental Anatomy and Morphology - Islamic Azad University, Tehran
Abstract :
Background: Third molar development is the only available tool for estimating the age of individuals
after puberty. Since this tooth has very high interethnic variability, formulas calculated to estimate
the age from its development stages cannot be generalized to other populations and should be
adjusted for each region. Therefore, this study was conducted to evaluate this method in a sample
of Tehran individuals for the first time, and also to compare the development of third molars across
sexes and arches, and to estimate cutoff developmental stages for legal minor/major identification.
Materials and Methods: A total of 150 dental patients aged between 15 and 25 years old
were prospectively enrolled, and their Demirjian stages were recorded. The associations between
chronological age and Demirjian stages were evaluated. Dental formation was compared between
sexes and jaws. Cutoff stages were determined to identify legal minor/major cases (above or below
18 years old). Age estimation formula was found for this population.
Results: Of the 150 included patients, 56 were males. The difference between the ages of males
and females at each given developmental stage was nonsignificant (P > 0.05), except for the H stage.
Age difference between same stage teeth of the maxilla and mandible was nonsignificant. Each of
the G and H stages was significantly above 18 years old (P < 0.001). Furthermore, E and F stages
were below 18 years old (P < 0.001). All the correlations between Demirjian stages and age were
above 90% (all P < 0.001). Third molar development was positively affected by the chronological
age (P = 0.000) and being maxillary (P = 0.000) but not sex (P = 0.113). Regression formula for age
estimation was: age = 6.52+ (0.64 × sex) + (0.32 × arch) + (1.86 × Demirjian stage).
Conclusion: Development of third molar might complete after the age 22. Iranian individuals with
third molars at the G and H stages are likely above 18 while those at E and F are likely below 18. Pace
of molar development differs for jaws, but intergender differences are open to further investigations.
Keywords :
Age determination by teeth , forensic anthropology , forensic dentistry , growth and development , third molars
Journal title :
Astroparticle Physics
