Radiographic Evaluation of Third Molar Development in Relation to Chronological Age, Gender and Jaws
Radiographic Evaluation of Third Molar Development in Relation to Chronological Age, Gender and Jaws
- 1. Statement of the problem:
Extraction of third molars are needed for gaining space in the posterior segment when distalization of the first and second molar is required for orthodontic purposes; in the event of severe dentoalveolar discrepancy, morphostructural alterations or ectopic impactions; and the impossibility of molar eruption etc. However, the proper time and method of prophylactic extraction are still contraversial. Third molar germenectomy appears to involve less morbidity than extraction carried out when molar root formation has been completed1 and it is preferred approximately at age 14. Additionally, the best time for prophylactic extraction of the third molars is defined to be the time when one-half to two-thirds of the roots have formed. Generally, this stage occurs between 16-18 years of age. However, there might be racial differences in the developmental stages of the teeth. The present study was performed to determine the developmental stages of the third molars in a sample of Turkish population between 12-17 ages and to compare third molar development according to sex, age and jaws.
2.Materials and methods:
Orthopantomograms with good quality of 322 Turkish patients, between the ages of 12-17 years were examined. Patients have no history of medical or surgical disease that could affect the presence and development of third molars and no missing left third molars in either jaws.
Maxillary and mandibular third-molar developmental stages on the left side were evaluated based on using the formation stages described by Demirjian et al.2(from Stages‘‘A’’ to ‘‘H’’).Number of the samples were tried to be matched in each age group and the sexes.
3. Methods of data analysis:
Descriptive statistics were presented using frequencies and the percentages. Mann–Whitney U-test was performed to determine the differences between sex, age and location. Statistical analysis was performed using the SPSS 20.0 package (SPSS Inc., Chicago, IL) for Windows. p<0.05 was considered significant
4. Results :
Among this sample of Turkish population, third-molar crown formation was observed to be complete at around the age of 14 in both sexes and jaws. One-half to two-thirds of the roots have been formed as earlier at 15 years of age. Moreover, third molars reached Stage H (complete root development according to Demirjian’s) as early as at 16 years for females and 17 years for males.
Maxillary third-molar development was commonly more advanced than mandibular third-molar, although these differences were not statistically significant in both sexes and ages.
In the ages of 12 and 13; the development stages in both jaws were lower for males than for females, on the contrary between the 14-17 ages the development stages in both jaws were higher for males than for females which were not found to be significant.
5. Conclusions
1. No significant differences were found in third-molar development between males and females, upper and lower third molars in each age.
2. The crown formation is commonly completed in 14 years which is suitable time for germenectomy.
3. One-half to two-thirds of the roots have been formed as earlier at 15 years of age as the best time for prophylactic extraction.
6. References
1. Chiapasco M, Crescentini M, Romanoni G. Germenectomy or delayed removal of mandibular impacted third molars: the relationship between age and incidence of complications. J Oral Maxillofac Surg 1995;53:418-22.
2. A. Demirjian, H. Goldstein and J. M. Tanner. A New System of Dental Age Assessment. Human Biology 1973; 45: 211-227.