Agenesis of Third Molars among Turkish Children between the Ages of 12 and 18 Years: A Retrospective Radiographic Study

Evaluation of the frequency of third molar agenesis according to different age groups

PURPOSE

Third molars (M3s) are the most common congenitally missing teeth. The aim of this study was to compare the frequency of M3 agenesis in two different age groups.

METHODS

This study examined the panoramic radiographic images of 1036 patients. Two groups, each consisting of 518 patients, were arranged based on age ranges. The patients aged 12 to 19 years were in the first group and those 20 years and older were in the second group. The frequency of M3 agenesis was examined in both age groups. The distribution of M3 agenesis by sex and jaw was also recorded, along with the number of M3s affected by agenesis. Chi-square tests were used to examine the relationships between categorical variables.

RESULTS

M3 agenesis was observed in 29.3% and 20.5% in the first and second groups, respectively; the difference was statistically significant (P < .01). It was more common in female (27.3%) than in male patients (21.4%), and in the maxilla (11.2%) than in the mandible (5.8%), and the differences were statistically significant (P < .05). It was mostly observed forthemaxilla right M3 (18) (30.9%) and in the single quadrant of the jaws (9.7%).

CONCLUSIONS

The frequency of M3 agenesis was more common in patients aged 12 to 19 years than in those aged 20 years and older. Additionally, M3 agenesis was more common in females and in the maxilla.

Evaluation of third molar agenesis associated with hypodontia and oligodontia in turkish pediatric patients

Purpose

To evaluate the association between third molar (M3) agenesis and hypodontia and oligodontia in pediatric patients by using panoramic radiography.

Materials and methods

Panoramic radiographs of 1,471 patients (899 females; 572 males) and 5,884 teeth were retrospectively evaluated. The age and gender of the patients were recorded. Patients ages 9-15 years old were included in the study. The mean age was 12.76. The agenesis of M3 teeth and the relationship between M3 agenesis and hypodontia and oligodontia were recorded according to findings from the upper and lower jaw, in both the right and left locations, along with the number of M3 with agenesis. Data were analyzed using chi-square and McNemar tests (p<0.05).

Results

A total of 1,319 (89.7%) patients had all M3 teeth present in the mouth, while the other 152 (10.3%) had congenital agenesis in one or more teeth. The number of teeth in which M3 agenesis was seen, in order of the number of missing M3 teeth, the percentages were 2.6% for one, 2.4% for two, 1.0% for three and 4.3% for four missing teeth.Hypodontia was detected in 37 patients and oligodontia was detected in 3 patients.

Conclusion

The prevalence of M3 agenesis varies from one population to another. Two of the dental anomalies associated with M3 agenesis are hypodontia and oligodontia. In this study, M3 agenesis varied in terms of region and gender; hypodontia was also significantly higher in patients with missing mandibular M3.