A Radiographic Study of Third Molar Agenesis in a Sample from the American Midsouth

The purpose of this study was to determine the frequency of third molar agenesis in a sample from the American Midsouth. The sample included 118 black males, 115 black females, 100 white males and 100 white females. Panoramic radiographs of the dentition for each individual were studied to ascertain whether any of the third molars was congenitally absent. The results were submitted to statistical analysis.

The results showed that white males have a significantly higher propensity to be congenitally missing a third molar than black males, with p<0.001. Likewise, whites are more likely to be missing a third molar in the mandible than blacks, with p=0.007 in males and 0.041 in females. There was no significant difference between the sexes for each ancestry, nor was there a significant difference between sides.

The lower frequency of third molar agenesis in blacks (5.6%) compared to whites (15.5%) is consistent with results of earlier studies. The frequency for the white sample closely matches reported frequencies for American whites in Middle America. Since there are few studies of third molar agenesis in admixed African populations, the results of this study can be used as a baseline for American blacks.