Third molar agenesis may be linked to supernumerary tooth formation, according to a study published in Orthodontics and Craniofacial Research.

Tooth agenesis occurs when one or more teeth are congenitally absent. About 22.6% of individuals may experience missing third molars in their permanent dentition. Female patients are often about 14% more likely to experience third molar agenesis compared with male patients. The genetic causes of third molar agenesis have also been implicated in tooth shape and size discrepancies as well as craniofacial bone morphogenesis. As a result, missing third molars can affect the face shape and size.

In the retrospective study, investigators conducted a record review across various orthodontic clinics—including the Department of Orthodontics at the University of Bern, the University of Basel, and two private practices in Switzerland; as well as the National and Kapodistrian University of Athens and the Aristotle University of Thessaloniki—to identify 380 White patients of European descent who underwent panoramic radiographs between the ages of 10.5 and 50 years from 2002 to 2023. They noted that 50% of the patients had nonsyndromic permanent supernumerary teeth and 50% of them were age- and sex-matched controls with full dentition.

After analyzing the panoramic radiographs, the investigators identified a total of 244 supernumerary teeth among the patients involved in the study. Among the patients in the supernumerary tooth group, 76.2% and 82.4% of male and female patients, respectively, had a single supernumerary tooth and 16.4% and 17.6% of them had two supernumerary teeth.

The investigators found no sex-based differences in third molar agenesis severity. They discovered that the prevalence of third molar agenesis was similar between both groups (14.7%). Compared with controls, the patients in the supernumerary tooth group had 53 vs 67 missing third molars (P = .862). However, the patients with supernumerary tooth formation had a lower ratio of bilateral to unilateral third molar agenesis compared with controls (P = .026).

The investigators emphasized that the presence of supernumerary teeth did not impact the risk of third molar agenesis. They hope their findings can help physicians predict and diagnose third molar formation and assist with treatment planning.

A full list of disclosures can be found in the original study.