[Hypodontia with anlage of all four third molars]

Orthopantomographic films and anamnestic data of 1553 orthodontic patients presenting four third molars were evaluated for tooth agenesis. Agenesis was found in 94 patients (6.1%). There were no significant differences between male and female patients. The most commonly missing teeth were the lower second premolars followed by the upper lateral incisors and the upper second premolars in decreasing order of frequency. Compared with the data in the literature, these results suggest that agenesis occurs less frequently in patients with anlage of all four third molars.