Evaluation of the prevalence of dental agenesis through the use of orthopantomography in a sample of subjects residing in Lombardy and Piedmont regions.

Aim: Dental agenesis is one of the most frequent dental anomalies, with a prevalence varying from 1.6% to 36.5%, depending on the populations studied. The patient's age at diagnosis, sex, and ethnic differences are considered possible influenting factors that can explain such a wide range of prevalence. The objective of the study was to define the frequency of dental agenesis in a sample of subjects living in Piedmont and Lombardy regions of Italy.

Materials: X-rays, already taken for other diagnostic purposes, were collected. Orthopantomographies belonging to subjects born after 1995 and aged between 7.9 and 16.9 years were selected. It was assessed the presence of each tooth, except for third molars since they are frequently absent due to their variability. If a tooth was missing and the patient had additional radiographs, the other radiographs were evaluated to confirm the diagnosis or to rule out a delayed calcification or the presence of a malposition tooth.

Results: Orthopantomographies were collected from 1,020 subjects and 98 of them presented agenesis, with a prevalence of 5% for females and 4.61% for males. The most affected teeth were 35 and 45, followed by 12 and 22. The lower arch was more frequently involved by agenesis: there were 107 teeth absent in the mandibular arch and 83 in the maxillary arch.