The Association Between Dental Anomalies and Hypodontia Among 9-20 Years Old Individuals in Ardabil City, Iran: A Causal-Comparative Study

The aim of this study was to evaluate the relationship between the prevalence of dental anomalies and tooth agenesis. In this retrospective study, the panoramic radiographs of 101 cases with tooth agenesis (except for the third molar) were studied and compared with those of a non-agenesis control group of 182 subjects. The subjects were within the age range of 9-20 years. The prevalence of dental anomalies in the agenesis group was compared with that in the non-agenesis group. The subjects with hypodontia showed a significantly lower prevalence of dental anomalies. In the group with tooth agenesis, the prevalence of another dental anomaly was lower (P=0.026) with the OR of 1.78. However, there was a higher rate of dental anomalies in the control group. The highest frequencies were observed for the agenesis of mandibular second premolar, then maxillary second premolar, and finally maxillary lateral incisors in this order. The prevalence of dental anomalies in the agenesis group was relatively low and evenly distributed among genders and jaws. The most commonly affected teeth were the mandibular second premolar, then maxillary second premolar, and lastly maxillary lateral incisors in this order.