Prevalence and Gender Distribution of Permanent Tooth Agenesis among Jordanian Dental Patients: A Cross-Sectional Survey

Objective: Tooth agenesis (hypodontia) is a common dental anomaly and an important aetiology of malocclusion. The aim of this study was to determine the pattern and distribution of hypodontia among a sample of Jordanian dental patients and to investigate the differences between genders, then compare the findings with those reported in the literature. Methods: Orthopantograms taken within a two-year interval were surveyed by three examiners to detect agenesis of permanent teeth (excluding third molars). Orthopantograms of 8,225 patients (males=43%, females=57%) between the ages of 6 to 64 years were examined and descriptive data of hypodontia was analyzed and influence of gender on the distribution was investigated. Results: The prevalence of hypodontia was 3.7% (n=302, males=3.3%, females=3.9%) with no significant difference between genders (P=0.17). Average number of missing teeth per patient was 1.9 (males=1.8, females=2.0) with the majority (85.4%) having one or two missing teeth and only 3.3% suffered oligodontia. Hypodontia was more common in the maxilla than the mandible (P<0.05) and on the left side in unilateral cases (P=0.036). The most frequent missing tooth was the maxillary lateral incisor (2.05%) followed by the mandibular second premolar (1.22%). Conclusions: The prevalence of hypodontia among Jordanian dental patients was compatible with those reported for other ethnic groups with some differences found in the analyzed patterns. There was no influence of gender on the distribution of hypodontia, which suggest weak evidence for the X-linked inheritance for this anomaly.