Disturbances of dental development distinguish patients with oligodontia‐ectodermal dysplasia from isolated oligodontia

OBJECTIVE: To investigate phenotypic differences in dental development between isolated oligodontia and oligodontia-ectodermal dysplasia (ED). SETTING AND SAMPLE POPULATION: A total of 129 patients diagnosed with isolated oligodontia and 22 patients with oligodontia as part of ED were eligible. METHODS: The phenotype of dental development was assessed for the frequency of missing a certain tooth, dental age, development of each tooth present, abnormal size and abnormal shape of teeth. The data were analysed building linear, ordinal and logistic regression models. RESULTS: Compared to patients with isolated oligodontia, patients with oligodontia-ED missed more frequently central incisors and second molars in both jaws, and lateral incisors in the mandible (P < .05). Oligodontia-ED was associated with delayed development of the permanent dentition (β = -0.10; 95% CI: -0.17, -0.03). Specifically, the maxillary teeth: right central incisor, right lateral incisor, right second premolar and left second premolar were delayed approximately from 2 to 4 developmental stages. In addition, the left mandibular second premolar was 3 developmental stages delayed. Abnormal shape of teeth was 7 times more evident in patients with oligodontia-ED compared to patients with isolated oligodontia (OR = 6.54; 95% CI: 2.34, 18.28). The abnormal size of teeth was not a distinctive characteristic for oligodontia-ED. CONCLUSIONS: Oligodontia-ED distinguishes from isolated oligodontia by more disturbances in dental development. The abnormal shape of incisors and canines in a patient with oligodontia can raise suspicions for accompanying ectodermal abnormalities.