Analysis of orthodontic anomalies in mentally retarded developmentally disabled (MRDD) persons

For this epidemiologic study, 458 individuals with mental retardation and developmental disability (MRDD), from 6 to 87 years old, from the Lower Hudson Valley region of New York, were evaluated for the occurrence of orthodontic anomalies. High occurrence of both anomalies of intermaxillary relation, as determined by Angle's classification, and the anomalies of occlusion were found in these individuals when compared with the general population. An increased incidence of both acquired (i.e., open bite) as well as hereditary (i.e., prognathia) orthodontic anomalies correlated with the severity of mental retardation. In addition, an increased incidence of Angle class II malocclusion was found in persons with cerebral palsy and autism, and an increase of Angle class III malocclusion in persons with autism and Down syndrome. Moreover, it was found that 74% of MRDD persons had definitive malocclusion, while only 37% of the US general population of comparable age has definitive malocclusion. High incidence of malocclusion in this population remained present into old age, mainly due to a lack of treatment and the need to employ non-conventional orthodontic treatment in this population.