Prevalence of malocclusion in mentally retarded young adults.

Occlusal anomalies were recorded in 218 mentally retarded young adults, aged 13-19 yr. Down's syndrome was diagnosed in 37 cases. Among the Down's syndrome individuals 41% had mandibular overjet, 54% mesial molar occlusion, 38% frontal open bite and 65% crossbite. Also, the mentally retarded subjects without Down's syndrome had markedly increased frequencies of some of the anomalies when compared to normal individuals. Thus, 27% had extreme maxillary overjet, 6% mandibular overjet, 17% mesial molar occlusion, 23% frontal open bite and 29% crossbite. Orthodontic dental service for the mentally retarded has been neglected for a long time. Though many factors may contraindicate treatment, it should in many cases be possible to improve the dental situation for this group, thereby helping these patients to a better oral function.