[Bruxism and rumination in the mentally handicapped].

In 1969 we started an investigation of the dental abnormalities and treatment in a severely and profoundly mentally retarded population in The Netherlands. In this study the occurrence of bruxism, rumination and the combination of both is reported. Especially the combination is serious, since it inevitably and remedilessly ruins the dentition. The remains have to be removed already at an average age of 30 years. These patients, usually males, were not even cooperative during the daily brushing of their teeth.