The author evaluates the effect of an oral hygiene programme in a group of 32 mentally affected subjects staying in a day home. The investigation lasted two years. The programme was based on repeated instructions and check ups of oral hygiene and the administration of fluoride preparations. Repeatedly the DMF, OHI-S, CPITN indexes were examined. The decline of new caries was almost continuous, already after one year it declined by 0.43 caries on average and during the subsequent year by 0.3 caries. The OHI-S value declined in two years by an average of 0.76 and CPITN by 0.36. The results revealed that the preventive programme improved significantly the hygiene of the oral cavity and reduced the increment of dental decay.

        Key words: preventive programme – mental affection – oral hygiene – cariosity