[Survey on oral hygiene status in children with Down's syndrome and mental retardation].

The purpose of this study was to compare the periodontal condition of children with Down's syndrome and other types of mental retardation with normal children. We used two indexes: a plaque index and a gingival index. By means of the student t-test and ANOVA statistical procedure, we found the following. Mentally retarded children had a higher average intelligence than children with Down's syndrome, and significant differences existed among the three groups on both the plaque index and the gingival index, while sex had no influence on these results.