[Bacteriological examination of saliva of institutionalized severely mentally retarded persons with chronic rumination].

The purpose of this study was to investigate dental caries prevalence, the pH and the presence of bacteria in the saliva of institutionalized severely mentally retarded persons with chronic rumination. The results obtained were as follows: The prevalence of dental caries among the group with chronic rumination was higher than among the group not suffering from rumination. The viable cell number of mutans streptococci, lactobacilli and yeasts in the group with chronic rumination was significantly higher than that of group without rumination. These results suggested that the saliva of the group with chronic rumination creates a favourable environment for aciduric bacterial growth.