Longitudinal study of caries and cariogenic bacteria in an elderly disabled population

A 2-yr longitudinal study was conducted among elderly disabled residents of a longterm care facility. Each of the 50 subjects examined at the beginning of the study had a mean of 14 teeth, with a mean of 6 carious and 6 restored teeth, per person. Most of the subjects had very poor oral hygiene, and 26 of them had dental plaque that produced cultures of mutans streptococci and lactobacilli in excess of 10(5) CFU/ml. At the end of the first year, 40 subjects were examined again and, apart from a decrease in the mean number of carious root lesions per person, there was very little change in their dental or microbial status. Although only 18 subjects were available at the end of the second year, they presented with fewer carious lesions after 2 yr. The reduction in caries appeared to result from the remineralization of tooth structure, but new lesions did appear in 33% of the 1-yr group, and in 78% of the 2-yr group. This dynamic environment around the teeth produced a mean net incidence of one lesion in the first year, and three lesions over 2 yr. There was a significant (P less than 0.05) association between large (greater than 10(5) CFU/ml) numbers of mutans streptococci and the development of new lesions, but there was no association between the dental status of the subjects and the dental treatment they received. Overall, the results indicate that caries is not rampant in this population.