The effect of caries scoring systems on the association between dental caries and Streptococcus mutans

The purpose of this study was to examine the effect of caries scoring systems on the association between caries indices and salivary counts of S. mutans in a group of ninety-eight three to five-year-old preschool children in Saskatoon, Canada. Caries was recorded using the WHO (1987) criteria and a modified scoring system(MC) in which questionable lesions (no soft walls or floor) were included as carious. Whole stimulated saliva was collected from each subject and S. mutans counts were determined (CFU/ml of saliva). Both dft(MC) = 1.03 and dfs(MC) = 1.53 were significantly different (p < .0001) from dft(WHO) = 0.69 and dfs(WHO) = 1.17, respectively. The S. mutans count was found to be significantly (p < .001) correlated with dft(MC), dfs(MC), dft(WHO) and dfs(WHO). When questionable carious lesions are included in caries indices, they appear to remain well associated with salivary S. mutans counts.