Associations between dietary intake, dental caries experience and salivary bacterial levels in 12-year-old English schoolchildren.

A population of 328 12-yr-old English schoolchildren, consuming their normal diets, was investigated in a cross-sectional study to determine the interactions between caries experience, oral hygiene status as gingival index (GI), dietary intake (as number of eating events per day and the number of eating events per day at which sugar-containing foodstuffs, confectionery or starch-containing foods were consumed) and salivary levels of caries-associated micro-organisms (mutants streptococci, lactobacilli and yeasts). The mean (+/- SD) decayed, missing and filled surfaces (DMFS) (excluding precavitation lesions) score was 3.05 +/- 3.85 and 5.72 +/- 5.00 (including precavitation lesions). The DMFS scores were significantly related to the salivary levels of caries-associated micro-organisms and to the number of eating events per day for total number of eating events and the number of eating events at which sugar-containing foods or confectionery were consumed. These associations were apparent in both bivariate and partial correlation coefficients with the caries-associated micro-organisms and GI controlled. The total daily intakes of food types, except for starch, were not associated with caries experience. No significant correlations were found between intake of food types and salivary levels of caries-associated micro-organisms except that the mean number of confectionery-eating events was correlated with lactobacillus levels (r = 0.136, p < 0.01). The salivary levels of mutans streptococci, lactobacilli and yeasts were significantly correlated with GI scores. These data do not indicate simple associations between dietary intake, caries and levels of caries-associated micro-organisms. Poor oral hygiene, in children consuming unrestricted diets, may influence the salivary levels of mutans streptococci, lactobacilli and yeasts irrespective of the frequency or amount of sugar consumed. Multiple regression analyses revealed that three variables--GI (probably an indicator of toothbrushing behaviour with a fluoride-containing toothpaste), salivary concentration of lactobacilli and frequency of ingestion of confectionery/sugary foods--were independently and positively related to caries experience.