Dietary habits, gingival status and occurrence of Streptococcus mutans and lactobacilli as predictors of caries in 3-year-olds in Sweden.

The aim was to study whether dietary habits, oral hygiene expressed as gingival status, and presence/absence of S. mutans and lactobacilli, singly or in combinations, could be used as caries predictors. Sensitivity, specificity and predictive values for positive (PV+) and negative tests (PV-) were calculated. 133 children, 3 yr of age, were examined for caries and presence/absence of S. mutans and lactobacilli. Three levels of gingival status and dietary habits, respectively, were registered. Two groups in respect of dietary habits and oral hygiene were formed by stepwise pooling of the caries data for the nine possible combinations of oral hygiene and dietary habits, setting the most discriminating border (screening level) where sensitivity (0.86) and specificity (0.69) simultaneously reached their highest value. PV + was 0.58 and PV- 0.91. Higher predictive values were obtained when presence/absence of lactobacilli and of S. mutans were combined. Combinations of defined levels of dietary habits, gingival status and presence/absence of lactobacilli showed sensitivity 0.87, specificity 0.95, PV + 0.87 and PV- 0.95, presence/absence of S. mutans sensitivity 0.94, specificity 0.76, PV + 0.74 and PV- 0.95. A two-step prediction, with gingival status as the first predictor and presence/absence of lactobacilli or S. mutans as the second, was the most efficient when lactobacilli were involved.