Cariogenic oral flora and its relation to dental caries

Many attempts have been made to establish the risk profile of dental caries; however, no diagnostic procedures are yet available to reliably predict such risk particularly among the pediatric and adolescent population. Age of subject, a history of caries affecting the primary dentition, the prevalence of Streptococcus mutans, pH values, salivary flow, and the frequency and amount of sugar consumption have been the factors most studied. A cross-sectional study is made of schoolchildren in the 12-13-year age-range to evaluate the relationship between dental caries and CFU/ml of S. mutans and Lactobacillus, salivary buffer capacity, and salivary flow. Likewise, an evaluation is made of the predictive value of the variables, bacterial count and salivary pH with respect to caries. A total of 167 children were subjected to oral examination to establish the DMFT and DMFS indices, followed by the collection of saliva for quantitating S. mutans, Lactobacillus, pH and salivary flow, by the Dentocult (SM)(LB) and Dentobuff systems (Vivadent). The data obtained were subjected to descriptive analysis, comparisons among variables were made by nonparametric testing with a confidence level of 95 percent. Test predictive value was studied in terms of sensitivity, specificity, positive and negative predictive values, and probability ratio. Statistically significant (p < 0.001) correlations were observed between the caries indices and bacterial counts. No significant association was recorded with the rest of the variables studied. Bacterial counts as well as salivary buffer capacities exhibited greater negative than positive predictive values, i.e., they were more effective in identifying healthy individuals than patients who required treatment.