Dental caries and mutans streptococci in selected groups of urban and native Indian schoolchildren in Mexico

Two groups of Mexican children aged 12-14 yr were examined for dental caries and salivary mutans streptococci counts. One hundred lived in Mexico City and 100 belonged to a native Mazahua Indian population. The prevalence of caries, diagnosed according to WHO, was 90% in Mexico City and 82% in the Indian community. Mean DMFT was 5.98 and 3.57 respectively. Saliva samples were analyzed for mutans streptococci by the "Strip mutans" method. Further identification of the biotype/serotype was done. Mutans streptococci were found in 95% of the urban children and 75% of the Indians. There was a statistically significant difference in the prevalence of mutans streptococci between the city and the rural samples. Streptococcus mutans was more frequently found than Streptococcus sobrinus.