RESUMEN
The purpose of this epidemiological study was to find correlation among dental caries and S. mutans in schoolchildren from a Protection Center. Quantitative and semiquantitative methods were employed to determine salivary concentration of mutans streptococci. The results showed that 44 percent of children had 1-3 dental caries, while 23 percent had 4-7. A direct relationship was found with the concentration of mutans streptococci in saliva. Both methods employed showed that the caries risk level, can be stabilized approximately in 5 x 105 UFCf S. mutans/mL saliva. Biochemical and serological characterisation of the isolated streptococci mutans group revealed that 95 percent was of biotype I, serotype c (c, e, f) belonged to S. mutans specie, and of 5 percent was S. sobrinus biotype IV, serotype (d, g, h). A direct correlation between decalcified areas and the quantity of salivary S. mutans was also found. Based in these results, a prediction about people in risk of develop dental caries, can be made, and so adequate prevention programs, can be established