Mutans streptococci oral colonization in 12-30-month-old Brazilian children over a one-year follow-up period

Objectives: The infection levels of mutans streptococci were investigated d uring a one-year follow-up in children aged 12 to 30 months attending schoo l nurseries where a sucrose-rich diet was provided. Methods: Oral levels of mutans streptococci obtained from 101 children at baseline and after a one -year follow-up were compared by age, number of teeth, feeding habits, and presence of visible plaque at baseline. Baseline predictors and changes in mutans streptococci levels during the study were compared to caries inciden ce after one year Results: Fluctuations in mutans streptococci levels durin g the follow-up period were not related to feeding habits or presence of vi sible plaque. Mutans streptococci levels increased after one year among chi ldren aged 12 to 24 months, while a significantly higher proportion of thos e aged 25-30 months showed a decrease in mutans streptococci levels during the study. Multiple logistic regression analysis suggested that high levels of mutans streptococci (greater than or equal to 100 cfu) at baseline were associated with a higher caries increment, while reduction in mutans strep tococci was negatively associated with caries incidence. Conclusions: Our d ata suggest that despite early mutans streptococci infection and high expos ure to sucrose, mutans streptococci may achieve relatively stable levels af ter 2 years of age. Heavy colonization by mutans streptococci in an early a ge was related to an extremely high caries incidence during childhood, whil e decreasing levels of mutans streptococci can be associated to the decreas e in caries activity.