Mutans Streptococci and Caries Experience From Birth to Age 6-years

Objectives: To determine the presence of mutans streptococci (MS) and lactobacilli (LB) from birth to 6 years in children with and without caries experience.
Methods: Seventy-five children with caries and 75 children with no caries experience were randomly selected from a pre-existing birth cohort. Salivary samples were collected from the same child 6 monthly from birth until 6 years of age. MS and LB presence were assessed using the CRT-Bacteria assay (Ivoclar-Vivadent, Melbourne, Australia).
Results: Although 2 children experienced their first caries at 2 years of age, almost half (45%) were caries-free until 5 years of age. In children with caries, the prevalence of MS from 18 months of age was consistently higher at all time points than in caries-free children (p<0.05). At 18 months of age, 28% of children with caries were positive for MS compared with 11% of caries-free children (p=0.018). Similarly, at 6 years of age, 56% of children with caries were positive for MS compared with 32% of caries-free children (p=0.004). In children with caries, 65% were positive for MS on ≥5 assays (out of 12) compared with 19% of the children without caries (p<0.001). In contrast, LB presence was higher in the children with caries at each time point only from 5 years of age (p<0.05).
Conclusions: Children with caries have an increased prevalence of MS and an increased frequency of assays positive for MS compared to caries-free children. This study was funded by the National Health and Medical Research Council of Australia (Grant No.1046779).