Salivary Cariogenic Bacteria Density in Down Syndrome Children and Adolescents

Objectives: To assess and compare salivary S. mutans, S. sobrinus, and streptococci densities between groups of Down syndrome and non-Down syndrome children and adolescents and their correlation with dental caries experience.
Methods: This study included a sample of 30 Down syndrome children and adolescents (G-DS) and 30 age- and sex-matched non-Down syndrome subjects (G-ND). Dental caries experience was estimated by the numbers of decayed, missing, and filled teeth in the primary dentition and the permanent dentition. Unstimulated whole saliva samples were collected from all participants. The fluorescence in situ hybridization technique was used to identify the presence and densities of the bacteria. The statistical analysis included chi-square, Student’s t tests and Spearman’s correlation.
Results: The G-DS exhibited a significantly higher caries-free rate (p < 0.001) and a lower S. mutans salivary density (p < 0.001). No significant differences were found in the salivary densities of S. sobrinus or streptococci between the groups (p = 0.09 and p = 0.21, respectively). In neither group were the salivary S. mutans or S. sobrinus densities associated with dental caries experience.
Conclusions: The reduced dental caries experience observed in this group of Down syndrome children and adolescents cannot be attributed to lower salivary S. mutans densities, as determined with the fluorescence in situ hybridization technique.