S. sanguinis to S. mutans Ratio Negatively Correlated with S-ECC

Severe early childhood caries (S-ECC) is strongly correlated with a cariogenic microbial causation. Objective: The purpose of this study was to examine the colonization and genomic diversity of oral microflora associated with S-ECC. Methods: The children diagnosed with S-ECC had at least 10 decayed tooth surfaces with involvement of the maxillary anterior teeth. Whole saliva and supra-gingival plaque samples were collected from children with S-ECC (N = 14) and children who were caries free (CF) (N = 8). Bacterial enumerations and species identification were obtained using conventional culture methods. Results: We found that 100% of S-ECC children and 62.5% of CF children were S. mutans positive. All CF children and 92.9% of S-ECC children were S. sanguinis positive. Although S-ECC children experienced higher levels of S. mutans (p <0.05) and total oral streptococci (p <0.01) compared to CF children, multivariable analysis found that only the ratio of S. sanguinis to S. mutans, ranging from -3.72 to 7.72 (log₁₀ CFU/ml), was negatively correlated with the severity of the disease (r=-0.824; p >0.001). Conclusion: These results suggest that S. mutans colonization alone in the oral cavity may not necessarily be accurate for identifying children at high risk for S-ECC. A S. sanguinis/S. mutans ratio of less than 3.0 (log₁₀ CFU/ml) might serve as a meaningful indicator for the prediction of caries in children.

Supported by the NIH/NIDCR Grant DE015706.