Effects of Milk Formulations and Streptococcus mutans on pH

Objectives: Previous studies have suggested that human maternal milk, compared to commercial formulation and bovine milk affect to bacterial colonization and pH changes, contributing to childhood caries development. Research Objective: The objective to the current in-vitro study is to understand the effects of human maternal milk, compared to commercial milk formulations and bovine milk and its effects on pH, contributing to carcinogenicity under a high Streptococcus mutans and sucrose load.
Methods: Methods: permanent teeth segments lacking existing carious lesions were cultured in donated human breast milk, Similac commercial formula, or whole bovine milk in the presence or absence of 1X10⁷ CFU/mL S. mutans and 10% sucrose (n=3 segments per treatment group).
Results: Results: pH at 6 days and 28days of incubation was measured as fold change relative to the past 24hrs. After 6 days of incubation, the pH of permanent teeth cultured with donated breast milk demonstrated significant drop in pH, compared to formula and bovine milk. Addition of sucrose and S. mutans augmented this difference 1.43-fold and 1.67-fold, compared to formula and bovine milk, respectively (two-way ANOVA). In the absence of either sucrose or S. mutans, the difference in pH was not observed. The differences persisted at 28days of incubation with sucrose and microbial components. Conclusion: The results suggest that in-vitro, under high bacterial and fermentable sugar load, human milk has high ability to potentiate drop in pH in the cariogenic process as early as 1 week and even into 4 weeks.
Conclusions: However, pH is necessary, but not sufficient in promoting carcinogenicity, as preliminary histological and biofilm data from the current study suggests that human breast milk may still provide protective effects against caries development. Thus, nursing mothers should be educated on potential increased caries risk of their child due to increased acidity of human milk after the introduction of additional carbohydrates.