Cariogenicity of Human and Cow's Milks and Infant Formula

Objectives: Clear guidelines concerning infant foods and their association with childhood caries are vital to effective and consistent communication between mothers and healthcare providers. The objectives of this study were to measure the ability of S. mutans (SM) to form biofilm and demineralization in the presence of human milk (HM), bovine milk (BM), and infant formula (IF), with and without 10% added sucrose.
Methods: Biofilm formation was measured by adding 1X107 CFU/ml SM to HM, BM, and IF with and without 10% sucrose in culture plates. After 48 hour incubation (37°C), culture medium and free-floating bacteria were removed, wells washed and stained, washed again to remove unbound dye and dried. Ethanol (95%) was added, plates were shaken and absorbance of each well was read via spectrophotometer at 550 nm quantifying biofilm formation. In vitro caries progression was determined using extracted, non-carious teeth stored in 10% formalin. Coronal sections were coated with lacquer leaving a 2x3 mm enamel window, bathed and incubated in control and experimental solutions. Solutions were changed every 24 hours. At 2, 4 and 6 weeks, sections were analyzed visually and histologically. Depth of demineralized lesions was measured using standardized software.
Results: Significant variance existed between biofilm growth of SM in HM, BM and IF. IF had significantly greater biofilm formation compared to HM and BM. Adding 10% sucrose to each solution significantly increased its biofilm growth. Analysis of visual and histological data is pending.
Conclusions: Infant Formula has greater biofilm forming ability than Human and Bovine Milk. Adding 10% Sucrose significantly increases biofilm formation for all milks.