Cariogenicity of different commercially available bovine milk types in a biofilm caries model.

PURPOSE

This study's purpose was to assess the cariogenicity of commercial bovine milk types in an experimental biofilm/caries model.

METHODS

Enamel and dentin slabs were used to grow biofilms of Streptococcus mutans UA159. Slabs/biofilms were exposed three times per day to commercial skim, semi-skim, whole, whole lactose-free, and whole with 10 percent sucrose-added bovine milk and to 10 percent sucrose and 0.9 percent sodium chloride as positive and negative caries-control, respectively. Biofilms were analyzed for bacterial counts, biomass, proteins, and polysaccharide production. Slab's demineralization was assessed by loss of surface microhardness and the biofilm acidogenicity by medium pH.

RESULTS

Only whole and whole lactose-free milk kept pH above the demineralization threshold, inducing the lowest demineralization in both enamel and dentin (P<.05). Skim and semi-skim milk induced similar demineralization to the sucrose control, albeit slightly lower for semi-skim milk (P<.05). Whole and whole lactose-free milk produced lower biomass and less insoluble polysaccharides than the other treatments in enamel and dentin (P<.05). Adding 10 percent sucrose to whole milk turned it as cariogenic as 10 percent sucrose solution.

CONCLUSION

Bovine whole milk seemed less cariogenic than sucrose and the other commercial milk types, but not anticariogenic. Fat content in milk seemed to reduce cariogenicity of the fluid.