Cariogenicity and acidogenicity of human milk, plain and sweetened bovine milk: an in vitro study

The objective of the present study was to determine the acidogenicity and cariogenicity of human breast milk and plain and sweetened packaged bovine milk.

First all milk specimens were inoculated with a cariogenic strain of Streptococcus mutans (SM). The culture pH and number of colony forming units (cfus) was assessed. Second, the buffer capacity of all milk specimens was evaluated by mixing with acid. Finally, enamel windows were created on extracted primary maxillary incisors and colonized with SM. Enamel demineralization and caries progression were assessed visually, histologically, and radiographically at the end of twelve weeks.

Plain and sweetened packaged bovine milk (BM) supported greater bacterial growth and caused more fermentation than human breast milk (HBM). The buffer capacity values for plain and sweetened bovine milk were highest; HBM, however had poor buffering capacity. The progression of the carious lesions into the dentin was most severe for the sweetened bovine milk.

HBM and plain bovine milk are relatively cariogenic in an in vitro caries model in the absence of saliva. However, supplementation with sugar exponentially enhances the cariogenic potential of the natural milk.