Cariogenicity of a Milk-Based Drink Used as a Dietary Supplement for Older Adults Using a Root Caries Experimental Model

The aim of this study was to evaluate the cariogenicity of a milk-based drink intended for older adults that was used as part of a governmental initiative in Chile to improve their nutritional conditions. This drink contains a high concentration of sugars, which can contribute to root caries development. To test this hypothesis, an experimental biofilm/caries model was used. Dentin slabs were used to grow biofilms of Streptococcus mutans UA159. Slabs/biofilms were exposed 3× per day to bovine milk with different fat content, the milk-based drink, and the milk-based drink supplemented with 10 g of sucrose added per serving. Slabs exposed to 10% sucrose or 0.9% NaCl were used as positive and negative controls, respectively. Biofilms were analyzed for bacterial counts and acidogenicity. Dentin demineralization was estimated by the loss of surface microhardness and integrated mineral loss. Results were compared by analysis of variance and Tukey’s test. The milk-based drink showed higher acidogenicity than milk with its entire (whole) or reduced total fat content (skim). The milk-based drink supplemented with ­sucrose had similar acidogenicity as the 10% sucrose positive control (p = 0.506). Whole milk exposure elicited lower bacterial counts than the positive control, the milk-based drink, and the milk-based drink supplemented with sucrose (p = 0.002; 0.006 and 0.014 respectively). Although skim milk induced higher demineralization than whole milk, both milk types produced lower demineralization than the milk-based drink. Regarding integrated mineral loss, demineralization induced by the milk-based drink and the milk-based drink supplemented with sucrose was similar to that induced by the positive control and skim milk (p > 0.05). Sugar-containing milk-based drinks used as dietary supplements for older adults may be highly cariogenic and could represent a potential risk for root caries.