Acidic beverages contribute to increasing risk by providing energy to acidogenic bacteria and by ___ of the biofilm to support cariogenic bacteria.

• A. Diluting the Biofilm
• B. Dehydrating the Biofilm
• C. Influencing the pH of the Biofilm
• D. Increasing the Thickness of Enamel

Answer: (C)

The important idea is that the biofilm’s pH controls how cariogenic bacteria behave. Acidic beverages give fermentable sugars that these bacteria metabolize into acid, dropping the pH inside the biofilm. When the biofilm becomes more acidic (often below about 5.5), the environment favors acid-tolerant, cariogenic species and promotes enamel demineralization because the oral fluids become undersaturated with calcium and phosphate. So, the risk isn’t just about providing energy to the bacteria, but about the pH shift in the biofilm that supports cariogenic activity. Diluting or dehydrating the biofilm wouldn’t enhance cariogenic risk in the same way, and increasing enamel thickness would actually mitigate risk.