Caries is an interaction between _____ and ______.

• A. Oral flora; dietary carbohydrates (sugars)
• B. Saliva; tooth enamel
• C. Genetics; fluoride
• D. Bacteria; minerals

Answer: (A)

Caries arises from the acid produced when dental plaque bacteria metabolize fermentable carbohydrates in the diet. The bacteria in the oral biofilm convert sugars to organic acids, which lower the local pH. When sugar exposure is frequent, these acids persist and dissolve the mineral content of enamel, causing demineralization and eventual decay. Saliva helps by buffering acids and supplying minerals for remineralization, but the decisive interaction is between the oral flora and dietary sugars. The other options miss this key driver: they either emphasize saliva or minerals, or introduce factors like genetics or fluoride that influence progression rather than initiate the carious process.