Which statement explains how medications that contain sugar or reduce salivary flow affect caries risk?

• A. They decrease caries risk
• B. They increase caries risk by providing fermentable sugars and reducing saliva
• C. They cure caries
• D. They have no effect

Answer: (B)

Medications can influence caries risk in two main ways: by adding fermentable sugars to the mouth and by reducing saliva.

When a medicine contains sugar, it provides readily fermentable carbohydrates for oral bacteria. Those bacteria metabolize the sugars to acids, which lower the pH at the tooth surface. If this acid attack occurs repeatedly and is not balanced by remineralization, the enamel begins to demineralize, increasing the likelihood of caries.

Separately, many drugs reduce saliva production, causing dry mouth. Saliva normally helps wash away sugars, buffers acids, and supplies minerals necessary for remineralization. With less saliva, acids linger longer, the buffering capacity drops, and bacteria can flourish. The combination of a sugary medication and reduced saliva markedly increases caries risk.