What is the Stephan curve and why is it important for understanding caries risk?

What is the Stephan curve and why is it important for understanding caries risk?

• A. The Stephan curve depicts a rapid drop in plaque pH after sugar ingestion followed by a gradual return to baseline; prolonged acidity increases demineralization risk and caries.
• B. The Stephan curve shows a gradual rise in plaque pH after sugar ingestion.
• C. The Stephan curve measures saliva flow rate.
• D. The Stephan curve demonstrates temperature changes in the oral cavity after meals.

Answer: (A)

The Stephan curve shows how dental plaque pH changes over time after a carbohydrate challenge. When sugar is ingested, plaque bacteria rapidly ferment it and produce acids, causing a sharp drop in pH within minutes. Buffers in saliva and remineralization processes then raise the pH back toward baseline, but the time spent at low pH matters. If the plaque pH remains below about 5.5 for an extended period, enamel demineralization can occur, increasing caries risk. This curve is useful because it links sugar exposure to acid attacks and the window for remineralization, helping explain why frequent or prolonged sugar intake elevates caries risk. The other statements don’t fit because the curve does not show a gradual rise in pH after sugar, it’s not a measure of saliva flow, and it does not depict temperature changes in the mouth.

The Stephan curve shows how dental plaque pH changes over time after a carbohydrate challenge. When sugar is ingested, plaque bacteria rapidly ferment it and produce acids, causing a sharp drop in pH within minutes. Buffers in saliva and remineralization processes then raise the pH back toward baseline, but the time spent at low pH matters. If the plaque pH remains below about 5.5 for an extended period, enamel demineralization can occur, increasing caries risk. This curve is useful because it links sugar exposure to acid attacks and the window for remineralization, helping explain why frequent or prolonged sugar intake elevates caries risk. The other statements don’t fit because the curve does not show a gradual rise in pH after sugar, it’s not a measure of saliva flow, and it does not depict temperature changes in the mouth.