Which statement best describes the relationship between coronal and root caries and pH effects on acid dissolution?

Which statement best describes the relationship between coronal and root caries and pH effects on acid dissolution?

• A. Both dissolve faster at higher pH
• B. Coronal caries dissolves slower at low pH; root caries dissolves faster at higher pH
• C. Coronal caries dissolves faster at high pH; root caries dissolves slower at high pH
• D. Neither is affected by pH

Answer: (B)

The amount that tooth minerals dissolve in an acid environment depends on the substrate’s composition and structure. Enamel on the crown is highly mineralized and relatively resistant to acid attack, so it requires a stronger, more erosive drop in pH to begin substantial dissolution. Root surfaces, made of cementum and dentin, have more organic matrix and dentinal tubules, making them less resistant to acid and able to demineralize at higher (less acidic) pH values than enamel. Because of this difference in vulnerability, coronal (enamel) caries tend to show slower dissolution under mildly acidic conditions, while root caries can dissolve more readily as the pH rises toward the dentin/cementum dissolution threshold. This pattern aligns with the statement that coronal caries dissolves slower at low pH and root caries dissolves faster at higher pH, reflecting the distinct pH thresholds and solubility of enamel versus root substrates.

The amount that tooth minerals dissolve in an acid environment depends on the substrate’s composition and structure. Enamel on the crown is highly mineralized and relatively resistant to acid attack, so it requires a stronger, more erosive drop in pH to begin substantial dissolution. Root surfaces, made of cementum and dentin, have more organic matrix and dentinal tubules, making them less resistant to acid and able to demineralize at higher (less acidic) pH values than enamel. Because of this difference in vulnerability, coronal (enamel) caries tend to show slower dissolution under mildly acidic conditions, while root caries can dissolve more readily as the pH rises toward the dentin/cementum dissolution threshold. This pattern aligns with the statement that coronal caries dissolves slower at low pH and root caries dissolves faster at higher pH, reflecting the distinct pH thresholds and solubility of enamel versus root substrates.