the pH of saliva lies within the range of 5.5–6.5; a pH of 5.5 generally is accepted as the threshold level for the development of dental caries. While the oral cavity may recover when the pH within the oral cavity drops below this threshold, prolonged exposure to this pH or frequent cycling from the optimal (that is, neutral) pH to a value below the threshold can result in a more rapid demineralization of enamel. Lowered salivary pH often is a consequence of bacterial digestion of sucrose, fructose, and similar carbohydrates, causing acidic byproducts to form in dental plaque. Tooth demineralization, however, also may occur due to dental erosion.