Which statement is most accurate regarding salivation and remineralization of tooth enamel?

Saliva plays a critical role in remineralization of early carious lesions. Saliva is supersaturated with calcium (Ca2+) and phosphate (HPO42-) ions relative to enamel hydroxyapatite. Following a cariogenic acid challenge, saliva neutralizes plaque acids (via bicarbonate buffering), and when pH rises above the critical pH (5.5 for enamel), Ca2+ and phosphate ions deposit back onto the enamel surface, reversing early demineralization. Fluoride enhances this process by forming fluorohydroxyapatite. Salivary flow rate is NOT constant — it is stimulated by food and decreases during sleep. Diet significantly affects salivary composition and pH.