Which statement describes saliva's role in remineralization?

• A. It provides calcium and phosphate that help remineralization
• B. It inhibits remineralization during low pH
• C. It has no role in remineralization
• D. It promotes demineralization at neutral pH

Answer: (A)

Remineralization relies on minerals being available at the tooth surface and a favorable pH. Saliva furnishes calcium and phosphate ions that can redeposit into demineralized enamel when the surface has recovered to neutral or near-neutral pH. This mineral reservoir keeps the enamel in a state of supersaturation with respect to hydroxyapatite, allowing crystals to grow back into subsurface lesions and restore mineral density. Fluoride in saliva can further enhance this by forming fluorapatite, which is more resistant to acid.

Low pH drives dissolution, so remineralization is limited during acid attack until the pH rises again; saliva’s buffering helps this recovery rather than inhibiting remineralization. Because of this mineral supply and buffering effect, the statement that saliva provides calcium and phosphate that help remineralization best describes its role.