How does saliva protect teeth in the oral cavity?

Saliva provides multiple protective functions: (1) Acid neutralization - bicarbonate and phosphate buffer systems raise oral pH after acid challenges; (2) Remineralization - calcium and phosphate ions repair early enamel lesions; (3) Antimicrobial activity - immunoglobulins (IgA), lysozyme, lactoferrin, and peroxidases inhibit bacterial growth; (4) Mechanical cleansing - wash-away of food debris and bacteria; (5) Lubrication - mucins protect mucosa. Saliva does not enhance bacterial growth; rather, it contains antimicrobial components that limit microbial activity.