[Saliva, a physiological medium].

Plaque and plaque fluid, rather than saliva, are of prime importance in determining the result of the interaction between tooth enamel and its environment. The concentration of calcium and phosphate ions is higher in plaque fluid than in saliva. Local supersaturation may result in the remineralization of white spot lesions or in the formation of calculus. The latter may be inhibited with containing dentifrices. Undersaturation, resulting from bacterial acids production, promotes dental caries. Fluorides are effective against caries, although the limited transporting properties of saliva would be recognized when designing caries preventive treatments. Suppleting saliva with calcium and phosphat ions through mouthrinses is another method to fight caries, while stimulation of the secretion by chewing gum is also very effective.