Recent developments in the biologic production of ammonia and the use of ammonia and carbamide in caries prevention

1. 1. More ammonia is formed in saliva than can be derived from the conversion of salivary urea. 2. 2. Amino acids are an important source of ammonia, and seventeen have been found to occur in saliva. 3. 3. Sugar in saliva has a depressing effect on ammonia production as well as a stimulating effect on acid formation. 4. 4. The salivary content of four amino acids was influenced by the nitrogen content of the diet. 5. 5. Dibasic ammonium phosphate (5 per cent) and urea (3 per cent) when in combination have a synergistic effect in inactivating glycolytic bacterial enzyme systems in saliva that produce lactic acid and in inhibiting the growth of lactobacilli and yeasts. 6. 6. Clinical studies indicate that the conscientious use of a dentifrice containing these agents produces a reduction in caries activity, but a larger number of young individuals must be studied before conclusions can be drawn.