There is definite ammonia deficiency in salivas of caries-susceptible persons, and relatively high content of ammonia in salivas of caries-immunes.
In studies of human saliva the authors found marked differences between the amounts of ammonia in salivas of caries-immune persons and of caries-susceptibles. Ammonia in salivas of caries-susceptibles varied from traces to 8 mgms. per 100 cc. ; in salivas of caries-immunes, from 8 to 20 mgms. per 100 cc. In marked pyorrhea cases, the amount of salivary ammonia was very high. For these determinations the authors used the Folin-Bell colorimetric method—permutite to absorb ammonia ; released by sodium hydroxide ; nesslerized ; and amount read in a colorimeter. White and Bunting, and also Youngburg, questioned these findings, being unable to confirm them with the aeration method, which the authors also found less sensitive than the method on which they relied. The Folin-Bell method was further criticized because it was difficult in many cases to obtain sufficiently strong color reactions, at the dilution used, for accurate colorimetric readings—a criticism with which the authors agreed, although adhering to the finding that the amount of ammonia in saliva of caries-susceptibles is low, when estimated by the Folin-Bell permutite method. Recently the authors increased the amount of saliva used for the determinations and reduced the dilution, thus markedly increasing the color intensities. By this modification of the Folin-Bell procedure the authors’ original findings were confirmed.
References: Den. Cosmos, 1934; J. Am. Den. Assoc., 1935; J. Can. Den. Assoc., 1935.