1. 1. The buffering systems in saliva, salivary sediment, and plaque are discussed. Bicarbonate is the major buffer in activated saliva, phosphate accounting for the remainder of the buffering effect. Salivary mucoid and bacteria have an insignificant buffer action in whole saliva. In resting saliva, the buffering effect is decreased because of the smaller concentration of bicarbonate in resting saliva than in activated saliva; therefore, phosphate becomes relatively more important. Salivary sediment and plaue have different buffering systems. The former has a variable amount of adsorbed bicarbonate which plaque does not possess. 2. 2. The effect of eating a meal on the buffering power of the saliva of fifteen subjects was examined. A constant increase or decrease in buffering after the meal was not observed. 3. 3. Paraffin-activated saliva, collected during a period similar to that taken for the meal, did not show any appreciable changes in buffering properties, as determined by comparison of the first and last five-minute samples of saliva. During the test period, however, changes were observed which were paralleled by changes in bicarbonate concentration. No consistent relation was found between HCO ′ 3, Na +, and K + concetrations and volume of sample. 4. 4. A significant relation was observed between buffering effect for the sample, pH 7.0 to 6.0, and the volume of five-minute samples of activated saliva for a group of sixty-seven subjects. 5. 5. The limitations of the buffering test in attempting to assess caries susceptibility were investigated in a group of sixty-five subjects.
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Feb 1, 1957
R.S Manly + 1
