Abstract
Dental literature contains many references to the deleterious effects of acids in the saliva, especially after ingestion of excessive amounts of carbohydrate. Those who believe that caries is a process which begins primarily on the external part of the tooth structure and extends inward, stress the solvent action of acids in saliva upon tooth enamel, (largely inorganic) and, subsequently upon the inorganic constituents of the dentine.
Since the reaction of saliva obtained immediately after expectoration as well as that obtained by cannulation is only slightly acid, pH6.6, 1 , 2 the combined secretions and excretions of the salivary glands possess too low a concentration of hydrogen-ions to have even the slightest solvent action upon the tooth structure. However, to the actual secretions and excretions of the salivary glands we must add “mouth sweepings,” comprising the desquamated cells, food particles, dead bacteria, etc., together with a large variety of living micro-organisms. The importance of the type of food residues, etc., in relation to the predominant micro-organisms in the oral cavity, and, the reaction of the saliva has been emphasized by Bunting. 3
During the last three years we have been studying the inorganic constituents of the saliva. It seemed desirable to carry out experiments to determine the extreme variations in the reaction that could be brought about by various organisms and with various types of food residues.
METHODS.
Samples of Resting Saliva collected from 3 to 4 adults were combined, and, after removing a small portion for the controls, the main portion was sterilized in Erlenmeyer flasks by autoclaving at 20 pounds pressure for 15 minutes. Except for B. acidophilus, the organisms used were obtained by aspiration from the gingival tissues of human subjects.
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