THE EFFECT OF THE CONCENTRATION OF D-GLUCOSE ON THE ATTACK OF TOOTH SUBSTANCES IN THE ARTIFICIAL MOUTH

¹ University of Alabama, Dental School and Medical College, Departments of Biochemistry and Bacteriology, Birmingham, Ala.

Under the "standard" conditions for the operation of the artificial mouth, it is demonstrated that the attack at relatively high glucose concentrations (0.5 per cent) is mainly decalcification, whereas at glucose concentrations of 0.25 per cent and less, previously decalcified dentin is softened, pigmented, and, finally, completely destroyed. When the glucose concentration is about 0.25 per cent, both decalcification and dentinal matrix destruction occur fairly rapidly; the dentin, enamel, and cementum of sound teeth are extensively destroyed in a period of several months.

A method was developed for determining the relative numbers of streptococci and lactobacilli associated with a single tooth. It was shown that the streptococci were present at all the glucose concentrations studied, but seemed to reach a maximum at about 0.25 per cent glucose. Lactobacilli required the presence of a minimum of about 0.25 per cent glucose for survival. A preliminary qualitative study was also made of the organisms found in the plaque when the medium contained 0.01 per cent sodium thioglycollate and variable amounts of glucose.