A ROLE OF GLUCOSE IN THE PRODUCTION OF ARTIFICIAL CARIES

¹ Harvard School of Dental Medicine, Boston, Mass.

1. When human, intact teeth are incubated in a medium consisting primarily of known chemical substances including glucose and inoculated with a mixed oral flora, a pigmented, carious change develops on the exposed enamel surface and involves the underlying dentin. There is demineralization of the exposed enamel, however, surface continuity with the underlying destroyed dentin is maintained. This carious area is somewhat softer than that seen in human caries and probably resembles the acute type of caries. Microscopically, however, it resembles the changes occurring in the dentin and enamel in human in vivo caries. The chemical changes observed during incubation are the formation of lactic acid and calcium. Deamination of the amino acids in the medium appears to be inhibited.

2. When intact teeth are incubated in this inoculated medium without glucose there is no change observed on the exposed tooth surface. There is no calcium formed in the medium. Rapid deamination of the amino acids occurs and the medium becomes alkaline.

3. When intact teeth are incubated in this inoculated medium without glucose, but buffered at a pH 4.0, the exposed tooth surface becomes rapidly decalcified and except for the complete loss of enamel the change does not resemble natural caries. Calcium is formed and inhibition of deamination is again observed.

4. When intact teeth are incubated in this medium with glucose but buffered at a pH of 8.0 there is no change observed on the exposed tooth surface. There is no calcium formed and rapid deamination is observed.

5. In the above experiments glucose not only provides a substrate for acid formation thus producing a H-ion concentration suitable for decalcification of enamel, but also it appears to serve an entirely different role in that only when glucose is present in the medium are we able to produce the pigmented carious-like lesion involving the enamel and dentin.