Enamel microhardness change and plaque pH measurements in an intra-oral model in humans.
Changes in plaque pH and microhardness of bovine enamel slabs were evaluated with a seven-day intra-oral cariogenicity test (ICT). The test enamel slabs were mounted in prosthetic appliances with a Dacron mesh cover for enhancement of microbial colonization. Three percent solutions of sucrose, sorbitol, and xylitol were evaluated as four daily extra-oral immersions of 10 min each, for seven days, and the results were compared with baseline experiments (no daily immersions). The pH was measured with antimony electrodes on one-day and seven-day ICT plaque samples that were challenged with a one-minute immersion in the studied substrates. Plaque samples in the baseline experiments were challenged with 3% sucrose. The enamel softening was assessed with measurements of microhardness. Sucrose challenge caused pH depression with both the baseline and the sucrose-immersed plaque. Sorbitol and xylitol challenge did not depress the plaque pH. Compared with the baseline, sucrose immersions caused enamel softening; sorbitol and xylitol did not.
D000818:Animals; D002417:Cattle; D003731:Dental Caries / Q000209:etiology / Q000503:physiopathology; D003732:Dental Caries Activity Tests; D003743:Dental Enamel / Q000033:anatomy & histology* / Q000187:drug effects; D003773:Dental Plaque / Q000503:physiopathology*; D006244:Hardness; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008954:Models, Biological; D013012:Sorbitol / Q000494:pharmacology*; D013395:Sucrose / Q000494:pharmacology*; D014993:Xylitol / Q000494:pharmacology*
D013012:Sorbitol; D013395:Sucrose; D014993:Xylitol