ABSTRACT
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.
Subject(s)
Dental Enamel/anatomy & histology , Dental Plaque/physiopathology , Sorbitol/pharmacology , Sucrose/pharmacology , Xylitol/pharmacology , Animals , Cattle , Dental Caries/etiology , Dental Caries/physiopathology , Dental Caries Activity Tests , Dental Enamel/drug effects , Hardness , Humans , Hydrogen-Ion Concentration , Models, BiologicalABSTRACT
Specific pathogen-free rats infected with Streptococcus mutans PS-14 (serotype c) and fed a cariogenic diet containing 380 parts/10(6) of bacteriocin, purified from Strep. mutans C3603, developed significantly fewer carious lesions than controls infected with Strep. mutans and fed the same diet without bacteriocin. The caries-inhibitory effect was 58.7 per cent. Oral appliances fixed with bovine enamel slabs were worn by volunteers to test bacteriocin C3603. The enamel slabs were treated with 500 parts/10(6) bacteriocin in 3 per cent sucrose solution for 10 min, 4 times daily, or with 3 per cent sucrose solution, 3 times daily, for 10 min and just before bedtime with 500 parts/10(6) bacteriocin once for 1 min. The bacteriocin exerted a strong inhibition of cariogenicity of sucrose.
