EFFICACY OF CHLORHEXIDINE SOLUTION WITH FLUORIDE VARNISHING IN PREVENTING ENAMEL SOFTENING BY STREPTOCOCCUS-MUTANS IN AN ARTIFICIAL MOUTH

For study of the enamel-protective effect of chlorhexidine-fluoride ap plications, the labial surfaces of pieces of bovine incisors were trea ted with 0.2% chlorhexidine gluconate solution, with Duraphat fluoride varnish, or with both of the above agents, while one group was treate d with distilled water and one was left as an untreated control. Furth ermore, a placebo varnish was used in the chlorhexidine- and distilled -water-treated groups; all the varnishes were removed after 24 h. The enamel slabs were mounted pairwise in an artificial mouth to form appr oximal contacts. The teeth were continuously rinsed with a common pool of artificial saliva to which was added 3% sucrose, and which was inf ected on the first day with Streptococcus mutans, ''Ingbritt''. The sa liva was renewed daily and the incubation at 37 degrees C lasted for 1 0 days. The appreciable softening found in the distilled-water- and pl acebo-varnish-treated group tended to be prevented by the chlorhexidin e and even more by the fluoride treatment, while the chlorhexidine-flu oride treatment prevented enamel softening completely. The saliva, inf ected only on the first day, and renewed daily, tended to become more acidified toward the end of the experimental period, obviously because the fermenting organisms had infected the surfaces of the model and f ormed plaque-like coatings on the enamel.