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The aim of the present study was to study the effect of fluoride gel treatment on fluoride release and inhibition of acid production of Streptococcus mutans by different glass ionomer cements. Test slabs of four glass ionomer materials were fitted into the bottom of a test tube. A layer of S. mutans cells was centrifuged onto the test slabs, and the specimens were incubated for 4 h in 1.7% sucrose solution. Incubations were made using fresh, aged (29 d), aged and F-treated (1.25% F-gel), and aged, F-treated and aged samples (n=15 per group). After each incubation, pH and F contents of the fluid phase were determined. The freshly mixed glass ionomer samples released large amounts of fluoride, and the pH fall in the fluid phase was significantly inhibited. For aged samples, the fluoride release decreased strongly and no inhibitory effect on acid production by S. mutans was seen. After application of fluoride gel, fluoride release and inhibitory effect were significantly higher than initially for all glass ionomer cements. In conclusion, all glass ionomer cements were able to take up fluoride and subsequently release it, which resulted in reestablishment of their antibacterial effect. The patterns of fluoride release and antibacterial action were virtually the same for conventional and resin-reinforced glass ionomer cements. [ABSTRACT FROM AUTHOR]

All currently used topical fluoride agents deposit soluble fluoride as calcium fluoride on enamel or in lesions. Calcium fluoride serves as a source of fluoride for the formation of fluorapatite. The latter phase is formed when pH drops in plaque, not during topical application. The potential for calcium fluoride formation should probably be increased in topical fluoride agents. In countries with low caries prevalence, the clinical recommendations for topical fluoride need to be reconsidered. Toothpaste is the basic fluoride regimen recommended for everybody. The need for additional fluoride supplementation depends on caries activity. There is no distinct difference in the caries-preventive effects of concentrated fluoride solutions, gels, or varnishes. Thus, the choice of method depends on costs, convenience, patient acceptance, and safety. The use of fluoride varnishes has proven to be a feasible and safe method of fluoride application. With fluoride varnishes, the amounts of fluoride exposure can be better controlled, and less chair-time is required compared with conventional solutions and gels. No dose-response effect to concentrated fluoride agents is apparent, and the benefit of frequent application is not clearly established. In individuals with the most severe cariogenic challenge, combinations of fluoride and antimicrobials may give better clinical effects than fluoride alone. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate whether the release of fluoride and the antimicrobial effect of freshly mixed glass ionomers could be prolonged by application of fluoride on aged material. Test slabs of freshly mixed and aged (14 d in water) conventional and silver glass ionomer (Ketac-Fil and Ketac-Silver, Espe, Seefeld, Germany) and composite (Silux Plus, 3M, St. Paul, MN) were fitted into the bottom of a test tube. A layer of S. mutans Ingbritt cells was centrifuged onto the test slabs, and the samples were incubated for 20 h in 1.7% sucrose solution. After the incubation, pH, F, and Ca contents of the fluid phase, and F, Mg, P, and K contents of the cells were determined. The aged glass-ionomer samples were then covered with toothpaste (0.1% F) or with fluoride gel (1.25% F), and the composite samples with fluoride gel. After being thoroughly rinsed, S. mutans cells were incubated on the samples as above. The pH fall was significantly inhibited by freshly mixed glass ionomers, and there were changes in cellular cation and phosphorus contents. Large amounts of fluoride were found in the fluid and cells. For old glass ionomers, no inhibitory effect on pH fall could be seen. Fluoride release had decreased to a low level. Application of fluoride toothpaste on the material resulted in a small increase in the release of fluoride and slight inhibitory effects on bacteria. After application of fluoride gel, the fluoride contents of the fluid phase and cells were as high as in freshly mixed samples, and the inhibitory effect on pH fall and electrolyte metabolism was even more pronounced than initially. Fluoride release from old glass ionomers and their antimicrobial effect could be significantly increased by application of fluoride gel on the material. [ABSTRACT FROM AUTHOR]

Molar teeth of four groups of Osborne-Mendel rats, kept on a cariogenic dict, were treated once per day for 48 days with either distilled water (solution C), a solution containing 0.05% chlorhexidine gluconate and 0.04% NaF, pH 5.8 (solution CXF), CXF plus 1000 ppm Sr (solution CXFS), or CXFS plus 1000 ppm Zn (solution CXFSZ). Caries of the hemi-sectioned lower molars was scored according to grades of severity, and the extent of the buccal plaque was estimated. Inflammatory cell infiltration, vascularity, and thickness of the oral mucosa were estimated from stained sections of the buccal oral mucosa to detect possible adverse effects of the treatments. Fissure caries lesions with involvement of the dentin were reduced by 57% (p < 0.01) with the CXF treatment and by 68%o (p < 0.001) with the CXFS treatment. The CXFSZ treatment reduced the fissure caries least (44%, p < 0.05), but it appreciably reduced the extent of plaque. The mucosal changes were greatest in the group receiving the CXFSZ treatment, but they were generally small and at a non-pathological level. Supplementation of the CXF solution with Sr thus appeared beneficial for caries reduction. [ABSTRACT FROM AUTHOR]