Mechanism of Fluoride Dentifrice Effect on Enamel Demineralization

Abstract

Although the anticaries effect of fluoride (F) dentifrices is clearly established, the relative importance of F taken up by dental plaque not removed by brushing and of F products (CaF₂-like) formed on totally cleaned enamel for the subsequent inhibition of demineralization is not known. Both effects were evaluated using conventional (1,100 μg F/g) and low-F concentration (500 μg F/g) dentifrices in a randomized, crossover, double-blind in situ study. Enamel blocks not treated or pretreated with the dentifrices to form CaF₂-like deposits were mounted in palatal appliances in contact with a Streptococcus mutans test plaque. Volunteers brushed with non-F (negative control), low-F or conventional dentifrices and inserted the appliance in the mouth. F concentration in the fluid and solid phases of the test plaque was determined after 30 min, and a rinse with 20% sucrose solution was performed. After additional 45 min, plaque was collected and the loss of surface hardness at different test-plaque depths was measured. CaF₂-like deposition on enamel and F taken up by plaque due to the use of F dentifrices were able to significantly increase F concentration in the fluid phase of the test plaque, but only the latter significantly reduced the loss of hardness because of the 20–30 times higher F concentration. Also, significant differences between the low-F and conventional dentifrices were observed for F on enamel, in plaque and on the subsequent loss of hardness. The results suggest that uptake of F by dental plaque not removed by brushing may be the main cause of the anticaries effect of F dentifrices.

Fluoride: its role in dentistry

“…23,24 It has recently been shown that the enrichment of remnants of plaque not removed by brushing with fluoride from toothpastes is primarily responsible for its anticaries effect. 25 This means that brushing with fluoride toothpastes is able to protect not only the cleaned surfaces (from which the biofilm was removed), but also the surfaces the toothbrush did not reach. This idea may explain why brushing with a non-fluoride toothpaste, although effective in controlling periodontal inflammation, is not able to significantly reduce caries; to do this, the toothpaste must have fluoride.…”

Influence of the Curing Mode on Fluoride Ion Release of Self-adhesive Resin Luting Cements in Water or During pH-Cycling Regimen

“…Such benefits are due to its ability to inhibit the demineralization and enhance remineralization. [3][4][5] A number of studies have suggested that the fluoride released from glass ionomer cements can reduce the demineralization of the surrounding dentin or enamel and favor the remineralization of lesions close to the restoration wall. [6][7][8][9] Glass ionomer cements contain calcium fluoroaluminosilicate glass, which is attacked by polyacids to release cations and fluoride ions.…”

Timing of fluoride toothpaste use and enamel-dentin demineralization

“…1,2,3 However, the extent to which each of these effects influences caries development is unknown, because they are difficult to isolate. Although F toothpaste is able to provide F ions to the oral cavity to interfere with both phenomena, 4,5 its effect when used before or after demineralizing challenges has only been studied in vitro. 1 In this in vitro study, 1 no difference was observed between F toothpaste used to inhibit the demineralization process or to enhance the mineral repair that occurs during the subsequent remineralization.…”