Effect of Fluoride Concentration on Reduction of Enamel Demineralization According to the Cariogenic Challenge

Abstract

Fluoride present in toothpaste at 1,100 µg/g is considered effective on caries control. However, under high cariogenic challenge due to increasing sugar exposure, higher fluoride concentration (5,000 µg/g) could be necessary to compensate the unbalance on caries process. This was tested in a pH-cycling regimen, which evaluated the effect of fluoride concentration relative to toothpaste on reduction of enamel demineralization under conditions of two levels of cariogenic challenge. Enamel slabs (n=20) were subjected to two pH-cycling regimens, simulating 8x and 16x/day sugar exposure and were treated with solutions containing: 0 (no fluoride), 275 or 1,250 µg F/mL, resulting in 6 treatment groups: 4-h/0-F; 8-h/0-F; 4-h/275-F; 8-h/275-F; 4-h/1,250-F and 8-h/1,250-F. The 275 and 1,250 µg F/mL concentrations simulate mouth salivary dilution when 1,100 and 5,000 µg/g toothpastes are used. Enamel demineralization was assessed by surface (%SHL) and cross-sectional hardness. Fluoride taken up by enamel was also evaluated. Data were analyzed by ANOVA one-way and Tukey's test. The treatment with 1,250 µg F/mL significantly reduced %SHL compared with 275 µg F/mL (p<0.05), irrespective the level of cariogenic challenge (4-h/1,250-F vs. 4-h/275-F and 8-h/1,250-F vs 8-h/275-F comparisons, respectively). These data were supported by fluoride concentration found in enamel. These findings suggest that higher fluoride concentrations could partly compensate the greater caries risk under higher cariogenic challenge due to increasing sugar exposure.

In Vitro Evaluation of Fluoride in Saliva After Topical Application of Professional Use Products

“…Studies corroborate that low fluoride concentrations, i.e. 0.1-1 ppm [20], present continuously in buccal fluids (saliva and biofilm liquid) interfere negatively with the cariogenic process, being able to reduce demineralization and increase remineralization of dental enamel [2,3,13,20]. One study observed that above 135 ppm of fluoride there is no additional significant decrease in tooth enamel demineralization.…”

“…Oral hygiene performed regularly with conventional fluoride dentifrice (1000/1450/1500 ppm F-) and appropriate brushing technique is sufficient to maintain good oral conditions [11][12][13]. However, individuals with a high risk of caries (active caries, high sugar consumption and increased retention of biofilm by the use of orthodontic appliance) require additional methods to increase the intra-oral fluoride concentration in order to reduce their risk.…”

“…However, individuals with a high risk of caries (active caries, high sugar consumption and increased retention of biofilm by the use of orthodontic appliance) require additional methods to increase the intra-oral fluoride concentration in order to reduce their risk. Alternatives can be found in the form of solution, gel or varnish [2,[12][13][14].…”

Effects of Fluoride on Two Chemical Models of Enamel Demineralization

“…The physical and mechanical properties of the artificial lesions might be different if the concentration of the fluoride changed [ 23 ]. Other conditions such as the use of deciduous or permanent teeth might also affect the result.…”

Fluoride content in children’s dentifrices marketed in Lima, Peru

“…2 The anticaries effect of fluoride toothpastes, together with the correct toothbrushing technique, promotes the disruption of biofilm, and maintains the demineralization-remineralization balance. 3 An amount of 1000 ppm of F in toothpaste achieves this benefit, but the F must be in soluble form (SF) for it to be active in its formulation, and thus be able to interfere in the development of a disease. 1,4,5,6,7,8 The presence of SF in a dentifrice depends on its formulation, in terms of type of fluoride salt and abrasive used.…”