Effects of a sodium fluoride solution and a varnish with different fluoride concentrations on enamel remineralization in vitro

Abstract

– To study the efficacy of sodium fluoride varnishes and a NaF solution in remineralization of enamel, 120 slabs of non‐carious human enamel enamel were presoftened for 6 h and randomly divided into six groups. The slabs were stored in synthetic saliva for 9 days, except for a daily 30‐min immersion in 0.1 M lactic acid‐NaOH buffer. During the 9‐day period, one group of the slabs received no treatment, and the rest were treated once or three times with 2.3% or 1.1% sodium fluoride varnish Duraphat, or nine times with a 0.1% NaF solution. Finally, the slabs were demineralized for 1 h, and the amount of dissolved Ca and F was determined. Microhardness of enamel was determined initially, after presoftening, after the 9‐ day period, and after the 1‐h demineralization. All fluoride treatments prevented enamel softening almost completely during the 9 days, but the control slabs softened markedly. Fluoride varnishes were more effective than NaF solution. Three applications of 2.3% Duraphat were slightly more effective than any of the other varnish treatments, but one treatment with 2.3% varnish was not more effective than treatments with 1.1% varnish. Enamel treated three times with 1.1% varnish showed the greatest acid resistance during the 1‐h demineralization. The results suggest that the efficacy of the varnish was not proportional to the fluoride concentration but rather to the number of applications. Fluoride uptake by enamel was greatest with the most concentrated varnish. Enamel solubility was not, however, directly proportional to the fluoride content of enamel.

Effect of Nd:YAG Irradiation and Fluoride Application on Dentine Resistance to Erosionin Vitro

“…However, the efficacy of fluoride varnishes and gels in decreasing demineralization and enhancing remineralization of dental hard tissues is similar. 22,23 On the other hand, the protective effects of laser irradiation of enamel and dentine from demineralization have gained increasing attention in recent years. Several types of lasers, such as ruby, CO 2 , Nd:YAG, and argon, with different operational modes and energy outputs have been investigated.…”

Prevention of Rat Fissure Caries by Sodium Fluoride Varnish (Duraphat®) with Different Fluoride Concentrations

“…This is somewhat surprising, since a si lane fluoride varnish (Fluor Protector®) with approxi mately the same fluoride concentration (0.7%) has been found effective in caries prevention in some clin ical studies [Salem et al, 1979;Clark et al, 1985], and even much lower concentrations have inhibited en amel dissolution in vitro and in vivo [De Bruyn et al, 1986, 1988. The difference may be explained by dif ferent physicochemical properties of the two types of varnishes [De Bruyn and Arends, 1987, a review].…”

“…In several studies, the effect of a fluoride regimen in caries prevention or de-and remineralisation of en amel has not been directly proportional to the fluo ride content of the preparation [ten Cate and Simons, 1986, De Bruyn et al, 1986, 1988Goorhuis and Purdell-Lewis, 1986;Ripa et al, 1988]. Based on this, the fluoride concentrations of some professionally ap plied topical fluorides seem unnecessarily high.…”

Inhibition of Secondary Caries Lesion Progression Using Fluoride Varnish

“…The result is loss of at least part of the loosely bound fluoride important for remineralization. In this study we decided to enhance the remineralization potential of the varnishes by not rinsing, like other authors [Seppä, 1988;Scholtanus et al, 1986]. If FV enhances the formation of a layer of soluble fluoride, mainly CaF 2 -like deposits on enamel [Nelson et al, 1983], this slowly dissolving material is an important source of fluoride for enhancement of remineralization and uptake in the outer enamel over a long time period.…”

“…Attin et al [1997] used a Duraphat varnish to successfully enhance remineralization of bleached enamel specimens. Seppä [1988] suggested that the benefits of FV are related more to their ability to enhance remineralization of primary caries than to increase the fluoride content of the surface. Her results suggest that the efficacy of the varnishes was not proportional to their fluoride concentration but rather to the number of applications.…”