Effect of APF gel application time on enamel demineralization and fluoride uptake in situ

Abstract

This in situ crossover and blind study was conducted to investigate the effect of professional acidulated phosphate fluoride (APF) gel application time on the subsequent inhibition of enamel demineralization. During 3 phases of 28 days each, 15 volunteers wore palatal appliances containing 4 enamel blocks, which were subjected to 3 treatment groups: not treated (control) and pre-treated with APF gel for 1 or 4 min. Dental plaque was allowed to accumulate on the blocks and the appliances were immersed in 10% sucrose solution 3 times a day simulating a cariogenic challenge. After each phase, the blocks were removed to evaluate enamel demineralization and concentration of fluoride (F) remaining after the cariogenic challenge. F formed on enamel was determined in additional enamel blocks subjected only to APF gel application. APF gel was efficient in reducing enamel demineralization (p<0.05), irrespective of the application time (p>0.05). Also, the concentration of the F formed and retained on enamel was significantly higher after APF gel application (p<0.05), but the effect of time of application was not statistically significant (p>0.05). The results suggest that APF application for either 1 or 4 min is equally efficient to increase F concentration in enamel and reduce enamel demineralization.

Effect of Acidulated Phosphate Fluoride Gel Application Time on Enamel Demineralization of Deciduous and Permanent Teeth

“…At the beginning of each phase, the appliances contained five deciduous and five permanent enamel slabs. Immediately after the application, one deciduous and one permanent slab placed at the anterior part of the appliance [Villena et al, 2009] were removed for determination of CaF 2 -like material and fluorapatite (FAp) formed.…”

“…For the statistical analysis, the volunteer was considered as an experimental block (n = 16). The sample size was determined on the basis of our previous findings using the same experimental protocol [Paes Leme et al, 2004;Villena et al, 2009;Vale et al, 2011] with a statistical power higher than 90% for the variable demineralization. This study was blind only with respect to the examiners, who analyzed previously coded samples to ensure blindness.…”

“…The findings suggest that 1 min of APF gel application provides a similar effect on inhibition of demineralization as 4 min, for both permanent and deciduous enamel. Copyright © 2012 S. Karger AG, Basel There is clear evidence of the caries-inhibiting effect of fluoride gels [Marinho et al, 2002], but the relevance of the recommended pre-and postapplication procedures has been questioned [Delbem et al, 2005;Villena et al, 2009]. Among these clinical procedures, the application time of professional acidulated phosphate fluoride gel (APF gel) has been studied in vitro and in situ and a shorter time would be desirable considering the acute…”

“…Using an in situ model that has been widely used to study different aspects of the caries process [Paes Leme et al, 2006], no statistically significant difference between APF gel application for 1 versus 4 min was shown, either on fluoride uptake and its retention, or on reduction of demineralization [Villena et al, 2009]. However, in this study the permanent enamel slabs were exposed to sucrose at a frequency of three times a day, and it is possible that under a higher frequency [Cury et al, 2010] a longer application time could be necessary.…”

Insoluble NaF in Duraphat® May Prolong Fluoride Reactivity of Varnish Retained on Dental Surfaces

“…Their mechanism of action is attributed to the reactivity of the fluoride present in these formulations with enamel/ dentine, forming loosely-bound, calcium fluoride (CaF 2 )-like reservoirs (3), whose effect on enamel demineralization is concentration-dependent (4). However, while in gels all fluoride is available for an immediate (1-4 min) reaction with enamel/dentine because the NaF salt used is dissolved in water (5,6), in the varnish the colophony hydrophobic matrix is dissolved in ethanol, in which only a small percentage of NaF is soluble.…”