Effect of fluoride varnish and gel on dental erosion in primary and permanent teeth

Abstract 

Objective

To assess the effect of a fluoride varnish and gel on the erosive wear of primary and permanent teeth.

Design

Sixty human primary (n=30) and permanent (n=30) enamel specimens were randomly assigned to one of the following groups: APF gel (1.23% F), NaF varnish (2.26% F), and control (no treatment). Fluoride gel was applied for 4min and fluoride varnish for 24h. Six daily demineralisation–remineralization cycles of 5min of immersion in a cola drink (pH 2.3) and 30min in artificial saliva were conducted during 7 days. All specimens were stored in artificial saliva between and after cycles. Surface Knoop microhardness (%SMHC) readings were performed at baseline, 48h and 7 days. Data were tested using ANOVA and Tukey's tests (p<0.05).

Results

For primary enamel, the mean %SMHC (±SD) after 48h and 7 days was, respectively: gel (31.0±14.4 and 36.9±7.5), varnish (26.7±9.5 and 38.3±8.7), and control (35.8±8.6 and 45.0±8.6). For permanent enamel, such values were: gel (37.5±7.7 and 27.8±7.5), varnish (31.7±9.6 and 27.4±11.1) and control (48.6±6.4 and 43.1±6.4). In primary enamel, erosion inhibition by fluoride was not significant at 48h (p=0.203) and 7 days (p=0.082). In permanent specimens, both products showed a significant effect (p<0.001).

Conclusions

Both fluoride varnish and gel were able to inhibit erosive enamel loss but mainly in the permanent experimental groups. Primary and permanent enamel substrates reacted differently to both demineralization by a cola drink and remineralization by fluoridated compounds.

Keywords: Erosion prevention, Fluoride, Microhardness, Primary teeth, Permanent teeth