Surface roughness of fluoride-releasing restorative materials after topical fluoride application

The aim of this study was to assess the effect of a single application of two topical fluoride agents: NNaF and APF (2% neutral sodium fluoride gel and 1.23% acidulated phosphate fluoride gel, respectively) on the surface roughness (Ra) of Fuji IX GP, Ketac N100, Vitremer, Dyract AP, Compoglass F and Filtek Ultimate.

The effect of NNaF and APF on the surface roughness of fluoride-releasing restorative materials was tested on disk-shaped material specimens with a surface profilometer.

All materials were handled according to manufacturer's instructions. ISO standardised specimens were prepared for each material and then stored in distilled water for 24 hr. Each sample was polished with 600 and 1200 grit sandpaper on both sides while keeping the material surface wet. Ra measurements were performed on untreated specimens initially and after 1 min, 4 min and simulated 2-years for both fluoride applications, respectively. The mean Ra values for all specimens were measured using a surface profilometer.

Differences in surface roughness values were assessed using paired t-test. The differences between the experimental groups were analysed with one-way ANOVA; p<0.05 was accepted as statistically significant.

The results of the present study indicated that Ra values for Fuji IX GP and Vitremer increased significantly after all APF, but not NNaF applications. All tested materials exhibited increased Ra values for both treatment regimes, but this was not found statistically significant.

APF gel application significantly increased the surface roughness of both Fuji IX GP and Vitremer for all time periods.