Effects of Er:YAG Laser Irradiation and Topical Fluoride Application on Inhibition of Enamel Demineralization

Objective: The aim of this study was to evaluate the effect of the Er:YAG laser and acidulated phosphate fluoride application on enamel solubility around orthodontic brackets via atomic absorption spectrometry. Materials and Methods: Twenty freshly extracted upper premolar teeth were divided into 2 halves. Each half was covered with a nail varnish, excluding 1 mm (width) of space around each side of the bracket base. Orthodontic brackets were bonded in the center of the isolated area. Four groups were generated. The first group was the control group, and no treatment was performed. In group II (F), only fluoride was applied. Groups III and IV were laser and fluoride combination groups. In Group III (LF), fluoride was applied to the laser-irradiated surface, whereas laser irradiation was performed on the fluoridated enamel surface in Group IV (FL group). Afterwards, samples were demineralized in an acidic solution for 96 hours, and calcium assessment was performed using atomic absorption spectrometry. Comparisons of the calcium ion release values of the groups were performed with Kruskal-Wallis and Tukey honestly significant difference post hoc tests. The statistical significance level was set at p < 0.05. Results: The least amount of calcium release was observed in the LF group (median, 112.7 ppm), while the parameter of the control group was the highest (median, 217.9 ppm). The differences between the control and F groups, control and LF groups, and LF and FL groups were statistically significant. No difference was recorded between the control and FL groups. Conclusion: Laser treatment followed by topical application of acidulated phosphate fluoride gel resulted in the lowest calcium dissolution from the enamel surface.