Effect of a Single Application of TiF4 and NaF Varnishes and Solutions Combined with Nd:YAG Laser Irradiation on Enamel Erosion in Vitro

Abstract

This in vitro study aimed to analyze the influence of neodymium-doped yttrium aluminum garnet (Nd:YAG) laser irradiation on the efficacy of titanium tetrafluoride (TiF(4)) and sodium fluoride (NaF) varnishes and solutions to protect enamel against erosion. The effect of Nd:YAG laser irradiation on NaF and AmF was analyzed; however, there is no available data on the interaction between Nd:YAG laser irradiation and TiF(4). Bovine enamel specimens were pre-treated with NaF varnish, TiF(4) varnish, NaF solution, TiF(4) solution, placebo varnish, Nd:YAG (84.9 J/cm(2)), Nd:YAG prior to or through NaF varnish, Nd:YAG prior to or through TiF(4) varnish, Nd:YAG prior to or through NaF solution, Nd:YAG prior to or through TiF(4) solution, and Nd:YAG prior to or through placebo varnish. Controls remained untreated. Ten specimens in each group were then subjected to an erosive demineralization (Sprite Zero, 4 × 90 s/day) and remineralization (artificial saliva, between the erosive cycles) cycling for 5 days. Enamel loss was measured profilometrically (μm). Additionally, treated but non-eroded specimens were additionally analyzed by scanning electron microscope (SEM) (each group n = 2). The data were statistically analyzed by ANOVA and Tukey's post-hoc test (p < 0.05). Only TiF(4) varnish (1.8 ± 0.6 μm), laser prior to TiF(4) varnish (1.7 ± 0.3 μm) and laser prior to TiF(4) solution (1.4 ± 0.3 μm) significantly reduced enamel erosion compared to the control (4.1 ± 0.6 μm). SEM pictures showed that specimens treated with TiF(4) varnish presented a surface coating. Nd:YAG laser irradiation was not effective against enamel erosion and it did not have any influence on the efficacy of F, except for TiF(4) solution. On the other hand, TiF(4) varnish protected against enamel erosion, without the influence of laser irradiation.