Influence of Er,Cr:YSGG laser, associated or not to desensitizing agents, in the prevention of acid erosion in bovine root dentin.

This in vitro study evaluated the influence of the Er,Cr:YSGG laser, associated or not to desensitizing agents, in the prevention of acid erosion in bovine root dentin. Eighty dentin specimens were selected and divided into eight groups (n = 10): G1: negative control; G2: positive control (5% fluoride varnish-FV); G3: Er,Cr:YSGG laser; G4: FV + laser; G5: 3% potassium oxalate; G6: 3% potassium oxalate + laser; G7: biphasic calcium silicate/phosphate gel (gel); G8: gel + laser. Laser parameters: 0.5 W, 6.25 J/cm(2) at 1-mm distance. The erosive drink used was a cola soft-drink (pH = 2.42 at 4 degrees C), lasting 5 min, twice a day, with 6-h intervals between the challenges, during 14 days. Kolmogorov-Smirnov and Levene's tests were satisfied. The surface roughness data were submitted to ANOVA and Tukey post hoc tests. For the wear profile, Kruskal-Wallis and Dunn post hoc tests were used. Afterwards, the Spearman correlation test was performed. All statistical tests assumed a significance level of 5% (alpha = 0.05). G1 presented the highest surface roughness value after the erosive challenge (3.586 mum(2) +/- 0.205 mum(2)) and the G7 presented the lowest surface roughness value after the erosive challenge (1.071 mum(2) +/- 0.180 mum(2)). For the lost volume, G4 presented the lowest percentage (9.7% +/- 0.9%), while G1 had the highest percentage (41.8% +/- 2.5%), both with p < 0.05. There was a weak correlation between the response variables (rho = 0.33). All groups presented lower values of surface roughness and loss of volume when compared to the negative control group. For the surface roughness, the biphasic calcium silicate/phosphate gel presented the best result. For volume loss, the 5% fluoride varnish + Er,Cr:YSGG laser showed the best results compared to the other groups.