Abstract
Considering the positive effects of high power lasers in preventing dental caries and the promising results regarding the reduction of enamel erosion, the purpose of this in vitro study is to evaluate the potential of a CO2 laser (9,3 µm) - associated or not with stannous fluoride or titanium tetrafluoride - in controlling erosion in dental enamel. Ninety slabs of human enamel will be selected and, after erosive-like lesion formation, randomly divided into 09 surface treatment groups (n=10): G1 - negative control (no treatment); G2 - AmF/NaF/SnCl2 solution (pH 4.5); G3 - 4% TiF4 gel (pH 1.5); G4 - CO2 laser (9,3 µm) (P1); G5 - CO2 laser (9,3 µm) (P1) + AmF/NaF/SnCl2 solution; G6 - CO2 laser (9,3 µm) (P1) + 4% TiF4 gel; G7 - CO2 laser (9,3 µm) (P2); G8 - CO2 laser (9,3 µm) (P2) + AmF/NaF/SnCl2 solution and G9 - CO2 laser (9,3 µm) (P2) + 4% TiF4 gel. Samples will be subjected to 10 days of erosive cycling through alternate immersions in solutions of citric acid (1%, pH 2.3, 2 minutes, 6x/day) and remineralizing solution. Two CO2 irradiation parameters (9.3 µm) will be tested (P1 and P2), followed by active application of 20 µl TiF4 gel for 4 minutes or daily immersions in 05 ml of AmF/NaF/SnCl2 solution for 2 minutes. After erosive-like lesions formation, immediately after surface treatments, after 05 days of erosive cycling and at the end of the 10 days of erosive cycling, the superficial tissue loss will be determined by non-contact optical profilometry (µm). After profilometry, 27 samples (n=3) submitted to 10 days erosive cycling and 27 extras samples (n=3) submitted to surface treatments only will be evaluated qualitatively by scanning electron microscopy. The optical profilometry results will be subjected to homogeneity and normality tests to determine the most appropriate statistical test (± = 5%)
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