Prevention of Enamel Erosion With Fluoride Application and Nd:YAG Laser

Objectives: This “in vitro” study is to examine the effects with Nd: YAG laser with or without of fluoride topical application in erosion preventing in bovine enamel.
Methods: Sixty bovine enamel blocks were selected, planned, polished and randomly divided into four groups: G1- acidulated phosphate fluoride (APF) 1.25%, 1 min; G2- Nd: YAG Laser (0,6W, 60mJ,10 Hz, 10s) ( charcoal paste); G3- L + F , G4 - F + L. Then, were immersed in solution citric acid 1% for 3 minutes, the samples were washed with distilled water (30 s), and stored in mineral solution ( pH 7,0 for 24h). The evaluation of Knoop microhardness of the enamel surface was performed, before and after treatment and after erosive challenge (3 indentations). The percentage obtained from the mineral concentration and change of microhardness (%SMHC).
Results: The data were subjected to statistical analysis ANOVA and Tukey (p<0,05) showing there are significant differences between different treatments (p=0,003). The highest final hardness were in the groups: G1- F (281,36) and G4- F+L (242,87) (p<0,05) following G2- L (220,16) and G3- L+F (206,03) (p<0,05). In %SMHC was observed G3- L+F a significant increase in mineral contente (21,37%),
G4 (F+L) a small increase (0,96%), no G1 (F) a small decrease (6,59%) and G2 (L) a large reduction (25,63%) mineral concentration (p≤0,05). Based on the analyzes of hardness and% SMHC it could be observed that the treatment with F and F + L showed the highest values ​​of Knoop hardness final and a profile of stable mineral alteration, L + F group presented the lowest final hardness value and increased mineral content (21,37%).
Conclusions: It can be concluded that the surface treatment of enamel Fluoride associated with the Nd: YAG laser showed reduced progression of mineral loss against erosive challenge in vitro.