New Technologies to Prevent Root Caries Lesion

Objectives: This study evaluated the parameters of different lasers (Er:YAG, Nd:YAG and CO₂), associated or not to fluoride (F), on root dentin caries prevention.

Methods: 88 dentin samples obtained from 44 human molars were randomly divided in 7 experimental groups (n=11) and 1 group with standard samples (no treatment). A 9mm²-area (3mmX3mm) on dentin of each sample was irradiated (scanning mode) using the following parameters: G1- fluoride application without laser irradiation; G2- CO₂- 2W, no water; G3- similar to the G2, after fluoride application; G4- Nd:YAG- 0.5W/10Hz, no water; G5- similar to the G4, with F; G6- Er:YAG- 60mJ/2Hz; water flow (2.0mL/min); G7- similar to the G6, with F. Then, the samples were subjected to a 2-week cariogenic challenge (pH cycling), consisted of the daily immersion in de-remineralizing solutions for 6 and 18h, respectively. After that, samples were sectioned (150µm), polished and analyzed in light microscopy. The percentage of demineralization was measured and the groups were compared to standard samples. The obtained data were evaluated by ANOVA and Tukey tests (α=5%). 

Results: The G4, G5 and G6 showed lowest percentage of demineralization values and statistical different of the other groups in relation to the standard samples (p<0.05). 

Conclusions: The findings of the present study suggest that laser irradiation with Nd:YAG and Er:YAG can promote a caries preventive effect. Furthermore, there was no synergism of the prior application of fluoride. Financial Support: CNPq (grant # 141345/2009-8).