In vitro evaluation of enamel demineralization around the brackets after Er-YAG laser irradiation and flouride application

Objective: The aim of this in vitro study was to investigate the effects of a fluoridated agent and Er:YAG irradiation with different doses, alone or in combination, on enamel resistance to demineralization. Materials and Methods: This study consisted of 80 premolars divided into eight groups: G1, untreated (control); G2, Acidic Phosphate Fluoride (APF) for 4 min; G3, 0.50 W Er:YAG laser; G4, 0.50 W Er:YAG laser + APF; G5, 0.75 W Er:YAG laser; G6, 0.75 W Er:YAG laser + APF; G7, 1 W Er:YAG laser; G8, 1 W Er:YAG laser + APF. Brackets were bonded to the buccal surfaces of premolars, and demineralization values were measured before and after treatment from the gingival aspects of the brackets, with DIAGNOdent. In last timepoint surface roughness was detected with Atomic Force Microscopy (AFM). All groups were subjected to 5 and 9 days of pH-cycling to produce artificial carious lesions. Data were tested using the Kruskal-Wallis, Friedman and Duncan tests (p<0.05). Results: G1 and G7 demonstrated significant demineralization when compared to the initial measurements to 5th day measurement (p<0.05). The other groups did not reveal significant changes in the demineralization values (p>0.05). The best surface was observed in the AFM records of group 4. Conclusion: Optimum Er:YAG laser irradiation with settings has a positive effect on the decrease in demineralization