Effect of Er:YAG Laser on Bond Strength of Sealants

Objective: The purpose of this study was to evaluate the effect of Er:YAG laser enamel etching and/or phosphoric acid enamel etching on the shear bond strengths (SBS) of the fissure sealants. Methods: 42 extracted non-carious third molars, washed and cleaned with a fluoride–free pumice, were sectioned in the cement-enamel junction and the roots were discarded. Teeth were embedded in resin; labial surfaces of crowns were flattened for an enamel surface area of 3mm in diameter; the substrate surfaces were wet-ground with 600 grit SiC paper. The specimens were randomly assigned to six groups of 7 teeth each. Group 1: Enamel etching+ Clinpro Sealant(3M ESPE, USA), Group 2: Er:YAG laser etching(Fidelis Plus II,Fotona ) +Clinpro, Group 3: Laser+enamel etching+Clinpro, Group 4: Enamel etching+Fissurit F(Voco,). Group 5:Laser etching+Fissurit F, Group 6: laser+enamel etching+Fissurit F. Samples were etched with 37 % phosphoric acid gel for 20 sec. and/or Er:YAG laser (10 Hz, 120 mJ) Cylindrical molds (D:3mm,H:2mm) were placed on substrate surfaces; and sealants were applied according to manufacturers' instructions. The specimens were stored in DI water at 37ºC for 24 hours. Cylinders of fissure sealants were submitted to SBS test in an Instron machine at a crosshead speed of 1 mm/min. SBS data in MPa was statistically analyzed by Tukey Multiple Comparisons test using GraphPad Prism (V3.0) software. Results: Mean+SD values(MPa): Group1:14.52±2.33, Group2:5.43±2.02, Group3: 9.14±3,08, Group4: 9.39±2.94, Group5: 5.03±2.68, Group6: 8.31±2.41. Significant differences were determined between Gr 1-Gr 2 (p<0.001), Gr 1-Gr 3 (p<0.01), Gr 1-Gr 4 (p<0.01), Gr 1-Gr 5(p<0.001), Gr 1-Gr 6(p<0.01) and Gr 4-Gr 5(p<0.05). No significant differences were found between the other groups.Conclusions: Laser enamel etching, laser+ acid enamel etching have demonstrated lower SBS values for the fissure sealants tested than enamel acid etching.