ABSTRACT
Because of the dental profession's increased utilization of light-cured restorative materials, there has been a corresponding increase in research into the light sources used to initiate polymerization. The argon laser is one promising sources, as the wavelength of light emitted by the laser is optimal for the initiation of polymerization of composite resins. The use of argon laser [488 nm] has been suggested as a new alternative for polymerization of restorative materials. The aim of this study was to compare the shear bond strength values of one composite resin polymerized with two cuing methods: Conventional visible light curing unit [for 20 and 40 seconds] and argon-laser 488 nm [or 10 and 15 seconds curing times]. Sixty freshly extracted human molars were prepared to receive composite resin samples in four groups [15 samples each]. The teeth were centrally horizontally mounted in plastic molds with cold cure epoxy resin. Flat occlusal surfaces were prepared and smoothed. One-step self-etching dental adhesive [Xenol 11, one- step self - Etching Dental Adhesive, Dent-sply Detrey Gmbh, 78467 Kanstang, Germany] was applied to the dentine surface and cured. Composite resin [Spectrum universal composite, series 007782, Shade A2, Dentsply Detrey, Germany] was inserted into standardized Perspex mold and polymerized with a visible light curing unit and an argon laser. Samples were stored in deionized water at 37°C for 48 hours. The bonds were stressed using shear forces at a crosshead speed of 0.5 mm/min using Lloyd testing machine. The shear bond strength was calculated to the four groups and statistical analysis performed [One-way ANOVA and LSD test]
Results: there was significantly higher shear bond strength of composite cured with argon laser compared with the conventional curing method. There was no statistical significant difference between curing times of the same light source