Laser Treatment and Shear Bond Strength of Resin

An in vitro study evaluated the effect of laser treatment on shear bond strength of a self-adhesive flowable resin composite to human dentin. The study involved 80 extracted sound human molar teeth. The teeth were sectioned mesiodistally and embedded in acrylic blocks. The dentin surfaces were ground wet with 600-grit silicon carbide (SiC) paper. They were randomly divided into 2 preparation groups: laser (Er:YAG laser, with 12 Hz, 350 mJ energy) and control (SiC). Each group was then divided into 2 subgroups according to the flowable resin composite type (n = 20). A self-adhesive flowable resin and a conventional flowable resin were used. Flowable resin composites were applied according to the manufacturer’s recommendations using the Ultradent Products shear bond Teflon mold system. The bonded specimens were stored in water at 37°C for 24 hours. Shear bond strength was tested at one mm/minute. The data were logarithmically transformed and analyzed using 2-way analysis of variance and Student-Newman-Keul’s test at a significance level of 0.05. The self-adhesive flowable resin showed significantly higher bond strength values to laser-prepared surfaces than to SiC-prepared surfaces (P < .001). The conventional flowable resin did not show such differences (P = .224). While there was a significant difference between the 2 flowable resin composites in SiC-prepared surfaces (P < .001), no significant difference was detected in laser-prepared surfaces (P  = .053). The study found that the bond strength of a self-adhesive flowable resin composite differs according to the type of dentin surface preparation. Laser treatment in­creased the dentin bonding values of the self-adhesive flowable resin.
(Source: Lasers in Medical Science, July 30, 2012)
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