Effect of Laser Treatment, Self-Adhesive Resin Cement Brand and Thermocycling on Push out Bond Strength of Fiber Reinforced Post

Abstract

The interface between the adhesive resin and fiber posts has an important role in their performance. However, It was found that the most frequent cause of their failure is debonding at the adhesive resin-dentin interface. The aim of the present study was to evaluate the effect of laser treatment: Erbium, Diode or no treatment; and two brands of self-adhesive resin cement: hydrophobic (Smartcem2) and conventional (Breeze); in addition to the effect of thermocycling on push out bond strength of Glassix fiber-reinforced composite post. A total of ninety-six freshly extracted natural human teeth were equally divided into three main groups after root canal treatment, decoronatin and post space preparation. Teeth of group 1 were treated with Er,Cr:YSGG laser, group 2 were treated with Diode laser, while the teeth of group 3 [control] received no laser treatment. Posts in half of the speciemens of the three groups were cemented with hydrophobic resin cement (Smartcem2) and the rest were cemented with conventional resin cement (Breeze). Samples of each group were further subdivided into two subgroups according to whether they were thermocycled or not. Three slices of 3mm-thickness: cervical, middle and apical were prepared from each root. Then a push-out test was performed using universal testing machine at a strain rate of 0.5 mm/min. Data were analyzed using Unpaired t test. One-way analysis of variance (ANOVA) test was used to study the effect of different variables' interactions. This was followed by Tukey's post hoc test when a significant difference was detected. The significance level was set at p ≤ 0.05. The results revealed that the Er,Cr:YSGG -2790 nm laser afforded greater bond strength than the diode laser. The hydrophobic self-adhesive resin cement demonstrated higher bond strength than the other brand. In addition, thermal stresses induced by thermocycling reduced the bond strength of Glassix fiber post.