Effect of nano-particle calcium hydroxide dressing on the push-out bond strenght of fiber post

Abstract

Introduction: Radicular posts are used for restoration and repair of endodontic teeth to achieve adequate retention of the final restoration. Fiber posts are aesthetic and they can form a single set with the root surroundings. Any change in dentin structure due to the use of washers, in-channel medications or sealers during root treatment can affect the bond strength of the dentin materials. So far, no study has been performed to demonstrate the effect of using nanoparticle calcium hydroxide on the post bond strength of post-cemented fiber to root dentin. Materials and Methods: 54 single root premolar teeth after CEJ excision and root implantation were randomly divided into two experimental groups and a control group (calcium hydroxide and nano calcium hydroxide) according to the type of dressing used inside the canal. Each group consisted of 18 teeth. After rinsing the drugs inside the roots, the specimens of all three groups were filled with gutta-percha and sealer. The post space was embedded to a depth of 9 mm. After inserting the resin cement into the root canal, the fibers were punctured in depth and the resin cement was polymerized by LED light cure. Transverse sections of all teeth were prepared as 1 mm thick discs for push out test. Data were analyzed using one-way ANOVA and Kruskal-Wallis tests in non-normal data using SPSS 17 software. The significance level of the study was P <0.05. Results: A significant difference was found between calcium hydroxide and control group (P = 0.02) no significant difference between nano-calcium hydroxide and control and calcium hydroxide groups. Also only the B level was significantly different among three groups. However, using calcium hydroxide had a significant difference in bond strength compared to the other groups (P = 0.008). In all three groups of nano-calcium hydroxide, calcium hydroxide and control, the push-out bond strength from coronal to apical was reduced. Conclusion: The use of calcium hydroxide significantly increased the fiber strength of push-out band while there was no significant difference between control and nano calcium hydroxide groups. Due to limitation of this study Nano calcium hydroxide can’t increase the Push-out bond strength of filer post.