Evaluation of bond strength of resin nano-ceramic as post material

Introduction
Different usage areas of newly developed restorative materials have increased.. Objectives: The purpose of this study was to investigate usability of a newly produced resin nano-ceramic (RNC) as a post material, and how to increase bond strength of different post systems to root canal dentin.

Material and methods
Crowns of eighty extracted maxillary central incisors were separated transversally at cementoenamel junction. The specimens were then endodontically prepared. Post spaces were opened at a diameter of 1.8 mm with a length of 10 mm on the root, maintaining 4 mm of filling material in apical third. 40 RNC post and 40 fiber post samples were divided into 4 sub-groups (n = 10), and different surface treatments were divided into control (Cnt), tribochemical coating (Tbc), and laser-irradiated (Lsr 1 and Lsr 2) groups. After adhesive cementation of posts to root canal dentin, the specimens were cut with 1 mm thicknesses. Push-out bond strength (PBS) tests were performed using a universal testing machine, and the results were analyzed using two-way analysis of variance and Tukey tests.

Results
The highest PBS value for fiber post groups was observed in the Tbc group (6.51 MPa). The highest PBS values were observed in the Tbc group (6.22 MPa), particularly in the RNC post group, and this value was statistically different from the other groups (p < 0.05).

Conclusions
Tbc treatment of posts may be a suitable way for increasing the bond strength. The experimentally produced RNC posts showed PBS values close to the prefabricated fiber posts. Therefore, they could be an alternative restorative material for repairing endodontically treated teeth.