Effect of Tribochemical Surface Treatment Technique on the Push-Out Bond Strength of Novel CAD/CAM Post Restorations

Abstract

Objectives: The purpose of this study was to investigate the effect of tribochemical surface treatment (TBC) on the push-out bond strength (PBS) of novel CAD/CAM post materials to root canal dentin.Materials and Methods: Fifty-two freshly extracted human maxillary central incisors were selected and endodontically treated. The teeth were randomly divided into 7 groups according to the post material used: fiber-reinforced composite post as control (FRC), zirconia (ZR), lithium disilicate (LDS), zirconia-reinforced lithium silicate (ZLS), nano-ceramic (RMC_CE), nanoparticle-filled (RMC_LU), and polymer-infiltrated-ceramic (RMC_EN).Then the posts, except FRC, were randomly assigned into two sub-groups according to the surface treatment technique used: Control (no treatment), TBC (CoJet). Following post space preparation, posts were cemented with dual-cure self-adhesive resin cement. A total of 156 sections were obtained (n=12), 3 sections on each root of the tooth. The PBS test was performed for each slice and the results were analyzed by using two-way ANOVA and Tukey HSD tests (α=0.05). The fracture modes were examined. Results: The lowest PBS values were obtained for ZR post groups that untreated (17.24±1.33 MPa) and tribochemical coated (23.09±2.16 MPa) (p<0.05). The highest PBS values were obtained for untreated RMC_CE (42.45±2.42 MPa) and RMC_LU (45.22±2.32 MPa) groups (p=0.215) and, tribochemical coated RMC_CE (43.55±2.63 MPa) and RMC_LU (45.38±2.59 MPa) groups (p=0.821). Significant differences were observed between the remaining post groups (p<0.05). Tbc has been significantly increased the PBS values of LDS, ZLS, and ZR post groups (p<0.05). Adhesive failure was the most common failure mode. (n=78). Conclusion:The results of this study proved that the PBS values of the CAD/CAM RMC post groups were higher than the FRC, ZR, LDS, and ZLS post groups, and TBC increased the PBS values of all CAD/CAM post groups.