Surface Modification of CAD/CAM Fiber Post-and-Core to Enhance the Bonding Strength to Resin-Matrix Cements

Objectives: To evaluate the influence of different surface treatment methods of CAD/CAM fiber post-and-core on their bond strength to resin-matrix cements in endodontically treated teeth rehabiliation.
Methods: Thirty-six CAD/CAM fiber post-and-core blocks (10mm×10mm×8mm) were specifically manufactured for this study and randomly assigned into 6 groups considering surface treatment (Group 1, 3% hydrogen peroxide for 10min; Group 2, 30% hydrogen peroxide for 3min; Group 3, 30% hydrogen peroxide for 6min; Group 4, 30% hydrogen peroxide for 10min; Group 5, Air abrasion with aluminum oxide; Group 6, no treatment; n=6). A scanning electron microscope (T200 JEOL, Tokyo, Japan) was used to characterize the surface topography of the samples at magnifications of 500 x. The Single Bond Universal Adhesive (3M, USA) was applied on the surface of blocks. After that, a cylindrical templates (2mm high×2mm Ø) were fixed on each block, filled with composite resin and light-cured. Specimens were stored under 37°C for 24h and microshear tests were performed by Universal Mechanical Testing Machine.
Results: Different surface treatments led to different topographic alterations. The higher bond strength values were found in Group 4 and Group 5.
Conclusions: Air abrasion with aluminum oxide and Hydrogen peroxide are both effective surface treatments for increasing the bond strength of CAD/CAM fiber post-and-core. The application of Hydrogen peroxide is a convenient and effective clinical procedure for CAD/CAM fiber post-and-core surface treatment to enhance the bonding strength to resin-matrix cements.