Shear Bond Strength from Veneering Composite to Polyetheretherketone (PEEK) and Fiber-Reinforced Composite - Influence of Different Bonding Systems

Objectives: The purpose of this study was to determine the bond strength of direct composite to different high-performance polymers such as polyetheretherketon (PEEK) and indirect fiber-reinforced composite (FRC).
Methods: Ninety-six specimens made of PEEK and FRC were produced via Computer Aided Design/Computer Aided Manufacturing (CAD/CAM) and air-abraded with 50 μm aluminum-oxide particles. All specimens of each material were randomly allocated to four experimental groups according to the adhesive system used: Luxatemp Glaze&Bond, Scotchbond Universal, SR Nexco Connect and iBond Universal. Specimens were divided again into two subgroups (n=12) for short-term (14 days at 37°C, subsequently 5000 thermal cycles between 5 and 55°C) and long-term (200 days at 37°C, subsequently 37,500 thermal cycles) artificial aging. After artificial aging, shear bond strength (SBS) was evaluated. Failure modes were observed and classified as adhesive or partially cohesive, analyzed optically and by SEM analysis, and then analyzed by EDS analysis. SBS data were analyzed with the Kolmogorov-Smirnov test and the Mann-Whitney U test (p ≤ 0.05).
Results: After short-term artificial aging, SBS ranged from 3.78 to 13.85 MPa for PEEK and from 8.36 to 11.98 MPa for FRC. After long-term aging, SBS ranged from 0 to 8.75 MPa for PEEK and from 4.52 to 7.82 MPa for FRC. Failure mode analysis demonstrated that higher SBS values resulted in more partially cohesive failure.
Conclusions: Luxatemp Glaze & Bond and Scotchbond Universal can be recommended as promising bonding methods for PEEK after air-abrasion of the surfaces. Scotchbond Universal also showed promising SBS to FRC.