Surface Characteristics and Adhesion of Veneering Composite Resin to PAEK‐Based Substructure Restorative Materials

Abstract Purpose To evaluate and compare the shear bond strength (SBS) of composite veneering material to polyetherketoneketone (PEKK), polyetheretherketone (PEEK), zirconia (YZ), and nickel‐chromium alloy (NiCr) substructure restorative materials. Materials and methods Forty samples (12 × 2 mm) were prepared from four materials: PEKK, PEEK, zirconia, and NiCr alloy (n = 10). The Vickers hardness was evaluated before preparing the surface for bonding by shot‐blasting using 110 μm Al 2 O 3 particles. The surface roughness (Ra) of each sample was determined using a noncontact optical profilometer. The veneering resin was bonded onto each sample following primer application. The prepared samples were then subjected to an SBS test using a universal testing machine at 0.5 mm/min crosshead speed. Failure modes and surface topography following debonding were assessed. The data were statistically analyzed using ANOVA and Tukey's post‐hoc comparison test ( p < 0.05). Results The highest and lowest mean surface roughness was observed in PEEK (3.45 ±0.13 μm) and NiCr (1.87 ±0.07 μm) materials, respectively. A significant difference in roughness values was observed between the materials except for NiCr and YZ ( p = 0.547). Concerning SBS, PEEK and NiCr exhibited the highest (16.23 ±0.96 MPa) and lowest (10.1 ±0.63 MPa) values. The mean difference in SBS indicated a statistically significant difference between the material groups ( p < 0.01). Conclusions PEKK materials demonstrated significantly lower SBS than PEEK and significantly higher SBS values than conventional zirconia and alloy materials. A positive and significant correlation between mean roughness and SBS was observed, but the causality could be either intrinsic to the material or the roughness.