Effect of Argon Plasma and Sandblasting on Bond Strength of PEEK and PEKK to Resin Cement.

BACKGROUND This in vitro study evaluated the effect of different surface treatments on the bond strength of polyetheretherketone (PEEK) and polyether-ketone-ketone (PEKK) polymers to resin cement. MATERIAL AND METHODS CAD/CAM-fabricated PEEK and PEKK specimens (7×7×2 mm) were divided into 8 groups (n=10 per group; total n=80), with 4 groups per material: control, argon plasma, sandblasting with 125-µm Al₂O₃, and sandblasting followed by argon plasma. Surface characteristics were analyzed using scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and atomic force microscopy (AFM). All specimens were treated with a methyl methacrylate-based adhesive (Visio.link) and luted with resin cement (RelyX U200), then stored in air for 1 h. Shear bond strength was measured using a universal testing machine. Data were analyzed using Kolmogorov-Smirnov, Levene, one-way ANOVA, Bonferroni, and independent t tests (alpha=0.05).   RESULTS Surface treatment significantly affected bond strength (P<0.05). The highest bond strengths for both polymers were achieved with sandblasting followed by argon plasma treatment. Although PEKK showed slightly higher bond strengths than PEEK, the difference was not statistically significant (P>0.05). The lowest bond strengths were observed in the control groups (PEEK: 7.1±0.6 MPa; PEKK: 7.6±1.2 MPa), while the highest values were recorded after combined sandblasting and argon plasma treatment (PEEK: 12.2±2.4 MPa; PEKK: 12.6±2.4 MPa).   CONCLUSIONS Surface treatment significantly influences the bond strength of PEEK and PEKK to resin cement. Argon plasma application after sandblasting markedly enhanced shear bond strength for both materials.