Effect of an MMA-Containing Adhesive Primer on the Surface Characteristics of Sandblasted PEEK and Its Bond Strength to Dental Resin Cements

This study evaluated the effects of the methyl methacrylate (MMA)-containing adhesive primer Visio.link on the surface characteristics of sandblasted poly(ether ether ketone) (PEEK) and its bond strength to four dental resin cements: the MMA-based resin cement Super-Bond EX (SB) and the composite-based resin cements RelyX Universal Resin Cement (RX), G-CEM LinkForce (GC), and Panavia V5 (PA). Sandblasted PEEK specimens were tested with or without primer application. Surface morphology, surface roughness, and surface free energy were evaluated, and shear bond strength (SBS) was measured after 1 day of water storage and after 20,000 thermal cycles. Primer application smoothed the sandblasted surface, reduced surface roughness, increased the polar component, and decreased the dispersive component and total surface free energy. Primer application significantly increased the initial SBS of RX, GC, and PA; however, thermal aging reduced bonding durability and caused pretest debonding in several groups. For SB, primer application did not significantly affect the initial SBS, whereas the sandblasted group showed significantly higher SBS than the primer-treated group after aging. The effect of the MMA-containing primer therefore depended on resin cement type and aging condition. These findings suggest that primer application should be considered according to the composition and bonding mechanism of the resin cement rather than routinely incorporated into PEEK bonding procedures.