Effect of Corona Discharge Treatment on the Adhesion of Polyetheretherketone Using Resin Cement

Background/Objectives: Although polyetheretherketone (PEEK) has been widely used for its excellent properties, its chemical inertness remains an ongoing challenge. This study aims to evaluate the effects of corona discharge (CD) treatment on the adhesion of dental PEEK to resin cement. Methods: Mirror-polished (MP) or sandblasted (SB) PEEK specimens were divided into CD-treated [CD(+)] and -untreated [CD(−)] groups. Following primer application, the specimens were bonded with resin cement and subjected to either 0 (TC0) or 5000 (TC5000) thermal cycles. The tensile bond strength (TBS) was measured and statistically analyzed using one-way ANOVA and t-tests (α = 0.05). Failure modes were analyzed and classified as adhesive, mixed, or cohesive. The surface roughness and contact angle were also evaluated. Results: CD treatment increased the surface roughness of the MP specimens while slightly decreasing that of the SB specimens. The wettability of both surfaces was significantly improved after CD treatment. However, no significant differences in TBS between the CD(−) and CD(+) groups were observed for either the MP or SB specimens. No significant differences in TBS were observed under different TC durations, regardless of CD treatment. Conclusions: Although CD treatment significantly improved the surface roughness and wettability of dental PEEK, it did not enhance the TBS of either the MP or SB surfaces.