Vanadium-functionalized methyl methacrylate-based primer enhances self-curing and bonding of resin cement to polyetheretherketone restorations

Background/purpose: Polyetheretherketone (PEEK) has gained considerable attention as a prosthetic material due to its favorable mechanical properties and biocompatibility. Although methyl methacrylate (MMA)-based primers are commonly used for PEEK surface pretreatment in clinical practice, a reliable method for achieving consistent bonding performance has yet to be established. This study aimed to evaluate the effects of incorporating functional components, such as 10-methacryloyloxydecyl dihydrogen phosphate (MDP), 3-(trimethoxysilyl) propyl methacrylate (TPM), and vanadium, into an MMA-based primer on the bond strength, polymerization, and mechanical properties of dual-cure resin cements bonded to PEEK. Materials and methods: PEEK specimens were sandblasted with alumina and pretreated with MMA-based primers containing various concentrations of MDP, TPM, or vanadium. Three types of dual-cure resin cements (G-CEM ONE [GO], RelyX Unicem 2 [RU], and BeautiLink SA [BS]) were used. The shear bond strength, degree of conversion (DC), and Vickers hardness were measured. Results: PEEK showed no detectable light transmittance, resulting in a significantly lower DC of the underlying resin cement. Application of the MMA-based primer improved the shear bond strength to PEEK; however, incorporation of MDP or TPM did not enhance bonding. In contrast, vanadium incorporation significantly increased the shear bond strength, DC, and Vickers hardness of all the resin cements tested. Conclusion: The incorporation of vanadium into MMA-based primers enhances both the adhesion and polymerization of dual-cure resin cements to PEEK, supporting its potential as a broadly applicable strategy for reliable bonding, particularly in clinical situations where light access is limited.