Durable polyetheretherketone-resin bonding enabled by sulfonation, polyhedral oligomeric silsesquioxane grafting, and acetone pretreatment.

OBJECTIVES: This study aimed to evaluate the effects of sulfuric-acid sulfonation, ultraviolet (UV)-initiated grafting of methacrylate-functionalized polyhedral oligomeric silsesquioxane (MA-POSS), and acetone pretreatment on the durability and interfacial properties of polyetheretherketone (PEEK)-resin bonds, without compromising the mechanical performance and in-vitro cytocompatibility of PEEK.

METHODS: Polished PEEK specimens were randomly assigned to five groups: (A) untreated; (B) 60 s sulfonation; (C) UV-initiated MA-POSS grafting; (D) combined sulfonation and grafting; (E) acetone-pretreated SP-PEEK before bonding. Resin-composite cylinders were bonded with a universal adhesive; shear bond strength was measured immediately and after 10,000 thermocycles (5-55 °C; n = 10 per group). Surface and interfacial morphology were examined by SEM; surface chemistry and wettability were assessed by XPS, FTIR, and contact angle measurements; and surface roughness was determined by AFM. Flexural properties were assessed by three-point bending, and cytocompatibility with primary human gingival fibroblasts by Live/Dead staining and CCK-8.

RESULTS: Sulfonation produced a porous layer; MA-POSS grafting introduced methacrylate groups; acetone pretreatment increased adhesive penetration by 46.8% (P < 0.05) and reduced voids. The combined treatment yielded 23.74 ± 1.33 MPa SBS, higher than untreated PEEK (P < 0.05), with 10.45% loss after 10,000 thermocycles; flexural properties and cytocompatibility were unchanged.

SIGNIFICANCE: Integrating micromechanical retention and covalent coupling, aided by acetone-enhanced wetting, improves the PEEK-resin interface without compromising the substrate properties or cytocompatibility. This effective strategy warrants further clinical evaluation.