Impact of air-abrasion pressure and adhesive systems on bonding parameters for polyetheretherketone dental restorations

Abstract Objectives To investigate the impact of polyetheretherketone (PEEK) surface modification on tensile bond strength (TBS), acidity parameters (D) and surface properties. Methods For TBS, 486 PEEK specimens were fabricated and air-particle abraded with 50 µm Al 2 O 3 according to varying pressure: 0.05, 0.2 or 0.4 MPa. Specimens were directly conditioned (n = 18/group): 1. Scotchbond Universal (SBU); 2. Clearfil Universal Bond (CUB); 3. Futurabond U (FBU), 4. Adhese Universal (AU), 5. G-Premio Bond (GPB), 6. Pekk Bond (PB), 7. visio.link (PCG/positive-control-group), 8. without conditioning (NCG/negative-control-group) and luted with Clearfil SA Cement. After thermal cycling (5,000x) TBS was measured. On air-particle abraded PEEK surfaces and different adhesive systems (n = 6/pretreatment) D was analysed by contact angle measurement, surface roughness tactile by profilometer and optical by SEM with 3D-images followed by surface topography, EDX- and XRD-analysis. Data was analysed using 2-/1-way ANOVA, Kruskal-Wallis H-, Mann-Whitney-U-, Kaplan-Meyer-, Chi²- and Spearman-Rho-test. Results PCG followed by SBU and AU showed the highest TBS and survival rates. PB air-particle abraded with 0.4 MPa presented comparable TBS with PCG. NCG and GPB showed lowest TBS. Specimens air-particle abraded with 0.05 MPa presented lower D-values than those with 0.2 or 0.4 MPa. PCG followed by PB showed higher D-values compared to SBU, CUB, FBU, AU and GPB. All air-particle abraded specimens showed embedded Al 2 O 3 -particles and for 0.2 and 0.4 MPa more roughened surface areas. Significance The pressure during air-particle abrasion of PEEK restorations must be matched to the adhesive system. A general recommendation is not possible. Universal adhesives might be an alternative conditioning for cementation of PEEK compared to PCG.