Method: 180 polished (P600 grit) PEEK plates, PEEK-Optima® (Invibio®, Lancashire, United Kingdom) [Po]: n=140, BioHPPCam (Bredent medical, Senden, Germany) [Bc]: n=40 and BioHPP for2press (Bredent medical, Senden, Germany) [Bp]: n=40, were treated as follows (n=20/group): 1) sandblasting with RocatecTM Pre (110µ) and RocatecTM Soft (30µ) and silanisation with ESPE Sil (3M ESPE, St.Paul, USA) [Es], 2) sandblasting with Al2O3 (110µ) and application of Solobond Plus (Voco, Cuxhafen, Germany) [Sb] and 3) sandblasting with Al2O3 (110µ) and application of Visio.link (Bredent medical, Senden, Germany) [Vl]. Cylindical molds were fixed to the plates and filled with Sinfony TM plus opaquer (3M ESPE, St.Paul, USA) [So], Combo.lign (Bredent medical, Senden, Germany) [Cl] or Combo.lign plus opaquer [Co]. All specimens were divided into two subgroups [In, Tc: n=10] and stored in distilled water at 37°C for 72h. Bond strengths were tested in a universal testing machine immediately after water storage [In] and after additional thermal cycling [Tc] according to ISO 10477. Significance of the results was tested by multiple ANOVA and post-hoc-test by Duncan (p≤0.05).
Result: Initial bond strength ranged from 9.63 ± 1.76 MPa [PoSbClIn] to 25.46 ± 3.61 MPa [BpVlCoIn]. After thermal cycling bond strength ranged from 2.72 ± 2.16 MPa [PoSbClTc] to 23.40 ± 3.31 MPa [BpVlCoTc]. Statistically significant differences were detected according to type of PEEK, surface treatment, veneering composite and artificial aging.
Conclusion: Regarding ISO 10477 all tested groups were acceptable for clinical application, except PoSbClTc (2.72 ± 2.16 MPa). Bond strength values comparable to metal-composite bond (20 – 30 MPa as described in literature) were only achievable with surface treatment Vl.