To evaluate the effect of six universal adhesives and sandblasting on the bond strength and durability between polyetheretherketone (PEEK) and composite resin under different storage conditions.

A PEEK disk was cut into twelve cube specimens with the side length of 2 cm. Six specimens were sandblasted with alumina. The six universal adhesives are: Tetric N-Bond Universal (TNU) , Single Bond Universal (SBU) , DX.BOND UNI (DXB) , Selective Etch Bond (SEB) , Gluma Bond Universal (GBU) and Prime & Bond Universal (PBU) . The experiment was divided into seven groups with four sandblasted surfaces and four unsandblasted surfaces in each group. Seven surface treatments were: no adhesive applied (control group) and six brands of universal adhesive (experimental groups: TNU group, SBU group, DXB group, SEB group, GBU group and PBU group) . After surface preparation, the flowable composite resin F00 was injected into a transparent mold on the specimen surface without pressure for light-curing. The shear bond strength (SBS) test was carried out after water storage (37 ℃, 24 h) and thermocycling (3000 times) . The photograph and fracture mode analysis were performed using Tele-macro mode of Shofu EyeSpecial C-Ⅳ dental camera. The data from SBS were analyzed by using Three-Way ANOVA (thermocycling, adhesive and sandblasting) , and Turkey (α = 0.05) .

After water storage, the highest bond strength was achieved by the TNU in the non-blasting group (9.92 ± 1.19) MPa and the sandblasting group (9.97 ± 1.03) MPa, respectively; After 3000 times thermocycling, the best bonding performance was achieved by PBU in the non-blasting group (6.75 ± 0.99) MPa and the sandblasting group (7.22 ± 1.30) MPa, respectively. The Three-Way ANOVA analysis indicated that the SBS was significantly affected by thermocycling (F = 3 045.429, P<0.001) , adhesive (F = 361.165, P<0.001) and sandblasting (F = 80.050, P<0.001) ; There was significant interaction between the three factors: thermocycling and adhesive (F = 155.724, P<0.001) , adhesive and sand blasting (F = 3.535, P = 0.002) , as well as thermocycling and sandblasting (F = 9.184, P = 0.003) . The interaction among thermocycling, adhesive and sand blasting was significantly different (F = 12.392, P<0.001) .

(1) The bond strength of the universal adhesive between composite resin and PEEK was significantly improved by sandblasting after 37 ℃ water storage for 24 h; (2) The bond strength between composite resins and PEEK significantly decreased after thermocycling for 3000 times; (3) The bonding durability of PBU was superior to other universal adhesives in the present study.