Micro-shear bond strength of 3D printed hybrid ceramic with non-thermal plasma surface treatment: in-vitro study

​ The optimal surface treatment for developing a durable bond of dual-cure self-adhesive resin cement and 3D printed hybrid ceramic has not yet been established. To evaluate the effect of Non-Thermal Atmospheric Plasma (NTAP), sandblasting (SB), and a combination of both techniques on Micro-Shear Bond Strength (µSBS) of dual-cure self-adhesive resin cement bonded to 3D printed hybrid ceramic after thermocycling, and assess the failure mode using SEM. A total of 75 resin tags of dual-cure self-adhesive resin cement (TheraCem) were cemented to fifteen discs of 3D Printed Hybrid Ceramic (Saremc- Print Crowntec) (five resin tags/ disc). Specimens were allocated into five groups according to discs’ surface treatment (n = 15); PL group: specimens were treated with NTAP, S50 group: specimens were treated with 50 μm AL2O3 SB, S110 group: treated with 110 μm AL2O3 SB, SP50 group: treated with 50 μm AL2O3 SB followed by NTAP, and SP110 group: treated with 110 μm AL2O3 SB followed by NTAP. Resin cylinders, 0.8 mm in diameter and 1 mm height, were cemented to discs. The µSBS test was performed using a universal testing machine after thermocycling. SEM was used to analyze the failure mode. Data were analyzed using Welch one-way ANOVA followed by the Games-Howell post hc test. A significant difference between groups (P = 0.026). The highest value was measured in SP50 (2.70 ± 0.49) (MPa), followed by SP110 (2.37±0.38) (MPa), then PL (2.35 ± 0.57) (MPa), and S110 (2.18 ± 0.31) (MPa), while the lowest value was found in S50 (2.12 ± 0.75) (MPa). Post hoc pairwise comparisons showed SP50 to have significantly higher values than S110 and S50 (P < 0.05). NTAP, particularly when combined with 50 μm sandblasting, improved µSBS to 3D-printed hybrid ceramics under the conditions of this in-vitro study. Clinical validation is recommended.