Selective effect of atmospheric non-thermal plasma on resin cement shear bond strength to glass ceramics

The effectiveness of non-thermal plasma (NTP) in improving the bond strength of different resin cements to different glass ceramics under various surface treatment protocols remains unclear. Moreover, the influence of specific plasma devices and the material-dependent response of ceramic–resin cement systems to NTP have not been sufficiently investigated. The purpose of this in vitro study was to evaluate the effect of NTP on the shear bond strength of different resin cements to different glass ceramics by comparatively assessing multiple surface treatment protocols. A total of 240 specimens of each glass ceramic group (IPS e.max CAD (E), Vitamark II (V)) were divided into 24 groups according to the combination of 6 surface treatments ((control), hydrofluoric acid (HF)+ceramic primer (Pr), Pr, HF+plasma (Pl) + Pr, Pl + Pr, and Pl) and two different resin cements (Single Bond+RelyX Ultimate (R) and ZenitCem (Z)). NTP was applied with an AC microsecond pulse power supply (5 kHz, 20 kV, 90 s). Specimens were cemented to composite cylinders. After storage in an oven, SBS was measured. The results were analyzed using three-way ANOVA, post-hoc tests, and targeted pairwise comparisons, with the significance level set at α = 0.05. The effectiveness of NTP is material- and cement-dependent and should be considered as a selective surface modification strategy rather than a universal alternative to conventional surface treatments. The V-Pl-Z group showed significantly higher SBS values than the V-Z group, and these values were within the clinically acceptable range ( p < 0.05). In the V groups treated with HF + Pr and HF + Pl+Pr, R demonstrated higher bond strength values than Z. HF surface treatment increased the SBS values for all groups ( p < 0.05). The effectiveness of NTP is material- and cement-dependent and should be considered as a selective surface modification strategy rather than a universal alternative to conventional surface treatments This study demonstrates that atmospheric non-thermal plasma does not universally enhance ceramic–resin cement bonding. Its effectiveness depends on the ceramic substrate, resin cement type, and surface treatment protocol. Clinicians should therefore apply plasma selectively.