Effect of a self-etching ceramic primer on the surface, mechanical, and adhesive properties of lithium disilicate-based glass-ceramics bonded to different substrates

Abstract

This laboratory study evaluated the effect of a self-etching ceramic primer (Monobond Etch & Prime – MEP), with or without grit blasting, on the surface, mechanical, and adhesive properties of lithium disilicate (LD) ceramics, compared to hydrofluoric acid and silane (HF + S). LD specimens were prepared in two geometries: square-shaped (10 mm × 10 mm × 4 mm) for surface roughness (ΔS_a, μm), contact angle (CA), microtensile bond strength (μTBS), and scanning electron microscopy (SEM); and rectangular-shaped (15 mm × 2.5 mm × 1.5 mm) for three-point flexural strength (σf3P). Four groups were tested: HF + S grit-blasted (HF + S[g]), HF + S polished (HF + S[p]), MEP[g], and MEP[p]. After treatment, ΔS_a, CA, and σf3P were measured. LD blocks were cemented to composite or dentin to evaluate μTBS before and after thermocycling (TC, 10,000 cycles, 5 °C/55 °C, 30 s dwell time). Grit blasting significantly increased ΔS_a (HF + S[g]: 1.16 ± 0.12; MEP[g]: 0.85 ± 0.02) compared to polished specimens (HF + S[p]: 0.47 ± 0.04; MEP[p]: 0.38 ± 0.04), with the lowest CA observed in MEP[g] (27.50 ± 4.09°). HF + S-treated groups showed the lowest σf3P. TC reduced μTBS in all groups, but MEP-treated specimens exhibited greater adhesive stability (ΔμTBS ≤2.0 MPa). Grit-blasted surfaces showed higher μTBS than polished ones. HF + S and MEP performed similarly, except on composite before TC, where HF + S was superior. In conclusion, MEP[g] demonstrated μTBS comparable to HF + S, provided greater adhesive stability after TC, enhanced wettability, better preserved σf3P, reduced ΔS_a, and showed consistent μTBS to resin cement on both dentin and composite substrates, supporting its effectiveness as a reliable surface treatment for LD ceramics.