Efeito de um primer cerâmico autocondicionante nas propriedades de superfície, mecânicas e adesivas de cerâmica à base de dissilicato de lítio cimentadas em diferentes substratos

Abstract

Introduction: Dental ceramics are widely used due to their esthetics, biocompatibility, and mechanical performance. The standard HF + silane protocol improves adhesion but has drawbacks like toxicity and technique sensitivity. Self-etching ceramic primers (SeCPs), such as Monobond Etch & Prime (MEP), offer a simplified alternative. However, their long-term effectiveness remains uncertain, especially on different substrates. Objective: This study evaluated the effect of the MEP, with or without aluminum oxide air abrasion, on the surface, mechanical, and adhesive properties of lithium disilicate-based ceramics (LD), luted to different substrates (dentin and composite resin), compared to conventional hydrofluoric acid and silane treatment (HF+S). Material and Methods: LD specimens were prepared in two formats: square-shaped (10×10×4 mm, N=134) for surface roughness (ΔSa), contact angle (CA), microtensile bond strength (μTBS), and scanning electron microscopy (SEM); and rectangular-shaped (15×2.5×1.5 mm, N=48) for three-point flexural strength (σf3P). Four groups were tested according to surface treatment: HF+S sandblasted, HF+S polished, MEP sandblasted, and MEP polished. After treatment, ΔSa, CA, and σf3P were measured. LD blocks were cemented to either composite resin or dentin to evaluate μTBS before and after thermocycling (TC, 10,000 cycles, 5 °C/55 °C, 30 s dwell time). ΔSa and CA were analyzed using one-way ANOVA/Tukey; σf3P, using twoway repeated-measures ANOVA/Tukey; and μTBS, using mixed ANOVA/Tukey. Results: Air abrasion significantly increased (p < 0.05) ΔSa (HF+S: 1.16 ± 0.12 μm; MEP: 0.85 ± 0.02 μm) compared to polished specimens (HF+S: 0.47 ± 0.04 μm; MEP: 0.38 ± 0.04 μm). The lowest CA was observed in the MEP sandblasted group (27.50 ± 4.09). Both MEPtreated groups showed σf3P values similar to the control (p > 0.05) and higher than HF (p < 0.05). Thermocycling reduced μTBS in all groups, but MEP-treated specimens showed greater bond strength stability (ΔμTBS ≤ 2.0 MPa). Sandblasted surfaces consistently exhibited higher μTBS than polished ones. HF+S and MEP performed similarly, except on composite resin before aging, where HF+S was superior. Conclusion: MEP with airborne-particle abrasion showed μTBS values similar to HF+S and greater adhesive stability after TC. Additionally, MEP improved wettability, preserved σf3P compared to HF, reduced ΔSa, and demonstrated consistent performance on dentin and composite resin.