Adhesive performance of simplified protocols for adhesion to lithium disilicate ceramics.

Abstract

Background: Durable adhesion to glass-ceramic materials such as Lithium disilicate (LD) relies on effective surface conditioning strategies involving etching, salinization, and adhesive application. While conventional multi-step protocols have demonstrated reliable bonding performance, simplified systems have been introduced to reduce clinical complexity. However, their impact on long-term adhesive interface stability and resistance to degradation remains a subject of investigation. Objective: This study aimed to evaluate the immediate and long-term shear bond strength (SBS) and interfacial durability of resin cement bonded to LD using different conventional and simplified surface treatment protocols. Methods: Forty LD cylinders (IPS e.max Press, Ivoclar Vivadent, Schaan, Liechtenstein) were randomly assigned to four groups (n = 10): HSil (9.5% hydrofluoric acid etching + separate silane application (Bisco, Schaumburg, IL, USA)), HSBU (hydrofluoric acid + Single Bond Universal adhesive (3M ESPE, St. Paul, USA)), HCFU (hydrofluoric acid + Clearfil Universal Bond adhesive (Kuraray, Tokyo, Japan)), and MBEP (self-etching primer Monobond Etch & Prime (Ivoclar-Vivadent, Schaan, Liechtenstein)). Resin cement (Choice 2, Bisco, Illinois, USA) was applied following surface treatment. Half of the specimens were tested after 24 h of water storage, and the remaining half after 6 months. SBS was measured using a universal testing machine, and failure modes were analyzed. Statistical analysis was performed using two-way analysis of variance (α = 0.05). Results: After 24 h, the HSil group exhibited the highest mean SBS (29.29 ± 4.40 MPa), whereas the MBEP group showed the lowest values (21.39 ± 5.54 MPa). After 6 months, the HSBU group demonstrated the highest SBS (22.87 ± 10.38 MPa), while the HCFU group presented the lowest values (15.89 ± 7.15 MPa). No statistically significant differences were observed among groups at either time point (p ≥ 0.159), and no significant reduction in bond strength was detected after aging (p ≥ 0.079). Failure mode analysis revealed a predominance of adhesive failures across all groups. Conclusions: This study found that simplified surface treatment protocols, including self-etching primers, provide LD bonding performance comparable to conventional methods over 6 months. While conventional approaches initially demonstrated higher bond strength, all techniques exhibited comparable stability after artificial aging, supporting the use of simplified approaches to reduce marginal degradation and improve hygiene-related outcomes.