Influence of Surface Modification Protocol and Type of Luting Cement on Bonding of Monolithic Zirconia to Dentin Substrate

AIM AND OBJECTIVE To assess microtensile bond strength (μTBS) of two types of luting cement to monolithic zirconia and dentin following various surface modifications and aging. MATERIALS AND METHODS Monolithic zirconia blocks were divided into four main groups. Group N: no surface modification; Group SB: sandblasted using 50 μm Al2O3 particles. Group GH: glazed with a thin film of low-fusing porcelain glaze and etched with 10% hydrofluoric acid for 60 seconds. Group CJ: sandblasted with CoJet sand. Surface-treated ceramic blocks were bonded to dentin using either self-adhesive cement or resin-modified glass ionomer cement and submitted to 3 or 150 days of water storage protocol with aging. The specimens were subjected to tensile force until de-bonding. Surface roughness (Ra, μm) was assessed after surface treatment. Analysis of variance (ANOVA) tests followed by Tukey's tests were used to analyze the data (α = 0.05). RESULTS Surface modification using selective infiltration etching (SIE) showed significantly higher μTBS (p < 0.05) compared to tribochemical silica coating, sandblasting, and no treatment groups. The surface roughness of the SB and CJ groups were statistically higher compared to GH and N groups. CONCLUSION Selective glass infiltration etching was an effective method in altering the surface properties, creating a strong and durable bond to monolithic zirconia. CLINICAL SIGNIFICANCE Surface treatment procedures using SIE techniques combined with the use of universal 10-Methacryloyloxydecyl dihydrogen phosphate (MDP)-containing adhesives could establish a long-lasting and strong bonding to monolithic zirconia restorations. Resin-modified glass-ionomer cement (RMGIC) is an alternative luting cement for monolithic zirconia based on the assessment of its bond strength and bond durability.