Influence of different luting cements on the shear bond strength of pretreated lithium disilicate materials

Aims: The aim of the study was to examine the shear bond strength of different luting cements bonding to pre-treated lithium disilicate materials. Materials and methods: Sixty A2 shade lithium disilicate discs were subjected to either micro-etch with aluminum trioxide and etching by 10% hydrofluoric acid (micro-etch group; n = 30); or etching with 10% hydrofluoric acid (acid-etch group; n = 30) before cementation. Three dual-cure Variolink Esthetic (VDC), RelyX Ultimate (RUT), and RelyX Unicem (RUC) and three light-cure Variolink Veneer (VV), Variolink Esthetic (VLE), RelyX Veneer (RV) resin cements were used for cementation. The specimens from each group were tested for shear bond strength (SBS). The data were analyzed using two-way ANOVA; p < 0.05 is considered statistically significant. Results: For all resin cements tested with different surface treatments, there was a statistically significant difference within resin cements per surface treatment (p < 0.05). The SBS in the micro-etch group was significantly higher across all the cements tested when compared to the acid-etch group (p < 0.05), thus suggesting that surface treatment affects the SBS largely irrespective of the resin cement. Their interaction between cement and the surface treatment was significantly different across groups (p < 0.001). Conclusion: Under the limitations of the present study, it can be concluded that surface treatment influences the bond strength irrespective of the resin cement (light/dual-cure) used for indirect restorations' cementation. The shear bond strength in the sand blast/acid etch group was significantly higher across all the cements tested when compared to the acid-etch alone. Clinical significance: The surface treatment of porcelain veneer hugely influence the SBS, which will directly affect the veneer clinical success rate. The micro-etching recorded a higher shear bond strength when compared to those with acid-etch only.