A comparative evaluation of shear bond strength of the porcelian laminates using different surface treatments: an in-vitro study

Background: Porcelain laminate veneers rely on the synergistic bonding achieved between the porcelain and resin cement in order to survive the rigours of the oral environment. The enhancement of bonding through modification of the internal porcelain surface is advocated in order to increase the intimacy of the bond and may be achieved by exposing the porcelain surface to various treatments. Objectives: To compare and evaluate the effect of different ceramic surface pre-treatments on the shear bond strength of porcelain laminates with resin cements to human teeth. Methods: Forty samples of porcelain laminates (IPS Empress 2) were fabricated and randomly assigned into three different surface pre treatment conditions: (i) Group A: etched with 1.23% of APF gel for 10 minutes, (ii) Group B: sandblasted with 50 μm Aluminium oxide, (iii) Group C: etched with 5% hydrofluoric acid for 20 seconds, (iv) Group D: with no surface treatment.All samples were silanated before cementation with Variolink N resin cement. The shear bond strength was measured in a universal testing machine with cross-head speed of 1.0 mm/min. Data was compared by one-way ANOVA at 5% significance level. Results: Surface pre treatment with 5% HF exhibited the highest mean shear bond strength (22.451 ± 2.710 MPa) followed by sandblasting (15.659 ± 3.569), APF gel (13.025 ± 1.618) and control (10.60 ± 1.384) group. There was a significant difference between 5% HF (p<0.001) and other groups. Conclusion: Within the limitations of this study, it may be concluded that etching with 5 % HF produced favorable micromechanical retention.