Evaluation of Bond Strength of Two types of Resins with Different Viscositiest to Lithium Disilicate Glass Ceramic after Two Types of Surface Treatments. (In vitro study)

Purpose: To evaluate microtensile bond strength (TBS) of two types of resin with different viscosities: High viscosity resin (Flowable composite) and Low viscosity resin (Light cured resin cement) With lithium disilicate discs after two types of surface treatment: Laser etching ( Er,Cr:YSGG pulsed laser), hydrofluoric acid etching Materials and Methods: Ceramic slices (n=28) were prepared from IPS Emax CAD/CAM blocks, two surface treatments were applied followed by silane primer: Er,Cr:YSGG laser (group A) and hydrofluoric acid (group B). Two self-adhesive resin cements were injected to the emax specimens using ethelyne tube: flowable composite Z350 (High viscosity resin) sub group (I), mojo veneers resin cement (low viscosity resin) (subgroup II). Thermo-cycling using THE-1100 SD Mechatronics thermocycler was done to simulate the oral cavity media,each bonded micro-cylinder assembly resin was subjected to microtensile bond strength. Data was tabulated and statistically analyzed. Results: HF acid etching & silanation as Surface treatment had a significantly higher (meanSD) value than Laser surface etching followed by silanation with both high and low viscosities resin. High viscosity resin (flowable composite) should higher bond strength than low viscosity resin (light cure resin cement) but it was statistically insignificant. Conclusions: Acid etching followed by silanation had a significantly higher value than laser etching followed by silanation for both resin viscocities. Resin with high viscosity had a higher value of micro-shear bond strength than resin with low viscosity yet the difference was not significant.