Fig. 4From: HF etching of CAD/CAM materials: influence of HF concentration and etching time on shear bond strengthSEM images of substrate surfaces feldspar ceramic (VM), polymer-infiltrated ceramic (VE), lithium disilicate (EC) and zirconia reinforced lithium silicate (VS) pre-treated with 5% hydrofluoric acid for the respective times 0 s, 5 s, 15 s, 30s and 60s. No differences were observed with SEM between HF5 and HF9. Magnification for VM and VE is 2′000x, for EC and VS 10′000xBack to article page