Selective Infiltrated Etching to Surface Treat Zirconia Using a Modified Glass Agent

Purpose: The surface roughness of zirconia specimens and the bond strength of zirconia and resin cements were evaluated after selective infiltrated etching (SIE) surface treatment using a modified glass agent. Materials and Methods: One hundred twenty zirconia specimens were divided into four groups according to surface treatment method: untreated control (C), airborne particle abrasion (A), airborne particle abrasion followed by SIE treatment using a modified glass agent (A-SIE), and SIE treatment using a modified glass agent without airborne particle abrasion (SIE). The surface morphology and roughness of the specimens were examined before and after treatment using scanning electron and atomic force microscopy. The specimens were then cemented to resin blocks with a 4-META resin luting system (Superbond C&B). The shear bond strength of the zirconia/ resin interface was measured before and after thermocycling and fatigue testing. Results: The surface roughness and shear bond strength values of the SIE group were higher than those of the other three zirconia groups. The surface roughness (Ra) values were 8.10, 8.34, 9.42, and 12.42 μm for the C, A, A-SIE, and SIE groups, respectively, with significant differences between SIE and the C and A groups (p 0.05). The shear bond strength values before thermocycling and fatigue testing were 23.37, 23.38, 25.82, and 28.67 MPa for the C, A, A-SIE, and SIE groups, respectively. These values did not decrease after 10,000 cycles of thermocycling for the surface-treated groups, but did decrease for the untreated control group (C). Conclusion: SIE treatment using a modified glass agent can increase surface roughness and the bond strength between zirconia and resin cements. The shear bond strength did not decrease after thermocycling and fatigue testing. Keywords: zirconia, bond strength, selective infiltrated etching, surface modification, thermocycling test