지르코니아 표면에칭처리와 저온열화현상이 지르코니아와 전장도재의 결합강도에 미치는 영향

Abstract

The purpose of this study was to investigate the influence of etching surface treatment and aging treatment of zirconia on the shear bond strengthbetween zirconia core and veneered ceramic. Four groups of zirconia-ceramic specimens were prepared; 1) NEZ group (no etching zirconia), 2)EZ group (etching zirconia), 3) ANEZ group (aging and no etching zirconia), 4) AEZ group (aging and etching zirconia). The shear bond strengthbetween zirconia and porcelain was measured using Instron Universal Testing Machine. Surface texture with crystalline structure of zirconia surfacewas examined by the field emission scanning electron microscopy (FE-SEM) with ingredient analysis. The fractured surfaces of specimens wereexamined to determine the failure pattern by a digital microscope. The mean±standard deviation of shear bond strengths were 23.47±3.47 Mpain NEZ, 28.30±4.34 Mpa in EZ, 21.85±4.65 Mpa in ANEZ, 24.65±3.65 Mpa in AEZ group, respectively, and were significantly different (p＜0.05). The average shear bond strength was largest in EZ group, followed by AEZ, NEZ, and ANEZ groups. Most specimens in NEZ group showedadhesive failure and most specimens in EZ, AEZ, and ANEZ group showed mixed failure. Surface of etching treatment group (EZ and AEZ) showedcomplex micro-structure and irregular surface texture which may facilitate mechanical interlocking, while untreated zirconia surface presentedsimpler micro-structure. In conclusion, an etching treatment improved bonding strength between zirconia and porcelain by forming mechanical interlocking.