Effects of Surface Treatment on the Microstructural and Crystallographic Changes of Dental 3Y-TZP Ceramic

Abstract

Objective: To investigate the effects of different surface treatments on the microstructural and crystallographic changes of dental 3Y-TZP ceramics. Methods: 21 pieces of zirconia specimens (15 ´ 15 ´ 1.5 mm) were prepared and divided into 7 groups: control group; grinding group; polishing group; sandblasting group; sandblasting + veneer porcelain sintering group; sandblasting + veneer porcelain sintering twice group and sandblasting + annealing group. The crystal structure of specimen was monitored by X-ray diffraction (XRD) before morphological observation with scanning electron microscope. Results: monoclinic phase increased after grinding while decreased little after polishing, bigger phase change presented after sandblasting compared with decreased phase change induced by veneer porcelain sintering; annealing eradicated the surface m phase. Grinding produced coarse scratches on the surface of samples with removal of surface particles; after grinding and polishing to 7 um level, the surface particles were removed massively, and the surface became smooth with remaining scare scratches and substantial micro cracks. Sandblasting removed scratches near completely producing coarse and irregular surface of samples. Conclusions: Grinding, sandblasting and polishing could produce the transition of Zirconia Ceramic surface from t to m phase. It is better to use heat treatment after mechanical treatment to reverse the changed surface phase.