Papers by Author: Bing Deng

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.

Abstract: The aim of this study was to explored the effects of Fe2O3 and Bi2O3 on the color properties of a 3Y-TZP zirconia ceramics for dental application. Pigmented dental ZrO2 powders were prepared by mixing different concentration of Fe2O3 and Bi2O3, also in their combinations with 3Y-TZP powders. The mixture was compacted by isostastic pressure, then densely sintered. Color parameters were measured by Minolta CM2600d spectrophotometer. XRD was used to exam the structure of colored 3Y-TZP. Experimental results showed that the hue of the materials shift from yellow-green to yellow-red with the increasing concentration of the Fe2O3 and Bi2O3. Combined use of Fe2O3 and Bi2O3 could further decrease the L* value, which color scope was suitable for dental color matching. The XRD spectra showed only tetragonal phase was detected.