| Porcelain-fused-to-medal restoration is the most prevalent technique in clinic recently for the fixed restoration of odonto-defect and dentition defect. The medal coping supplies enough strength, but it also reduces the translucency and stereoscopy,and makes the restoration's cervical margin have medal color, couldn't have a ideal effect. Further more, medal coping made by none-precious medal has bad anticorrosion, the medal ion from which can cause harms such as hypersensitivity and gingival stained . It has been an eager problem need to be solved with the development of focus on healthy safety and the requirement of esthetics. As a new restoration material, ceramic is being employed in the prosthodontics for its excellent biocompatibility, anticorrosion,especially its esthetics. However, almost all the ceramic materials used in clinic now are imported from foreign countries with high prices, which limits the development of all-ceramic restoration in clinic to some extent. Therefore, a good material with low price is needed. At the same time, a good combination between the base and the outer porcelain plays a key role in all-ceramic restoration. The alumina-glass and zirconia-glass composites used in this research are made by both the Forth Military Medical University and Qinghua university. In former study, all natural capacities were detected and they can meet the need of clinic. This research is to detect the shear bond strength between the base porcelain and outer porcelain: 1)Detect the bond strength between Vita In-ceram and Vita alpha opaque-dentine porcelain, and make this as control; 2) Detect the bond strength between the self-made alumina or zirconia glass-infiltrated ceramic composites and Vita alpha opaque-dentine porcelain, and compare with the control; 3)Detect the effect of different surface treatments such as sandblasting and etching of the composites on the bond strength..Result of experiment:1. The shear bond strength between Vita In-ceram alumina and Vitadur alpha opaque-dentine porcelain is 28.88MPa; sandblasting on the surfaces can increase the bonding strength to 35.95MPa (p<0.01); etching has no apparent effects on the bond strength of 26.77MPa (p>0.01).2. The shear bond strength between the self-made alumina-glass composites and Vitadur alpha opaque-dentine porcelain is 30.08MPa; Sandblasting and etching on the surfaces can increase the bonding strength manifestly to 41.07MPa and 41.94MPa respectively compared with the control(p<.001).3. The shear bond strength between the self-made zirconia-glass composites and Vitadur alpha opaque-dentine porcelain is 60.19MPa; sandblasting on the surfaces can increase the bonding strength manifestly to 63.59MPa(p<.001); Etching reduces the bonding strength to 35.48MPa(p<.001).4. Compared to Vita In-ceram alumina(28.88MPa), the bond strength between alumina-glass(35.89MPa),zirconia-glass (60.19MPa)composites and Vita alpha opaque-dentine porcelain are higher(p<0.01).Furthermore, the bond strength between zirconia-glass composites and outer porcelain is higher than it between alumina-glass composites and outer poecelain(p<0.01).The results above indicate:1. The bond strength between slef-made alumina-glass composites , zirconia-glass composites and outer surface can meet the need in clinic;Compare to slef-made alumina-glass composites,the bond strength between self-made zirconia-glass composites and outer surface is higher.2. Sandblasting can increase the bond strength between Vita In-ceram alumina , slef-made alumina-glass composites , zirconia-glass composites and outer surface.3.Etching can increase bond strength between slef-made alumina-glass composites and outer porcelain,while decrease it between self-made zirconia-glass composites and surface; to Vita In-ceram alumina, etching has no apparent effect.So, it needs further study to research the effect on the bond strength. |
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