烧结次数对金瓷冠微观结构的影响

Effects of the number of firing on microstructure of metal-ceramic crown

目的 研究烧结次数对金瓷冠瓷表面及断面结构的影响。方法 利用扫描电镜 ,观察不同烧结次数金瓷冠试件的表面结构 ;观察Instron万能材料测试机对试件牙合面垂直加载 30 0N后 ,表面结构的变化 ;观察破坏实验后瓷断面的结构。结果 ①随烧结次数增加 ,金瓷冠表面裂纹增多 ,由窄到宽 ,由浅到深 ;气孔增多、变大 ;晶体由均匀一致变为大小不一。②加载后金瓷冠表面均出现表浅裂纹密集等变化 ,尤其多次烧结组变化更明显。③随烧结次数增加 ,瓷断面裂纹增多 ,气孔增多变大 ,玻璃样结构也由平坦均质变为高低不平的片块状结构。结论 烧结次数对金瓷冠瓷结构有影响。随烧结次数增加 ,瓷结构中裂纹增多 ,气孔增多变大 ,晶体也由均匀一致变为大小不一。

Objective To study the effects of the number of firing on the surface structure of metal-ceramic crowns and its porcelain's fracture sections.Methods The surface structure of metal-ceramic crowns with different number of firing were observed by scanning electron microscope (SEM); its changes were observed after vertical loading 300N on occlusal surface with Instron testing machine;the fracture ceramic sections structure was observed after destruction test.Results ①On metal-ceramic crowns' surface,with the number of firing increased,the cracks increased from narrow to wide,from shallow to deep.The pores on the surface increased and became bigger,the uniform crystals changed to different size crystals.②After loading,the surface of metal-ceramic crowns displayed many shallow cracks,especially obvious after repeated firing crowns.③ With the number of firing increased,at the fractured ceramic sections,the cracks increased and the pores became bigger.The glassy structure changed from uniform shape to segmental pieces.Conclusion The number of firing had effects on the structure of metal-ceramic crowns.With the number of firing increased,the structure of metal-ceramic crowns displayed many cracks and bigger pores,the crystals changed from uniform size to different size.