Li Xiaoxuan, Shaw Leon L
Department of Metallurgy and Materials Engineering, Institute of Materials Science, University of Connecticut, 97 North Eagleville Road, U-136, Storrs, CT 06269-3136, USA.
Dent Mater. 2005 Apr;21(4):336-46. doi: 10.1016/j.dental.2004.05.006.
The goals of this study were to investigate the phase transformation and microstructure of dental porcelain bodies densified via a moving laser beam and to develop an understanding of how the microstructure of the dental porcelain varies with the laser processing condition and the position relative to the center of the laser beam.
A moving laser beam was used to scan and densify a commercial dental porcelain powder bed. The porcelain powder compact was also sintered using a furnace at different temperatures. The phase transformation and microstructure of these dental porcelain bodies were compared and investigated using a host of analytical instruments including scanning electron microscopy, X-ray diffraction, thermogravimetric analysis, and quantitative image analysis.
Based on the temperature dependence of the leucite content in the dental porcelain derived from the furnace-sintered samples, the temperature distribution in the dental porcelain body during laser densification was established. The microstructure of the laser-densified porcelain body was found to be dependent of the location relative to the center of the laser beam and the average laser densification temperature.
The understanding of how the microstructure of dental porcelain bodies varies with the laser processing condition and the location with respect to the center of the laser beam was developed. Based on this understanding, the laser processing condition has been optimized to achieve the desired microstructure and densification of dental porcelain bodies simultaneously.
本研究的目标是研究通过移动激光束致密化的牙科瓷体的相变和微观结构，并了解牙科瓷体的微观结构如何随激光加工条件以及相对于激光束中心的位置而变化。
使用移动激光束扫描并致密化商用牙科瓷粉床。还使用熔炉在不同温度下烧结瓷粉压块。使用包括扫描电子显微镜、X射线衍射、热重分析和定量图像分析在内的一系列分析仪器对这些牙科瓷体的相变和微观结构进行比较和研究。
基于从炉烧结样品获得的牙科瓷中白榴石含量的温度依赖性，确定了激光致密化过程中牙科瓷体内的温度分布。发现激光致密化瓷体的微观结构取决于相对于激光束中心的位置和平均激光致密化温度。
了解了牙科瓷体的微观结构如何随激光加工条件以及相对于激光束中心的位置而变化。基于这一认识，已优化激光加工条件，以同时实现所需的牙科瓷体微观结构和致密化。
