Abstract:

Objective:This investigationwas to analyze the mechanism of formation of porous structure by studying some characteristics of the alumina powder used forGI-ⅡInfiltrate Ceramic.Methods:The alumina powder crystal type was analyzed with X-diffractome- ter, and its size distributionwas obtained by powder size analysis device, and fracture surface of alumina adobe was observed under scanning electronic microscope.Results:Alumina crystalswere purelyAtype, with firmest structure and best stability. Fine pow- derwhose size was smaller than 015Lm occupied 9 wt% (mass) and, coarse powder with sizes between 1 to 315Lm occupied 75wt% (mass). The SEM graphs of adobe showed that fine powders were attached to the surface of coarse powders, dispersed evenly, and alumina powders contacted each other firmly.Conclusion:The crystal type, size distribution and even dispersion of the studied alumina powder contributed to the formation of porous structure of alumina sintered body (preform), whichwas the ma- terial prerequisite in forming porous preform and one of the key factors to the rise of strength of GI-ⅡInfiltrated Ceramic.

Key words: dentalmaterial, infiltratedceramic, alumina, porousstructure