Analysis Of Reinforce Dental Feldspathic Porcelain By Different Sintering Methods

The potassic feldspathic porcelain has been successfully used as the dental repairing material for about two hundred years because of its mechanical properties and esthetics. However, the application is limited by its low strength. Even though Porcelain-fused-to Metal could improve the strength enough, it has the disadvantage of potential metal erosion and the color of metal may shine through the slight edge at the cervical. Thus, it's important to study new materials with both esthetics and high strength.The material properties are mainly induced by micro-structure. In this paper, different sintering methods were used to reinforce ceramic. XRD, TEM, DSC et.al were used to analyse its micro-structure and the difficulty which micro-hardness has in measuring the feldspathic porcelain mechanical properties. A new technique that nano-indentation was adopted to analyse the influence to the feldspathic porcelain mechanical properties in different sintering methods. The results show that the normal pressure sintering temperature is 1250℃by ordinary moulding and holding time is 60min. After high pressure moulding, the normal pressure sintering temperature is 1200℃and holding time is 60min.The high pressure rapid sintering temperature is 1100℃and holding time is 5min. The spark plasma sintering (SPS) temperature is 1120℃and holding time is 10min. With analysis of X-ray, the feldspathic porcelain is composed of feldspathic and glass. With the analysis of metallography and AFM, it proved that both the ordinary moulding and high pressure moulding have pores and grain growth in normal pressure sintering. After high pressure rapid sintering and spark plasma sintering, the ceramics are very compact and the grain refined. With the analysis of TEM to the SPS sample there are crystal nucleus in the glass phase. With the Nano-Indentation measuring ,we analyse the effect of different micro-structures on the whole ceramics hardness. The result show that the hardness of SPS samples glass phase is obvious higher than theothers. Based on the results, the spark plasma sintering is the optimum sintering method to obtain the high reinforced dental feldspathic porcelain.