The Preparation And Study Of Dental Glass-infiltrated Zirconia Composite

Glass-infiltrated Zirconia composite is a kind of dental material, which plays an important role in Prosthodontics practices. Properties of ZrO2 blank uninfiltrated would have great effect on that of the composite. In this study, effects of powder-milling techniques and the ratio of Al2O3/ZrO2 in the ZrO2 blank on properties of the glass-infiltrated composite were investigated, and formation of residual pores was observed and analyzed as well by the means of scanning electron microscopy (SEM) and X-ray diffraction (XRD). Several key techniques were established, such as preparation of zirconia blanks and specific glass used for infiltration, glass-infiltration process, and the optimum ratio of Al2O3/ZrO2, etc. In order to ensure that the material can be safely used in clinical practices, partial results of biocompatibility experiments for the material were provided as reference. The results are as follows:1. The microstructure of the blanks made from nano-size zirconia powderand micron-size alumina powder, along with that of corresponding glass-infiltrated composite, demonstrate that nano-size zirconia powder has a bad dispersion during molding process, which would lead to formation of plentiful residual pores after infiltration. The optimum sintering temperature was considered as 1300C and the soaking time is 2 hours.2. During preparation of glass-infiltrated zirconia composite, powder milling with agate milling media would mingle agate granules with alumina powder and form lacunas in the composite subsequently. Otherwise, by applying alumina milling media to the powder-milling process, the amount of lacunas can be reduced dramatically.3. The glass-infiltrated composite adding with 40wt%3Y-ZrO2 has the optimum mechanical properties. Its flexural strength, fracture toughness, elasticity modulus and hardness were 440+62Mpa, 6.12+0.37 Mpa-m1/2,215+12Gpa and 7.65+0.17Gpa, respectively.4. The results of biocompatibility experiments indicate that the as-got glass-infiltrated zirconia composite has a reliable biocompatibility, which can measure up to ISO-7406 criterion.