Preparation And Properties Of The New Glass Infiltrated 3Y-TZP All Ceramic Dental Materials

The all-ceramic dental materials have been the research hotspots of dental restoration materials because they have good bio-compatibility, anti-abrasive and esthetics. However, both the intrinsic brittleness of ceramic and its difficult machining limit the application of all-ceramic restoration for dental use. With the appearance of glass-infiltration technology, all-ceramic dental materials have got a further development. The mechanical properties of alumina-glass composites and spinell-glass composites based on glass-infiltration technology are hard to get further substantial enhancement. While zirconia-based ceramic composites have a great improvement potential because of their superior mechanical properties. The remarkable mechanical properties of zirconia are mainly due to the phase transformation toughening.The raw material of ceramic matrix is 3 mol% yttria stabilized tetragonal zirconia (3Y-TZP) powder in this paper, which have a multi-modal particle size distribution. The porous 3Y-TZP matrix with a porosity ranged 9.8% to 40.8% was prepared. The influence of pre-sintering temperature and molding pressure on 3Y-TZP ceramic matrix were researched. The ceramic matrix with good mechanical properties and appropriate porosity was obtained in the paper, and the porous 3Y-TZP matrix have excellent machining performance.Different components of phosphate glass, La2O3-Al2O3-SiO2 glass and MgO-Al2O3-SiO2 glass were prepared. The melting temperature range and mechanical properties of the different glass were measured, and the components of the glass which could be used as infiltration glass were decided by melting temperature and mechanical property of the glass. The glass were infiltrated into porous 3Y-TZP matrix at a certain condition, and the influence of molding pressure and infiltration time on composites was studied. Therefore, the best molding pressure of matrix and the full infiltration time were detected.It was found that the addition of appropriate amount ZrO2 and Y2O3 in phosphate glass was beneficial to enhance chemically compatible of phosphate glass with 3Y-TZP matrix. The phosphate glass was infiltrated into 3Y-TZP matrix at 1100℃for 3 h, the porosity of the composites was almost zero. The shrinkage of the phosphate glass/3 Y-TZP composites was as low as 0.1% because of the low infiltration temperature, which could attain the near net-shape fabrication purpose. The mechanical property of the composites had a noticeable improvement, yet it couldn't be satisfied to clinical use.In order to get higher mechanical properties of glass/ceramic composites, the La2O3-Al2O3-SiO2 glass with good mechanical property and permeability was infiltrated into 3Y-TZP matrix at 1200℃for 4 h, the pores of the matrix had been almost filled by the glass. The flexural strength and the fracture toughness of the composites were 710 MPa and 6.5 MPa·m1/2, respectively, and the shrinkage of the composites was as low as 0.3%. The various properties of composites have reached the clinical use standard.The MgO-Al2O2-SiO2 glass having outstanding mechanical property was infiltrated into 3Y-TZP matrix at 1200℃for 6 h, the pores of the matrix had been almost filled by the glass. The flexural strength and the fracture toughness of the composites were 441 MPa and 5.9 MPa·m12, respectively, and the shrinkage of the composites was as low as of 0.6%.