添加相氧化铝对牙科纳米氧化锆陶瓷性能的影响

目的 通过测定不同Al2O3含量的牙科纳米氧化锫复合陶瓷材料的烧结密度、力学性能和可见光积分透射比,探讨Al2O3添加量对复合陶瓷力学性能及半透明性的影响.方法 分别测量Al2O3质量百分数分别为2.5%、5.0%、7.5%、10.0%的Al2O3组和对照组(不含Al2O3)氧化锆陶瓷试件的烧结密度、三点弯曲强度和断裂韧性,采用分光光度计测量可见光积分透射比,扫描电镜观察试件断面形貌.结果 对照组试件常压烧结下烧结密度为(6.04±0.03)g/cm3,接近理论密度,三点弯曲强度为(1100.27±54.82)MPa,断裂韧性为(4.96±0.35)MPa·m1/2,透射比高达17.03%;2.5%、5.0%、7.5%、10.0%Al2O3组随Al2O3含量的增加,试件的烧结密度和透射比下降,断裂韧性有所提高;Al2O3 4组间三点弯曲强度的差异无统计学意义(P>0.05);10.0%Al2O3组试件的断裂韧性为(6.13±0.44)MPa·m1/2,透射比明显降低至6.21%.Al2O3对四方氧化锆晶粒的大小和分布无明显影响.结论 添加Al2O3可影响氧化锆复合陶瓷的力学性能和半透明性,添加复合相需兼顾临床对陶瓷材料力学性能和透光性的要求.

Evaluation of alumina effects on the mechanical property and translucency of nano-zirconia all-ceramics

Objective To study the effects of alumina content on sintered density, mechanical property and translucency of zirconia nanocomposite all-ceramics. Methods Specimens of zirconia nanocomposite all-ceramics were divided into five groups based on their alumina content which are 0% (control group), 2. 5% , 5. 0% , 7. 5% and 10. 0% respectively. The sintered densities were measured using Archimedes' method. Specimens' bending strengths were measured with three-point bending test( ISO 6872). The visible light transmittances were measured with spectrophotometric arrangements and the fractured surfaces were observed using scanning electron microscope (SEM).Results The control group of pure zirconia could be sintered to the theoretical density under pressure-less sintering condition. The bending strength was (1100.27 ±54.82) MPa, the fracture toughness was (4.96 ±0.35) MPa·m1/2 and the transmittance could reach 17. 03%. The sintered density and transmittance decreased as alumina content increased from 2. 5% to 10%. However, the fracture toughness only increased slightly. In all four alumina groups, the additions of alumina had no significant effect on samples' bending strengths (P >0. 05). When the content of alumina was 10% , fracture toughness of specimens reached (6. 13 ±0.44) MPa·m1/2 while samples' transmittance declined to 6. 21 %. SEM results showed that alumina particles had no significant effect on the grain size and distribution of tetragonal zirconia polycrystals. Conclusions Additions of alumina to yttria-tetragonal zirconia polycrystals could influence its mechanical property and translucency. Additions of the other phase to zirconia ceramics should meet the clinical demands of strength and esthetics.