Mechanical Properties of a new Dental all-ceramic Material-zirconia Toughened Nanometer-ceramic Composite

目的口腔全瓷修复体以其独特优越性受到医患青睐,但脆性问题一直限制其应用范围及使用可靠性.本研究旨在研制用于玻璃渗透全瓷修复的纳米氧化锆增韧陶瓷并全面检测评价其力学性能.方法采用化学共沉淀与球磨相结合的方法合成纳米氧化锆增韧陶瓷(α-Al2O3/nZrO2 ceramics powder ,W),扫描电镜评价陶瓷材料的粉体形态特征及粒度分布.预制氧化锆含量不同的陶瓷粉体(5wt%,10wt%,15wt% and 20wt%),采用粉浆涂塑技术将材料制成标准试件,并在不同温度下(1 200～1 600 ℃)烧结成型,用三点弯曲法及单边刀口梁法检测材料试件的抗弯强度和断裂韧性.结果1)α-Al2O3/nZrO2材料粉体粒度分布范围大致为0.02～3.0 μm,其中超细粉体(低于0.1 μm)占20%; 2)不同烧结温度组试件的力学强度有显著差异(P＜0.05),1 450 ℃和1 600 ℃组高于1 200 ℃组;3)相同烧结温度下不同氧化锆含量组材料强度有显著差异,一定范围内氧化锆含量增高有助于材料的增韧增强.结论本研究所研制的纳米氧化锆增韧陶瓷材料组分配比及微观特征能增韧增强材料,有望提高玻璃渗透后材料的综合力学性能.

Mechanical Properties of a new Dental all-ceramic Material-zirconia Toughened Nanometer-ceramic Composite

Objectives:All-ceramic dental restorations are attractive to the dental community because of their advantages.But they're also challenged by relatively low flexural strength and intrinsic poor resistance to fracture.This paper aims to investigate mechanical properties of a new dental all-ceramic material, i.e. zirconia toughened nanometer-ceramic composite (α-Al2O3/nZrO2).Methods:α-Al2O3/nZrO2 ceramics powder (W) was processed with combined methods of chemical co-precipitation method and ball milling. Scanning electron microscopy (SEM)was used to determine the particle size distribution and to characterize the particle morphology of the powders. Four kinds of powders with different ZrO2 content (5wt%, 10wt%, 15wt% and 20wt%) were prepared by using α-Al2O3 powder to dilute the higher ZrO2 content powder (W). The ceramic matrix compacts were made by slip-casting technique and sintering to 1 200～1 600 ℃. The flexural strength and the fracture toughness of the matrix materials were measured via three-point bending test and single-edge notch beam methods, respectively.Results:1) The particle distribution of the Al2O3/nZrO2 powder ranged from 0.02～3.0 μm, with the superfine particles almost accounting for 20%;2) There is a significant difference of flexural strength (P＜0.05) between the groups with 1 450 ℃ and 1 600 ℃ sintering temperature and 1 200 ℃;3) There is a significant difference of flexural strength (P＜0.05) between different zirconia volume fraction groups with the same sintering temperature, the ceramic matrix samples with higher nZrO2 (W) content had much better mechanical properties than those of pure α-Al2O3 ceramics.Conclusions:The studied nanometer α-Al2O3/nZrO2 powder was homogeously distributed within the matrix and had reasonable powder-size gradation to improve mechanical properties of ceramics.