Plastic damage induced fracture behaviors of dental ceramic layer structures subjected to monotonic load.
Plastic damage induced fracture behaviors of dental ceramic layer structures subjected to monotonic load.
复制标题
DOI：
10.1111/jopr.12035
复制
发表时间：
2013-08
期刊：
影响因子：
--
通讯作者：
Raorao Wang;Chenglin Lu;D. Arola;Dongsheng Zhang
中科院分区：
文献类型：
--
作者：
Raorao Wang;Chenglin Lu;D. Arola;Dongsheng Zhang
目的采用实验和数值计算相结合的方法，对陶瓷结构的失效模式和断裂强度进行比较。材料与方法从两种陶瓷系统(IPS e.max Ceram/e.max PRESS-CP和Vita VM9/Lava Zirconia-VZ)制备12个具有扁平层结构的试件，并在单调载荷下用碳化钨球断裂。采用数字图像相关(DIC)和断口分析技术对试件的断裂行为进行了分析。用数值模拟的方法对两种牙科陶瓷的应力分布进行了分析。结果所有病例的烤瓷压痕下均有类塑性破坏。总体上，VZ试件的断裂强度大于CP试件。VZ和CP的起裂载荷分别为958±50N和724±36N。从试件表面的DIC观察，裂纹是由塑性损伤引起的，随后在弹塑性边界处被拉应力驱动，并向下延伸到单板/芯材界面。在VZ试件中，裂纹沿瓷质/氧化锆核界面偏转扩展，但未穿透氧化锆核。VZ和CP陶瓷的断裂载荷分别为1150±170N和857±66N。结论准塑性变形(损伤)是两种冠瓷体内裂纹形成的主要原因。由于其固有的力学性能，这两种陶瓷的断裂行为是不同的。高强度、高弹性模数的氧化锆芯比E.max芯具有更好的抗折性能。
PURPOSE The aim of this study was to compare failure modes and fracture strength of ceramic structures using a combination of experimental and numerical methods. MATERIALS AND METHODS Twelve specimens with flat layer structures were fabricated from two types of ceramic systems (IPS e.max ceram/e.max press-CP and Vita VM9/Lava zirconia-VZ) and subjected to monotonic load to fracture with a tungsten carbide sphere. Digital image correlation (DIC) and fractography technology were used to analyze fracture behaviors of specimens. Numerical simulation was also applied to analyze the stress distribution in these two types of dental ceramics. RESULTS Quasi-plastic damage occurred beneath the indenter in porcelain in all cases. In general, the fracture strength of VZ specimens was greater than that of CP specimens. The crack initiation loads of VZ and CP were determined as 958 ± 50 N and 724 ± 36 N, respectively. Cracks were induced by plastic damage and were subsequently driven by tensile stress at the elastic/plastic boundary and extended downward toward to the veneer/core interface from the observation of DIC at the specimen surface. Cracks penetrated into e.max press core, which led to a serious bulk fracture in CP crowns, while in VZ specimens, cracks were deflected and extended along the porcelain/zirconia core interface without penetration into the zirconia core. The rupture loads for VZ and CP ceramics were determined as 1150 ± 170 N and 857 ± 66 N, respectively. CONCLUSIONS Quasi-plastic deformation (damage) is responsible for crack initiation within porcelain in both types of crowns. Due to the intrinsic mechanical properties, the fracture behaviors of these two types of ceramics are different. The zirconia core with high strength and high elastic modulus has better resistance to fracture than the e.max core.