首页> 外文期刊>Journal of the mechanical behavior of biomedical materials >Viscoelastic finite element analysis of residual stresses in porcelain-veneered zirconia dental crowns
【24h】

Viscoelastic finite element analysis of residual stresses in porcelain-veneered zirconia dental crowns

机译:瓷胶合氧化锆牙冠残留应力的粘弹性有限元分析

获取原文
获取原文并翻译 | 示例
           

摘要

The main problem of porcelain-veneered zirconia (PVZ) dental restorations is chipping and delamination of veneering porcelain owing to the development of deleterious residual stresses during the cooling phase of veneer firing. The aim of this study is to elucidate the effects of cooling rate, thermal contraction coefficient and elastic modulus on residual stresses developed in PVZ dental crowns using viscoelastic finite element methods (VFEM). A three-dimensional VFEM model has been developed to predict residual stresses in PVZ structures using ABAQUS finite element software and user subroutines. First, the newly established model was validated with experimentally measured residual stress profiles using Vickers indentation on flat PVZ specimens. An excellent agreement between the model prediction and experimental data was found. Then, the model was used to predict residual stresses in more complex anatomically-correct crown systems. Two PVZ crown systems with different thermal contraction coefficients and porcelain moduli were studied: VM9/Y-TZP and LAVA/Y-TZP. A sequential dual-step finite element analysis was performed: heat transfer analysis and viscoelastic stress analysis. Controlled and bench convection cooling rates were simulated by applying different convective heat transfer coefficients 1.7E-5 W/mm(2) degrees C (controlled cooling) and 0.6E-4 W/mm(2) degrees C (bench cooling) on the crown surfaces exposed to the air. Rigorous viscoelastic finite element analysis revealed that controlled cooling results in lower maximum stresses in both veneer and core layers for the two PVZ systems relative to bench cooling. Better compatibility of thermal contraction coefficients between porcelain and zirconia and a lower porcelain modulus reduce residual stresses in both layers.
机译:瓷胶合氧化锆(PVZ)牙科修复物的主要问题是由于在胶凝式燃烧过程中的冷却阶段开发有害残余应力而导致塑料瓷器的切片和分层。本研究的目的是阐明冷却速率,热收缩系数和弹性模量的影响,使用粘弹性有限元方法(VFEM)在PVZ牙科冠中产生的残余应力。已经开发了一种三维VFEM模型来预测使用ABAQUS有限元软件和用户子程序来预测PVZ结构中的残余应力。首先,使用Vickers压痕在平PVZ标本上验证新建立的模型。找到了模型预测和实验数据之间的良好协议。然后,该模型用于预测更复杂的解剖学 - 矫正冠系统中的残余应力。研究了具有不同热收缩系数和瓷质模量的两个PVZ冠系统:VM9 / Y-TZP和LAVA / Y-TZP。进行了顺序双步有限元分析:传热分析和粘弹性应力分析。通过施加不同的对流传热系数1.7e-5w / mm(2)°C(控制的冷却)和0.6e-4w / mm(2)°C(板凳冷却)来模拟控制和台对流冷却速率。暴露于空气的冠状表面。严格的粘弹性有限元分析显示,控制冷却导致两个PVZ系统的胶合和芯层中的最大应力较低,相对于台式冷却。瓷器和氧化锆之间的热收缩系数的更好兼容性和较低瓷模量减少了两层中的残余应力。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱:kefu@zhangqiaokeyan.com

京公网安备:11010802029741号 ICP备案号:京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有
  • 客服微信

  • 服务号