【摘要】 目的用三维有限元方法分析钛基台支持的不同■面厚度CAD/CAM全瓷单冠的应力情况,为种植冠部修复的临床设计提供理论参考。方法建立钛基台以及粘接固位的下颌第二前磨牙不同■面厚度全瓷单冠的三维有限元模型,在牙冠■面偏颊侧施加300 N的轴向静载荷,计算并分析全冠的应力情况。结果■面厚度分别为1.5、2.0和2.5 mm的玻璃陶瓷和氧化锆全冠,基台顶部中央处牙冠组织面的最大拉应力分别为21.0 MPa、15.5 MPa、15.2 MPa以及21.5 MPa、15.7 MPa、14.5 MPa。两种全瓷冠当牙冠■面厚度大于2 mm时,基台顶部中央处牙冠组织面的最大拉应力较小,应力的变化也较小;当牙冠■面厚度小于2 mm时,基台顶部中央处牙冠组织面的最大拉应力较大,应力的变化也较大。■面厚度相同的两种全瓷冠的应力场分布基本相同,应力值接近。结论在本实验的范围内,钛基台支持的玻璃陶瓷和氧化锆CAD/CAM全瓷单冠,当牙冠■面厚度小于2 mm时,■面是牙冠损坏的隐患部位,要谨慎调磨牙冠■面,其厚度的微小变化可能引起牙冠强度的明显下降。更多还原

【Abstract】 Objective To analyze the stress distribution on CAD/CAM all-ceramic crowns with different occlusal thickness supported with single-tooth implants. Methods Three-dimensional finite element models were constructed with cement-retained abutment to support mandibular second premolar crowns with different occlusal thickness. Axial loads of 300 N were applied at the occlusal buccal surface. Resulting principal stress was evaluated in relation to different occlusal thickness. Results On IPS e. max CAD and InCoris ZI CAD full crown, when the thickness of occlusal surface was 1.5 mm, 2.0 mm, and 2.5 mm respectively, the maximum tensile stress of the crown surface at the center of the abutment top was 21.0 MPa, 15.5 MPa, 15.2 MPa, and 21.5 MPa, 15.7 MPa, 14.5 MPa respectively. When the occlusal surface thickness of the two kinds of all-ceramic crowns was more than 2.0 mm, the maximum tensile stress of the crown surface at the center of the abutment top was smaller. When the occlusal surface thickness of the crown was less than 2.0 mm, the maximum tensile stress of the crown tissue surface at the center of the abutment top was larger. The stress field distribution of the two kinds of full crowns with the same occlusal thickness was basically the same, and the stress value was close to each other. Conclusion On IPS e. max CAD and InCoris ZI CAD full crowns supported with cement-retained titanium abutment, when the thickness of occlusal surface was less than 2.0 mm, the occlusal surface was the hidden dangerous part of crown. It should be carefully ground. A slight change in the occlusal thickness may cause a significant decrease in crowns strength.更多还原