摘要
目的分析钛基台支持的CAD/CAM全瓷单冠在载荷位置不同时全冠的应力情况,为种植上部结构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牙冠的三维有限元模型,在基台上方偏颊侧(a)、基台正上方(b)、基台上方偏舌侧(c)的牙冠■面3个不同部位分别施加300N的轴向静载荷,计算分析全冠的应力情况。结果对于玻璃陶瓷全冠,当载荷作用于位置a时,最大拉应力在舌侧颈缘处,约为13MPa;最大压应力位于颊侧颈缘处,约为-45MPa。载荷作用于位置b时,最大拉应力在与基台顶部中心区域接触处的牙冠组织面,约为20MPa。载荷作用于位置c时,最大拉应力在牙冠颊侧颈缘处约为15MPa;舌侧颈缘处最大压应力值为-40MPa。氧化锆全冠在三种载荷类型时的应力场分布与玻璃陶瓷全冠类似,应力值大小不同。结论钛基台支持的CAD/CAM全瓷单冠,当载荷作用于位置a时,牙冠颊侧颈缘应增加强度以防止折裂,牙冠舌侧颈缘处应防止脱粘接;载荷作用于位置b时,基台上方牙冠■面需要增加强度;载荷作用于位置c时,牙冠颊侧颈缘处易发生脱粘接,舌侧颈缘处容易折裂。
Objective To evaluate the stress distribution of CAD/CAM all-ceramic crowns supported by single-tooth implants when loading on different occlusal locations. Methods A three-dimensional finite element model was constructed with cement-retained abutment to support mandibular second premolar crown. Axial load of 300 N was applied at the following locations, respectively: occlusal buccal surface(a), center of occlusal surface above the abutment (b), and occlusal lingual surface (c). Resulting principal stress was evaluated in relation to different load sites. Results On IPS e.max CAD full crown, when loading at the site (a), the highest tensile stress (13 MPa) and compressive stress (-45 MPa) were observed at the lingual and buccal cervical margin of the crown, respectively. When loading at the site (b), the highest tensile stress (20 MPa) was observed at the center contact area of crown and the top of abutment. When loading at the site (c), the highest tensile stress (15 MPa) and compressive stress (-40 MPa) were observed respectively at the buccal and lingual cervical margin of the crown. InCoris ZI CAD full crown in three types of load had the similar stress field distribution and different stress value compared with that of IPS e.max CAD full crown. Conclusion On CAD/CAM all-ceramic crowns supported with cement-retained titanium abutment, when the load was applied at the occlusal buccal surface, the buccal coronal margin of crown could be strengthened to prevent fracture, and the lingual coronal margin of crown was prone to debonding. When the load was applied at the center of occlusal surface, the thickness of crown occlusal surface was enough. When the load was applied at the occlusal lingual surface, the buccal cervical margin of the crown was liable to be debonded and the lingual cervical margin is liable to be fractured.
作者
王淑英
江青松
蒋向华
聂云清
WANG Shu-ying;JIANG Qing-song;JIANG Xiang-hua;NIE Yun-qing(Department of Prosthondontics, Capital Medical University School of Stomatology, Beijing 100050, China)
出处
《北京口腔医学》
CAS
2019年第2期72-75,共4页
Beijing Journal of Stomatology
作者简介
通讯作者:江青松, E-mail:13621163187@126.com,电话:010-57099210.
