摘要
目的应用三维有限元法分析动态加载下种植体植入位置和直径对悬臂梁种植固定义齿应力的影响。方法建立左下颌第二前磨牙、第一磨牙、第二磨牙缺失种植固定义齿的三维有限元模型,远中种植体的位置和直径保持不变;近中种植体依次向远中移动形成中轴与第一前磨牙远中面距离D分别为5.5、8.0、10.5、13.0 mm的悬臂梁种植固定义齿,分别采用4.1和4.8 mm两种直径的种植体;以250 N力模拟咀嚼周期0.875 s的动态载荷加载于颊尖和舌尖上,应用有限元分析软件MSC.Marc和Partran分析种植体—骨组织界面的Von Mises应力情况。结果随着近中种植体逐渐向远中移动,近远中种植体Von Mises应力均有不同程度增高,近中种植体中轴与第一前磨牙远中面距离D≤8.0 mm范围内种植体最大Von Mises应力增幅缓和,D>8.0 mm时应力急剧加大;近中种植体直径增大,则近远中种植体的应力减小;各加载阶段最大Von Mises应力均处于近远中种植体颈部与皮质骨交界处;斜向加载种植体应力显著大于垂直加载。结论种植体植入位置是影响悬臂梁种植固定义齿应力的重要因素,悬臂梁长度不超过前磨牙宽度时行种植固定义齿设计是可行的,直径的选择要考虑骨量和悬臂梁长度双重因素。
Objective To examine the effect of the location and diameter of implants on stress distribution in three-unit implant-supported posterior cantilever fixed partial dentures （FPD） in the mandible. Methods A three-dimensional finite element model was developed to represent a rigid implant-supported posterior FPD that restores the second left premolar, first molar, and second molar. The location of the distal implant with a diameter of 4.8 mm remained the same, whereas the mesial implants with diameters of 4.1 and 4.8 mm were successively moved toward the posterior area with distances of 5.5, 8.0, 10.5, and 13.0 mm from the long axis of the mesial implants to the first premolar to form the cantilever FPD. Dynamic loads of 250 N were applied from different directions on the buccal and lingual cusps of the FPD to simulate the masticatory cycle for 0.875 s. The maximum Von Mises stresses were calculated using the finite element analysis software MSC. Marc and Partran. Results The maximum Von Mises stresses of the mesial and distal implants increased to some extent as the me- sial implants moved toward the posterior area. Significant increases in the maximum Von Mises stresses were obtained when the mesial implants were located more than 8.0 mm posterior to the first premolar, and moderate increases in the stresses were observed when the mesial implants were located less than 8.0 mm posterior to the first premolar. The use of a broader implant reduced the stress on the interface between the bone and the implants. The maximum Von Mises stresses were found in the cervical region of the mesial or the distal implants cortical bone adjacent to the during stages II to IV of the masticatory cycle. Off-axial loading induced more stresses compared with vertical loading. Conclusion The location of implants in three-unit implant-supported posterior cantilever FPD is a significant factor that influences the stress generated in the interface between the bone and the implants. An implant- supported cantilever FPD is a feasible option for restoring missing teeth when the length of the cantilever is not greater than the width of a premolar. Two important factors should be considered before choosing the implant diameter, namely, bone volume and cantilever length.
出处
《华西口腔医学杂志》
CAS
CSCD
北大核心
2013年第6期552-556,共5页
West China Journal of Stomatology
关键词
种植固定义齿
悬臂梁
动态载荷
有限元分析
implant-supported fixed partial denture
cantilever
dynamic loads
finite element analysis
