Major in Mechanical Systems Engineering, Graduate School of Science and Engineering, Ibaraki University, Nakanarusawa, Hitachi, Ibaraki, Japan.
Biomed Mater Eng. 2020;31(1):19-33. doi: 10.3233/BME-201077.
In some treatments using multiple dental implants, the implants are inserted in the bone with splinted or non-splinted implant prostheses. There are some reports about the influence of the splinted and non-splinted implants on stress distribution in the bone using the finite element method (FEM), and there is a controversy in the literature regarding whether the splinted or non-splinted implants prostheses reduce the stress generated on the implant-surrounding bone more efficiently. Additionally, the simple shape of the jaw bones with limited bone area was used for FEM analysis in many studies at the expense of accurate analysis.
The aim of this study was to evaluate the difference in stress distribution in the bone between the splinted and non-splinted implants, and between completely and partially edentulous mandibles.
The implants were inserted in the first premolar, second premolar, and first molar regions of the partial and complete mandibles, and the splinted and non-splinted crowns were attached to the implants. Vertical load (100 N) or oblique load (70 N, 30° from its long axis towards the lingual) was applied on the first premolar.
When vertical load was applied to the partially edentulous mandible model, the stress was concentrated intensively on the cortical bone around the first premolar regardless of whether splinted or non-splinted implants were used. On the other hand, the vertical load applied to the completely edentulous mandible model caused the stress to be concentrated intensively on the cortical bone around the first premolar with non-splinted implants. With respect to the oblique load, the stress was concentrated intensively on the cortical bone around the first premolar only with the non-splinted implants, in both the partial and complete mandibles.
This study shows the different stress distributions of the cortical bone around the implants between the partial and complete mandible. This indicates that the complete mandible should be used for the analysis of bone stress distribution around the implants using FEM.
在一些使用多个牙种植体的治疗中，种植体被植入骨骼中，使用带桥或不带桥的种植体修复体。有一些关于使用有限元法（FEM）对带桥和不带桥种植体对骨内应力分布影响的报告，文献中存在争议，即带桥或不带桥种植体修复体是否更有效地减少种植体周围骨产生的应力。此外，许多研究在 FEM 分析中使用了形状简单且骨量有限的颌骨，牺牲了精确分析。
本研究旨在评估带桥和不带桥种植体以及部分和完全无牙颌骨之间骨内应力分布的差异。
将种植体插入部分和完全下颌的第一前磨牙、第二前磨牙和第一磨牙区域，并将带桥和不带桥的牙冠连接到种植体上。在第一前磨牙上施加垂直载荷（100 N）或斜向载荷（70 N，从其长轴向舌侧倾斜 30°）。
当垂直载荷施加于部分缺牙下颌模型时，无论使用带桥还是不带桥种植体，应力都集中在第一前磨牙周围的皮质骨上。另一方面，完全无牙下颌模型上施加的垂直载荷导致不带桥种植体周围的第一前磨牙皮质骨上的应力集中。对于斜向载荷，仅在不带桥种植体的情况下，部分和完全下颌中的第一前磨牙周围的皮质骨上的应力才会集中。
本研究表明，部分和完全下颌骨中种植体周围皮质骨的应力分布不同。这表明，在使用 FEM 分析种植体周围骨的应力分布时，应使用完全下颌骨。
