Objective: To photoelastically investigate the difference in load distribution of Tension More (TM) implants with different conical angle designs.
Methods: The following five groups of implants of different conical angles were designed: cylinder implant, upper 1/3 TM implant (taper length of 3 mm); 1/2 TM implant (taper length of 5 mm); lower 1/3 TM implant (taper length of 7 mm); and bottom TM implant (taper length of 10 mm). The implants were centrally located in individually photoelastic models consisting of a simulated trabecular bone and a 1 mm-thick layer of cortical bone. Vertical and 45° oblique static loads were applied at the center of the superstructures. The resulting stresses were monitored photoelastically and recorded photographically. RESULTS With vertical loading, the cylinder implant showed higher stress levels in the cortical bone and trabecular bone than the upper 1/3 TM implant, 1/2 TM implant, and lower 1/3 TM implant. The four groups of TM implants showed lower stress levels in the cortical bone than the cylinder implant under oblique loads. The least favorable stress concentration in cortical bone was observed in the upper 1/3 TM implant under vertical and oblique loads.
Conclusion: TM implants of rational conical angle designs seem to be effective in stress distribution. For all designs and load directions, the upper 1/3 TM implant is the most favorable around the crest.
目的: 研究不同锥度设计的Tension More（TM）种植体对种植体骨界面应力分布的影响。
方法: 医用纯钛制作5组种植体，分别为圆柱状螺纹种植体、上1/3 TM种植体（锥度长度为3 mm）、中1/2 TM种植体（锥度长度为5 mm）、下1/3 TM种植体（锥度长度为7 mm）、全长变化TM种植体（锥度长度为10 mm）。每组种植体各自包埋于由松质骨及1 mm皮质骨构成的复合光弹模型中，共建立5个复合光弹模型。每一模型先后分别予以垂直及斜向（45°）静态加载力。利用光弹应力分析法比较5组种植体骨界面的生物力学特征。
结果: 垂直加载下，上1/3 TM种植体、中1/2 TM种植体、下1/3 TM种植体比圆柱状螺纹种植体在皮质骨区及松质骨区的局部应力集中小；斜向加载下，4组TM种植体皮质骨区局部应力集中均低于圆柱状螺纹种植体。无论在垂直、斜向加载下，上1/3 TM种植体皮质骨区局部应力集中均最小。
结论: 合理锥度设计的TM种植体周围皮质骨、松质骨应力分布均匀合理，在不同载荷条件下，上1/3 TM种植体骨界面生物力学表现最优。