Chowdhary Ramesh, Halldin Anders, Jimbo Ryo, Wennerberg Ann
Department of Prosthodontics, Faculty of Odontology, Malmö University, Malmö, Sweden.
Clin Implant Dent Relat Res. 2015 Jun;17(3):562-9. doi: 10.1111/cid.12143. Epub 2013 Aug 27.
To describe the early bone tissue response to implants with and without micro threads designed to the full length of an oxidized titanium implant.
A pair of two-dimensional finite element models was designed using a computer aided three-dimensional interactive application files of an implant model with micro threads in between macro threads and one without micro threads. Oxidized titanium implants with (test implants n=20) and without (control implants n=20) micro thread were prepared. A total of 12 rabbits were used and each received four implants. Insertion torque while implant placement and removal torque analysis after 4 weeks was performed in nine rabbits, and histomorphometric analysis in three rabbits, respectively.
Finite element analysis showed less stress accumulation in test implant models with 31Mpa when compared with 62.2 Mpa in control implant model. Insertion and removal torque analysis did not show any statistical significance between the two implant designs. At 4 weeks, there was a significant difference between the two groups in the percentage of new bone volume and bone-to-implant contact in the femur (p< .05); however, not in the tibia.
The effect of micro threads was prominent in the femur suggesting that micro threads promote bone formation. The stress distribution supported by the micro threads was especially effective in the cancellous bone.
描述早期骨组织对带有和不带有沿氧化钛种植体全长设计的微螺纹种植体的反应。
使用计算机辅助三维交互式应用文件设计了一对二维有限元模型，一个是在宏观螺纹之间带有微螺纹的种植体模型，另一个是没有微螺纹的种植体模型。制备了带有微螺纹（测试种植体n = 20）和不带有微螺纹（对照种植体n = 20）的氧化钛种植体。总共使用了12只兔子，每只兔子植入4个种植体。分别对9只兔子进行种植体植入时的插入扭矩和4周后取出扭矩分析，对3只兔子进行组织形态计量学分析。
有限元分析显示，测试种植体模型中的应力积累较少，为31Mpa，而对照种植体模型中的应力积累为62.2Mpa。两种种植体设计之间的插入和取出扭矩分析没有显示出任何统计学意义。在4周时，两组在股骨中的新骨体积百分比和骨与种植体接触方面存在显著差异（p < 0.05）；然而，在胫骨中没有差异。
微螺纹在股骨中的作用显著，表明微螺纹促进骨形成。微螺纹支持的应力分布在松质骨中特别有效。
