Kobari Hiromori, Yoda Nobuhiro, Chen Junning, Kawata Tetsuo, Sasaki Keiichi
Int J Oral Maxillofac Implants. 2016 Sep-Oct;31(5):1049-57. doi: 10.11607/jomi.4554.
The aims of this study were to develop a device for in vivo measurement of three-dimensional (3D) loads on implants and to investigate the effects of implant configuration on the load distribution under a three-unit fixed partial denture (FPD).
A 67-year-old female patient with three implants (in the mandibular left second premolar, first molar, and second molar regions) was recruited. Four implant configurations for a three-unit FPD depending on the number and position of the implants were considered in this study. They included a three-implant prosthesis and three types of two-implant prosthesis: a central pontic, posterior cantilever, and anterior cantilever, with the same superstructure (splinted three crowns) for the same occlusal contact. Customized abutments and 3D piezoelectric force transducers were fixed to the implants of the four configurations with the superstructure. The loads on the implants were recorded during maximum voluntary clenching (MVC-test) and when chewing a piece of chewing gum (GUMtest).
The occlusal forces on the dental arch during MVC-test with the four implant configurations did not exhibit significant differences. In the three-implant prosthesis, there were no significant differences in the mean maximum resultant load on each implant in both tests. In the central pontic, the load on the second premolar was significantly greater than that on the second molar in the MVC-test but there were no significant differences in the GUM-test. High loads were detected on the first molar in both the posterior cantilever and anterior cantilever. The highest load was detected on the first molar in the posterior cantilever during the GUMtest.
The in vivo 3D load-measuring device using the piezoelectric force transducers enabled the measurement of the functional load on implants supporting a FPD. The results suggested, within the limitations of this study, that a three-implant prosthesis and central pontic provide biomechanically beneficial designs compared with the posterior cantilever and anterior cantilever in terms of the equal distribution of loads on supporting implants.
本研究的目的是开发一种用于体内测量种植体三维（3D）负荷的装置，并研究种植体配置对三联固定局部义齿（FPD）下负荷分布的影响。
招募一名67岁的女性患者，其下颌左侧第二前磨牙、第一磨牙和第二磨牙区域有三颗种植体。本研究考虑了根据种植体数量和位置的四种三联FPD种植体配置。它们包括一个三联种植体修复体和三种双种植体修复体：中央桥体、后悬臂和前悬臂，具有相同的上部结构（三个冠连冠）用于相同的咬合接触。定制基台和3D压电力传感器通过上部结构固定到四种配置的种植体上。在最大自主紧咬（MVC测试）和咀嚼一片口香糖（口香糖测试）时记录种植体上的负荷。
在四种种植体配置的MVC测试期间，牙弓上的咬合力没有显著差异。在三联种植体修复体中，两种测试中每个种植体上的平均最大合力负荷没有显著差异。在中央桥体中，MVC测试中第二前磨牙上的负荷显著大于第二磨牙上的负荷，但在口香糖测试中没有显著差异。在后悬臂和前悬臂中，第一磨牙上均检测到高负荷。在口香糖测试期间，后悬臂中第一磨牙上检测到的负荷最高。
使用压电力传感器的体内3D负荷测量装置能够测量支持FPD的种植体上的功能负荷。结果表明，在本研究的局限性内，就支持种植体上负荷的均匀分布而言，三联种植体修复体和中央桥体与后悬臂和前悬臂相比提供了生物力学上有益的设计。
