单端固定桥斜向受载三维位移的数字激光散斑技术研究

Study on the Digital Laser Speckle Technique of Three-dimensional Displacement of Cantilever Fixed Partial Denture under Oblique Loading

该实验旨在研究单端固定桥(CFPD)在斜向加载时的位移情况。采用新鲜离体比格犬下颌骨作为实验对象,制作CFPD,首次采用数字激光散斑技术测量CFPD在斜向加载时,不同加载量下的三维位移。结果表明:斜向加载桥体时,整个CFPD出现最大位移量,桥体位移量大于近缺隙侧基牙,近缺隙侧基牙大于远缺隙侧基牙;斜向加载基牙时,相应受载基牙位移量最大,桥体和邻近基牙次之。在斜向加载过程中,随着加载量的增加,位移量也增大。因此,可认为CFPD在使用过程中要避免斜向受力,尤其是桥体的斜向受力。此外,本研究还证实数字激光散斑技术是一种比较适合测量体积小而不规则形态物的三维位移的方法。

The purpose of this study was to investigate the three-dimensional displacement of the cantilever fixed par- tial denture （CFPD） under an oblique loading. One Beagle dog was used in this experiment. The CFPD, which used the second premolar and the first molar as abutments and the second molar as pontic, was made in vitro fresh mandi- ble of the Beagle dog, and the digital laser speckle （DLS） technique was employed to measure the three-dimensional displacement of the CFPD under the oblique loading for the first time. We found that when an oblique loading was exerted on the pontic, the displacement of CFPD was the greatest, and the displacement of the abutment near the pontic was smaller than that of the pontic but greater than that of the abutment far from the pontic. We also found that when an oblique loading was exerted on the abutment, the displacement of the directly loaded abutment was greater than that of the other abutment and the pontic. Under the oblique loading, the displacement increased with increasing of load. The experiment demonstrated that it would be advisable for the clinicians to avoid oblique loading, especially the oblique loading of the pontic when using the CPDF. The DLS technique may be one kind of methods for measuring the three-dimensional displacements of the small and irregular objects.