Biomechanical optimization of the diameter of distraction screw in distraction implant by three-dimensional finite element analysis.

Three-dimensional (3D) finite element models of a posterior mandibular segment and a distraction implant (DI) were created and assembled in this study. The diameter of distraction screw (DS) was set as input variable, ranging from 1.0 to 3.0mm, to analyze the stress and displacement, in order to obtain an optimal outcome of the DI. The results indicate that when the diameter of DS was 2.0mm, the stresses in jaw bone and DS and the displacement of DS reached a relatively low range. The diameter of DS significantly affects the stress distribution in DI and surrounding bone. The present study demonstrates that from clinical and biomechanical points of view, the optimal diameter of DS is 2.0mm.