Biomechanical Analysis In The Initial Stage Of Implantal Distraction

Together with the development of distraction osteogensis, more and more attention is paid to the implantal distractor. But the stress variation of surrounding bones in distraction after the distractor is implanted isn't much clear now. This restricted the clinical application of implantal distractor. In this study, the technology of 3D finite element was applied, and the purpose of this study is meant to guide the clinical use of distractor.First, a program that can generate CAD models in batches was compiled with the language of Visual Basic for Application. The program was running under the environment of Autodesk Mechanical Desktop 2004 DX. The models that the program generated were used in the subsequent experiment. In the following study, the relationship of bone quality, the dimension of transportable bone and the diameter of the distractor to the stress and deformation of bones were investigated. The results are:1. Bone quality influenced the distribution of stress in bone-distractor complex. The maximum equivalent stress occurred in different position as the bone quality varied. As the bone quality decreased, the maximum equivalent stress and deformation increased. This would lower the initial stability of distractor.2. The increase of the length and width of transportable segment would lead to noticeable augment of the maximum equivalent stress of bones, the subsidence of the bone segment and distractor were also increased. Width affected the result more greater than length.3. The diameter of the distractor influenced the stress distribution greatly. In narrow alveolar ridge with better bone quality, excessive enlargement of the diameter of distractor would proliferate the maximum equivalent stress of the transportable segment. Usually, augment of the diameter of distractor would improve the stress distribution of the complex, decrease the range-of-motion of the distractor and transportable segment, and increase the stability of distractor.4. Clinically, modus operandi and distractor should be chosen reasonable Based on the foregoing conclusions.