Threaded versus porous-surfaced implants as anchorage units for orthodontic treatment: three-dimensional finite element analysis of peri-implant bone tissue stresses.
Threaded versus porous-surfaced implants as anchorage units for orthodontic treatment: three-dimensional finite element analysis of peri-implant bone tissue stresses.
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发表时间：
2006-11
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通讯作者：
R. Pilliar;G. Sagals;S. Meguid;R. Oyonarte;D. Deporter
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作者：
R. Pilliar;G. Sagals;S. Meguid;R. Oyonarte;D. Deporter
目的建立三维有限元模型，研究烧结型多孔面和机加工(车削)螺纹牙种植体用于正畸支抗的不同顶骨丢失模式的原因。材料与方法采用节点间抛物线内插的20个节点结构实体单元模拟种植体-骨界面区域。3-N牵引力的2个多孔表面或2个机械螺纹式种植体放置在犬前磨牙下颌部位，以及在正畸加载开始时和22周时观察到的骨形态。结果加工后的螺纹型种植体在初始和最终时间点均预测种植体冠状区附近的种植体周围骨的最大应力较高，比22周加载后的预测值高20%。这些值大约比多孔表面植入物的预测值大200%，对于多孔表面的植入物，预测的应力分布更加均匀。讨论有限元模型结果表明，在多孔表面种植体附近观察到更大的顶骨保持是由于这种设计在种植体周围骨中形成了较低的峰值应力，从而减少了与局部应力过大和骨微骨折相关的骨丢失的可能性。结论预测的较低应力是由于多孔表面种植体将力从种植体更均匀地传递到骨中的结果，这是这种设计可能使骨和种植体互锁的结果。
PURPOSE A 3-dimensional finite element model was developed to investigate the cause of different crestal bone loss patterns observed around sintered porous-surfaced and machined (turned) threaded dental implants used for orthodontic anchorage in a previously reported animal study. MATERIALS AND METHODS Twenty-noded structural solid elements with parabolic interpolation between nodes were used for modeling the bone-implant interface zone. A 3-N traction force acting between either 2 porous-surfaced or 2 machined threaded implants placed in canine premolar mandibular sites and bone profiles observed at initiation and 22 weeks of orthodontic loading were modeled. RESULTS Higher maximum stresses in peri-implant bone next to the coronal region of the implants were predicted with the machined threaded implants at both the initial and final time points, with the values 20% greater than those predicted after the 22-week loading period. These values were approximately 200% greater than those predicted for the porous-surfaced implants, for which a more uniform stress distribution was predicted. DISCUSSION The finite element model results indicated that the observed greater retention of crestal bone next to the porous-surfaced implants was attributable to lower peak stresses developing in crestal peri-implant bone with this design, which decreased the probability of bone loss related to local overstressing and bone microfracture. CONCLUSION The predicted lower stresses were a result of the more uniform transfer of force from implant to bone with the porous-surfaced implants, which was a consequence of the interlocking of bone and implant possible with this design.