| Object: Use the finite-element method to give the mandibular fracture with miniplates fixation a biomechanical study, explore the number and the putting position of the miniplates that used, evaluate the effect of the fixation methods, so as to provide theoretically direction for the miniplate clinical use in the mandibular fracture.Methods: Establish the three dimensional finite element models ofmandibular fracture with all kinds of rigid internal fixation (RIF) through modifying the three dimensional finite element model of mandible. Then use the computer to analysis the stress distribution and the mobility of fracture segment in mandibular symphysis,body and angle fractures with miniplates fixation under different occlusion conditions, so as to evaluate the effect of the fixation methods.Result: 1 , The three dimensional finite element models of mandibularfracture with all kinds of rigid internal fixation were established.2,When the mandibular symphysis fracture was fixed with single lower or single upper plate (miniplate) , the mobility of the fracture segment under central occlusion is 0.212586mm and 0.156475mm. When the mandibular body fracture fixed with single lower plate, the mobility of the fracture segment under central occlusion and the occlusion of molar of fracture side is 0.196mm and 0.159mm; When fixed with single upper plate, the mobility of the fracture segment under occlusion of molar of fracture side is 0.176mm. When the mandibular angle fracture fixed with single plate at the external oblique line, the mobility of the fracture segment under occlusion of molar of fracture side is 0.15806mm.3 ,When the mandibular body fracture is under the premolar and molar of fracture side occlusion , the mandibular angle fracture is under the molar of fracture side occlusion , the stress of the upper fracture part is bending force and the lower is compressing force.Conclusion: K The methods that establish the three dimensionalfinite element models of mandibular fracture with rigid internal fixation have more advantage than the methods before, which not only simplify the model-established steps, but also improve the models' geometry and biomechanical comparability. The models have great exploitation and application value.2 > When the 4 holes miniplate apply to the mandibular symphysis fracture, the mobility of the fracture segment under central occlusion are beyond the permission range with single lower or single upper plate fixation. The mandibular symphysis fracture should be fixed by two plates at the upper and lower region.3 , When the 4 holes miniplate apply to the mandibular body fracture, the mobility of the fracture segment under central occlusion and the occlusion of molar of fracture side with single lower plate fixation are beyond the permission range; the mobility of the fracture segment under the occlusion of molar of fracture side with single lower plate fixation are beyond the permission range . The mandibular body fracture should be fixed by two plates at the upper and lower region.4> When the 4 holes miniplate apply to the mandibular angle fracture, the mobility of the fracture segment under occlusion of molar of fracture side with single plate fixation at the external oblique line is beyond the permission range. The mandibular angle fracture should be fixed by two plates at the external... |
