| objective:To bulid a finite elements model of Craniofacial Complex which include implants,dentalarch,periodontium,sutures.using biomechanical method.And to evaluate the rotation and movement of the masomaxillary complex under implant protraction in various position of the maxilla bone.The result of this study can direct the clinical when we face different growth pattens.Methods:The original DICOM data of 2-D image craniofacial complex was obtained from healthy man at the age of 17 with a normal occlusion by high resolution CT scanning. To construct a three dimensional geometric model of the craniofacial complex which include dentalarch,periodontium,sutures by the software MIMICS 10.0.MSC according to the original DICOM data. Build the solid model of implant which has the same parameter with the clinical implant by the software ProE 4.0. assemble these models to become one and make it become solid model by the GEOMAGIC STUDIO 10.0.Use the MARC.MENTANT 2005 R3 to make the three dimensional solid model. Simulate the boundary conditions of craniofacial complex protraction with MSC. Marc.Mentat software,fixed the front area of the frontal bone and the margin of the foramen magnum of occipital bone. Design the parameter of the model simulates the clinical:at the top of the implant,forces of 800g are applied with protraction which direction is inclind at 30 to Frankfort horizontal plane in the anterior and inferior directions,three different position of implants were loaded separately. Craniofacial rotation, displacement and the stress distribution are analysised. Data of principle stress,equivalent of stress,equivalent Von Mices stress of each node of each simulaton is caculated.Then the stress nephograms and the diagrams of the displament are protracted. Results:1.3-D geometrical models of craniofacial complex which include implant,dentalarch, periodontium,suture are obtained.The mesh generation is precise and reasonable.2. Under the protraction of different position of the implant anchorage,the maxillary complex show complicated changes of the rotation and displacement. (1)When the implant between the second premolar and the first molar With the directon of the protraction force is inclind at the 30°, the maxillary complex move forward bodily; (2) When the implant between the second premolar and the first molar With the directon of the protraction force is inclind at the 40°, the maxillary complex show counterclockwise rotation; (3) When the directon of the protraction force is inclind bigger than 30°, whereever the position of the implant, the maxillacomplex will show clockwiserotation. Conclutions:1.Apply the combination of Mimics10.0,MSC. Marc.mentat 2005 R3 and geomagic studio 10.0 software to develop 3-D finite element models of craniofacial complex, of which the bone suture,implant,dentalarch and periodontium are also included.2.With the same force of protraction and different angle, and with the different implants position,the maxillary complex interior stress is complex,the stress of different sutures show different changes.3The rotation of the maxillary compex will be more counterclockwise when the position of the implant move to the back of the maxillary complex. When the protraction angle is between30°-40°,implant which between the second premolar and the first molar will make the maxillary complex counterclockwise rotated. When the protraction angle's more than 50°,the three different implants all takeplace clockwise rotation.So when the patient have a tendency of openbite,wo have to put the implant in the front of the maxillary with the protration angle lower than 40°.as possible for preventing the counterclockwise rotation of the maxillary complex. It is unilateral and unreasonablie to discuss the influence of the maxillary protraction if wo do not synthesize the relevant data about angle and position.4 the anchorage of implant is more suite for the patient with the tendency of openbite,because it is more closed to the center of resistance.
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