The Three-dimensional Finite Element Analysis Of The Upper Dentition Retraction With Micro-implant Anchorage In Infrazygomatic Crest

Objective: Observed the trend of tooth move,displacement changes and the occlusal plane change during the upper dentition retraction with micro-implant anchorage in infrazygomatic crest.Expect to provide some instruction in our clinic work.Materials and methods: A adult female volunteer was Choosed as our experiment sample.Scanned the upper jaw bone and maxillary tooth by cone beam computed tomography,completed the three dimensional reconstruction of the image applied Mimics software.After finishing the optimizing process on model,we got the computer-aided design model of the upper jaw bone and maxillary tooth finally, composited with the model of MBT bracket,arch wire and towing hook, we get the model of three dimensional finite element of the upper dentition retraction after meshing generation.Applied the finite element analysis software Abaqus simulated stress application 200 g by micro-implant anchorage proceed the movement of the upper dentition retraction on different height of the towing hook(0,2,4,6,8,10mm) and different width of the arch wire( 0.017*0.025 inch,0.019*0.025inch).To Study the displacement changes of three dimensions about the central incisor,canine teeth and the first molar,including anterior-posterior dimension(dental crowns displacement,dental root displacement),vertical dimension(occlusal plane change)and buccolingual dimension(arch width).Result : When the upper dentition retraction on 0.019*0.025 inch arch wire and the height of the towing hook are the 0,2,4,6,8,10 mm,the displacement of dental crowns about central incisor on anterior-posterior dimension are the 9*10-3,,5*10-3,0,-4*10-3,,-8*10-3,-14*10-3mm,the displacement of dental root about central incisor on anterior-posterior dimension are the0,4*10-3, 7*10-3,11*10-3,14*10-3,17,*10-3mm.the displacement of buccolingual dimension are the 0,,2*10-3,5*10-3,8*10-3,9*10-3,12*10-3mm,the displacement of vertical dimension are the-2*10-3,3*10-3,9*10-3,14*10-3,20,*10-3.the displacement of canine teeth on anterior-posterior dimension are the6*10-3,6*10-3,6*10-3,6*10-3,6*10-3,7*10-3mm,the displacement of dental root of canine teeth on anterior-posterior dimension are the 1*10-3,0,-1*10-3,-2*10-3,-2.5*10-3,-3*10-3mm.the displacement of buccolingual dimension are the 2.8*10-3, 1.2*10-3,-0.4*10-3,-2.1*10-3,-3.8*10-3,-5.4*10-3mm,the displacement of vertical dimension are the 2*10-3,0,-3*10-3,-5*10-3,-7*10-3,-10*10-3mm.The displacement of dental crowns about the first molar on anterior-posterior dimension are the 4*10-3,4*10-3,4*10-3,3*10-3,3*10-3,3*10-3mm,the displacement of dental root about the first molar on anterior-posterior dimension are the-1*10-3mm, the displacement of buccolingual dimension are the 1.2*10-3,0.8*10-3,0.5*10-3,0.2*10-3,-0.2*10-3,-0.6*10-3mm,the displacement of vertical dimension are the 0,0,0,-1*10-3,0,-1*10-3mm.The trend of movement about the central incisor,the canine teeth and the first molar during the upper dentition retraction on 0.017*0.025 inch arch wire are basically coincide with 0.019*0.025 inch arch wire on different height of the towing hook,but the displacement are bigger than on 0.019*0.025 inch arch wire.When the height of towing hook are the 0,2mm, the occlusal plane rotated in clockwise direction.When the height of towing hook are the 4,6,8,10 mm,the occlusal plane rotated in counterclockwise direction.conclusion: 1.The trend of movement about the central incisor,the canine teeth and the first molar during the upper dentition retraction on 0.017*0.025 inch arch wire are basically coincide with 0.019*0.025 inch arch wire.The initial displacement on 0.017*0.025 inch arch wire is bigger than on 0.019*0.025 inch arch wire.The 0.019*0.025 inch arch wire controlled the torque of anterior teeth,occlusal plane and width of arch wire better than 0.017*0.025 inch arch wire.2.Applied low towing hook,the occlusal plane rotated in clockwise direction. Applied high towing hook,the occlusal plane rotated in counterclockwise direction.