Analysis Of Mechanical Properties Of V-Bends By Three Dimensional Finite Element Method

Objective:To analyze the mechanical properties of V-bends with different materials and dimensions of archwires,different shapes and angles,and different interbracket distances by using finite element method which can simulate the clinical process of V bend loading by simulate calculating to provide reference for clinical practice in order to use V-bend pesticide safely and appropriately.Methods:1.Construct solid model of V bend including brackets and ligations with different dimensions(0.017×0.025inch、0.019×0.025inch),different position of apex(a/L=0.5、a/L=0.33)and different angles(150°、165°)and different interbracket distances(7mm、10mm)totaling 16 models with STEP format by combination of two.2.Assemble the V-bend solid models and guide them into the CADfix7.0 software to repair the models.Delete the duplicate point and link the miss surface and so on,Then export the solid models with IGES formate after reparing.3.Assemble the solid models and import them by group into the MSC.Patran software to automatic and manual finite element mesh generation,and then export the models with IGES format.4.Set the physical parameter of IGES format model with two archwires materials totaling 32 working conditions which can simulate the clinical process of V bend loading by simulate calculating of every working conditions.5.Simulate the force load of V-bend by using MSC.Marc.Mentat software by setting different boundary and material properties.Record the reaction forces of the force point with different V-bend,and draw the curves of load to time and maximum force histograms.Results:1.Construct 3-D finite element model of V-bend including brackets and ligations,which can effectively simulate the clinical process of V-bend.2.The result of V-bend with different archwires materials loading;The force trend is similar,and force of SS Groups was greater than TMA,and the ration of two materials was greater when the symmetrical V-bend angle was 150°.3.the maximum force of 0.019×0.025 inch group was greater than 0.019×0.025 inch group by contracting two different dimensions of V-bend.The ratio of two group of symmetrical V-bend was greater than asymmetric V-bend.4..The result of V-bend with different inerbracket distances loading was the force of 7mm group greater than 10mm group,and the ration of two distances of symmetrical V-bend was greater than asymmetric V-bend.5.Contrast of the different shapes V-bend,for the asymmetric V-bend,the force of right canine bracket less than the right second premolar bracket initially,then greater than right second premolar bracket.For asymmetric V-bend the right canine bracket was always less than the right second premolar bracket.The ration of two brackets of symmetrical V-bend indicated the force of right canine bracket similar to the right second premolar bracket,and force of the right canine bracket of asymmetric V-bend was less than the right second premolar.6.Contrast the maximum force of the different shapes V-bend,the right canine bracket of symmetrical V-bend was greater than the right second premolar bracket,in contrast the right canine bracket of the asymmetric V-bend was less than the right second premolar bracket.Conclusion:1.The method constructing V-bend finite element models to analyze the V-bends with different materials and dimensions of archwires,different shapes and angles,and different interbracket distances was a reliable method.2.The force of V-bend group with SS archwire was greater than TMA group at the whole period,and when the angle of symmetrical V-bend was small,the difference of the V-bend with two materials was more significant.3.The force of V-bend group with 0.017×0.025inch dimension was less than 0.019×0.025 inch group at the whole period,and when the shape of V-bend was symmetrical,the difference of the V-bend with two dimensions was more significant.4.The force of V-bend group with 7mm inter bracket distance was greater than 10mm inter bracket distance group,and when the shape of V-bend was asymmetrical,the difference of the V-bend with two dimension was more significant.5.When the shape of V-bend was symmetrical,the force of the right canine bracket was greater than the right second premolar bracket.When the shape of Ⅴ-bend was asymmetrical,the force of the right canine bracket was less than the right second premolar bracket.The force ratio of the right canine bracket and the right second premolar bracket was significantly influenced by the shapes of V-bend,which has little relationship with angles of V-bend.