Three-dimensional finite element analysis of the different crown-root ratio of implant-borne prothesis in repairing the first molar of mandibular

Objective To compare the stress distribution on bone tissue around the implant denture with different crown-root ratio in repairing the first molar of mandibular. Methods Taking Dentium planting system with platform transfer structure of Korea as a reference , draw 5 groups of three-dimensional model which contains the corresponding base station , the central screw and porcelain crown with different crown-root ratio ( 11.5 , 11 , 1.51 , 21 , 31 ) through 3D mapping software of PRO / E Wildfire 5.0. Take vertical and oblique loading on each model. Ansys Workbench13.0 was used to compare Von Mises stress distribution and the trend of stress changes of each model. Results With the vertical load , in any model with different crown-root ratio , the stress concentration appear in the neck , base stations , the central screw and crown of the plant , which are uniform in the overall stress distribution and few significant changes appeared in the Von Mises stress peak of the implant. With the oblique load , the maximum value of Von Mises stress increased significantly in each model , especially in the lip and cheek side of the neck of the plant , cortical bone , base stations , the central screw and crown. With the crown-root ratio increasing , the peak stress of each parts increased significantly. Conclusion The platform conversion effectively transfers the concentration area of stress in the interface between implant and bone , and reduces the absorption of alveolar bone , but it increases risk of loose and broken base stations and central screw.