Finite element stress analysis of implant prosthesis according to platform width of fixture / 대한치과보철학회지

ABSTRACT

STATEMENT OF PROBLEM: With increasing demand of the implant-supported prosthesis, it is advantageous to use the different platform width of the fixture according to bone quantity and quality of the patients. PURPOSE: The purpose of this study was to assess the loading distributing characteristics of two implant designs according to each platform width of fixture, under vertical and inclined loading using finite element analysis. Material and method : The two kinds of finite element models were designed according to each platform width of fixture (4.1mm restorative component x 11.5mm length, 5.0mm wide-diameter restorative component x 11.5mm length). The crown for mandibular first molar was made using UCLA abutment. Each three-dimensional finite element model was created with the physical properties of the implant and surrounding bone. This study simulated loads of 200N at the central fossa in a vertical direction, 200N at the outside point of the central fossa with resin filling into screw hole in a vertical direction and 200N at the buccal cusp in a 300 transverse direction individually. Von Mises stresses were recorded and compared in the supporting bone, fixture, and abutment screw. RESULTS: The stresses were concentrated mainly at the cortex in both vertical and oblique loading but the stresses in the cancellous bone were low in both vertical and oblique loading. Bending moments resulting from non-axial loading of dental implants caused stress concentrations on cortical bone. The magnitude of the stress was greater with the oblique loading. Increasing the platform width of the implant fixture decreased the stress in the supporting bone, fixture and abutment screw. Increased the platform width of fixture decreased the stress in the crown and platform. CONCLUSION: Conclusively, this investigation provides evidence that the platform width of the implant fixture directly affects periimplant stress. By increasing the platform width of the implant fixture, it showed tendency to decreased the supporting bone, fixture and screw. But, further clinical studies are necessary to determine the ideal protocol for the successful placement of wide platform implants.