[ finite-element analysis of stress distribution around dental implant in different bar-attachment systems]

When implants are used to support an over denture, the optimal stress distribution is desirable to minimize the forces on the implants. The purpose of this study was to compare stress patterns generated around implant supported over denture with two different bar attachment systems ITI [Dolder] and OT with finite element method. In this descriptive study, the stress distribution around dental implants in an edentulous mandible with two different bar attachment systems [OT without spacer and ITI [Dolder] with spacerl was calculated by means of three-dimensional, finite-element model of an entire lower jaw. This model was provided with two endosseous implants in the canine region. The implants were connected to a 2 mm bar height and a vertical force was applied to the first left molar and gradually increased from 0 to 50N. Then, resultant stress distribution was evaluated. In OT and ITI [Dolder] bar attachments, the maximum von Mises stress values were observed in the cortical bone adjacent to the implant neck and this value was higher for OT bar [6.114Mpa] than ITI [Dolder] bar attachment [3.896 Mpa]. This 3-D FE study suggested that the use of ITI [Dolder] bar attachment with spacer is more advantageous than OT bar attachment for implant-supported overdenture with regard to optimizing stress distribution