Author/Authors :
Mahshid, Minoo Department - Dental School, Shahid Beheshti University of Medical Sciences, Tehran , Geramy, Allahyar Department of Orthodontics - Tehran University of Medical Sciences, Tehran , Ejlali, Massoud Department - Dental School, Shahid Beheshti University of Medical Sciences, Tehran , Sedaghat Monfared, Majid Department - Dental School, Shahid Beheshti University of Medical Sciences, Tehran , Rezvani Habib Abad, Shirin Department - Dental School, Qazvin University of Medical Sciences, Qazvin
Abstract :
Objective: The main goal of this study was to evaluate differences in stress distribution relevant to the number of implants under an anterior bridge when combined with a remov- able partial denture in the posterior region.
Materials and Methods: Four three-dimensional finite element models (3D FEM) were designed from a mandible containing an implant-supported bridge extending between ca- nines, and a bilateral distal extension removable partial denture. A nonrigid connection was selected as the attachment method between the partial denture and the anterior im- plant-supported fixed prosthesis; 2, 3, 4 and 5 implants supporting the bridge all with 10mm length and 3.8 mm diameter were assessed. With the aid of the finite element pro- gram ANSYS 8.0, the models were loaded and von Mises stresses were evaluated. Results: In spongy bone, stress forces showed a decrease from 2 implants to 4 implants but showed an increase in the 5-implant model. Stresses on cortical bone of terminal im- plants were in similar range in the 2-, 3- and 4-implant models. While, in the 5-implant model the amount of stresses on terminal implants increased dramatically. The stresses on implants were nearly similar in all models, with the greatest amount on terminal implants. Conclusion: Within the limitations of this study, 2-, 3- and 4-implant models showed less stress on cortical and spongy bone in comparison with the 5-implant model. The stresses transferred to implants were nearly similar.
