Finite element analysis on dental implant-supported prostheses without passive fit.
OBJECTIVE
The purpose of this study is to use finite element analysis to investigate the effect of misfit prostheses, cantilever prostheses, and various occlusal forces on the stress distribution in the prostheses, implant components, and surrounding bone.


METHODS
Two 3-dimensional finite element models were constructed: (1) a 2-implant-supported, 2-unit fixed partial denture and (2) a 2-implant-supported, 2-unit fixed partial denture with a distal cantilever. Variations of the standard finite element models were made by placing a 111-microm gap between the gold cylinder on either the mesial or distal implant. The effects of load of 100 N were tested on all models. Subsequently, loads of 50 N, 200 N, and 300 N were evaluated on the cantilever model.


RESULTS
When the gap was positioned near to the applied force, the stress in both models increased significantly in the implant components and surrounding bone. The stress increase in each component ranged from 8% to 64% in the non-cantilever models and 43% to 85% in the cantilever models. The greatest stress was found in the distal gold screw. The effect of the gap was clearly shown by the pattern of stress distribution in both models. Additionally, the presence of a cantilever and excessive occlusal force amplified the effect of prosthesis misfit.


CONCLUSIONS
Prosthesis misfit influenced the pattern and magnitude of stress distribution in the prosthesis, implant components, and surrounding bone, and the presence of the cantilever or greater occlusal force amplified the effect of misfit.
Kunavisarut
Chatchai
C
Department of Prosthodontics, School of Dentistry, University of North Carolina, Chapel Hill, NC, USA. drjub@hotmail.com
Lang
Lisa A
LA
Stoner
Brian R
BR
Felton
David A
DA
D001732:Bite Force; D003198:Computer Simulation; D003442:Crowns; D000044:Dental Abutments; D015921:Dental Implants; D017267:Dental Prosthesis Design; D019094:Dental Prosthesis, Implant-Supported; D003779:Denture Design; D003830:Denture, Partial, Fixed; D020342:Finite Element Analysis; D006047:Gold Alloys / Q000737:chemistry; D006801:Humans; D008334:Mandible / Q000503:physiopathology; D008954:Models, Biological; D013314:Stress, Mechanical; D013499:Surface Properties
D015921:Dental Implants; D006047:Gold Alloys