title: The effect of fixture neck design in a realistic model of dental implant: a finite element approach.
abstract: The aim of this work is to develop an accurate finite element model able to reproduce a standard experimental set-up for the evaluation of mechanical failure of a dental implant system. The considered system is composed of a fixture, an abutment and a connecting screw. We analysed the behaviour of the implant system considering three different designs of the fixture, in order to establish which one provides the better mechanical behaviour. After the definition of the numerical models, loading conditions were selected in order to reproduce the same stress state found in previous mechanical failure tests. Preloading and functional loading conditions were simulated. The analysis of the numerical results shows that the structure yielding is due to the fixture neck plastic deformation, that increases the load eccentricity and then the bending stress on the connecting screw. Only slight differences were found between the three implant systems in the amount and distribution of stress. The model reproduces properly the implant systems and the experimental set-up. The goodness of the model can be summarised as: realistic geometrical structure, elastoplastic model for the material description, correct definition of the contacts and the existing tolerance among the different system components, reproduction of the preloading stress condition. The present study permitted to define a valid procedure for the realization of numerical models of implant systems.
authors.forename: Silvia
authors.initials: S
authors.lastname: Necchi
authors.forename: Francesco
authors.initials: F
authors.lastname: Migliavacca
authors.forename: Dario
authors.initials: D
authors.lastname: Gastaldi
authors.forename: Manuela
authors.initials: M
authors.lastname: Pizzagalli
authors.forename: Massimo
authors.initials: M
authors.lastname: Del Fabbro
authors.forename: Roberto
authors.initials: R
authors.lastname: Weinstein
authors.forename: Riccardo
authors.initials: R
authors.lastname: Pietrabissa
authors.forename: Gabriele
authors.initials: G
authors.lastname: Dubini
mesh_terms: D003198:Computer Simulation; D017076:Computer-Aided Design; D015921:Dental Implants; D017267:Dental Prosthesis Design / Q000379:methods*; D019232:Dental Restoration Failure; D019544:Equipment Failure Analysis / Q000379:methods*; D020342:Finite Element Analysis; D008962:Models, Theoretical; D009038:Motion; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D015921:Dental Implants