Attractive Force Analysis of Implant Magnetic Keeper using Three-Dimensional Finite Element Method

- The effect of surface screw hole pattern design for magnetic attachments -

H. Kumano, T. Masuda, Y. Nakamura, R. Kanbara, T. Iwai, Y. Ohno, K. Yoshihara,　Y.Tanaka

Department of Removable Prosthodontics, School of Dentistry, Aichi-gakuin University

Abstract

The clinical applications of magnetic attachments with implant overdentures has become more common with progressive advances in implant materials and methods of use. The use of the magnetic attachments non-mechanical retentive design and an ease of concealment helps to reduce lateral forces and results in the controlled load transfer to a supporting abutment. The application and use of magnetic attachments with dental implants permits prosthetic flexibility in implant location and orientation, helping the overall esthetic outcome.

An implant magnetic attachment is secured to a implant fixture using a retaining screw. All screw designs require a superior surface access hole on the the magnetic keeper for placement and removal. These keeper screw access holes used may be of different dimensions depending upon the proprietary instrument size requirements for each design. Few studies are available regarding the influence of a screw hole on attractive force. The finite element method is an effective method for the solution of problems with non-linear material behaviors. The dynamics of a magnet interior is visualized by using this method, and permits simulation under changing conditions.

The purpose of the present study was to analyze the effects of differential screw access hole dimensions to an implant keeper upon attractive force and magnetic field using the three-dimensional (3D) finite element method.