The Influence of the Screw Hole on the Implant Magnetic Keeper Attachment Surface

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

Removable Prosthodontics, School of Dentistry, Aichi-Gakuin University

Abstract

Restorative implant materials and techniques have continued to evolve and improve. The improved variety of magnetic attachments available for implant overdentures has shown variation and difference in their design.

A subtle but important difference in magnetic attachment design may be the method of attachment of an implant magnetic keeper by cementation or screw retention. While cementation may not affect a magnetic keeper’s magnetic potential, the physical differences in keeper retaining screw designs may affect keeper surface magnetic attraction potentials.

A screw hole is located under the fixed keeper in one design method, and cementation may preclude retrievable access. A screw hole in the keeper method may permit easy maintenance. However, the effect upon magnetic potential by the screw hole in the keeper center is unknown. The magnetic circuit of screw hole keeper design may be adversely affected and result in a diminished magnetic force potential.

As a primary experiment, prototype implant keepers with different screw holes were prepared based on commercially available keepers to investigate the influence and effect of a screw hole on a magnetic keeper attractive force.

A decrease in the attractive force was observed in the center-hole and side-hole models compared with the control model without a hole. A significant difference was observed between each sample.