Corrosion resistance and biocompatibility of a dental magnetic attachment

Abstract

A dental magnetic attachment is used for over-dentures, removable partial dentures, and orthodontic and maxillofacial prostheses. The dental magnetic attachment is composed of a magnetic assembly and a keeper. The magnetic attractive force between the magnetic assembly and the keeper is used as the retention. The magnetic assembly is composed of a small Nd—Fe—B magnet that is covered within a magnetic stainless steel yoke and a non-magnetic stainless steel spacer. The keeper is also made of magnetic stainless steel. The yoke of the magnet assembly and the keeper form a closed magnetic circuit, which is necessary to concentrate on the magnetic flux and make efficient use of it. The covering nonmagnetic stainless steel and magnetic stainless steel yoke are welded seamlessly using micro-laser to protect the magnet from corrosion. In an oral cavity, the keepers and the magnetic assemblies are contacted with root caps made of dental precious alloys. It is important to examine the galvanic corrosion behavior of those stainless steels with dental precious alloys from the electrochemical properties and released ions. The dental magnetic attachment was implanted in rabbit tibia to investigate the influence of the static magnetic flux on hard tissue.