The Effect of Acid Solution on Dental Magnetic Attachment

Abstract

Dental magnetic attachments used as a retainer for overdentures are encapsulated with a corrosion resistant casing to prevent corrosion of magnets. However, some studies reported that the casing still has a risk of corrosion. This study aims to determine the effect of acid solutions on magnetic attractive force, dissolving metal ions and corrosion of magnetic attachment surfaces. The dental magnetic attachment material used is Magfit DX 600 (Aichi, Japan). It consists of assembly and keeper. The assembly and keeper immersed in acid solutions with a pH of 3.8 and 5.8 for 7 and 14 days. After immersion, the assembly and keeper were analyzed using SEM, universal testing machine, and the atomic absorption spectrophotometry to determine the surface corrosion, the magnetic attractive force, and dissolved metal ions, respectively. It is found that all assemblies showed signs of corrosion and reduction of magnetic attractive force after immersed in acid solutions with a pH of 3.8 and 5.8 for 7 and 14 days. A greater decrease in magnetic attraction was obtained at 14 days immersion in an acid solution with a pH of 3.8. Fe ion dissolution in the assembly and keeper was found to increase at 14 days of immersion. The lower the pH of the acid solution and the longer the immersion time, the signs of corrosion on the surface of dental magnetic attachment are clearly observed. The magnetic attraction force also decreased with decreasing the value of pH as well as the increase of the content of Fe ion in immersed solution.