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.

Influence of Coating Material Thickness on the Attraction Force of Dental Magnetic Attachment: An In Vitro Study

“…In this context, the assembly and keeper in all groups were attached to aluminum rods using cyanoacrylic adhesive and then mounted onto a universal testing machine (UTM; Llyod LRX-Plus 5 kN, Ametek Inc., United Kingdom). The keeper was positioned on the lower UTM arm and the assembly was placed on the upper arm, each with a length of 1 cm [4]. The tensile test was conducted at a cross-head speed of 50 mm/min, and the maximum load value was taken [3,[13][14][15][16].…”

“…DMA replacement in patients due to corrosion is inefficient. Despite coating the DMA with stainless steel, the risk of corrosion persists [ 3 , 4 , 6 ], suggesting the need for extra protection because the attachment is often placed in a corrosive oral environment.…”

“…The disadvantages of DMA include the possession of relatively low retentive force among other attachment types and susceptibility to corrosion, necessitating magnet replacement [1]. Previous studies showed the tendency of magnets to experience corrosion, which would trigger attraction force decline [2][3][4][5]. The production of overdentures with magnetic attachment is a time-consuming and costly process.…”