Retentive Force and Magnetic Flux Leakage of Magnetic Attachment in Keeper and Castable Magnetic Alloy

K. Miyata¹，M. Hasegawa¹，Y. Abe¹，T. Azuhata¹，H. Saito¹，M. Morokuma¹，D. Akita¹，

T. Ishigami^1,2

¹Department of Partial Denture Prosthodontics，Nihon University School of Dentistry, Japan

²Division of Clinical Research, Dental Research Center, Nihon University School of Dentistry, Japan

Abstract

The conventional magnetic attachment consists of a magnetic assembly and keeper. Therefore, this attachment is restricted by keeper size in clinic. The use of Attract P (Tokuriki-honten Co) that is new material of castable magnetic alloy for the fabrication of keeper may allow the expansion of magnetic attachment application. This study evaluated the retentive force and magnetic flux leakage of Attract P.

The specimens were 5.0 × 5.0 × 1.0 mm, and combined with magnetic assembly (GIGAUSS D600, GC) for retentive force and magnetic flux leakage testing. Retentive force was measured 5 times at crosshead speed of 5 mm/min in a universal testing machine. Magnetic flux strength was measured using a Hall Effect Gaussmeter. Data was statistically analyzed using a one- way ANOVA, and Tukey’s HSD post hoc test (α = 0.05).

The retentive force of Attract P and magnetic assembly was 60 % of original combination of GIGAUSS D600, and which were significantly low (p < 0.05). The magnetic flux leakage of Attract P and magnetic assembly was significantly higher than original combination (p < 0.05).

In this result shows this castable magnetic alloy is not expected great attractive force to apply for clinical situation.