Comparison of the Attractive Forces of Dental Magnetic Attachments Fabricated by Cast- and Direct-Bonding Techniques

Purpose: This study evaluated the effect of the method of keeper fabrication on the attractive force of the magnetic attachment.Methods: The attractive forces of the keepers of a Hyper Slim 3513 magnetic attachment system (Neomax Material Co. Ltd., Osaka, Japan) and Physio magnetic attachment system 35 (Nissin Co. Ltd., Kyoto, Japan) were measured. Specimens were prepared by the cast-bonding (n=5) and direct-bonding (n=5) techniques. The attractive force was measured using a digital force gauge (FGC-1, Nidec-Shimpo Corporation, Kyoto, Japan). The attractive force was statistically analyzed by the t-test at a significance level of α=0.05.Results: The direct-bonding technique yielded a keeper with significantly greater attractive force than that of the keeper obtained by the cast-bonding technique (P<0.05).Conclusion: Measurement of the attractive force of magnetic attachments fabricated by two different techniques revealed that the magnetic attachment fabricated by direct bonding possessed a significantly greater attractive force than that fabricated by cast bonding. Our results and those of previous studies suggest that the flatness and smoothness of the keeper surface may influence the attractive force of the magnetic attachment.