Abstract     

 The size of a magnetic attachment has become smaller in recent years, and the clinical applications have become more common. However, the method of attaching a ready-made keeper to a root cap is often unavailable due to a lack of space. Arbitrary-shaped keepers were fabricated using castable magnetic alloy to solve this problem. Although hearth of castable dental alloy is commonly used in clinical practice, no reports are available regarding a change in attractive force by using a hearth for casting. The present study investigated an influence of recasting a hearth on attractive force. Samples with different hearth ratio were fabricated. Attractive force, Co content in samples, and segregation were measured to evaluate the correlation. A significant correlation was found between the hearth ratio and Co content, attractive force and Co content, and attractive force and segregation.