2010 Volume 23 Issue 1 Pages 42-47
Purpose: The keeper surface of a conventional manufactured magnetic attachment for implants normally faces perpendicularly toward the long axis of the implant. Hence, the keeper surface is not parallel to the occlusal plane if the implant is placed at an angle. In such cases, the keeper makes a large undercut and thus, the retentive force decreases. A trial magnetic keeper cap that can be connected to an angled abutment on the implant has been developed. The attractive force of the angled magnetic attachment was compared to that of the conventional keeper.
Methods: In order to fit the Multi-Unit Abutment (Replace RP, Nobel Biocare, Sweden), a trial magnetic keeper (4.8 mm dia., 3 mm high) was milled with stainless steel (72.0%Fe-26.0%Cr-2%other). The trial keeper was connected to a 17- or 30-degree angled Multi-Unit Abutment with a screw. As a control, a Physio Magnet keeper #40 (Hitachi Metals, Japan) was prepared. After a magnet assembly (Physio Magnet #40, Hitachi Metals) was attached to each keeper, they were mounted on a screw-driven tensile machine with a Digital Force Gauge (Nidec-Shimpo Corp., Japan). The attractive force (N) was measured as the maximum tensile force needed to separate the magnet assembly from the keeper. The data (n=5) were analyzed using a t-test at a significance level of α=0.05.
Results: The trial keeper could be easily connected to the manufactured angled abutment using the screw for implant overdentures. There was no significant difference in the attractive force between the trial magnetic keeper and the control (p＞0.05).
Conclusions: The attractive force of the trial keeper was comparable to that of the conventional commercial keeper. This novel keeper has appropriate retention and can be used as a suitable retainer for implant overdentures.
