Retentive force of magnetic attachments applied to the proximal surface–Part 2–

 

Y. Miyama, Y. Mizuno, D. Okano*1, F. Tsuchida*1, Y. Takayama*1, N. Takishin*1, M. Abe*1, C. Ohkubo*1 and T. Hosoi*2

 

Dental Technician Training Institute, Tsurumi University School of Dental Medicine

*1 Department of Removable Prosthodontics, Tsurumi University School of Dental Medicine

*2 Tsurumi University

 

Abstract

 

Purpose: The efficiency of magnetic attachments applied on the proximal surface of abutment teeth has been evaluated. The purpose of this study was to investigate the effects of the placement angles of the keepers and the location of loading points on retentive force.

Materials and Methods: A model of a free-end saddle was employed with the mandibular first premolar as abutment. Using PHYSIO MAGNET 35 (Nissin Co.), keepers were fixed on both the mesial and distal surfaces of the abutment teeth. The fixation angles of both keepers were 2˚, 4˚ or 6˚ to the direction of removal. After magnetic assemblies were fixed to the framework, retentive force was measured by tensile testing and tensile load was placed on five points, namely, the central and the distal points of the abutment tooth, the second premolar, and the first and second molars regions.

Results and Conclusion: The location of loading points had little effect on the retentive force. When magnetic assemblies were applied on both proximal surfaces of the abutment tooth at placement angles of 2˚and 4˚, adequate retentive force could be obtained. The effect of a mechanical interlocking was observed when the placement angle of the keepers was small.