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,
*1 Department of
Removable Prosthodontics,
*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.