[Mechanical studies on dental magnetic attachments].
The purpose of this study is to investigate the force distribution when using magnetic attachments in removable partial denture. The experimental magnetic attachments used in this study consisted of Nd-Fe-B magnets covered with permendur yokes and permendur keepers. The magnetic parts were attached to the experimental plate which was made of a titanium plate and an acrylic resin base, while the keepers were attached to the abutment teeth. The retentive force was measured by pulling the experimental plate vertically and diagonally with a tensile testing machine. In addition, the three-dimensional stress distribution of the abutment was analyzed by the finite element method when the magnetic attachment was removed. The results were as follows: 1. The maximum retentive force of the plate was influenced by the total of the attractive force, while the minimum force was by the number and arrangement of the attachments. 2. In almost all cases, the magnetic attachments worked most effectively when their attractive force was the same for each other. 3. When the pulling force was vertically applied to the abutment, the maximum stress arose in the alveolar bone around the root tip, and, when the force was laterally applied, the maximum stress arose on the axis of the 1/3 upper portion of the root.
Ishikawa
S
S
First Department of Prosthodontics, Faculty of Dentistry, Tokyo Medical and Dental University.
D001696:Biomechanical Phenomena; D003781:Denture Retention; D003832:Denture, Partial, Removable; D006801:Humans; D008280:Magnetics; D013314:Stress, Mechanical