Comparative Study Of Biomechanical Characteristic For Overdentures Retained With Two Magnetic Attachments By Photoelastic Methods

By comparing the biomechanical characteristic of overdentures retained with Magsoft and Magnedisk magnetic attachments, to evaluate the applied effect of Magsoft magnetic attachments (cushion type) and to provide theoretical guild for clinical application. In this study photoelastic analysis was used to compare the stress distribution for overdentures retained with two magnetic attachments and supported by roots or implants, under vertical and oblique loads. The following results was indicated: 1. The overdentures retained with Magsoft can decrease the stresses around the abutments under vertical loads besides under oblique loads. Magsoft magnetic attachment is of better biomechanical characteristics than Magnedisk and can distribute stresses more evenly throughout the whole supporting structures for its special cushioned design. 2. Compared to Magnedisk, the stresses around the abutments under the overdentures retained with Magsoft were distributed less and in a more evenly manner. It will be very useful to buffer the stress around the roots and bring benefits to the health of remained roots. 3. Overdentures supported by implants need pay more attention to the design of super-structure because the implant-bone interface is easier to be injured than roots. Especially, Magsoft is of great significance for the overdentures supported by implants. 4. For overdentures retained with Magsoft, there are lower stresses around abutments, meanwhile there are higher stresses in the posterior edentulous area. Magsoft has a broader application in clinical work, but it must be well considered for compromised alveolar bone. 5. There are higher stresses concentrated around abutments under oblique loads, so it needs more consideration to buffer the oblique loads. It抯 suggested that the use of magnetic attachments should be a first choice because of their "stress- breaking"feature.