RETENTIVE CHARACTERISTICS OF DIFFERENT DENTAL MAGNETIC SYSTEMS

It is necessary to recognize the retentive capabilities of magnetic sy stems to assess their clinical performance. This study determined the retentive characteristics of one open-field and two closed field comme rcial dental magnetic systems. The effect of speed of separation and t he space between the magnet and its keeper on the retention force were evaluated. The magnets and their respective keepers, embedded in acry lic resin blocks, were tested with fast and slow speeds of separation. The maximum retention values of the magnetic systems were tested with slow speed of separation. The fast speed of separation was designed t o reflect mandibular movement. Various spaces were developed between t he magnets and their respective keepers, and magnetic systems were tes ted only in slow speed of separation. The fast speed of separation dra matically lowered the retention force of each magnetic system. As the space increased between the magnet and keeper, the retention values di minished rapidly. While closed-field systems demonstrated higher reten tive forces than the open-field system, the open-field system was less affected by the various spaces.