Biological aspects of the use of permanent magnets and static magnetic fields in Orthodontics.

M.A. Papadopoulos
Hellenic Orthodontic Review 1998;1:145-57.

The purpose of this review was to address the possible biologic effects of the use of permanent magnets and static magnetic fields in orthodontics. In recent decades, the development of new, small and highly effective rare earth magnets, producing static magnetic fields, as well as their potential for multiple applications in orthodontics have significantly increased the interest in their use. The influence of static magnetic fields on osteoblastic activity and orthodontic movement still remains an issue requiring further investigation.
The author examined the effect of static magnetic fields on osteoblastic cell cultures under the influence magnetic fields with an intensity of 178 mT (miliTesla), produced by neodymium-iron-boron (Ne₂Fe₁₄B) magnets. The results of this in vitro study, did not show any influence of static magnetic fields on osteoblastic activity. Today, it is well known that static magnetic fields produced by small, permanent, rare earth magnets used in orthodontics have no harmful effect on tissues or cells. It seems that the better or quicker therapeutic results achieved by some researchers with permanent magnets, are due more to the biomechanical properties of some magnetic systems and less to the biologic effects of magnetic fields. When used in clinical practice, permanent magnets should be plated with biocompatible materials in order to avoid corrosion and toxicity.

Request for reprints:Dr. M.A. Papadopoulos, Lecturer, Department of Orthodontics, School of Dentistry, Aristotle University of Thessaloniki, GR-54006 Thessaloniki, Greece