The physical properties and behavior of magnets used in the treatment of anterior open bite.

This investigation examined the magnetic flux and repulsive force of neodymium-iron-boron (Nd-Fe-B) magnets used in repulsion in the treatment of anterior open bite. Three different grades of magnets each of five different dimensions were used. Magnetic flux was measured by a Hall probe and the repulsive force by an Instron mechanical testing machine. Results showed that the different grades of magnet displayed similar magnetic flux with a relationship between thickness and flux. There was a significant difference between the flux measured at the end as opposed to the center of the magnet. The force between two magnets and the flux above each magnet was directly related. Using magnets in groups did not produce higher forces than using single magnets of an equivalent size. It was concluded that Nd-Fe-B magnets can be used to give predictable repulsive forces in the mouth.