October 8, 2011 | By | Reply More


Indication: Some metal alloys possess magnetic properties which can be utilized in the retention of overdentures or partial dentures {Fig. 140}.

Materials: Two different alloys are used as magnets in dentistry. These are

  • cobalt-samarium and
  • ironneodymium – boron.

Both of these rare earth magnets have strong attractive forces.

Advantages: There is less need for parallel abutments as a rigid line of insertion is not critical. Furthermore, the technique is simple, involving minimal time at the chair side and in the laboratory.

Disadvantages: Magnets are brittle materials with a low corrosion resistance. Even when encapsulated in stainless steel, titanium or palladium, the coating may wear and the magnetic alloy will come into contact with saliva. The combination of saliva contact and wear has a deleterious effect on the corrosion resistance of the material.

Procedure: The magnets are placed on the replica of the keepers and cured within the denture base material. The overdenture abutments have a cast magnetic alloy post and coping which is placed in the root canal. A direct pick up technique can be used at the chairside where the magnets are directly attached to the denture with autopolymerising acrylic.

The stainless steel capsule containing the magnets must be checked regularly as, if this is breached, the magnet will corrode and lose its magnetic properties.

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Category: Dental, Oral Surgery, Prosthodontics

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