Magnet Retained Overdenture
An Implant Supported Denture
Overdentures with magnetic attachments are called “Magnetic dentures“. Magnets have become very popular as retainers since the 1950’s. According to The Times, in 1957, a Cornell University Medical College professor developed a denture that was held in place by embedding powerful magnets in the patients jaw bone. The magnets were made from aluminum–nickle–cobalt (AlNiCo) alloys.

The magnetic power of the magnets is nowadays high enough to retain overdentures of a different kind. Magnet System is a multipurpose system for increasing retention and stabilisation of the overdentures. Magnetic attachments used to retain dentures are typically shorter than mechanical attachments, which is particularly useful for patients with restricted interocclusal (inter-jaw)space and challenging esthetic demands.

Magnetically retained overdentures transfer no detrimental lateral forces to those supporting implant, helps in maintaining favourable clinical situation. The use of magnetic materials as an aid to denture retention is not new. The use of magnets to provide retention by direct attraction followed, with the placement of a magnet beneath the mucosa, embedded in the bone, and the opposite pole magnet in the fitting surface of the denture base. Manufactured from titanium, the locating face has been developed to eliminate surface wear during function.

Advantages of Magnet Over Mechanical Attachments

  • It is easier to insert or remove the denture, as there is no specific path of insertion. This is particularly a bonus for patients with limited dexterity, such as the elderly.
  • In mechanical attachments through the use of bar or ball attachments, it is essential that the abutments are parallel to each other, so that chewing forces are transferred along the long axis of the abutment, and not laterally. If an implant is to be used as an abutment, it has to be parallel to the other remaining teeth and to each other. However, no abutment parallelism is required in magnetic dentures, as retention is achieved through magnetic attraction.
  • Soft tissue undercuts may be engaged
  • There is a reduced lateral force on the abutments with magnetic dentures. Lateral forces can badly influence the supporting teeth or implants.
  • No wear, less maintanence
  • Magnetic attachments used to retain dentures are typically shorter than mechanical attachments. This is an advantage for patients with decreased interocclusal space (the vertical distance between upper and lower jaw).
  • The lifespan of a magnetic force is infinite, which means that the retentive force of a magnetic unit lasts longer than that of mechanical attachments

Disadvantages of Magnetic Dentures

  • Magnets may cause distortion during magnetic resonance imaging (MRI) of the head and neck.  Thus the patients should have their dentures with magnets removed and have the magnetic components (the “keepers”) unscrewed from the implants before an MRI is done on the head and neck. As with most metallic dental materials, there is minimal risk of patient injury through displacement of the keeper component during MRI, provided the keepers are properly attached within the mouth.
  • There have been reports of more plaque collecting around magnetic attachments than around mechanical attachments, for reasons unknown. Hence the patients are always advised to maintain their oral hygiene at their best.

Patient Satisfaction

According to the Journal of the Canada Dental Association (JDCA) dated 16th September 2010, in a 10-year randomized clinical trial, there was no difference in general satisfaction with a magnetic attachment system for retaining lower complete dentures and 2 types of mechanical attachments (ball or bar systems), although the dentures retained by magnets were subjectively less stable and less comfortable than dentures retained by mechanical attachments.