Powerful “rare-earth” dental magnets

New magnets developed for the Japanese auto industry hold promise for struggling denture wearers.

Dr. Ross Bryant is an assistant professor in Oral Health Sciences and the prinicipal investigator of this research, and. Dr. Michael MacEntee is a professor of in Oral Health Sciences Both work in UBC’s Faculty of Dentistry in the Division of Prosthodontics and Dental Geriatrics..

The scourge of tooth loss is decreasing, but it’s not gone yet. There are still many people who have lost their natural teeth and live to struggle with dentures.  Some manage well but others suffer with little relief.

The first relief came from Sweden about 25 years ago with the discovery of titanium-metal implants embedded with reasonable predictability into the jaws. The future seemed much brighter for denture-wearers, although the mechanism of attaching the dentures to the implants for maximum comfort remained a challenge. Small metal screws were the obvious solution to try, but only if there were enough implants to support the denture completely. Besides, implants are expensive, which limits the number to one or two for many people.

And how could a denture be attached to one or two implants? With difficulty. Metal and plastic clips are available to clip the denture onto a bar that runs between two implants. However, the bars and clips are expensive, bulky and difficult to clean. The denture can be made with a small rubber or plastic ring that clips onto a metal or plastic stud in the implant, although studs wear out and the denture loosens, or they protrude annoyingly into the mouth when the denture is not worn.

So what about magnets? Indeed, dental magnets have been tried with dentures, but they corrode in the mouth and gradually break apart. This was until recently when, as an off-shoot from the automobile industry in Japan, tiny, powerful “rare-earth” magnets protected within small metal containers from corrosion were adapted to fit into dentures. The magnets connect with a strong magnetic force to a small metal “keeper” attached to each implant.

The benefits for denture-wearers are very encouraging to researchers in the faculty of Dentistry at UBC who are testing the magnets in a clinical trial approved by Health Canada. The results since December 2006 look very good. None of the magnets has corroded. Most of the denture-wearers in the trial are satisfied with the results because the magnets have not lost their magnetism, while the “keepers” on the implants are easy to clean, and comfortably smooth against the tongue and cheeks when the denture is out of the mouth.

It is still too soon to say how long the magnets will function comfortably and securely, or resist corrosion. Nonetheless, the progress is promising, and the struggle with dentures may be on the wane.