These Scientists Created a Controversial ‘Weight-Loss Device’ that Locks People’s Jaws Shut

Within hours of the apparatus being announced on Twitter, detractors were lashing out, with some calling the device “evil.”
Gavin Butler
Melbourne, AU
DentalSlim Diet Control
The DentalSlim Diet Control uses magnets to prevent the wearer's jaw from opening more than two millimetres. Photo via University of Otago.

Researchers are facing backlash over a “world-first weight-loss device” that forces people to stick to liquid diets by locking their jaws shut.

The DentalSlim Diet Control, developed by researchers at New Zealand’s University of Otago, is a magnetic contraption fitted to patients’ upper and lower back teeth that uses locking bolts to prevent them from properly opening their mouths – and, in turn, eating solid foods.


“It allows the wearer to open their mouths only about 2mm, restricting them to a liquid diet, but it allows free speech and doesn’t restrict breathing,” the University of Otago said in a media release on Monday. “Participants in a Dunedin-based trial lost an average of 6.36kg [about 14 pounds] in two weeks and were motivated to continue with their weight loss journey.”

People Are Making a Fortune Off Your Teeth

Professor Paul Brunton, lead researcher for the DentalSlim Diet Control and Pro-Vice-Chancellor at University of Otago’s Division of Health Sciences, noted in the same statement that the device is fitted by a dentist, can be released by the user with a special tool in case of an emergency, and can be repeatedly installed and removed. It represents, in his words, “a non-invasive, reversible, economical and attractive alternative to surgical procedures.”

“The fact is,” Professor Brunton said, “there are no adverse consequences with this device.”

Many disagreed. Within hours of the University of Otago announcing the apparatus on Twitter, detractors were lashing out at it, with some calling the device “evil,” “hateful” and “disturbing.” Others pointed out that obesity is often the product of complex factors including biology and socioeconomic disadvantage, and not something that can be resolved by simply clamping people’s mouths shut. More than a handful described the DentalSlim Diet Control as a “torture device.”


The University of Otago Twitter account has since backpedalled, posting several follow-up tweets that sought to better explain their position.

“To clarify, the intention of the device is not intended as a quick or long-term weight-loss tool; rather it is aimed to assist people who need to undergo surgery and who cannot have the surgery until they have lost weight,” the University claimed. “After two or three weeks they can have the magnets disengaged and device removed. They could then have a period with a less restricted diet and then go back into treatment. This would allow for a phased approach to weight loss supported by advice from a dietician.”

This may also be the reason they’re calling it a “world-first” device in spite of the fact there have been numerous similar contraptions since as far back as the Middle Ages – more recently as a controversial and extreme method of attempted weight loss in countries such as Nigeria and South Africa.

The University of Otago’s own media release points out that the practice of surgically wiring people’s jaws shut became popular in the 1980s, but notes that in those cases it “came with risks” – including the danger of choking on vomit, gum disease, ongoing issues with jaw movement and acute psychiatric conditions. Initial clinical findings for the DentalSlim Diet Control, meanwhile, indicated that “participants had trouble pronouncing some words and felt tense and embarrassed 'only occasionally' … [and] 'hardly ever' reported a change in taste sensation or felt uncomfortable drinking.”

The paper conceded that participants indicated they “occasionally had discomfort and felt that life in general was less satisfying,” but concluded overall that participants “tolerated the device for a two-week period with satisfactory weight loss.”

Professor Brunton did not immediately respond to a request for comment.

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