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Intra-oral device for weight loss ignites discussion about effectiveness and ethics

Researchers have developed an intra-oral device for weight loss that allows the wearer to open his or her mouth only about 2 mm. (Image: Medvid.com/Shutterstock)
By Franziska Beier, Dental Tribune International
July 21, 2021

DUNEDIN, New Zealand: In both developed and developing countries, obesity has become so common that it is being described as a global epidemic. Researchers from the University of Otago in Dunedin and institutions in the UK have proposed a weight loss aid for certain patients in the form of an intra-oral device fitted to the posterior teeth. DentalSlim Diet Control uses magnets to restrict mouth opening, permitting a liquid diet only. While the device has been called a “world-first weight loss device to help fight the global obesity epidemic”, many have expressed their disapproval and concern about it.

Obesity, an excessively high amount of body fat in relation to lean body mass, has serious health risks—approximately 2.8 million people die annually as a consequence of being overweight or obese. It is estimated that 1.9 billion adults are overweight and 650.0 million of these adults are obese and that, by 2030, 57.8% of the adult population is expected to be either overweight or obese.

For this study, seven healthy obese participants (all female) were recruited to wear DentalSlim Diet Control cemented to their first molars for 14 days, during which they received a liquid diet. Follow-up examinations were carried out via a questionnaire after one, seven and 14 days of wearing of the device and two weeks after the device was removed.

DentalSlim Diet Control only permits a liquid diet. (Image: University of Otago)

Within the 14 days of wearing the device, the participants lost an average of 6.36 kg, which represented approximately 5.1% of their body weight. Two weeks after device removal, the participants had regained around 0.73 kg.

As the device allows the wearer to open his or her mouth by only about 2 mm, the participants reported trouble pronouncing certain words and most of them experienced occasional discomfort, mainly due to the friction of the device against the cheeks. A change in taste sensation and discomfort while drinking were seldom reported.

After the first day, the participants indicated that they occasionally felt embarrassed and self-conscious and that “life, in general, was less satisfying”. It was also reported that the device was too bulky and visible so that the wearers could not enjoy social events such as family dinners. Based on these results, the researchers developed a smaller device with better aesthetics that will undergo clinical testing in future studies.

According to the study, all the participants became accustomed to the device and were able to effectively pursue their profession. Analysis showed that they “were happy with the outcome and were motivated to lose more weight”.

For emergencies, for example vomiting, the wearer can open the device with a tool, as the restricted opening of the mouth would otherwise pose a risk of choking. According to the research team, this is an improvement on surgical intermaxillary fixation—a practice which became popular in the 1980s.

“Alternative strategies are required which may obviate surgery, or which reduce weight prior to surgery and so make it easier and safer,” said lead author Prof. Paul Brunton, pro-vice-chancellor of the Division of Health Sciences at University of Otago.

He commented on the device in a university press release: “It is a non-invasive, reversible, economical and attractive alternative to surgical procedures. The main barrier for people for successful weight loss is compliance and this helps them establish new habits, allowing them to comply with a low-calorie diet for a period of time. It really kick-starts the process.”

“This could actually help a lot of people,” he emphasised.

Oral hygiene concerns

The device can be applied by a dentist in about 20 minutes after basic training and is easy to fit and remove, according to the study. Since it prevents wearers from opening their mouths, the device restricted the participants in brushing their tongues and the lingual and palatal aspects of their teeth regularly, raising the question of whether this solution negatively affects dental hygiene. At the review appointment on the seventh day, participants had the opportunity to clean their teeth while the magnets were disengaged. None of them reported bad breath or gingival soreness. Few participants stated that they were unsatisfied with their oral hygiene during the treatment or after the device had been removed.

The researchers stated that, in contrast to their findings, several previous studies found that intermaxillary fixation resulted in patients developing halitosis and periodontal disease. However, it is arguable whether the two-week period in this study is sufficient to evaluate the impact on oral health. Dental Tribune International (DTI) contacted Brunton to enquire whether the device might have a negative impact on dental health if worn for a longer period and whether the force of the magnets could be harmful to the teeth or jaw. However, the University of Otago referred DTI to the study results and provided a general statement that had been published by the researchers.

Ethical concerns

After publication of the university’s press release, a heated discussion about the new device erupted on the university’s Twitter channel. The vast majority of commentators expressed negative sentiments about the innovation, calling it a “torture device” and “monstrous”. In addition, many Twitter users were surprised and appalled that the device had been approved by the ethics committee.

A fair share of comments accused the researchers of fat shaming, as well as of blaming and discriminating towards people with an eating disorder, based—among other points—on the study stating that one participant had admitted to “cheating” by consuming melted chocolate and fizzy drinks and the researchers’ response to this: “This was not surprising as studies have shown that obese patients usually have an addictive personality and an impulsivity for sugary food, and suffer from binge eating disorders.”

Concerns about the number of kilograms lost in 14 days, the risk of regaining weight quickly and worsened oral hygiene were also raised.

Among the many negative comments, however, were also some that defended the device. One user wrote: “I have been begging my gastric team to fit something like this for nearly two years. Something like the old braces with elastic bands. I fail to see how this is barbaric and chopping organs out of the body for weight loss isn’t.”

University of Otago releases additional statement

On 29 June, a day after the official press release, the university published a statement on DentalSlim Diet Control in which it emphasised that the device is a “safe and effective tool for weight loss”.

According to Brunton, its primary use is for patients who need to lose weight in preparation for a surgical procedure: “Many patients who are severely overweight find themselves being told they are not able to have surgery until they lose weight because it is not safe for them to be put under general anaesthetic; and that can be for any surgery such as hip replacement or kidney stone removal for example.”

He continued: “It’s important to note that this device is simply a tool available for those who want it. People will not be forced to use it—it’s a choice—and it’s a decision that a person would be able to make for themselves in consultation with medical professionals.”

“We acknowledge this won’t be for everyone, just like medication and surgery isn’t for everyone” – Prof. Paul Brunton, University of Otago

The statement stressed that, aside from the negative feedback, the researchers had received a considerable number of enquiries from people who would like to buy the device or participate in the next clinical study. In addition, other medical professionals have commended them for their innovation.

“We acknowledge this won’t be for everyone, just like medication and surgery isn’t for everyone, but for those who do want to go down this path, it is a safe option,” Brunton concluded.

Academy for Eating Disorders speaks up

In a press release on 13 July, the Academy for Eating Disorders, an international association committed to eating disorder research, education, treatment and prevention, said that the Medical Care Standards Committee of the academy was concerned about the rapid weight loss and subsequent weight gain, because these repeated weight cycles of weight loss and regain typically “result in worsened health outcomes and adverse cardio-metabolic risk”. The committee also criticised that the study did not include any psychological evaluation support, as this could raise the risk of creating or perpetuating eating disorder behaviours or other psychological issues.

The academy mentioned too that the study implied shame and stigma. In its opinion, the great potential for abuse, misuse and psychological damage of the device “is of grave ethical concern”. The statement closed with an appeal to the entire healthcare community to scrutinise the use of not only this device but of all weight loss methods that maintain weight stigma and may harm patients.

The study, titled “An intraoral device for weight loss: Initial clinical findings”, was published online on 25 June 2021 in the British Dental Journal, ahead of inclusion in an issue.

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