Locking ourselves into the past: the DentalSlim Diet Control device and an incomplete understanding of obesity

“Medieval torture device,” “molar muzzle,” “gastrointestinal gulag.” [1, 2]

These and other phrases have been used to describe the DentalSlim Diet Control, a weight-loss device first reported by Brunton et al. in a recent paper published in the British Dental Journal [3]. The device utilizes intraoral magnets to force patients onto a liquid diet and prevent them from opening their mouths beyond 2-mm wide. Although lauded as a “world-first” tool to fight the obesity epidemic, the device has significant limitations unaddressed in the original manuscript and may also have unintended effects in perpetuating weight stigma. As the DentalSlim device garners significant attention from the popular press and the lay public, it is imperative to address the device’s shortcomings and clarify standards of obesity treatment.

Brunton et al. report that mean weight loss of 6.32 kg was achieved over 2 weeks in a study cohort of six patients with well-tolerated side effects. According to the authors, most of the patients felt fairly pleased with the device and would participate in a future study. As such, the authors propose that their device may have general use for “many obese people,” but there are significant limitations to the study, some of which the authors acknowledge in their discussion [3]. For one, the 6 kg weight loss in 2 weeks is modestly impressive but somewhat irrelevant in terms of obesity management due to the short-time scale of the study; as an example, the International Journal of Obesity requires weight loss studies to have a duration of at least 12 months to adequately assess an intervention’s efficacy for obesity management [4]. Furthermore, given that only six patients completed the study, conclusions about the device’s potential for weight reduction or paucity of side effects should be made with caution. Indeed, the authors’ optimistic description of such side effects in text may ignore the multiple complaints patients had with the device, such as speech problems, difficulty relaxing, and total inability to function, as well as the findings that pain and unsatisfactory oral hygiene were present 2 weeks after device removal. Given no follow-up beyond those 2 weeks, there may also be other long-term deleterious implications to the device. While a carefully selected subset of patients with obesity, who cannot comply with dietary advice, may benefit from this device for short-term weight loss, to suggest the DentalSlim device as a general intervention and an “alternative to surgical procedures such as bariatric surgery” is unreasonable given the manuscript’s significant limitations [3].

Brunton et al. also portray obesity somewhat one-dimensionally with their remarks that the “main barrier to successful weight loss with dietary advice and restriction is poor patient adherence” and that their device could help “break addictive eating habits.” [1] Data on the very-low calorie diet (VLCD, <800 kcal per day) have shown that weight loss of 15 kg in 10–12 weeks is regularly achieved [5]; patients can successfully adhere to professional advice and lose weight without a device that locks their jaw to 2-mm wide. Certainly, patient adherence is critical and relevant to weight loss, but this compliance narrative without consideration of the multifactorial causes of obesity reflects an incomplete pathophysiological understanding of this disease. Given that the authors propose their device as an alternative to bariatric surgery and not as a tool solely for a carefully selected population, they should also acknowledge that obesity is a chronic disease predicated on genetic, environmental, developmental, and behavioral factors—heritability is estimated to be 70–80% for instance [6]. Depicting obesity as solely a problem of adherence reflects an outmoded understanding of obesity, and, indeed, many of the manuscript’s references about obesity, its complications, and treatment are 10–25 years old. The device and the present manuscript do not reflect a nuanced and holistic analysis of obesity.

The DentalSlim device may also be cause for concern given the infamous history of jaw wiring to combat obesity. Popularized in the 1980s, jaw wiring was similarly utilized for caloric restriction, but it induced significant side effects, including aspiration, periodontal disease, and soft tissue trauma. In addition to these physical side effects, jaw wiring frequently led to embarrassment and stigmatization among patients, which ultimately contributed to anxiety and other psychiatric conditions [7]. While the DentalSlim device is presented as a safe, efficacious advancement from traditional jaw wiring, by locking patients’ jaw movements in a similarly restrictive fashion, this device may have the unintended impact of furthering weight stigma. In the manuscript’s introduction, the authors recognize that individuals with obesity may be particularly vulnerable to developing eating disorders due to psychological symptoms of depression and loss of self-esteem caused by stigmatization and discrimination, yet these considerations are not comprehensively applied to the device itself. Study participants “indicated they occasionally felt embarrassed, self-conscious and that life, in general, was less satisfying,” so considerations of weight stigma are imperative for the DentalSlim device [1]. Given that weight stigma has been shown to decrease the likelihood that persons with obesity exercise, seek out care, and adhere to treatment and to increase the likelihood of weight gain [8], the DentalSlim device’s potential to contribute to bias and further damage how individuals with obesity are viewed by the general public should be thoroughly considered and examined.

Innovative interventions designed to address the global obesity epidemic should be encouraged. However, the DentalSlim device and the present manuscript face significant limitations as it relates to the study design, a lack of consideration of the complex pathophysiology of obesity, and a potential for weight stigma given the history of jaw wiring. Patient adherence is certainly a critical concern for physicians to contend with, but the DentalSlim device is not the answer at this time.