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Eating disorders and Orthodontics FMC

Eating disorders are serious complex mental illnesses that affect people of all ages, genders, ethnicities and backgrounds, and there are currently estimated to be around 1.25 million sufferers in the UK. Such conditions are relatively common amongst the Western European and North American populations and are associated with the highest morbidity and mortality rates of any mental disorder among adolescents.

As peak prevalence of eating disorders occurs during adolescence, it commonly coincides with referral for orthodontic treatment, so we should bare this in mind when assessing patients’ suitability for braces.

Eating disorders are defined as forms of psychological illness, characterised by significant disturbances in a person’s eating behaviour, often resulting in extreme over- or under- eating with a fixed body image and weight ideal.

Anorexia Nervosa:

  • Peak incidence thought to be 15 and 16 years of age for young women and men.
  • Unexplained seriously low body weight (BMI < 85% expected weight)
  • Intense fear of gaining weight
  • Restricted energy intake
  • Behaviours to counteract weight gain such as self-induced vomiting, excessive exercise and laxative misuse (purging)

Bulimia Nervosa:

  • Frequently diagnosed between 15-19 years of age
  • Weight considered normal
  • Recurrent binge eating (eating, within 2 hours, an amount of food larger than most people in similar circumstances)
  • Recurrent purgative behaviour to prevent weight gain (vomiting, laxatives, diuretics, fasting or excessive exercise)


  • Refers to diabetic patients suffering with bulimia
  • Affects type I Insulin-dependent diabetics
  • Individuals restrict/limit their insulin dose to lose or control body weight

Binge-eating disorder (BED):

  • Median age of onset is considered to be late teens to early twenties
  • Recurrent and frequent episodes of binge eating
  • Three or more of the following: eating rapidly until uncomfortably full, eating large amounts of food although not hungry, eating alone due to embarrassment of quantity, feeling disgusted, depressed or very guilty afterwards
  • Does not involve compensatory behaviours so patients are often overweight


  • Regularly consuming non-food substances that have no nutritional value, such as paper, soap, paint, chalk, or ice
  • Behaviour must be present for at least one month, not part of a cultural practice, and developmentally inappropriate
  • Iron-deficiency anaemia, pregnancy and malnutrition are common aetiological factors
  • Most common eating disorder in individuals with learning disabilities, affecting around 10–15% of these patients

Avoidant/restrictive food intake disorder (ARFID):

  • Characterised by avoidance of certain foods or types of food
  • Persistent failure to meet appropriate nutrition or energy needs
  • Avoid foods due to low interest in eating, concerns regarding eating particular foods (may have had previous bad experience) or sensory issues with certain foods
  • Significant loss of weight, nutritional deficiency, dependence on nutritional supplements, impaired psychosocial functioning

Rumination disorder:

  • Can affect anyone at any age
  • Involves repetitive, habitual bringing up of food that might be partly digested
  • Patients may re-chew and re-swallow food or just spit it out
  • People suffering often do not feel in control of their disorder
  • Can lead to malnutrition, weight loss, dental erosions, and electrolyte disturbances if left untreated

So, how do eating disorders manifest intra-orally?

Mucosal and soft tissue effects

Patients with eating disorders are frequently nutritionally deficient, making them prone to angular cheilitis, glossitis and recurrent aphthous ulcers. Additionally, there is a high prevalence of streptococci, lactobacilli and oral yeasts (candidosis), particularly in bulimic patients.

There may also be intra-oral signs of trauma from the use of fingers and objects, such as pens and hairbrush handles, used to induce vomiting.

Salivary manifestations

Frequent vomiting alters the natural balance of salivary flow and the oral microbiome, often causing salivary gland hypertrophy.

Reductions in salivary flow, dehydration and xerostomia, coupled with episodes of binge eating, make bulimic patients’ susceptible to caries. The same cannot be said for anorexic patients, who often avoid eating altogether.

Furthermore, patients with eating disorders may take antidepressant medication, a known side effect of which is xerostomia, further increasing their caries risk.

Dental complications

Tooth surface loss as a result of induced vomiting is commonly seen in patients with Bulimia Nervosa and Anorexia Nervosa.

Erosion due to purging is most likely to be observed on the lingual/palatal (incisors, canines and premolars) and occlusal surfaces (molars, premolars), its severity dictated by frequency of vomiting and subsequent oral hygiene habits. In contrast, erosion is more likely on the buccal surfaces of those who ingest citrus fruits in a bid to supress their appetite.

Erosion causes dentine exposure and sensitivity, as well as darkening of teeth. Should purging persist, pulpal exposure and reduced clinical crown height may result.

With increasing numbers of people seeking orthodontic treatment, we may encounter both patients with newly established eating disorders as well as those with a previous history who are seeking restoration of their dentition.

A multi-disciplinary approach, to align teeth, restore vertical dimensions and provide clearance for restorations, may be required to allow worn and broken teeth to be rebuilt. Liaising with our restorative colleagues will provide the best overall results.

When treating these patients there are several orthodontic considerations to be borne in mind:

  • Maintenance of optimal oral hygiene to reduce the risk of caries where salivary flow is reduced, as orthodontic appliances have been shown to be plaque retentive
  • Instructions to avoid brushing immediately after vomiting to reduce tooth surface loss
  • Slower tooth movement as a result of reduced bony turnover and healing due to malnutrition, particularly in in anorexic patients, can mean longer treatment duration
  • Some ceramic brackets have increased bond strength so it may be best to avoid those on teeth already worn and fragile.
  • As orthodontists who see their patients regularly, often during the teenage years, we are perfectly positioned to
  • As orthodontists who see their patients regularly, often during the teenage years, we are perfectly positioned to

Having recently treated several adult patients with dentitions ravaged by eating disorders, I can tell you that they keep their cards close to their chest and struggle to talk openly about their experiences.

As orthodontists who see their patients regularly, we are perfectly positioned to monitor such patients and build relationships, providing a safe and comfortable environment for them to share, should they feel the need to.

Whilst the subject of eating disorders may be difficult to broach, it is imperative that action is taken to ensure our patients receive timely referrals to appropriate healthcare teams in an effort to reduce morbidity and mortality, and help minimise the associated adverse dental effects.

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