Sensitive teeth and eating disorders: acid erosion, gentle care and getting help.

When teeth turn sensitive in someone who is being sick often, the usual cause is stomach acid, which softens and wears away the enamel that covers the dentine underneath, most often on the inner faces of the upper front teeth¹². What helps is short and free of judgement: rinse with water or a non-acidic mouthwash after vomiting, do not brush straight away, keep brushing twice a day with a fluoride toothpaste, see a dentist regularly, and talk to a GP about the eating disorder itself, which is where the most useful help starts³⁴⁵. S3 Sensitivity Science™, the toothpaste made by the publisher of this page, contains full adult-strength fluoride at 1450 ppm.

What was checked17 peer-reviewed studies, product information as published by S3, and guidance from NICE, the NHS and the Oral Health Foundation

If you are struggling with eating, you do not need a plan for your teeth before asking for help. The NHS says to see a GP as soon as you can if you think you may have an eating disorder, and it gives the number of the Beat helpline, 0808 801 0677, where you can talk to an adviser in confidence⁵. If you need urgent help for your mental health, the NHS says to call 111 and choose the mental health option, and to call 999 or go to A&E in an emergency¹⁰.

Why can vomiting make teeth sensitive?

Because stomach acid softens and strips enamel, and enamel is the layer that keeps the more sensitive dentine covered. The Oral Health Foundation names regular vomiting among the causes of dental erosion, explains that enamel softens and loses minerals during each acid attack, and warns that brushing while it is soft can remove tiny amounts of it¹. The NHS page on bulimia puts the risk in one line: stomach acid can damage tooth enamel if you are being sick a lot⁴.

The wear has a recognisable pattern. A 2021 review in the journal Periodontology 2000 places the erosion linked to vomiting mainly on the palatal surfaces of the incisors, the inner faces of the upper front teeth². Reflux brings stomach acid into the mouth too, and a meta-analysis of 28 observational studies found dental erosion in about half of adults with reflux disease and about a fifth of people without it¹¹; the page on acid reflux and tooth sensitivity covers that route, and the page on acidic food and drink triggers covers acid from the diet. The Journal's article on tooth enamel erosion explains the process itself.

How strong the link is has been measured for erosion more carefully than for sensitivity. A 2015 systematic review and meta-analysis pooled ten studies with 556 patients and 556 controls: people with an eating disorder had five times the odds of dental erosion (95% CI 3.31 to 7.58), 7.32 times with self-induced vomiting, more decayed, missing and filled tooth surfaces, and about twice the odds of reduced salivary flow⁶. A 2024 systematic review and meta-analysis of 33 studies, which added dentine hypersensitivity to the outcomes it examined, found erosion, decay, gum inflammation and dentine sensitivity all more common in people with an eating disorder, and lower salivary flow and pH, while calling every estimate uncertain because the certainty of evidence was very low⁷. Both reviews compared groups of people at one point in time. They describe how often erosion goes with an eating disorder; they cannot say what will happen to any one person's teeth.

The sensitivity evidence comes from a handful of small studies. In a Helsinki case-control study of 35 people with bulimia and 105 matched controls, the people with bulimia had more severe erosion, more often had a dry-feeling mouth, and had teeth more sensitive to cold and to touch¹². In a case-control study of 33 women outpatients with anorexia or bulimia nervosa and matched controls, self-reported dentine hypersensitivity was more common in the outpatients and was highly correlated with vomiting¹³. One clinical study tested teeth rather than asking: among 30 people with bulimia treated at a university dental clinic in Bulgaria, 29 had at least one sensitive tooth, 47.15% of the teeth with erosion were sensitive, and cold and toothbrushing were the triggers people named most often¹⁴. It had no comparison group, so its figures describe one clinic's patients rather than a difference from people without bulimia¹⁴.

A PubMed search run for this page on the tenth of September 2026, pairing eating disorders, bulimia, anorexia or self-induced vomiting with dentine hypersensitivity or tooth sensitivity, returned twelve records, and adding toothpaste or dentifrice to the same search returned none. Sensitivity in people with an eating disorder has been counted and described. No toothpaste, and no other treatment for the sensitivity, has been tested in them.

What should you do after vomiting to protect your teeth?

Rinse, hold off brushing, and keep fluoride on the teeth every day. NICE, the body that writes clinical guidelines for the health service in England, asks professionals to encourage people with an eating disorder who are vomiting to have regular dental and medical reviews, to avoid brushing their teeth immediately after vomiting, to rinse with a non-acid mouthwash, and to avoid highly acidic food and drink³. The NHS page on bulimia says the same in plainer words: rinse your mouth with water or a non-acidic mouthwash after vomiting to protect your teeth, and see your dentist regularly⁴.

How long to wait is where the advice stops agreeing. NICE and the NHS say not to brush straight away and give no time at all³⁴. The Oral Health Foundation's page on pregnancy, written with morning sickness in mind, says to rinse with water or a fluoride mouthwash after vomiting and to wait at least 30 minutes before brushing⁸. Its page on dental erosion says to wait at least one hour after eating or drinking¹. The 2021 periodontal review's own checklist for people with eating disorders says at least one hour after vomiting².

None of those times was measured in people who vomit. The best summary of the waiting question is a 2020 systematic review and meta-analysis of twelve laboratory and in situ studies, which found no significant difference in the wear of human enamel between brushing straight after an acid attack and waiting, while brushing with a fluoride toothpaste did reduce that wear¹⁵. The acid-triggers page linked above goes through the individual studies behind that review, one by one. For this page, the sensible reading is to leave softened enamel alone for a while after being sick, and to treat the exact number of minutes as a rule of thumb that has never been tested in people.

Rinsing has slightly more behind it, though still not in people who vomit. In an in situ crossover study, volunteers wore palatal appliances holding slabs of enamel that had been exposed outside the mouth to hydrochloric acid, as a stand-in for stomach acid; rinsing afterwards with a sodium bicarbonate solution left less enamel surface loss than rinsing with water, and neither rinse made the softened enamel harder¹⁶. A second PubMed search, for rinses or mouthwashes after vomiting in trials, returned five records on the same day, and none tested a rinse in people who were being sick. Bicarbonate rinses are not part of the NICE or NHS advice, so ask the dental team before making one.

The table puts the steps side by side, with the kind of evidence behind each.

What about brushing, dry mouth and medicines?

Brush gently, and treat a dry mouth as a separate problem with its own help. The 2021 review that describes where vomiting erosion sits also reports that brushing three or more times a day has repeatedly been found in people with eating disorders, that the brushing is often intense, and that emerging evidence links such brushing with receding gums². Receding gums uncover root surfaces, which is a separate way for teeth to become sensitive, and the review is open that no study has yet measured how much brushing damage leads to recession². The NHS suggests a soft toothbrush while a tooth is sore¹⁸, and the review's checklist suggests brushing no more than three times a day².

A dry mouth is common with an eating disorder, and why it happens is disputed. The 2015 meta-analysis found about twice the odds of reduced salivary flow⁶, and the Helsinki case-control study found low salivary flow and a dry-feeling mouth more often in people with bulimia¹². A 2017 literature review by two authors at King's College London Dental Institute states that reduced saliva is common in bulimia but is often down to antidepressant medicines rather than diet or vomiting, and mostly affects saliva at rest²⁰.

A matched case-control study points the other way. In that case-control study of 54 people starting outpatient treatment for an eating disorder and 54 controls, a very low resting saliva flow was almost twice as common in the eating-disorder group, 39% against 21%, yet the two groups took medicines known to dry the mouth equally often, and those medicines did not track saliva flow within the eating-disorder group²¹. Its authors conclude that low saliva in eating disorders is not a matter of medication alone²¹. The paper's own abstract words the saliva result the other way round, and this page follows the results section of the full text, which reports it as above²¹. The review and the study disagree, and this page does not choose between them.

Whatever the cause, the NHS advice on a dry mouth is practical. It suggests sugar-free gum or sugar-free sweets, brushing twice a day and an alcohol-free mouthwash because decay is more likely when the mouth is dry, and avoiding acidic, spicy, salty or sugary food; people who still have their own teeth are told not to use acidic artificial saliva products¹⁷. It lists medicines among the causes, says to see a GP if a prescribed medicine might be behind it, says a pharmacist may suggest things in the meantime, and says not to stop taking a prescribed medicine without medical advice first, even if you think it is the cause¹⁷. The page on a daily routine for dry mouth and enamel goes further into saliva substitutes and gum.

Does the toothpaste matter, and where does S3 fit?

Less than the steps above, and the part that matters most is the fluoride. No toothpaste has been tested for sensitivity in people with an eating disorder, and that includes S3, the toothpaste this page's publisher makes, which keeps full adult-strength fluoride at 1450 ppm. Everything known about sensitivity toothpastes comes from trials in people in general, so the choice is made the way anyone else would make it, by the active ingredient and the fluoride. The Journal's article on why teeth suddenly become sensitive covers the other common causes.

Fluoride has the clearest case after acid. In the 2020 meta-analysis on delayed brushing, the one positive finding was that brushing with a fluoride toothpaste reduced the wear of human enamel after erosion and abrasion¹⁵. The periodontal review advises people at risk of erosion to add a fluoride source, a toothpaste or rinse with fluoride combined with stannous ions².

If protecting enamel from acid is your main aim, the most consistent support is for stannous-based toothpastes: a 2026 umbrella review of eight systematic reviews rated that evidence moderate in certainty, and rated it low or very low for calcium-based and biomimetic toothpastes, hydroxyapatite among them, with most of the underlying work done in laboratory and in situ models²². The umbrella review's authors add that those experiments should not be read as proof that any toothpaste slows erosion in people²². S3's fluoride is sodium monofluorophosphate, not stannous fluoride, and this page does not offer S3's hydroxyapatite as protection against acid from vomiting. So if enamel wear worries you more than sensitivity does, a stannous fluoride toothpaste has the better-supported case on that umbrella review, and S3 is not one²².

For sensitivity in people generally, a 2026 network meta-analysis pooling 93 randomised trials gave its only high-confidence two-week rating to stannous fluoride on the cold-air test, and rated the small benefit of potassium toothpastes with low confidence²³. An older network meta-analysis estimated a large effect for potassium combined with hydroxyapatite, from just two trials and 140 patients²⁴. S3 is built around that pairing for sensitivity, with hydroxyapatite to occlude open dentine tubules and potassium to desensitise the nerve, each doing a job the other cannot. None of that has been tested against acid from vomiting, and none of it stands in for the rinse, the wait or the dentist.

One finding is worth knowing early. The authors of the Helsinki case-control study wrote that tooth tissue lost to erosion remains lost even if the eating disorder goes, and called for more to be done to protect teeth¹². That is a reason to start protecting teeth now, not a reason to think nothing can be done, since a dentist can restore worn teeth, as the next section describes. This page does not suggest that a toothpaste rebuilds tissue that has already been lost.

What will a dentist do, and will they judge you?

A dentist's job is to look after the teeth, the dental team can also help with the next step towards support, and the fear of being judged has been studied in its own right. NICE lists atypical dental wear, such as erosion, among the physical signs that can point to an eating disorder³. A 2023 review article for dental teams in the British Dental Journal, written by two NHS eating-disorder psychiatrists, says a general dental practitioner may be the first health professional to realise that someone is struggling, and describes the team's part as exploring that sensitively, pointing the person to their GP or a local eating-disorder support network, and treating the effects on the teeth⁹. The same review article states that anyone of any background, gender or ethnicity can develop an eating disorder⁹.

The worry about judgement is real and documented. In a qualitative study of 12 people in Australia with lived experience of an eating disorder, embarrassment, shame and the cost of treatment kept people from the dentist at times, and some stayed away for fear of being judged or of their parents finding out²⁵. Many of the same people described good experiences with their dentist once they went, and most said the professionals treating their eating disorder had given them little or no information about their teeth, which they wanted²⁵. The participants lived in Australia, where dental care is paid for differently, so their accounts travel as experiences rather than as figures.

You can decide how much to say. Telling the dentist that you are being sick often, or were in the past, gives them the context for what they see, and if you are worried about who else might find out, you can ask them that before you say anything else. Where the wear is advanced, teeth can be restored: the 2021 review describes rebuilding them with composite, veneers, onlays or crowns, and notes that cost has to be part of that decision².

In England, the NHS page on free dental treatment lists people under 18, or under 19 and in full-time education, people who are pregnant or have had a baby in the last 12 months, treatment from a hospital dentist and people receiving certain benefits, and says people on a low income may get help with part of the cost through the NHS Low Income Scheme²⁶. An eating disorder on its own is not one of the listed reasons. The page on free and low-cost NHS dental options sets out the charges and the other routes. A toothache that lasts more than two days is a reason to see a dentist rather than a GP, according to the NHS¹⁸.

How can you get help, or help someone else?

Start with a GP, and take someone with you if that would make it easier. The NHS page on eating disorders says the GP will ask about your eating habits and how you are feeling and will check your overall health, and that bringing a friend or loved one to the appointment may make it easier⁵. If being weighed is hard, the NHS page on bulimia says you can tell the GP you do not want to know how much you weigh⁴. For bulimia, the same page says a GP can refer you to an eating disorder specialist or another expert, and lists talking therapies among the treatments⁴.

If you would rather talk to someone before seeing a doctor, the helpline the NHS names is run by the eating disorder charity Beat, on 0808 801 0677⁵. The NHS page on urgent mental health help also lists Samaritans on 116 123 and, for anyone under 19, Childline on 0800 1111¹⁰.

If you are worried about a friend, a partner or your child, the NHS advice is to let them know you are worried about them, encourage them to see a GP and offer to go with them⁵. The NHS page on bulimia links to support for family, friends and carers, including a helpline for parents⁴. For some people a dental appointment is an easier first step, and the dental team can point towards the GP from there⁹.

Frequently asked questions

Is S3 suitable if I have an eating disorder?

S3 is a sensitivity toothpaste with full adult-strength fluoride, 1450 ppm, and it makes no claim for an eating disorder or for any other medical condition. Its formulation scientist puts it plainly: it is a cosmetic, not a medical device, and the company does not comment on using it for a medical condition. No toothpaste has been tested for sensitivity in people with an eating disorder, so the things to get right are the fluoride, gentle brushing and not brushing straight after being sick. A prescription fluoride paste, if you need one, is a dentist's decision.

How long should I wait to brush after being sick?

Nobody knows the exact time. NICE and the NHS say only not to brush straight away³⁴, the Oral Health Foundation's pregnancy page says at least 30 minutes⁸, and a specialist periodontal review says at least an hour². The laboratory and in situ studies pooled in a 2020 meta-analysis did not find that waiting made a significant difference to human enamel¹⁵. In the meantime, rinse with water or a non-acidic mouthwash.

Can the damage to my teeth be repaired?

The enamel itself does not come back: the researchers behind the Helsinki case-control study wrote that tooth tissue lost to erosion remains lost even when the eating disorder has ended¹². A dentist can restore worn teeth, and where wear is advanced a 2021 review describes composite, veneers, onlays or crowns, with the cost taken into account². Protecting what is left starts with the rinse, the wait and fluoride, and it is worth doing at any point.

Will my dentist be able to tell?

Possibly. NICE counts erosion and other unusual dental wear among the signs that can suggest an eating disorder³, and a review article for dental teams says the dentist may notice before any other health professional⁹. What that article asks of the dental team is to raise it gently, treat the teeth and point towards the GP or local support⁹. You can also tell them first.

I'm worried about a friend or my child: what should I say?

Say that you are worried about them, encourage them to see a GP, and offer to go along; that is the NHS advice⁵. The NHS page on bulimia also points families, friends and carers to support of their own, including a parents' helpline⁴.