Acid reflux and tooth sensitivity: what stomach acid does to enamel.

If your teeth have started to twinge and you also get heartburn, wake with a sour taste, have just been started on a reflux medicine, or have been told by a dentist that the inside of your upper front teeth looks worn, stomach acid can be part of the reason: it softens and wears enamel on surfaces that food and drink rarely reach, and the dentine left exposed underneath reacts to cold. What to use is treatment for the reflux itself, from a pharmacist and then a GP, plus a fluoride toothpaste, a sensitivity toothpaste for the twinge, and a toothbrush kept away from your teeth straight after an episode; the wear will have been building for months, and what is sudden is noticing it. S3 Sensitivity Science™ contains 1450 ppm fluoride as sodium monofluorophosphate, which matters here because fluoride toothpastes reduced erosive tissue loss against fluoride-free controls in the pooled laboratory and in situ evidence¹². Fluoride helps enamel recover between acid attacks; no toothpaste, this one included, protects enamel from the stomach's acid itself.

What was checked24 peer-reviewed studies, guidance from the NHS and the Oral Health Foundation, and product information as published by S3

Can acid reflux make teeth suddenly sensitive, and what should you use?

It can make them sensitive, but the change underneath is rarely sudden. Erosion is mineral dissolved from the tooth surface a little at a time, and sensitivity arrives when enough has gone for dentine, the layer beneath the enamel, to be exposed; its microscopic channels run towards the nerve, and cold moves the fluid inside them. The Oral Health Foundation lists stomach acid among the acids that wear teeth into sensitivity¹¹. The acid does not attack the nerve. It removes the covering that kept the nerve's channels closed, and what feels like a sudden change is usually the week a cold drink finds the spot.

What to use comes in an order, and the toothpaste is not at the top of it.

1. The reflux. The NHS tells anyone who keeps getting heartburn to speak to a pharmacist, and to see a GP when heartburn happens most days or when pharmacy medicines and lifestyle changes are not helping¹². A 2012 review of reflux and tooth erosion puts it more bluntly for dentists: when the acid is coming from inside, medical referral and management of the reflux is the primary way to prevent further erosion¹³.
2. The toothbrush after an episode. Do not scrub a surface that has just been bathed in acid. In an in situ study, five volunteers wore human enamel samples in mouth appliances; brushing with a fluoride-free paste straight after an acid attack took 79.3 micrometres against 45.2 with acid alone, waiting two hours changed nothing (81.7), and brushing with a fluoride toothpaste brought the loss back to 51.5¹⁴. A systematic review and meta-analysis of twelve laboratory and in situ studies found no significant difference for human enamel between waiting and brushing at once, and a significant benefit from fluoride toothpaste². The argument over how long to wait belongs to the page on acidic food and drink triggers; for reflux, the useful habit is to rinse, let the mouth settle, and brush later with fluoride.
3. A fluoride toothpaste, every morning and night, for the surface.
4. A sensitivity toothpaste for the twinge. A 2026 network meta-analysis of 93 randomised trials rated stannous fluoride and arginine toothpastes as first-line options, found a large effect for nano-hydroxyapatite in two studies, and found a small effect with low confidence for potassium toothpastes¹⁵.
5. A dentist who knows about the reflux, because the wear is theirs to measure and the reflux may be news to your GP.

What does stomach acid do to enamel that food acid does not?

It arrives stronger, stays longer, lands in different places and turns up when saliva has gone quiet. A British Dental Journal review for dentists, written with a consultant gastroenterologist, gives the pH of gastric juice as between 1 and 3, and names hydrochloric acid and the digestive enzyme pepsin among its contents⁴. The 2012 review puts refluxed acid at about pH 1.2, and enamel starts to lose mineral below about pH 5.5¹³. A glass of orange juice is acidic; the contents of a stomach are acid on a different scale.

Timing makes it worse. Reflux during sleep comes in episodes that typically last 15 to 20 minutes, against one or two minutes while awake, and it happens when saliva production is much reduced; gastric acid pushes saliva off the tooth surface easily, and pepsin can strip away the thin protein film, the pellicle, that normally sits between the enamel and whatever arrives next¹³. In a London case-control study of 31 patients with throat and other reflux symptoms that reach beyond the oesophagus, acid was recorded just above the upper oesophageal sphincter more often than in seven controls, and the patients' palatal tooth wear correlated with acid reflux at night¹⁶.

An evening can be enough to show it. When 12 healthy volunteers ate a curry with alcohol two hours before sleep, all of them refluxed, six to a level gastroenterologists call pathological, and a pH sensor held against the palate recorded significantly more time below pH 5.5 than after a bland meal¹⁷. That was pH, not wear, in people with no reflux disease; it shows the route, not the damage. The NHS advice that follows from the same physiology is plain: do not eat within three or four hours of going to bed, and raise the head of the bed by 10 to 20 cm rather than piling up pillows¹².

Saliva may also be less help than usual. In a London comparison of patients referred to an oesophageal testing unit with controls, people with reflux had more palatal and more total tooth wear, their stimulated saliva buffered acid less well, and those who complained of hoarseness produced less of it¹⁸. A US study found no saliva abnormalities in its small dental group, so this is a finding in one population, not a rule¹⁹. Why dietary acid behaves the way it does, including the difference between how acidic a drink is and how long it keeps the mouth acidic, is on the page about acidic food and drink linked above, and the Journal's explainer on tooth enamel erosion covers what erosion is.

How would a dentist know the acid is coming from your stomach?

From where the wear sits, what it looks like, and what does not fit a diet history, and the evidence says this pattern often turns up before any heartburn does. The British Dental Journal review lists the signs: wear on the palatal surfaces of the upper teeth and on the biting surfaces of the lower molars, flattened biting contours, cusp tips hollowed into cups, and fillings that stand proud of the tooth around them⁴. In a Brazilian cross-sectional study of 235 adults examined by a dentist before an endoscopy, the most eroded surfaces were the palatal or tongue side and the biting surfaces, 25 and 25, with the cheek side far behind at five; in patients under 50, erosion went with acid regurgitation rather than with heartburn (adjusted prevalence ratio 1.8)²⁰.

Several studies ran the question the other way round, starting from the teeth. At a US referral centre, ten of 12 patients whose erosion had no obvious cause had reflux on 24-hour oesophageal pH monitoring; among gastroenterology patients, erosion was found in seven of ten whose reflux climbed into the upper oesophagus and in one of ten without reflux¹⁹. At Guy's Hospital, 23 of 36 people with palatal erosion of unclear cause (64%) had pathological reflux, and the authors advised assessing such patients even when they report no reflux symptoms²¹. In Bern, 141 of 161 patients presenting to dentists with erosive tooth wear (88%) had increased acid exposure in the oesophagus, and 86% of those followed up reported no reflux symptoms during the 24-hour recording⁷.

The most direct test of the dentist-first route is recent. In a cross-sectional study of 80 dental patients, 28 with the more severe erosion were sent for gastroenterology assessment; 27 were diagnosed with reflux disease, nine of whom had denied any history of it, and of 20 who had an endoscopy six had changes in the oesophagus, one of them Barrett oesophagus⁵. The UK review draws the conclusion for practice: nearly a quarter of adults with extensive palatal erosion in the studies it cites had reflux disease with no systemic symptoms, so in silent reflux the erosion may be the only sign, and a dentist who suspects it should refer to the patient's GP⁴.

The association does not show up everywhere. A single-centre Italian case-control study of 200 people with reflux disease and 100 matched controls found dry mouth, a burning or acid sensation, bad breath and redness of the palate more often with reflux, and no significant association with dental erosion¹⁰. The figure to hold is the pooled one: across 28 observational studies, the odds of erosion with reflux were five times those without it (odds ratio 5.00), with high heterogeneity between studies (I² 79.8%) and a slightly larger estimate, 5.59, where reflux had been confirmed with instruments³.

Vomiting is the other way stomach acid reaches teeth. The Oral Health Foundation names regular vomiting among the causes of erosion²², and a 2024 systematic review pooled erosive wear at 65% in people with eating disorders against 54.1% in reflux disease²³. Being sick often, for whatever reason, is something to take to a GP, and no toothpaste aisle has an answer for it.

The table sets out what each clue points towards. None of its cells is a diagnosis you can make in a mirror: the wear is examined by a dentist, reflux is confirmed by a doctor, and several of the clues overlap.

Does reflux cause sensitivity, or only erosion?

Reflux is firmly associated with erosion, and much less firmly with sensitivity, and nobody has measured the step a reader most wants to know about. The chain has four links, and they are not equally strong.

Reflux and erosion: strong. That is the pooled result in the section above³. Observational designs cannot prove the acid did it, but the pattern of surfaces, the pH recordings from the mouth and the referral work all point the same way⁴¹⁷⁵.

Erosion and sensitivity: an association. In a cross-sectional clinical study of 3,551 adults in seven European countries, financially supported by a maker of sensitivity toothpaste, dentine hypersensitivity was associated with erosive tooth wear and with heartburn⁹. Worn enamel and a twinge are recorded together; the design cannot say which came first or how often wear stays painless.

Reflux and sensitivity: an association, and a contradiction. In a 2013 European study of 3,187 adults aged 18 to 35 recruited in general dental practices, sensitivity was associated on the questionnaire with heartburn or acid reflux, and with vomiting⁸. The Italian case-control study pointed the other way: dental sensitivity was one of its main outcomes, and it was not among the findings more common in the 200 reflux patients¹⁰. The 2012 review that describes that study gives tooth sensitivity in 32.5% of the reflux patients and 32% of the matched controls¹³. Both results are printed here because both exist.

Treating reflux and less sensitivity: never tested. A PubMed search run for this page in September 2026, pairing reflux, regurgitation or vomiting with dentine hypersensitivity, tooth sensitivity or sensitive teeth, returned twenty-five records, made up of prevalence surveys, case reports, papers on eating disorders and reviews, and none of them followed people whose reflux was treated to see whether their teeth hurt less. Restricting the same pairing to trials returned none. A second search for toothpaste or remineralising trials in people with reflux returned five records, of which one was a trial, described below²⁴.

So the honest version is this. If you have reflux and sensitive teeth, the acid is a plausible reason for the wear, and the wear is a plausible reason for the twinge. That treating the reflux will make the twinge go away is a reasonable hope with no study behind it, which is why the sensitivity toothpaste stays in the routine while the reflux is dealt with.

What protects teeth when the acid comes from the stomach?

Treating the reflux comes first, and the case for it rests on firmer ground than anything squeezed onto a brush, though on less than its reputation suggests.

Two studies have followed teeth while reflux was treated. In a double-blind randomised trial of 30 adults with advanced erosion and reflux, funded by AstraZeneca, the maker of the drug it tested, three weeks of the proton pump inhibitor esomeprazole was followed by about half the enamel loss seen with placebo at the most exposed site, 7.2 against 15.25 micrometres, measured with an optical imaging device⁶. In Bern, 72 adults with erosive tooth wear and reflux were prescribed the same drug for a year: the wear did not progress further in 53 of them (74%) and progressed in 19⁷. That second study had no untreated group, so its authors could not separate the medicine from the natural ups and downs of reflux, and the lead author declares research funding from the same manufacturer for unrelated studies until 2008⁷. Sensitivity was not measured in either. Put together: a short controlled trial funded by the drug's maker, and a year of follow-up with nothing to compare against, both pointing the same way⁶⁷.

The medicines themselves are a pharmacist's and a GP's business. The NHS describes antacids and alginates from a pharmacy for short-term relief, proton pump inhibitors from a GP usually for four or eight weeks, and a return to the GP if symptoms come back when the medicine stops¹². The British Dental Journal review adds one dental detail: alginates are often taken last thing at night, and not all of them are sugar-free⁴.

After an episode. Rinse with water and leave the brush for later. Rinsing is common-sense advice that none of the studies on this page measured; not brushing a freshly softened surface with a fluoride-free paste is what the in situ evidence supports, and fluoride in the paste is what reduced the loss¹⁴². The Oral Health Foundation's own list for erosion adds finishing meals with milk or cheese and chewing sugar-free gum to bring saliva back²².

Fluoride. Across eight systematic reviews, fluoride toothpastes generally reduced enamel and dentine loss against fluoride-free controls, mostly in laboratory and in situ models, according to a 2026 umbrella review¹. The limit is stomach acid itself: the 2012 review reports that fluoride and casein-based remineralising agents gave some laboratory protection at pH 3.0 and none at pH 1.2¹³. Fluoride helps the surface recover between attacks; it does not make enamel resistant to gastric acid.

Stannous fluoride. On erosion, this is the paste active with the best evidence, and it is worth saying clearly on a page published by a brand whose formula does not contain it¹. The 2026 umbrella review found stannous-containing formulations the most consistently protective against erosive and erosive-abrasive loss, with moderate certainty, while rating the calcium-based and biomimetic technologies low or very low¹. A 2020 systematic review by university researchers found stannous fluoride more protective against erosion in seven of eight studies, most of them at high risk of bias²⁵. A 2021 meta-analysis drawn from one stannous toothpaste manufacturer's own archive, with the manufacturer's employees among its authors, reported an 83% benefit against enamel erosion over control pastes in six in situ trials²⁶. None of this was done in people with reflux, and the 2012 review describes the protection from metal-ion fluorides such as stannous fluoride as a laboratory finding, probably a physical barrier formed on the surface¹³.

Hydroxyapatite. S3 contains hydroxyapatite alongside its potassium nitrate and fluoride, so this paragraph costs something. In an independent laboratory erosion and abrasion model, none of the hydroxyapatite toothpastes tested reduced enamel loss against a control paste and two increased it, while a stannous fluoride toothpaste and a fluoride and stannous mouthrinse reduced it²⁷. That is enamel in a laboratory, not a person. The one randomised trial of a hydroxyapatite toothpaste in people with reflux followed 30 adults with erosion for a year, all of them on a zinc-hydroxyapatite toothpaste whose published ingredients contain no fluoride salt, half of them also using a hydroxyapatite paste in a tray; there was no significant change in the erosion score or in the air-blast sensitivity score in either arm, and no difference between them²⁴. Its abstract speaks of an improvement in dentine sensitivity, and the mean scores came down, yet no change inside either arm reached statistical significance in the published results, and with every participant on hydroxyapatite the trial cannot say whether the toothpaste did anything at all²⁴.

For the twinge. A sensitivity active is still worth using while the reflux is treated, because it works on the symptom rather than the cause: stannous fluoride, arginine and nano-hydroxyapatite toothpastes showed the larger effects at two weeks in the 2026 network meta-analysis, and potassium a small one with low confidence¹⁵. That review also notes that most of the trials it pooled were industry-funded¹⁵.

The table puts the measures side by side, with the strength of what stands behind each.

Where does S3 sit if reflux is part of the picture?

Below the reflux treatment, beside the fluoride, and on the symptom. The potassium is there for the nerve, the nano-hydroxyapatite for the inside of the tubule and the biomimetic hydroxyapatite for the surface, three jobs that do not overlap. Its 1450 ppm of fluoride comes as sodium monofluorophosphate, used because that salt does not react with the calcium of the hydroxyapatite sharing the tube. The trial in reflux patients described above used a hydroxyapatite toothpaste with no fluoride salt in its ingredients; S3 keeps fluoride in, so choosing it does not mean giving up decay protection.

Two things on this page cut against it, and they stay where they are. The paste active with the most consistent protective evidence against erosion in the 2026 umbrella review is stannous fluoride, and the formula behind this site does not contain it¹. In the independent laboratory model of marketed hydroxyapatite toothpastes, none reduced enamel loss and two increased it, and hydroxyapatite is in this formula²⁷. No trial of this formula has recruited people with reflux.

What that leaves is a daily toothpaste for the twinge and for the surface between attacks, used alongside treatment for the stomach, never instead of it. Unlike a single-active sensitivity paste, S3 is meant as the everyday toothpaste rather than a fortnight's course. Relief from its actives builds with use, as potassium gathers around the nerve and mineral is laid down brush by brush, which is why S3 is judged at two to four weeks. Nothing in the tube treats reflux, neutralises stomach acid or restores enamel that has gone, and this page does not suggest otherwise.

When should reflux and sensitivity send you to a GP or a dentist?

Heartburn most days, pharmacy remedies that are not working, trouble swallowing, being sick often or losing weight without trying are for a GP; worn teeth, pain that singles out one tooth, or a twinge that lingers are for a dentist. The NHS page sets the GP thresholds: lifestyle changes and pharmacy medicines not helping, heartburn on most days, or other symptoms such as food getting stuck in the throat, frequent vomiting or unexplained weight loss, with a call to a GP or to 111 if things are getting worse at any point¹². It also says not to stop a prescribed medicine without speaking to a doctor first¹². The British Dental Journal review asks dentists to treat difficulty or pain on swallowing, weight loss and bleeding as red flags⁴.

Silent reflux is still worth the appointment. In the referral study above, changes in the oesophagus turned up at endoscopy in people who had never been diagnosed, including some who denied any reflux history⁵. The NHS heartburn page is written about the oesophagus and does not discuss teeth; a dentist sees the other end of the same problem, so tell your GP what the dentist found and tell your dentist about the heartburn.

For the teeth, the Oral Health Foundation's reasons to book a dental appointment rather than try another tube are pain that is severe, sensitivity that has gone on for more than a few weeks, a single tooth affected, or pain that started out of nowhere¹¹. The NHS gives toothache two days: after that, or sooner if painkillers are not touching it, if you have a temperature, pain on biting, red gums or a bad taste, see a dentist rather than a GP, and go to A&E if swelling reaches the eye or neck or makes it hard to breathe, swallow or speak²⁸. A tooth that aches on its own, or keeps aching after the cold has gone, is not what a sensitivity toothpaste is for.

Frequently asked questions

Can S3 repair enamel that stomach acid has worn away?

Enamel that has worn away does not grow back, whichever toothpaste is used, because the cells that formed it are gone once a tooth has come through the gum. Mineral can be laid back onto a softened surface, which is a different thing from replacing a surface that has been lost; the page on nano-hydroxyapatite and remineralisation sets out the difference. Against erosion, the hydroxyapatite toothpastes tested in one laboratory model did not reduce enamel loss, and two increased it²⁷. What S3 offers someone with reflux is fluoride at full adult strength and actives aimed at the twinge; the protection that counts for the enamel is treatment of the reflux, which a review of the subject calls the primary way to prevent further erosion¹³.

Should I brush my teeth after reflux or being sick?

Not straight away. Rinse with water, let the mouth settle, and brush later with a fluoride toothpaste. In the in situ study, brushing with a fluoride-free paste just after an acid attack nearly doubled the enamel lost, waiting two hours did not help, and fluoride in the paste reduced the loss¹⁴. The Oral Health Foundation advises waiting at least an hour after acid before brushing²². If being sick is happening often, the appointment to make is with a GP.

Can I have reflux without heartburn?

Yes, and it is common among people whose teeth show the wear. In the Bern follow-up, 86% of the patients tracked reported no reflux symptoms during a 24-hour recording that found acid in the oesophagus⁷. In the dental referral study, nine of those diagnosed with reflux after referral had denied any history of it⁵. The NHS lists a hoarse voice, a cough or hiccups that keep coming back, and bad breath among the other symptoms, so heartburn is not the only clue¹².

Is a stannous fluoride toothpaste better for reflux?

For erosion, a 2026 umbrella review of systematic reviews found stannous formulations the most consistently protective of the paste actives, with moderate certainty and mostly from laboratory and in situ work¹. None of it was gathered in people with reflux, and it measures tissue loss, not sensitivity. For sensitivity on its own, stannous fluoride was among the first-line options in the 2026 network meta-analysis of randomised trials¹⁵. It does not replace treatment of the reflux, and a dentist who has seen the wear can say which paste suits it.