Sensitivity toothpaste for a single tooth: why one-tooth pain usually needs a dentist.

One tooth that has suddenly become sensitive needs a dentist's look before it needs a sensitivity toothpaste, because the trials behind those toothpastes recruited teeth already diagnosed as sensitivity, and no symptom check has been shown to tell sensitivity apart from a crack, decay or an inflamed nerve¹²³. Keep brushing your whole mouth as normal with a fluoride toothpaste while you wait for the appointment, a sensitivity toothpaste included, but do not spend weeks testing a paste on that tooth first. S3 Sensitivity Science™, like every sensitivity toothpaste, is made as a complete daily toothpaste for twice-daily use across the whole mouth; it is not a test of what is wrong with one tooth.

What was checked18 peer-reviewed studies, guidance from the NHS and the Oral Health Foundation, and product information as published by S3 and by Sensodyne

Why is one sensitive tooth a different question from a mouthful of them?

Because sensitivity is diagnosed by ruling other things out, and for a single tooth that has just started to hurt, nobody has ruled anything out yet.

The ruling-out is written into the definition. A 2013 overview of the diagnostic criteria describes dentine hypersensitivity as always a diagnosis of exclusion, confirmed only once the other possible causes have been eliminated, and lists the conditions that can produce the same symptoms: a cracked tooth, a fractured or leaking filling, a chipped tooth, decay in the crown or the root, sensitivity after dental treatment, pulpitis, inflamed gums, tooth whitening and atypical tooth pain². The 1997 consensus guidelines for trials of desensitising products follow the same order¹. People are selected on a clinical diagnosis of the condition, those with conflicting characteristics such as active dental treatment are left out, several sites may be scored in one person, and the preferred places to test are the cheek-facing surfaces of incisors, canines and premolars¹.

Trials do not always manage that step. When a 2026 scoping review with a Delphi consensus went through 72 papers on how the condition is defined, few applied the whole of the accepted definition, and the part the review singled out as most often left incomplete was the exclusion of other causes of tooth pain¹¹.

How many teeth does ordinary sensitivity involve? Published counts disagree, and the disagreement is more useful than an average. In a 2002 clinical screening study of 117 people examined as possible recruits for a desensitising toothpaste trial in London, 1,561 of 3,136 eligible teeth responded to a probe, a cold-air blast or both¹². A population-based study of 2,120 adults in Shanghai, chosen by stratified random sampling and tested with cold air, reports 3.2 sensitive teeth per patient, with premolars making up 49.6% of them¹³. A population-based clinical study of 1,023 adults aged 35 and over in Porto Alegre, Brazil, examined at home, found that sensitivity affected about one tooth per affected person¹⁴. And in a cross-sectional clinical study at a Brazilian dental-school clinic, 51.7% of 118 patients had sensitivity, yet only 5.82% of the 2,902 teeth examined reacted to air¹⁵.

Each of those counted people differently, so no rule about one tooth falls out of them, and nothing here makes a single sensitive tooth proof that something else is wrong. The point is narrower. A sensitivity toothpaste comes with evidence gathered on people whose teeth were scored across the mouth after an examination, and a tooth that began hurting last week has had neither the scoring nor the examination. The page on one tooth that has suddenly become sensitive takes the usual culprits one at a time; this page stays with the toothpaste's side of the question.

What did the trials behind sensitivity toothpastes leave out?

Several of the things a single sore tooth might turn out to be, though not in every trial and never with the same list. The table copies the eligibility rules of four open-access trials, each read in full for this page, covering potassium nitrate, nano-hydroxyapatite, stannous fluoride, oxalate, aluminium lactate and calcium sodium phosphosilicate. Every one of them was run or funded by a toothpaste manufacturer, and the first column says which; that matters less than usual here, because the question is not what the trials found but which teeth they let in⁴⁵⁶¹⁶. The last two rows are the 1997 trial guidelines and the 2013 list of conditions a diagnosis of sensitivity is meant to rule out¹².

Read across the rows and three things stand out. All four trials enrolled teeth that an examiner had provoked with air or a probe, and three of them tied that to exposed dentine at the neck of the tooth, receded gum or wear⁴⁵⁶¹⁶; each of the four was funded by, or written with, the manufacturer of a paste it tested. Two of the four named decay and enamel cracks among the teeth they turned away; one excluded "teeth with pathology likely to cause pain" without saying what that covered; and one excluded recently filled teeth, teeth with gum or bite-related pain and bridge or denture supports, without naming decay or cracks. And two would not have taken a person with a single sensitive tooth at all: one needed two qualifying teeth, the other four at screening and two at the start, in trials funded by Procter & Gamble and by GSK⁴¹⁶.

The authors of the Procter & Gamble trial, seven of them employees of the company that makes one of the pastes they tested, set out the logic in their own introduction: dental professionals often attribute pain to dentine hypersensitivity "once other sources (e.g., dental caries, cracked-tooth syndrome, defective restorations) are excluded"⁴.

S3's actives sit inside this evidence, not outside it: potassium nitrate was one of the actives in two of these trials and nano-hydroxyapatite in one, and none of them tested S3. Whatever is known from them about potassium nitrate or hydroxyapatite was learned on teeth that had been looked at first.

Nobody appears to have published this as a table. A PubMed search for reviews and guidelines on exclusion criteria in this field, run for this page in September 2026, returned sixty-three records, and not one of them sets out which teeth were turned away. The page on how desensitising toothpastes are tested explains the air and probe scores in the table.

Can you tell from the pain whether it is "just sensitivity"?

No, and the research suggests that a dentist listening to a description cannot either; that is what the examination is for.

Start with the test that sounds most reliable, how the tooth reacts. When a 2012 systematic review asked how well toothache, or an abnormal reaction to heat or cold, reveals the condition of the nerve inside a tooth, not one of its 18 included studies reached high quality, and it called the evidence insufficient⁷. That does not make the signs worthless. It means nobody has shown how far they can be trusted.

Descriptions fare no better. The 2013 overview of diagnostic criteria notes that people describe their history, symptoms and discomfort so differently that the account alone does not allow a reliable and valid diagnosis, and that dentists often find it hard to tell dentine hypersensitivity from other painful conditions². A second 2013 overview, on diagnosis in the dental office, concluded from the limited published data that dentists are not routinely examining for sensitivity or ruling out other causes of dental pain before managing it, and may be relying on what patients tell them¹⁷. Even a validated questionnaire does not split the two: a pain questionnaire of 16 items, developed and validated in a clinical study in London for patients to fill in themselves, scores reversible pulpitis, a nerve that is inflamed but can still settle, in the same group as sensitive dentine³. Questionnaires for the nerve itself are getting better. In a 2025 clinical study validating an 11-item pulp-pain questionnaire, the questionnaire told reversible from irreversible pulpitis apart with high accuracy in 300 adults who had come to a clinic with symptoms of pulpitis, checked against a dentist's history, examination, X-rays and pulp tests¹⁸. It was built for people already in the dental chair, and its abstract says nothing about sensitive dentine, so it does not turn one sore tooth into something to judge at home.

The trigger is no guide either. Cold was the main complaint among the London trial recruits described above¹², and it is also what cracked teeth most often complain of: among 2,858 back teeth with a visible crack, enrolled by 209 dental practitioners in the United States in a practice-based study, 37% hurt with cold, against 16% that hurt on biting and 11% that hurt out of nowhere⁸. It started from teeth known to have a crack, so it gives no odds for a cold-sensitive tooth. What it removes is "it only hurts with cold" as a reason to relax.

The Oral Health Foundation's toothache page gives three possible causes for a sharp pain with cold: receding gums, a lost or worn filling, and a cracked or broken tooth¹⁹. Of the three, receding gums alone leave the kind of exposed dentine a sensitivity toothpaste was tested on.

What each of the others feels like, and what a dentist looks for, has its own page: a cracked tooth or a sensitive tooth, sensitivity or a cavity, sharp and brief or dull and lingering pain and pain that lingers after the trigger has gone. Hot and cold together is a pattern with a page of its own.

Can you keep using S3, or any sensitivity toothpaste, while you wait to see a dentist?

Yes. Brush your whole mouth as normal, morning and night, spit out, and keep the appointment where it is.

S3 is designed as a complete daily toothpaste that is safe for twice-daily use, and like every sensitivity toothpaste it cannot tell you what is wrong with one tooth. The trials behind its actives, funded by the manufacturers of the pastes they tested, were run on teeth an examiner had already picked out as sensitivity, with recently filled teeth, and in one of them decay and enamel cracks, ruled out first; none of them was run on a tooth nobody had looked at⁴⁵⁶.

The wait is the problem, not the paste. S3's own wording is that it is judged at two to four weeks. For a mouth of ordinary sensitivity that a dentist has already seen, that is a fair window. For one tooth that started hurting last week it is the wrong wait, because a paste's timetable is no reason to leave a possible crack or cavity unexamined.

Could a sensitivity toothpaste dull the twinge enough to hide what is behind it? Nobody has measured that, and the questions at the end of this page say what was searched. The risk this page can name is the delay.

For the sore tooth itself, the NHS suggestions while you wait for an appointment are practical ones¹⁰. Take painkillers such as ibuprofen or paracetamol, with a pharmacist's advice if you are unsure, and no aspirin for anyone under 16¹⁰. Eat soft foods and chew on the other side. Use a soft toothbrush and avoid flossing around the sore tooth, and skip anything sweet, very hot or very cold.

How soon should you be seen, and what should you say?

Book an ordinary appointment now, before any toothpaste trial, and go sooner if a sign in the table applies. Every row below comes from the NHS and Oral Health Foundation pages as they read on the day this page was written⁹¹⁹¹⁰.

The category's biggest brand says much the same about its own tubes. Sensodyne's UK FAQ tells people whose pain or sensitivity still persists to see a dentist, "as your sensitive teeth may indicate a different problem", and gives "a cracked tooth or a cavity (tooth decay)" as examples of tooth pain that is not sensitivity.

This page compares ingredients and stated actions only, not clinical performance, based on what each brand states about its own formula. Prices and formulations may change; always check the pack.

What does waiting risk? Nobody appears to have measured it for a tooth that has turned sensitive, and this page will not invent a figure. The nearest evidence is for cracked teeth that were found. In a retrospective cohort clinical study of 199 cracked teeth in Singapore whose nerve was judged able to recover, 71% were still healthy three years later and 29.1% went on to an irreversibly inflamed or dead nerve, more often in teeth that never received a crown²⁰. Every one of those teeth had already been examined, fitted with a protective band on the day and sent on for treatment. A tooth gets that only once someone has looked at it, which is the point of the appointment.

Take one sentence with you, in your own words: which tooth, for how long, what sets it off, whether the pain stops when the trigger stops, whether biting hurts, and what you have been brushing with. Something like: "One tooth at the back on the upper right has hurt with cold drinks for about ten days, the twinge goes within a few seconds, it does not hurt to bite, and I started a sensitivity toothpaste last week." The page on what a dentist checks for sensitive teeth walks through the examination that follows. If the sensitivity has arrived across several teeth at once rather than in one, the Journal's article why are my teeth suddenly sensitive is the better place to start.

Frequently asked questions

Will S3 fix one sensitive tooth?

If a dentist examines the tooth and finds exposed dentine and nothing else, a sensitivity toothpaste may help it over a few weeks like any other, and S3 is made for exactly that kind of everyday use, twice a day across the whole mouth. What no trial can tell you in advance is whether your tooth is that kind, because the trials left out the teeth where something else was going on¹. The examination can. If it finds a crack, decay or a failing filling, the dentist's treatment comes first.

Is it normal for one tooth to be sensitive after a filling?

It is common enough to have been counted, and worth reporting if it lasts or grows. In a practice-based cohort clinical study of 665 fillings for decay in 602 patients in the United States, 18% of the 491 teeth reported on four weeks later had appreciable sensitivity; the filling had removed the sensitivity in 63% of the teeth that had it beforehand, and new sensitivity appeared in 10% of teeth that had none²¹. The Journal's guide to tooth sensitivity after a filling covers what usually settles, and a filled tooth that hurts on biting goes back to the dentist who placed the filling.

Can a sensitivity toothpaste hide a problem?

Nobody has measured whether it does. A PubMed search run for this page in September 2026, pairing desensitising toothpastes with masking, delayed diagnosis and misdiagnosis, returned two records, and neither studied it. The risk this page can point to is the waiting: weeks spent giving a paste its chance are weeks in which a crack or decay is not being looked at, whatever the paste does to the twinge.

Should I use a sensitivity toothpaste differently on the sore tooth?

No. Brush the whole mouth as usual, twice a day, and spit out. The trials in the table, each funded by or written with the manufacturer of a paste it tested, used their pastes as ordinary toothpastes for brushing⁴⁵⁶¹⁶. Nothing on this page supports treating one tooth in a different way; the appointment is what that tooth needs.

What will a dentist do about one sensitive tooth?

Find out which tooth it is and why before choosing anything. If it turns out to have exposed dentine and nothing more, the Oral Health Foundation says a dentist may put a desensitising treatment on it, suggest a high-fluoride toothpaste, cover a worn patch near the gum with a filling, or treat gum disease⁹. The page on dental treatments for sensitivity goes through those options and how long each lasts.