Sharp and brief, or dull and lingering: the pain pattern that tells sensitivity from something else.

Sharp, brief pain that arrives with a trigger and is gone within seconds is the pattern of sensitivity from exposed dentine; pain that lingers, comes on by itself, wakes you, sits in one tooth that hurts to bite on, or comes with swelling is something else, and it points to a dentist. UK guidance already sends those other patterns through one of three doors, A&E, an urgent dental appointment or a routine one, and leaves only the fourth, care at home, to the shelf. A sensitivity toothpaste such as S3 Sensitivity Science™ is built for the first pattern only, pairing potassium nitrate for the nerve with hydroxyapatite for the open tubules. No checklist has been shown to tell dentine sensitivity from an inflamed nerve without an examination, so the six questions on this page are for choosing a door, not for making a diagnosis.

What was checked20 peer-reviewed studies, the NHS, NICE Clinical Knowledge Summaries and the Oral Health Foundation

What does sensitivity feel like, and what does something else feel like?

Sensitivity from exposed dentine is short and provoked; the pains that point elsewhere are longer, deeper, or arrive with nothing to provoke them. Dentine lies under the enamel and over the root, and it is threaded with tiny channels that lead to the nerve. When enamel wears away or a gum shrinks back, those channels are exposed, and heat, cold or sweetness can reach the nerve through them, as can brushing a particular tooth⁵. The widely accepted explanation is that the stimulus moves the fluid inside the open channels, and the moving fluid is what the nerve reports⁶. What a person feels is a jolt: sharp, brief, and fading as the cold drink or the bristles move on.

The Oral Health Foundation's own description is less tidy than that, and it is worth reading exactly. Its page on sensitive teeth says the pain can feel like a quick, sharp pain or a longer ache, that it is usually short but can sometimes last longer, and that sensitive teeth can be a sign of a dental problem that should not be ignored⁵. The two patterns in this page's title overlap at their edges, then, and the overlap is exactly where a reader on their own cannot tell them apart.

Clinicians find those edges hard too. A Canadian advisory board of dentists and hygienists wrote its 2003 consensus review of diagnosis and management because the evidence on diagnosing the condition was neither clear nor strong, and an educational needs survey had shown confusion about how to diagnose it⁷. Seventeen years later an evidence-based overview written for dental practitioners still found no universally accepted guideline for separating dentine hypersensitivity from the conditions that imitate it, several of which resemble it at one stage or another of their course⁶.

Nobody has handed the reader a validated way to do it at home, either. A PubMed search run for this page in September 2026, pairing sensitivity or toothache with questionnaires, checklists or self-report, with validation or accuracy, and with pulpitis or differential diagnosis, returned four records. The nearest thing to a home check among them is a 16-item questionnaire from a London dental school: in a clinical study that validated it against diagnosis by examination, it placed 89.7% of dental pain patients in the right one of three groups². Its groups are not the ones a worried reader needs, though, because dentine hypersensitivity shares a group with reversible pulpitis, the inflammation of the nerve that can still settle, while irreversible pulpitis shares one with inflammation around the root tip². Its authors propose it for population surveys and for triage of people seeking treatment, and nothing in that is a person deciding alone whether a tooth can wait². So the six questions below are a way to pick a door. None of them, singly or together, is a diagnosis.

What people say about their own teeth and what an examiner finds do not line up well either. In a cross-sectional clinical study of 380 patients at a Brazilian university dental clinic, 41.7% said they had sensitive teeth, while 88.7% were diagnosed with dentine hypersensitivity once their teeth were tested⁸. That is a gap between asking and testing in one young clinic population, not a prevalence, and it is a reason to let the questions below point to someone who can test.

The six questions sit in the table first, and the sections after it take them one at a time. The columns describe pains, not products, and the last column says how strong the evidence behind each row is.

What sets it off, and how long does it last?

A sensitive tooth answers a stimulus and settles when the stimulus goes; what separates the other patterns is less the trigger than the time the pain takes to leave. The triggers overlap more than most people expect. Cold is the classic one, yet the Oral Health Foundation's toothache guidance gives three quite different causes for a sharp pain when you eat or drink something cold: receding gums, a filling that is lost or worn, and a tooth that is cracked or broken⁹. Only the first of those is a question for the shelf. The NHS adds that a dental abscess can make a tooth sensitive to hot or cold food and drink as well¹⁵.

Duration is where the measurement lives. In a cross-sectional clinical study, examiners timed how long the back teeth of 60 adults went on hurting after a standard cold test: roughly four to five seconds in the group diagnosed with pulpitis that could still settle, six seconds or more in the group whose pulpitis could not, and the longer the response, the more of an inflammatory enzyme the dentine held¹⁰. Two details of that study matter more than its numbers. It had no group with sensitive dentine at all, only healthy pulps and the two kinds of pulpitis, so even four or five seconds describes an inflamed nerve rather than the jolt this page began with¹⁰. And the cold was applied by an examiner to one tooth kept dry and apart from its neighbours, so no count of seconds on this page is something to try with a drink¹⁰.

The words you use for the pain carry information too, so use your own when you book. Among 228 people seen for acute toothache in a cross-sectional clinical study, a tooth that hurt when tapped went with pain described as throbbing and radiating and rated as more intense overall, and a tooth that could still feel cold went with a shooting quality¹⁷.

The long version of the pain has its own heading in the charity's toothache guidance: an ache that lingers, comes and goes, and needs painkillers may mean the nerve inside the tooth is irritated, damaged or dying, in the Oral Health Foundation's words, and it needs a dentist's further checks⁹. The page on sensitivity that lingers after the trigger has gone takes that pattern apart, and the page on teeth sensitive to hot and cold at the same time covers the timing test in detail; the Journal explains why cold hurts your teeth in the first place. This page needs only the rule both of them arrive at. A pain that outlasts its cause is a pain for an appointment.

Does it come on its own, or wake you?

Sensitivity from exposed dentine is defined by its trigger, so it has no reason to arrive unprovoked; pain that does is a reason to see a dentist, and severe pain that costs you sleep is treated by UK guidance as urgent. The first part of that is a consequence of the definition and not a finding. Nobody appears to have asked people with dentine hypersensitivity whether it wakes them: a PubMed search for this group of pages, pairing the condition with sleep, night and waking, returned two records in September 2026, and neither was about it.

The NHS is specific about the urgent part. On its urgent list is severe tooth or mouth pain that is affecting your sleep or daily activities and is not helped by paracetamol or ibuprofen, and so, less obviously, is pain that painkillers do help but that is not going away; for both it says to ask a dentist for an urgent appointment or contact NHS 111, and that urgent treatment should be offered within 24 hours or seven days, depending on the symptoms⁴. The Oral Health Foundation gets to the same place from the pain itself, placing severe pain that keeps you awake, throbs or does not let up, and does not improve with painkillers, under the possibility of an infection or a dental abscess, and telling people to contact a dentist urgently⁹.

What unprovoked pain looks like when it comes from the nerve has been measured in inflamed pulps. In a cross-sectional clinical study of 35 patients with symptomatic irreversible pulpitis, the 23 whose pain was felt away from the tooth reported stronger spontaneous tooth pain over the previous day than the 12 whose pain stayed put, and they felt cold for longer and more intensely even in a healthy tooth on the opposite side¹¹. Pain that comes by itself and pain that is hard to pin to one tooth travel together in that study. Cracks can produce unprovoked pain as well: in a practice-based observational clinical study of 2,858 back teeth with a visible crack, 11% hurt with no trigger at all¹⁶.

Night pain has its own page, on tooth pain at night. For this one the door is enough: pain that comes without a trigger goes to a dentist rather than to the shelf, and if it is severe and costs you sleep despite painkillers, to an urgent appointment through your dental practice or, if it is closed or you have none, NHS 111⁴¹⁴.

Is it one tooth or several, and does biting hurt?

Sensitivity from exposed dentine usually shows on several teeth at once, while a single tooth that stands out, above all one that hurts to bite on, is the shape a dentist wants to see. In a cross-sectional clinical study that examined 3,551 adults in seven European countries, funded by Haleon, a maker of sensitivity toothpastes, sensitivity was most common in the lower front teeth and on the cheek-facing surfaces, where it went with erosive wear and receding gums¹².

One inflamed tooth can also make healthy teeth near it misbehave, which muddies the count. In a clinical study of 64 patients with an irreversibly inflamed pulp, the healthy tooth next door and the matching healthy tooth in the opposite jaw both over-responded to a cold test, and both settled once the inflamed tooth had been root-treated¹³. A sensation spread across several teeth does not, on its own, settle whether several teeth are sensitive.

Biting pain is the sign people attach to a cracked tooth, and it is real, but it is not the usual one. Of the 2,858 cracked back teeth in that practice-based clinical study, fewer than half caused any symptom; cold was the trigger in 37% and biting in only 16%¹⁶. Because every tooth in it was chosen for having a crack, the result cannot be read backwards into odds for a cold-sensitive tooth; what it does show is that a crack can pass for sensitivity¹⁶.

Guidance draws its line at the single tooth. The Oral Health Foundation sends a tooth that is the only one affected to a dentist, and says pain on biting, which can come from a crack, decay or a loose filling, should always be checked⁵⁹. A broken or loose filling or crown is on the NHS urgent list in its own right⁴. The page on one tooth that has suddenly become sensitive sets out how a crack, a filling, decay and a patch of recession each tend to present. The door here is usually a routine appointment, and an urgent one if a filling has broken or the pain will not go.

What else comes with it: swelling, a taste, a fever?

Nothing comes with it, if it is sensitivity. Swelling, a bad taste, a raised temperature or swollen glands alongside tooth pain are signs the NHS links to a dental abscess, and they move the door from the shelf to an urgent appointment, or to A&E.

The NHS page on dental abscess lists intense toothache or gum pain, redness inside the mouth or on the face, a bad taste, difficulty opening the mouth or chewing, a swollen face or jaw, swollen glands in the neck and a high temperature, and it lists sensitivity to hot or cold food and drink in the affected area among the same symptoms¹⁵. That last item is why a twinge to cold, by itself, never rules an infection out. The same page says an abscess will not go away on its own and is treated by a dentist, who drains the pus, sometimes followed by root canal treatment or removal of the tooth¹⁵.

The A&E signs are narrow and plain. Call 999 or go to A&E, the abscess page says, if breathing, speaking or swallowing is hard, if an eye is swollen or painful or eyesight suddenly changes, if there is a lot of swelling in the mouth, or if the mouth is hard to open¹⁵. The toothache page adds swelling around the eye or in the neck¹⁴. Both tell you not to drive yourself there.

The two NHS pages do not grade every sign the same way. The toothache page puts a high temperature, a bad taste and a swollen cheek or jaw under non-urgent advice to see a dentist, while the abscess page tells anyone who thinks they have an abscess to ask for an urgent appointment or contact NHS 111¹⁴¹⁵. This page puts those signs behind the urgent door, the more cautious of the two readings. The Oral Health Foundation adds a clock: facial swelling, swelling that is getting bigger, or significant pain with swelling means a same-day appointment, and swelling that affects breathing, swallowing or vision, spreads towards the eye or neck, or arrives with a fever and severe pain means emergency care⁹.

An infection is treated in the dental chair, and a paste that took the edge off the cold would only mute a warning. The page on sensitivity with swelling or a bad taste goes through those signs one by one.

Why does it feel sudden?

Usually because the change behind sensitivity has been building quietly, and what is sudden is the day it crosses into notice; the things that genuinely start overnight are the ones on the dentist doors. The condition keeps company with slow processes. A cross-sectional clinical study of 3,551 adults across seven European countries, funded by Haleon, found some erosive tooth wear in 97.6% and some gum recession in 87.9% on examination, found dentine hypersensitivity associated with both, and found it growing more common through young adulthood before declining after roughly the late thirties to late forties¹⁸. A cross-sectional survey can show that sensitivity and wear travel together; it cannot show that one caused the other, or how fast either arrived.

Nothing this page could find in print follows sensitivity from its start. A PubMed search run in September 2026, pairing dentine hypersensitivity with onset, sudden or incidence and with cohort or longitudinal designs, returned two records: a review of complications under inlay-retained bridges and a review of root sensitivity after gum treatment. Neither followed people from comfortable teeth to sensitive ones. So this page writes "sudden" as the moment of noticing, and makes no claim about how quickly the underlying change happened.

Some things do start on a particular day. A filling that has come loose or broken, a crack and an infection all appear on the NHS pages above⁴¹⁴¹⁵. Dental work can change a tooth quickly: a 2019 clinical review for UK primary dental care notes that restorative procedures can rapidly alter the enamel and dentine, inflaming the pulp and making the tooth more sensitive to temperature¹⁹. The Oral Health Foundation lists tooth whitening among the causes, usually with only temporary sensitivity⁵. Sensitivity after a scale and polish or deeper gum treatment has its own page, on what a hygienist can do for sensitive teeth, and a tooth that starts hurting after any treatment is worth reporting to the practice that did it.

Decay is not sudden either, though it can feel that way. It takes time to reach the dentine, and the sensitivity it brings can appear abruptly once it does; fluoride and hydroxyapatite act on early, softened enamel, and a cavity that has formed needs a filling, which is why a sweet trigger in one particular tooth deserves the page on sweet sensitivity and decay. The Journal's short piece on why teeth suddenly become sensitive gives the everyday causes and its own list of reasons to see a dentist, and the two causes of sensitive teeth the mechanism; this page adds the evidence and the limits behind that list. If sensitivity you already had keeps growing despite a sensitivity paste, start with the page on what to rule out first.

Which door does your pattern point to?

There are four doors, from most to least urgent: A&E or 999, an urgent dental appointment within a day or a week, a routine appointment, and care at home with a daily paste judged over weeks; the first three come from the NHS pages, and the fourth is what remains when none of their signs applies⁴. The table maps the six answers onto them sign by sign, with the page each sign comes from.

The doors are a way of sorting, and even the professionals' tools misfire. The tests a dentist uses to judge a pulp misclassify a real share of teeth: a 2022 systematic review and meta-analysis found a pooled sensitivity of 79% and specificity of 82% for the cold test, and 54% and 75% for the heat test, and rated none of its included studies good on quality³. The labels those tests feed into are good but not perfect. In a clinical study of 95 teeth from one general practice, examined under the microscope after extraction, a clinical diagnosis of a healthy or recoverable pulp matched the tissue in 57 of 59 teeth, and a diagnosis of irreversible pulpitis matched in 27 of 32²⁰. People and examiners also disagree about the teeth themselves, as the Brazilian clinic figures earlier on this page show.

None of that makes the appointment pointless. It is the reason the answer to a doubtful pattern is a dentist's history, examination and tests taken together, not a verdict reached at home, and the page on what a dentist checks for sensitive teeth walks through that visit. Most adults pay for NHS dental appointments, the NHS notes, and the page on free and low-cost NHS dental options sets out the charges and who is exempt⁴. While you wait, the NHS advises painkillers such as ibuprofen or paracetamol, with a pharmacist's advice and no aspirin for children under 16, and keeping away from food that is sweet, very hot or very cold¹⁴; the page on what helps tooth nerve pain tonight covers the rest.

Where does a paste like S3 fit in the pattern?

Behind the fourth door only, where it has a specific job. When the pain is the short, provoked kind, the tooth has two things wrong at the same time: a nerve that reacts too readily, and dentine tubules left open to the mouth. S3 gives each problem its own ingredient, with potassium for the nerve, nano-hydroxyapatite for the inside of the tubule and biomimetic hydroxyapatite for the surface, none of them able to stand in for another. It is a paste for twice-daily use whose actives build rather than switch on, so S3 starts working from the first brush and is judged at two to four weeks.

Of the four doors on this page, only one leads to a toothpaste, and no tube, this one included, belongs behind the other three. Nothing in S3 is designed for a crack, decay that has become a cavity, an inflamed or infected pulp, sinus pain or grinding, and nobody should wait on it before using a door that sends them to a dentist.

Nobody screens the choice of paste, either. In an industry-funded qualitative clinical study of 18 Australian adults with confirmed sensitivity, 89% reported using a desensitising toothpaste, every one of them had picked it themselves, and none had been proactively screened for the condition by a dentist²¹. The shelf is where most people start, which is why the six questions belong before it.

Getting better on a sensitivity paste does not prove the pain was sensitivity²². Some of what any treatment does in its first weeks is the response to being treated at all: in a six-month randomised, placebo-controlled crossover trial of 35 patients, water applied as the placebo cut pain from an air blast by 20% straight away and 36% at six months, beside 35% and 55% for the professionally applied calcium-phosphate paste it was tested against²³. In a randomised split-mouth study of 22 adults, the investigators found that a periodontal dressing laid over sensitive teeth reduced pain to a thermal stimulus by 95% and to an air stimulus by 85% compared with no dressing, and concluded that sensory factors alter how this pain is perceived²². Neither figure is a toothpaste result, and neither says a paste works by suggestion. Together they say that improvement cannot be read backwards into a diagnosis, and that ruling out the other causes is a dentist's job.

The clocks differ because they answer different questions. The Oral Health Foundation says to see a dentist if a sharp pain to cold is no better after two weeks of a desensitising toothpaste⁹; the consensus guidelines for sensitivity trials recommend that most last eight weeks¹; S3's own wording is two to four weeks. None of those clocks applies to a pain behind the other three doors, and the page on how long to try a sensitivity toothpaste before seeing a dentist lays them side by side.

When is it not a tooth at all?

Sometimes the ache is felt in a tooth and the cause lies elsewhere: a sinus, a jaw joint or the chewing muscles can each produce it. A 2014 systematic review defines this kind of toothache as pain in a tooth that nothing clinically evident in the tooth or gum explains, and groups its causes into eight kinds, among them muscle pain referred to the teeth, nerve pain, neurovascular pain, sinus pain and pain referred from the heart; its authors' main recommendation is to treat the real cause and avoid unnecessary dental treatment²⁴. A UK oral surgeon's 2020 review makes the same point from the other side: jaw joint and muscle disorders, headaches, nerve injury and referred pain can all pass for toothache, toothache can pass for them, and the confusion leads to late and wrong diagnoses, repeated antibiotics and surgery that did not need doing²⁵.

The sinus is the everyday example. On the NHS page for sinusitis, toothache appears in the second list of symptoms, below pain and tenderness around the cheeks, eyes or forehead, a blocked or runny nose and a raised temperature; the page says the infection often follows a cold or flu, usually clears up on its own within four weeks, and can be taken to a pharmacist first²⁶. Jaw problems present differently. The NHS describes temporomandibular disorder as pain around the jaw, ear and temple, with clicking or popping and difficulty opening the mouth, often worse when chewing or under stress, and its urgent list, which includes a jaw that locks or will not open fully, points to a GP or NHS 111²⁷. Grinding sits across both: the NHS says it can wear down or break teeth and increase sensitivity, and cause pain in the jaw, face or ear, and it tells people who grind and have damaged or sensitive teeth to see a dentist²⁸.

The list clinicians work through is longer. NICE's Clinical Knowledge Summary on dental abscess, last revised in May 2023, names among the conditions an abscess can be confused with sinusitis, acute middle-ear infection, salivary gland problems, temporomandibular disorders, trigeminal neuralgia or atypical facial pain, giant cell arteritis and acute coronary syndrome, and says the list rests on expert opinion in review articles²⁹. None of these is something to work out from a web page. A tooth that a dentist has examined and found sound, and that still aches, is a reason to go back, or to a GP, with the other symptoms written down.

Frequently asked questions

If S3 helps, does that prove my pain was sensitivity?

No. Part of what any treatment achieves in its first weeks is the response to being treated: in one randomised placebo-controlled trial of an in-surgery desensitising paste, water alone reduced air-blast pain by a fifth straight away²³, and a split-mouth study concluded that sensory factors alter how this pain is felt²². S3 is judged at two to four weeks, but feeling better over that time does not rule out a crack, decay or an inflamed pulp; only an examination can.

Why are my teeth suddenly sensitive when nothing seems to have changed?

Usually something has been changing slowly. In an industry-funded cross-sectional clinical study of 3,551 adults, sensitivity was associated with enamel wear and gum recession, changes that can build without being felt, so the day it is first felt can seem like the day it began¹⁸. What does change overnight is a crack, a lost or broken filling or an infection, and those are reasons to call a practice, not to wait on a paste⁴¹⁵.

Should I see a GP or a dentist about tooth pain?

A dentist. The NHS says a GP will not be able to give dental treatment, and that when your practice is closed or you have no dentist the route is NHS 111¹⁴. The exceptions are pains that are not dental: sinusitis can be taken to a pharmacist or a GP, and a jaw that locks or will not open goes to a GP or NHS 111²⁶²⁷. Swelling that affects breathing or swallowing goes to A&E, whoever you were planning to see¹⁴.

Is toothache from a blocked sinus common?

The NHS lists toothache among the other symptoms of sinusitis, after the main ones, and gives no figure for how often it happens; this page does not have one either²⁶. What helps is the company it keeps: an ache that arrives with a cold, a blocked nose and tenderness over the cheeks is a different pattern from a twinge that comes with every cold drink. If the ache stays once the sinus symptoms have cleared, a dentist should look at the tooth.