A quick, sharp zing from cold water that fades within seconds is the classic sign of sensitive dentine, and it is usually a problem of exposure rather than damage deep inside the tooth. Something has worn away or pulled back from the surface, leaving the more porous layer underneath open to temperature changes. Finding out what caused that exposure is what decides the treatment, and a few patterns of pain point to something more serious that should not be left.
Written by Dr James Tran, dentist at Lumi Dental.
How common sensitive teeth are
Estimates vary a lot depending on who is studied and how. A 2019 meta-analysis in the Journal of Dentistry (Favaro Zeola and colleagues), which pooled 77 studies, put the best overall estimate at about 11.5% of people, while individual studies reported anywhere from 1.3% to 92.1%. Studies of younger adults and of patients attending specialist practices tended to report higher figures. Whatever the true number, it is one of the most common reasons people mention a tooth at a check-up.
Why exposed dentine hurts
Under the enamel of the crown, and under the thin covering of the root, is dentine. It is threaded with thousands of microscopic tubes that run towards the nerve in the centre of the tooth. When those tubes are open at the surface, cold, heat, sweet or acidic food, or a puff of air can make the fluid inside them move, and nerve endings near the pulp pick that movement up as a short, sharp pain.
The clinical name is dentine hypersensitivity. Its defining feature is that the pain is brief and stops soon after the trigger is gone. Pain that lingers, throbs by itself or wakes you at night is more likely to be coming from inflammation in the pulp, which is a different problem with different treatment.
Gum recession and worn enamel are the usual culprits
Most sensitive teeth come down to one of two kinds of exposure, and many people have a bit of both.
Gums that have pulled back
When the gum recedes, part of the root is uncovered. Roots have no enamel, so the dentine there is close to the surface and easily stimulated. Recession can follow gum disease, orthodontic tooth movement, a naturally thin gum type or heavy brushing in one spot, and it tends to become more common with age. Cold sensitivity right at the gum line is a typical sign.
Enamel worn by acid or wear
Frequent acidic food and drink, such as citrus, soft drinks, sparkling water, wine and kombucha, softens the enamel surface, and over years this can thin it and expose dentine. Acid from reflux or frequent vomiting does the same from the inside. Grinding and clenching wear the biting surfaces flat, and wedge-shaped notches can form at the gum line, often from a mix of brushing, acid and possibly biting forces.
Other causes worth ruling out
Several other problems can feel like ordinary sensitivity at first.
- Decay. A small cavity often first shows up as a twinge with sweet or cold food in one tooth. Found early, it usually needs only a filling.
- A cracked tooth. Cracks often cause sharp pain when biting from a certain angle, or when letting go of a bite, rather than with temperature alone. They are more common in heavily filled back teeth.
- Recent dental work. Some sensitivity after a new filling, a deep clean or whitening is common and usually settles over days to weeks. Sensitivity that is getting worse rather than better should be checked.
- Gum disease. Inflamed gums can recede and expose roots. Bleeding when brushing, bad breath or a tooth that feels loose are other clues. Our article on gum disease in Australia covers the warning signs.
- Whitening. Peroxide gels can cause short-lived twinges across several teeth, which usually settle within a few days of finishing or pausing treatment. Our guide to in-chair and take-home whitening explains the options.
Signs that it is more than sensitivity
Book an appointment within days rather than waiting for your next check-up if you notice:
- Pain that lingers well after the hot or cold trigger has gone.
- Throbbing or aching that starts on its own.
- Pain that wakes you at night.
- Sharp pain when biting on one particular tooth.
- Sensitivity to heat more than cold.
- Swelling, a bad taste or a pimple on the gum near the tooth.
- A tooth that was painful and has now gone numb, which can mean the nerve has died and still needs treatment.
These can point to a tooth that needs a filling, a crown, root canal treatment or, in some cases, removal. Earlier treatment is usually simpler.
Treatment depends on the cause
For sensitivity from exposed dentine with no other problem, the usual starting point is a desensitising toothpaste at home and a professionally applied product such as a fluoride varnish or a desensitising agent painted onto the sensitive areas. If the cause is structural, the tooth needs repairing.
| Cause | Common treatments |
|---|---|
| Exposed dentine from recession or wear | Desensitising toothpaste, fluoride varnish or a desensitising agent applied by your dentist or OHT |
| Deep notches or worn areas at the gum line | A tooth-coloured composite covering over the exposed area |
| Grinding or clenching | A custom night guard to protect the teeth from further wear |
| Decay | A filling |
| A cracked tooth | Often a crown to hold the tooth together |
| Irreversible inflammation of the nerve | Root canal treatment, or removal if the tooth cannot be saved |
How well desensitising toothpastes work is less clear-cut than the advertising suggests. A Cochrane review of potassium toothpastes (Poulsen and colleagues, 2006) found improvements in some measured sensitivity tests after six to eight weeks, but not in how people rated their own sensitivity, and concluded there was no clear evidence because the studies were small. Many people still find them helpful, and they are inexpensive and low risk, so they are a sensible first step. If sensitivity has not improved after several weeks of regular use, or a structural cause is found, the next step is usually treatment in the chair.
What treatment may cost
Fees depend on the cause and on what the examination finds. As typical market ranges in Sydney, not Lumi fees, a check-up and clean costs about $200 to $400, a crown about $1,500 to $2,500, and root canal treatment about $1,000 for a front tooth to $3,000 for a molar. Simpler options such as a desensitising application or a small filling cost less, and you will usually receive a written treatment plan, often by email, before anything is done.
Health fund extras usually cover part of general dental treatment. According to the Commonwealth Ombudsman's privatehealth.gov.au information, waiting periods are commonly about 2 months for general dental and 12 months for major dental, but each fund sets its own, so check with yours. Claims can be processed on the spot through HICAPS.
Habits that help at home
- Use a soft brush and light pressure. Harder bristles do not clean better and can add to wear at the gum line. An electric brush with a pressure sensor can help if you tend to scrub.
- Use a desensitising toothpaste twice a day and spit rather than rinse, so the ingredients stay on the teeth. Some people also dab a little on the sensitive spot at night.
- Cut down on how often you have acidic drinks and rinse with water afterwards. A 2024 scoping review in Caries Research (Fernández and colleagues) found that brushing with fluoride toothpaste soon after acid exposure did not add measurable wear in most studies, so there is no need to wait a set time.
- Deal with grinding early. Jaw stiffness on waking, headaches or flat, worn teeth are worth mentioning, as a night guard may help.
- Keep up regular cleans. A scale and clean removes plaque and tartar along the gum line and gives your dentist or OHT a chance to spot new recession or wear.
If sensitivity keeps coming back in different teeth, ask for a review of what is driving it. Acid wear, recession and grinding each need a different prevention plan.
Common questions
Why have my teeth suddenly become sensitive to cold?
New cold sensitivity in a tooth that was fine before is often from a small area of recession, a new crack or early decay. If it lasts more than a week or so, it is worth having checked.
How long does sensitivity last?
Sensitivity after a filling, clean or whitening usually settles within days to a few weeks. Sensitivity from exposed roots or worn enamel can take several weeks to improve with toothpaste and may need treatment in the chair.
Can sensitive teeth be fixed for good?
Often, yes, if the cause is found and dealt with. If sensitivity keeps returning, one of the causes, such as grinding or acid exposure, may still be active.
Does sensitivity mean I need a root canal?
Usually not. Most sensitivity is from exposed dentine and settles with simpler care. Root canal treatment is generally for a nerve that is irreversibly inflamed, with signs such as lingering pain, spontaneous throbbing or pain that wakes you.
Getting sensitive teeth checked
At Lumi Dental in Melrose Park, we look for the cause of sensitivity before deciding how to treat it. A new patient visit is a full 60 minutes, with an examination, clinical photographs, a gum check and any X-rays needed. For nervous patients, happy gas (relative analgesia) and IV sedation are available. Current new patient offers are on our current deals page.
About the author
Dr James Tran (BDent, AHPRA DEN0001934469) is a dentist at Lumi Dental. He focuses on conservative, evidence-based dentistry and on giving patients clear, honest answers about what their teeth actually need. More about his background and clinical philosophy is at drjamestran.com.au.
About Lumi Dental
Lumi Dental is an independent general and cosmetic dental practice at Melrose Central, Melrose Park NSW 2114. The practice offers general and family dentistry, cosmetic treatment, clear aligners and braces, dental implants, IV sedation and emergency appointments. It is open Monday to Saturday, until 9pm on Thursdays, with Sundays by appointment, and has free undercover parking.
This article is general information only and is not a substitute for personalised dental advice. Costs shown are typical Australian market ranges, not Lumi fees, and vary by individual case. Please book a consultation for advice specific to your teeth.
