Sensitive teeth usually happen when the softer layer under your enamel, called dentine, becomes exposed, often because of gum recession, enamel wear or a problem such as decay or a cracked tooth. Many cases improve with a desensitising toothpaste and changes to brushing and diet, but sensitivity that is severe, lingers or is limited to one tooth should be checked by a dentist.
What causes tooth sensitivity?
Your teeth are covered by enamel above the gumline and by a thin layer called cementum on the roots. Underneath is dentine, which contains thousands of microscopic tubes running towards the nerve. When dentine is exposed, hot, cold, sweet or acidic things, or even a breath of cold air, can move the fluid inside those tubes and trigger a short, sharp twinge.
This type of sensitivity is called dentine hypersensitivity. It is very common, particularly in adults, and it often comes and goes.
Common causes of sensitive teeth
Gum recession
When gums pull back, the root surfaces are exposed. Roots are not protected by enamel, so they are more prone to sensitivity. Recession can be caused by gum disease, brushing too hard, a thin gum type, orthodontic tooth movement or simply ageing.
Enamel erosion
Frequent exposure to acid gradually dissolves enamel. Common sources include soft drinks, sports and energy drinks, fruit juice, kombucha, citrus, wine and vinegar-based foods. Acid reflux and frequent vomiting can also erode teeth from the inside.
Abrasion from brushing
Scrubbing hard with a firm brush, especially side to side, can wear notches near the gumline over time. Very abrasive whitening toothpastes can add to the problem.
Grinding and clenching
Night-time grinding wears down biting surfaces and can cause small cracks and flexing at the necks of teeth, all of which can make teeth more sensitive.
Decay, cracks and failing fillings
Not all sensitivity is surface-level. A cavity, a crack or a leaking old filling can let stimuli reach the nerve more directly. These usually affect one tooth, and the sensitivity may be sharper, linger after the trigger or come with pain when biting.
After dental treatment
Some temporary sensitivity is common after a professional clean, a new filling, or teeth whitening. It usually fades within days to a few weeks. If it is getting worse rather than better, let your dentist know.
Is it sensitivity or something more serious?
A useful rule of thumb is to notice how long the sensation lasts and where it is.
- Brief, sharp twinge that stops within seconds of removing the trigger, affecting several teeth: often dentine hypersensitivity.
- Pain that lingers for more than 30 seconds or so after hot or cold, throbbing pain, or pain that wakes you at night: may indicate inflammation of the nerve and needs prompt assessment.
- Sharp pain when biting or releasing, especially on one tooth: can be a sign of a cracked tooth.
- Sensitivity with swelling, a pimple on the gum or a bad taste: may indicate infection.
Only an examination, sometimes with X-rays, can tell the difference reliably.
What you can do at home
Use a desensitising toothpaste
Toothpastes for sensitive teeth work either by calming the nerve response (for example, potassium nitrate) or by blocking the open tubes in the dentine (for example, stannous fluoride or arginine-based formulas). They usually take two to four weeks of twice-daily use to work, and they need to be used continuously to keep working.
A helpful tip is to spit after brushing rather than rinsing with water, so the active ingredients stay on your teeth. You can also smear a small amount over sensitive areas before bed.
Brush gently
Use a soft-bristled brush and gentle pressure. Some electric toothbrushes have a pressure sensor, which can help if you tend to brush hard.
Choose your other products carefully
Highly abrasive whitening toothpastes and charcoal products can wear exposed dentine further, so it is sensible to avoid them while your teeth are sensitive. Some mouthwashes contain alcohol or acids that can sting sensitive areas; a fluoride mouthwash used at a different time from brushing can be a gentler option. If you are using a take-home whitening kit and sensitivity flares, pause it and ask your dentist for advice rather than pushing through.
Reduce acid exposure
- Limit acidic drinks and have them with meals rather than sipping throughout the day.
- Use a straw for acidic drinks where practical.
- Rinse with water after acidic food or drink, and wait about an hour before brushing.
- If you have reflux, talk to your GP about managing it.
Treatments your dentist may recommend
Treatment depends on the cause, so the first step is finding out why your teeth are sensitive.
Professional desensitising treatments
Your dentist can apply a high-concentration fluoride varnish or a desensitising agent to seal exposed dentine. These are quick and often helpful, though they may need to be repeated, and results vary. A high-fluoride toothpaste may also be prescribed for home use.
Bonding or fillings
Where there are notches at the gumline, cavities or failing fillings, a tooth-coloured filling can cover the exposed area or restore the tooth. Fillings can occasionally be sensitive for a while afterwards, and like any restoration they will eventually need maintenance or replacement. Our fillings and restorations page explains the options. The fee depends on the size and number of surfaces involved, and a written estimate is given after assessment.
Treating gum problems
If gum disease is contributing to recession, a professional clean and better home care help stop it progressing. You can read more about a professional dental clean on our site. Where recession is significant, a gum graft to cover exposed roots may be an option, and you may be referred to a specialist periodontist.
Night guards
If grinding is a factor, a custom-made splint worn at night can protect the teeth from further wear.
Root canal treatment
In the uncommon situation where severe, persistent sensitivity is caused by an irreversibly damaged nerve, root canal treatment may be recommended. Your dentist will explain the benefits and risks and any alternatives.
When to see a dentist
Book a check-up if sensitivity has not improved after a month of using a sensitive toothpaste, if it is getting worse, or if it affects one tooth in particular. See a dentist promptly if the pain lingers, throbs, wakes you at night or comes with swelling, as these can be signs of a problem with the nerve or an infection.
At our Macquarie Park practice, your dentist will check for decay, cracks, recession and wear, and explain what is likely to help in your situation.
Frequently asked questions
Why are my teeth suddenly sensitive?
Sudden sensitivity can follow recent dental treatment, whitening, a change in diet or brushing habits, or a new problem such as a cavity or crack. If it does not settle within a couple of weeks, have it checked.
How long does sensitive toothpaste take to work?
Most desensitising toothpastes take around two to four weeks of twice-daily use. They need to be used continuously, as sensitivity often returns when you stop.
Can sensitive teeth go away on their own?
Sometimes, particularly after dental treatment. Sensitivity from exposed roots or enamel wear usually needs ongoing management, and sensitivity from decay or a crack needs treatment.
Is tooth sensitivity a sign of a cavity?
It can be, especially if one tooth is affected or the sensation lingers. Sensitivity can also come from exposed roots or enamel wear, so an examination is the only reliable way to tell.
Does whitening cause sensitive teeth?
Whitening commonly causes temporary sensitivity, which usually fades within days. Your dentist can adjust the approach or recommend a desensitising product if you are prone to it.
You do not have to put up with sensitive teeth. Call North Ryde Dentistry on (02) 8090 1102 or book an appointment.
This article is general information only and is not a substitute for advice from your own dentist. Any treatment carries risks; your dentist will discuss whether it is suitable for you.