Why are my teeth sensitive?

How sensitivity happens

Enamel covers the crown of each tooth, and gum tissue protects the root. Underneath is dentin, which contains thousands of tiny channels leading toward the nerve. When dentin is exposed, cold, heat, sweetness or even air can reach the nerve through these channels and cause a short, sharp pain.

Sensitivity often comes and goes. It can flare in winter when you breathe cold air, after a change in toothpaste, or during stressful periods when you clench more. Keeping notes on what triggers it, which teeth react and how long the pain lasts helps your dentist narrow down the cause.

Common causes

• Gums pulling back from the teeth with age or gum disease
• Brushing too hard or using a hard-bristled brush
• Enamel worn away by acidic drinks, sports drinks or reflux
• Grinding or clenching, often at night
• A cavity, a cracked tooth or a leaking filling
• Temporary sensitivity after a cleaning, filling or whitening

What you can try at home

Desensitising toothpastes work in two main ways. Some contain potassium nitrate, which calms the nerve. Others contain stannous fluoride or arginine, which plug the tiny channels in dentin. If one type doesn't help after a few weeks, another may.

• Use a desensitising toothpaste twice a day for at least two weeks
• Switch to a soft-bristled brush and use gentle strokes
• Rinse with water after acidic foods and wait before brushing
• Avoid whitening products while your teeth are sensitive
• Dab a little desensitising toothpaste on the sore area at night and leave it on

What your dentist may suggest

After finding the cause, treatment might be a fluoride varnish, a bonded coating over exposed root surfaces, or a filling to repair a cavity or worn spot. If grinding is the cause, a custom night guard can protect your teeth while you sleep. At our office, a soft-tissue laser may also be used as one option to help settle sensitive areas.

For gum recession that keeps progressing, you may be referred to a periodontist to discuss gum grafting.

When sensitivity is a warning sign

Short twinges that fade within seconds are usually mild. Pain that lasts more than a few seconds after the trigger is gone, throbs on its own, or comes with swelling can mean the nerve is inflamed or infected. Call for an exam, as a root canal or other care may be needed.

Related services

More patient guides

• What causes bad breath, and what can you do about it?
• Canker sore or cold sore: how to tell the difference
• Canadian Dental Care Plan: who qualifies and how it works
• Laser treatment for cold sores: your questions answered

Trusted health information

• Caring for your teeth and mouth (Government of Canada)
• Fluoride and oral health (Health Canada)
• Oral health (Government of Canada)