Sensitive teeth: why cold hurts and what to do about it

A bite of ice cream, a sip of iced water, and a sharp jolt shoots through a tooth and is gone a moment later: that is tooth sensitivity. It comes from exposed dentine. Dentine contains thousands of tiny tubules leading straight to the pulp; when enamel or gum no longer covers it, cold, sweet or sour stimuli travel down those tubules and the pulp reacts. Most sensitivity can be managed at home, but some of it is a sign of a problem that needs a dentist.

Common causes

• Receding gums: the root surface is exposed, with no enamel to protect it. Often from brushing too hard, gum disease or age.
• Worn tooth necks: V-shaped notches at the gum line from horizontal, forceful brushing, a hard brush, or uneven biting forces.
• Acid erosion: soft drinks, lemon water, sour fruit, acid reflux, frequent vomiting.
• Decay, a leaking filling, a cracked tooth: sensitivity in one particular tooth.
• After dental treatment: scaling, fillings, whitening and crowns can cause temporary sensitivity for a few days to weeks.
• Grinding: worn biting surfaces, cracked enamel.
• Early pulp inflammation: sensitivity that lingers after the stimulus is gone, unlike ordinary sensitivity which stops at once.

Habits that make it worse

• Brushing side to side, pressing hard, with a hard-bristled brush.
• Highly abrasive toothpaste, or "whitening" pastes used with a lot of scrubbing.
• Brushing straight after acidic food or drink, while the enamel is softened. Wait about 30 minutes.
• Frequent soft drinks, lemon water or soda, held in the mouth.
• Chewing ice or biting hard objects.
• Using whitening products without guidance. If you want to whiten, Asahii makes custom trays from a mould of your teeth and prescribes the gel at the right concentration; see Teeth whitening.

What helps at home

• Desensitising toothpaste (potassium nitrate, stannous fluoride or arginine): used twice a day, every day, it works noticeably after a few weeks. A little can be dabbed on the sensitive spot before bed.
• A soft brush, small circles or gentle vibration at the gum line, no scrubbing across.
• Limit acidic and sweet food and drink; use a straw; rinse with water afterwards.
• Do not brush straight after acid; wait 30 minutes.
• A night guard if your dentist finds you grind.
• An alcohol-free fluoride mouthwash if your dentist recommends one.

What the dentist can do

When home care is not enough, the dentist can apply fluoride varnish or a dentine sealer, fill worn notches at the gum line, adjust the bite, or treat the cause, such as decay or gum inflammation. For significant gum recession, a gum graft may be considered. If the sensitivity comes from an inflamed pulp, root canal treatment is needed. All of this, from scaling and polishing and composite fillings to gum treatment and root canal treatment, is done at Asahii Dental Clinic; the dentist tells you the cause found, the options and the cost before treating, rather than treating several teeth "just in case".

When to have it checked

• Sensitivity that lingers for seconds to minutes after the stimulus, or pain that comes on by itself: possibly pulp inflammation. See What is root canal treatment?.
• Sensitivity in one tooth, especially one with an old filling or a suspected crack.
• Sensitivity with swollen or bleeding gums, or marked recession.
• Visible notches at the gum line, teeth that look shorter, worn biting surfaces.
• No improvement after four to six weeks of using desensitising toothpaste properly.
• Sensitivity after dental treatment that does not settle within a few weeks.

When to see us straight away

• Severe, lingering pain on cold, or pain at night.
• A chipped or broken tooth with sensitivity.
• Swollen gums or a swollen face.

Sensitivity has many causes with different treatments, and only an examination can tell them apart. See our preventive dentistry and general dentistry pages, or book an appointment by hotline 0928 888 121, Zalo or the Mini App.