That twinge with cold drinks.

Tooth sensitivity is the most widely recognised dental symptom there is: the short, sharp twinge with a cold drink, a sweet bite or a breath of winter air. It is common, it is usually simple, and managing it well starts with knowing why it is happening.

Why teeth feel it

Under the enamel is dentine, a softer layer threaded with tiny channels that run to the nerve. Enamel insulates it. Where dentine is exposed: by worn enamel or by gums that have receded from the root, which has no enamel at all: cold, sweet and even air reach the nerve directly, and the tooth feels it.

The usual causes

Brushing too hard, or with a stiff brush, which wears enamel and pushes gums back; gum recession from gum disease or from years of hard brushing; acidic drinks, colas, citrus, sports drinks, wine, dissolving enamel a little at a time; grinding or clenching, which wears the biting surfaces; a chipped or cracked tooth; and recent whitening, where sensitivity is expected and temporary.

Three things that help

A soft brush and a lighter hand: the bristles should barely bend. A toothpaste for sensitive teeth, used every day as your only toothpaste rather than just when it hurts; it takes two to four weeks to work, and stops working when you stop. And fewer acidic drinks, with a straw when you do have one, and water afterwards rather than brushing straight away, because enamel is softer for half an hour after acid.

When to have it looked at

If the sensitivity is new, if it lingers after the cold has gone rather than fading in seconds, or if it is one tooth in particular rather than a general twinge, an assessment finds the cause. Often a small filling over an exposed patch, a fluoride varnish, or some gum care is all that is needed. Sensitivity that lingers for a minute or more is a different pattern, the toothache explainer describes it, and worth describing when you call.

A check-up is where the cause is found. Where receded gums are the reason, the gum treatment page explains what can be stabilised.