Why Are My Teeth Suddenly Sensitive?

Here's the thing: the cause is often slow, even when the sensitivity feels sudden.

Under your enamel is dentine, and dentine is full of tiny tubes running to the nerve. Picture a bundle of very tiny drinking straws, all pointing at the nerve. While they're covered, by enamel on top and gum over the root, you feel nothing. Once a patch is exposed, cold, sweet or acidic things make the fluid in the straws move, and the nerve reports it as a sharp zing that's gone in seconds.

Enamel wear and gum recession can creep along for months without a peep. Then one day enough straws are open and the tooth starts complaining. So "sudden" is often the day you noticed, not the day it started. That's my own way of putting it, but it's why I always ask what's changed over the last few months, not just the last few days.

The other possibility is that something new has opened a route to the dentine, like a crack, a patch of decay or a filling that has lost its seal. That's more typical when it's one tooth, which I cover in one tooth suddenly sensitive.

Quite often, yes. The first thing to ask is what's new. The usual suspects:

• A new, firmer toothbrush, or a harder technique. No telling-off here. The people who brush too hard are nearly always the keenest brushers. They just treat their teeth like a burnt pan.
• More acid. A new habit of fizzy water with lemon, fruit juice, sports drinks, or reflux. Acid softens enamel, and brushing straight afterwards wears it faster.
• Whitening. Sensitivity during or after whitening is common and usually settles.
• Stress. A tough few months can mean clenching or grinding, often at night, which wears teeth down.
• Recent dental work. A new filling or crown can be sensitive for a while. See still sensitive to cold weeks after a filling and new crown extremely sensitive to hot or cold.

If you can point to one of these, that's a good start, because it's something you can change. I'd still want to have a look, to make sure that's the whole story.

Very often. When gums shrink back, they uncover the root, and the root has no enamel on it at all. It's the tooth's equivalent of stepping outside in your socks.

Gums recede for a few reasons: brushing too hard, gum disease, and simply getting older, since gums tend to creep back with age. Gum disease is worth ruling out because it often doesn't hurt in the early stages. Bleeding when you brush, puffy gums and teeth that look longer than they used to are all reasons to book in. My hygiene team can help with the cleaning side once I know what's going on.

Usually it's not, but there are a few patterns I take more seriously. Sensitivity from exposed dentine is what's known as a diagnosis of exclusion: I'm only allowed to blame it once I've ruled out the other causes. Clues that it might be something else:

• It's one tooth rather than several, and it came on suddenly.
• It hurts to bite, or there's a sharp pain as you let go. That can point to a crack; see tooth hurts when you release your bite.
• Sweet things set it off in one spot, which can go with decay. More in why does chocolate make my tooth hurt?
• The pain lingers after the cold has gone, throbs, or starts on its own. That suggests the nerve is inflamed, and it won't settle with toothpaste.

And one that isn't your teeth at all. If your teeth ache and you've also got a blocked nose or pain around your cheeks, sinusitis could be behind it. The NHS lists toothache among its symptoms. If the tooth pain doesn't clear up with the cold, get it checked.

For now, the kind basics:

• Switch to a toothpaste made for sensitive teeth. Spit, don't rinse, and rub a little onto the sore spot at night. My guide to stopping sensitive teeth pain fast has the detail.
• Use a soft brush and small gentle circles.
• Cut back on acid, and wait a while after acidic food or drink before you brush.

Then book a check-up, sooner rather than at your next routine visit, if it's severe, it's one tooth, it hurts to bite, you can see a hole or dark spot, or sensitive toothpaste hasn't helped after a few weeks. I'll ask what's changed, look at your gums and enamel, and take an X-ray if I need to. Knowing the cause is what stops it coming back.

Call us today if:

• the pain lingers or throbs after the cold has gone
• it wakes you at night, or painkillers aren't helping
• there's swelling of your gum or face, a bad taste, or a temperature

The NHS advises seeing a dentist if toothache lasts more than two days.

Call 999 or go to A&E, not a dentist, if:

• it's hard to breathe, swallow or speak
• swelling is spreading towards your eye or into your neck
• your eye is swollen or painful, or your eyesight suddenly changes
• you can't open your mouth properly because of swelling

If you're near Harlow or Enfield and your teeth have suddenly turned against you, I'd much rather take a look and find out why than have you avoid cold drinks until spring. Ring your nearest Minti practice to book. If it has turned into proper toothache, say it's urgent and we'll do our best to see you the same day. Anywhere else, or out of hours, call NHS 111.

This article is general information, not a diagnosis. Tooth pain needs examining in person to find the cause.