A mouthful of cold water, a spoonful of ice cream, or just breathing in on a winter morning, and a short sharp pain runs through the tooth and passes in a few seconds. That is tooth sensitivity, one of the commonest complaints people come in with, and it almost always has a cause that can be named.
Where sensitivity comes from
Beneath the enamel is dentine, a tissue threaded with tiny channels leading towards the nerve of the tooth. While the dentine is covered by enamel or gum, those channels are closed. Once that cover thins or recedes, what is outside reaches the nerve, and you feel it as a short pain.
- Receding gums: they expose the neck of the tooth, where there is least enamel.
- Brushing too hard, or with a hard brush: it wears enamel and pushes the gums back.
- Acid in the diet: lemon, juices, fizzy drinks and wine soften enamel.
- Grinding your teeth: enamel wears on the biting surfaces.
- A cracked tooth or a failing filling: the pain is then tied to one particular tooth.
- After whitening or scale removal: passing sensitivity, usually a few days.
What separates sensitivity from something that will not wait
Sensitivity is brief: the stimulus goes, the pain goes. If the pain lasts after you have taken the cold away, if it throbs, wakes you at night or arrives on its own, that is no longer sensitivity but a sign the pulp is involved. We have written about that in the article on throbbing toothache, and it is a reason to come in without delay.
Pain when biting on one particular tooth is also not ordinary sensitivity; it is often a sign of a crack or a filling that has failed.
What you can do yourself
- A soft brush and brushing without pressure; a brush cleans by movement, not by force.
- Toothpaste for sensitive teeth, every day, for at least a few weeks; the effect builds and does not arrive after one brushing.
- Rub a little of that paste onto the sensitive spot with a finger in the evening and do not rinse.
- Acidic things with a meal rather than between meals, and no brushing for half an hour afterwards.
- A straw for acidic and fizzy drinks.
If there is no difference after a few weeks, the cause is not hygiene and an examination is the next step.
What we do at the examination
First we look for the cause: where the gums have receded, whether there is decay, a crack or a leaking filling, and what the bite is like. An X-ray is taken if needed. Only then is the treatment chosen.
Where the necks of the teeth are exposed, varnishes that seal the channels help; where more tissue has been lost, a filling that covers the exposed part. Where the cause is decay or a failing filling, it is dealt with through restorative dentistry. Where the cause is inflamed and receding gums, through periodontics. Where the cause is grinding, a splint is made, which we have written about in the article on bruxism.
What does not help, and often gets tried
Brushing harder and using a stiffer brush make matters worse: pressure is one of the causes of receding gums and worn enamel in the first place. The same goes for pastes with a coarse abrasive that promise whitening by scrubbing — they remove deposits, and some of what protects the tooth with them.
Rinsing with strong solutions, and home recipes with bicarbonate of soda or lemon, do not address the cause either. Bicarbonate is an abrasive and lemon is an acid; both feel refreshing in the short term and thin the very layer that is making the tooth sensitive in the long one.
Avoiding hot and cold is not treatment but getting used to the problem. If you have stopped drinking cold water or chew on one side only, that is worth mentioning at the examination — a change of habit like that usually means the cause has been there longer than it seems.
Sensitivity after treatment
Mild sensitivity to cold for a few days after a deep filling, scale removal or whitening is not unusual and settles by itself. If it grows instead of easing, or lasts more than a week, tell us — that is information, not something to put up with.
- Why does a tooth twinge on cold when I have no cavity?
- Usually because the neck of the tooth is exposed, where there is least enamel. Decay is not the only cause of sensitivity.
- Does toothpaste for sensitive teeth help?
- For most people it does, but not immediately: the effect builds with daily use over several weeks. If there is no difference after that, the cause should be looked for at an examination.
- Does whitening make teeth sensitive for good?
- Sensitivity after whitening is usually passing and settles within a few days. If it does not, tell us.
- Should I stop brushing the sensitive spot?
- No. An unbrushed spot collects deposits, the gums become more inflamed and the sensitivity grows. Brush gently, with a soft brush, but every day.
- When is sensitivity more than sensitivity?
- When the pain lasts after the stimulus has gone, when it throbs, wakes you at night or arrives on its own. That is a reason to come in without delay.