Sensitive teeth: why cold hurts and how to fix it

In short: sensitivity to cold appears when the inner layer of the tooth (the dentine) becomes exposed, usually due to brushing too hard, gums that recede or worn enamel. The good news is that in most cases it can be solved. Here we tell you why it happens and what you can do.

Why does my tooth hurt when I have something cold?

Your tooth has three layers. On the outside, the enamel, which is extremely hard and has no nerves. Beneath it, the dentine, which is full of micro-channels that connect to the tooth’s nerve. And in the centre, the pulp, where that nerve is.

While the enamel and gum cover the dentine well, you feel nothing. The problem comes when that dentine becomes exposed: cold (or sweet things, or the air on a winter’s day in Bilbao) enters through those channels and the nerve warns you with a short, sharp twinge. It is not a deep, continuous pain, it is more of an “ouch!” that passes quickly.

What makes the dentine become exposed?

The most common causes we see at the clinic are these:

• Brushing too hard. Many people think that pressing harder cleans more, and it is exactly the opposite: it wears down the enamel and pushes the gum down. A hard-bristled brush does the same.
• Receding gums. When the gum goes down, it exposes the root of the tooth, which has no enamel and is much more sensitive. This can come from aggressive brushing or from gum disease.
• Enamel wear. The rubbing of the teeth (especially if you clench or grind at night) and very acidic foods gradually thin the enamel.
• Decay or leaking fillings. Decay that is starting or an old filling that no longer seals well also cause sensitivity.

What can I do at home so it does not hurt?

There are simple things that help from day one:

• Change your brushing technique. A soft brush, movements without pressure and no “sawing”. Force does not clean; what cleans is technique.
• Use a toothpaste for sensitive teeth. It calms the tooth’s endings, but you have to use it daily and give it a few weeks. A tip: after brushing, leave a little toothpaste on the sensitive area without rinsing hard.
• Be careful with acidic things. Fizzy drinks, citrus and vinegar soften the enamel. And an important tip: do not brush right after having something acidic, wait a while.
• If you clench at night, mention it at your check-up. Sometimes a night guard changes everything.

When do I need to go to the dentist?

Here is the important part: toothpaste for sensitive teeth covers the symptom, but does not fix the cause. It is worth getting checked if:

• The pain lasts more than two or three weeks.
• You notice it getting worse or it already hurts with heat too.
• The twinge appears in one specific tooth and always the same one.
• You can see the gum receding or the tooth “longer” than before.

At the clinic we look for the why. Sensitivity is often linked to gum health, and that is where periodontics comes in. Other times the origin is decay that has reached the nerve, and then we are talking about root canal treatment. And a good regular dental cleaning helps keep the gums healthy and slow down recession.

Can sensitivity be prevented?

To a large extent, yes. Gentle brushing, regular check-ups to catch things in time and looking after your gums are the best defence. Sensitivity almost never appears out of nowhere: it is usually the warning of something that can be corrected if caught early.

This guide is for information only and does not replace a consultation or a professional diagnosis. Every mouth is different and it is worth assessing your case in person.

If you have had that discomfort with cold for a while and want to know what is causing it in your case, write to us with no obligation from our contact page and we will take a calm look.