Why Are My Teeth Sensitive? Common Causes and Gentle Next Steps

You take a sip of iced water or a spoonful of ice cream and a sharp, brief pain shoots through a tooth. It fades in seconds, but it is enough to make you chew on the other side for the rest of the day. Tooth sensitivity is very common, and while it is often manageable, it is your mouth telling you something has changed.

What is happening inside the tooth

The outer layer of a tooth, the enamel, is hard and protective. Below the gumline, the root is covered by a softer layer instead. Underneath both sits dentine, which contains many tiny channels leading towards the nerve. When enamel wears thin or gums pull back to expose the root, those channels are left more open. Cold, heat, sweetness or even a breath of winter air can then travel through them and trigger that quick, sharp pain.

Common causes

Brushing too hard

Scrubbing with a hard brush or a sawing motion can wear enamel and push gums back over time. Gentle, small circles with a soft brush clean just as well.

Acidic food and drink

Fizzy drinks, citrus fruit, fruit juices, wine and sports drinks can soften the enamel surface. Frequent sipping through the day keeps teeth in that softened state for longer.

Gum recession

Gums can draw back with age, gum disease or rough brushing, exposing the root surface, which is far more sensitive than the crown.

Grinding and clenching

Many people grind their teeth during sleep or clench during stressful days without realising. This can wear enamel and cause small cracks.

Decay, cracks and worn fillings

A cavity, a chipped tooth or an old filling that has started to leak can all expose sensitive layers. Pain from these causes often lingers longer or focuses on one tooth.

After dental treatment

Short-term sensitivity after a filling, a scale and polish or whitening is common and usually settles. If it does not, mention it to your dentist.

Everyday habits that can help

• Switch to a soft brush and let it do the work, without pressing hard.
• Try a toothpaste made for sensitive teeth. Many people find it helps when used every day for a few weeks. Ask a pharmacist or dentist which type suits you.
• Spit, do not rinse, after brushing, so the fluoride stays on the teeth for longer.
• Keep acidic drinks to mealtimes rather than sipping them throughout the day, and consider a straw for cold or fizzy drinks.
• Wait a little before brushing after something acidic, rinsing with water in the meantime.
• Notice clenching during stressful work and let your jaw relax, lips together and teeth apart.

A dry mouth can also leave teeth more vulnerable, since saliva helps protect the enamel. Our article on what causes dry mouth explains why.

What a dentist may do

A dentist will look for the cause before treating the symptom. Depending on what they find, they might apply a protective varnish or coating, recommend a particular toothpaste, repair a cavity or worn filling, suggest a night guard if grinding is the problem, or treat gum disease. Where gums have receded a long way, other treatments may be discussed. If teeth are missing or badly damaged, replacements such as those described in our piece on modern dental implants may eventually come up, though that is a separate conversation.

When to book an appointment

Mild, occasional twinges that ease with a gentler routine are common. Arrange to see a dentist if:

• Sensitivity has lasted more than a few weeks despite changing your habits.
• Pain lingers long after the hot or cold food has gone.
• One tooth hurts more than the rest, or hurts when you bite.
• You notice a crack, a hole, a dark patch or a lost filling.
• Your gums bleed, look swollen or seem to be shrinking.

Seek prompt help if you have swelling in the face or jaw, a fever, or a throbbing pain that keeps you awake, as these can point to an infection that needs treatment soon.

The short version

Sensitive teeth usually come from worn enamel or exposed roots, and both often build slowly from everyday habits. Gentle brushing, less frequent acid and a toothpaste made for the purpose help many people. A dentist can find the cause, which is the most reliable way to stop the twinge from coming back.