Tooth sensitivity happens when the dentine beneath the enamel becomes exposed, usually through gum recession, enamel erosion or aggressive brushing. Microscopic tubules in dentine transmit temperature changes to the nerve, producing a sharp, brief pain. Desensitising toothpaste used correctly helps most cases within two to four weeks. Pain that lingers after the stimulus is removed suggests pulp inflammation, not sensitivity, and needs assessment.
The distinction that matters most
Genuine dentine sensitivity is sharp and stops within a second or two of removing whatever triggered it. That is uncomfortable but not dangerous.
Pain that lingers for thirty seconds or more, that throbs, that wakes you at night or that worsens when you lie down, is a different problem — inflammation of the pulp inside the tooth. That does not resolve with special toothpaste and usually needs root canal treatment. If your symptoms match this description, book an appointment rather than buying another tube.
What exposes the dentine
- Gum recession from gum disease or over-vigorous brushing, exposing the root surface which has no enamel at all.
- Acid erosion from citrus, fizzy drinks, or acid reflux dissolving enamel.
- Brushing hard with a stiff brush, wearing a notch at the gum line.
- Grinding and clenching, wearing through enamel on the biting surfaces.
- Recently after a filling, scaling or whitening — usually temporary.
- A cracked tooth, which typically hurts on releasing a bite rather than on cold.
What actually helps
- Use desensitising toothpaste properlyMost people use it wrongly. Do not rinse it off. Brush, spit out the excess and leave the residue. Better still, rub a smear onto the sensitive area with a fingertip at bedtime and leave it overnight. Give it two to four weeks.
- Switch to a soft brush and lighten upHold the brush in your fingertips rather than your fist. Pressure does not clean better; it only wears enamel and gum.
- Address the acidReduce fizzy drinks and citrus, use a straw for acidic drinks, and if you have reflux, get it treated — nocturnal reflux erodes teeth remarkably fast.
- Get grinding assessedIf you wake with jaw ache or have flattened teeth, a night guard protects what enamel remains.
- Have the cause treatedFluoride varnish, bonding over an exposed root notch, or gum treatment where recession is the cause. Sensitivity is a symptom; something is producing it.
When it is not sensitivity at all
Book an appointment rather than self-treating if the pain lingers after the trigger is gone, if it wakes you at night, if there is swelling, if a specific tooth hurts when you bite down or release, or if it has been getting steadily worse despite desensitising toothpaste. Each of those points to a cause that toothpaste cannot reach.
Questions we get asked
How long does desensitising toothpaste take to work?
Two to four weeks of consistent twice-daily use. Most people give up at one week and conclude it does not work. Leaving the residue on rather than rinsing makes a substantial difference.
Can gum recession grow back?
Not on its own. Where it is severe and causing significant sensitivity or aesthetic concern, a gum graft can cover the exposed root. Most cases are managed by stopping the cause and treating the sensitivity.
Is sensitivity after a filling normal?
Mild sensitivity for a few weeks after a deep filling is common as the pulp settles. If it worsens, lingers, or the tooth becomes painful to bite on, have it checked — the filling may be high or the pulp may be inflamed.