Enamel carries no nerves. For sensitivity to be felt, cold has to reach the dentine beneath it. Dentine is made of microscopic tubules running towards the pulp; fluid inside them moves with temperature change and stimulates nerve endings. Sensitivity is therefore a sign that the inner structure of the tooth has been exposed.
How dentine becomes exposed
- Gum recession: the root surface has no enamel, so it becomes sensitive as soon as it is exposed
- Acid erosion: acidic drinks, reflux and frequent vomiting thin the enamel
- Brushing too hard: wears both enamel and gum
- Grinding: creates micro-cracks along the enamel margins
- Temporary post-procedure sensitivity: may last a few days after a filling, whitening or scaling
Which sensitivity will not settle on its own
Post-procedure sensitivity usually eases within one to two weeks. Sensitivity that steadily worsens, concentrates on a single tooth and lingers for minutes after the cold is removed is a different picture; decay, a crack or pulp inflammation come into consideration. Duration is the most discriminating measure here.
What helps
Desensitising toothpastes containing potassium nitrate or stannous fluoride work by occluding the tubules or reducing nerve conduction, and make a difference within a few weeks of regular use. Reducing how often acidic drinks are consumed, not brushing immediately after them, and wearing a night guard are other effective steps.
Enamel softens temporarily after an acidic drink. Brushing straight away scrapes off that softened layer. Waiting thirty minutes, or first rinsing with water, is more protective.
Frequently asked questions
How long does desensitising toothpaste take to work?
With regular use, a noticeable reduction is usually seen within two to four weeks. The effect fades if use stops, so continued use is advised.
Is whitening sensitivity permanent?
No. Sensitivity after whitening is temporary and usually resolves within a few days. Toothpaste containing potassium nitrate eases this period.
This content is for general information and does not replace an in-person examination. Treatment decisions should only follow a clinical assessment.
Edited by
Papatya Dental
This article draws on the clinical experience of the Papatya Dental team and is reviewed for accuracy before publication.
- Last updated:
- 2026-08-13
- Editorial contact:
- smile@papatyadental.com
