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Tooth sensitivity — a sharp, brief discomfort triggered by hot, cold, sweet, or acidic foods and drinks — is one of the most common dental complaints among adults. Most people who experience it assume it will pass on its own, or manage it with a supermarket sensitivity toothpaste and say nothing to their dentist. In some cases that's reasonable. In others, sensitivity is an early signal of something that warrants professional attention. This guide explains the main causes of sensitivity, what each typically responds to, and when a clinical assessment is worth seeking. It is for general information only.
Why Teeth Become Sensitive
The sensitivity you feel originates in the dentine — the layer of tooth structure beneath the enamel and below the gumline. Dentine contains thousands of microscopic tubules that connect to the nerve at the tooth's centre. When the enamel or gum tissue that protects the dentine is compromised, temperature changes, pressure, and certain foods can stimulate these tubules and produce the characteristic sharp sensation.
Different causes affect the dentine in different ways, which is why the appropriate response depends on identifying which cause applies.
Enamel Erosion
Acid gradually dissolves tooth enamel, thinning the protective layer over the dentine. The most common sources of dietary acid are fizzy drinks (including sparkling water), citrus fruit and juices, wine, and vinegar-based foods. Acid reflux is a significant cause that many patients don't immediately connect to their dental symptoms.
Signs: Sensitivity that has worsened gradually over time, often more pronounced on front teeth and the biting surfaces of back teeth. You may notice teeth appearing slightly more translucent at the edges.
What typically helps: Reducing frequency of acid exposure, using a straw for acidic drinks, waiting 30–60 minutes before brushing after acid exposure. Prescription-strength fluoride products help to remineralise the surface. Where erosion has progressed significantly, restorative treatment may be needed to rebuild lost structure.
Gum Recession
When the gum pulls away from the tooth, it exposes the root surface — which has no enamel covering and is therefore vulnerable to sensitivity. Recession can be caused by aggressive brushing technique, gum disease, genetics, or a combination of factors.
Signs: Sensitivity concentrated at the gumline, visible lengthening of the tooth, or teeth that feel sensitive to touch as well as temperature.
What typically helps: Switching to a soft-bristled brush and reviewing brushing technique can halt further recession caused by overbrushing. Where gum disease is the cause, treating the disease is the priority. In some cases, gum grafting is available to cover exposed root surfaces — a specialist procedure that also addresses the aesthetic impact of recession.
Cracked or Fractured Teeth
A crack running through a tooth can cause sharp sensitivity that is difficult to reproduce consistently — it may be triggered only at specific angles, or by a particular food. Cracks are often invisible on X-rays and require clinical examination to identify.
Signs: Sharp pain on biting, discomfort that seems to shift, or sensitivity limited to one specific tooth. Cracks caused by grinding (bruxism) often affect multiple teeth simultaneously.
What typically helps: Depending on the depth and location of the crack, a crown may stabilise the tooth. If the crack has reached the pulp, root canal treatment may be needed first. Cracks that extend below the gumline may not be restorable.
Sensitivity From Whitening
Tooth whitening — whether professional or using home products — commonly causes temporary sensitivity during and immediately after treatment. This is a well-documented and usually short-lived effect caused by the whitening agent temporarily increasing permeability of the enamel.
Signs: Sensitivity that began or significantly worsened during or after whitening treatment.
What typically helps: Sensitivity toothpaste used in the weeks before whitening, shorter application times, and taking breaks between whitening sessions typically reduce the effect. The sensitivity almost always resolves within a few days of stopping treatment.
Sensitivity After Dental Work
Sensitivity following fillings, crowns, or other restorative work is common and usually temporary. The tooth has been disturbed, and the nerve takes time to settle. This can last from a few days to a few months depending on the depth of the work and the proximity to the nerve.
What typically helps: It usually resolves on its own. Persistent or worsening sensitivity after dental work — particularly sensitivity to heat rather than cold — should be reported to your dentist, as it can occasionally indicate that the nerve is inflamed and requires further attention.
When to See a Dentist
Sensitivity that is mild, consistent with a known cause (such as whitening), and not worsening is often manageable at home. Sensitivity that warrants a professional assessment includes:
- Sensitivity that is new, or has recently worsened
- Sensitivity limited to a single tooth
- Sensitivity to heat rather than (or as well as) cold
- Sensitivity accompanied by pain that lingers for more than a few seconds
- Visible changes to the tooth's appearance — colour, shape, or length
None of these guarantee a serious cause, but they are worth investigating rather than managing indefinitely with a sensitivity toothpaste that may be masking a signal.
Important Note
This guide is for general information purposes only and does not constitute clinical advice. Sensitivity has many causes, some of which require professional assessment to identify reliably. The information here is not a substitute for examination by a qualified dental professional. Individual circumstances vary — please seek professional advice if you are concerned about your symptoms.