Guides · General
Tooth sensitivity: why teeth twinge in the cold, and what helps
The causes of the short, sharp twinge from cold, heat and sweets; what you can do at home, how desensitising toothpastes work and the situations that need an examination.
Tooth sensitivity is the reaction of dentinal tubules exposed by enamel wear or gum recession to cold, heat, sweets and touch; it shows as a short, sharp twinge. A desensitising toothpaste (used regularly for 2–4 weeks), a soft brush, fewer acidic drinks and fluoride or bonding agents applied in the clinic are enough in most cases. Pain that starts on its own, lasts minutes or throbs is a sign of decay or pulp inflammation.
The dentine beneath the enamel is connected to the tooth's nerve by tiny tubules. When enamel wears away or the gum recedes and exposes the root surface, these tubules are opened to the outside; cold, heat, sweetness and touch reach the nerve and cause a brief, sharp twinge.
Causes
- Gum recession: The root surface has no enamel; hard brushing or gum disease leads to recession.
- Enamel wear: Acidic drinks, reflux, frequent vomiting, clenching and a hard brush.
- Decay and fractures: Decay and cracks reaching the dentine.
- A new filling or crown: Temporary sensitivity for a few weeks after treatment is normal.
- Whitening: Temporary, during treatment and for a few days after.
- After scaling: Surfaces previously covered by calculus are exposed; eases in 1–2 weeks.
What you can do at home
- Desensitising toothpaste: Those containing potassium nitrate or stannous fluoride block the tubules or calm the nerve; the effect appears after 2–4 weeks of regular use. Rubbing the paste onto the sensitive spot with a finger and leaving it increases the effect.
- Soft brush, light pressure: Horizontal, hard brushing cuts notches at the gum line. A pressure sensor on an electric brush helps.
- Don't brush straight after acidic drinks: Acid softens enamel; wait 30 minutes and rinse with water meanwhile.
- A night guard if you clench.
What is done in the clinic
Fluoride varnish or desensitising agents are applied to exposed root surfaces; marked notches are filled with composite; a gum graft is considered if recession is extensive. In sensitivity caused by decay or a crack, the underlying cause is treated.
When to have an examination
- If the twinge lasts more than 30 seconds after the stimulus or starts on its own (possible pulp inflammation)
- If there is pain on biting in a single tooth (possible crack)
- If gum recession is progressing
- If there is no improvement within 4 weeks despite desensitising toothpaste
Sensitivity, decay or a crack?
| Symptom | Likely cause |
|---|---|
| Short, sharp twinge with cold; gone when the stimulus goes | Dentine hypersensitivity (recession, wear) |
| Twinge with sweets, in one particular tooth | Decay |
| Sudden sharp pain on biting, and a twinge on release | Cracked-tooth syndrome |
| Pain worsened by heat, lasting minutes, throbbing at night | Pulpitis — root canal treatment may be needed |
| Biting sensitivity after a new filling | High bite — a short adjustment |
Hidden causes of enamel erosion
- Reflux: Stomach acid erodes especially the inner surfaces of the back teeth; managed together with a gastroenterologist.
- Frequent acidic drinks: Fizzy drinks, energy drinks, lemon water, fruit juice — including "healthy-looking" apple-cider-vinegar and lemon regimes.
- Eating disorders and frequent vomiting.
- Whitening/abrasive toothpastes, charcoal and bicarbonate.
- Clenching: Notches at the neck of the tooth.
How to use desensitising toothpastes
Potassium-nitrate pastes reduce nerve excitability (effect in 2–4 weeks); those with stannous fluoride and arginine block the tubules (faster). Effective use: twice a day, spit without rinsing after brushing; rub onto the sensitive area with a finger and leave for a minute. The effect lasts as long as use continues; sensitivity may return within weeks of stopping.
Lasting solutions in the clinic
- Fluoride varnish / desensitising agent: Repeated every 3–6 months
- Bonding agent: Seals exposed dentine; a few minutes
- Composite filling: For marked cervical notches
- Gum graft: Covers the root surface if recession has progressed
- Night guard: For notches and sensitivity due to clenching
- Laser treatment: Sealing the tubules in selected cases
Sensitivity after scaling and whitening
Temporary sensitivity after both procedures is normal and eases in 1–2 weeks. Using a desensitising toothpaste for 2 weeks before whitening reduces the side effect markedly. More: Gum recession · Is scaling harmful?
This article is for general information only; diagnosis and treatment tailored to you require a dental examination.
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