A short, sharp pain from a sip of cold water is the classic description of sensitivity. The cause is thinning of the protective outer layer, exposing the dentine beneath. Dentine contains microscopic tubules leading to the nerve; temperature change moves fluid in them and produces pain.
Most common causes
1. Aggressive brushing and gum recession
Horizontal, forceful brushing notches the tooth neck and pushes the gum back. Root surface is not covered by enamel, so it is directly sensitive.
2. Acid erosion
Fizzy drinks, citrus, vinegar and reflux dissolve enamel. In reflux patients, sensitivity often starts on the inner surfaces of back teeth.
3. Grinding
Excessive force fatigues enamel, flattening chewing surfaces and causing cracks.
4. Decay or fracture
Sensitivity concentrated in one tooth and increasing usually signals decay or a crack.
5. Temporary post-procedure sensitivity
A few days of sensitivity after whitening, scaling or a new filling is normal.
What helps at home
- Use desensitising toothpaste; effects appear in 2–4 weeks. Rubbing a small amount onto the area and not rinsing increases the effect.
- Switch to a soft brush and reduce pressure.
- Wait 30 minutes before brushing after acidic food.
- Ask about a night guard if you grind.
When to see a dentist
If sensitivity is concentrated in one tooth, starts spontaneously, wakes you at night, or lasts more than 30 seconds after the stimulus is removed, it is no longer simple sensitivity and requires examination.