Sensitive Teeth: The Five Real Causes, and What Actually Fixes Them
Sensitive-teeth toothpaste is a painkiller, not a cure. Here are the five actual causes of dentinal hypersensitivity, how a dentist identifies which one is yours, and why the right treatment varies from a fluoride varnish to a bonded filling.
In short
When gums recede, the root surface (which has no enamel) is exposed. Dentine contains microscopic tubules that connect to the nerve. Cold air, cold water, or sweet food flows through these tubules and hits the nerve. Treatment depends on severity: mild cases respond to prescription-strength fluoride varnish applied every 3 months; moderate cases need bonded composite "coverage" of the exposed root; severe cases may need a gum graft to restore the missing gum. Stop using hard-bristled brushes — they cause 40% of recession cases.
Gum recession — exposure of dentine tubules
When gums recede, the root surface (which has no enamel) is exposed. Dentine contains microscopic tubules that connect to the nerve. Cold air, cold water, or sweet food flows through these tubules and hits the nerve. Treatment depends on severity: mild cases respond to prescription-strength fluoride varnish applied every 3 months; moderate cases need bonded composite "coverage" of the exposed root; severe cases may need a gum graft to restore the missing gum. Stop using hard-bristled brushes — they cause 40% of recession cases.
Acid erosion — softened enamel
Frequent exposure to acidic drinks (karak with lemon, soft drinks, sparkling water, fresh juices, and especially citrus) dissolves enamel over time. The surface beneath is softer dentine, which transmits cold and sweet signals. Reflux (GERD) does the same thing from the inside. The fix is prevention: rinse with water after anything acidic, wait 30 minutes before brushing so the softened enamel has time to remineralise, and use a high-fluoride toothpaste. Severe cases need composite or zirconia restorations of the worn surfaces.
Cracked tooth — the sharp, specific pain
A cracked tooth produces a distinctive pain: sharp on biting something hard, then a lingering ache for a second after release. If you can point to one specific tooth and it only hurts on biting, suspect a crack. Cracks are invisible on X-ray; diagnosis needs a bite stick test and sometimes a dye. Treatment is a crown to hold the tooth together before the crack progresses into the root — at which point extraction becomes the only option.
Night grinding (bruxism) — micro-flexure of teeth
Grinding teeth at night flexes them under enormous force. The flexure creates tiny notches at the gum line (abfraction lesions) and microfractures in the enamel, both of which cause generalised sensitivity. The fix is a proper occlusal nightguard made from an impression (not a boil-and-bite from the pharmacy, which can make things worse). OMR 80–150 and it typically pays for itself in prevented damage within 12 months. Morning headaches and a sore jaw are the other tells.
Post-whitening sensitivity — transient, avoidable
Carbamide or hydrogen peroxide whitening temporarily opens the dentine tubules. 40–60% of patients experience mild sensitivity during treatment and for 48 hours after. It resolves on its own but is uncomfortable. Prevention: use a desensitising toothpaste (potassium nitrate based) for two weeks before whitening, space the treatment over longer days, and avoid same-day cold drinks. Severe persistent sensitivity after a whitening course means the peroxide concentration was too aggressive — discuss with your dentist before continuing.
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