What causes tooth sensitivity?
The main cause of tooth sensitivity is exposed dentin, the inner layer of the tooth, which contains microscopic tubules leading to the nerve.
When enamel wears away or gums recede, the dentin is exposed and stimuli travel through the tubules to the nerve, which is why the feeling is so sharp. Dentin is exposed by gum recession, chemical wear (erosion) of the enamel from frequent acidic foods and drinks, and mechanical wear from poor brushing technique or bruxism (unconscious grinding, mostly at night). According to the ADA, decay, a broken tooth, worn fillings and gum disease can also cause sensitivity.
Direct damage such as holes in teeth or a cracked tooth is another important risk factor. When the tooth is damaged, the path to the nerve opens and an external trigger becomes immediate pain. Old or cracked fillings can also leave the tooth exposed. Sometimes the wear comes from brushing too hard with a hard toothbrush, a cause that is easy to fix but often overlooked.
Sensitive teeth in pregnancy
Hormonal changes in pregnancy affect oral health and can increase sensitivity in the gums and teeth. Higher progesterone and estrogen levels change blood flow to the gums, making them swollen and more sensitive. This is called pregnancy gingivitis; according to the CDC, 60% to 75% of pregnant women have gingivitis. Nausea and sensitivity to tastes lead many women to brush less, and frequent vomiting in the first trimester exposes enamel to stomach acid, speeding up erosion and sensitivity.
Many women also eat small, frequent meals during pregnancy, which keeps the mouth acidic and makes it harder for saliva to protect the teeth. Keep up careful oral hygiene and ask your dentist about suitable care (see dental care during pregnancy).
Sensitivity after a dental cleaning
Sensitivity after a dental cleaning is common and leads some patients to avoid hygiene visits. It happens mainly because the tartar that covered the neck of the tooth, and insulated exposed dentin, has been removed, and because the gums were irritated during the cleaning. The exposed dentin then reacts to stimuli, especially temperature. This is an expected reaction that usually fades within a few days to two weeks.
When a lot of tartar was removed or a deep cleaning was done below the gums, sensitivity can last longer. Use a toothpaste for sensitive teeth in the following days, avoid very hot or very cold food and drinks, and keep brushing gently and thoroughly. Temporary sensitivity is no reason to skip regular cleanings: avoiding them can worsen the condition of the gums and teeth and lead to problems such as rotten teeth.
Sensitivity after a filling
Sensitivity after a filling is common and usually temporary.
Why it happens
Sensitivity comes from irritation of the nerve while the cavity is prepared, from the acid used to bond the filling, and from pressure while the cavity is filled. When the decay was deep and close to the nerve, the remaining dentin is thin and the nerve more reactive. Modern bonding requires etching the surface with phosphoric acid, which can cause temporary sensitivity, and composite shrinks slightly as it hardens under the light, which can create stress in the tooth.
Beyond two weeks
In most cases sensitivity decreases gradually over a few days, as the nerve settles and the tooth builds an extra layer of dentin. If it lasts more than two weeks or gets worse, go back for a check-up. Sometimes the filling is slightly too high and touches first when you close; a simple adjustment usually solves it.
Severe pain or pain at night
When sensitivity comes with severe pain or a toothache at night, the nerve may be inflamed and need further treatment, sometimes a root canal. In that case, ask for an urgent appointment with an emergency dentist.
Sensitivity after teeth whitening
Teeth whitening often causes temporary sensitivity, because the whitening agent passes through the enamel and dentin. Whitening products release active oxygen from hydrogen peroxide or carbamide peroxide, which breaks down stain molecules inside the tooth; this temporarily dehydrates the tooth and irritates the nerve through the tubules. According to a Cochrane review, the side effects of home whitening are mild and temporary, and more frequent at higher concentrations.
Sensitivity after whitening can be reduced with fluoride beforehand, desensitizing gels and suitable aftercare. Temporary, mild to moderate sensitivity is common at the start of treatment: according to the ADA, it affects up to about two-thirds of patients. If you already have tooth sensitivity before whitening, your dentist can recommend a desensitizing toothpaste beforehand. Whitening only lightens natural teeth, not crowns, veneers or fillings.
Cold sensitivity: why teeth hurt with cold
Sensitivity to cold is the most common symptom of exposed dentin, and often the first sign of a problem with the tooth structure or the gums. The sharp reaction to a cold drink, cold air or food from the fridge comes from rapid movement of fluid inside the dentinal tubules, which stimulates the nerve fibers. This hydrodynamic mechanism explains why extreme temperatures cause a stronger reaction.
Cold sensitivity after porcelain veneers is related to bonding: preparing the tooth removes a thin layer of enamel and sometimes exposes dentin, and bonding involves etching with phosphoric acid, which opens the tubules temporarily.
Sensitivity can be noticeable while temporary veneers are in place. Even after final bonding, an adjustment period of a few weeks is normal; only if sensitivity persists should the seal or fit of the veneer be re-evaluated.
No reaction to cold can be more worrying than sensitivity: when a tooth that used to be sensitive stops responding to a cold test (cold spray or ice), its nerve may have died (necrosis). Diagnosis continues with an X-ray and sometimes an electric pulp test, and if necrosis is confirmed, a root canal is usually needed to prevent an abscess or an infection spreading to the jaw bone. This is especially common after trauma, deep decay or a chronic infection that developed gradually without clear symptoms.
What triggers the pain also helps point to the cause:
| When the tooth hurts | Possible cause | When to see a dentist |
|---|---|---|
| With cold, a sharp pain that fades within seconds | Exposed dentin: gum recession, enamel wear, after a cleaning or a filling | If the sensitivity does not ease with a toothpaste for sensitive teeth |
| With heat, or pain that lingers after the trigger is gone | Inflamed nerve, for example from deep decay or a crack | Soon; severe pain or pain at night calls for an urgent visit |
| With sweets | Decay, a worn filling or exposed dentin | At an early check-up |
| When chewing or biting | A cracked tooth, a filling that is too high, or decay | Soon, before a crack spreads |
Examination, treatment plan and price quote
detailed and personalized
During the consultation, Dr Haim Aseriel examines your teeth, explains all the options and gives you a transparent price quote, with no obligation. The clinic is at 12 HaTnufa Street, Jerusalem.
How is tooth sensitivity treated?
Treatment for sensitive teeth is step by step and adapted to the severity and the cause. The first line is a desensitizing toothpaste containing potassium nitrate or stannous fluoride, which reduces the transmission of stimuli to the nerve. Potassium nitrate calms the nerve fibers, while stannous fluoride forms deposits that narrow the openings of the tubules. Results are not immediate: according to the ADA, it usually takes several uses before sensitivity decreases. A soft toothbrush and gentle brushing, without hard horizontal strokes, also prevent further damage to enamel and gums.
When home care is not enough, in-office treatments can help: a high-concentration fluoride gel or varnish applied to sensitive areas forms a protective layer, and bonding agents applied to exposed surfaces, especially at the neck of the tooth, also help. With significant recession and widely exposed roots, a gum graft may be needed to cover them. According to the ADA, a crown, an inlay or bonding is sometimes appropriate and, for severe, persistent sensitivity, a root canal.
60min
wait after acidic food before brushing (ADA)
Treatment does not end in the dental chair: daily habits matter too.
Cutting down on acidic foods and drinks (sodas, wine, fruit juices, pickles), waiting about an hour after something acidic before brushing (according to the ADA, this lets saliva neutralize the acid and re-harden the enamel), and chewing sugar-free gum to boost saliva all help. For people who grind their teeth, a night guard protects against further wear.
What is Gluma, and how does it help sensitive teeth?
Gluma is a desensitizing agent containing glutaraldehyde and HEMA that seals the tubules in the dentin. The dentist applies it in the office to exposed dentin, for example at the neck of the tooth or on a root exposed by gum recession. It belongs to a broad group of desensitizing treatments that block the tubules physically or chemically; others contain, for example, potassium oxalate, arginine or fluoride compounds. Sealing the tubules reduces the transmission of stimuli to the nerve, and more than one application is sometimes needed.
Nano-hydroxyapatite
Newer products are based on nano-hydroxyapatite, the mineral that makes up enamel and dentin, designed to integrate into the tooth structure and close the openings of the tubules.
Laser
Different types of laser (for example erbium or diode) are also used to treat dentin hypersensitivity: controlled thermal energy modifies the dentin surface and helps close the tubules. The clinic does not use lasers: sensitivity is treated there with desensitizing agents, fluoride and bonding agents.
The clinic is at 12 HaTnufa Street in Talpiot, south Jerusalem, open Sun 8:00–19:00 · Mon 9:00–19:00 · Tue–Wed 9:00–21:00 · Thu 8:30–21:00 · Fri 8:00–14:00. The cause of your sensitivity is examined and the options explained in English, with a written quote when treatment is needed.
Tooth sensitivity: frequently asked questions
The first-line treatment for sensitivity is a toothpaste for sensitive teeth containing potassium nitrate or stannous fluoride, used regularly with gentle brushing and a soft toothbrush. If the sensitivity does not ease, your dentist can apply a desensitizing agent in the office, such as a fluoride varnish or Gluma.
Sensitivity after a dental cleaning is an expected reaction that usually fades within a few days to two weeks. When a lot of tartar was removed or a deep cleaning was done below the gums, it may last longer. A toothpaste for sensitive teeth and gentle brushing help during this period.
Sensitivity after a filling usually decreases gradually over a few days. If it lasts more than two weeks, gets worse, or comes with severe pain or pain at night, go back to the dentist: the filling may be too high or the nerve may be inflamed.
Sensitivity after teeth whitening is temporary, mild to moderate, and common at the start of treatment: according to the American Dental Association (ADA), it affects up to about two-thirds of patients. People who already have sensitive teeth before whitening should ask their dentist about suitable preparation.
A tooth that used to be sensitive and stops reacting to cold may have a dead nerve (necrosis). It needs a dental examination with vitality tests and an X-ray; if necrosis is confirmed, a root canal is usually needed to prevent an abscess and infection of the jaw bone.
Sources
- American Dental Association (MouthHealthy), Sensitive Teeth – View the page
- Favaro Zeola L et al., Journal of Dentistry, 2019 – View the study
- Forouzande M et al., Gluma and dentin hypersensitivity, 2022 – View the study
- American Dental Association, Whitening (Oral Health Topics), 2022 – View the page
- Eachempati P et al., Cochrane Database of Systematic Reviews, 2018 – View the study
- Centers for Disease Control and Prevention, Talking to Pregnant Women about Oral Health – View the page
- American Dental Association (MouthHealthy), Dietary Acids and Your Teeth – View the page
