Tooth Sensitivity: Causes, Remedies & Treatment
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Tooth sensitivity is a common dental problem that involves discomfort or pain in teeth when encountering certain substances and temperatures. At least 40 million adults suffer from sensitive teeth in the United States, according to the Academy of General Dentistry. 

The pain is often sharp and sudden, but it is temporary. According to the Cleveland Clinic, the pain may shoot into the tooth's nerve endings. Fortunately, sensitive teeth can be treated and the condition can improve. 

There are no at-risk groups for tooth sensitivity. It can happen to anyone, according to Dr. Margaret Culotta-Norton, a dentist in Washington, D.C., and former president of the D.C. Dental Society.

"The most common symptom … is a sudden, sharp flash of pain when teeth are exposed to air, cold, sweet, acidic or hot foods," she told Live Science. Some people may experience tooth sensitivity from brushing or flossing their teeth.

In healthy teeth, enamel protects the underlying layer of dentin, which is softer than enamel. The tooth roots are protected by gums. But if the enamel is worn down or if the gum line has receded, then the dentin becomes exposed. "Cavities, cracked teeth, gum recession, enamel and root erosion all cause dentin to be exposed," Culotta-Norton said. "Dentin is connected to the nerve that triggers pain in sensitive teeth."

Dentin contains thousands of microscopic tubules, or channels, leading to the tooth's pulp, according to the Academy of General Dentistry. When exposed to the elements, these dentinal tubules allow heat, cold, acidic or even sticky substances to reach the nerves inside the tooth, causing pain.

According to the Cleveland Clinic, some factors that contribute to sensitive teeth may include:

  • Brushing too hard or using a hard-bristled toothbrush. This can wear down enamel, causing dentin to become exposed, or encourage gum recession.
  • Gum recession. This often happens in people suffering from periodontal disease, and it exposes the dentin.
  • Gingivitis. Inflamed and sore gum tissue can result in exposure of the tooth's root.
  • Cracked teeth. These can become filled with bacteria from plaque and cause inflammation in the pulp of the tooth. In more severe cases, it may lead to abscess and infection.
  • Teeth grinding or clenching. This can wear down enamel.
  • Plaque buildup.
  • Long-term use of mouthwash. Some over-the-counter mouthwashes contain acids. If dentin is exposed dentin, the acids can make existing tooth sensitivity worse and also further damage the dentin layer. There are neutral fluoride mouthwashes available that might be a better option.
  • Acidic foods. These can encourage enamel reduction.
  • Dental procedures. Teeth may be sensitive after professional cleaning, root planing, crown replacement and other tooth restoration procedures. Usually the pain will disappear in four to six weeks.

Some people may experience tooth sensitivity after having a cavity filled or a filling replaced, according to the Columbia University College of Dental Medicine. The tooth decay that causes cavities irritates the tooth, and the filling procedure, while necessary, can lead to further sensitivity. Fortunately, tooth sensitivity after a filling should improve on its own within a few weeks. It may last longer, as much as a few months, but as long as the tooth sensitivity shows gradual improvement, there should be nothing to worry about. Persistent tooth sensitivity, however, may indicate that a root canal is needed.

Sometimes after a filling, teeth become sensitive when biting down. This can be fixed with a simple bite adjustment. Additionally, the filling may be too high, according to Columbia University. In this case, the dentist could lower the filling.

Composite fillings may cause tooth sensitivity when chewing. There is no pain when the teeth are clenched together, however. This tooth sensitivity is usually fixed by adjusting the bite or replacing the filling with another composite, according to Bear Peak Dental, a private practice in Boulder, Colorado.

Teeth-whitening treatments — done either in a dentist's office or using an over-the-counter product — contain harsh chemicals that remove stains, but they can also remove the enamel, leading to tooth sensitivity. Several studies have investigated ways to lessen pain after in-office teeth-whitening treatments. A 2018 study in Operative Dentistry found that patients taking acetomeniphin/codeine before treatment did not reduce pain, so more dramatic measures are likely needed. A 2016 study in Lasers in Medical Science found that irradiating teeth with a low-level red laser with an infrared diode after a whitening treatment reduced pain levels significantly. A 2018 study published in The Journal of the American Dental Association found that applying a densitizing gel before whitening significantly reduced tooth sensitivity after treatment.

Another potential solution is changing the formula of whitening products. A 2017 study published in Clinical Oral Investigations found that reducing the acidity in bleaching gels resulted in significantly less pain with the same whitening results. 

"Sensitive teeth never completely disappear," Culotta-Norton said. "Symptoms may be less or even seem to go away for a while but unless the reasons why a person's teeth become sensitive are completely eliminated the sensitivity will come and go."

There are several types of treatment available, and each dentist has his or her favorites that they are most likely to recommend, according to Culotta-Norton. She stressed that there is no single treatment option that works for everyone. "Proper diagnosis of the reason for the sensitivity is essential in treating sensitivity. If the reason for the sensitivity is addressed, the treatment chosen will be more successful in decreasing pain. If the dentist just treats sensitivity without addressing the reason for it the problem will continue and get worse," she said. 

The following are some at-home treatments suggested by the Cleveland Clinic:

  • Desensitizing toothpaste. There are several brands of toothpaste for sensitive teeth available. Your dentist may recommend one or you may have to try different brands until you find the product that works for you. Be sure to use fluoridated toothpaste for sensitive teeth, not tartar-control toothpaste. Try spreading a thin layer of the desensitizing toothpaste on the exposed tooth roots before bed.
  • Use a soft-bristled toothbrush.
  • Avoid highly acidic foods.
  • Use a fluoridated mouthwash daily.
  • Avoid teeth grinding. Consider getting a mouth guard.

The following are some dental procedures that may reduce tooth sensitivity, according to the American Dental Association:

  • Bonding, crowns or inlays. These may fix a tooth flaw or decay that is causing sensitivity.
  • Fluoride gel or varnish.
  • Surgical gum graft. This will protect the root and reduce sensitivity if the gum tissue has eroded from the root.
  • Root canal. This is a last-resort treatment for severe tooth sensitivity that has not been helped by other methods.

The Cleveland Clinic also suggests getting dental sealants applied to the exposed root surface. 

Findings published in 2015 in Caries Research suggest that fluoride alone can't prevent tooth erosion, which can lead to tooth sensitivity, and neither can fluoride combined with other protective agents. The authors suggest that protective products containing titanium tetrafluoride, polyvalent metal ions and some polymers may offer more protection. The authros said more studies were needed to determine the efficacy of these additives. Some toothpastes contain potentially protective polymers, according to Pocket Dentistry. These polymers appear as toothpaste ingredients arboxymethylcellulose, hydroxyethylcellulose and polyethylene glycol. 

In 2014, the FDA approved the use of silver diamine fluoride to treat tooth sensitivity, according to the Association of State and Territorial Dental Directors (ASTDD). The topical treatment has long been popular in Asia and Europe and used to prevent pain and caries. A short-term 2011 clinical trial in Peru published in the Journal of Dental Research found that participants with tooth sensitivity who underwent topical silver diamine fluoride applications saw significantly reduced levels of pain. Silver diamine fluoride application results in a harder tooth surface, helping to prevent further decay. It also protects exposed dentin from potentially painful stimuli. 

Silver diamine fluoride treatments must be applied by a dental practitioner, according to the ASTDD. Typically, silver diamine fluoride is applied twice a year. When applied over spots of decayed dentin, silver diamine fluoride results in a permanent black spot on the tooth. People with silver allergies should not use this treatment.