Why are my teeth sensitive?

April 15, 2011

What is a sensitive tooth?

One of the most common reasons patients show up in my office is a complaint about tooth sensitivity. First, let’s define sensitive. Sensitive is NOT a constant dull ache or pain that comes on spontaneously or is accompanied by swelling. Sensitive is a temporary, sharp – almost electrical pain – caused by a stimulus like exposure to hot or cold temperatures, acidic foods, sweets, touch or biting. Sensitivity can be random or caused by some rare neurologic disorders, but most of the time it is caused by stimulation of the nerve fibers inside the tooth. Since teeth only contain pain nerve fibers, the only signal that can be sent is “ouch that hurts!” As with many aches and pains tooth sensitivity may be the beginning of something like a cavity, or a sign of a chronic, ongoing problem or habit that is causing your body to react. Either way, it is an uncomfortable nuissance that should be checked out by a dentist if it persists. Some of the most common complaints are, “ My tooth is sensitive when I brush my teeth, drink cold water, or prod with my fingernail along a tooth’s gum line.” Of course you could stop poking your tooth with your fingernail, but many people just look for trouble. Normally the tooth’s nerve fibers are covered by the gum or the enamel cap of the tooth, which acts as a protective coating for the nerve fibers.

Damage done by overzealous toothbrushing

Gum and tooth worn away by overzealous toothbrushing, Ouch!

When the enamel or gums are worn away the nerve is stimulated, becoming hyperactive as the nerve fibers from inside the tooth come to the surface of the root and are exposed to the outside world. Since the only fiber inside a tooth is a pain fiber, the tooth can only “feel” pain when stimulated. The loss of the protection can occur from abrasion or erosion or a combination of both.

Exposure of the root surface can be caused by overzealous brushing, improper brushing techniques, a hard tooth brush, or previous periodontal (gum) treatments. Often times we see that brushing habits or a particular tooth’s positioning in the mouth cause the bristles of your toothbrush to wear away the gum and root causing sensitivity. The most common is the wearing away of the upper left hand gum (for right handed brushers) near the eye tooth because it is the easiest place to brush vigorously.

tooth loss caused by wear and acid reflux

Tooth erosion caused by acid reflux

If the cause of the nerve exposure is related to higher than normal acidity levels in your mouth, as can occur with certain foods, medications, or acid reflux, we often find multiple teeth that are sensitive. Soft drinks, sports drinks, energy drinks and certain fruit juices are very acidic and among the biggest causes of tooth sensitivity and tooth decay. Some medications dry your mouth by reducing salivation; however, this also reduces the protection provided by the bathing and cleansing action of saliva. Many people who suffer from acid reflux, find that their back teeth become sensitive from the acid reflux that occurs when they are laying down at night.

So how can we treat sensitive teeth?

The good news is that generally if you treat the cause of a sensitive tooth early on, especially when related to abrasion or erosion, you can resolve it before the nerve is damaged or requires more extensive treatment. If the cause is overzealous brushing, simply changing your habits, toothbrush and technique can usually stop the sensitivity. If enamel erosion is the cause, reducing your intake of acidic beverages, and sugar can often help to eliminate sensitivity, however if acid reflux is the issue, a consultation with your doctor may be helpful.

You can treat sensitive areas yourself by using a desensitizing toothpaste or the addition of a flouride rinse to your oral hygiene routine. Virtually any mouthwash with flouride including Act or Listerine Restore will help. Additionally, these flouride rinses will strengthen the teeth and help to prevent cavities. Unfortunately, these treatments require several applicatons and time (usually about two weeks) to work. If you try these solutions and don’t notice some alleviation, you should probably consult your dentist. We have stronger desensitizing treatments, which include special flouride varnishes and sealers. If the area is too difficult to clean or treat with sealers, we can easily place a filling to cover the sensitive area.

Other casues of sensitivity can include decay, a cracked tooth, and grinding, which we’ll explore during your visit. Decay causes teeth to become sensitive because the bacteria release acid which expose and irritate the nerve endings. A tooth with a fracture or broken filling will often be sensitive to cold, but also to biting pressure especially with firm foods like bagels, toast, nuts or popcorn. Sound familiar? This usually occurs when you are happily enjoying french bread or cereal and all of a sudden when biting down you get a sharp, almost electric feeling in a tooth. This kind of sensitivity should be evaluated immediately as the problem can rapidly become worse. A single tooth can sometimes shift and hit too hard causing stress on the nerve and sensitivity.

The most important lesson is to listen to your body and don’t let the problem linger. Your teeth may be trying to tell you something important.

This of course is not a complete explanation of any of these problems, options or treatments. It is the first installment in our effort to inform you and make you a more educated patient.

- Geoff Bell