Sensitivity occurs when gums wear away (recede) from the neck of a tooth, or when teeth and fillings are broken, cracked or decayed or the filling is missing.
Understanding how teeth are made helps in dealing with tooth sensitivity. A layer of cementum covers the root of each tooth. Beneath this lies another layer called dentin. When cementum dissolves or is worn away, dentin becomes exposed.
Dentin is made of thousands of tiny tunnels called tubules. These tubules lead directly to the inner core or pulp of the tooth. Pain is felt in the pulp, as it contains the tooth’s nerve and blood vessels. If hot, cold, sweet, sour or acidic foods and drinks stimulate the nerve and cells inside the tooth, sensitivity appears. Even breathing in cold air can trigger pain.
If sensitivity occurs when pressure is placed on the tooth, it may signal a crack or a missing filling. It may also be a decayed tooth. See your dentist or dental hygienist for diagnosis.
Be sure to tell your dental care provider if you have any sensitive teeth. You will be asked for details. An examination of your mouth may show the cause. Together, you can decide on the best treatment.
Cavities are a common cause of sensitivity. Early cavities often have no symptoms. However, bacteria spreading further into the tooth will irritate the nerve. At this point, many people develop cold sensitivity. A dentist or hygienist must diagnose the cause.
Cavities that can be seen are large and have spread quite far into the tooth. However, those developing under old fillings or crowns are more difficult to diagnose. Such cavities are hard to spot, even when looking into the mouth or using x-rays.
Suspect a cavity if the twinge does not go away after using desensitizing toothpaste for a few weeks. If a cavity is the cause, your dentist can place a filling, crown, or other type of restoration in the tooth. However, if a cavity has spread deep into the tooth pulp, a root canal may be needed.
Cracked tooth syndrome is also common. Fine cracks make teeth very sensitive to cold. They are most often found in molar or back teeth. Very large fillings, cavities, clenching or grinding teeth, or a trauma often causes this problem. Biting chewy or hard foods, such as pretzels, is the most common trigger of pain.
To pinpoint the problem area, your dentist will have you bite on a plastic stick. The bite will not feel ‘normal.’
A crown is usually necessary. A filling may work if only one area of the tooth is involved and cracks do not go deep into the tooth. A root canal may also be needed.
If a tooth is highly sensitive for more than three or four days and reacts to both hot and cold temperatures, see your dentist or hygienist. Since pain symptoms for various problems can be similar, what appears to be tooth sensitivity may actually be cavities or infection. Explain when the pain started and whether anything can stop it.
Many factors can lead to tooth sensitivity.
Brushing too hard - 50 to 90 per cent of people use a hard bristled toothbrush, or too much pressure when brushing. Weeks, months, and years of scrubbing can remove the gum tissue over roots.
Tooth whitening or toothpaste with abrasive products - Such products, like baking soda, are major contributors to tooth sensitivity, as they break down enamel and gums.
Plaque - This material is the build up of bacteria that grow on teeth every day. Plaque produces acids as part of its normal life cycle. If it stays along the gumline and exposed root surfaces, this acid attack can also cause sensitivity. If plaque is not removed daily, cavities also result.
Gum disease - Inflamed and sore gums can cause sensitivity. Roots of teeth become exposed as supportive, healthy gum tissue is lost.
Age - As we grow older, wear and tear on teeth slowly breaks down gum and supporting tissue. Tooth sensitivity then appears. This can begin as early as age 25.
Changes in temperature - Once tubules are exposed, extreme changes in temperature cause fluids inside them to flow back and forth quickly. It is the fluid movement that causes the twinge in your teeth.
Cavities - When a tooth decays and the cavity is left unfilled, the exposed nerve is sensitive. (See sidebar).
Acidic foods - If eaten often, foods with a high acid content, such as citrus fruits, soft drinks, and tomatoes, can dissolve tooth enamel. Dentin in the crown of the tooth, or the cementum and dentin in the root, is then exposed.
Cracked teeth - Chipped or broken teeth can fill with bacteria. As bacteria enter tiny tubules in the dentin, the tooth nerve becomes inflamed. A cracked tooth may be sensitive to pressure placed on a specific part of the chewing surface (see sidebar).
Teeth grinding – Wear from grinding and clenching can break down enamel, exposing underlying dentin.
Routine dental procedures - Sensitivity can occur after teeth are cleaned, crowned (‘capped’) or filled. This type of sensitivity is caused by the procedure and is temporary. It usually disappears in four to six weeks. If teeth are sensitive to hot or cold after dental work, a pain reliever may be recommended. If pain does not go away after several weeks, return to your dental office for advice.
Following the advice of your dental care provider can reduce your chances of developing sensitive teeth. Keep your mouth healthy by brushing and flossing properly. Make regular appointments for professional tooth cleaning, brushing and flossing instruction, and fluoride treatments.
Proper brushing is the key to protecting gum health. Use a soft bristled toothbrush. Brush gently and carefully around the gumline. Reduce the pressure you use in brushing your teeth.
Many electric toothbrushes now feature pressure sensors. When you brush too hard, the brush stops or a warning light comes on.
Remember to take two to three minutes to properly brush all tooth surfaces. Most people spend less than 45 seconds on brushing. Plaque then builds up in untouched areas.
Desensitizing toothpaste is a low-abrasion version specially made for sensitive teeth. Regular use can help by plugging the tubules. However, you must use the paste often for it to be effective. You might even use a finger or cotton swab to spread a thin layer of paste on exposed roots before you go to bed. A version containing fluoride is better, as it protects against cavities.
Your dental care provider might also recommend a brush-on fluoride gel, a fluoride rinse, or toothpaste with a high level of fluoride. This helps make teeth less sensitive and provides extra protection against cavities. Such treatments are inexpensive, done at home as you brush your teeth. Fluoride rinses are available without a prescription. You can find them at your local pharmacy or in the dental section of grocery and department stores.
Use the rinse once a day, preferably just before bed. Brush and floss, then swish the rinse around in your mouth and spit it out. For best results, do not eat, drink, rinse, or smoke for at least 30 minutes afterward.
Watch what you eat, and limit acidic foods and drinks in your diet. Frequently eating foods high in acids can gradually dissolve tooth enamel, exposing roots. Acids may also make sensitivity worse.
If you are diagnosed with sensitive teeth, your dentist or hygienist can prescribe any of a variety of treatments. These include in-office treatments, such as applying a desensitizing or protective coating to the teeth. Other products may be used at home. If sensitivity remains severe and persistent, return to your dental office for further evaluation and treatment.