What are wisdom teeth?

Structure and Functions

The third molars are called wisdom teeth because they appear much later than the other permanent teeth, at an age when people are supposedly wiser than they were as children. The average number of wisdom teeth is four, but it is possible to have more or less. They come in behind the second molars on the upper left, upper right, lower left, and lower right. Wisdom teeth are no longer considered necessary. People now eat soft diets and have better dental care, which prevents decay and molar loss. Thus, the second molars are sufficient.

Wisdom teeth become impacted if the tooth cannot erupt because of gum or bone hardness and/or lack of space. Impacted wisdom teeth fall into four categories: Mesioangular refers to a tooth that is angled forward toward the front of the mouth; vertical refers to a tooth that does not fully erupt through the gum line; horizontal refers to a tooth that angles forward, growing into the roots of the second molar; and distoangular refers to a tooth that is angled backward.

Disorders and Diseases

Wisdom teeth may become infected when saliva, bacteria, or food particles collect around them, causing pain, decay, swelling, and, in severe cases, trismus (inability to open the mouth fully). The infection can spread to the cheek and neck. In rare cases, the infection has been linked to heart disease. Infected wisdom teeth are usually extracted.

Wisdom teeth may also be removed even if no infection is present, such as when a younger patient is having lengthy orthodontic treatment to straighten teeth, as unremoved wisdom teeth may erupt and damage the straightened teeth. Also, older patients who need dentures should have any latent wisdom teeth removed. Should wisdom teeth erupt beneath a denture, it could cause severe irritation. The patient could suffer considerable pain and must replace the dentures, as the shape of the jaw will have changed.

There is a possibility of nerve damage during tooth extraction. Two nerves are close to the lower wisdom teeth. One of them, the inferior alveolar nerve, supplies sensation to the lower teeth on the right and the left side of the mouth, and a sense of touch to the right and left half of the chin and lower lip. The second nerve, the lengual, supplies a sense of touch and taste to the tongue and the gums. Injury can occur as a result of a faulty extraction or by a dental drill. Such injuries are rare, but damage can be prolonged or permanent.

Treatment after extraction usually consists of packing gauze pads in the hole for half an hour to control bleeding. Swelling is controlled by the use of cold packs. After twenty-four hours, rinsing with warm saltwater every two hours will help healing. For minor discomfort, aspirin or ibuprofen can be taken.

Perspective and Prospects

Researchers from the United States and Australia have made stem cell studies on the dental pulp found in extracted wisdom teeth. These stem cells have the potential to save injured teeth and grow jawbone. As research progresses, it may be possible to use these stem cells to restore cells damaged by conditions such as Parkinson’s disease.

Bibliography

Fields, Helen, and Margaret Mannix. “Not so Wise Wisdom Teeth.” U.S. News and World Report 139, no. 12 (October 13, 2005): 53.

Goldie, Maria Perno. “Stem Cell Research: A New Era.” Access 19, no. 9 (November 2005): 28-30.

“Hold On to Your Wisdom Teeth.” Consumer Reports on Health 5, no. 8 (August 1993): 84-85.

"Impacted tooth." MedlinePlus. April 5, 2012.

“Just Ask Us.” Current Health 27, no. 2 (October 2000): 94.

Roeder, Felix. "Necessity of 3D Visualization for the Removal of Lower Wisdom Teeth: Required Sample Size to Prove Non-Inferiority of Panoramic Radiography Compared to CBCT." Clinical Oral Investigation. 16.3 (2012): 699–706.

Steinmeh, Eric. “Yanking Those Wisdom Isn’t Always Necessary.” Health 19, no. 8 (October 2005): 91.

"Wisdom Teeth." American Association of Oral and Maxillofacial Surgeons. July 25, 2013.