The four permanent adult teeth at the very back of the mouth are known as wisdom teeth, or third molars. These teeth are the last to develop, typically beginning to emerge through the gums between the ages of 17 and 25. For many people, the jaw is simply too small to accommodate these final molars, which can lead to a range of complications. Due to this common lack of space, wisdom teeth removal is one of the most frequently performed surgical procedures globally. The decision to remove them is highly individualized, depending on how they develop and whether they pose a threat to oral health.
The Prevalence of Wisdom Teeth Extraction
Surgical extraction is a common experience for most people in Western populations. Estimates suggest that approximately 65% to 85% of adults will have at least one wisdom tooth removed during their lifetime. This high rate is largely driven by the fact that the vast majority of third molars do not erupt into a functional, healthy position.
The American Association of Oral and Maxillofacial Surgeons estimates that around 90% of Americans have at least one wisdom tooth that is impacted, meaning it is partially or completely trapped beneath the gum line or jawbone. This impaction is the primary reason for extraction, even if the tooth is not yet causing pain. In the United States alone, an estimated 5 million people undergo wisdom tooth removal surgery annually.
This widespread need for removal is considered a consequence of human evolution. Modern diets require less forceful chewing, leading to a reduction in jaw size that leaves insufficient room for the third molars to erupt fully and correctly. Consequently, most people will require the removal of at least one third molar to prevent future complications.
Clinical Criteria Requiring Removal
The need for extraction is generally determined by the presence of pathology or a significant risk of future oral disease. Impaction occurs when the tooth is obstructed from fully erupting by the jawbone, gum tissue, or an adjacent tooth. This condition is classified by the angle at which the tooth is positioned within the jaw.
Impaction types include mesial (angled forward toward the second molar), distal (angled toward the back of the mouth), vertical (straight up but trapped), and horizontal (lying completely on its side). Any of these positions can lead to a chronic, low-grade infection known as pericoronitis, which is the inflammation of the gum tissue surrounding a partially erupted tooth.
Pathology is another major indicator for removal, often involving damage to the adjacent second molar. An impacted tooth can cause external root resorption, where pressure slowly erodes the root structure of the neighboring tooth. The lack of space also makes partially erupted wisdom teeth difficult to clean, leading to decay (caries) that cannot be restored with a simple filling. More severe pathologies include the development of fluid-filled sacs called cysts or, rarely, tumors around the crown of the impacted tooth. These growths can destroy significant amounts of surrounding jawbone and necessitate immediate surgical intervention.
When Wisdom Teeth Can Be Left Alone
A smaller but significant group of people can safely retain their wisdom teeth without the need for surgical intervention. These third molars are considered healthy when they have fully erupted into the mouth and are in a functional position, meaning they align correctly with the opposing teeth. The teeth must also be completely asymptomatic, with no signs of current pain, swelling, or infection.
The ability to maintain consistent oral hygiene is another defining factor for retention. If the wisdom tooth is fully erupted and positioned so that a patient can easily brush and floss around it, the risk of decay and periodontal disease is significantly reduced. In these cases, the benefit of retaining the tooth outweighs the risks of surgery.
When wisdom teeth are deemed asymptomatic and disease-free, dentists often recommend a strategy of “watchful waiting.” This conservative approach involves regular clinical and radiographic monitoring, typically using panoramic X-rays every one to two years. This ongoing assessment is important because a healthy tooth can still develop problems, such as decay or gum disease, as a person ages, potentially requiring removal later.