The wisdom teeth, officially known as the third molars, are the final set of teeth to emerge in the mouth, typically making their appearance between the ages of 17 and 25. For many people, the jawbone does not have enough space to accommodate these late arrivals, which causes them to become “impacted.” Impacted teeth are partially or completely trapped beneath the gum line or jawbone. Choosing not to remove these problematic, impacted third molars extends beyond simple discomfort. Leaving them untreated can lead to serious complications affecting surrounding tissues, adjacent teeth, and the structural integrity of the jawbone.
Localized Infection and Inflammation
One of the most immediate and common risks of an impacted wisdom tooth is the development of a localized infection called pericoronitis. This condition occurs when the tooth is partially erupted, allowing a flap of gum tissue, known as an operculum, to partially cover the tooth’s surface.
This partially covered area creates an ideal, sheltered environment for food debris and bacteria to become trapped. It becomes impossible to clean this space effectively with normal brushing or flossing, leading to a rapid buildup of plaque and subsequent infection. Symptoms of pericoronitis include severe pain, swelling of the gum tissue, and often a foul taste caused by pus discharge.
The swelling can sometimes become so pronounced that it causes trismus, which is a painful restriction in the ability to fully open the mouth. Although antibiotics can treat an acute flare-up of pericoronitis, the condition is highly likely to recur because the physical flap of gum tissue remains. Without removing the third molar, the persistent trapping of bacteria will continue to trigger repeated cycles of inflammation and infection.
Structural Damage to Adjacent Teeth
Failing to remove an impacted wisdom tooth places the second molar, the healthy, functional tooth immediately in front of it, at risk of irreversible damage. This damage occurs through both decay and physical erosion.
The tight, often angled position of the impacted third molar creates a chronic plaque trap against the distal (back) surface of the second molar. This area is nearly impossible for a toothbrush or floss to reach, leading to a breakdown of the second molar’s enamel and the eventual formation of decay. This decay can progress silently and deeply, potentially requiring extensive restorative work like a large filling, a root canal, or even the extraction of the second molar.
Beyond decay, a deeply impacted or horizontally positioned third molar can exert constant pressure against the root of the second molar. This sustained physical force can lead to external root resorption, where the root structure of the second molar is slowly dissolved or eroded. Root resorption compromises the second molar’s stability and vitality. If left unchecked, the damage can weaken the tooth to the point where it is no longer salvageable. The loss of a functional second molar due to an unremoved wisdom tooth represents a major long-term consequence.
Cysts and Jawbone Complications
A less common but severe risk of retaining an impacted third molar involves pathology within the jawbone itself. Every developing tooth is surrounded by a protective sac of tissue called the dental follicle.
In the case of an impacted tooth, this follicle can undergo a pathological change, filling with fluid to form a dentigerous cyst. These cysts are typically benign but expand slowly within the jawbone, often without causing pain until they become large. As the cyst expands, it progressively destroys the surrounding bone tissue, hollowing out the jaw and potentially damaging the roots of nearby teeth and adjacent nerves.
In rare instances, the lining of the cyst can give rise to a more aggressive, non-cancerous tumor, such as an ameloblastoma, which necessitates a complex surgical procedure to remove the tumor and the affected bone. Furthermore, a large, deep cyst or a significant impaction that has eroded substantial bone volume can weaken the jaw structure. This weakening increases the risk of a pathological fracture of the jawbone, particularly in the angle of the mandible, even from minor trauma.