Wisdom tooth infections. / Pericoronitis
Some wisdom teeth have to be extracted because the tissues around them repeatedly become infected. The term for this condition is "pericoronitis."
What exactly is pericoronitis?
Pericoronitis refers to a bacterial infection located in the tissues that surround the crown portion of a partially erupted tooth.
[A "partially erupted tooth" refers to a tooth that has only part way penetrated through the gums. This may be a transitory positioning because the tooth is in the process of erupting or, in the case of a partially erupted impacted tooth, a permanent one.]
Pericoronitis is caused by bacteria.
Pericoronitis is caused by bacteria (dental plaque) that cannot be adequately cleansed from around the tooth. And as long as the tooth remains partially erupted and impossible to properly clean (which might be forever in the case of an impacted wisdom tooth), a person may experience repeated episodes of pericoronitis.
Why does pericoronitis form?
The crown portion of a tooth forms within a pouch termed the follicular sac (drawn in yellow in our pictures).
At that point in time during its eruption when a tooth first penetrates through the gum tissue, the integrity of this developmental sac is lost and bacterial from the mouth easily enter into this space and find harbor.
Unfortunately, there is no way for a person to effectively clean away these bacteria. And due to this inability, from time to time it is possible for them to cause an active infection, which then spreads to adjacent tissues surrounding the wisdom tooth (as illustrated in our picture below).
Where does the term "pericoronitis" come from?
The term "pericoronitis" breaks down as follows. "Peri-" means "around." The "-coron-" portion of the term refers to the "crown" of the tooth. The suffix "-itis" refers to the presence of infection. So, the word pericoronitis literally means "an infection around the crown portion of a tooth."
What are the signs of having pericoronitis?
The signs of pericoronitis are tenderness and swelling in the gum tissue surrounding the wisdom tooth. This swelling can extend into the face and may be associated with a limited ability to open one's mouth. In extreme cases, the swelling may become so pronounce as to threaten the patency of the person's airway and their ability to breathe.
There can also be severe pain, an unpleasant mouth odor, and even a bad taste coming from the infected area.
How is pericoronitis treated?
People who have pericoronitis should be evaluated and treated by their dentist. In most cases a dentist will place a patient on antibiotics and, if possible, show them methods by which they can flush out ("irrigate") the space between the tooth and gum (the area that harbors the bacteria causing the infection).
How likely is it that a person will experience pericoronitis?
Friedman's (2007) review of dental literature concluded that the incidence rate for a person experiencing pericoronitis in association with a wisdom tooth falls along the lines of 6 to 10%.
In regards to extractions performed, research frequently cites pericoronitis as being the most common reason for wisdom tooth removal. Some studies have placed this number as high as 40 to 59%. (Faculty 1997)
As we discuss below, experiencing a single incidence of pericoronitis does not necessarily constitute a valid reason to extract a wisdom tooth. The tooth's prognosis in regards to being able to erupt properly (or not being able to with the associated expectation that the patient will experience pericoronitis repeatedly) should typically be the basis on which this decision is made.
Partially erupted teeth are not necessarily impacted teeth.
Even those wisdom teeth that eventually fully erupt into normal and proper alignment go through a transitional period where they are only "partially erupted." This is because it takes some time for a tooth to fully penetrate through the gums and achieve its final positioning. During that time frame when the wisdom tooth is only part way through the gums, it is at risk for developing pericoronitis.
This means that when a dentist evaluates a patient experiencing pericoronitis they need to determine whether the tooth's "partial eruption" status is simply a transitory phase of the normal tooth eruption process. Or if the wisdom tooth is impacted (meaning the tooth will always remain partially erupted) and therefore it is likely that pericoronitis will be a recurring problem.
In the first case the dentist's approach will be to actively manage the patient's current condition (prescribe antibiotics, irrigate the area). Then, over time as the tooth more fully erupts, the potential for pericoronitis recurrence will diminish.
In the later case, where the impacted tooth's positioning is not expected to resolve normally and therefore always remain at risk for experiencing pericoronitis, the wisdom tooth is typically extracted.