Wisdom tooth infections - Pericoronitis.

- Why does the infection occur? | How is it treated? | Statistics - Incidence rates. | If you've experienced pericoronitis should your tooth be extracted?

1) What is pericoronitis?

"Pericoronitis" refers to a bacterial infection located in the soft tissues that surround the crown portion of a partially erupted tooth. Most cases involve wisdom teeth.

  • The "crown" of a tooth is its non-root portion. That part that is normally positioned above the gum line.

  • A "partially erupted tooth" is one whose crown portion has only part way penetrated through the gum tissue (see picture below).

    This positioning may just be temporary because the tooth is in the process of erupting or, in the case of a partially erupted impacted tooth, a permanent one.

Where does the term "pericoronitis" come from?

The term breaks down as follows: 1) "Peri" means "around."   2) The "coron" portion of the word refers to the "crown" of the tooth.   3) The suffix "itis" refers to the presence of inflammation (the body's response to the infection).

2) Details about Pericoronitis. -

a) It's caused by bacteria.

Pericoronitis is an infection. It's caused by normal oral bacteria, like those found in dental plaque.

A partially erupted wisdom tooth.

It's the gum relationship around a partially-erupted tooth that allows pericoronitis to occur.

It occurs when bacteria accumulation builds up but cannot be adequately cleansed away from around a partially erupted tooth due to the configuration of the gum tissue that surrounds it.

Since there's often just a delicate balance between the presence of bacteria and a persons body's defense against them, if something tips this balance (illness, tissue trauma, increased numbers of bacteria or a better food supply for them) an infection can be triggered.

Transient vs. persistent.

As long as a tooth remains partially erupted and is impossible to properly clean, a person may experience repeated episodes of pericoronitis with that tooth.

  • Transient - In cases where the tooth is in the process of coming in, the problem should just be a transitory one. Once the tooth fully clears the gum line, it should be possible to properly clean (brush and floss). If so, no more episodes of infection should occur.
  • Persistent - In cases where the tooth is both partially erupted and impacted (meaning no further progress through the gum tissue will occur), the person can expect to experience repeated infections.

b) Why does pericoronitis form?

The crown portion of a tooth forms within a pouch termed the follicular sac (drawn in tan in our illustration).

Pericoronitis is an gum infection that surrounds a wisdom tooth.

The infection is harbored in the developmental sac (tan) around the tooth.

The sac is penetrated.

At that point in time during the eruption process when a tooth first pokes through the gum tissue, the integrity of its developmental sac is lost and bacteria from the mouth easily flood into this space and colonize it.

The sac is a non-cleansable area.

Unfortunately, there is no way for a person to effectively clean this space. And due to this inability, from time to time it is possible for the bacteria it harbors to cause an active infection, which then spreads to adjacent tissues surrounding the wisdom tooth (as illustrated in our picture).

Pericoronitis around a lower wisdom tooth.

The initial formation of infection around a lower partially erupted wisdom tooth.

d) What are the signs and symptoms of having pericoronitis?

The signs of pericoronitis include:

  • Redness, tenderness and swelling in the gum tissue immediately surrounding the wisdom tooth.
  • The swelling can extend into the face and neck and may make it difficult for the person to open their mouth.
  • There can also be moderate to severe pain, an unpleasant mouth odor, and even a bad taste coming from the infected area.
Some cases can be life threatening.

Due to the anatomy of the region, it's possible for an infection located in the soft tissues surrounding a lower wisdom tooth to spread rapidly and extensively in the region of the throat and neck.

If so, the extended tissues may interfere with the person's ability to breathe and swallow, thus causing a potentially life-threatening situation. These cases may require hospitalization and possibly surgery to drain the infection.

Especially for this reason, if you notice the signs and symptoms of developing pericoronitis, you should advise your dentist sooner rather than later.


How is pericoronitis treated?

This condition needs to be evaluated and treated by your dentist. In most cases they will:

  • Reduce the bacterial load in the infected area by scraping or irrigating (flushing) away as much accumulated debris as is possible.
  • Place you on a course of oral antibiotics. It usually takes on the order of 24 hours for oral antibiotics to start to create their affect.
  • Prescribe an antibacterial oral rinse (frequently chlorhexidine) that you can use to clean the infected area and reduce its bacterial load.
  • If access exists, show you methods by which you can flush out the space between the tooth and gum tissue (the area that harbors the bacteria causing the infection) using an "irrigating" (blunt-tipped) syringe.

In the case that a decision is made that your wisdom tooth should be extracted, your dentist will need to wait until your infection has resolved before the procedure can be performed. In relatively routine cases, and where a course of antibiotics is taken and irrigation is performed, a time frame of at least a week is usually required.

A dental x-ray showing where pericoronitis occurs.

X-ray diagram showing where the infection initiates.

4) Statistics - How frequently do people experience pericoronitis?

  • Friedman's (2007) [page references] review of published 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%.
  • Research frequently cites pericoronitis as being the most common reason for wisdom tooth removal. Some studies place this number as high as 40 to 59% of cases. (Faculty 1997)

As we explain below, experiencing a single episode of pericoronitis does not necessarily constitute a valid reason to extract a wisdom tooth. The tooth's outlook in regard to its ability to ultimately fully erupt (clear the gum line) should be the basis on which the decision is made.

If you experience pericoronitis, does your tooth need to be pulled?

a) All teeth are just partially erupted at some point.

Just like every other tooth that comes in, even wisdom teeth that eventually fully erupt into normal and proper alignment go through a transitional period where they are only "partially erupted."

That's because it takes some time for a tooth to fully penetrate through the gums and achieve its final positioning. And during that time frame when the wisdom tooth is only part way through the gums, it is at risk for developing pericoronitis.

b) Partially erupted teeth are not necessarily impacted teeth.

When a dentist evaluates a patient that has pericoronitis they need to determine whether the tooth's partially erupted status is simply a transitory phase of the normal eruption process. Or if it's instead impacted (meaning the tooth will always remain partially erupted).

In the first case, the dentist's approach will be to actively manage the patient's current condition (prescribe antibiotics, irrigate the area, etc...). It's expected then, over time as the tooth more fully erupts, that its potential for additional episodes will diminish.

In the latter case, where the impacted tooth's positioning is not expected to resolve normally and therefore it will always remain at risk for recurring infections, the wisdom tooth should be extracted.


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