An impacted wisdom tooth falls into one of several categories. Mesioangular impaction is the most common form (44%), and means the impacted wisdom tooth is angled forward, towards the front of the mouth. Vertical impaction (38%) occurs when the formed wisdom tooth does not erupt fully through the gum line. Distoangular impaction (6%) means the impacted wisdom tooth is angled backward, towards the rear of the mouth. And finally, Horizontal impaction (3%) is the least common form, which occurs when the impacted wisdom tooth is angled fully ninety degrees forward, growing into the roots of the second molar.
A typical distoangular impacted wisdom tooth is the easiest to extract in the maxilla and most difficult to extract in the mandible, while mesioangular impactions are the most difficult to extract in the maxilla and easiest to extract in the mandible.
An impacted wisdom tooth may also be categorized on whether they are still completely encased in the jawbone. If it is completely encased in the jawbone, it is a bony impaction. If the impacted wisdom tooth has erupted out of the jawbone but not through the gumline, it is called a soft tissue impaction.
Sometimes the impacted wisdom tooth fails to erupt completely through the gum bed and the gum at the back of the wisdom tooth extends over the biting surface, forming a soft tissue flap or lid around the tooth called an operculum. Teeth covered by an operculum can be difficult to clean with a toothbrush. Additional cleaning techniques can include using a needle-less plastic syringe to vigorously wash the impacted wisdom tooth with moderately pressured water or to softly wash it with hydrogen peroxide.
However, debris and bacteria can easily accumulate under an operculum, which may cause pericoronitis, a common infection problem in young adults with a partially impacted wisdom tooth that is often exacerbated by occlusion with opposing 3rd or 2nd molars. Common symptoms include a swelling and redness of the gum around the eruption site, difficulty in opening the mouth, a bad odor or taste in the mouth, and pain in the general area which may also run down the entire lower jaw or possibly the neck. Untreated pericoronitis can progress to a much more severe infection.
If the operculum does not disappear, recommended treatment is extraction of the impacted wisdom tooth.
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