A pericoronitis is an infection around the crown of a tooth that is erupting, or trying to grow into the mouth.  It most often occurs in those age 17-21 in cases where the third molars (wisdom teeth) are coming into the mouth but do not fit all the way. Flabby gum tissue sitting next to, or over, the back of the half-erupted tooth can collect bacteria, food and debris underneath and an abscess/infection  can form.  Typically,  the patient cannot open his or her mouth wide and the pain may travel down into the lymph nodes of the neck.  The lower wisdom teeth are effected much more frequently than the uppers.

A dentist will carefully lift the tissue behind the tooth and clean the area out.  Sometimes a drop of pus and blood will come out when the flap is lifted.  This can afford relief, but usually an antibiotic is added as well. (Amoxicillin 500 mg, 4 times a day for 7-10 days, or erythromycin in case of amoxicillin/penicillin allergy.)  The sure cure is to have the tooth removed and this is usually done by oral surgeons.  In some cases there is just a small flap of tissue over the wisdom tooth and all that is needed is a gum trim.

Often teens put the wisdom tooth surgery off and are treated more than once for this infection before they get the idea and call the surgeon. Flare ups tend to happen at exam time when stress dampens the immune system a bit.  Some of my teen patients have even figured out how to clean under the flap of tissue that covers the back of an erupting lower wisdom tooth themselves with safety pins and various other household tools, but it is not so easy to get down and around the side of the tooth where the pus and debris are trapped.