“Pericoronitis is an inflammation of the soft tissues surrounding the crown of the third molar during eruption, and the obstruction of the third molar is the main cause of pericoronitis. Etiology: It is often caused by the malposition of the third molar, food debris and bacteria lurking in the blind pockets that cannot be easily removed; it can also be caused by injury that decreases local resistance, bacterial multiplication, combined with cold, lack of sleep, excessive fatigue, women’s menstrual cycle and other factors that decrease systemic resistance, causing an acute attack of pericoronitis. Symptoms: The main manifestation is the affected side of the molar area swelling pain and discomfort, open mouth is restricted, so that the teeth closed, so that the patient eating, chewing, swallowing are difficult, because of poor oral hygiene can appear bad breath, serious cases can appear body temperature, headache, chills, loss of appetite and other general discomfort. Treatment: The treatment of pericoronitis of “wisdom teeth” should be started early and divided into local and systemic treatment. 1, systemic treatment in addition to symptomatic treatment such as pain relief, mainly the application of antibiotics, such as taking sulfonamide and intramuscular injection of toxin, etc.. 2, local treatment to gingival pouch cleaning on the most important, through repeated rinsing, to remove the food debris and secretions. Once a day. Can also be used acupuncture, closed and other therapies to analgesic, anti-inflammatory, improve mouth opening and other effects. 3.For the formation of pericoronal abscess, incision and drainage should be performed under local anesthesia, while for the vertical obstruction that has enough position to erupt, and there is a pair of teeth together, pericoronal gingival flap removal is feasible to make it erupt. 4. If the tooth cannot erupt, it should be extracted after the acute inflammation is controlled. Long-term medication alone, without extraction of the blocked tooth, is bound to cause recurrent attacks of pericoronitis.