Acute Acute pericoronitis (i.e. sudden onset and short lived, but significant, symptoms) is defined as "varying degrees of inflammatory involvement of the pericoronal flap and adjacent structures, as well as by systemic complications." Systemic complications refers to signs and symptoms occurring outside of the mouth, such as fever, malaise or swollen lymph nodes in the neck. Chronic Pericoronitis may also be chronic or recurrent, with repeated episodes of acute pericoronitis occurring periodically. Chronic pericoronitis may cause few if any symptoms, but some signs are usually visible when the mouth is examined. Signs and symptoms The signs and symptoms of pericoronitis depend upon the severity, and are variable: Pain, which gets worse as the condition develops and becomes severe. The pain may be throbbing and radiate to the ear, throat, temporomandibular joint, posterior submandibular region and floor of the mouth. There may also be pain when biting. Sometimes the pain disturbs sleep. Tenderness, erythema (redness) and edema (swelling) of the tissues around the involved tooth, which is usually partially erupted into the mouth. The operculum is characteristically very painful when pressure is applied. Halitosis resulting from the bacteria putrefaction of proteins in this environment releasing malodorous volatile sulfur compounds. Bad taste or sour taste in the mouth from exudation of pus. Intra-oral halitosis. Formation of pus, which can be seen exuding from beneath the operculum (i.e. a pericoronal abscess), especially when pressure is applied to the operculum. Signs of trauma on the operculum, such as indentations of the cusps of the upper teeth, or ulceration. Rarely, the soft tissue around the crown of the involved tooth may show a similar appearance to necrotizing ulcerative gingivitis. Trismus (difficulty opening the mouth). resulting from inflammation/infection of the muscles of mastication. Dysphagia (difficulty swallowing). Cervical lymphadenitis (inflammation and swelling of the lymph nodes in the neck), especially of the submandibular nodes. Facial swelling, and rubor, often of the cheek that overlies the angle of the jaw. Pyrexia (fever). Leukocytosis (increased white blood cell count). Malaise (general feeling of being unwell). Loss of appetite. The radiographic appearance of the local bone can become more radiopaque in chronic pericoronitis. Causes Pericoronitis occurs because the operculum (the soft tissue directly overlying the partially erupted tooth) creates a "plaque stagnation area", which can accumulate food debris and micro-organisms (particularly plaque). This leads to an inflammatory response in the adjacent soft tissues. Sometimes pericoronal infection can spread into adjacent