Pericoronitis - Diagnosis

Diagnosis

The diagnosis is usually clinical, but it is not always straightforward. Severe swelling and restricted mouth opening may prevent examination of the area. For pericoronal infection to occur, there must always be some communication between the tooth and the oral cavity. However, the wisdom tooth may be so buried by soft tissue that it is not visible in the mouth, and careful examination with a dental probe immediately behind the second molar may be needed to discover the communication.

The wisdom teeth are often hard to keep free of dental plaque due to their posterior position in the mouth and also because impacted teeth create areas which are difficult to access due to their angulation. Dental caries (tooth decay) of the wisdom tooth and of the distal surface of the second molar is common. Tooth decay may cause pulpitis (toothache) to occur in the same region, and this may cause pulp necrosis and the formation of a periapical abscess associated with either tooth. Food can also become stuck between the wisdom tooth and the tooth infront, termed food packing, and cause acute inflammation in a periodontal pocket when the bacteria become trapped. A periodontal abscess may even form by this mechanism. In these cases the pain will not be due to pericoronitis, even though signs of chronic pericoronitis may be also evident around the partially erupted wisdom tooth. Pain associated with temporomandibular pain dysfunction and myofascial pain also often occurs in the same region. They are easily missed diagnoses in the presence of mild and chronic pericoronitis, and the latter may not be contributing greatly to the individual's pain. It is rare for pericoronitis to occur in association with both lower third molars at the same time, despite the fact that many young people will have both lower wisdom teeth partially erupted. Therefore bilateral pain from the lower third molar region is unlikely to be caused by pericoronitis and more likely to be muscular in origin.

Sometimes a "migratory abscess" of the buccal sulcus occurs with pericoronal infection, where pus from the lower third molar region tracks forwards in the submucosal plane, between the body of the mandible and the attachment of the buccinator muscle to the mandible. In this scenario, pus may start to spontaneously discharge via an intra-oral sinus located over the mandibular second or first molar, or even the second premolar. This may cause diagnostic confusion and even lead to dental treatment being carried out on the wrong tooth.

Radiographs are of little benefit in the diagnosis of acute pericoronitis except to rule out pulpitis or another cause of the pain. However, often they are needed to properly assess the position and status of the wisdom teeth, necessary information upon which the choice of treatment is made.