Swellings & Abscesses

Swelling in the oral cavity is usually caused by an inflammatory process stimulated by microbial irritation, sometimes by allergic reaction or mechanical trauma (for example, biting trauma to buccal mucosa). Swelling often helps to localise the involved tooth, but sometimes swelling is so diffuse and extensive that additional tests are needed to find the source of the swelling.

An abscess is caused by microbial irritation, it is most common in connection with acute apical periodontitis. The reaction between host defence and microbes sometimes results in the formation of a necrotic area with pus. The main components in pus are dead and living bacteria, leukocytes and tissue remnants. If the apical abscess penetrates the cortical bone, it can be seen as a localised swelling of the mucosa, typically at the apical region of the tooth. As long as the abscess has not perforated the periosteum, the abscess is hard, while perforated abscesses are fluctuant when touched with a finger or a blunt instrument. Endodontic abscesses are far more common than periodontal abscesses, and other origins are also possible.