Odontogenic inflammation is an inflammation caused by tooth. Usually it is caused by teeth with necrotic pulp and radiographicly visible periapical process. Pericoronitis that is caused by difficult eruption of wisdom teeth and an extensive periodontal disease are also possible causes. A fast passage through the bone wall forms subperiostal abscess and further on submucosal. Depending on the relative insertion of the muscle and the apex of the tooth the result will be the formation of either intaroral or extraoral abscess. A possible complication is an inflammation of the lower mandible in the submandibular, submental or sublingual area, and because of the communication between these spaces it may easily spread to the adjacent side or down in the rack and retropharyngeal space. If the inflammation lowers down, it progresses towards the mediastinum causing mediastinitis. The inflammatory products can form an embolus and through the blood stream they can reach the cavernous sinus and cause thrombophlebitis, expanding the brain parenchyma resulting in brain abscess, a life-threatening condition, as well as the abstraction of the meninges, which results in the appearance of meningitis. The complications of odontogenic infections are treated with an antibiotic in combination with surgical cleaning of necrotic and infected tissue as well as the extraction of the teeth.