Alveolar osteitis, also known as dry socket, is inflammation of the alveolar bone (i.e., the alveolar process of the maxilla or mandible). Classically, this occurs as a postoperative complication of tooth extraction. Alveolar osteitis usually occurs where the blood clot fails to form or is lost from the socket (i.e., the defect left in the gum when a tooth is taken out). This leaves an empty socket where bone is exposed to the oral cavity, causing a localized alveolar osteitis limited to the lamina dura (i.e., the bone which lines the socket). This specific type is known as dry socket and is associated with increased pain and delayed healing. Dry socket occurs in 0.5% to 5% of routine dental extractions, and in about 25–30% of extractions of mandibular (lower) wisdom teeth that are impacted (buried in the bone of the lower jaw, erupting during adulthood). The pain of dry socket may appear as early as three days after surgery, but a patient who has gone a full week without experiencing this pain is highly unlikely to develop it. Signs and symptoms Since alveolar osteitis is not primarily an infection, there is not usually any pyrexia (fever) or cervical lymphadenitis (swollen glands in the neck), and only minimal edema (swelling) and erythema (redness) is present in the soft tissues surrounding the socket. Signs may include: An empty socket, which is partially or totally devoid of blood clot. Exposed bone may be visible or the socket may be filled with food debris which reveals the exposed bone once it is removed. The exposed bone is extremely painful and sensitive to touch. Surrounding inflamed soft tissues may overlie the socket and hide the dry socket from casual examination. Denuded (bare) bone walls. Symptoms may include: Dull, aching, throbbing pain in the area of the socket, which is moderate to severe and may radiate to other parts of the head such as the ear, eye, temple and neck. The pain normally starts on the second to fourth day after the extraction, and may last 10–40 days. The pain may be so strong that even strong analgesics do not relieve it. Intraoral halitosis (oral malodor). Bad taste in the mouth. Causes The cause(s) of dry socket are not completely understood. Normally, following extraction of a tooth, blood is extravasated into the socket, and a blood clot (thrombus) forms. This blood clot is replaced with granulation