Fig. 247.—Cario-necrosis of Mandible.
Acute osteomyelitis occasionally attacks the mandible, less frequently the maxilla. Pus rapidly forms under the periosteum, and a considerable area of bone may undergo necrosis.
In cancrum oris, also, the bones are frequently attacked and may undergo necrosis.
The treatment is to let out the pus, and, whenever possible, this should be done from the mouth to avoid a cicatrix on the face. When the angle or the ascending ramus of the mandible or the facial portion of the maxilla is involved, it is not possible to avoid making an external opening. Drainage is secured, and the mouth kept sweet by the frequent use of antiseptic washes. When the condition is due to a carious stump or to an unerupted tooth, this should be extracted at the same time as the abscess is opened.
The separation of a sequestrum is usually slow, taking from two to four months according to the acuteness of the infection and the extent of the necrosis. In the mandible the sequestrum becomes surrounded by a sheath of new periosteal bone, so that, even if the greater part of the jaw undergoes necrosis, the arch is reproduced, and after removal of the sequestrum little or no deformity results. The sequestrum can usually be removed after dividing the mucous membrane and gouging away a portion of the outer aspect of the new sheath. The cavity is packed with iodoform or bismuth gauze. When the ascending ramus is involved, precautions must be taken to prevent fixation of the jaw taking place during the healing process. In the maxilla no new case is formed, and deformity results from sinking in of the cheek, unless this is prevented by wearing a plate made by the dentist.
Tuberculous disease is comparatively rare. It is occasionally met with on the orbital margin of the maxilla and in the region of the zygomatic (malar) bone. In the mandible it usually occurs near the angle. Stockman isolated the tubercle bacillus from a series of cases of “phosphorus necrosis” investigated by him. The sinuses that form when a cold abscess bursts on the surface are peculiarly intractable and only heal after the diseased bone has been removed, leaving a characteristically depressed scar, which is adherent to the bone.
Syphilitic affections are also rare. A localised gumma may develop in the neighbourhood of the angle of the mandible, or the whole of the body of that bone may be the seat of a diffuse gummatous infiltration ([Fig. 248]). In either case the clinical importance of the condition lies in the fact that it is liable to be mistaken for a new growth, such as an osteo-sarcoma, or for actinomycosis.
