While the jaws are not subject to affections peculiar to these parts, there may be seen in them peculiar expressions of general conditions, made so by virtue of environment or complexity of tissues. Most of the acute infections of the jaw bones are propagated from the teeth or the tooth sockets. There may be periostitis and osteomyelitis, and these may be followed by a sclerosing process or acute suppuration. The jaws are prone to be thus affected in consequence of the acute exanthems and the infectious fevers, while the effects of mercury and phosphorus have been mentioned. The treatment of the inflammatory affections here is the same as elsewhere, i. e., early incision and complete evacuation of pus, with removal of necrotic bone or other tissue. Many sequestra may be removed from within the mouth in such a manner as to avoid disfiguring scars. When external sinuses complicate the case, incisions through the skin should be made. These may be so planned as to coincide with the natural wrinkles or folds of the face.
The temporomaxillary joint is a locality of considerable interest. Dislocations take place here in consequence of blows or of violent muscular effort, and are easily recognized because of the fixation and displacement which they produce. Ordinarily they are easy of replacement. These luxations may be unilateral or bilateral. As the result of violence the condyle has been driven upward through the base of the skull, the violence producing such injury usually being fatal. Aside from these injuries to the grosser structures the temporomaxillary joint is not infrequently the site of acute synovitis, or more extensive inflammation, usually propagated from surrounding tissues, but sometimes the result of distant infection. In phlegmons of this region the structures of the joint rarely escape a sympathetic participation, while parotid abscess and similar collections of pus may penetrate the joint and destroy it. Again it is occasionally the site of a postgonorrheal arthritis, or it may suffer as do other joints after the exanthems and acute fevers. It also occasionally becomes involved in the disturbances accompanying irregular eruption of the last molar, i. e., the wisdom tooth; in other words, it may suffer just as may any other joint in the body, and from similar causes.
Ankylosis of the temporomaxillary joint is an infrequent result of its involvement in serious disease, or may result from lesions of the adjoining tissues, as from the cicatricial deformity following noma, burns, and the like. Thus we may have either a true or a spurious ankylosis of this joint, in either case the resulting condition being intractable and exceedingly difficult to manage. When it can be foreseen as a consequence of extrinsic disease it may be prevented by the insertion of a mouth-gag, and more or less frequent and forcible stretching, or by wearing some suitable apparatus between the teeth which shall keep the jaws apart, and which may be used at night. A pseudo-ankylosis produced by cicatricial bands, and long neglected, will become genuine, and require as radical an operation as though it had been interosseous from the outset.
For the relief of such conditions various operations have been devised, in each of which the formation of a false joint is contemplated, it depending upon the exigencies of the case whether this shall be produced by the division of the horizontal ramus in front of the masseter, or of the ascending ramus behind the masseter, or whether there shall be actual resection of the temporomaxillary joint, with division of the neck and removal of the condyle. The latter procedure is the more ideal, at the same time the more difficult, and the more likely to permit injury to the branches of the facial nerve, with consequent paralysis of the orbicularis and the facial muscles.
I have elsewhere described a peculiar condition of relaxation of the temporomaxillary ligaments, by which there is a recurring subluxation of the joint, noticed most often during eating and accompanied by a snapping sound. This is usually unnoticed by the patient, but is often observed by others. It is painless, harmless, and not ordinarily amenable to treatment. (See [p. 528].)
Tumors of the jaws proper include mainly cysts, which are often connected with odontomas, benign tumors, such as fibroma, chondroma, and osteoma, most often of mixed type, and the malignant tumors, i. e., sarcoma, carcinoma, and endothelioma. Malignant tumors primary to the bone are usually of sarcomatous type, though these may include the endotheliomas. Carcinoma and epithelioma do not originate in bone texture, but may easily spread to and involve it. Thus many cases of advanced epithelioma of the lip involve the bone as well as the other neighboring tissues.
Epulis is a somewhat vague term, which has been applied to tumors which spring from and mainly involve the fibrous texture of the gum and the periosteum covering the alveolar process. The term itself simply implies a tumor upon the gum. Microscopically these tumors are usually of the giant-cell type of fibrosarcoma, and are among its least malignant varieties. They pursue a slow course, gradually loosening one tooth after another as they invade the tooth sockets, show very little tendency to spread rapidly, and are usually sharply circumscribed growths, tending to ulceration. They seem to be products of irritation. When removed they rarely recur. The surgeon should excise involved tissue in order to be on the safe side, sacrificing teeth, gum, and alveolar process as widely as necessary for the purpose. Formerly the epulides were made to include different expressions of fibroma and sarcoma involving the gum, but the name is so vague that it would be better to speak of each of these cases as its histological characteristics may indicate.
Benign tumors involving the entire bone may necessitate its removal, but most of the dentigerous bone cysts may be laid open, their contents evacuated, their size reduced, and the remaining cavity allowed to fill with granulation tissue; while malignant tumors call for sacrifice of every portion of tissue involved, often including the skin, and in the upper jaw much of the complicated structure of the nasal cavity, or in the lower jaw the loss of the tongue or a large portion of the floor of the mouth. A cancer of the lower jaw may be removed, with permanent good result, but a true cancer of the upper jaw should be seen early and mercilessly extirpated if the result is to be more than temporary.
OPERATIONS UPON THE JAWS.
Aside from those already mentioned the principal operations upon the jaws consist of partial or complete excision.