Search

The importance of the position of the second mandibular molar in the complete denture has been developed. A technique has been offered for the accurate positioning of this molar in the artificial complete and free-end partial denture arch. This technique considers the physiology of the part and reconstructs any changes in the structure of the adult mandible as they are related to tooth position. Through this method, it is possible to relocate the complete denture arch in its correct anteroposterior relation to the masticatory muscle mass, to determine the anteroposterior size of the molar teeth, and to establish the correct width of the arch at the region of the second molar tooth. The action of the temporalis muscle has been described with the thought that we must claim less for its action than has been done. The primary articulation of the mandible to the skull has been discussed. A few of the important implications have been pointed out as they relate to this subject.

The clinical nature of the mandibular articulation has been outlined. A fourphase method for diagnosing disorders of the mandibular articulation has been presented. Emphasis has been focused on the facts that the mandibular articulation has the capacity for self-injury, that malocclusion is only one of the many causes of these disorders, and that occlusal balancing techniques are not always indicated as a therapeutic measure. This article emphasizes the importance of discovering all factors which interfere with synchronous and normal movement of the muscles controlling the mandible in addition to muscle spasm as etiologic factors. The importance of abnormal tongue movement and habits has been demonstrated. These and the synergistic movement of the external pterygoid muscles can be etiologic factors in indirect trauma of the mandibular articulation. The coronoid process, carrying the insertion fibers of the temporal muscles, also is an important traumatic factor. Pain from cervical tooth erosion can affect the manner of function of masticatory muscles and give rise to traumas. If the diagnostician approaches such disorders with only the temporomandibular joint in mind, he will be incorrect in the location of the area of the indirect traumas in approximately 60 per cent of patients with mandibular articulation disorders. More often, the lateral head pain reported by the patient arises from injury to the fibers of the muscle at their insertion and from the coronoid process.

The evidence which I have compiled indicates that the bulk of temporomandibular cases, of indirect traumatic origin, can be divided into two pathologic categories: (1) those occurring within the joint structure including contusion, osteoarthritis, and occasionally rheumatoid arthritis in this order of frequency, and (2) those occurring periarticularly with functional alterations of the external pterygoid muscles. The two categories may occur solely or concomitantly. The temporomandibular joint is extremely flexible and normally is the victim rather than the active guide of the opening tilt. This joint and the external pterygoid muscle, when injured or strained, create an area of hyperesthesia or oversensitiveness and are capable of producing considerable psychogenic disturbances. The degree and chronicity of the involvement depend upon the nature of the injury to the external pterygoid muscle, probably the superior fasciculus of this muscle. The initial injury can arise from compression by the condyle head, either in an anterior glide, lateral rotation, or during the opening tilt, or to an injury, strain, or fatigue within the external pterygoid muscle. The nature of the problem is different with a posteriorly displaced condyle, which produces more tearing, than with a condyle in an anterior position, which is a compression problem. Any diagnosis of temporomandibular complaints must start at the level of the joint itself, and not at the level of the dental arches. There are other causes of pain in this area, such as constitutional, the external acoustic meatus, fluid collecting in the infratemporal fossa, the coronoid process, and the posterior and insertion fibers of the temporal muscles. Any one of these could he the sole cause for pain in this area. Fig. 6 shows in outline a minimum spectrum of thought in diagnosing these cases. This is a simple, specific technique for diagnosing these joint complaints, for ascertaining the degree of involvement, and for determining independently of the patient's report whether or not therapeutic measures have been successful. While occlusal therapy is still our most effective therapeutic measure, I believe it is apparent that we must use other aids in some of these cases. For example, I have used 2 per cent Novocain as a therapeutic aid and to help differentiate the psychogenic cases. In some, I got a cure unexpectedly, i.e., relief from pain. More recently, I have used hyaluronidase, and Hydrocortone in well-selected cases. I feel that injection therapy can be an important adjunct, but it should not be used empirically. I have presented only the core of a differential diagnostic technique which has been guided by my early dissections. Many phases of this outline can be developed more extensively. I have found this approach to be very satisfactory, and without the confusion attending most discussions I have heard or read. Whenever a seemingly new symptom develops in a patient's temporomandibular joint problem, I have found the solution by thinking as directed in this article, and I have discovered the explanation in normal pathologic or physiologic terminology. I believe this to be an effective, concrete technique for diagnosing temporomandibular and periarticular disturbances.

The etiology, importance, and clinical nature of a mild, subtle swelling of the face was described, and the primary physiologic mandibular articulation as it should be viewed clinically was outlined. This type of facial asymmetry is a clinical manifestation of some injury to part or all of the physiologic mandibular articulation. Further, a fascial pathway from this articulation to the orbit was described, suggesting the possibility that trauma in this area could be the cause of some eye irritation or other injury that could result from the presence of excessive fluid. Further, a potential path for drug application to the posterior part of the orbit of the eye through an oral approach was demonstrated.