Gustaf Hellsing

Arthroscopy of the temporomandibular joint. An autopsy study.

Arthroscopy of the temporomandibular joint (TMJ) is evaluated on an autopsy material. 2 different types of arthroscope--one with a rod-lens system and one with a so-called Selfoc system--were used and compared regarding diagnostic accuracy. On 54 cadavers, it was found that the upper joint compartment may be punctured with accuracy and without damage to vital tissues. Landmarks on the skin facilitating clinical arthroscopy were defined in relation to a guideline from tragus to lateral canthus. A further 49 TMJ specimens were investigated with arthroscopy. The findings are in good agreement with subsequent observations made during dissection. Regarding arthrotic changes, 100% diagnostic accuracy was achieved with both types of arthroscope. Regarding remodelling changes, the diagnostic accuracy was approximately 57%. No significant difference was noticed between the 2 arthroscopes. Photographic documentation with the rod-lens arthroscope was found to be of superior quality.

Arthroscopy of the temporomandibular joint: occurrence and location of osteoarthrosis and synovitis in a patient material.

The superior compartments of 42 temporomandibular joints of 38 patients with longstanding chronic pain and/or functional impairment were examined arthroscopically. Occurrence and location of osteoarthrosis and synovitis were investigated. Osteoarthrosis occurred in 31 joints (74%). In 17 of them more extensive changes were found. Predominant location of osteoarthrosis was the posterior slope of the eminence. The disk was less frequently affected and most commonly in the latero-central part. Synovitis occurred in 22 joints (52%) and was combined with osteoarthrosis in 17 of them. In 20 of them it was of mild and localised nature. The posterior disk attachment was affected in all of them.

Functional adaptation to changes in vertical dimension

The traditional concept of PP stability defies neurophysiologic explanation. Conversely, the hypothesis presented to explain the rapid adaptation of jaw elevator postural tonus to sudden change of vertical dimension is in accordance with research of automotized motor behavior. Furthermore, there is no logical reason to believe that maladaptive reactions develop after prolonged procedures that increase the vertical dimension of occlusion. Rather, Goldspink reports that within a few weeks complete normalization probably occurs. Jaw muscle motor behavior is more dynamic and adaptable to environmental changes than has been believed.

Arthroscopy of the temporomandibular joint: A clinical study

Temporomandibular joint (TMJ) arthroscopy on 30 joints of 26 patients with different signs and symptoms of TMJ arthropathy was evaluated. Local anaesthesia was used and proved efficient. In 27 cases, the superior, and in 3 cases both, compartments were punctured. Successful examination was performed in 26 superior and 3 attempted inferior compartments. Functional impairment following arthroscopy was minor and rarely lasted more than one week. No postoperative bleeding, nerve damage, or infection was observed. Of the 2 systems tested, the rod-lens arthroscope showed superior optical quality.

Arthroscopy of the temporomandibular joint: Examination of 2 patients with suspected disk derangement

2 patients with a history of reciprocal temporomandibular joint (TMJ) clicking were visually examined with arthroscopy of their right side TMJs. Clinical and radiographic examination revealed no signs of arthrosis deformans. One patient with significantly reduced opening ability combined with occasional disappearance of TMJ clicks showed advanced arthrotic changes of cartilage which were not visible radiographically. The other patient with unimpaired function also had a severe arthrotic lesion in the clicking joint. In neither case did the disk appear to be displaced. It is concluded that arthroscopy yields additional information for TMJ diagnosis which cannot be achieved by clinical and radiographic examination alone.

Arthroscopy of the temporomandibular joint. A comparative study of arthroscopic and tomographic findings

Established radiographic criteria of temporomandibular joint osteoarthrosis were evaluated by comparison of arthroscopic and tomographic findings in the superior compartment. 34 joints of 30 patients with long-standing chronic pain and/or functional impairment were investigated according to standardized techniques. Agreement was found between arthroscopy and corrected sagittal tomography regarding diagnosis of osteoarthrosis in all advanced cases. Diagnostic accuracy as regards slight changes was, however, lower. At tomographic examination, the sensitivity was slightly higher than specificity, i.e., pathological changes were more frequently identified than normality. No radiographic sign of osteoarthrosis could be specifically associated with arthroscopic features of osteoarthrosis or synovitis. Predominant location of osteoarthrosis at both arthroscopy and tomography was the posterior slope of the eminence (latero-central part). Osteoarthrosis was more widespread in the fibrocartilage than in the subchondral bone.

Temporomandibular joint disorders: A diagnostic challenge

During the past decade much interest has been focused on disorders of the TMJ. The etiology appears to be multifactorial, with signs and symptoms difficult to evaluate and radiologic investigations insufficient. This review attempted to analyze current diagnostic tools. The recent introduction of various techniques promises optimism for this diagnostic and therapeutic challenge.

Effect of fixed anterior biteplane therapy-a radiographic study

Orthodontic treatment of eight overbite cases with a maxillary fixed lingual arch appliance with anterior biteplane involved a reduction in overbite of 4 to 7 mm between the upper and the lower front teeth and a first molar separation of 2 to 4 mm. After a treatment period of 3.5 to 5 months, occlusal contact between the upper and the lower molars was established. The appliance was then removed, and permanent overbite reduction was secured with an edgewise appliance. With the subtraction technique, 15 temporomandibular joints were radiographically investigated in the retruded position for change of condylar position on the glenoid fossa before and directly after insertion of the appliance, as well as after achieved molar contact. All condyles changed position directly after the bite opening, indicating that pure rotation did not occur. The direction of movement varied not only between subjects but also between the two condyles of each subject. With one exception, none or very small further positional changes occurred during treatment. No imaged signs of hard structure remodeling were observed. It may be concluded that other factors than change of condylar position must be responsible for the therapeutic effect of the bite-opening appliance that has been demonstrated in an earlier study.

Chlorzoxazone and vibrator induced jaw muscle tension

The objective of the study was to clarify some mechanisms behind the relaxing effects of chlorzoxazone. Motor effects induced by vibration of the masseter and digastricus muscles were studied in seven subjects. The response was measured by means of simultaneous recordings of EMG of masseter and digastricus as well as bite force. The measurements were performed before as well as after oral administration of 250, 500 and 1000 mg chlorzoxazone. Since no effect of the medication was seen, it was concluded that the muscle relaxing influences of chlorzoxazone are not effective on segmental levels. Large interindividual differences in responses to vibrations were observed.