Biomedical subjects
Publications and source records attributed to G T Clark.
This article reviews the literature on the effectiveness of physical medicine procedures for treatment of temporomandibular disorders (TMD). Brief descriptions of some commonly used dental appliances, and pharmacological and surgical treatment methods are provided.
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These guidelines include the usual and customary treatment approaches recommended for each of the diagnostic categories described in a previous article on the examination and diagnosis of temporomandibular disorders. The current article describes when it is appropriate to use initial therapy, behavior modification therapy, pharmacotherapy, occlusal appliances, physical therapy, and surgical treatment for temporomandibular disorders. The physical therapy procedures described include various exercises as well as pain-relief techniques such as vapocoolant spray, massage, electrical stimulation of muscles and nerves, ultrasound, and trigger-point injections. Pharmacotherapy using muscle relaxant, nonsteroidal anti-inflammatory, tricyclic antidepressant, and narcotic pain medications are also discussed. Occlusal stabilization and repositioning appliances are reviewed as well. Finally, the broad indications for arthroscopic surgery, open surgery, and steroid injections are described.
Ten males sustained maximal voluntary contractions (MVC) of the jaw elevators. Unilateral bite force and electromyographic (EMG) activity were recorded from the right masseter and temporalis. The experiment comprised three endurance trials, and each trial consisted of two sustained 100% MVC clenching tasks. Between the two tasks, the subjects took a randomly assigned rest of either 30, 120 or 300 s. Immediately after each task, they performed an additional brief 100% MVC to check for contractile failure. EMGs were taken from the beginning and end of each sustained 100% MVC and used to determine and compare the EMG centre frequency. The difference in endurance times between the first and second clenchings was greatest for the 30-s rest and progressively decreased as the rest period increased. The beginning EMG centre frequency was significantly greater than the end for each clenching. These findings strongly support the proposal that even though the jaw elevators are resistant to a contractile element failure, a contraction-induced pain is produced, which limits a sustained jaw-closing effort. Recovery from this effort pain is related to the post-contraction blood flow.
We have examined the potential to provide long-term or even permanent wound coverage in a mouse model of a 30% total body surface area burn using skin allografts. Treatment of the recipient mouse with rabbit anti-mouse thymocyte serum (ATS) followed by donor bone marrow infusion induces a state of specific unresponsiveness to the skin allograft without the need for chronic immunosuppression. Specifically, a B6AF1 mouse receives a burn on Day -2 relative to grafting, ATS on Day -1, and Day +2, a skin allograft from a C3H/He mouse on Day 0, and infusion of C3H/He donor bone marrow on Day +6. We studied three groups of burned mice: Group I, allograft control (n = 5); Group II, allograft plus ATS (n = 12); and Group III, allograft plus ATS and bone marrow infusion (n = 15). Mean graft survival was compared using a one-way analysis of variance and a Student-Newman-Keuls post hoc test. There was no statistical difference in animal mortality among any of the three groups, and there was no evidence of infectious morbidity. Mean skin allograft survival was as follows: Group I, 9 days; Group II, 29 days; and Group III, 66 days (P less than 0.05 vs Group I and II). Nine animals in Group III had intact hair bearing grafts at 90 days when the study was terminated. This study suggests the potential use of induced specific unresponsiveness to skin allografts for wound coverage in thermal injury without use of chronic immunosuppression. In our animal study this was accomplished without increased mortality or apparent infectious morbidity.
Ten normal male volunteers performed six maximum voluntary isometric jaw-closing muscle contractions within an 80-minute experimental period. Each individual contraction was sustained until maximum pain tolerance was reached. Before and one, two, three, and seven days after the experiment, the following measures were made: (1) superficial masseter and anterior temporalis muscle tenderness (pain threshold), (2) jaw movement (opening and lateral excursion), and (3) current pain level for the right and left sides of the jaw. In this study, measures of current jaw pain, muscle pain threshold, maximum active opening, and maximum lateral excursions showed no significant post-experimental changes. These results challenge the idea that sustained isometric clenching in healthy male subjects could be used as a model for chronic or even subacute muscle pain, as has been suggested by previous investigators.
Obstructive sleep apnea (OSA) is a syndrome in which the airflow created from breathing ceases through the upper airway although diaphragm movement continues. Resulting complications include severe daytime sleepiness, morning headaches, loud snoring, and disturbed nighttime sleep. Patients affected with OSA are frequently hypertensive and can have dangerous cardiac arrhythmias. The diagnosis of OSA requires an all-night polysomnographic recording; neither snoring nor other subjective complaints constitute adequate criteria for treatment. The treatment objective for OSA is to maintain airway patency. A potential treatment discussed here is temporary advancement of the mandible or tongue during sleep with the use of dental appliances.
Do patients with temporomandibular disorders (TMD) have significant psychosocial problems? Research efforts have sought to determine if these problems exist, and if so, how they influence treatment outcome. Even when psychosocial factors do influence treatment outcome, identifying them by formal psychological tests can be time consuming and costly. Dentists' impressions of the psychological status of these patients were tested to determine if they are an effective method for screening psychological factors thought to influence treatment outcome. The results suggested that a screening procedure based on dentists' impressions from an initial examination do not adequately identify psychological problems in patients with TMD.
These guidelines propose performance criteria for the history and examination of patients with temporomandibular (TM) disorders. Pertinent diagnostic subcategories are identified, and the comprehensive history and review of systems are described. The examination procedures include documentation of temporomandibular and craniocervical range of motion, TM joint sounds, and the recording of muscle and joint tenderness. The TM disorders addressed include muscle problems such as myalgia, protective splinting or trismus, spasm, myositis, dyskinesia, muscle contracture, hypertrophy, and bruxism. Temporomandibular joint disorders addressed include disk-condyle incoordination, restricted condyle translation, open condyle dislocation, arthralgia, osteoarthritis, polyarthritis, and traumatic joint injury. Disorders of mandibular mobility such as ankylosis, adhesions, fibrosis, skeletal obstruction, and hypermobility are also described. Finally, disorders of maxillomandibular growth, including masticatory muscle hypertrophy, atrophy, neoplasia, maxillomandibular hypoplasia, condylar agenesis, maxillomandibular hyperplasia, and condyle hypertrophy are described.
Plasma norepinephrine and epinephrine levels were monitored to determine possible alterations of the sympathetic nervous system caused by hypertonic fluid administration. Iv infusion (3.5 ml/kg, 1 min) of 7.5% NaCl/6% Hespan transiently increased both plasma norepinephrine and epinephrine levels to 197 +/- 28% and 220 +/- 30% of control, respectively, at 1 min. These increases were no longer significant 5 or 15 min following infusion. A brief hypotension was also observed immediately following hypertonic fluid administration. Thus, prolonged sympathetic activation does not occur following hypertonic fluid infusion in normovolemic conscious rats.
The effect of sustained isometric contraction on surface electromyograph (EMG) and force signals derived from these muscles was examined. Premolar-molar region force was measured with a small unilaterally positioned force transducer. Subjects produced and sustained 25, 50, 75 and 100 per cent isometric force levels, and measurements were made at the beginning and end of these efforts. There was no significant change in the resulting EMG/force ratio at any of the force levels. The EMG signal did exhibit a significant shift in its frequency both as the force level increased and during the sustained effort. Neuromuscular fatigue, when defined as a change in the EMG/force ratio, was not demonstrated even though there was a consistent change in the frequency of the EMG signal.
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The effect of a sustained isometric retrusive contraction on maximum voluntary retrusive force levels was measured in normal jaw function. Surface electromyographic recordings of the suprahyoids, masseter and posterior temporalis were taken and force was measured with a force transducer. Subjects sustained isometric force at the 25, 50, 75 and 100 per cent level, and measurements made before, during and after these sustained isometric tasks. There was no change in the brief maximum voluntary contraction levels of the retruder muscles during or after such tasks, which suggests a lack of contractile or electrical failure in these muscles. Pain intolerance, rather than demonstrable neuromuscular fatigue, was the limiting factor for sustained submaximal or even maximal contraction effort.
Results gathered by examining 40 patients with temporomandibular disorders and 40 matched controls for craniocervical dysfunction showed that high scores were more frequent for patients with temporomandibular disorders. Results indicated that these patients should be screened routinely for craniocervical problems.
This presentation has reviewed and discussed the various temporomandibular musculoskeletal disorders with which patients present. Also, a step-by-step sequence of treatment has been presented. Following this escalating sequence of conservative yet appropriate therapy will provide a logical plan of treatment for painful temporomandibular disorders and the majority of patients should be treated successfully (Fig. 30).
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