UBC Theses and Dissertations
Treatment of acute arthrogenous pain in the human temporomandibular joint with an oral orthopaedic applicance Tobias, David Leonardo
The biomechanical events that accompany functional loading of the human mandible are poorly understood. Computer simulations has emerged as an indirect way to demonstrate the principles of jaw mechanics. The modelling of condylar load distributions for various clenching tasks has lead to the observations that deviations in form and osteoarthritic changes as most commmonly found in the central and lateral regions of the articulation reflect habitual compressive loading of the temporomandibular joints. Speculation has existed that compressive stresses as measured during simulated unilateral tooth clenching, offer a functional correlate for regional differences in articular pathology. It has been suggested due to the indirect measuring of the effects of these loads, that well-known progressive deterioration of the discs and articular surfaces are largely brought about by persistent non-working side compression of the temporomandibular joint structures. This in the short term is believed to lead to arthralgia of sufficent magnitude that patients often seek treatment by dental clinicians. In the first study, an existing 3D FEM model of the human mandible, modified to include an opposing oral orthopaedic device, was utilized to test for the effect of two clenching tasks on the compressive stresses measured at the level of the condylar heads when an orthopaedic dental appliance with unilateral occlusal contacts was placed between the teeth. It was found that the level of compressive stress in the contralateral side is twice that of the working side joint. A clinical study was then performed in order to test the hypothesis that in acute articular pathology, the use of an orthopaedic appliance designed to reduce the load to the painful joint can positively influence the resolution of arthrogenous pain in the short term. Specifically, it was proposed that this could be achieved with an appliance designed with unilateral occiusal support. A group of patients diagnosed with unilateral articular pathology were randomized into two treatment groups, one was treated with a conventional flat appliance, the other with unilateral occlusal contacts removed from the side contralateral to the painful joint. In both cases, a VAS was used to assess pain in both joints with and without the mechanical stimulus provided by biting on a force transducer placed between the teeth. Patients were followed for 3 weeks after initial testing. It was found that painful symptoms improved in the range, as measured by the VAS, and in the degree of pain for subjects treated with the unilaterally supported appliance, It was also discovered that the range and magnitude of the bite force increased concomittantly with the reduction in painful symptoms. Collectively the studies suggest that muscle activity is sensitive to differences in occiusal support offered by an intra-oral appliance, and that such a device can be used to modify articular loading and/or to control muscle use in such a way as to speed up the resolution of painful intrarticular symptoms in TMJ patients.
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