Analysis of a Joint Degeneration Model and Degradable Craniofacial Screws in the Rabbit Temporomandibular Joint

摘要

To reduce the impact of temporomandibular joint (TMJ) disorders (TMDs), the primary goals are to eliminate pain and restore joint function. However, with the limitations of current treatment options reaching these goals remains elusive. Limitations of current approaches include diagnostic evaluation, missing the early signs of the disease, and recurring pain. There is also difficulty with device fixation, permanent metals implanted, and device life expectancy. To begin addressing some of these limitations and goals, the specific aims of this dissertation focused on the use of altered joint occlusion to gain a better understanding of a TMD model using fibrocartilage, pain, and joint kinematic assessments and testing magnesium as a biodegradable screw in the craniofacial region. From the altered occlusion model, a connection between the compressive properties of TMJ condylar fibrocartilage after 6 weeks of altered loading and changes in histology was observed. Behavioral and anatomical pain assessment results were consistent with an increase in nociceptive signaling, while changes in excitability and action potential waveform were consistent with compensatory changes of TMJ afferents for an overall increase in afferent drive associated with joint degeneration. With the development of the kinematic assessment for the TMJ, repeatable measurements for both translations and movement paths were found for both the incisors and the motion of the condyle relative to the fossa in rabbits. An overall decrease in the range of joint motion was observed at the incisors and in the joint space, with the altered occlusion model. These results suggest a change in joint occlusion, leads to condylar damage, which may contribute to pain associated with at least some forms of TMJ disease. Craniofacial bone remodeling occurred around two magnesium alloy screw types, indicating the promise of using magnesium alloys for craniofacial devices. Due to the essential function of the TMJ for everyday living, the knowledge gained in this dissertation will provide a better understanding of TMDs and improve treatment options.