Mandibular movement function before and after anterior repositioning occlusal device treatment for temporomandibular disorders assessed using an ultrasonic facebow.

STATEMENT OF PROBLEM: Information relating to the use of the Jaw Motion Analyzer (JMA) ultrasonic facebow to evaluate the efficiency of an anterior repositioning occlusal device (AROD) is lacking. PURPOSE: The purpose of this clinical study was to use an ultrasonic facebow to make a preliminary analysis of and explore mandibular movement function. MATERIAL AND METHODS: Temporomandibular disorders were treated with AROD for 3 months, and an ultrasonic facebow was used to accurately record changes in the condylar position and the mandibular border movement tracing of patients before and after AROD treatment. Finally, the changes and characteristics of the mandibular border movement tracing and the 3-dimensional position of the condyle process were compared and analyzed statistically. A comparison of parameter differences between groups, t test analysis, and variance chi-squared test and 1-way ANOVA were performed (alpha=.05). RESULTS: Before treatment, the difference in maximum mouth opening (MMO) between the control and experimental groups was statistically significantly different (P<.05). No statistically significant difference (P>.05) in MMO was found between the control group and the experimental group after treatment. However, a statistically significant difference (P<.05) was found between the experimental group before and after treatment. CONCLUSIONS: After AROD treatment, a new balanced relationship was generated between the facial muscles, the temporomandibular joint, and occlusal states, thus resulting in an improvement in the coordinated position and motion function of the condyle. The JMA ultrasonic facebow was found to be a reliable instrument that can accurately record dynamic movements of the temporomandibular joint.