The Immediate Effect of Occlusal Splint on the Mandibular Movement Velocity of the Temporomandibular Disorder Patients

Background: The effect of the occlusal splint has been studied extensively by using electromyography (EMG) and bite force analysis. Previous report had elucidated the effects of occlusal splint on the velocities of the mandibular movement in non-temporomandibular disorders (TMD) subjects. Aim: To determine the influence of occlusal splint on the velocity of mandibular movement in TMD subjects. Methods: Twenty TMD patients (16 males and 4 females, ranging from 21 to 26 years old) were observed by using Myotronics Kinesiograph K-6 Model for the measurement of jaw motion velocity before and immediately after occlusal splint insertion. Each subject was instructed to open and close the mouth as wide and fast as possible. Ten continuous open-close strokes were recorded and processed to evaluate the following parameters: (1) the maximal opening and closing velocity, (2) the average opening and closing velocity and (3) the maximal terminal velocity 1 mm before tooth contact. Mean velocity of ten consecutive movement strokes was compared with the result by ANOVA. Results: Analysis of data indicated that the maximal and average closing velocities were reduced after occlusal splint insertion (P＜0.01). Neither the opening velocity nor the maximal terminal closing velocity was affected by splint insertion (P＞0.05). Conclusion: Under the condition of this experiment, the velocity of mandibular closing movement phase decreased immediately after occlusal splint wearing in TMD patients.