Study On The Changes Of The Electromyographic Activities In Atresia During Orthodontic Treatment

Objective:In order to research the influence of the orthodontic treatment on myoelectric activity and provide reference data for the patients’treatments, we compared the myoelectric activities of masseter, temporalis anterior and sternocleidomastoid muscles at different time during the orthodontic treatment in mandibular postural position (MPP) and maximal voluntary clenching (MVC), and also compared the myoelectric activities of these muscles between the atresia and normal patients.Methods:1. Treatment group:all the17patients were atresia.The age range was20-36years old. Test the myoelectric activity of temporalis anterior, masseter and sternocleidomastoid muscles in MPP and MVC at different time during the orthodontic treatments for the patients. Recorded the electromyography.2. Control group (11persons):The age range was19-26years old. Test the myoelectric activity of temporalis anterior, masseter and stemocleidomastoid muscles in MPP and MVC at the beginning of the test. Recorded the electromyography. And the results became a comparison.3. At the beginning of the study, we chose6subjects by using simple random sampling methods, and test the myoelectric activity of these muscles by another doctor, so that we could compare the consistency between operators. Result:1. Before the treatment, the electromyographic activities of the experiment and control groups in MPP had no significant difference (P>0.05), while the average peak potential of experiment group in MVC was lower than that of the control group, but there was no significant difference (P>0.05).2. There was no significant difference in the electromyographic activities of MM, TA and SCM in MPP between males and females. But in MVC, the electromyographic activities of these muscles were different in gender. The average peak potential of these muscles in females was significantly lower than in males (P<0.05).3. The symmetry of the paired muscles was lower in experiment group than in control group.(P<0.05).4. In MVC, after the bite opening, the average peak potential of TA and MM in experiment group was obviously lower than before (P<0.05); and there was no significant difference between the potential of SCM in MVC before and after the bite opening (P>0.05). When the treatment had been almost complete, the electromyographic activities of TA and MM had an increase trend.5. In MPP, after the bite opening, the potential of TA, MM and SCM in experiment group was obviously higher than before (P<0.05); When the treatment was almost completed, the electromyographic activities of these muscles had a reduce trend.Conclusion:1. We need to strengthen the muscle function training, make it tend to normal during the orthodontic treatment in order to reach the harmony of the form and function, reduce the duration of the orthodontic treatment, and maintain the curative effect of orthodontic treatments.2. Because the atresia is the susceptible population of TMD, during the orthodontic treatments we should prevent and control the occurrence and development of the TMD.