Studies on the reproducibility between days of the silent period of the masticatory muscles.

If the silent period is capable of being a useful tool in the diagnosis and prognosis of the temporomandibular joint dysfunction in adolescents, the silent period elicited methods need to be simple and reproducible.The authors investigated the variable elicited methods of silent period and the variance between days of silent period using the 5 same men. The electromyographic activities in the anterior temporal and masseter muscles during tooth tapping and jaw jerk were recorded bilaterally and the duration and latency of the silent period variance was 3 days. The following results were obtained.The duration and latency of the silent period during tapping and jaw jerk showed significant differences carring out 3 times for 3 days in both muscles. Therefore we think that carrying out a comparison using defferent days and subjects for the absolute value of the silent period provides data which is incorrect.A variance of silent period during the jaw jerk was bigger than the tapping.In regard to the duration of silent period in the tapping, in the temporal muscles it was longer than in the masseter muscles.