抄録
Electromyographic studies have been conducted on the time factors of the silent periods that occur during chin tapping with a view to utilizing these factors as criteria for prosthetic treatment.
In the present study, the authors examined the relationship between the time factors of such silent periods and the activity of temporal muscles, masseter muscles, and bite force in normal subjects.
The findings are as follows:
1. The time factors of the chin tap silent periods varied greatly depending upon subjects.
2. At a time when the bite force of each subject reached the maximum, there was a great difference in their muscle activity, ranging from 40 to 190μv.
3. Any significant difference was not observed in the relations between the time factors of the chin tap silent periods and muscle activity.
4. The relations between the time factors of the chin tap silent periods and bite force showed highly significant differences with respect to latency (L), duration (D) and L+D. As the bite force decreased, L shortened while D and L+D lengthened.
5. Patients with temporomandibular joint (TMJ) dysfunction have a weak bite force. However, it remains to be seen whether changes in the time factors of the silent period in the people examined are comparable to those in the patients with TMJ dysfunction.
