Abstract
Mandibular movement and variations in the discharge activity of the opening and closing muscles were determined in 18 healthy men 22-24 years old performing the occ cycle at a frequency of 30, 60 or 90 strokes/min, and the following results were obtained.
1. The prescribed degree of opening at a frequency of 30, 60 or 90 strokes/min during the occ cycle provided practically identical subject populations for statistical analysis, showing hight reproducibility.
2. The subjects were divided into three groups according to the degree of opening; group A showed the greatest degree of opening, being significantly different from group B. As the frequency of the cycle increased, the degree of opening became significantly smaller in group A, whereas it remained largely unchanged in group B and C.
3. The time lag between the discharge activities of the opening and closing muscles became smaller in group A as the frequency of the cycle increased, whereas it remained largely unchanged in group B. Overlapping was seen in the time lag between the end of the discharge of the opening muscle and the onset of the discharge of the closing muscle.
4. All groups showed a similar time lag between the discharge activity of the opening or closing muscle and the mandibular movement, regardless of the cycle frequency.
