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Bilateral Variation of the Silent Period and Isotonic and Isometric Activity of Jaw Closing Muscles

Asja Čelebić
Melita Valentić-Peruzović
Ivo Baučić
Jasmina Stipetić
Iva Alajbeg
Davor Illeš

Sažetak

The aim of this study was: 1. To measure latency and duration of the silent period elicited in an open-close-clench cycle in individuals with all teeth and normal occlusion. 2. To compare the latency and duration of a silent period between the different elevator muscles examined and the symmetry of the reflex responses. 3. To analyze isotonic and isometric muscle activity in open-close-clench cycles and to compare it to the maximum voluntary myoelectric activity. Silent periods were registered and measured in 62 individuals with normal occlusion on the EMGA-1 apparatus. Ten registrations of an open-close-clench cycle was made for each participant to elicit silent periods. Signals from the right and left anterior temporal and left and right masseter muscles were recorded by surface electromyography during 240-300 ms. Silent periods had a latency of 12.5-12.9 ms after the occlusal contact and had only a single short inhibitory pause with complete inhibition of motoneurons. The duration of the silent period was 20.1-21.1 ms. There were no statistically significant differences (p>0.05) of the silent period latency and duration between the examined muscles and the left and the right side. Isotonic muscle activity was equal to isometric muscle activity for each muscle in open-close-clench cycles. The mean isotonic muscle activity was spontaneously constant between open-close-clench cycles and was approximately 60% to 70% of the mean muscle activity during maximum voluntary clencing. The reflex was considered oligosynaptic. The reflex was fully symmetrical and of equal latency and duration between the examined muscles. Stimulation of the primary mechanoreceptor afferents in periodontal ligament by tensile forces generated between occlusal tables of opposing teeth and/or vibration of the unique teeth contact (normal occlusion) and consequent stimulation of mechanoreceptors in temporomandibular joint, tendons or muscles by vibration could be responsible for the reflex.

Ključne riječi

silent period; symmetry; normal occlusion; jaw closing muscles; open-close-clench cycle; isotonic and isometric activity

Hrčak ID:

10353

URI

https://hrcak.srce.hr/10353

Datum izdavanja:

15.12.2002.

Podaci na drugim jezicima: hrvatski

Posjeta: 1.908 *