Gender Differences in Influence of Clenching Task on Masticatory Muscles

Objectives: The objective of this study was to determine the effect of sustained voluntary clenching on the development of pain in the masticatory system and the differences between females and males. Methods: Sixteen healthy subjects (eight females and eight males, 27.4±3.0 years old) without masticatory muscle pain participated in this study. Pain intensity level, maximal voluntary bite force, and pressure pain threshold were measured before, one, two, three, and seven days after an experimentally sustained submaximal clenching task. Results: In male subjects, there were no statistically significant changes in all measurements. In female subjects, on the other hand, pain intensity level was significantly higher one day after the clenching task (P<0.05). Maximal voluntary bite force was significantly lower one day after the task (P<0.05). Pressure pain thresholds for the anterior temporalis muscle and lateral capsule of the temporomandibular joint were significantly lower two days after the task (P<0.05). Pressure pain threshold for the deep masseter was significantly lower one day after the task (P<0.05). Pressure pain threshold for the superficial masseter did not change during the period of the study. Conclusions: The present study has shown that post-exercise masticatory muscle pain could be elicited by the repeated submaximal clenching in the healthy female subjects. Moreover, as for female subjects, it was suggested that the pattern of responses of the stomatognathic system to the clenching task could differ according to the measurement sites.