Experimental Pain and Fatigue Induced by Excessive Chewing

Abstract

<jats:title>Abstract</jats:title> <jats:p>Background: The study was aiming to optimize excessive gum chewing as an experimental model to induce jaw muscle pain and fatigue similar to those in painful TMDs with durations that would allow immediate investigations of jaw-motor function. Further, if any sex differences would be detected in the expression of pain. Methods: This randomized, double blinded study included 31 healthy participants of both sexes. A standardized chewing protocol of either 40- or 60-minutes of chewing was used with a wash-out period of one week. Subjective fatigue, pain characteristics and functional measures were assessed. For statistical analyses, Wilcoxon Signed Rank test, Mann–Whitney Rank Sum test and Friedman’s ANOVA with Tukey post-hoc test were used. Results: High subjective fatigue scores that lasted up to 20 minutes after the end of the trial were significantly induced both in the 40- and 60-minute chewing trials (P&lt;0.001*). Significant but mild pain was induced only in the 60-minute trial (P=0.004*) and only in men (P=0.04*). Also, the induced pain area was significantly bigger in the 60-minute trial (P=0.009*). However, this increase in pain and pain area did not last to the first 10-minute follow-up. There were no significant differences neither between the 40- and 60-minute chewing trials, except regarding the pain area (P=0.008*), nor between the sexes. Conclusion: Taken together, excessive chewing in its current form does not seem to be a proper pain experimental model. The model needs further adjustments in order to mimic TMD-pain especially in women and to prolong the pain duration.</jats:p>

Association between Temporomandibular Disorder and Masticatory Muscle Weakness: A Case report

“…This treatment approach may seem counterintuitive because chewing gum is generally regarded as an abnormal habit and a contributing factor of TMDs, and patients are discouraged from preferences that require excessive chewing such as gum or hard food until TMD related symptoms improve [6]. Research on chewing gums, however, reported that chewing gum for 40 to 60 minutes a day was not appropriate to become an experimental model for causing TMD pain [7]. In fact, one study reported that continuous gum chewing can be an effective exercise for the oromandibular function that does not accompany changes in mandibular angle or facial appearance [8].…”