Andreas Dawson1, Bijar Ghafouri, Björn Gerdle, Thomas List, Peter Svensson, Malin Ernberg. 1. *Department of Orofacial Pain and Jaw Function, Faculty of Odontology, Malmö University, Malmö, Sweden Departments of ‡Pain and Rehabilitation Center §Medical and Health Sciences ∥Occupational and Environmental Medicine, Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University ¶Centre of Occupational and Environmental Medicine, Östergötland County Council, Linköping, Sweden #Department of Rehabilitation Medicine, Skåne University Hospital, Lund, Sweden ‡‡Section of Orofacial Pain and Jaw Function, Department of Dental Medicine, Karolinska Institutet, Huddinge, Sweden **Department of Dentistry, Section of Clinical Oral Physiology, Aarhus University, Aarhus, Denmark ††Center for Functionally Integrative Neuroscience (CFIN), MindLab, Aarhus University Hospital, Aarhus, Denmark †Scandinavian Center for Orofacial Neurosciences (SCON).
Abstract
OBJECTIVES: It has been suggested that tooth clenching may be associated with local metabolic changes, and is a risk factor for myofascial temporomandibular disorders (M-TMD). This study investigated the effects of experimental tooth clenching on the levels of 5-HT, glutamate, pyruvate, and lactate, as well as on blood flow and pain intensity, in the masseter muscles of M-TMD patients. METHODS: Fifteen patients with M-TMD and 15 pain-free controls participated. Intramuscular microdialysis was performed to collect 5-HT, glutamate, pyruvate, and lactate and to assess blood flow. Two hours after the insertion of a microdialysis catheter, participants performed a 20-minute repetitive tooth clenching task (50% of maximal voluntary contraction). Pain intensity was measured throughout. RESULTS: A significant effect of group (P<0.01), but not of time, was observed on 5-HT levels and blood flow. No significant effects of time or group occurred on glutamate, pyruvate, or lactate levels. Time and group had significant main effects on pain intensity (P<0.05 and <0.001). No significant correlations were identified between: (1) 5-HT, glutamate, and pain intensity; or between (2) pyruvate, lactate, and blood flow. DISCUSSION: This experimental tooth clenching model increased jaw muscle pain levels in M-TMD patients and evoked low levels of jaw muscle pain in controls. M-TMD patients had significantly higher levels of 5-HT than controls and significantly lower blood flow. These 2 factors may facilitate the release of other algesic substances that may cause pain.
OBJECTIVES: It has been suggested that tooth clenching may be associated with local metabolic changes, and is a risk factor for myofascial temporomandibular disorders (M-TMD). This study investigated the effects of experimental tooth clenching on the levels of 5-HT, glutamate, pyruvate, and lactate, as well as on blood flow and pain intensity, in the masseter muscles of M-TMDpatients. METHODS: Fifteen patients with M-TMD and 15 pain-free controls participated. Intramuscular microdialysis was performed to collect 5-HT, glutamate, pyruvate, and lactate and to assess blood flow. Two hours after the insertion of a microdialysis catheter, participants performed a 20-minute repetitive tooth clenching task (50% of maximal voluntary contraction). Pain intensity was measured throughout. RESULTS: A significant effect of group (P<0.01), but not of time, was observed on 5-HT levels and blood flow. No significant effects of time or group occurred on glutamate, pyruvate, or lactate levels. Time and group had significant main effects on pain intensity (P<0.05 and <0.001). No significant correlations were identified between: (1) 5-HT, glutamate, and pain intensity; or between (2) pyruvate, lactate, and blood flow. DISCUSSION: This experimental tooth clenching model increased jaw muscle pain levels in M-TMDpatients and evoked low levels of jaw muscle pain in controls. M-TMDpatients had significantly higher levels of 5-HT than controls and significantly lower blood flow. These 2 factors may facilitate the release of other algesic substances that may cause pain.
Authors: Sofia Louca Jounger; Nikolaos Christidis; Britt Hedenberg-Magnusson; Thomas List; Peter Svensson; Martin Schalling; Malin Ernberg Journal: PLoS One Date: 2016-12-21 Impact factor: 3.240
Authors: Maria C C Volkweis; Gabriela W Neculqueo; Raquel D S Freitas; Ana P A Dagnino; Guilherme G Fritscher; Tatiana Q Irigaray; Maria M Campos Journal: Sci Rep Date: 2021-05-26 Impact factor: 4.379