This study found significant differences in two out of three pain tolerance level tests - but not pain threshold tests - between the Middle Eastern and Swedish cultures and between genders. These differences were more pronounced between Middle Eastern and Swedish men than between Middle Eastern and Swedish women. Gender differences were more pronounced within the Swedish than the Middle Eastern culture. These findings indicate that culture and gender influence pain experience.

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.

Background: Dopaminergic pathways could be involved in the pathophysiology of myofascial temporomandibular disorders (M-TMD). This study investigated plasma levels of dopamine and serotonin (5-HT) in patients with M-TMD and in healthy subjects. Methods: Fifteen patients with M-TMD and 15 age-and sex-matched healthy subjects participated. The patients had received an M-TMD diagnosis according to the Research Diagnostic Criteria for TMD. Perceived mental stress, pain intensity (0-100-mm visual analogue scale), and pressure pain thresholds (PPT, kPa) over the masseter muscles were assessed; a venous blood sample was taken.