title: Association between stress, sleep quality and temporomandibular joint dysfunction: simulated Mars mission.
abstract: OBJECTIVE
  The aim of this study was to test the association between quality of sleep and stress in individuals with TMD (temporomandibular joint dysfunction) in simulated Mars mission.
  
  
  METHODS
  The 24 healthy crew members were recruited. The physiological measures of systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate (HR) were recorded. The Symptom Checklist-90-revised was used which was based on nine dimensions of psychological functioning. The Multidimensional Pain Inventory was pain severity, social and physical activities, affective distress, social support, and feelings of life control. The Pittsburgh Sleep Quality Index was used to measure the number of hours spent in bed and during asleep, frequency and reasons for awakening, and difficulty returning to sleep after awakening. The orofacial pain questionnaire was applied to measure pain experience using descriptors from the McGill Pain Questionnaire. Salivary cortisol and melatonin were measured.
  
  
  RESULTS
  The 15 crew members reported temporomandibular joint pain after 6 days of mission. On dental examination, 5 crew members reported simple muscle pain (SM) and other 10 crew members with TMD. The TMD group endorsed more affective descriptors of their pain experience. Compared to the TMD group, the SM group also reported significantly poorer sleep duration. The TMD group reported nonsignificantly more daytime dysfunction than the control. Higher levels of salivary cortisol and salivary melatonin were reported in the TMD group as compared to other group.
  
  
  CONCLUSIONS
  This study concludes that both quality of sleep and stress levels due to extreme condition (simulated Mars mission) were associated with TMD in simulated Mars mission.
authors.affiliation: President, Simulated Microgravity and Human Body, JBR Institute of Health Education Research & Technology, KSI, South Carolina, USA.
authors.forename: Balwant
authors.initials: B
authors.lastname: Rai
authors.forename: Jasdeep
authors.initials: J
authors.lastname: Kaur
keywords: Mars mission; Simulated; Sleep; Stress; Temporomandibular joint dysfunction