Association between Stress at Work and Temporomandibular Disorders: A Systematic Review

Table 1

Main descriptive features of selected studies ().

Author, year, country	Sample size (final)	Group 1 ()	Group 2 ()	Group 3 ()	Group 4 ()	Group 5 ()	Stress: diagnostic tools, validation	TMD: diagnostic tools, validation	Results	Conclusion
Rantala et al., 2003, Finland	1339	Employees of a Finnish Broadcasting Company with low perceived stress (1020/76%)	Employees of a Finnish Broadcasting Company with high perceived stress (316/24%)				Occupational Stress Questionnaire (OSQ); it is not possible to check the validity of the stress scale.	TMD painless symptoms scale; it was not possible to evaluate the diagnosis validity.	High perceived stress group (50 TMJ-related painless symptoms out of 316); Low perceived stress group (75 TMJ-related painless symptoms out of 1020) (chi-square test; )	There was an association between stress and TMJ symptoms.
Nishiyama et al., 2012, Japan	2203	Electronic industry workers without TMD (1841/84%)	Electronic industry workers with TMD (362/16%)				Items 5–8 for psychosocial factors, including stress; variable is not validated.	Four-item questionnaire screening for patients with TMD-related symptoms (TRS); validated diagnosis.	Stress level and TMD were not associated after logistic regression analysis. No odds ratio was presented for the association between stress level and TMD.	There was no association between stress level and TMD.
Emodi Perelman et al., 2015, Israel	140	General occupation group (48/34%)	Dentists (44/32%)	High-tech workers (48/34%)			Self-reported stress at work; variable is not validated.	Full axis I exam and diagnosis according to the RDC/TMD for myofascial pain; validated diagnosis.	Higher stress at work (chi-square test; ) and myofascial pain (chi-square test; ) for the high-tech and dentist groups compared with the general occupational group.	High-tech workers and dentists were more prone to have stress and TMD.
Saruhanoğlu et al., 2016, Turkey	124	Workers from call centers with low stress (14/11%)	Workers from call centers with medium stress (33/27%)	Workers from call centers with high stress (77/62%)			The stress level of the job; variable is not validated.	Questionnaire from the RDC/TMD, axis 2. The diagnosis is validated.	Frequency of gradual mouth opening (chi-square test; ), TMJ pain (chi-square test; ), and TMJ noise (chi-square test; ) was similar between the stress group levels (chi-square tests).	There was no relation between TMD signs and symptoms and stress in call center employees.
Martins et al., 2016, Brazil	104	Industrial workers with less stress (98/94%)	Industrial workers with more stress (6/6%)				Social Readjustment Rating Scale (SRRS); variable is validated.	Fonseca Anamnesis Index; outcome is validated.	There were 34 workers with TMD out of 98 with less stress and 3 workers with TMD among 6 with high stress levels (Fisher exact test, ).	There was no association between stress and TMD.
Amorim and Jorge et al., 2016, Portugal	93	Violinists least anxious/stressed (46/49%)	Violinists most anxious/stressed (47/51%)				Kenny Music Performance Anxiety Inventory for anxiety and psychological distress; variable is validated.	Fonseca Anamnestic Questionnaire; the outcome is validated.	Music performance anxiety was associated with TMD scores (; 95% CI 2.51–15.33) in the final logistic regression model.	Anxiety and distress were associated with TMD.
Amalina et al., 2018, Indonesia	92	Nurses without TMD (37/40%)	Nurses with TMD (55/60%)				Expanded Nursing Stress Scale (ENSS); variable is validated.	ID-TMD questionnaire, from RDC/TMD; the outcome is validated.	There was no association between TMD and the scores of ENSS: death and dying (Mann–Whitney test; ); conflict with physicians (independent -test; ); inadequate preparation (Mann–Whitney test; ); problems with peers (Mann–Whitney test; ); problems with supervisors (independent -test; ); workload (independent -test; ).	TMD was not associated with work stress among nurses in a type C Indonesian private hospital.
Gayathri et al., 2018, India	153	Software companies and IT professionals without stress (46/30%)	Software companies and IT professionals with stress (107/70%)				A self-administered online questionnaire for general stress symptoms; variable is not validated.	Self-admin. online questionnaire for TMD signs/symptom; outcome is not validated.	Stress level and TMD (Pearson’s chi-square test; ); there was no information on the frequencies of TMD between the groups.	There was an association between stress and TMD.
Han et al., 2018, South Korea	1612	Full-time female workers with low stress (1049/65%)	Full-time female workers with high stress (563/35%)				Self-reported stress; the variable is not validated.	TMD screening questions according to American Academy of Orofacial Pain (AAOP) and RDC/TMD; the outcome is validated.	There were 108 workers with TMD out of 1049 with less stress and 99 workers with TMD among 563 with high stress levels (chi-square test, ).	There was an association between high stress and TMD among female workers.
Van Selms et al., 2019, Netherlands	515	Amateur/semiprofessional musicians for whom loading of the masticatory system is not required (209/40%)	Amateur/semiprofessional vocalists (306/60%)				A single question about the overall amount of stress experienced during the last 30 days (NRS 0-10); variable is not validated.	Symptom Questionnaire (SQ) of the DC/TMD; validated diagnosis.	No association in the final multiple regression model for both TMD pain and TMJ sounds. No odds ratios were presented for the association between stress level and TMD and TMJ sounds.	Stress level was not associated with both TMD pain and TMJ sounds.
Tay et al., 2019, Singapore	2043	Asian military personnel without TMD (1301/64%)	Asian military personnel with TMD (742/36%)				Stress subscale of DASS-21; variable is validated.	Symptom Questionnaire (SQ) of the DC/TMD; outcome is validated.	The mean values of DASS-21 stress subscale scores were 1.95 () and 3.29 () among those without and with TMD, respectively (Mann–Whitney test; ).	There was an association between stress and TMD.
Van Selms et al., 2020, Netherlands	1461	Control: other instrumentalists (208/15%)	Woodwind (371/25%)	Brass (300/20%)	Upper strings instrumentalists (276/19%)	Vocalists (306/21%)	Single question: “how much stress did you experience in daily life during the last 30 days?”; Variable is not validated.	Symptom Questionnaire (SQ) of DC/TMD; the outcome is validated.	No association in the final multiple regression model for TMD pain. There is an association between TMJ sounds and stress (OR 1.09; 95% CI 1.02-1.16; ).	There was an association between TMJ sounds and performance stress.