The Impact of Acute National Stress on Awake Bruxism Behaviour Among Young Adults-An Ecological Momentary Assessment Study.

Background: Awake bruxism (AB) is characterised by repetitive jaw muscle activity during wakefulness and is influenced by various stressors. Objective To investigate the effect of national stress (war) on AB muscle behaviours in young adults, the study was planned as a repeated cross-sectional study.

Methods: Two groups were compared: one during peaceful times (no-national stress group, NoNS; n = 106, 63% female, age 25.4 ± 2.9 years) and one during wartime (an acute national stress group, AcuteNS; n = 82, 77% female, age 28.3 ± 3.3 years). AB behaviours were assessed through a single-point self-report and ecological momentary assessment using a dedicated smartphone application that recorded the frequencies of relaxed muscles, clenching, teeth contact, bracing and teeth grinding. The AcuteNS group additionally completed questionnaires on anxiety and depression, perceived stress, stress coping, ability to bounce back from stressful events, adjustment disorder and medication use.

Results: AcuteNS group exhibited a lower frequency of relaxed muscle behaviour compared to the NoNS group (50.51 ± 29.76 vs. 63.04 ± 27.8, respectively, p < 0.005). Within the AcuteNS group, 68% of individuals were identified as having adjustment disorder. Subjects with adjustment disorder showed a lower frequency of relaxed behaviour and higher frequencies of clenching and teeth grinding than subjects without the disorder. A higher ability to bounce back from a stressful event was associated with an increased frequency of relaxed muscle behaviour, while AB presence and psychotropic medication use were associated with a reduced frequency of relaxed muscle behaviour (linear regression, R = 0.229).

Conclusion: Subjects' ability to bounce back or recover from stress is an important predictor of relaxed masticatory muscle behaviour during acute national stress.