Sleep duration and inflammatory mediator levels associated with long-term prognosis in temporomandibular disorders

Abstract

Background: Sleep disturbance is a systemic symptom and at the same time a major modulating factor of temporomandibular disorders (TMD). Inflammation is known as a underlying mechanism involved in both poor sleep and increased pain.

Objective: The relationship between long-term clinical characteristics and hematologic biomarkers of hypothalamic-pituitary-adrenal axis activity and inflammation in TMD patients according to sleep duration was investigated to verify the possible role of sleep disturbance and systemic inflammation in TMD.

Materials and methods: Inflammatory and stress mediator levels of venous blood samples were investigated in 63 female TMD patients along with comorbidity levels including stress, somatization, autonomic symptoms and sleep quality based on structured questionnaires. Differences in long-term clinical characteristics and hematologic variables following conservative treatment were analysed according to total sleep time as normal, short and long sleep groups. Also, clinical and hematologic indices related to favourable treatment response were sought out.

Results: Significantly less patients in the long sleep group reported pain on voluntary mandibular movement (p = .042) while depression (p = .043) and somatization levels (p = .002) were significantly higher in the short sleep group. Norepinephrine levels of the long sleep group were significantly lower than other groups. Decrease in pain intensity with treatment was smallest in the short sleep group. Erythrocyte sedimentation rate was associated with significant pain improvement at 3 months post-treatment and interleukin-1β, -4, and -8 levels could predict favourable treatment response.

Conclusion: Short sleep is associated with more comorbidities and unfavourable long-term treatment response in TMD which may be mediated by systemic inflammation. Effective management of sleep is necessary for successful TMD management.

Keywords: comorbidity; inflammation; prognosis; sleep duration; stress; temporomandibular disorders.