Associations Between Sleep Disorders and TMD Symptoms in Adult Patients: A Cross-Sectional Study

Background and Objectives Sleep disorders (SDs) negatively affect psychophysical well-being and quality of life and may be associated with temporomandibular disorders (TMDs), which involve pain, limited mandibular mobility, and joint sounds. However, their relationship remains unclear. This study aims to investigate the prevalence of TMDs in patients with SDs. Materials and Methods An observational study was conducted following approval by the Ethics Committee of Vita-Salute San Raffaele University (Gnathology TMDs Protocol, approved on 12 March 2025). One hundred patients with a confirmed diagnosis of sleep disorders (39 females and 61 males; mean age 58.6 ± 18.7 years) were recruited at the Neurology–Sleep Disorders Unit of San Raffaele Hospital “Ville Turro” and the Dentistry Unit of Vita-Salute San Raffaele University in Milan, Italy. Participants were selected according to specific inclusion and exclusion criteria. Data were collected using validated Diagnostic Criteria for Temporomandibular Disorders (TMDs) (DC/TMD) Axis I and II instruments, including the TMD Pain Screener, DC/TMD Symptom Questionnaire, Graded Chronic Pain Scale (GCPS), Jaw Functional Limitation Scale version 8 (JFLS-8), Patient Health Questionnaire version 15 (PHQ-15), and Oral Behaviors Checklist (OBC). Questionnaires were completed in the presence of a dentist and a sleep medicine physician. Descriptive statistics were used to summarize population characteristics. Continuous variables were compared using Student’s t-test or the Wilcoxon rank-sum test, as appropriate, while categorical variables were compared using the Chi-square test or Fisher’s exact test. Statistical significance was set at p less than 0.05. Results Statistical analysis showed the prevalence of a TMD sign or symptom in 38% of subjects with SDs. The most common signs and symptoms reported were: TMJ and/or facial pain (57.89%); TMD-related headache (50%); and joint noises (68.42%). The study also showed that subjects with SDs and almost one TMD sign or symptoms have a significantly higher risk of adopting parafunctional habits, as well as higher chronic pain intensity, with respect to the other ones. The more frequent SDs observed in the TMD sub-group were insomnia, OSAS, and Restless legs syndrome (RLS). Conclusions In conclusion, the results of this study suggest a possible association between SD and TMDs, which require further investigation.