Prevalence of Self-Reported Temporomandibular Disorder Symptoms in Patients With Obstructive Sleep Apnea Based on the Fonseca Anamnestic Index: A Cross-Sectional Multicentric Study.

Background Obstructive sleep apnea (OSA) is a common sleep-related breathing disorder characterized by recurrent upper airway obstruction and fragmented sleep. Temporomandibular disorder (TMD) comprises musculoskeletal conditions affecting the temporomandibular joint and masticatory muscles, often presenting with pain and functional limitations. Both conditions share clinical features such as sleep disturbance and musculoskeletal discomfort, suggesting a possible relationship. However, the prevalence of TMD among patients with OSA and its association with clinical characteristics remains insufficiently explored. Objectives The main objective of this study is to determine the prevalence of symptoms suggestive of TMD among patients with severe OSA using the Fonseca Anamnestic Index (FAI) and to evaluate the association between TMD severity and selected demographic and clinical variables, including age, gender, body mass index (BMI), and OSA-related symptoms. Methods This cross-sectional, multicentric, observational study was conducted from August 2024 to August 2025 at the Department of Prosthodontics and Crown & Bridge, Sardar Patel Postgraduate Institute of Dental and Medical Sciences, Lucknow, India, in collaboration with the Departments of Prosthodontics and Crown & Bridge and Respiratory Medicine at King George's Medical University, Lucknow, India. A total of 110 adults aged 18-60 years with polysomnography-confirmed severe OSA (apnea-hypopnea index ≥ 30 events/hour) were enrolled. Patients with prior OSA or TMD treatment, temporomandibular joint surgery or fracture, malocclusion, orthodontic history, recent analgesic use, neurological disorders, or unwillingness to provide consent were excluded. Symptoms suggestive of TMD were assessed using the FAI. Demographic, clinical, and OSA-related variables were recorded. Descriptive statistics and association analyses were performed to evaluate relationships between TMD severity and clinical parameters. Results The study population had a mean age of 48.28 ± 8.80 years, with a predominance of male participants. More than three-fourths of the participants were overweight or obese, and hypertension was the most frequently reported comorbidity. Symptoms suggestive of TMD were identified in 52.7% of patients, with mild TMD being the most prevalent category. No statistically significant associations were observed between TMD severity and age, gender, or BMI. Among OSA-related symptoms, excessive daytime sleepiness demonstrated a statistically significant association with TMD severity (p < 0.05), whereas snoring, witnessed apneas, morning headache, and non-restorative sleep did not show significant associations. Conclusion A relatively high prevalence of symptoms suggestive of TMD was observed among patients with severe OSA. TMD severity showed no significant association with most demographic or anthropometric variables. Although excessive daytime sleepiness was associated with TMD severity, this finding should be interpreted cautiously, given the cross-sectional design. These results represent descriptive observations, and further comparative and longitudinal studies are required to clarify the relationship between OSA-related symptoms and TMD.