Does Frequency of Temporomandibular Disorders Pain Influence on Physical and Emotional Function?

BACKGROUND: Pain frequency is considered an important aspect of pain chronicity, linked to heightened pain and psychosocial distress. In the International Classification of Orofacial Pain (ICOP), temporomandibular disorders (TMD) are classified as frequent (FR, 1-14 days/month) and highly frequent (HF, ≥ 15 days/month), but whether this is clinically relevant is unknown. OBJECTIVES: This retrospective study aimed to examine differences in FR and HF TMD patients regarding demographics, diagnostics, characteristic pain intensity (CPI) and disability (GCPS), jaw function (JFLS), psychosocial variables (depression, anxiety, pain catastrophizing (PCS) and somatic symptoms) and oral-health-related quality of life (OHIP-5). METHODS: Records of 208 patients with either FR or HF TMD pain (ICOP), were included. All patients had been examined according to the Diagnostic Criteria for TMD (DC/TMD) axis I and axis II. Univariate statistics were used to compare FR and HF TMD, and multivariate statistics to identify variables differentiating HF from FR TMD (p < 0.05). RESULTS: Arthralgia and degenerative joint disease were more common in HF TMD compared to FR (p = 0.004 and p = 0.010). HF TMD had higher CPI (p < 0.001), JFLS (p < 0.001), PCS (p < 0.001) and OHIP-5 (p < 0.001) scores. Higher CPI, GCPS, PCS, JFLS and OHIP-5 distinguished HF from FR TMD patients (p < 0.05). CONCLUSION: HF TMD patients showed increased pain intensity, disability, catastrophizing jaw functional limitations, and reduced quality of life distinguishing them from FR TMD patients. This study is the first to demonstrate the clinical relevance of the ICOP frequency-based classification of TMD, highlighting its importance in the risk assessment and management of these patients.