Conceptualising TMD symptom burden in youths: Symptom duration, frequency, intensity and interference.

OBJECTIVE: This study aimed to conceptualise Temporomandibular disorder (TMD) symptom burden and severity and explored their interrelationships with somatic symptoms and psychological distress.

METHODS: Participants were recruited from a local polytechnic. The quintessential five TMD symptoms (5Ts) of the Diagnostic Criteria for TMDs (DC/TMD) were appraised and extended to evaluate the duration, frequency, intensity and interference of discrete TMD symptoms. Global TMD severity (GS) was computed by totaling the points for all TMD symptoms and dimensions. TMD (TS) and somatic symptom (SS) burden were assessed based on the Somatic Symptoms Scale-8, while psychological distress was measured with the Depression, Anxiety and Stress Scales-21. Statistical analyses were performed using Kruskal-Wallis/Dunn tests and Spearman's correlation (α = .05).

RESULT: Of the 366 eligible participants (mean age 19.1 ± 2.3 years), 51.4% were 5Ts-negative and 48.6% were 5Ts-positive. Among the 5Ts-positive individuals, 25.3%/64.0% were 'bothered a little' whereas 4.5%/10.7% were 'bothered a lot' by TMD pain/headache. Correspondingly, 32.6%/12.4%/5.1% were 'bothered a little' while 2.8%/2.8%/1.1% were 'bothered a lot' by TMJ sounds/closed/open locking. TS burden was moderate-to-strongly correlated to aggregate symptom duration, frequency, intensity, interference, GS and SS burden (rs  = .50-.88). While TS burden and GS were weakly associated with psychological distress (rs  = .18-.36), SS burden was moderately related to depression, anxiety and stress (rs  = .47-.53).

CONCLUSIONS: TS burden can serve as a proxy for global TMD severity and may be more meaningful than the mere presence of TMD symptoms in clinical and research settings.