Functional and psychosocial impact of painful temporomandibular disorder on mandibular function and oral health-related quality of life: a cross-sectional observational study

Background: This study evaluated the association of pain in temporomandibular disorder (TMD) with mandibular function, perceived stress, and oral health-related quality of life (OHRQoL) in adults diagnosed using the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD). It compared these outcomes between individuals with painful TMD (myalgia, arthralgia, or combined) and non-painful TMD (disc displacement or degenerative joint disease), with secondary analyses by sex and age. Methods: A comparative cross-sectional study was conducted with 65 adults diagnosed according to DC/TMD criteria at a university dental clinic in Portugal. Participants were classified as Painful TMD (n = 34) or Non-painful TMD (n = 31). Pain intensity was measured using a Visual Analogue Scale (VAS; 0–10 cm). Mandibular function (Jaw Functional Limitation Scale, JFLS-20), perceived stress (Perceived Stress Scale, PSS-10), and OHRQoL (Oral Health Impact Profile, OHIP-14) were compared between groups using Mann-Whitney U tests. Spearman correlations, rank-biserial effect sizes, and multivariable linear regressions adjusted for sex and age were performed. Results: Participants with painful TMD showed significantly greater mandibular functional limitation (JFLS-20: 1.28 ± 1.14 vs. 0.30 ± 0.61; p < 0.001) and poorer OHRQoL (OHIP-14: 11.71 ± 9.08 vs. 4.81 ± 6.08; p < 0.001). These differences remained significant after adjustment for sex and age (JFLS-20: β = 0.93, p < 0.001; OHIP-14: β = 9.28, p = 0.001). Perceived stress did not differ significantly between groups (PSS-10: p = 0.514). Women and participants >35 years exhibited higher functional and quality-of-life impairments. Conclusions: Painful TMD is associated with greater mandibular dysfunction and poorer OHRQoL compared to non-painful TMD, and these differences remained statistically significant after adjustment for sex and age. Although stress differences were nonsignificant, these findings support the importance of integrating functional and quality-of-life assessments into routine TMD care to identify patients requiring targeted pain management and functional follow-up, adopting interdisciplinary, biopsychosocial treatment strategies.