Changes in pain intensity and oral health-related quality of life in patients with temporomandibular disorders during stabilization splint therapy--a pilot study.

The aim of the study was to evaluate changes in pain intensity and self-perceived quality of life in patients with temporomandibular disorders (TMD) during stabilization splint therapy. The hypothesis was that the clinical subtype of TMD, depending on whether pain is of muscular or temporomandibular joint origin, and pain chronicity (acute vs. chronic pain) differently affect treatment response. Thirty patients were included and treated with a stabilization splint in a 6-month clinical trial. Treatment outcomes included pain-free maximal mouth opening (MO), assisted maximal MO, path of MO, asymmetry in lateral excursions, spontaneous pain intensity (visual analog scale, VAS), and self-perceived quality of life (Oral Health Impact Profile, OHIP-14). Overall, VAS and OHIP-14 scores changed significantly over time (VAS: F = 80.85, p < 0.001; OHIP-14: F = 34.78, p < 0.001). After 6 months, changes in pain intensity did not differ significantly between myofascial pain (MP) and disc displacement (DD) groups (F = 0.497, p = 0.685, effect size = 0.018), or between acute pain (AP) and chronic pain (CP) patients (F = 1.856, p = 0.144, effect size = 0.064). Changes in self-perceived quality of life did not differ significantly between MP and DD groups (F = 0.213, p = 0.847, effect size = 0.008), or between AP and CP patients (F = 0.816, p = 0.489, effect size = 0.029). Linear regression analysis was used to assess the contribution of each predictor variable to the explanation of the OHIP summary score variance. Results showed pain reduction (coefficient = 0.303; 95% CI: 0.120 to 0.485) and MO increase (coefficient = 0.149; 95% CI: 0.037 to 0.260) to be independent predictors of the OHIP-14 summary score changes (R2 = 0.453), whereas other variables did not affect treatment outcome as assessed by OHIP-14. In conclusion, during 6-month stabilization splint therapy, significant changes in VAS and OHIP-14 summary scores were found. However, there were no significant differences in improvement rates between subjects with acute and chronic pain. Furthermore, no significant differences in improvement rates were found depending on whether pain was of muscular or temporomandibular joint origin.