Evaluation of Therapeutic Effects Using the Limitation of Daily Functions Questionnaire in Patients with Temporomandibular Disorders

Aims: This study evaluated the pain-related limitations in daily functions before and after treatment in patients with temporomandibular disorders by using the limitations in daily functions-temporomandibular disorders questionnaire (LDF-TMDQ). Methods: The patients received a treatment protocol comprising jaw exercise, counseling, and information regarding behavioral changes. The mouth-opening ranges with and without pain, pain intensity and chewing difficulty (both rated on the 100-mm pain visual analog scale), and LDF-TMDQ scores (based on a five-point numerical rating scale) were measured before (baseline) and 4 weeks after treatment in 90 patients with temporomandibular disorders. The paired t-test was used to analyze therapy-induced changes at a 5% significance level. The relationship between improvements in LDF-TMDQ scores and improvements in other parameters was analyzed by structural equation modeling. Results: The mouth-opening ranges with and without pains were significantly greater (P<0.001) and pain intensity and chewing difficulty were significantly lower (P<0.001) after treatment. The total LDF-TMDQ score was also significantly lower after 4 weeks of treatment (P<0.001). Structural equation modeling showed that improvements in pain intensity and chewing difficulty directly influenced the improvements in LDF-TMDQ scores. Conclusion: The LDF-TMDQ is suitable for evaluating the therapeutic effects of temporomandibular disorders because changes in the scores were proportional to therapy-induced improvements in mouth-opening range, pain intensity, and chewing difficulty.