Purpose: This study was designed to evaluate the comparison between the subjective and the objective evaluation of pain control effect in masticatory muscle pain depending on time and dose change. Methods: The patients were recruited to this study and diagnosed according to the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). Experimental group were divided into three groups; saline injection group (n=10), morphine 1.5 mg injection group (n=10), and morphine 3.0 mg

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... on group (n=10). Evaluation list was the subjective pain evaluation (visual analogue scale, McGill pain questionnaire) and the objective pain evaluation (pressure pain threshold [PPT], pressure pain tolerance [PTO]). The subjective and the objective pain evaluation were performed at the times of just before injection, 10 minutes, 30 minutes, 1 hour, 24 hours, and 48 hours after injection. Then, data were statistically analyzed. Results: The results were as follows: 1) There is no statistically significant difference between the results of the subjective and the objective pain evaluation with regard to the shortterm (within 1 hour) analgesic effect of morphine sulfate. 2) However, after 1 hour of injection, while the subjective pain evaluation score still decreased, the objective pain evaluation didn't show significant changes in PPT and PTO (1 hour, p<0.05; 24 hours, p<0.01; 48 hours, p<0.001). 3) In comparison to changes in the dose, the McGill pain questionnaire was the most statistically effective method among the subjective pain evaluations (1.5 mg, p<0.05; 3 mg, p<0.01). Conclusions: Therefore, it was revealed that the subjective pain evaluation was more effective to evaluate long-term pain control, and that the McGill pain questionnaire could be an effective way to evaluate pain control depending on dose changes. It requires further investigations with time and dose extension.