Objectives: The aim of this study was to estimate and compare the short-term therapeutic effect on myogenous pain in temporomandibular (TMD) patients receiving Thai herbal compress (THC) or warm placebo compress (PC).

Methods: Using a placebo-controlled, double-blind, randomized clinical trial, the investigators enrolled a sample composed of subjects with myogenic TMD pain (M-TMD-P) who underwent pain treatment with THC or PC. The predictor variable was treatment group (THC or PC). The outcome variable was 1-month improvement of M-TMD-P, recorded as visual analogue scale (VAS) of pain intensity experienced over the past week, characteristic pain intensity (CPI) scores, pain-related disability scores (PDS) and pain-free maximal jaw opening. Other variables were demographic and diagnostic. Descriptive and bivariate statistics were computed. Statistical significance was set at p≤0.05, single-tailed test of hypothesis.

Results: The sample was composed of 31 subjects (n=16 in THC group). Both THC and PC were linked to the significantly decreased average VAS scores, CPI and PDS within the same group. Pain-free maximum mouth opening was significantly improved in the THC group only (p=0.028). However, these improved variables were not significantly different between THC and PC.

Conclusions: In the setting of M-TMD-P, THC had the only superior benefit on pain-free maximum mouth opening over conventional PC. M-TMD-P patients with limited jaw opening should be treated with THC. The authors cannot comment on the efficacy of THC in comparison to other pain treatment methods, e.g. analgesics or physiotherapy.