Supplementary Material for: Oral Cannabidiol in the Treatment of Myofascial Pain Disorder of the Temporomandibular Region: A Placebo-Controlled Randomized Clinical Trial

Introduction: The efficacy of oral cannabidiol for management of myofascial pain disorder (MPD) of the temporomandibular region remains understudied. Therefore, the purpose of this study was to determine if cannabinoids provide pain relief and improved jaw function in patients with MPD of the temporomandibular region.

Methods: This is a single-center, prospective, double-blind, randomized, placebo-controlled clinical trial. Subjects with pain (≥30 on visual analog scale [VAS]) were screened for MPD as defined by the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD). The primary predictor variable was MPD treatment with random assignment to CBD or placebo (hemp seed oil). The primary outcome variable was jaw pain at 1 month (T1) using a VAS. The secondary outcome variable was pain at 2 months (T2) and 3 months (T3), and jaw function (Jaw Functional Limitation Scale) measured at T1, T2, and T3. Exploratory variable is occurrence of adverse effects from CBD oil versus placebo. Statistical tests included the Chi-squared test, Friedman rank-sum test, and Wilcoxon rank-sum test.

Results: A total of 54 subjects with a median age of 36 (IQR: 30, 51) and 32 (28, 39) years in the CBD oil and placebo groups, respectively (p=0.34 by Wilcoxon rank-sum test). Females represented 28 (80%) and 15 (79%) of the study groups, respectively (p=0.99 by chi-square test). Median VAS pain score in the CBD group was 50 (40, 72), 43 (35, 59), 50 (28, 62), and 45 (25, 62) at T0, T1, T2, and T3, respectively; and the placebo group was 50 (40, 70), 44 (30, 63), 50 (28, 62), and 50 (26, 62) at T0, T1, T2, and T3, respectively. There was no statistically significant difference in VAS pain observed between the groups at any time point (p>0.56 for all by Wilcoxon rank sum test). Within-group improvement in jaw function was seen for both the CBD and placebo groups (p=0.002), but no statistically significant difference was observed between the groups.

Conclusion: Both CBD and hemp seed oil did appear to improve jaw function over time but neither treatment improved pain.