The placebo effect, not actual therapeutic action, accounts for most of the treatment effect of acupuncture or dry-needling for masticatory muscle pain.
In this research, a network meta-analysis was performed to examine the outcome of acupuncture and dry-needling as treatments for masticatory muscle pain, and to compare these results with active and inactive placebos. The study gathered randomized controlled trials (published until September 2019). These trials looked at the use of dry-needling, acupuncture, and inactive and active placebos in treating patients with masticatory muscle pain. Outcome variables taken into consideration were the intensity of pain post-treatment, pressure pain threshold and maximum mouth opening.
Both network meta-analysis and direct pairwise meta-analysis showed no significant difference in post-treatment pain intensity and pressure pain threshold between the use of acupuncture or dry-needling and active and inactive placebos. However, patients showed a significant increase in the maximum mouth opening after undergoing dry-needling compared to receiving a placebo. Despite this short-term effect, findings suggested that the majority of the treatment effect for masticatory muscle pain is due to the placebo effect, rather than from the direct therapeutic activities of the acupuncture or dry-needling techniques.
