Randomized, double-blind study comparing percutaneous electrolysis and dry needling for the management of temporomandibular myofascial pain

Myofascial pain syndrome (MPS) of the temporomandibular joint is a complex disorder that affects the masticatory muscles, causing pain and functional limitation. The lateral pterygoid muscle is frequently involved, presenting trigger points that generate local and referred pain. This randomized, double-blind, controlled study compared two minimally invasive techniques for the treatment of MPS: percutaneous electrolysis (PNE) and deep dry needling (DDN), versus a placebo procedure. Sixty patients diagnosed with MPS in the lateral pterygoid muscle, with pain for at least 6 months and limited mouth opening (<40 mm), were randomized into three groups of 20 participants each.

The PNE group received needling with application of low-intensity galvanic current (2 mA for 3 seconds), the DDN group received deep needling without introduction of substances, and the control group received superficial pressure without needle penetration. Treatments were performed once a week for three consecutive weeks, with assessments on days 28, 42, and 70 after treatment. The results demonstrated that both active techniques were significantly superior to placebo in reducing pain at rest and during mastication, as well as in improving maximum mouth opening. The PNE group showed earlier improvement, with significant pain reduction by day 28, while the DDN group presented consistent improvement throughout the follow-up period.

Pain at rest decreased from 6.0 to 1.5 in the PNE group and from 6.0 to 2.0 in the DDN group, remaining stable through day 70. Mouth opening improved from 34.5 mm to 40 mm in the PNE group and from 34 mm to 37 mm in the DDN group. TMJ functionality, assessed by a 100-point questionnaire, showed significant improvement in both active groups compared to placebo. Adverse events were minimal, with only one self-limited hematoma reported in the PNE group.

Tolerance to treatment was excellent in all groups, and the subjective evaluation of efficacy was superior in the PNE and DDN groups. The clinical implications are important, as both techniques offer safe and effective alternatives for treating temporomandibular MPS, with PNE having the advantage of faster action, possibly due to the combined effect of mechanical and electrical stimulation. The study has limitations such as the relatively small sample size, difficulty in complete blinding in invasive procedures, and exclusive focus on the lateral pterygoid muscle, when there is often involvement of multiple masticatory muscles.