Immediate Effect of Ultrasound Therapy on Bilateral Masseter Myalgia

Immediate Effect of Ultrasound Therapy on Bilateral Masseter Myalgia: A Randomized Double Blinded Investigational Trial

This study will compare ultrasound 0.4 W/cm^2 and 100% duty cycle versus no ultrasound (placebo) for bilateral masseter myalgia in up to 38 adult women. The dose will be applied for 5 minutes on each side. Both the dose and the starting side will be randomized. Both the subject and ultrasound operator will be blind to the dose. The outcome measures will be pressure pain threshold on both masseter muscles and both temporalis muscles, self reported pain scale (0, no pain to 10, worst pain ever), thermographic temperature of the muscles, and intraoral temperature. These outcome measures will be taken before and after each dose, so three times per subject.

Subjects will receive 5 minutes of ultrasound treatment at 0.4 W/cm^2 and 100% duty cycle on each masseter muscle.

The change in pressure pain threshold from before to after the ultrasound (or placebo) will be averaged over the two masseter muscles, and over the two temporalis muscles.

Immediate. Data taken before and after each dose, so three times in the one session which lasts about one hour to completion..

Self reported pain scale, change from pre- to post-ultrasound dose which lasts about one hour to completion.

The change in self reported pain scale from before to after the ultrasound (or placebo) will be averaged over the two masseter muscles, and over the two temporalis muscles.

The intraoral temperature in the buccal area near the masseter muscle will be recorded before and after the ultrasound

Immediate. Data taken before and after each dose, so three times in the one session which lasts about one hour to completion.

The thermographic temperature of each masseter and each temporalis muscle will be recorded before and after the ultrasound.

Immediate. Data taken before and after each dose, so three times in the one session which lasts about one hour to completion.

Inclusion Criteria: Adult females Bilateral myalgia based on Diagnostic Criteria for TMD (DC-TMD) (Schiffman, et al., 2014) Current pain intensity ≥4 out of 10, (where 0 is no pain and 10 is the worst pain ever) on both sides. Exclusion Criteria: History or diagnosis of systemic musculoskeletal disorders. Rheumatologic diseases (e.g. fibromyalgia, muscular atrophy). Certain conditions such as neoplasms or fractures. Neuropathies or neurological disorders. Currently taking muscle relaxants or analgesics. Any form of physical therapy within the last 60 days.

Schiffman E, Ohrbach R, Truelove E, Look J, Anderson G, Goulet JP, List T, Svensson P, Gonzalez Y, Lobbezoo F, Michelotti A, Brooks SL, Ceusters W, Drangsholt M, Ettlin D, Gaul C, Goldberg LJ, Haythornthwaite JA, Hollender L, Jensen R, John MT, De Laat A, de Leeuw R, Maixner W, van der Meulen M, Murray GM, Nixdorf DR, Palla S, Petersson A, Pionchon P, Smith B, Visscher CM, Zakrzewska J, Dworkin SF; International RDC/TMD Consortium Network, International association for Dental Research; Orofacial Pain Special Interest Group, International Association for the Study of Pain. Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) for Clinical and Research Applications: recommendations of the International RDC/TMD Consortium Network* and Orofacial Pain Special Interest Groupdagger. J Oral Facial Pain Headache. 2014 Winter;28(1):6-27. doi: 10.11607/jop.1151.