Myofascial pain dysfunction syndrome (MPDS) is the most common form of temporomandibular disorders. Because of the multifactorial nature of the problem, its management is still not definite. This randomized clinical trial aimed to assess the efficacy of transcutaneous electrical nerve stimulation over dry needling for management of such condition.

Myofascial pain syndrome (MPS) is a prevalent affliction among individuals experiencing musculoskeletal pain issues. This condition is characterized by pain originating from the muscle and surrounding fascia. Patients typically exhibit localized pain in a confined region or referred pain with diverse patterns.

Additionally, physical examinations may reveal trigger points on the affected muscles. MPS can be categorized into acute and chronic forms. Acute MPS often resolves spontaneously or with uncomplicated treatments. However, chronic MPS typically has a poorer prognosis, and symptoms may persist for six months or more.

Dry needling involves the insertion of a solid filiform needle into a trigger point without the administration of any substance. Various theories have been put forth to explain the mechanisms by which dry needling alleviates pain . These include the "gate control" theory, modulation of endogenous opioids such as B-endorphin, encephalins, and dynorphins, disruption of central sensitization through activation of Aβ fibers resulting in inhibition of synaptic transmission between Aβ and C fibers and cells of the spinal cord dorsal horn due to their slower impulse conduction, and even placebo effects have been suggested . When a needle is inserted into a trigger point, it may elicit a local twitch response. This reflexive contraction of the trigger point can also facilitate physiological changes, including the reduction of spontaneous electrical activity and the concentration of inflammatory and nociceptive chemicals, ultimately resulting in the relaxation of the trigger point.

Transcutaneous electrical nerve stimulation (TENS) is considered to be a highly secure and cost-effective modality for managing both chronic and acute pain. As per the gate control theory, TENS employs low voltage electrical pulses that are applied to the central nervous system. The modulation of pain perception induced by TENS is attributed to the recruitment of Aβ afferent fibers in the posterior horn of the spinal cord, which prevents the activation of pain conducted in thin fiber. Electrical stimulation effectively inhibits the transmission of painful impulses through the spinal cord and stimulates the release of endogenous opioids by the brain. Its safe, noninvasive, inexpensive and effective method of providing analgesia with reduced potential adverse effects compared to other treatment modalities.

In this research, we aim to evaluate TENS is a suitable treatment for MPDS patients, which would eliminate the need for another treatment modality. The expected benefit in this study is to find the best treatment for MPDS reducing pain, muscle stiffness and limited mouth opening.

Inclusion Criteria:

1. Patients complaining of pain in muscles of mastication lasting for three months or more.
2. Presence of trigger points in the temporalis, masseter or lateral pterygoid muscle identified by clinical examination and palpation.
3. Average pain severity of at least 4 on a 10-point scale
4. Pain in pre-auricular area, or in the ear during rest or function

Exclusion Criteria:

1. No previous tempro-mandibular joint (TMJ) surgical intervention
2. Patients with neurological disorders, coagulopathy, vascular disease autoimmune disease (systemic lupus, rheumatoid arthritis), fibromyalgia
3. Pregnancy
4. Current opioid use
5. Intake of analgesics, muscle relaxant, anti-inflammatory medications such as NSAID's and benzodiazepines,
6. Patients with severe trauma or infections in TMJ
7. Tempro-mandibular dysfunction (TMD) with joint origin (any type of internal derangement)

lack of research ethics committee approval of secondary use of IPD