Deep dry needling of trigger points located in the lateral pterygoid muscle: Efficacy and safety of treatment for management of myofascial pain and temporomandibular dysfunction
Gonzalez-Perez et al. · Med Oral Patol Oral Cir Bucal · 2015
Evidence Level
STRONGOBJECTIVE
Evaluate whether deep dry needling at trigger points of the lateral pterygoid muscle reduces pain and improves TMJ function compared with pharmacological treatment
WHO
48 patients aged 18-65 years with chronic myofascial pain (>6 months) in the lateral pterygoid muscle
DURATION
3-week treatment with follow-up up to 70 days
POINTS
Trigger points in the lateral pterygoid muscle using sterile 40-mm needles
🔬 Study Design
Dry Needling
n=24
3 weekly deep needling sessions
Pharmacological Control
n=24
Methocarbamol/acetaminophen for 3 weeks
📊 Results in numbers
Reduction of pain at rest (needling)
Reduction of pain at rest (medication)
Improvement in mouth opening
Adverse effects with needling
Adverse effects with medication
Percentage highlights
📊 Outcome Comparison
Pain reduction (VAS 0-10)
TMJ functional improvement
This study showed that dry needling is more effective than medication for treating muscular pain in the jaw. The treatment recorded no adverse effects in the needling group and provided durable improvement in pain and mouth movement.
Article summary
Plain-language narrative summary
Myofascial pain syndrome is a complex disorder of the musculoskeletal system that can affect the orofacial region, particularly the temporomandibular joint (TMJ) and the masticatory muscles. The lateral pterygoid muscle is frequently affected by trigger points, which are hypersensitive areas in the muscle that cause local and referred pain. This randomized controlled trial investigated the efficacy and safety of deep dry needling (DDN) compared with conventional pharmacological treatment for the management of myofascial pain and temporomandibular dysfunction. The study was conducted at the Hospital Universitario Virgen del Rocío in Seville, Spain, between May and October 2013, including 48 patients aged 18 to 65 years who presented with chronic myofascial pain (duration greater than 6 months) localized in the lateral pterygoid muscle.
Participants were randomized into two groups: the test group received deep dry needling (n=24) and the control group received pharmacological treatment with methocarbamol/acetaminophen (n=24). The diagnosis was confirmed using specific clinical criteria of Simons and imaging studies including panoramic radiography and magnetic resonance imaging to rule out other conditions. The treatment protocol consisted of three weekly applications of dry needling in the test group, using sterile stainless steel needles (40 mm long, 0.25 mm gauge) inserted into the trigger points of the lateral pterygoid muscle. The objective was to elicit a local twitch response, considered essential for the therapeutic effect.
The control group received two tablets of methocarbamol (380 mg) and acetaminophen (300 mg) every six hours for three weeks. Assessments were performed at baseline (day 0), at 28 days, and at 70 days after the start of treatment. The main parameters included pain at rest and during chewing using a visual analog scale (VAS), range of mandibular movements (opening, laterality, and protrusion) measured with a Therabite ruler, and TMJ functionality assessed by a 100-point questionnaire. The results demonstrated significant superiority of dry needling across multiple outcomes.
Both groups showed statistically significant pain reduction, but the dry needling group showed better levels of pain reduction both at rest and during chewing. From day 0 to day 70, pain at rest decreased 68% in the dry needling group versus 63% in the control group. Pain associated with chewing decreased 69% and 72%, respectively. Statistically significant differences favored dry needling on days 28 and 70 for both types of pain (p < 0.05).
With respect to mandibular movements, the dry needling group showed significant improvements in maximum opening, lateral movements, and protrusion from day 0 to day 70, with respective increases of 2%, 38%, 29%, and 40%. The control group showed limited improvements only in mouth opening and left lateral movement on day 70. TMJ functionality improved 56% in the dry needling group compared with 35% in the control group. Efficacy assessment by patients and investigators was superior in the dry needling group, with 42% of patients rating the outcome as optimal versus 13% in the control group.
An important safety aspect was demonstrated: no patient in the dry needling group experienced adverse effects, while 41% of the control group reported medication-related side effects, mainly drowsiness. Eight patients in the control group dropped out of the study prematurely due to personal difficulties in keeping scheduled appointments. The clinical implications are significant, suggesting that dry needling of trigger points in the lateral pterygoid muscle offers an effective and safe therapeutic alternative for the management of temporomandibular myofascial pain. The treatment showed sustained benefits up to 8 weeks after termination, with improvement proportional to the initial pain intensity.
The mechanism of action, although not fully understood, appears to be related to the local twitch response obtained during needling, considered essential for the desired therapeutic effect.
Strengths
- 1Randomized controlled design with well-defined groups
- 2Complete absence of adverse events in the dry needling group
- 310-week follow-up allowing assessment of effect durability
- 4Rigorous diagnostic criteria with imaging confirmation
- 5Multiple clinical outcomes systematically assessed
Limitations
- 1Relatively small sample size (n=48)
- 2High dropout rate in the control group (33% of patients)
- 3Follow-up limited to only 10 weeks
- 4Study was not double-blinded due to the nature of the interventions
- 5Conducted at a single center, limiting generalizability of the results
Expert Commentary
Dr. Marcus Yu Bin Pai
MD, PhD · Pain Medicine · Physical Medicine and Rehabilitation · Medical Acupuncture
▸ Clinical Relevance
Temporomandibular dysfunction with a myofascial component in the lateral pterygoid is an underdiagnosed condition in pain services, frequently referred late after frustrated attempts with oral analgesics. This randomized trial positions deep dry needling as a first-line alternative in patients with confirmed chronic myofascial pain—especially in those with contraindications or intolerance to muscle relaxants. The safety profile is directly relevant to decision-making: absence of adverse events in the needling group versus 41% of side effects in the medication group weighs concretely in consultations with patients who drive, operate machinery, or have hepatic restrictions on acetaminophen. The improvement sustained up to ten weeks after the end of treatment suggests a modifying effect on the pain-spasm-pain cycle, and not just symptomatic analgesia, which has a direct impact on the planning of the number of sessions and the periodicity of follow-up.
▸ Notable Findings
The most noteworthy finding is not the reduction of pain at rest—similar between the groups at the end—but rather the superiority of needling in functional outcomes: 38% improvement in right laterality, 29% in left laterality, and 40% in protrusion, against minimal or absent gains in the medication group. This points to a specific biomechanical effect on the trigger point, consistent with the hypothesis of motor endplate dysfunction and focal sarcomere shortening. The 56% improvement in TMJ functionality versus 35% in the control group reflects what is seen in practice: patients who recover functional masticatory capacity, not just symptom reduction. The fact that 42% of patients in the needling group rated the outcome as optimal, versus 13% in the medication group, captures a dimension of overall satisfaction that is frequently overlooked in primary outcomes of clinical trials.
▸ From My Experience
In my musculoskeletal rehabilitation practice, the lateral pterygoid is a muscle that demands technical respect: the intraoral or transfacial approach requires specific supervised training, and I usually reserve it for cases with imaging confirmation and failure of initial conservative approaches. I have observed a perceptible clinical response after the second session—reduction of mechanical pain during chewing and improvement in opening range—with a functional plateau usually between the fourth and sixth sessions. I routinely combine needling with a program of active mandibular mobilization supervised by physical therapy and cervical postural guidance, since TMJ dysfunction rarely exists without a concomitant cervical component. The patient profile that responds best, in my experience, is the one with predominantly myofascial pain, without advanced degenerative arthropathy, and with good adherence to self-care. Cases with severe uncontrolled bruxism tend to recur more rapidly, which reinforces the need for integrated multimodal management.
Full original article
Read the full scientific study
Med Oral Patol Oral Cir Bucal · 2015
DOI: 10.4317/medoral.20384
Access original articleScientific Review
Marcus Yu Bin Pai, MD, PhD
CRM-SP: 158074 | RQE: 65523 · 65524 · 655241
PhD in Health Sciences, University of São Paulo. Board-certified in Pain Medicine, Physical Medicine and Rehabilitation, and Medical Acupuncture. Scientific review and curation of every entry in this library.
Learn more about the author →Medical disclaimer: This content is for educational purposes only and does not replace consultation, diagnosis, or treatment by a qualified professional. Some information may be assisted by artificial intelligence and is subject to inaccuracies. Always consult a physician.
Content reviewed by the medical team at CEIMEC — Integrated Centre for Chinese Medicine Studies, a reference in Medical Acupuncture for over 30 years.
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