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Completed

NCT Number: NCT07820488

Adjunctive Acupuncture for Persistent Myofascial Temporomandibular Disorder Pain

Temporomandibular disorders (TMDs) can cause persistent pain in the jaw muscles and limitations in jaw function. Occlusal splints are commonly used to manage these symptoms, but some patients continue to experience pain despite long-term splint use.

The purpose of this exploratory study was to describe short-term changes after adding acupuncture to ongoing occlusal splint therapy in adults with persistent myofascial TMD pain. The study included 30 adults who had experienced pain in the masseter and/or temporalis muscles for more than 12 months and had used a maxillary full-arch stabilization splint for at least five consecutive years while remaining symptomatic.

All participants continued their occlusal splint therapy and received four 30-minute acupuncture sessions, administered once per week. Assessments were performed before the first acupuncture session and after the fourth session. The assessed outcomes were pain intensity, the amount of pressure required to produce pain in the jaw muscles, maximum mouth opening, and the electrical activity of the masseter and temporalis muscles.

All participants received the same intervention, and there was no control or comparison group. The study was therefore designed to characterize short-term changes within participants rather than to determine whether acupuncture was superior to another treatment or whether it directly caused the observed changes.

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Key information

Conditions

Temporomandibular Disorders (TMD) Craniomandibular Disorders Jaw Diseases Joint Diseases Mandibular Diseases Muscular Diseases Musculoskeletal Diseases Myofascial Pain - Dysfunction Syndrome of TMJ Stomatognathic Diseases Temporomandibular Joint Disorders

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Faculty of Dental Medicine, university of Porto

Porto, Porto District, 4200-393, Portugal

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Age 18 years or older.
  • Ability to understand the study procedures and provide written informed consent.
  • Diagnosis of myalgia according to the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) Axis I.
  • Persistent or recurrent pain in the masseter and/or temporalis muscles for more than 12 months, including pain during the 30 days before enrollment, with muscular pain confirmed by clinical examination.
  • Use of a maxillary full-arch stabilization splint for at least five consecutive years before enrollment.
  • Persistence of temporomandibular disorder-related muscular pain despite ongoing occlusal splint use.

Exclusion criteria

  • History of significant trauma to the temporomandibular joint.
  • Poorly controlled systemic metabolic disease.
  • Active cancer.
  • Pregnancy.
  • Significant neurological disorder.
  • Use of medications affecting neuromuscular function during the 30 days before enrollment.
  • Needle phobia.
  • Inability to comply with the intervention and assessment schedule.

Treatment and study plan

Adjunctive Acupuncture

Procedure

Participants received four acupuncture sessions administered once per week by a practitioner with specific training and experience in acupuncture. Each session lasted 30 minutes. Sterile, single-use stainless-steel needles measuring 0.25 mm × 25 mm were inserted bilaterally at LI4, ST5, ST6, ST7, and ST8. After skin disinfection with 70% alcohol, needles were inserted perpendicularly to a depth of approximately 10-20 mm, adjusted according to the anatomical site and tissue thickness, with stimulation intended to elicit the de qi sensation. Acupuncture was provided as an adjunct to the participants' ongoing maxillary full-arch stabilization splint therapy.

Primary outcomes

  1. Change in Pain Intensity Assessed With the 11-Point Numeric Rating Scale

    Time frame: Baseline and week 5.

    Participants rated their current orofacial pain intensity using an 11-point Numeric Rating Scale ranging from 0 (no pain) to 10 (worst pain imaginable). Change was calculated as the post-intervention score minus the baseline score. Negative change values indicate a reduction in pain intensity.

Secondary outcomes

  1. Change in Pressure Pain Threshold of the Masseter and Temporalis Muscles

    Time frame: Baseline and week 5.

    Pressure pain threshold was measured in kilopascals (kPa) using a digital algometer applied perpendicularly to the skin over the masseter and temporalis muscles. Participants indicated when increasing pressure was first perceived as painful. Measurements were obtained bilaterally for both muscles. Change was calculated as the post-intervention value minus the baseline value. Positive change values indicate an increased pressure pain threshold and reduced pressure pain sensitivity.

  2. Change in Maximum Mouth Opening

    Time frame: Baseline and week 5.

    Maximum mouth opening was measured in millimeters using a calibrated ruler placed between the incisal edges of the anterior teeth. Participants were assessed while seated with the Frankfurt plane parallel to the floor. Change was calculated as the post-intervention value minus the baseline value. Positive change values indicate increased maximum mouth opening.

  3. Change in Surface Electromyographic Root Mean Square Amplitude at Mandibular Rest

    Time frame: Baseline and week 5.

    Surface electromyographic activity was recorded bilaterally from the superficial masseter and anterior temporalis muscles while the mandible was in the postural rest position. Three 5-second recordings were obtained, and the root mean square amplitude was calculated over the interval between 2 and 4 seconds. Change was calculated as the post-intervention value minus the baseline value. Negative change values indicate lower electromyographic amplitude.

  4. Change in Surface Electromyographic Peak Amplitude at Mandibular Rest

    Time frame: Baseline and week 5.

    Surface electromyographic activity was recorded bilaterally from the superficial masseter and anterior temporalis muscles while the mandible was in the postural rest position. Three 5-second recordings were obtained, and peak amplitude was defined as the highest amplitude recorded during the interval between 2 and 4 seconds. Change was calculated as the post-intervention value minus the baseline value. Negative change values indicate lower peak electromyographic amplitude.

  5. Change in Surface Electromyographic Root Mean Square Amplitude During Maximum Intercuspation

    Time frame: Baseline and week 5.

    Surface electromyographic activity was recorded bilaterally from the superficial masseter and anterior temporalis muscles during maximum intercuspation. Parafilm M was positioned bilaterally in the molar region, and participants performed a 5-second maximum voluntary contraction. Three recordings were obtained, and the root mean square amplitude was calculated over the interval between 2 and 4 seconds. Change was calculated as the post-intervention value minus the baseline value.

  6. Change in Surface Electromyographic Peak Amplitude During Maximum Intercuspation

    Time frame: Baseline and week 5.

    Surface electromyographic activity was recorded bilaterally from the superficial masseter and anterior temporalis muscles during maximum intercuspation. Parafilm M was positioned bilaterally in the molar region, and participants performed a 5-second maximum voluntary contraction. Three recordings were obtained, and peak amplitude was defined as the highest amplitude recorded during the interval between 2 and 4 seconds. Change was calculated as the post-intervention value minus the baseline value.

Sponsors and collaborators

Lead sponsor

Universidade do Porto

Other

Registry information

Official study title

Short-Term Clinical and Electromyographic Changes Following Adjunctive Acupuncture in Adults With Persistent Myofascial Temporomandibular Disorder Pain Despite Long-Term Occlusal Splint Use: An Exploratory Single-Arm Pre-Post Study

Important dates

Study start
2025
Primary completion
2026
Study completion
2026
First posted
Sep 15, 2026
Registry last updated
Sep 15, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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