NCT06617494 · University of Minnesota
Endogenous Pain Inhibition Deficiency in Chronic TMD Pain
(TMD-CPM)
What this study is about
Temporomandibular disorders (TMDs) involve a range of conditions with varied causes, affecting a large portion of the U.S. population and posing challenges for diagnosis and management, especially in chronic cases. Despite advances in understanding TMD pathophysiology, the role of central sensitization, particularly deficient endogenous pain inhibition, remains unclear.
View original scientific description
Temporomandibular disorders (TMDs) involve a range of conditions with varied causes, affecting a large portion of the U.S. population and posing challenges for diagnosis and management, especially in chronic cases. Despite advances in understanding TMD pathophysiology, the role of central sensitization, particularly deficient endogenous pain inhibition, remains unclear. The conditioned pain modulation (CPM) test, used to assess pain inhibition in chronic TMD pain, has produced inconsistent results due to varying testing parameters. The proposed cross-sectional study will investigate the efficiency of endogenous pain inhibition in individuals with chronic TMD pain compared to controls by applying noxious and non-noxious stimuli to facial and non-facial sites. The findings aim to clarify the impact of weaker pain inhibition over the face, how the conditioning stimulus' painfulness affects inhibition and the relationship between pain inhibition and fluctuations in TMD pain intensity.
Interventions
OTHER
Pain modulation testing
During the visit, noxious heat stimuli will be applied bilaterally to the face and distant body sites as part of conditioned pain modulation (CPM) testing. The test stimuli will be individually tailored to be moderately painful, while the conditioning stimulus will vary in intensity: moderately painful, non-painful, and sham heat. Participants will also record daily TMD pain intensity ratings for seven days before and after the visit.
Primary outcome measures
Conditioned pain modulation (CPM) effect
Time frame: 3.5 hours single in-person visit
The CPM effect is manifested as a reduction of pain intensity evoked by a test stimulus (Ts) presented concurrently or right after a painful conditioning stimulus (Cs) applied to a distant body site.
The relationship between daily pain intensity fluctuation and endogenous pain modulation (EPM) efficiency
Time frame: 14 days: 7 days before and 7 days after the in-person visit
The daily presentation of chronic TMD pain is variable, especially in those presenting with pain that affects their daily activities. This variability could be partially attributed to the varying efficiency of EPM in this patient population.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- To be eligible to participate in this study, an individual must meet all the following criteria:
- Provide informed consent, documented in a signed and dated form.
- Will comply with all study procedures, including daily ratings filling before and after the in-person study visit, and be available for the study duration.
- All participants of both genders between ages 18 to 74 years.
- Cases and controls will be matched for age within ±5 years, and all participants must understand English commands to follow study procedures (e.g., during CPM testing). Pain-free controls:
- Age matching (within ±5 years)
- No previous diagnosis for the most common pain-related TMD as defined in the DC/TMD criteria (myalgia, arthralgia, headache attributed to TMD)
- No significant orofacial pain (jaw pain, TMJ pain) in the past 3 months (""significant"" meaning 5 or more days in any month or any pain during the past month)
- No report of significant pain in the last 3 months elsewhere in the body (""significant"" meaning 5 or more days in any month or any pain during the past month), e.g., low back pain, fibromyalgia, migraine headaches
- Not meeting any of the most common pain-related TMD diagnoses as described in the DC/TMD criteria (myalgia, arthralgia, headache attributed to TMD) upon clinical exam following the DC/TMD protocol Chronic painful TMD cases:
- Primary TMD case criteria: Myalgia (masticatory muscle pain) based on clinical exam following the DC/TMD protocol
- Concurrent arthralgia (TMJ pain) and/or headache attributed to TMD allowed
- Myofascial pain must meet the following criteria:
- Onset \>3 months, occurring \>15 days/month on average for \>3 months
- Minimum of 10 jaw pain episodes since onset, each lasting at least 30 minutes and no less than 2 hours within the day, OR unremitting."
Exclusion criteria
- An individual who meets any of the following criteria will be excluded from participation in this study:
- Traumatic facial injury or surgery on the face/jaw, arms, or hands
- Presence of pain related to dental and periodontal pathology
- Has any of the following medical conditions by self-report:
- Renal failure or dialysis
- Heart disease (examples: uncontrolled arrhythmia or hypertension, cardiomyopathy) or heart failure
- Non-allergic bronchospasm (chronic obstructive pulmonary disease and emphysema)
- Diabetes (type I or II) that is not controlled with medication or diet
- Hyperthyroidism
- Uncontrolled seizures
- Used any injection therapy (e.g., tender or trigger point injections, steroid injections), acupuncture, biofeedback, or TENS for managing facial/jaw pain within 2 weeks before the screening assessment.
- If undergoing botulinum toxin injections in the head and neck area, must be 3 months since the last set of injections, and refrain from this treatment until study participation has ended
- History of major depression or other major psychiatric disorder requiring inpatient hospitalization within the last 6 months before the screening assessment
- History of treatment for drug or alcohol abuse within the last 12 months
- Current pain medication use (e.g., opioids, ibuprofen, acetaminophen) that cannot be stopped \<24 hours before each study visit
- Other conditions/diseases associated with altered pain perception: neurological or development disorders (dementia, autism spectrum disorder), neoplasm, multiple sclerosis, trigeminal neuralgia
- Adults lacking the capacity to provide informed consent for themselves
- Unable to understand instructions for sensory testing in English.
- Thermal threshold for Pain-50 (pre-determined at the beginning of visit 1) is outside the temperature range of 40ºC to 49ºC
- Inability to complete at least four daily ratings between the Informed consent, Pre-visit 1 procedures, and in-person visit 1
- Lack of access to electronic devices with internet connection during the study participation
- Anything that would place the individual at increased risk or preclude the individual's full compliance with study procedures or completion of the study. "
Where
- Minneapolis, Minnesota
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
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Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
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Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Aug 19, 2025 · Source of record for eligibility and locations