Brain scans may unlock secrets of chronic jaw pain

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: Main project * Provide signed and dated informed consent form. * Willing to comply with all study procedures and be available for the duration of study participation. * All participants will be females (biological sex by self-report) between ages 18 to 65 years (inclusive), as this includes the majority of the patient population at risk for chronic TMD pain. * Cases and controls will be matched for age within ±3 years, and all participants must be able to understand commands in English to follow study procedures (e.g., during sensory testing). Pain-free controls * TMD-Pain screener score less than 3 out of 7 (Screener available as part of the DC/TMD) * 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 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 diagnosis as described in the DC/TMD criteria (myalgia, arthralgia, headache attributed to TMD) upon clinical examination following the DC/TMD protocol Chronic painful TMD cases * TMD-pain screener score equal to or greater than 3 * Primary TMD caseness 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 10 jaw pain episodes since onset, each episode lasting at least 30 minutes and no less than 2 hours within the day, OR unremitting * Low-impact TMD pain cases: Graded Chronic Pain Scale (GCPS) grade IIa or lower * High-impact TMD pain cases: GCPS grade IIb or greater Inclusion criteria: Patients in MRI Optimization group * Be age 18-65 (inclusive) * Provide a signed and dated informed consent form. * Be willing to comply with all study procedures and be available for the duration of study participation. * Be able to understand commands in English to follow study procedures. Exclusion Criteria: Main project * Traumatic facial injury or surgery on the face/jaw, arms or hands * Presence of pain related to dental or periodontal pathology * Currently undergoing active orthodontic treatment * Pregnant or nursing * 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 (i.e. tender or trigger point injections, steroid injections), acupuncture, biofeedback, or TENS for the management of facial pain within 2 weeks prior to the screening assessment * If undergoing botulinum toxin injections in the head and neck areas, must be 3 months since last set of injections and refrain from this treatment until study has ended * History of major depression or other major psychiatric disorder requiring hospitalization within the last 6 months prior to the screening assessments * 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 prior to each study visit * Other conditions/diseases associated with altered pain perception: neurological or developmental disorders (dementia, autism spectrum disorder), neoplasm, multiple sclerosis, trigeminal neuralgia * MRA contraindications including claustrophobia * GCPS grade assigned at Visit 1 that does not match grade from screening GCPS (low-, high-impact pain) and it is not possible to assign the potential participant to the correct final group, due to the latter having met their recruitment quota * Strictly left-handedness by self-report * Thermal threshold for Pain-50 (determined at Visit 1) is outside the temperature range of 40-49 degrees Celsius * Lack of access to electronic device with internet connection during the study * Inability or unwillingness to receive daily text messages during the study * Inability to complete at least four daily ratings between the Informed consent, Pre- visit 1 procedures and in-person visit 1 * Anything that would place the individual at increased risk or preclude the individual's full compliance with study procedures or completion of the study. Exclusion criteria: MRI Optimization group Pregnant or nursing; * MRI contraindications including claustrophobia; * Adults lacking capacity to provide informed consent for themselves; * Unable to understand instructions for sensory testing in English; * Anything that would place the individual at increased risk or preclude the individual's full compliance with study procedures or completion of the study.