Temporomandibular disorders: the 2020 National Academies report and the DC/TMD criteria the report says every dentist should be able to use

What it says#

The National Academies of Sciences, Engineering, and Medicine put an 18-member committee on temporomandibular disorders at the request of the National Institute of Dental and Craniofacial Research and the NIH Office of the Director, and released the result in March 2020. The committee's expertise list is the first thing that tells you where the report is going: public health, pain medicine, patient advocacy, physical therapy, dentistry, self-management, oral and maxillofacial surgery, internal medicine, endocrinology, rheumatology, law, nursing, psychiatry and communications.

The framing is a set, not a disease. TMDs are described as more than 30 health disorders associated with both the temporomandibular joints and the muscles and tissues of the jaw, ranging from an occasional click to severe chronic pain across the orofacial region, and often co-occurring with headache, fibromyalgia, back pain and irritable bowel syndrome. The committee's own definition is broad: a set of diseases and disorders related to alterations in the structure, function or physiology of the masticatory system that may be associated with other systemic and comorbid medical conditions. It adopts a biopsychosocial model and says plainly that there is no one treatment or one care pathway, that one size does not fit all.

On prevalence the report is careful. National prevalence is hard to estimate because most data rest on self-reported symptoms rather than examiner-verified classification; the figure it cites is that one analysis of 2018 data found an estimated 4.8 percent of U.S. adults, an estimated 11.2 to 12.4 million adults in 2018, had pain in the region of the TMJ that could be related to TMDs. It adds that orofacial pain symptoms may or may not be related to TMDs.

The patient testimony section is the part a practice owner should read first. More than 110 individuals testified at the public workshop or submitted written comment, and the committee grouped what they said into lack of coordinated care and abandonment, over-treatment and harmful treatment, impact on quality of life, expense, difficulty identifying qualified clinicians, and comorbidities. Under over-treatment, the report records that many patients had endured multiple TMD-related surgeries, in some cases more than 20, often with no resolution or worsening symptoms, and that others had received removable oral appliances, orthodontic correction, replacement of teeth, or some combination. Under identifying clinicians, it records that misleading advertising, in which clinicians claim to be experts without the experience or evidence-based practices, further complicates access.

Eleven recommendations follow. The first four build and fund a National Collaborative Research Consortium for TMDs. Recommendation 5 asks INfORM, the ADA, the American Academy of Orofacial Pain and The TMJ Association, with family medicine, internal medicine and rheumatology organizations, to develop diagnostic, screening and risk stratification tools including a list of high-risk red-flag symptoms for primary care clinicians and dentists. Recommendation 6 asks pain organizations to convene stakeholders and develop evidence-based consensus clinical practice guidelines for dentists and primary care clinicians covering diagnosis, initial treatment and referral. Recommendation 7 goes to the ADA, insurers and CMS on coverage. Recommendation 8 asks for Centers of Excellence for TMDs and Orofacial Pain. Recommendations 9 and 10 go to schools, licensing examinations and the Commission on Dental Accreditation, and ask the ADA's National Commission on Recognition of Dental Specialties and Certifying Boards to recognize orofacial pain as a dental specialty. Recommendation 11 is on awareness and stigma.

The diagnostic protocol the report assumes is the DC/TMD, published in 2014 by Schiffman and colleagues for the International RDC/TMD Consortium Network and the IASP Orofacial Pain Special Interest Group. It is dual-axis. Axis I is physical: a six-item TMD Pain Screener with sensitivity and specificity of 0.95 or better, a Symptom Questionnaire, and a specified clinical examination. Its validated pain diagnoses are myalgia, arthralgia and headache attributed to TMD, with sensitivity of 0.86 or better and specificity of 0.98 or better, and inter-examiner reliability of kappa 0.85 or better. Myalgia is subdivided into local myalgia, myofascial pain and myofascial pain with referral, separated by palpating at 1 kg for 5 seconds rather than 2. For intra-articular disorders the honesty is the point: only disc displacement without reduction with limited opening has acceptable clinical accuracy, at sensitivity 0.80 and specificity 0.97, while disc displacement with reduction, disc displacement without reduction without limited opening and degenerative joint disease are screening procedures that require CT or MRI to confirm. Axis II is psychosocial and behavioral: five screening instruments totaling 41 questions, being the Graded Chronic Pain Scale, the PHQ-4, a pain drawing, the eight-item Jaw Functional Limitation Scale and the Oral Behaviors Checklist, with a comprehensive 81-question set behind them.

Who it applies to#

Anyone with jaw pain, jaw noise, locking or limited opening, at any age, and the clinicians they reach first, who are usually general dentists and primary care physicians. The report's Box S-1 names general dentists, primary care and internal medicine clinicians, pain specialists and oral and maxillofacial surgeons and asks all of them to stay current, give patients evidence-based information, and build relationships across professions for coordinated care.

It does not apply as a rule. A National Academies consensus report is advice; nothing in it binds a licensee, a payer or a board. Its recommendations are addressed to organizations, not to individual practices, and the guidelines it calls for in Recommendation 6 are the document a general dentist would actually follow. That document was still being called for, not cited, when this entry was checked.

The DC/TMD has its own limits. Its intra-articular criteria are explicitly for screening, not diagnosis, outside the one validated subtype, and its accuracy figures come from the Validation Project sample of 705 participants, 614 cases and 91 controls, not from general practice.

What changed#

Against the RDC/TMD of 1992, the DC/TMD changed the names and the evidence behind them. Myofascial pain became myalgia with three subtypes; myofascial pain with limited opening was eliminated; headache attributed to TMD was added as a diagnosis and written into the beta version of ICHD-3; disc displacement with reduction with intermittent locking and TMJ subluxation were added; osteoarthritis and osteoarthrosis became subclasses of degenerative joint disease. The examination gained the criterion that matters most at the chair: familiar pain, meaning the pain produced by a provocation test must replicate the patient's own complaint.

Against common practice, the 2020 report changes the posture rather than the technique. It does not tell you what to do; it says that the evidence base for matching a specific treatment to a specific diagnosis is not yet fully developed, that patients have been harmed by treatments given anyway, and that the profession should stop treating a multifactorial chronic pain condition as a dental repair problem.

Where the source is#

The report is free at the National Academies Press. The link under the title opens the catalog page, where the full 410-page PDF can be downloaded at no cost and every chapter can be read online; the Summary chapter linked in the downloads carries all 11 recommendations in full and is about 16 pages. The suggested citation and the DOI, 10.17226/25652, are in the front matter. The DC/TMD itself is in the Journal of Oral & Facial Pain and Headache 2014;28(1):6-27, free in full text in PubMed Central, with a shorter executive summary for general dentists in JADA 2016;147(6):438-445. The instruments, examination specifications and translations are distributed by INfORM, the successor to the International RDC/TMD Consortium Network, which describes the DC/TMD tools as living documents whose current versions are kept on that page.