Abstract
This article presents the reflections of a clinician who has been involved in the diagnoses and management of temporomandibular disorders (TMDs) for approximately 40 years. It provides an illustration of how our understanding of TMDs has advanced over the years. The author describes how an adverse reaction to a routine restorative procedure led to a study of the articulatory system.
This opinion paper discusses several key points regarding TMD diagnosis and management, distilled through decades of practical experience. TMD is a phrase that encompasses distinct diagnoses; it is not a single condition, and not all TMDs affect the temporomandibular joint (TMJ). The development of sound classification systems for TMD have been an aid to both research into and clinical management of TMD. TMDs are multifactorial and effective management will require a multidisciplinary approach. In the case of a chronic pain TMD patient an understanding of the effects that chronic pain can have on the general wellbeing of the patient is invaluable, and dentists are encouraged to acknowledge and develop such skills. There is an important role for the general dental practitioner in the diagnosis and management of TMD.
Keywords
Introduction
Having joined the Temporomandibular Joint (TMJ) Clinic at the University Dental Hospital of Manchester (UDHM) in 1986, I am pleased to summarise in this article my personal perspective on the evolution of temporomandibular disorder (TMD) diagnosis and management over the past 40 years.
Following my graduation from a British Dental School in 1971, I developed an interest in occlusion within restorative dentistry. My eventual invitation to join the “TMJ Clinic” at the UDHM was precipitated by two formative experiences. The first involved a three-unit bridge I provided for a patient to replace an upper first premolar. By the standards of my undergraduate training, the restoration was a success: it adhered to the (now discredited) Ante’s Law, the shade and morphology were a precise match, and the marginal fit was excellent.
However, the patient never successfully adapted to the bridge. Almost immediately after cementation, she reported persistent pain in her face and sensitivity in the abutment teeth. Even after performing endodontic treatment on those teeth, her symptoms remained.
This distressing outcome, following a procedure I believed was technically sound, revealed a significant gap in my clinical expertise. I realised that restorative success required a deeper understanding of occlusion – a subject not fully explored in my initial training. At the time, major resources like Mike Wise’s excellent book Occlusion and Restorative Dentistry for the General Practitioner had not yet been published, which ultimately led me to pursue advanced postgraduate studies in the USA. 1
The second experience was an embarrassing but enlightening episode involving an Oral & Maxillofacial Surgeon (OMFS) Consultant who ran the TMJ Clinic at the MDH. He had scheduled a patient for invasive surgery to address a severely restricted mouth opening, assuming the cause was intra-articular pathology. However, as the anaesthesia took effect in the operating room, the “pathology” vanished – the patient’s jaw relaxed into a normal range of motion. This dramatic revelation that the restriction was muscular rather than structural underscored the vital importance of distinguishing between functional and joint disorders, further cementing my interest in TMJ.
Later, having completed my postgraduate studies in occlusion, I contacted this same consultant to further my knowledge of TMJ anatomy. He was keen to know what I had learned in the USA; when I mentioned my proficiency in fabricating Michigan splints, he offered me an honorary lectureship. That was in 1986, and 40 years later, I am still there.
My first mentor at the TMJ Clinic wisely noted that we had much to learn together, suggesting I spend my first six months in the university library. This period proved revelatory, as I uncovered a vast body of knowledge that, for various reasons, had simply never been integrated into standard dental school curricula.
A note on terminology: TMJ vs. TMD
Although this piece is titled “Diagnosis and management of temporomandibular
It is difficult to explain why the assumption that all TMDs are rooted in the joint remains so pervasive. While Thomas Annandale’s 1887 paper – the earliest on the subject – initially linked TMD pain to the joint, it is perhaps unfair to lay the blame solely at his feet. 2 More likely, the responsibility lies with those of us who teach the subject. Clearly, our efforts over the last 40 years have not yet been effective enough to displace these entrenched misunderstandings.
The evolution of TMD theories
To understand the management of TMDs, we must first examine the various theories regarding their aetiology. In 1934, James Costen proposed that TMJ neuralgia resulted from pressure on the joint most likely caused by malocclusion – a condition that came to be known as “Costen’s syndrome”. Though now outdated, a search of “Dr Google” will produce some current exponents of this theory that the pain and dysfunction is caused by pressure to the joint. I recall, as an undergraduate, hearing with horror a senior clinician pursuing a line of questioning of a young patient based upon his theory that energetic kissing was the cause of pain in the region of the TMJ.
Other proposed theories of the cause of TMDs include stress, depressive illness, anxiety, hormonal issues, connective tissue disease, genetics, arthritis, malocclusion, poor posture, auto-immune responses, and bruxism. The fundamental truth is that the range of diagnoses that exist within the term TMD are multifactorial and so trying to isolate the single cause misses the clinical reality and certainly reduces the likelihood of achieving a successful management plan for the individual patient.
Classification of TMDs
Arguably the most significant milestone in advancing our understanding of TMDs occurred in 1992 with the publication of the Research Diagnostic Criteria for TMD (RCD/TMD). 3 This represented a major undertaking and, as the title suggests, it was aimed at providing a sound scientific framework for TMD research. This large document comprised listings of many diagnostic categories and subtypes. While this level of detail proved invaluable for research purposes, many clinicians found it to be impractical for routine use in busy clinical TMD settings. However, its importance should not be underestimated as it reduced the tendency to base treatments on diagnoses that were not evidence-based. 2 In 2014, a new Diagnostic Criteria was published by a large group of international experts. 4 This aimed to provide shorter and simpler protocols for TMD, that would be useful not only for research but in the clinical setting. This was not an admission the RDC/TMD had in some way failed in its objectives, because it was always envisaged to be a first step. Similarly, and maybe finally, in 2024, a new diagnostic criterion for TMD is reported. 5 This is the brief diagnostic criterion (bDC/TMD) and is aimed at enabling many more patients suffering from a TMD to be accurately diagnosed in primary care.
When studying the classification of TMD, the recently published Management of painful temporomandibular disorder in adults 6 is a very good place to start. In particular, it divides TMD diagnoses into two broad origins: myogenous (coming from the muscles) and arthrogenous (coming from the joint).
Finally, it is worth noting that the Wilkes’ Classification, which is widely used by surgeons, is a graded classification of TMJ internal derangements rather than a classification of TMD per se.
Management
There have been several very important developments in the care of patients with TMD over the 40 years that I have been treating these patients.
Outdated theory: A single condition affecting the TMJ
As previously noted, patients with TMD were historically grouped under a single diagnostic label. In contrast, current understanding recognises a range of distinct diagnoses under the generic term of TMD. It is also well recognised that patients may present with more than one condition simultaneously. For example, a patient with a clicking TMJ, for whom a diagnosis of disc displacement with reduction has been made may also have significant muscle pain (myalgia) leading to an additional diagnosis of myofascial pain. In this example, the first stage of managing that patient well will be to establish the patient’s primary concern. Often it is not the pathology within the joint.
Outdated theory: A single cause
There is no doubt that TMDs are multifactorial, which is why they usually require multidisciplinary care.
Multifactorial
The move away from looking for a single “cause”, has led to a view that a painful myogenous TMD (myofascial pain) may represent a reduction in the patient’s adaptive capability. This would explain why some patients of the same gender with similar occlusions, parafunctional habits, stressful situations and psychosocial circumstance develop facial muscle myalgia and others do not. On realising this, my surprise was reduced when I remembered that I was used to seeing some patients with poor oral hygiene who did not develop periodontal disease, and others with excellent oral hygiene who did.
Multidisciplinary care
As dentists caring for a patient with a painful TMD, we can develop skills that go beyond our undergraduate taught interventions, such as appropriate occlusal splints. In our everyday work we are used to managing nervous and anxious people; our empathy can be extended into managing patients with the stresses of their everyday life. Initially, I was wary of doing this fearing that I might be straying into an area for which I had no qualification. However, I was encouraged to try to help patients in this way by a dual-qualified Lead Clinician of a TMD Clinic in a major European city: in his experience, due to dentists’ skills in reducing anxiety, they are well placed to help equip patients with various coping strategies that can be called on when they are having a “bad pain day”. This type of help starts when you can make a diagnosis which enables you to tell a patient not only what you think it is, but – also importantly – what it is not. Some patients will need more professional help for the low mood that is associated with their chronic pain, and so referral to their general medical practitioner (GMP) might be appropriate. Over the years, it has never failed to surprise me how grateful a patient can be for the validation you can give for their pain (“it is like you have backache in your face”), and the effect it can have on their quality of life.
In respect of treating their muscle pain, the number of referrals for physiotherapy, warm compresses and the use of self-massage have become significant areas of management. Looking back, I am surprised it took us so long to realise this.
Outdated theory: TMDs only concern Specialist Clinics
When I realised that there was something missing from my undergraduate training, I came to learn that what was absent was the concept of the biomechanical system into which my dentistry was being placed. Further study made me realise that that system (made up of inter-related and inter-dependant parts) was the articulatory system, which is made up of the TMJs, masticatory muscles, and the occlusion. This realisation has not only influenced my restorative treatment planning but also, I believe, my understanding of TMDs.
Dentists who work in primary dental care routinely examine the other two parts of the stomatognathic or masticatory system: namely the teeth and the periodontal systems. Over the years consideration of the third element, the articulatory system, has been not only important in the understanding of TMDs, but also valuable in the provision of complex restoration of the dentition.
The second reason why primary care dentists are ideally placed to help TMD patients is related to timing: they will usually see the persistent pain patients sooner than secondary care clinics.
Current practice: An understanding of chronic or persistent pain
Dentists are well trained in the management of pain – but that is acute pain. GMPs, Rheumatologists, Physiotherapists, Occupational Therapists, the staff of Pain Clinics and many other healthcare professionals would describe a “pain patient” as someone who suffers from chronic or persistent pain. As a result, dentists – including myself – having little or no exposure to this unfortunate group of patients during our training, lack understanding of chronic pain and its consequences. Learning about this has transformed how painful TMD patients can be helped, for both the patient and the practitioner.
Central sensitisation occurs in many patients who have had a persistent pain for over three months. 7 On a cellular level it represents an enhanced function of nociceptive neurons and circuits, resulting in hyper-analgesia. It is well researched and understood in the wider medical field. Those of us who are and have been involved in helping chronic facial pain patients were late in gaining an understanding of the effects of central sensitisation. These effects include:
anxiety
depression or low mood
increased parafunction
impaired social contacts
stress
There was a time when these factors were widely regarded as causes of myofascial pain. While they may act as exacerbating factors, it is now more appropriate to consider them largely as consequences of the condition. There is a multidirectional relationship between pain, anxiety and depression, poor sleep quality, and increased muscle tonicity, all of which commonly coexist in patients with myofascial pain. 8 Once this was understood – and importantly, once patients themselves were helped to understand it – care became more effective for this group of patients who had often felt stigmatised. In my view, this shift has fundamentally transformed the way we manage this unfortunate group of our patients. I feel that we are closer to becoming orofacial physicians instead of dental surgeons.
Conclusion
An interest in TMDs shows a dentist who is not only attentive to the biomechanical environment of the articulatory system in which we employ our restorative skills, but who also demonstrates the kind and caring traits that make up the soft skills that the best health professionals demonstrate.
TMDs can result in pain and/or functional impairment affecting the head and face. Given that this anatomical region houses all five senses and plays a central role in identity, communication and daily function, such symptoms can cause immense distress. Contributing to the alleviation of this burden, helping to improve that situation represents one of the higher callings of our profession.