A common misperception, which tends to be perpetuated by usage in popular media, is that the term “TMJ” represents a distinct, well-defined disorder and that all patients who have “TMJ” are the same or very similar. Within the dental profession that misperception is gradually being understood as such. However, most dentists continue to lack a clear understanding of how patients with temporomandibular disorders (TMD) actually do differ.
Temporomandibular disorders occur as a continuum, from, at one end, relatively minor disturbances of masticatory muscle function (without involvement of the temporomandibular joints) to major structural and functional disturbances of the TM joints at the other end. In addition to the muscles of mastication, there can often be an involvement of other muscles of the head and neck, as well. Across this continuum, the indications for treatment can also vary a great deal, from no treatment at all at the one end, to surgery of the TM joints and subsequent orthopedic rehabilitation of both joint and muscle function, and perhaps the dental occlusion at the other end.
To assure optimum outcomes, appropriate treatment should be based on clearly defined treatment objectives that are consistent with a biologically-specific diagnosis in each patient. Generic “TMJ” treatment, without understanding the actual nature of the underlying problem, is never appropriate. As an example, “let’s try a splint and see if that helps”. When such an approach doesn’t “help”, there may be puzzlement as to why. Therefore, before any treatment is begun, a biologically-specific diagnosis is necessary to determine where on that wide continuum a particular patient’s problem falls.
For dentists who choose not to treat these patients, the process is relatively straight-forward. Once the TMD problem has been identified by means of screening (see “Screening for TMDs in Dental Practice”), all TMD patients will be referred. The process of differential diagnosis then falls to the person who will provide treatment.
For the dentist who chooses to treat some TMD patients but who also recognizes that it may be more appropriate to refer the more difficult ones, doing a preliminary triage of the patient is essential to draw a line between the easier and the more complex TMDs. A decision as to which patients to treat must be based on not only understanding the relative complexity of each patient’s problem, but also on an objective personal assessment of one’s knowledge, skill, and experience, which can only be made by each dentist individually. Before deciding to undertake a full history and examination to determine the biologically-specific diagnosis, some key clinical findings from a screening history and exam will prove helpful in deciding which patients require a more comprehensive work up, prior to undertaking treatment, and which patients should perhaps be referred to a colleague with more knowledge and experience.
The following classification scheme is relatively simple and is intended to compliment the screening process, aiding the dentist in deciding which patients might be treated in their office and which ones should perhaps be referred. The patient types in this classification scheme represent only approximate profiles. As mentioned earlier, TMD patients present along a continuum, without clear lines of demarcation.
Following a screening history and a screening examination, a tentative diagnosis, based on these seven types, can usually be made. A determination regarding which patients you might choose to treat, i.e. the potential complexity of treatment, can only be made after the patient type has been determined.
As suggested earlier, attempting to treat patients using generic approaches is not recommended. When more advanced conditions exist, these can have a potential to worsen in response to certain ill-advised generic treatment approaches. It is recommended that you recognize your personal limits of understanding and only treat patients within your level of knowledge and skill.
• Patient Type 1 — Masticatory Muscle Disorder
• Patient Type 2 — Capsular and Attachment Tissue Disorders (Joint Sprain)
• Patient Type 3a — Disc Displacement With Reduction
• Patient Type 3b — Disc Displacement With Reduction
• Patient Type 3a versus Type 3b
• The Critical Zone
• Patient Type 4 — Disc Catching With Reduction
• Patient Type 4 — Variability
• Patient Type 5 — Disc Displacement Without Reduction (Joint Locking)
• Patient Type 6 — Arthropathies (Degenerative Joint Disease, Osteoarthritis, Osteoarthrosis)
• Patient Type 7 — Aberration in Form
General Statements, Types 1 – 6
• Historical and clinical assessment is essential when determining patient type. At a minimum, this should be done using a screening approach. This will make possible a determination whether to treat a patient or to refer them. A more comprehensive history and examination is indicated prior to undertaking any treatment.
• With bilateral involvement, designation of patient type should be based on the more advanced side.
• Imaging is seldom necessary to make the determination of patient type.
A screening panoramic film with good visualization of the TM joint condyles is desirable but not essential. More sophisticated imaging, when available, may enhance determination of patient type in some cases, however historical and clinical assessment is nearly always the most reliable basis for establishing a patient type and ultimately, a biologically-specific diagnosis
Each type of TMD represents a unique clinical challenge and must be understood as being clinically distinct from other types. The patient’s long-term best interest is served when their presenting symptoms and other clinical signs are seen as a reflection of the underlying problem, not necessarily as the problem itself. A thorough understanding of their problem, both anatomically and physiologically, will form the basis for addressing the actual problem that is producing the presenting symptoms. When considering which patients to treat and which ones should perhaps be referred, it is worthwhile to consider each patient type individually, as well as personal knowledge, skill, and experience.