Systemic factors influencing temporomandibular disorders: A wake-up call for dental clinicians

Temporomandibular disorders (TMDs) represent a diverse group of conditions with varied phenotypes. These may present as permutations and combinations of a plethora of signs and symptoms involving the temporomandibular joint, the masticatory and accessory muscles, and other associated and adjoint structures. Systemic factors are known to cause, aggravate, and perpetuate pain in general and TMD-related pain in particular.[1,2] Although various classifications have been proposed in an attempt to meaningfully group these disorders, none of these proposals seem to do justice to the role of systemic factors, conditions, and diseases in the presenting pain. Almost all (if not all) so called “TMDs” have comorbidities associated with them, some overt and others hidden. Prosthodontists encounter patients that may present and/or end with TMDs during the course of their patient management. Some of these cases may be rather perplexing; hence, a thorough knowledge on the systemic factors that may contribute robustly to these conditions is highly desired. Consequently, lack of understanding of these modifying factors may further complicate the management from both the patients and the clinician’s perspective.

One of the core principles of TMD management involves exploration into the routine cohort of patients that the dentist tries to manage. In order that this becomes possible, a good understanding of the prevalent and incident systemic conditions in the local geographic distribution is essential. For example, although same or similar laboratory tests can be employed for screening of our dental patients for systemic conditions, the results may vary vastly according to race, ethnicity, and the diversity of disorders endemic to the patient pool drawing area. In this context, the endemic diseases that prevail in Eastern and far Eastern countries may differ vastly from the patient population in the United States of America. In the same token, it is also essential to have succinct research as to what conditions may modify TMDs and TMD pain in the population being treated.

There are several systemic conditions and disorders that in their own or in combination manifest as musculoskeletal pain, with TMD pain reflecting the same. In the Indian context, the systemic disorders that make the TMD-related musculoskeletal pain challenging to diagnose and more refractive to management include hematological, endocrinological, infectious, autoimmune, and medication induced, among others. A patient presenting with anemia secondary to iron-deficiency or nutritional deficiency with concomitant musculoskeletal pain may not be uncommon in a cohort of Indian patients. Lack of recognition of this fact and inability to account for this systemic disease may cause unnecessary suffering and frustration for the patient and the treating clinician. Similarly, the rising levels of cases of thyroid and ovarian disorders in the Indian communities, most of which presenting with significant muscle pain, joint pain, and general fatigue may substantially contribute to TMD associated pain in these populations. Therefore, its highly desirable for us clinicians to explore these conditions before start of complex prosthetic management. Many patients may also need succinct interdisciplinary management, with referrals being facilitated by the savvy dental clinicians.

Fibromyalgia is a syndrome of global pain that can present to the dental clinician as “TMDs.” The associated comorbidities may include sleep disorders (such as insomnia), autoimmune conditions (such as systemic lupus erythematosus), infections (such as dengue and chicken guinea), and osteoarthritis. Further, concepts on the other associated conditions such as sleep-related bruxism, having gone through revolutionary changes in the past few decades, should prompt the clinician to explore the possibility of the role of systemic factors in a patient presenting with bruxism and TMDs.[3] The clinician confronted by cases such as this may be able to perform simple screening tests including laboratory investigations that may be instrumental in delineating the contributing systemic factors. This by all means is a game changer, not only for management, but also for improving the quality of life for these patients. Many a times, applications of relatively simple medical philosophies can change the life of these patients, their families, and us clinicians for the better. Studies have shown that the level of knowledge and understanding of TMDs by dentists, may be insufficient worldwide, the same being the case in India.[4] This may be compounded by the lack of reinforcement of medical knowledge in the context of TMDs and can be relatively easily rectified by succinct education.

A distinct class of systemic conditions that present with significant morbidity, especially in terms of musculoskeletal pain, including TMD pain is autoimmune disorders. The incidence and prevalence of this group of conditions is ever rising, both in global population, and the population in the Indian sub-continent. The exact etiopathology of these conditions are many a times ambiguous. However, most of them have been known to present with significant musculoskeletal pain, including TMD pain.[5,6] Unfortunately, there seems to be no sufficient coverage on the impact of such highly prevalent disorders on TMDs during many undergraduate and postgraduate curricula. This may further add to the complexity and ambiguity of the “TMD diagnosis.” Presumably, some of the related entities with possible profound effects on TMD pain include reactive arthritis, long coronavirus disease, nutritional deficiencies (Vitamin D, calcium, and others), and joint hypermobility. Reconciling such factors may be instrumental in appropriate treatment planning as well as optimal pain management. Conversely, lack of making appropriate adjustments to the management plan as per the preexisting systemic conditions may end in sub-optimal care.[6]

The dental literature pertaining to systemic conditions affecting TMDs is still lacking substance and volume. Dentists in general and prosthodontists in particular are vulnerable to the effects of systemic factors preexisting in their patients, affecting the treatment plans. Dental clinicians have a phenomenal opportunity and an ethical obligation in educating ourselves and applying the same succinct knowledge toward the betterment of the quality of life of our patients.