Temporomandibular joint (TMJ) disorders, or TMDs, are chronic conditions that affect millions of Americans. More often affecting women, compared to men, TMDs can severely affect a person’s overall health. TMDs can be found in up to 31% of adults and 11% of children (1).

Table of Contents

What is TMD?
Classifying TMD & Diagnosis
Symptoms
Causes
Treatment
Conclusion

What is TMD?

Temporomandibular joint disorders (TMDs) refer to conditions affecting the temporomandibular joint (TMJ), muscles of mastication, and associated structures. These disorders can manifest as pain and dysfunction in the jaw joint and surrounding muscles. TMD can lead to difficulty in jaw movements and chewing. TMD may result from a variety of factors including trauma, stress, dental malocclusion, or inflammatory diseases (2). Management typically involves a multidisciplinary approach including patient education, behavioral interventions, pharmacotherapy, and in some cases, surgical intervention (3).

Classifying TMD & Diagnosis

Temporomandibular disorders (TMDs) encompass a wide range of conditions causing pain and dysfunction in the temporomandibular regions, with multifactorial etiologies including physical and psychosocial factors. Physical causes are categorized into arthrogenous and myogenous origins, with internal derangement of the temporomandibular joint (TMJ) often preceding degenerative joint diseases like osteoarthritis (4). The diagnosis and classification of TMD are challenging because patients often present with multiple concurrent diagnoses, requiring a comprehensive assessment. Providers may utilize the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) to aid in diagnosis (5).

Symptoms

Symptoms of TMDs can vary amongst individuals. Symptoms can range from mild to severe discomfort. Symptoms are often associated with jaw movements and can involve a variety of locations and muscles. Symptoms are most commonly found within the muscles of mastication (6). These are some common symptoms that a person may experience. It is important to note not all cases of TMDs result in symptoms.

Jaw pain or dysfunction (6)
Earache (7)
Headache (8)
Facial pain (9)
Clicking, popping, or grating sounds in the jaw joint (10)
Limited jaw movement or locking of the jaw (6)
Muscle tenderness or spasm in the jaw area (11)
Dizziness (12)
Neck, eye, arm, or back pain (13)

Chronic TMD is defined by pain lasting more than three months.

Causes

The etiology of temporomandibular disorders (TMDs) is intricate and involves various contributing factors. These factors are grouped into predisposing, initiating, and perpetuating categories, with some factors fulfilling multiple roles (6). Successful management of TMD relies on identifying and addressing these contributing factors to control the disorder and promote healing. Etiological factors contributing to temporomandibular disorders include occlusal abnormalities, bruxism, trauma, joint laxity, and psychological stressors (14). These factors can initiate TMD symptoms and perpetuate the condition through behavioral, social, emotional, and cognitive influences while predisposing factors increase the risk of developing TMD by altering the masticatory system (15).

Occlusal Factors

Occlusion may play a role in a person’s susceptibility to TMD. A posterior cross-bite, overjet/overbite >5mm, centric relation/MIP >2mm, edge-to-edge bite, sagittal relation class III, anterior open bite, and 5 or more missing teeth have all shown possible correlations with TMD (16). Although occlusion remains a controversial etiological topic, it is often evaluated and considered when treating a person for TMD. Studies suggest varying degrees of contribution to TMD etiology. While some research suggests occlusal features may act as co-factors in TMD development, others emphasize the multifactorial nature of the condition (6).

Psychological Factors

Psychological factors, including stress and personality traits, play a significant role in temporomandibular disorders (TMD) (17), with patients exhibiting similar psychological profiles to those with other chronic musculoskeletal pain disorders. While there is substantial evidence linking psychological and psychosocial factors to TMD symptoms, their direct role in causing TMD remains less clear, with some suggesting that TMD symptoms may exacerbate or contribute to the development of psychological conditions like depression.

Hormonal Factors

Women are significantly more likely to experience signs and symptoms of temporomandibular disorders (TMD) and seek treatment for the condition more frequently than men (18). Women may be at more risk of developing TMD due to higher estrogen levels contributing to ligament laxity and increased susceptibility to painful stimuli. Although the direct link between female reproductive hormones and TMJ disease remains unclear, recent research suggests that estrogen and relaxin could disrupt cartilage homeostasis in the temporomandibular joint, potentially leading to degenerative changes (6).

Macrotrauma

Macrotrauma, particularly whiplash injuries to the head or neck, is recognized as a significant risk factor for temporomandibular disorders (TMD), Some studies suggest that the incidence of TMD pain after whiplash trauma can be as high as 34%, which is notably higher than the incidence in healthy controls (19). However, studies suggest that the direct incidence of TMD after whiplash injury is low, and individual trauma may not always be a triggering factor for the onset of TMD (20).

Parafunctions

Parafunctions, such as excessive gum chewing, teeth clenching, and bruxism, have been extensively studied as potential risk factors for temporomandibular disorders (TMD) (21). Studies have shown associations between these parafunctions and TMD symptoms, including joint pain, joint noise, and joint blockage, suggesting that repetitive overuse of the temporomandibular joint can lead to functional abnormalities and contribute to the development of TMD. The prevalence of bruxism is reported to be around 20% among adults, with higher rates observed in certain age groups, and longitudinal studies have demonstrated a significant correlation between bruxism and TMD over time (22).

Joint hyperlaxity and joint hypermobility

The relationship between hypermobility and temporomandibular disorders (TMD) has been explored, with some studies showing a positive association between generalized joint hypermobility and TMD. However, conflicting results have been reported, with some studies finding no significant association between TMD and systemic hyperlaxity. Further research is needed to clarify the relationship between hypermobility and TMD and the potential role of both local and generalized hypermobility in the development of TMJ dysfunction (23).

Treatment

Treatment for TMJ Disorders can fall into three categories, nonpharmacologic treatment, pharmacologic treatment, and occlusal splints. Dental providers will be able to evaluate and determine the appropriate treatment. In rare cases, surgery may be recommended.

Nonpharmacologic Management

Supportive patient education – patient education along with adjunctive measures which include jaw rest, soft diet, warm compress, and stretching exercises are the more effective methods of nonpharmacologic management (24)
Physical Therapy – Physical therapy, including active and passive techniques, may help alleviate symptoms of temporomandibular joint disorder (TMD), although evidence supporting specialized physical therapy options like ultrasound or electrotherapy is lacking (25).
Acupuncture – Acupuncture is a reasonable adjunctive treatment for short-term analgesia in patients with painful TMD symptoms (26).
Biofeedback – The benefits of counseling have been observed. Behavior modifications such as stress reduction and elimination of parafunctional habits (27).

Pharmacologic Management

Pharmacologic management is based on expert opinion. Several classes of medications are commonly used to manage symptoms of TMD.

NSAIDs – although there are multiple variations of NSAIDs available, only Naproxen has been shown to affect the reduction of symptoms (28)
Muscle relaxants (cyclobenzaprine) – these can be prescribed in conjunction with NSAIDs if the TMD has a muscular component (29)
Tricyclic antidepressants (amitriptyline, desipramine (Norpramin), doxepin, and nortriptyline (Pamelor)) – have shown statistically significant reduction in pain (30)
Benzodiazepines – can be prescribed but are limited to 2 – 4 weeks in the initial phase of treatment (31)
Anticonvulsants (diazepam (Valium), clonazepam (Klonopin]) gabapentin (Neurontin)) – may provide more benefit than shorter-acting agents. Valium in particular has been statically shown to reduce pain (31).
Opioids – these medications are not commonly prescribed or recommended. If they are prescribed, they are often prescribed for short-term pain management, due to their high risk of dependence (32).

Occlusal Splints

Occlusal splints are used to alleviate or prevent degenerative forces on the temporomandibular joint, articular disk, and dentition, particularly beneficial for severe bruxism and nocturnal clenching (33). Most occlusal splints will be worn at night while the individual sleeps, to avoid additional and unwanted functions, such as bruxism and clenching.

Surgical Intervention

Surgery is often a last resort for treating TMD. To qualify for surgery, patients would need to have severe and long-standing TMD. A diskectomy is a useful surgical procedure for said patients (34).

Conclusion

Temporomandibular joint (TMJ) disorders are prevalent chronic conditions characterized by pain and dysfunction in the jaw joint and surrounding muscles. TMD requires a multidisciplinary approach including patient education, behavioral interventions, pharmacotherapy, and sometimes surgical intervention for effective management. Treatment options encompass nonpharmacologic measures like patient education and physical therapy, pharmacotherapy with NSAIDs, muscle relaxants, antidepressants, and occlusal splints, and in severe cases, surgical intervention, as a last resort.

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