What is TMJ?

TMJ is an acronym standing for temporomandibular joint. If that sounds like a mouthful, let’s break it down to its basic components to get a good understanding of what the joint is.

Temporo refers to the temple, or the temporal bone, on the side of the skull. Mandibular references the mandible, or the jawbone. Taken together, the temporomandibular joint is the joint that connects the jawbone to the temple.

This joint is very important for actions such as chewing and talking. TMJ disorders are common and can cause pain, clicking or popping sounds when chewing, and locking of the jaw (1).  

 

What Are the Symptoms of a TMJ Disorder?

TMJ disorders mostly consist of similar symptoms, primarily pain near the joint, especially while chewing. Additionally, the temporomandibular joint itself may be swollen or tender (2,3). Yawning may also cause pain, and sometimes the movement of the jaw creates a clicking sound or a grating sensation.

TMJ disorders are usually localized to the joint on one side of the mouth; rarely will both sides be affected.

Other common symptoms can include reduced mobility of the jaw, which can create problems when chewing. In some cases, the jaw may actually lock, or its movements might deviate from its normal pattern (3). Occasionally, TMJ disorders are accompanied by headaches and teeth pain or hearing loss, tinnitus, and dizziness.

 

What Causes TMJ Disorders?

Because TMJ disorders comprise a group of related diseases, many factors may lead to the development of a specific TMJ disorder.

One common cause of chronic TMJ disorder is arthritis (4). Osteoarthritis (the most common type of arthritis) is a slow, gradual breakdown of the cartilage, causing bones to rub against each other at a joint. Rheumatoid arthritis, on the other hand, is an autoimmune disease in which the body’s immune cells mistakenly attack the joints (and sometimes other tissues). Both conditions can lead to the erosion of the cartilage around the temporomandibular joint, causing deformation of the joint and the hallmark symptoms of a TMJ disorder.

Another common factor leading to the development of a TMJ disorder is bruxism, or misusing the temporomandibular joint by clenching the jaw and grinding the teeth (5).

The jaw is primarily a hinge joint, meaning it only opens and closes, like the hinge of a door. While the joint also produces some side-to-side motions (like when chewing food), this is not its primary movement. Overusing and repeating the side-to-side, grinding action in this way can eventually lead to a TMJ disorder. Clenching can also put undue stress on the joint over time.

Finally, TMJ disorders can be caused by trauma to the joint and surrounding muscles (6). There may be many sources of trauma, such as a sudden impact, as in a car crash, or prolonged hyperextension during some dental treatments. These traumas can cause damage to the joint, ultimately resulting in a TMJ disorder.

Also, doctors and researchers speculate that other factors may lead to TMJ disorders. However, these are still poorly understood, and not enough evidence exists to confirm or deny these potential causative factors.

Stress has been implicated as a potential factor, mainly due to its contribution to bruxism (7). Researchers have also proposed a genetic predisposition to TMJ, but the evidence in this area is conflicted. The use of hormone replacement in postmenopausal women may contribute to the development of a TMJ disorder (4).

 

What can I do to make it better?

Most symptoms of TMJ disorders are not long-lived, and very few cases require medical attention.

The cause of the disorder may also be necessary for determining which is the best course of treatment. 

For example, trauma from overexertion (e.g., during a dental procedure) may only be treated by relaxing the jaw and refraining from opening the mouth very wide for some time (8).

Eating soft foods may also allow the joint to relax by requiring less force while chewing. These actions can often relieve symptoms quickly and resolve the disorder in several weeks or a few months.

If the TMJ disorder is caused by bruxism, behavioral intervention may be a course of treatment (7). This treatment option may involve a psychologist rather than a medical doctor or dentist. The goal is to reduce the patient’s tendency to clench their jaw and/or grind their teeth. By modifying behavior in this way, the temporomandibular joint will no longer be subject to undue stress and will recover on its own.

For a TMJ disorder caused by arthritis, the treatment will involve working to manage your arthritis.  

For very severe and chronic TMJ disorders, a surgical procedure may be necessary (9). Doctors try to avoid surgical treatment and will only resort to surgery if other treatment plans fail. Methods may involve joint replacement or cutting into the damaged area of the joint to repair it.

If you think you are having issues with your TMJ, contact your medical doctor and/or dentist.  

 

 

References

1. Prevalence of TMJD and its signs and symptoms. National Institute of Dental and Craniofacial Research. https://www.nidcr.nih.gov/research/data-statistics/facial-pain/prevalence. Accessed April 7, 2020.
2. Manfredini D, Guarda-Nardini L, Winocur E, et al. Research diagnostic criteria for temporomandibular disorders: a systematic review of axis I epidemiologic findings. Oral Surg Oral Med Oral Path Oral Radiol. 2011;112(4):453-462. DOI: 10.1016/j.tripleo.2011.04.021.
3. TMJ disorders. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/tmj/symptoms-causes/syc-20350941. Accessed April 7, 2020.
4. Cairns BE. Pathophysiology of TMD pain – basic mechanisms and their implications for pharmacotherapy. J Oral Rehabil. 2010;37(6):391-410. DOI: 10.1111/j.1365-2842.2010.02074.x.
5. De Meyer MD, De Boever JA. [The role of bruxism in the appearance of temporomandibular joint disorders]. Rev Belge Med Dent. 1997;52(4):124-138.
6. Liu F, Steinkeler A. Epidemiology, diagnosis, and treatment of temporomandibular joint disorders. Dent Clin North Am. 2013;57(3):465-479. DOI: 10.1016/j.cden.2013.04.006.
7. Orlando B, Manfredini D, Salvetti G, Bosco M. Evaluation of the effectiveness of biobehavioral therapy in the treatment of temporomandibular disorders: a literature review. Behav Med. 2007;33(3):101-118. DOI: 10.3200/BMED.33.3.101-118.
8. Aggarwal A, Keluskar V. Physiotherapy as an adjuvant therapy for treatment of TMJ disorders. Gen Dent. 2012;60(2):119-122.
9. Sebastiani AM, Baratto-Filho F, Bonotto D, et al. Influence of orthognathic surgery for symptoms of temporomandibular dysfunction. Oral Surg Oral Med Oral Path Oral Radiol. 2016;121(2):119-125. DOI: 10.1016/j.oooo.2015.08.012.