Bruxism and TMJ/TMD/TMJD, what's the connection?
First, a definition: The terms TMJ (Temporomandibular joint ) disorder, TMD (Temporomandibular disorders,) and TMJD (Temporomandibular joint and muscle disorders) are often used interchangeably. TMJD seems the most complete, so I'll use it for now.
If Bruxism is generally poorly understood (it is) then TMJD is a complete black hole. Please understand, it’s not for lack of trying. There are easily many hundreds and probably several thousand scholarly papers written on the topic. There are numerous therapies, multiple textbooks, and many professionals trying the best they can to provide relief for TMJD sufferers. However, the list of unanswered questions/unresolved issues is startling and includes:
- A universally recognized definition for TMJ
- Consistent diagnostic criteria
- Agreement on management protocol
- Understanding of causes
- Lack of randomized controlled trials
This is a partial list, but you get the point. I have read a great deal trying to understand what exactly is meant by TMJD. The best definition I found comes from the TMJ Association:
"Temporomandibular joint and muscle disorders (TMJDs) refer to a complex and poorly understood set of conditions that can cause pain in the area of the jaw joint and associated muscles and/or problems using the jaw. Both or just one of the TM joints may be affected. TMJDs can affect a person's ability to speak, eat, chew, swallow, make facial expressions, and even breathe."
According to the TMJ Association, symptoms may include:
- Intermittent pain is the most common symptom and is often described as a dull aching pain in the jaw joint and nearby areas, including the ear.
- Some people, however, report no pain, but still have problems using their jaws.
- Being unable to open the mouth comfortably.
- Clicking, popping or grating sounds in the jaw joint.
- Locking of the jaw when attempting to open the mouth.
- A bite that feels uncomfortable or “off”.
- Neck, shoulder and back pain.
- Swelling on the side of the face.
- Ringing in the ears.
- Ear pain.
- Hearing loss.
- Vision problems.
TMJD is thought to have any number of causes including trauma, tumors, poor oral habits, bad posture, malocclusion, bruxism, and arthritis. Therefore, all TMJD patients do not necessarily have bruxism. Additionally, all bruxism does not lead to TMJD. Indeed, some of the scientific literature doubts whether any causal relationship exists at all between bruxism and TMJD. However, the preponderance of evidence and opinion is tilted toward the belief that bruxism, at least in some cases, will lead to TMJD. Even if bruxism is not the primary cause of TMJD, we can be reasonably certain that bruxism, if present, cannot help the situation.