The temporomandibular joint (TMJ) is one of the most complex joints in the body because it joins a mobile bone, which is the mandible, with an immobile one at the base of the skull, and the movement of one side varies the position of the other. It is responsible for producing the opening and closing movements of the mouth, with the indispensable help, as in all joints, of the action of the muscles.
These muscles are basically two groups: those that raise the jaw or masticatory musculature, and those that open the mouth. The most important and true protagonists are the first ones.
The TMJ is a mobile joint and this makes it susceptible to suffer alterations in its functioning because it has to support an overload maintained over time. On the other hand, the masticatory musculature is very powerful, capable of developing a lot of force, since it is designed for mastication. All these loads or developed force is received by the mouth and the joints and, if it is not distributed within a balance that our joints can support, it can produce a pathology or develop failures, which alters the quality of life of the patient and influences feeding, swallowing and even speech. A very illustrative example could be to imagine a bridge in which all the forces it supports are not well distributed. If reinforcements are not placed where they are needed, cracks will start to appear, and it may even break.
What is the relationship between TMJ and bruxism?
Bruxism is defined as the involuntary and unconscious contraction of the masticatory musculature, but outside of chewing. The moments considered “out of chewing” are different from person to person. The night (during sleep) is the most common time, but there are people who also “grind” their teeth during the day, associated with moments of concentration or physical exertion, for example.
Bruxism is very common and is present from practically birth, it accompanies us during our adult life and can also occur in old age. It is the consequence of all these forces, applied on the teeth, gums and joints. It should be remembered that the masticatory musculature causes the mouth to close, which is why people commonly associate bruxism with clenching or grinding of the teeth.
The disorders that can cause bruxism, due to a bad distribution and adaptation to these forces, are Temporomandibular Disorders (TMD).
What causes Temporomandibular Disorders (TMD)?
There is no evidence of a single cause but it is something multifactorial derived, many times, from daily stress, daily worries and anxiety. In addition, there are other factors that may influence the fact that these joints are more prone to develop alterations, such as some types of bites or trauma to the face.
What are the symptoms of TMDs?
TMDs can produce symptoms derived from the alteration in the muscular system and can produce damage in the joint itself or both, which is usually the most frequent. The symptoms derived from the muscular overload are typical of the muscular contracture that derives from the repeated contraction, night after night, day after day, etc. It leads to sore spots on palpation of the different muscles, and pain. This pain is radiating, which means that it starts at one point and goes from there to other sites. It is usually described as the path it makes with a finger, being difficult to locate it in a single point.
It usually causes headaches (bruxism is the most frequent cause of headaches), earache, toothache (without dental pathology), gum pain, neck pain, etc. It is also frequent that, when eating, due to chewing and the use of that damaged musculature, there is pain or also when yawning, due to stretching of that musculature. It is like an athlete who has had a contracture in a muscle group and continues to play sports without resting for a while: he/she will develop discomfort.
It is also possible that there is also a sensation that the teeth do not fit together. This is due to the fact that the musculature, being contracted, changes the resting position of the jaw, causing its position within the joint to change as well. This produces alterations that would favor an inflammation inside the joint.
All this muscular symptomatology will always precede or coexist with the symptomatology that will cause the joint damage. Clicking or popping noises when opening and closing the mouth are typical of the onset of joint damage. They may occur occasionally, for example, when chewing or whenever we open and close our mouth. On the other hand, blockages, limitations of joint movement or the sensation of not being able to open the mouth completely are other symptoms that indicate the onset of deterioration. They are usually more frequent in the morning, after having been “clenching the teeth” at night. At the beginning, they are self-resolving, until they reach a point where, if not treated, a complete joint blockage may occur, which is one of the emergencies in TMDs.
And finally, pain is another of the main symptoms, which usually accompanies these clicks and locks. It is usually much more frequent when there is already a complete blockage and is due to inflammation of intra-articular structures. It is a pain very different from muscular pain and sometimes they coexist. Normally the patient can locate the pain with a fingertip in front of the ear, which is where the joint is. Just as muscular pains were radiating and had a course, this one is not. It is a pain that occurs with joint function: when opening and closing, when protruding or bringing the jaw forward or sideways. That is why for specialists in Oral and Maxillofacial Surgery the most complex thing is a correct diagnosis, in the differentiation between muscular and articular symptoms.
How to diagnose Temporomandibular Disorders?
For the diagnosis to be correct and for a good treatment plan to be established, it is important to go to a center where there are the necessary conditions to treat this problem from a global point of view. This means that various specialists cohabit: maxillofacial surgeon, physiotherapist and odontostomatologist. This is the most important element for a good diagnosis. Based on this, the treatment plan will be established after the examination.
The examination should lead to a suspicion: whether it is a purely muscular or myofascial condition, where the joints are adapted to this overload, or whether there is also joint overload (with the associated symptoms). On this basis, and when joint deterioration is suspected, a nuclear magnetic resonance will be requested, a test that provides information on the state and position of the articular elements, as well as their dynamics.
It can be said, then, that there is a clear relationship between bruxism and the development of temporomandibular disorders. It is necessary to go to a unit specialized in the global treatment of these conditions in order to achieve success in the treatment.