Anatomy
The temporomandibular joint connects the lower jaw (the mandible) with the skull. It is formed by the upper jaw (the maxilla), which is rigidly connected to the skull, and the relatively movable lower jaw (the mandible) attached to it. The head of the joint (caput mandibulae) is part of the lower jaw and lies in the socket in the upper jaw (the mandibular fossa).
To the front, the acetabulum is limited by the tuberculum mandibulare (a bony elevation in the upper jaw, which prevents the head of the joint from slipping out of the socket (otherwise the temporomandibular joint would dislocate with every bite, which would be very impractical). A disc (a cushion of cartilage between the joint surfaces) divides the temporomandibular joint into two chambers that function almost independently of each other. Because of these two chambers, the joint performs a twist-slide movement when chewing and speaking. At the very beginning, when the mouth is opened, a pure rotary movement takes place in the temporomandibular joint. If the mouth is then opened even further than about 1 cm, the joint head together with the disc comes forward in a sliding movement.
Causes
Temporomandibular joint pain can have many different causes. In order to determine what exactly causes the pain, it is first necessary to observe when the pain occurs and whether it can be alleviated. Now an experienced dentist can search for the exact origin of the pain.
A common reason for temporomandibular joint pain is the so-called CMD (cranio-mandibular dysfunction). This means that there is a disorder somewhere in the temporomandibular joint itself. The reasons for this are manifold.
Another cause for jaw pain can be a jaw clamp as a result of a dislocated jaw. Dislocated jaw To prevent incorrect loading of the individual sections of the jaw, orthodontic treatment must be carried out correctly. If the patient does not have a suitable occlusion (when biting together, all teeth should fit together.
No tooth should come into contact with its antagonist in the opposing jaw too early and no tooth should get stuck in the air), this will lead to a permanent incorrect loading of one side of the jaw while chewing. The result is usually pain in the joint. But also tooth malpositions that have not been treated are pain triggers.
Then the jaw is loaded wrongly on one side and reacts with pain in the respective joint. If the wisdom teeth break through and then the occlusion changes, it must be checked if the removal of these teeth is not reasonable. In most cases the wisdom teeth (called 8s in the technical language) are not straight in the jaw and push the remaining teeth aside to make room for them.
In these cases, the mentioned occlusion changes and it can lead to incorrect loading and associated pain. In the case of teeth treated by a dentist, it is always necessary to make sure that the denture fits exactly. If the crown or bridge is too high, you only bite on one side and the chewing muscles tense up because they are not evenly stressed.
This tension then causes severe pain in the jaw joint. Fillings made on the occlusal surfaces of teeth must also be carefully checked afterwards for disturbing and early contacts. The dentist does this with a so-called occlusion foil.
The patient bites on the foil, which rubs off at the places where the teeth have contact. Disturbing areas are sanded down, because otherwise the chewing muscles are stressed on one side and tensions arise again. Harmful habits such as grinding or clenching teeth also lead to tense chewing muscles and thus to pain.
Most patients grind their teeth in their sleep and then wake up with a painful jaw. A bite splint can help here. Another cause is inflammation in the ear area or in the sinuses, which can easily spread to the jaw joint.
Viruses or bacteria infiltrate the joint capsule and accumulate in the synovial fluid, resulting in an inflamed joint. Arthrosis and gout not only occur in the hand, knee and foot joints, but can also occur in the temporomandibular joint. Here the discus can be destroyed or crystals can be deposited in the joint space.
This sometimes leads to severe pain in patients who generally suffer from gout or arthrosis. The disc, which cushions the head of the temporomandibular joint in its socket, can be displaced, i.e. it slides too far ventrally (anterior) or dorsally (posterior) from its original position. The disc ensures that the individual parts of the temporomandibular joint can work together smoothly.
If it is displaced now, the cooperation of the two chambers is disturbed.A distinction is made between complete discus displacement, in which the discus can no longer be repositioned and the mouth can no longer be opened normally, and partial discus displacement. In the latter case, most of the time a cracking sound is audible as soon as the mouth is opened and closed. Total prosthesis wearers can also visit a dentist because of pain in the temporomandibular joint.
Here it must be checked whether the prosthesis fits the patient and his occlusion or not. Often the normal position of the jaws in relation to each other is not taken into account when making total dentures. As a result, the patient is forced to bite in a certain position, which does not correspond to his natural bite position.
The disc in the temporomandibular joint is permanently compressed and defends itself by sending pain signals. In rare cases, cysts or abscesses are the cause of temporomandibular joint pain. A periodontal abscess on a tooth that is not treated and is naturally very painful, causes the patient to no longer want to chew on that tooth. The consequence is also here a one-sided load on the jaws.
