The human temporomandibular joint (TMJ) consists of the condyle, the articular fossa, an articular eminence, an articular disc, and the joint capsule. The condyle has a cylindrical shape and is covered with cartilage on its front surface. Above it lies the articular disc, which is made of cartilage and is situated within the joint cavity, surrounded by a joint capsule. This disc divides the joint cavity into two sections. The articular fossa, which serves as the socket, is a depression in the temporal bone covered with cartilage. In front of it is the small articular eminence. The joint capsule, made of elastic fibers and connective tissue, enables the significant mobility of the TMJ.

What is the function of the TMJ?

Primarily, the movements of the TMJ are responsible for breaking down and chewing food. The mechanics of the TMJ are quite complex. The TMJ is a combination of two joints: an upper joint and a lower joint work together to create a type of "rotational glide." The right and left TMJs always function together.

In children, the permanent teeth are already formed in the jaw before the milk teeth have grown out. From the age of 6, the first molars begin to erupt. The space available for the molars is completely sufficient due to the growth of the jaw, as they do not replace milk teeth but grow behind the second milk molars.
However, the first permanent molars play a major role in further tooth replacement. A later lack of space for the permanent teeth is often due to problems during this phase of eruption. Typical problems are, for example, when milk molars are missing too early or are decayed and therefore lose their shape. As a result, the first permanent molars move into this gap and the subsequent permanent teeth have too little space to grow straight out.

Tooth change process
Between the ages of 6 and 8, the milk incisors fall out and are replaced by the permanent incisors. This is usually followed by the canines in the lower jaw, the small molars, the upper canines and finally the last large molars. As a rule, tooth replacement is completed at around 12 to 14 years of age and the dentition is complete. However, individual deviations in tooth growth are possible. Differences are particularly common with wisdom teeth, which can continue to erupt into adulthood. In some patients, the wisdom teeth may be missing altogether.