There are many reasons for facial asymmetry, and a crooked face is not an inevitable result of TMJ disorder, but there are individual patients who may have a crooked face due to TMJ disorder. In young patients, especially those with TMJ disorders that develop in adolescence, if the joint structure is disordered and they do not receive correct and timely treatment, because the bone is not fully developed in this period, the disordered joint structure will resorb the joint bone and the condyle will become shorter during the long-term collision and wear in the process of movement, resulting in the shortening of the lesion side compared with the normal side, which will lead to the performance of crooked face. In addition, some patients use one side of the teeth to chew for a long time due to habit, missing teeth, bad teeth, etc. This will not only increase the burden on the joint in the long run, but also the muscles on the chewing side will be relatively enlarged, resulting in facial asymmetry. Lateral chewing is also one of the causes of TMJ disorders, so it is important to avoid chewing on one side, and it is recommended to chew meals bilaterally at the same time or alternately.