In most cases, since the right temporal bone is closed, the condyle of the lower jaw moves anteriorly, downward, and outward, whereas the left temporal bone is open. Hence, the condyle of the lower jaw moves posteriorly, upward, and inward. The relationship between the temporal fossa and disc and the condyle is misaligned, resulting in a problem with the temporomandibular joint. The fundamental treatment for this problem is that if the misaligned temporal bone and the condyle of the lower jaw are moved to a good position, the disc will naturally move to a good position. The treatment that makes this possible is the MCB splint.