The uneven teeth will affect the face shape as follows: a. When the dental arch is narrowed and the teeth are severely crowded, the front teeth move in a lipward direction, causing the upper jaw to protrude forward, resulting in the phenomenon of open lips and exposed teeth, and the face shape is convex, which affects the appearance. Second, when the teeth are not aligned with the lower jaw forward and other habits, the formation of anti-collapse and anti-coverage, the facial shape is concave, the tongue movement is restricted, resulting in unclear pronunciation. Third, misaligned teeth can produce early contact or joint interference, resulting in uneven tooth wear, small vertical distance, and too short lower 1/3 of the face. Fourth, misaligned teeth can form lateral chewing habits, causing one side of the jaw face to be plump and the other side to be thin, resulting in serious facial asymmetry, and even inducing temporomandibular dysfunction syndrome.