The “backbite” is commonly referred to as the “bite” or “pocket tooth”. Under normal circumstances, the upper front teeth are located in front of the lower front teeth when clenched. In the case of anticlinal malocclusion, the lower front teeth are located in front of the upper front teeth. In severe cases, the middle third of the face is sunken, the lower third of the face is protruding, and the side appearance is “crescent-shaped face”, which is a dental malformation that should be treated early. The most common type of malocclusion is crowded teeth. In addition to misalignment of teeth, crowded teeth often cause caries and periodontal disease, and affect the aesthetics. The main reason is that the actual length of the dental arch can not accommodate all the teeth, which is manifested by displacement, too low position or obstruction, twisting, tilting, etc. Bimaxillary protrusion is a malocclusion in which the teeth and alveolar bone of both the upper and lower jaws protrude forward. Open labial protrusion refers to the misalignment of the labiodental relationship caused by the underdevelopment of the upper lip or overdevelopment of the upper alveolar bone during development. Open bite Refers to the absence of occlusal contact between the upper and lower jaw teeth in the vertical direction when clenching the teeth, forming a shuttle-shaped opening through which a bright red tongue can be seen.