Normal people shut up when the jaw is generally in the mandibular posture position or cusp staggered position, mandibular posture position when there is no occlusal contact between the upper and lower teeth, cusp staggered position when the upper and lower teeth are in the widest contact relationship, as follows. 1. Mandibular posture position: when a person is sitting upright or sitting, not chewing, not swallowing, not talking, usually there is no occlusal contact between the upper and lower jaw teeth, forming a wedge-shaped gap between the front and the back of the large and small, the size of the wedge-shaped gap may change with the changes in body position. 2. Cusp staggered position: when some people shut up, the upper and lower jaw teeth reach the widest and closest stable contact, that is, the so-called teeth alignment, at this time the position of the lower jaw is called cusp staggered position.