Normal people will not bite their teeth together when their mouths are relaxed. 1. When a normal person’s mouth is relaxed, he or she is in the resting jaw position, also known as the mandibular posture position, at which time the muscles around the jaw are in the most relaxed state, and the force exerted by the muscles is also minimized. In the standard jaw posture, the teeth are not in contact with each other, and there is a wedge shape from the back to the front, with a gap of 3~4mm between the front and the back, which is called the resting jaw gap. 2. If the teeth are clenched together, then the mouth is not in a relaxed state. It is necessary to propose that many people patients will exist in the habit of unconsciously clenching teeth, it is recommended to try to correct or wear jaw pads to protect the joints from damage. In a good oral cavity, teeth, jaws, muscles and temporomandibular joints all play important roles, and an imbalance in one of them may lead to abnormal oral function.