This is the main concern of every parent before their child’s orthodontic treatment. The movement of the teeth resulting from the force applied to the teeth by the aligners is a complex biomechanical movement. When the teeth are moved forward by appropriate biological forces (controlled by high-precision orthodontic appliances), the alveolar bone in front of the roots of the teeth resorbs, allowing the teeth to move forward, but at the same time, new normal alveolar bone is formed at the back of the roots of the teeth, which allows the teeth to grow securely in the new position and does not cause any pathologic changes due to the movement of the teeth. Therefore, there is no scientific basis for believing that teeth will fall out earlier after orthodontic treatment. It is to ensure the normal physiological movement of teeth, orthodontic treatment is relatively long, children need 1-2 years, adults need 2-3 years. If the orthodontic process blindly pursues a quick, short treatment, it will affect the formation of new bone around the teeth due to excessive force and rapid movement of the teeth, and ultimately lead to excessive loosening of the teeth and early loss of teeth.