Biology of tooth movement

Extraction space is closed by moving the neighboring teeth through.




  • Teeth can be moved because of the periodontal ligaments on the roots (artificial implant has no periodontal ligament, thus is not movable).
  • Orthodontic force is transmitted to bone through periodontal ligaments.
  • When bone receives pressure, an inflammatory reaction will be triggered; followed by the activation of the bone-resorbing cells. Manifestation of inflammation is the sense of pain and discomfort.
  • The activated bone-resorbing cells then degrade the bone tissue. Inflammation will subside and pain gradually relieves.
  • The bone resistance diminishes from resorption, the teeth start to move.
  • When teeth move to the new position and orthodontic force declines, the new bone will start to form around the roots.
  • The similar cycle will repeat when next time a new orthodontic pressure is applied.