BIOLOGY OF TOOTH MOVEMENT

The movement of a tooth occurs due to the translocation of the tooth from one position in the jaw to another. Extrinsic forces applied to the crown of the tooth during physiological, therapeutic or pathological processes cause tooth movement. Orthodontic tooth movement differs markedly from physiological dental drift or tooth eruption. The former is uniquely characterized by the abrupt creation of compression and tension regions in the periodontal ligament (as a rule of thumb it can be said that bone subject to pressure as a result of compression of periodontal ligament resorbs while bone forms under tensile force as a result of stretching of the periodontal ligament).