Indirect bone resorption in orthodontic movement: when does periodontal reorganization begin and how does it occur?

Tooth movement induced by orthodontic appliances is one of the most frequent therapeutic procedures in clinical dental practice. The search for esthetics and functionality, both oral and dental, demands orthodontic treatments, which are often associated with root resorptions that may, in extreme cases, lead to tooth loss, periodontal damage, or both. The knowledge of induced tooth movement biology, based on tissue, cell and molecular phenomena that take place on each day during movement progression, enable us to act safely and consciously when using drugs, procedures and interventions to optimize orthodontic treatment and patient comfort, to reduce or avoid root resorptions and to treat systemically compromised patients.