Orthodontic traction: possible effects on maxillary canines and adjacent teeth Part 2: External cervical resorption due to canine traction

Professionals who resist and restrict the indication of orthodontic traction, especially canine traction, often justify their stance by citing the following reasons: 1) Lateral Root Resorption in lateral incisors and premolars. 2) External Cervical Resorption of canines due to canine traction. 3) Alveolodental ankylosis of the canine(s) involved in the process. 4) Calcific metamorphosis of the pulp and aseptic pulp necrosis. These possible outcomes do not stem primarily and specifically from orthodontic traction. They can be avoided if certain technical precautions are adopted, especially "the four cardinal points for the prevention of problems during orthodontic traction."2 To understand what these technical precautions are and how they work preventively against the possible consequences of orthodontic traction a biological foundation is required. Providing such biological foundation is the goal of this series of studies on orthodontic traction, focusing particularly on maxillary canines. The increasing use of imaging tests—such as computed tomography with its various slice planes, and the resulting reconstruction of 3D images, viewable from virtually every angle—allows today's professionals to plan orthodontic traction of maxillary canines with greater accuracy and refinement. This advance in obtaining image slices and 3D images allows surgeons to deal with canines, their follicle, cervical region and adjacent teeth with the aid of detailed planning, which ultimately reduces the risk of unintended outcomes. In other words, technological advances in imaging will make it possible for orthodontic traction to be accomplished more safely and accurately.