[Extraction in orthodontics: when and why?].

Abstract

During the last century orthodontic treatment philosophies changed continuously. The necessity to extract teeth in order to correct a lack of space has many times been the subject of discussion. In fact there exists several techniques which make it possible to avoid extractions in many cases. A number of criteria which influence the decision to extract or not, as well as some techniques to regain space in upper and lower arch are discussed.