The segmented arch technique uses the differential moment/force ratio in the anterior and posterior segments so that the extraction space in cases of critical anchorage can be closed with minimal or no anchorage loss. The objective of this article is to discuss the root correction phase, the force system involved, and the clinical problem of the tendency of space reopening during this phase. It also presents the use of a closed NiTi spring as a clinical alternative for this phase, concluding that this device can be used to avoid space reopening.
World J Orthod 2006;7:59–64.