Relapse is an unpredictable risk factor for every patient. Before treatment begins, patients need to be informed of the long-term risk of relapse and the ways that this may be reduced. Some causes of relapse are within the control of the orthodontist, but others such as soft tissue changes and latent growth are not, and may explain long-term changes in tooth position. Therefore, retention after orthodontic treatment has been recommended by several authors and orthodontists. The objective of the retention phase is to maintain teeth in their corrected position after orthodontic treatment. This article aimed to review the causes of relapse and the ways that reduce it using retainers and other new adjective techniques.