Abstract
Relapse is one of the commonest risk factors in orthodontics. Post-treatment changes following orthodontics could be due to periodontal or occlusal factors, but they can also be due to soft tissue changes and growth. Soft tissue changes and growth are beyond an orthodontist's control, and this explains the unpredictable nature of orthodontic relapse. Patients need to be informed of the unpredictable nature of relapse before they begin treatment, and the possible need for long-term retention to help reduce the amount of relapse.