Retention and relapse are critical phases in orthodontic treatment. After active treatment, teeth naturally tend to return to their original positions due to factors such as the elastic recoil of periodontal fibers, growth changes, and muscular pressures. Retention involves maintaining the corrected tooth positions using fixed or removable retainers until the surrounding tissues stabilize. Without proper retention, relapse may occur, potentially compromising the results achieved over months or even years of treatment. The stability of outcomes depends on several factors, including the severity of the original malocclusion, patient compliance, and age. In many cases-especially those involving rotations, spacing, or significant skeletal discrepancies-long-term or even lifelong retention may be necessary to preserve treatment results.