For effective tooth movement with a removable appliance, consistent force application is essential. Wearing the appliance for at least 4-6 hours/day ensures sufficient force duration to stimulate bone remodeling and periodontal ligament adaptation without causing excessive patient discomfort. Wearing the appliance for fewer hours results in an interrupted force application, reducing treatment efficiency. Continuous forces shorter than this period fail to generate adequate biological response, while excessive wear may affect compliance. Therefore, a minimum of 4-6 hours/day balances clinical effectiveness and patient adherence for successful tooth movement.

Reference: Proffit, Contemporary Orthodontics, 6th Edition.