Space closure is one of the most challenging processes in Orthodontics and requires a solid comprehension of biomechanics in order to avoid undesirable side effects. The ability to close spaces, especially those resulting from tooth extraction, is an essential skill required during orthodontic treatment.Orthodontic tooth movement during space closure is achieved through two types of mechanics:friction mechanics & frictionless mechanics. This book aims to explore and compare the effectiveness of friction and frictionless mechanics.