The word orthodontics is a combination of two Greek words, originally translated as “orthodontics”. In recent times, due to the rapid development of this discipline, its scope has not only corrected the misalignment of teeth, but also expanded to the treatment of dental, jaw, cranial and facial relationships and abnormalities in the upper and lower dental arches and dental relations, so it is named “orthodontics”. Orthodontics is a sub-discipline of dentistry. Its subject matter is to study the malformation of human teeth, dentition, jaw and face and the abnormalities of masticatory organs; as well as the etiological mechanism, pathological diagnosis and analysis, orthodontic methods and preventive measures for the malformation of teeth, dentition, tooth alignment, jaw, craniofacial and other malformations that appear in the process of children’s growth and development. The aim of treatment is to achieve coordination of dental, cranial and facial shape through orthodontic treatment; as well as to improve masticatory function and jaw aesthetics. Orthodontics has a history of more than 160 years since the birth of the first movable aligner in 1848. It uses biomechanical mechanisms to slowly move the teeth within the alveolar bone. Its magic lies in aligning misaligned erupted teeth and adjusting abnormal occlusal relationships to normal, thus bringing multiple improvements to patients from functional to aesthetic, internal and external, including mental health.