ABSTRACT
Clear aligner treatment achieves patients' precise tooth movements through utilizing patients' digital dental models and tooth movement planning by orthodontists. Originated from the rudimentary form in 1940's, clear aligner has undergone many innovations and developments. A strict selection of extraction patients for clear aligner treatments is a prerequisite of good treatment outcomes. Orthodontists should first master the unique features of aligner biomechanics and mechanisms. For extraction patients treated with clear aligners, orthodontists should focus on anchorage control, torque control and vertical control, and strictly monitoring treatment progressions, as to achieve satisfactory treatment outcomes. With the development of dental materials and techniques, we believe that clear aligner treatment will be a mainstay of future orthodontic treatments.