Abstract: Third molars are the last development and eruption teeth. In the clinic, impaction of third molars are very common, especially the mandibular third molars. They always caused pericoronitis, dental caries, space infection, osteomyelitis and other diseases. They are usually required surgical extraction or orthodontic treatment. In the choice of the third molar extraction or retain, clinicians have different views. In orthodontic treatment, we often encounter the situation that extract the second molar or the first molar in mandibular, so retain the third molar to replace missing teeth becomes significant. The purpose of this article is to review some of the pertinent studies related
to the management of third molars in an orthodontic context. The clinician should base his or her decision to extract or not extract third molars on the most current scientific information and what is best for each individual patient.

Key words: third molar, impaction, orthodontic treatment