My thesis will be focussing on the orthodontic treatment of impacted teeth and I have concentrated chiefly on journal articles regarding this phenomenon to build a thorough understanding of it from all aspects, from cause to complications. In my thesis I will discuss the aetiology of impaction, possible sequelae, how impaction can be diagnosed, how impaction can be prevented, general treatment methods of impaction and the details of different treatment methods such as the open eruption technique. Different treatment methods will also be compared. In some cases, especially in the case of third molar impaction, extraction is necessary - which is linked to the field of oral surgery. Thus, my thesis primarily focusses on the impaction of maxillary canines and their orthodontic treatment, as their impaction is the most common after the impaction of third molars – whose treatment is typically by surgical extraction and does not involve orthodontic treatment. Unfortunately, as with most dental treatments, complications can also occur and I have investigated this, including periodontal changes that may take place after treatment. I have strived to make my thesis easy to follow yet give a thorough explanation of the subject.