The progress of science and the central importance of orthodontics in dentistry necessitated a new edition of the successful two-volume curriculum on orthodontics. In the fourth edition, the content has been updated and expanded in several chapters: the section on orthodontic treatment within the framework of statutory dental care in Germany has been adjusted to the guidelines in effect since 2004. In the area of prophylaxis, the current guidelines for fluoridation have been taken into account. New methods of cortical anchorage using implants or mini-screws are now addressed, as well as established orthodontic-surgical treatment procedures. Finally, the chapter on the hygiene measures required in orthodontic practice has been revised to comply with the new hygiene standards.