The advancement 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 comply with the guidelines that have been in effect since 2004. In the area of prevention, current guidelines on fluoridation have been taken into account. New methods of cortical anchorage using implants or mini-screws are now addressed, along with established orthodontic and orthodontic-surgical treatment procedures. Finally, the chapter on the hygiene measures required in orthodontic practice has been revised to reflect the new hygiene standards.