Abstract
Owing to a shortage in the orthodontic workforce in the United Kingdom, general dental practitioners carry out orthodontic treatment in selected cases. Orthodontic treatment may not always be successful due to various factors. Some of these limiting factors are related to the practitioner, others to the patients and the orthodontic appliances used. These three sets of factors were covered in the first part of this article. This second part deals with the biologic limitations of orthodontic treatment.