Place of functional appliances in orthodontics.

Functional orthodontic appliances have recently captured the interest of a significant portion of the dental profession. In numerous articles and short courses, functional appliances have been portrayed as a new, low cost, easily managed and completely safe treatment modality. Claims have been made that they can make mandibles grow, can align the dentition without the need for extractions, and that because such treatment effects are achieved 'physiologically' they are thus inherently stable. Do functional appliances really work? The historical background to the development of functional appliances is described and the results of a number of clinical investigations are compared and discussed. Comment on the implications of functional appliance therapy is given and finally, a statement as to the rational use of functional appliances in practice is suggested.