European Journal of Molecular & Clinical Medicine

Abstract

The term functional appliance refers to a large and diverse family of orthodontic appliances designed mainly to correct Class II malocclusion. They were developed primarily in Europe but have been adoptedby orthodontists in many countries. They all work by posturing the lower jaw forward, the stretched musculature and soft tissues creating a force, which is transmitted to the dentition. In addition, the soft tissue envelopesurrounding the teeth is changed. This results in tooth movement, establishment of a new occlusal relationship and reduction of the overjet. The efficiency of these appliances in the correction of sagittal discrepanciesin growing patients has intrigued orthodontists for many years, particularlythe question of whether they significantly affect skeletal growth. There has been a lot of mystery and misinformation associated with their use, often supported by quasi-scientific theories of growth.¹ Many of the claims made in association with these appliances are in the form of case reports, or retrospective studies, using unreliable and over-complicated cephalometric analyses, with all the inherent bias associated with these types of study.¹ More recently, the results of several large prospective clinical trials have provided the best evidence of what these appliances can do and equally importantly, whatthey do not do.The development and use of functionalappliances was pioneered in Europe early in the twentieth century, at the same time thatfixed appliances were being developed inthe USA. A simple monobloc appliance wasdescribed by Pierre Robin in 1902 for use inmandibular retrognathia and functional jawexpansion, it was the precursor of the applianceused for the treatment of Class II malocclusionsdescribed by Viggo Andresen while working at the dental school in Oslo. The storygoes that following fixed appliance therapy on his daughter he fitted her with a modifiedupper Hawley type retainer with a lowerlingual flange that guided the mandible forwardinto an ideal inter-arch relationship. Theappliance was fitted as a retainer during herthree-month summer holidays to be worn atnight, and it corrected her Class II relationship.Andresen refined the technique and appliance,with the assistance of Karl Häupl, and coinedthe phrase ‘functional jaw orthopedics’ toencapsulate their philosophy of how the appliancesworked. A detailed history on functionalappliances and the personalities involved hasbeen published by Levrini and Favero.^1-5