The Herbst appliance--its biologic effects and clinical use.

The purpose of this article is to survey the Herbst bite-jumping method. An outline of appliance design and appliance construction is given. The effects of the treatment method on the dentofacial complex and on the masticatory system have been analyzed with the aid of dental casts, cephalometric roentgenograms, and electromyographic registrations from the masticatory muscles. The use and effectiveness of the Herbst appliance in the treatment of Class II malocclusions are exemplified by clinical cases, some of which were followed for 5 years after treatment. The Herbst appliance is most effective in the treatment of Class II malocclusions, provided it is used as indicated. Thus, the appliance must be limited to growing persons only. The treatment method should not be looked upon as a last resort to be used only when other treatment approaches have failed. Treatment prognosis is best in subjects with a brachyfacial growth pattern. Unfavorable growth, unstable occlusal conditions, and persisting oral habits after treatment are potential risk factors for occlusal relapses. As treatment with the Herbst appliance is performed during a relatively short period, the hard and soft tissues (teeth, bone, and musculature) would need some time for adaptation to the new mandibular position after the appliance is removed. Posttreatment retention as a routine with a removable functional appliance is therefore recommended.