Activator
A removable myofunctional appliance that harnesses jaw-muscle forces to influence mandibular growth and correct Class II malocclusions in growing patients.
Full Definition
The activator, introduced by Viggo Andresen in the early twentieth century, is a bulky removable appliance that positions the mandible forward and downward, transmitting muscle and soft-tissue forces to the dental arches and condyles. It belongs to the broader category of functional appliances and is used during the pubertal growth spurt to redirect mandibular development. Editors should note that multiple design variants exist—Andresen activator, Harvold activator, Bass activator—and that specific appliance names should be capitalised as proper nouns when referring to their eponymous designs. The activator should not be confused with the Herbst appliance, which is fixed rather than removable.
Usage
Usage note: Capitalise only when referring to the specific Andresen Activator by name; use lowercase 'activator' as a generic appliance category.
In Context
- "The patient wore the activator for 14 hours per day during the peak growth period to maximise its orthopaedic effect." — Case report methods section
- "Unlike the Herbst appliance, the activator relies on patient compliance, which must be discussed in the limitations section." — Systematic review