History and Development of the Activator Appliance
- Viggo Andersen first used the appliance on his daughter's teeth in 1908.
- Andersen saw positive results and began using the appliance in his private practice.
- Andersen and Karl Haupl coined the name 'Activator' for the appliance.
- The Activator was first mentioned in their textbook in the 1920s.
- The Norwegian System was the name given to their way of working with the Activator.
Indications and Malocclusions treated with the Activator
- Activator appliance is indicated for growing patients.
- Young adolescents with growth potential show the best results.
- Retrognathic mandible and well-aligned dentition are also indications.
- Malocclusions treated with the Activator include Class II Division I, Class II Division II, Class III, and Open Bites.
Mode of Action and Functional Adaptation
- The initial theory involved Isometric Muscular Contraction caused by Myotatic reflex activity.
- Another view focused on the Viscoelastic Properties of Muscle and stretching of soft tissues.
- Lateral pterygoid muscle was found to play an important role in mandibular condyle cartilage growth.
- Functional adaptation led to a new way of mandibular closing pattern.
- Different proponents had different views on the primary way of functional adaptation.
Components and Construction Bite of the Activator
- Activator consists of acrylic and wire components.
- Acrylic components include a horseshoe-shaped lingual plate and coverage of the anterior portion in the upper arch.
- Wire components include a labial bow placed 1mm away from the incisors and additional elements for stability.
- The construction bite can be Horizontal (H) or Vertical (V) Activator.
- H Activator involves bringing the mandible forward by 6-7mm and opening it by 3-4mm.
- V Activator involves bringing the mandible forward by 2-3mm and opening it by 7-8mm.
Types of Activators and Headgear and Activator Therapy
- Kinetor Activator was developed by Hugo Stockfish and had latex tubing for stimulation.
- Bow Activator of A.M Schwarz used an elastic bow for periodic adjustment.
- Herrens Activator included clasps for stability and maximal sagittal advancement.
- LSU or Shaye Activator leveled the occlusal plane by having lower incisors bite on acrylic.
- Elastic Open Activator of G. Klammt replaced acrylic with wires for flexibility.
- Propulsor, U Bow Activator, Wunderer Activator, Hamilton Expansion Activator, and Cybernator are other types of Activators.
- LM-Activator is suitable for treatment in early mixed dentition and other stages of dental development.
- Headgear and Activator Therapy can be done using the Stockli-Teuscher Approach or Hickam Approach.
Note: The remaining bullet points have been omitted due to exceeding the limit of 5 bullet list items per subtopic.
Activator Appliance is an Orthodontics appliance that was developed by Viggo Andresen in 1908. This was one of the first functional appliances that was developed to correct functional jaw in the early 1900s. Activator appliance became the universal appliance that was used widely throughout Europe in the earlier part of the 20th century.