ACTIVATOR

DEFINITION = Functional appliances are defined as ‘loose fitting or passive appliances which harness the natural forces of the orofacial musculature that are transmitted to the teeth and alveolar bone through the medium of appliance’.

ACTIVATOR 4m**

  1. Given by anderson and haul
  2. Also called as norwegian appliance or loose fitting appliance
  3. It doesn’t have any clasp to hold onto dentition normally 
  4. Only one wire component = labial bow

Mechanism of action 2m

  1. Pt has to forcibly hold the appliance in its place aka maxilla as its loose appliance with no clasps
  2. This causes the pt to bring his mandible forward and keep mouth closed so the activator doesn’t fall down. 
  3. When pt swallows = muscles get stretched, continous remodeling at TMJ and mandible stays in forward direction
  4. Mandible is staying forward due to a REFLEX – myotatic reflex = due to continuous stretch of muscles, kinetic energy is generated and transferred to maxillary and mandibular dentition and skeletal base. Leading to: 
    1. Distal force on maxilla
    2. Mesial force in mandible 
    3. Hence, condylar adaptation occurs
  5.  ‘viscoelastic property’ = passive tension caused by stretching of muscles, soft tissue, tendinous tissue, etc. are responsible for the action


Indications 2m

  1. Class II division 1 malocclusion
  2. Class II division 2 malocclusion
  3. Class III malocclusion
  4. Class I open bite malocclusion
  5. Class I deep bite malocclusion
  6. As a preliminary treatment before major fixed appliance therapy to improve skeletal jaw relations
  7. For post­ treatment retention
  8. Children with lack of vertical development in lower facial height.

Contraindications

  1. Crowding 
  2. Adult pt 
  3. Too much proclination of lower anteriors 
  4. Increased lower anterior facial height

Advantage

  • pt can remove it
  • oral hygiene is maintained
  • no food restrictions
  • chair side time is less

Disadvantage = pt compliance

TYPES of activator 

  1. H activator 
    1. Horizontally growing pt
  2. V activator 
    1. Vertically growing pt 

FABRICATION STEPS

  1. Take impression
  2. Bite registration = gives us an idea how much mandible needs to be displaced. U shaped wax is placed on the oral cavity and asked to bring it forward and the bite is also opened posteriorly. 
  3. Articulation
  4. Wire elements  
  5. Acrylization of appliance
  6. Trimming = to bring about certain movements of the dentition

MODIFICATIONS 

BOW ACTIVATOR 

  • WUNDERER MODIFICATION = Given in class 3 
  • CYBERNATOR = similar to bionator = activator with reduced palatal acrylic 
  • PROPULSOR
  • Cutout or palate free activator
  • Karwetzky modification 
  • Herren modification 
  • Elastic open activator
  • Kinetor by Stockfish 

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