Activator's Flashcards
This uni has a weird way of explaining this so I will do my best to tell you the differences by way of components, forces and the class occlusions it acts upon Also note: the question is asking for corrective appliances based on the inclined plane principle. So let's talk about adjustments we can make on this appliance in order to correct those discrepancies
What is the relationship b\w and Activator and Monoblock?
Principle is the same - to correct myofunctional abnormalities and correct arch positioning.
To relate to the syllabus:
Activator is used for: Class 2 in general
Monoblock is used for: Class 2 D1 or Class 3
Class 2 relates to distalisation of the mandible - thus we can correct with protrusion of the mandible and limited expansion of the maxilla
Class 3 relates to the mesialisation of the mandible - thus we can correct with retrusion of the mandible (though difficult) by adjusting condyle and musculature r/ships and including maxillary palatal expansion
Are functional appliances fixed or removable?
Removable, with the exception of the Twinblock
Which arch is are primary focus in correcting the saggital discrepencies?
Mandible
Protrusion or Retrusion
Indications for an activator?
Class 2 D1
Class 3
Class 1 Open bite or Deep bite
Ptx requires a forward movement of the mandible
Ptx requires minimal vertical height closure
Ptx requires vertical height expansion
Ptx is in a growing phase - Late Primary - Early MD (known as primary transition)
Contraindications?
Crowding Excessive vertical height Severe proclination of lower incisors Allergies Nasal obstructions
Functions of an Activator?
Musco-skeletal adaptation
Myofunctional correction
Passive tension (can influence positioning of developing dentition)
In simple, activates the masticatory muscles
Will it correct orthodontic discrepencies?
Alone, it can correct arch width and growth. Positioning of the mandible and maxilla
However, for individual tooth discrepencies, Fixed Bracket Appliances will be required when the full dentition erupts.
Components to an activator?
Acrylic Base x 2
Wire Elements:
- Labial Bow (max for C2 and in man for C3)
- V-loops for retention x 2 b/w canine and p1 or canine and m1 (if pre’s are unerupted)
- H-loops - sit in between the labial bow and can include active springs or expansion screws if required
Steps of fabrication? (4)
1) Construction of the bite
2) Fabrication of the Activator
3) Trimming
4) Management
Importance of step 1?
Position mandible forward in correct occlusal bite plane for C2 or retrude mandible (as much as possible) for edge-edge in anterior segment
This position is the template of the impression and will be held in place with wax. The goal is to get as close to a C1 relationship
Importance of step 2?
Putting components together for the desired result:
1) Take 2 impressions
2) Acrylic base w/ wax w/ registration of desired bite (make it 2-3mm thicker than desired)
3) Place models on articulator
4) Prepare the wire elements:
- Retention clasps
- Active loops/bow (V, H, LB w/spring or screw)
- Pads for passive action
5) Cure the final product and polish to avoid soft tissue trauma - ensure the acrylic plate and retentive clasps have correct tooth contact
Importance of step 3?
Trimming is very important. What we trim and how much influences the result the activator will produce.
The relationship between the labial bow and acrylic base plate will influence tipping
If we need arch expansion then we may also include a jack screw (as in Schwarz Activator)
Trimming focus points? (4)
Intrusion
Extrusion
Proclination
Retrusion
Importance of step 4?
Adjustments to achieve the best results as the ptx is developing
What is the upper anterior inclined bite plane?
Allows for protrusion of mandible. Attaches to the maxilla
Reduces the amount of effort required to move the mandible forward
Guard at maxillary incisive papilla to avoid extension of mandibular incisors beyond that point
