Fixed Orthodontic Appliances Flashcards
What are fixed appliances?
An appliance which is fixed to the teeth and cannot be removed by the patient.
When do we use fixed appliances?
Correct of mild to moderate skeletal discrepancies
Alignment of teeth
Correction of rotations
Centreline correction
Overbite and overjet reduction
Closure of spaces/creating spaces
Vertical movements of teeth
What are the components of fixed appliances?
Archwire
Brackets
Elastomeric modules
Molar tubing
Molar band
Anchorage components
Force generating components
What materials can brackets be made from?
Metal- SS (most common), CoCr, Ti, Au
Polymers
Ceramics
What is used to bond ortho bands to molar teeth?
Glass ionomer
What must be done first before placing orthodontic bands on molar teeth?
Create space- place separators
What material is used to bond brackets to teeth?
Composite- micro mechanical retention.
- can use self etch or etch and then bond.
Why is Nickel Titanium used as the first type of wire in fixed ortho appliances?
Flexible
Light continuous forces
Shape memory- returns to original shape, cannot bend.
Higher friction than stainless steel
Why is stainless steel used as the second type of wire in fixed ortho appliances?
Used to slide teeth easier because it has low friction.
What is the function of elastomeric ligatures?
Keeps the wire within the bracket.
What is the function of bumper tubing?
Used where there are large extraction spaces- this will create space to alleviate crowding.
Used to prevent soft tissue trauma in the event that the wire pops out of the molar bands.
What is the purpose of stainless steel arch wire with spring?
Makes space for teeth- i.e. instanding laterals.
What are the force generating components in fixed appliances?
Sliding mechanics
- elastic power chain
- NiTi coils- to push teeth apart or close space
- Intra-oral elastics
- Active ligature
What is an elastomeric power chain?
Runs from the tube hook to the brass wire hook.
Used to close spaces.
What are Nickel Titanium coil springs?
Used to push teeth apart.
What is the purpose of intraoral elastics?
Distal or mesial movement of teeth.
i.e. in class II cases- move the lower teeth distally and upper teeth medially.
What is anchorage?
Resistance to unwanted tooth movement.
Must plan this carefully to avoid unnecessary complications.
What types of anchorage can you get?
Simple- using teeth within the same arch, as well as anchorage components- elastomeric power chain used to pull one tooth that is linked to another tooth with a higher root surface ratio.
Compound- linking groups of teeth together as a unit, increases the root surface area.
Reciprocal- one tooth is linked to another similar tooth- same root surface area, so both teeth will move together since both forces are balanced.
What is absolute anchorage?
Using temporary anchorage devices
Give an example of a type of temporary anchorage device?
Non osseointegrating mini screw
- Inter-radicular TAD
- Palatal TAD
What devices can be used to maintain cortical anchorage?
Transpalatal arch
Nance palatal arch
What can be used for inter- maxillary anchorage?
Intermaxillary elastics
Class III elastics- run from lower canine to the upper molar
Class II elastics- run from upper canine to lower molar.
What is retention?
Maintaining the final tooth position with a passive orthodontic appliance.
Designed to prevent relapse.
What malocclusion features have a high relapse potential?
Instanding upper laterals
Diastemas
AOB
Rotations
Palatally ectopic canines
Proclination of lower incisors
These patients would benefit from a fixed orthodontic retainer.
What types of retainer are available for patients?
Hawley conventional retainer
Vacuum formed retainer
Fixed orthodontic retainer
What do you want to check with a lingual bonded retainer at each check up?
Check composite is still firmly adhered to tooth surface.
Ensure no calculus despots present around composite or wire.
No sharp bits of wire.
Wire hasn’t fractured.
