Orthodontics - Fixed Appliances Flashcards
Describe a fixed appliance.
An appliance which is fixed to the teeth and cannot be removed by the patient
- Precision tooth movers as they can move the teeth in 3D planes using varying forces
List the features of a fixed appliance. (7)
- 3D control (crown and root)
- Complex tooth movements
- Control of root
- Less dependent on compliance
- Requires excellent oral hygiene
- Risk of iatrogenic damage (decal, root resorption, relapse)
- Poor intrinsic anchorage as no baseplate
When are fixed appliances used? (7)
- Correction of mild to moderate skeletal discrepancies
- Camouflage: accept the underlying skeletal base and treat the malocclusion to create a class 1 relationship.
- Alignment of teeth
- Correction of rotations
- Centreline correction (correct midline deviations)
- Overbite and overjet reduction
- Closure of spaces/ creating spaces
- Vertical movements of teeth e.g. intrude and extrude
What are the treatment goals of fixed appliances? (7)
Andrews 6 keys:
- Tight approximal contacts with no rotations.
- Class I incisors.
- Class I molars.
- Flat occlusal plane or slight curve of Spee
- Long axis of the teeth have a slight mesial inclination except the lower incisors.
- The crowns of the canines back to the molars have a lingual inclination.
7th key : tooth proportion, sizes and formation must be within normal average.
Describe the advantages of a bracket fixed appliance system.
prescriptions incorporated;
Each bracket will have the inclination, angulation and torque already pre-incorporated into the bracket system
What bracket prescription is used in the GDH?
MBT
How are ortho brackets bonded to teeth?
Bond via composite and an acid etch technique – uses micromechanical retention
Describe how brackets are placed. (5)
- Polish the tooth using pumice and water
- Isolate the tooth
- Tooth prepared with Self etch primers with tooth agitation
- Brackets can be precoated or can manually coat with composite
- Attached to the tooth with the locating dot distal gingivally
In which location should the brackets locating dot be on the tooth?
locating dot distal gingivally
What are the advantages of a precoated bracket?
What is the disadvantage?
- Quicker and efficient
- Less flash to remove
X – more expensive
Where are orthodontic bands placed and why?
on posterior teeth as they are not aesthetic
What material is used to bond ortho brackets?
GIC
Why are ortho bands used? (2)
- when teeth don’t have sufficient enamel for braackets to bond to (i.e. heavily restored)
- provides an end stopping point of the appliance (orthognathic patients)
What is the alternative to a molar band?
List the advantages. (4)
molar tubes;
Advantages of molar tubes:
- More discrete
- Less irritating to the soft tissues
- Less cover-some
- Petite on the tooth
(Can be used on upper and lower 6’s and 7’s)
What material are working archwires made from?
stainless steel
