Fixed appliances Flashcards
How is the straightwire appliance different from a standard edgewise?
Tip, torque, bucco-lingual positions are built into bracket prescriptions and don’t need to be placed into the archwire.
What is the mode of action of a tip edge appliance?
Teeth tip along the archwire instead of moving bodily, crowns tip into extraction spaces and then roots upright themselves.
What are the 3 stages of tip edge treatment?
1 – tooth alignment with overbite and overjet reduction 2- extraction spaces closed 3 – root uprighting, correct torque. Light class II traction can be used full time.
What are the advantages and disadvantages of ceramic brackets?
Good aesthetics, Disadvantages – increased friction between archwire and bracket reducing friction (can be rectified by adding stainless steel wire slot) Harder than enamel so can cause abrasion, fracture on debond.
What are the advantages and disadvantages of self-ligating brackets?
Adv – low friction, more robust ligation, reduced chairside time, full archwire engagement, OH can be easier. Dis – clips and gates can fracture, claims of effectiveness being scientifically challenged, expensive.
What are the two types of self-ligating brackets?
Passive and active (give more torque expression in working wires)
What are the advantages of lingual appliances?
Adv – aesthetics, Dis – Timely adjustments, can cause ulceration
What are T closing loops?
They assist with space closure – loops are added to the wire and are opened. The loops return to their initial position bringing the buccal teeth with them.
What are the desirable properties of an orthodontic wire?
High strength – withstand occlusal forces
Low stiffness can be engaged into a bracket
A range of deflection
Formability so that it can be bent into hooks
As little friction as possible
Biocompatible
Stability in oral environment
Low cost
