ABO ABO Orthodontic Appliances and Mechanics 2

Question 1

What material property allows nickel-titanium wires to return to their original shape after deformation?

Accepted Answer

Superelasticity

Answer

Work hardening

Answer

Brittleness

Answer

Ductility

Question 2

A Class II elastics configuration runs from the upper canine to the lower first molar. What is the primary skeletal effect?

Accepted Answer

Mandibular advancement and/or maxillary retrusion

Answer

Mandibular retrusion

Answer

Maxillary advancement

Answer

Transverse expansion

Question 3

Which wire sequence is correct when beginning fixed appliance therapy?

Accepted Answer

NiTi → TMA → stainless steel

Answer

Stainless steel → NiTi → TMA

Answer

TMA → stainless steel → NiTi

Answer

Stainless steel → TMA → NiTi

Question 4

What is the purpose of placing a step bend mesial to an upper molar tube?

Accepted Answer

To prevent the molar from tipping mesially (anti-tip bend)

Answer

To intrude the molar

Answer

To tip the molar distally

Answer

To expand the molar buccally

Question 5

Self-ligating brackets differ from conventional brackets primarily because they:

Accepted Answer

Use a sliding mechanism instead of ligatures to engage the archwire

Answer

Have built-in torque values

Answer

Are made from ceramic material

Answer

Require larger archwires

Question 6

Which type of force system is produced by a T-loop spring during space closure?

Accepted Answer

Force and moment system

Answer

Pure moment (couple)

Answer

Pure force

Answer

No force or moment