ABO Orthodontic Biomechanics 4

Question 1

Which appliance design maximizes anchorage by grouping multiple teeth together?

Accepted Answer

Reinforced/reactive anchorage with multiple bonded teeth

Answer

Adding more teeth (and roots) to the anchorage unit distributes reactive force and resists unwanted movement.

Question 2

A temporary anchorage device (TAD) provides what type of anchorage?

Accepted Answer

Absolute (skeletal) anchorage with minimal reactive movement

Answer

TADs anchor into bone, delivering near-absolute anchorage without relying on other teeth as reaction units.

Question 3

Newton's third law is relevant to orthodontics because:

Accepted Answer

Every applied force produces an equal and opposite reactive force on the anchorage

Answer

The reactive force acts on the anchorage unit, which is why anchorage control is essential.

Question 4

Differential anchorage in extraction cases relies on the principle that:

Accepted Answer

Larger anchorage units move less than the units being retracted

Answer

By making the anchorage segment larger, it resists movement while lighter segments are retracted more readily.

Question 5

A transpalatal arch is commonly used to:

Accepted Answer

Reinforce posterior anchorage and control molar position

Answer

The transpalatal arch links the molars across the palate, adding anchorage and controlling molar rotation/width.

American Board of Orthodontics (ABO) Practice Test