ABO Orthodontic Diagnosis and Treatment Planning 2

Question 1

A patient presents with a mandible positioned posteriorly and a convex profile. Which skeletal classification does this most likely represent?

Accepted Answer

Skeletal Class II

Answer

A retrognathic mandible with a convex profile is characteristic of a skeletal Class II relationship.

Question 2

On a lateral cephalogram, the ANB angle measures 7 degrees. What does this indicate?

Accepted Answer

Skeletal Class II tendency

Answer

An ANB angle greater than about 4 degrees suggests a skeletal Class II discrepancy.

Question 3

Which radiograph is most appropriate for evaluating impacted canine position in three dimensions?

Accepted Answer

Cone-beam CT (CBCT)

Answer

CBCT provides three-dimensional localization of impacted teeth and adjacent root resorption.

Question 4

The Bolton analysis is used primarily to assess what?

Accepted Answer

Tooth size discrepancy between arches

Answer

Bolton analysis compares the mesiodistal tooth-size ratio of maxillary to mandibular teeth to detect discrepancies.

Question 5

A negative value on space analysis in the mandibular arch indicates:

Accepted Answer

Arch length deficiency (crowding)

Answer

A negative discrepancy means available arch length is less than required, indicating crowding.

American Board of Orthodontics (ABO) Practice Test