ABO Orthodontic Diagnosis and Treatment Planning 3

Question 1

The Wits appraisal is measured by projecting points A and B onto which plane?

Accepted Answer

Functional occlusal plane

Answer

The Wits appraisal drops perpendiculars from points A and B onto the functional occlusal plane.

Question 2

Which of the following is a primary indication for extraction in orthodontic treatment planning?

Accepted Answer

Severe arch length deficiency with bimaxillary protrusion

Answer

Severe crowding combined with dental protrusion often requires extraction to relieve the discrepancy.

Question 3

A steep mandibular plane angle combined with a long lower facial height suggests which growth tendency?

Accepted Answer

Vertical (hyperdivergent)

Answer

High mandibular plane angle and increased lower face height indicate a hyperdivergent vertical growth pattern.

Question 4

The curve of Spee is best described as:

Accepted Answer

The anteroposterior occlusal curvature seen in lateral view

Answer

The curve of Spee is the anteroposterior curvature of the occlusal plane viewed from the side.

Question 5

In a growing Class II patient with a retrognathic mandible, which appliance approach is most appropriate?

Accepted Answer

Functional appliance to encourage mandibular advancement

Answer

Functional appliances harness growth to advance a deficient mandible in growing Class II patients.

American Board of Orthodontics (ABO) Practice Test