ABO ABO Dentofacial Orthopedics

Question 1

The rapid palatal expander (RPE) creates a midpalatal suture opening. At what age does this suture typically become interdigitated and difficult to expand non-surgically?

Accepted Answer

After 16–17 years of age

Answer

After approximately 16–17 years of age the midpalatal suture becomes heavily interdigitated, making non-surgical expansion increasingly difficult and unpredictable.

Question 2

A cervical-pull headgear applies force in which direction relative to the maxilla?

Accepted Answer

Inferiorly and posteriorly

Answer

Cervical-pull headgear pulls the maxilla inferiorly and posteriorly, which can increase lower facial height in growing patients.

Question 3

Which functional appliance is a one-piece, tooth-borne, mandibular advancement device that requires bilateral simultaneous engagement?

Accepted Answer

Twin Block appliance

Answer

The Twin Block appliance consists of upper and lower acrylic blocks with inclined planes that interlock to advance the mandible when the mouth closes.

Question 4

Protraction facemask therapy is indicated for which skeletal problem?

Accepted Answer

Skeletal Class III due to maxillary deficiency

Answer

Facemask (reverse-pull headgear) therapy applies forward traction to the maxilla to treat Class III malocclusion caused by maxillary undergrowth.

Question 5

Bone-anchored maxillary protraction uses mini-implants instead of tooth anchorage primarily to:

Accepted Answer

Avoid dentoalveolar side effects like incisor proclination

Answer

Skeletal anchorage for facemask therapy avoids the unwanted dental tipping of upper incisors and lower molars that occurs with conventional tooth-borne anchors.

American Board of Orthodontics (ABO) Practice Test

American Board of Orthodontics (ABO) Practice Test

ABO ABO Dentofacial Orthopedics