ABO Dentofacial Orthopedics Flashcards

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?

Answer: After 16–17 years of age

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

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

Answer: Inferiorly and posteriorly

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

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

Answer: Twin Block appliance

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

Protraction facemask therapy is indicated for which skeletal problem?

Answer: Skeletal Class III due to maxillary deficiency

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

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

Answer: Avoid dentoalveolar side effects like incisor proclination

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

During rapid palatal expansion (RPE), a midline diastema typically appears and then closes spontaneously because:

Answer: Suture opening pushes incisors apart and roots uprighting closes the diastema

As the suture opens, the upper central incisors tip apart, but the transeptal fibers pull the crowns back together as the suture ossifies.