ABO ABO Dentofacial Orthopedics 2 — Questions and Answers
Question 1: The Frankel appliance (function regulator) corrects Class II malocclusion primarily through:
- Applying direct forces to the teeth
- Eliminating abnormal lip and cheek muscle pressure, allowing the dental arches to develop (Correct answer)
- Advancing the mandible with an inclined plane
- Using extraoral forces
Correct answer: Eliminating abnormal lip and cheek muscle pressure, allowing the dental arches to develop
The Frankel appliance uses vestibular shields to remove lip and cheek pressure, providing an environment for unrestricted arch development.
Question 2: Which cephalometric measure is most commonly used to quantify the degree of mandibular advancement achieved by functional appliance therapy?
- SNA angle
- SNB angle (Correct answer)
- ANB angle
- Y-axis angle
Correct answer: SNB angle
The SNB angle measures the anteroposterior position of the mandible relative to the anterior cranial base, so an increase indicates mandibular advancement.
Question 3: Orthopedic treatment of a Class II skeletal patient is most effective when initiated:
- In the primary dentition
- During the pubertal growth spurt (peak growth velocity) (Correct answer)
- After all permanent teeth have erupted
- Only in adult patients
Correct answer: During the pubertal growth spurt (peak growth velocity)
Functional appliance therapy achieves the greatest skeletal effect when timed with the pubertal growth spurt because condylar growth potential is maximal.
Question 4: Slow maxillary expansion using a removable appliance achieves expansion primarily through:
- Suture opening at the midpalatal suture
- Dentoalveolar tipping of the posterior teeth (Correct answer)
- Direct bone apposition on the buccal cortex
- Intrusion of posterior teeth
Correct answer: Dentoalveolar tipping of the posterior teeth
Removable slow expanders produce mainly dentoalveolar buccal tipping of the upper posterior teeth rather than true sutural opening.
Question 5: The Andresen activator corrects Class II malocclusion by:
- Applying direct retraction force to the upper incisors
- Advancing and posturing the mandible forward during sleep (Correct answer)
- Using a spring mechanism to tip the lower molars forward
- Retracting the maxilla with labial bows
Correct answer: Advancing and posturing the mandible forward during sleep
The Andresen activator holds the mandible in a protruded position during sleep, directing condylar growth and restricting maxillary forward displacement.
Question 6: Cervical vertebral maturation (CVM) stage CS3 indicates:
- Pre-adolescent growth; no pubertal peak yet
- Approximately 1 year before the pubertal growth peak
- The peak of the pubertal growth spurt (Correct answer)
- Post-pubertal; growth is nearly complete
Correct answer: The peak of the pubertal growth spurt
CVM stage CS3, characterized by concavities on the lower borders of C2 and C3, corresponds to the onset and peak of the pubertal growth spurt.
ABO ABO Dentofacial Orthopedics 2
The Frankel appliance (function regulator) corrects Class II malocclusion primarily through: