ABO (Reading) 3 — Questions and Answers
Question 1: When reading a panoramic radiograph, ectopic eruption of the maxillary canine is most often associated with which adjacent tooth resorption risk?
- Central incisor crowns
- Lateral incisor roots (Correct answer)
- First molar furcations
- Second premolar apices
Correct answer: Lateral incisor roots
Palatally displaced canines commonly cause resorption of the lateral incisor roots.
Question 2: In ABO case documentation, the term 'interproximal contacts' in the CR-Eval scores what aspect of the finished dentition?
- Absence of open spaces between adjacent teeth (Correct answer)
- Gingival color
- Root parallelism only
- Occlusal plane cant
Correct answer: Absence of open spaces between adjacent teeth
The interproximal contacts criterion checks that no open spaces remain between adjacent teeth.
Question 3: Which Angle classification describes a molar relationship where the mandibular first molar is mesial to the Class I position?
- Class I
- Class II division 1
- Class II division 2
- Class III (Correct answer)
Correct answer: Class III
A mesially positioned mandibular molar relative to Class I indicates a Class III molar relationship.
Question 4: Reading a cephalogram, an increased SN-mandibular plane angle typically indicates which facial growth pattern?
- Hypodivergent (horizontal) growth
- Hyperdivergent (vertical) growth (Correct answer)
- No relationship to growth
- Transverse deficiency only
Correct answer: Hyperdivergent (vertical) growth
A steep (increased) mandibular plane angle reflects a hyperdivergent, vertical growth pattern.
Question 5: In the ABO Discrepancy Index, which factor adds points for the anteroposterior discrepancy of the occlusion?
- Overjet
- Cephalometric ANB and other AP measures (Correct answer)
- Tooth color
- Gingival biotype
Correct answer: Cephalometric ANB and other AP measures
Cephalometric measures such as ANB contribute points to the AP component of the Discrepancy Index.
Question 6: When interpreting a Bolton analysis, an anterior ratio significantly above 77.2% indicates what?
- Excess mandibular anterior tooth material (Correct answer)
- Excess maxillary anterior tooth material
- Perfect balance
- Missing molars
Correct answer: Excess mandibular anterior tooth material
An elevated anterior Bolton ratio reflects relatively excess mandibular (lower) anterior tooth material.
Question 7: In radiographic reading, a well-defined radiolucency at the root apex of a non-vital tooth most likely represents which lesion?
- Periapical granuloma or cyst (Correct answer)
- Enamel hypoplasia
- Condensing osteitis
- Cemental spur
Correct answer: Periapical granuloma or cyst
A defined apical radiolucency on a non-vital tooth typically indicates a periapical granuloma or cyst.
ABO (Reading) 3
When reading a panoramic radiograph, ectopic eruption of the maxillary canine is most often associated with which adjacent tooth resorption risk?