ABO ABO Growth and Development

Question 1

The primary site of mandibular growth that contributes most to mandibular lengthening in adolescents is:

Accepted Answer

Condylar cartilage (endochondral growth at the condyle)

Answer

Mental symphysis

Answer

Coronoid process

Answer

Gonial angle region

Question 2

Normal primary (deciduous) dentition eruption begins with which tooth?

Accepted Answer

Lower central incisor

Answer

Upper central incisor

Answer

Upper first molar

Answer

Lower first molar

Question 3

The 'ugly duckling stage' of dental development is characterized by:

Accepted Answer

Spacing and flaring of upper central incisors due to erupting lateral incisor and canine crowns

Answer

Crowding of all four lower incisors

Answer

Anterior open bite from finger sucking

Answer

Retained primary canines in the mixed dentition

Question 4

Which of the following is a normal finding in the early mixed dentition that does NOT require orthodontic intervention?

Accepted Answer

Mild crowding due to tooth-size/arch-size discrepancy that may self-correct

Answer

Posterior crossbite with mandibular shift

Answer

Anterior crossbite of a permanent incisor

Answer

Severe Class III skeletal pattern

Question 5

The 'leeway space' in the mixed dentition refers to the size difference between:

Accepted Answer

The combined primary canine and molars versus the combined permanent canine and premolars

Answer

Upper and lower first molars

Answer

Upper and lower incisors

Answer

Primary central and lateral incisors

Question 6

Eruption of the permanent first molars into a flush terminal plane primary dentition most commonly results in which permanent molar relationship?

Accepted Answer

End-to-end permanent molar relationship initially, typically resolving to Class I

Answer

Class III molar relationship

Answer

Class I molar relationship after mesial step develops

Answer

Class II molar relationship