DDS Orthodontics and Pediatric Dentistry 3

Question 1

In the mixed dentition, the ugly duckling stage is characterized by:

Accepted Answer

Spacing between the maxillary central incisors due to lateral incisor and canine pressure on the roots

Answer

Excessive crowding of the mandibular anterior teeth

Answer

Anterior crossbite of the permanent central incisors

Answer

Class III molar relationship during canine eruption

Question 2

Silver diamine fluoride (SDF) arrests dental caries primarily by:

Accepted Answer

Fluoride incorporating into hydroxyapatite while silver ions kill cariogenic bacteria

Answer

Mechanically sealing dentinal tubules with silver precipitate

Answer

Stimulating secondary dentin formation

Answer

Rehydrating demineralized enamel crystals

Question 3

The primary reason for placing stainless steel crowns (SSC) on primary molars with large multi-surface caries is:

Accepted Answer

Full coronal coverage provides superior longevity and fracture resistance compared to multi-surface amalgam

Answer

Aesthetic preference over composite restorations

Answer

SSCs stimulate eruption of the successor premolar

Answer

SSCs prevent adjacent teeth from drifting

Question 4

Non-nutritive sucking habits (thumb, finger, or pacifier) begin causing skeletal malocclusion risk primarily when:

Accepted Answer

The habit persists beyond the eruption of permanent incisors (approximately age 6–7)

Answer

The habit begins in the neonatal period

Answer

Any habit lasting more than 6 months in a primary dentition

Answer

The habit is performed during sleep only

Question 5

Enamel hypoplasia differs from fluorosis in that it:

Accepted Answer

Represents a quantitative defect in enamel thickness, while fluorosis is a qualitative (hypomineralization) defect

Answer

Affects only primary teeth, never permanent teeth

Answer

Always appears as white spot lesions, identical to fluorosis

Answer

Is caused exclusively by vitamin D deficiency

Question 6

The chronological age at which the human primary dentition is typically complete (all 20 primary teeth erupted) is approximately:

Accepted Answer

24–30 months

Answer

12–18 months

Answer

36–42 months

Answer

48–54 months