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

The ugly duckling stage occurs when erupting permanent lateral incisors and canines press on the roots of the centrals, causing them to flare and create a midline diastema that self-corrects on 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

SDF arrests caries through dual action: fluoride ion remineralizes and hardens enamel/dentin while silver ions (Ag+) provide broad-spectrum antimicrobial activity against cariogenic bacteria.

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

Stainless steel crowns provide complete cuspal coverage that resists fracture from masticatory forces, making them significantly more durable than multi-surface direct restorations for primary molars with extensive decay.

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

Non-nutritive sucking during the primary dentition rarely causes permanent skeletal changes; skeletal open bite and Class II risk significantly increase if the habit persists into the permanent dentition.

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

Hypoplasia is a quantitative defect (reduced enamel formation/thickness) from any systemic or local insult during matrix formation, while fluorosis is a qualitative hypomineralization from excess fluoride during maturation.

DDS - Doctor of Dental Surgery Practice Test

DDS - Doctor of Dental Surgery Practice Test

DDS Orthodontics and Pediatric Dentistry 3