DDS Orthodontics and Pediatric Dentistry 1 — Questions and Answers
Question 1: The leeway space (E-space) refers to the size difference between which groups of teeth?
- Primary incisors and permanent incisors
- Combined width of primary canine and molars minus combined width of permanent canine and premolars (Correct answer)
- Space between the permanent first molar and permanent canine
- Arch length increase due to second molar eruption
Correct answer: Combined width of primary canine and molars minus combined width of permanent canine and premolars
Leeway space is the difference between the combined mesiodistal width of the primary C, D, E (canine and two molars) and their permanent successors (C, PM1, PM2) — approximately 1.5 mm per side in the mandible.
Question 2: The normal overjet (horizontal overlap) in a Class I occlusion is approximately:
- 0 mm (edge-to-edge)
- 2–4 mm (Correct answer)
- 6–8 mm
- 1 mm or negative
Correct answer: 2–4 mm
Normal overjet in a Class I occlusion ranges from 2–4 mm, representing the horizontal distance between the facial surface of the lower incisors and the lingual surface of the upper incisors.
Question 3: Fluoride varnish application in pediatric patients is recommended beginning at:
- Birth (at the first well-child visit)
- Eruption of the first primary tooth (approximately 6 months) (Correct answer)
- Age 2 years
- Age 3 years when all primary teeth are erupted
Correct answer: Eruption of the first primary tooth (approximately 6 months)
The American Academy of Pediatric Dentistry (AAPD) recommends fluoride varnish application beginning at the eruption of the first primary tooth, approximately 6 months of age.
Question 4: A child presents with a completely avulsed permanent incisor. The best immediate storage medium before replantation is:
- Dry storage in a tissue or napkin
- Tap water
- Hank's Balanced Salt Solution (HBSS) or milk (Correct answer)
- Saline only
Correct answer: Hank's Balanced Salt Solution (HBSS) or milk
HBSS (save-a-tooth solution) is the gold standard storage medium; milk is the best readily available alternative due to appropriate osmolarity and nutrients that maintain PDL cell viability.
Question 5: The primary treatment for early childhood caries (nursing bottle caries) is:
- Immediate full-mouth extraction under general anesthesia
- Elimination of the cariogenic feeding habit, diet counseling, and restorative treatment of affected teeth (Correct answer)
- Prescription fluoride drops alone
- Watchful waiting until all primary teeth have erupted
Correct answer: Elimination of the cariogenic feeding habit, diet counseling, and restorative treatment of affected teeth
ECC treatment requires stopping the cariogenic behavior (nocturnal bottle feeding with fermentable carbohydrates), parent education, diet modification, and prompt restorative/preventive dental care.
Question 6: In orthodontic treatment, a headgear appliance with a cervical-pull (low-pull) force direction applies force that:
- Intrudes and retracts the maxillary molars vertically
- Distalizes and extrudes the maxillary molars, restraining forward maxillary growth (Correct answer)
- Protrudes the maxillary molars mesially
- Intrudes the maxillary incisors
Correct answer: Distalizes and extrudes the maxillary molars, restraining forward maxillary growth
A low-pull cervical headgear applies a downward and backward force on the maxillary molars, extruding and distalizing them while restraining forward maxillary skeletal growth.
DDS Orthodontics and Pediatric Dentistry 1
The leeway space (E-space) refers to the size difference between which groups of teeth?