NBDE Knowledge 3 — Questions and Answers
Question 1: Which microorganism is most commonly associated with early childhood caries?
- Streptococcus mutans (Correct answer)
- Lactobacillus acidophilus
- Porphyromonas gingivalis
- Actinomyces viscosus
Correct answer: Streptococcus mutans
Streptococcus mutans is the primary pathogen in early childhood caries due to its acid production and ability to colonize tooth surfaces.
Question 2: Which of the following local anesthetics is classified as an amide?
- Lidocaine (Correct answer)
- Procaine
- Benzocaine
- Tetracaine
Correct answer: Lidocaine
Lidocaine is an amide-type local anesthetic metabolized by the liver, while procaine, benzocaine, and tetracaine are esters.
Question 3: The blood supply to the maxillary anterior teeth is primarily provided by which artery?
- Anterior superior alveolar artery (Correct answer)
- Posterior superior alveolar artery
- Greater palatine artery
- Infraorbital artery
Correct answer: Anterior superior alveolar artery
The anterior superior alveolar artery, a branch of the infraorbital artery, supplies the maxillary anterior teeth and surrounding tissues.
Question 4: In histology, the stratum granulosum of the oral epithelium is characterized by cells containing:
- Keratohyalin granules (Correct answer)
- Melanosomes
- Desmosomes only
- Mucous secretory granules
Correct answer: Keratohyalin granules
The stratum granulosum contains cells with basophilic keratohyalin granules that are precursors to the keratin filament matrix.
Question 5: Which vitamin deficiency is most associated with impaired wound healing and decreased collagen synthesis?
- Vitamin C (Correct answer)
- Vitamin D
- Vitamin A
- Vitamin K
Correct answer: Vitamin C
Vitamin C (ascorbic acid) is essential for hydroxylation of proline and lysine in collagen synthesis; its deficiency causes scurvy and impaired wound healing.
Question 6: Which suture type is preferred for intraoral soft tissue closure due to its minimal tissue reactivity?
- Polyglycolic acid (Dexon) (Correct answer)
- Plain gut
- Silk
- Cotton
Correct answer: Polyglycolic acid (Dexon)
Polyglycolic acid sutures are synthetic absorbable sutures with minimal tissue reactivity and predictable absorption, making them preferred intraoally.
Question 7: A patient taking warfarin has an INR of 3.8. What is the most appropriate management before a routine dental extraction?
- Consult with the patient's physician to adjust the anticoagulation (Correct answer)
- Proceed without modification
- Administer vitamin K injection pre-operatively
- Discontinue warfarin 5 days before the procedure
Correct answer: Consult with the patient's physician to adjust the anticoagulation
An INR above 3.5 requires physician consultation to safely adjust anticoagulation before dental extractions to minimize bleeding risk.
NBDE Knowledge 3
Which microorganism is most commonly associated with early childhood caries?