NBDE Trivia 5 — Questions and Answers
Question 1: Which drug interaction requires special consideration when prescribing metronidazole to a dental patient taking warfarin?
- Metronidazole decreases warfarin absorption
- Metronidazole inhibits CYP2C9 and potentiates warfarin's anticoagulant effect (Correct answer)
- Metronidazole accelerates warfarin metabolism
- Metronidazole displaces warfarin from albumin, reducing its effect
Correct answer: Metronidazole inhibits CYP2C9 and potentiates warfarin's anticoagulant effect
Metronidazole inhibits CYP2C9, slowing warfarin breakdown and raising INR, increasing bleeding risk.
Question 2: Which type of bone is found at the crest of the alveolar ridge, connecting the bundle bone of adjacent teeth?
- Cortical bone
- Cancellous bone
- Transseptal fiber bone (Correct answer)
- Lamellar bone
Correct answer: Transseptal fiber bone
Transseptal fibers embedded in the crestal bone form a continuous ligamentous connection between teeth across the interdental septum.
Question 3: In caries risk assessment, which factor is considered the single strongest predictor of future caries activity?
- Sugar intake frequency
- Past caries experience (Correct answer)
- Salivary flow rate
- Fluoride exposure
Correct answer: Past caries experience
Past caries experience (DMFT/dmft history) is the best single predictor of future caries risk in both children and adults.
Question 4: Which landmark on the mandible serves as the attachment site for the medial pterygoid muscle?
- Coronoid process
- Condylar head
- Pterygoid fovea
- Medial surface of ramus and angle (Correct answer)
Correct answer: Medial surface of ramus and angle
The medial pterygoid attaches to the medial surface of the mandibular ramus and angle, producing elevation and contralateral excursion.
Question 5: Which tooth surface is least susceptible to dental caries?
- Occlusal pits and fissures
- Proximal surfaces below the contact
- Smooth facial and lingual surfaces (Correct answer)
- Cervical areas near the gingival margin
Correct answer: Smooth facial and lingual surfaces
Smooth facial and lingual surfaces are self-cleansing and benefit most from fluoride, making them the least caries-susceptible surfaces.
Question 6: The term 'furcation involvement' refers to pathologic resorption of bone in which anatomical area?
- Root apex
- Alveolar crest
- Between the roots of multi-rooted teeth (Correct answer)
- Interdental septum of single-rooted teeth
Correct answer: Between the roots of multi-rooted teeth
Furcation involvement describes bone loss in the inter-radicular area (furcation zone) of multi-rooted teeth, classified by Glickman or Hamp scales.
Question 7: Which type of hypersensitivity reaction is responsible for allergic contact stomatitis from dental materials such as eugenol?
- Type I (IgE-mediated)
- Type II (cytotoxic)
- Type III (immune complex)
- Type IV (delayed/cell-mediated) (Correct answer)
Correct answer: Type IV (delayed/cell-mediated)
Allergic contact stomatitis to dental materials like eugenol or metals is a Type IV (delayed-type) hypersensitivity mediated by sensitized T-lymphocytes.
NBDE Trivia 5
Which drug interaction requires special consideration when prescribing metronidazole to a dental patient taking warfarin?