NBDE Knowledge 2 — Questions and Answers
Question 1: Which type of collagen is predominantly found in the periodontal ligament?
- Type I (Correct answer)
- Type II
- Type III
- Type IV
Correct answer: Type I
Type I collagen is the major collagen in the periodontal ligament, providing tensile strength.
Question 2: The foramen cecum of the tongue marks the site of origin of which structure?
- Thyroglossal duct (Correct answer)
- Wharton's duct
- Stensen's duct
- Sublingual gland
Correct answer: Thyroglossal duct
The foramen cecum is the embryologic remnant of the thyroglossal duct from which the thyroid gland descended.
Question 3: Which pharmacological agent is most appropriate for reversing benzodiazepine overdose?
- Flumazenil (Correct answer)
- Naloxone
- Atropine
- Physostigmine
Correct answer: Flumazenil
Flumazenil is a competitive benzodiazepine receptor antagonist used to reverse benzodiazepine sedation.
Question 4: Which cell is primarily responsible for bone resorption?
- Osteoclast (Correct answer)
- Osteoblast
- Osteocyte
- Fibroblast
Correct answer: Osteoclast
Osteoclasts are multinucleated cells derived from hematopoietic precursors that resorb bone via acid and proteolytic enzymes.
Question 5: A patient presents with inability to open the mouth widely after a mandibular block injection. This complication is best described as:
- Trismus (Correct answer)
- Ankylosis
- Myofascial pain
- Subluxation
Correct answer: Trismus
Trismus is limited mouth opening due to muscle spasm or injury, often following inadvertent injection into the medial pterygoid muscle.
Question 6: The process of apposition in tooth development refers to:
- Layered deposition of enamel and dentin matrices (Correct answer)
- Initiation of the tooth bud
- Histodifferentiation of ameloblasts
- Eruption of the tooth into the oral cavity
Correct answer: Layered deposition of enamel and dentin matrices
Apposition is the stage in tooth development where enamel and dentin matrices are incrementally laid down by ameloblasts and odontoblasts.
Question 7: Which nerve provides general somatic afferent innervation to the anterior two-thirds of the tongue?
- Lingual nerve (V3) (Correct answer)
- Glossopharyngeal nerve (CN IX)
- Hypoglossal nerve (CN XII)
- Chorda tympani (CN VII)
Correct answer: Lingual nerve (V3)
The lingual nerve, a branch of V3, carries general sensation (touch, temperature, pain) from the anterior two-thirds of the tongue.
NBDE Knowledge 2
Which type of collagen is predominantly found in the periodontal ligament?