NBDHE NBDHE Scientific Basis of Practice 2 — Questions and Answers
Question 1: Which nerve innervates the anterior two-thirds of the tongue for general sensation?
- Lingual nerve (V3) (Correct answer)
- Chorda tympani (VII)
- Glossopharyngeal nerve (IX)
- Hypoglossal nerve (XII)
Correct answer: Lingual nerve (V3)
The lingual nerve, a branch of V3, carries general somatic sensation from the anterior two-thirds of the tongue.
Question 2: Which immunoglobulin is the predominant antibody found in saliva and provides mucosal immunity?
- IgG
- IgM
- IgA (Correct answer)
- IgE
Correct answer: IgA
Secretory IgA is the dominant immunoglobulin in saliva and other mucous secretions, providing first-line mucosal defense.
Question 3: During tooth development, which process involves the differentiation of odontoblasts that then produce predentin?
- Initiation
- Histodifferentiation (Correct answer)
- Morphodifferentiation
- Apposition
Correct answer: Histodifferentiation
Histodifferentiation is the stage in which undifferentiated cells acquire specialized functions, including odontoblast differentiation leading to dentin formation.
Question 4: Warfarin inhibits which vitamin-dependent clotting factors?
- Factors I, V, VIII, XI
- Factors II, VII, IX, X (Correct answer)
- Factors VIII, IX, XI, XII
- Factors V, VIII, XI, XIII
Correct answer: Factors II, VII, IX, X
Warfarin blocks vitamin K epoxide reductase, impairing carboxylation of factors II, VII, IX, and X.
Question 5: Which bacterium is the primary etiologic agent of early childhood caries?
- Porphyromonas gingivalis
- Streptococcus mutans (Correct answer)
- Actinomyces viscosus
- Lactobacillus acidophilus
Correct answer: Streptococcus mutans
Streptococcus mutans is the principal pathogen in early childhood caries due to its acidogenicity and ability to colonize smooth surfaces.
Question 6: A patient taking phenytoin for epilepsy is most likely to exhibit which oral manifestation?
- Angular cheilitis
- Gingival enlargement (Correct answer)
- Black hairy tongue
- Geographic tongue
Correct answer: Gingival enlargement
Phenytoin-induced gingival enlargement (drug-influenced gingival overgrowth) is a well-known adverse effect of this anticonvulsant.
Question 7: Which type of collagen is the most abundant in the periodontal ligament?
- Type I (Correct answer)
- Type II
- Type III
- Type IV
Correct answer: Type I
Type I collagen is the predominant collagen of the periodontal ligament, providing tensile strength to anchor teeth.
NBDHE NBDHE Scientific Basis of Practice 2
Which nerve innervates the anterior two-thirds of the tongue for general sensation?