National Board Dental Examination
Part II (Legacy)
1. A patient presents with spontaneous, lingering pain to cold in a mandibular
molar. Radiograph shows no periapical pathology. The most likely diagnosis is:
A. Reversible pulpitis
B. Irreversible pulpitis
C. Pulp necrosis
D. Symptomatic apical periodontitis
Answer: B
Rationale: Lingering spontaneous pain to thermal stimuli without periapical
changes is characteristic of irreversible pulpitis.
2. The most common microorganism associated with root caries in elderly
patients is:
A. Streptococcus mutans
B. Actinomyces species
C. Lactobacillus acidophilus
D. Candida albicans
,Answer: B
Rationale: Actinomyces species are strongly associated with root surface caries
due to their affinity for cementum.
3. A working length radiograph shows an endodontic file 2 mm beyond the
apex. The most appropriate correction is to:
A. Increase file size
B. Increase working length
C. Shorten working length
D. Proceed with obturation
Answer: C
Rationale: Files beyond the apex indicate an excessive working length that must
be reduced to avoid periapical injury.
4. Which clasp type provides the greatest retention in a distal extension
removable partial denture?
A. Circumferential clasp
B. I-bar clasp
C. Ring clasp
D. Back-action clasp
Answer: B
Rationale: I-bar clasps engage undercuts effectively while minimizing torque on
abutment teeth in distal extension cases.
,5. The most common cause of failure in Class II amalgam restorations is:
A. Secondary caries
B. Marginal ditching
C. Fracture of restoration
D. Poor polish
Answer: C
Rationale: Amalgam is brittle, and bulk fracture due to inadequate thickness is
the most frequent cause of failure.
6. A patient taking bisphosphonates is at highest risk for developing:
A. Osteomyelitis
B. Medication-related osteonecrosis of the jaw
C. Alveolar osteitis
D. Fibrous dysplasia
Answer: B
Rationale: Bisphosphonates impair bone remodeling, predisposing patients to
medication-related osteonecrosis of the jaw (MRONJ).
7. The primary purpose of ferric sulfate in pediatric dentistry is to:
A. Disinfect dentin
B. Achieve hemostasis
C. Induce pulp calcification
D. Etch enamel
, Answer: B
Rationale: Ferric sulfate is a hemostatic agent commonly used in pulpotomy
procedures to control bleeding.
8. Which nerve provides sensation to the mandibular teeth?
A. Lingual nerve
B. Inferior alveolar nerve
C. Buccal nerve
D. Mental nerve
Answer: B
Rationale: The inferior alveolar nerve innervates mandibular teeth before
exiting as the mental nerve.
9. The most radiopaque dental material on a radiograph is:
A. Composite resin
B. Zinc oxide eugenol
C. Amalgam
D. Glass ionomer
Answer: C
Rationale: Amalgam contains metallic components that appear highly
radiopaque compared to other restorative materials.
10. A localized, purulent gingival lesion associated with a nonvital tooth is
termed:
Part II (Legacy)
1. A patient presents with spontaneous, lingering pain to cold in a mandibular
molar. Radiograph shows no periapical pathology. The most likely diagnosis is:
A. Reversible pulpitis
B. Irreversible pulpitis
C. Pulp necrosis
D. Symptomatic apical periodontitis
Answer: B
Rationale: Lingering spontaneous pain to thermal stimuli without periapical
changes is characteristic of irreversible pulpitis.
2. The most common microorganism associated with root caries in elderly
patients is:
A. Streptococcus mutans
B. Actinomyces species
C. Lactobacillus acidophilus
D. Candida albicans
,Answer: B
Rationale: Actinomyces species are strongly associated with root surface caries
due to their affinity for cementum.
3. A working length radiograph shows an endodontic file 2 mm beyond the
apex. The most appropriate correction is to:
A. Increase file size
B. Increase working length
C. Shorten working length
D. Proceed with obturation
Answer: C
Rationale: Files beyond the apex indicate an excessive working length that must
be reduced to avoid periapical injury.
4. Which clasp type provides the greatest retention in a distal extension
removable partial denture?
A. Circumferential clasp
B. I-bar clasp
C. Ring clasp
D. Back-action clasp
Answer: B
Rationale: I-bar clasps engage undercuts effectively while minimizing torque on
abutment teeth in distal extension cases.
,5. The most common cause of failure in Class II amalgam restorations is:
A. Secondary caries
B. Marginal ditching
C. Fracture of restoration
D. Poor polish
Answer: C
Rationale: Amalgam is brittle, and bulk fracture due to inadequate thickness is
the most frequent cause of failure.
6. A patient taking bisphosphonates is at highest risk for developing:
A. Osteomyelitis
B. Medication-related osteonecrosis of the jaw
C. Alveolar osteitis
D. Fibrous dysplasia
Answer: B
Rationale: Bisphosphonates impair bone remodeling, predisposing patients to
medication-related osteonecrosis of the jaw (MRONJ).
7. The primary purpose of ferric sulfate in pediatric dentistry is to:
A. Disinfect dentin
B. Achieve hemostasis
C. Induce pulp calcification
D. Etch enamel
, Answer: B
Rationale: Ferric sulfate is a hemostatic agent commonly used in pulpotomy
procedures to control bleeding.
8. Which nerve provides sensation to the mandibular teeth?
A. Lingual nerve
B. Inferior alveolar nerve
C. Buccal nerve
D. Mental nerve
Answer: B
Rationale: The inferior alveolar nerve innervates mandibular teeth before
exiting as the mental nerve.
9. The most radiopaque dental material on a radiograph is:
A. Composite resin
B. Zinc oxide eugenol
C. Amalgam
D. Glass ionomer
Answer: C
Rationale: Amalgam contains metallic components that appear highly
radiopaque compared to other restorative materials.
10. A localized, purulent gingival lesion associated with a nonvital tooth is
termed:
