Comprehensive Osteopathic Medical Licensing Examination (COMLEX) Level 1 — 100-Question Practice Exam with Answers and Rationales

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: