Free NDEB Virtual OSCE Practice Questions

Sample Practice Questions

Try these 10 sample questions from the NDEB Virtual OSCE practice bank. Each includes the answer and explanation. Continue with the interactive practice above to review the full question set.

1. 1A vital permanent molar has an advanced cavitated dentin lesion and symptoms consistent with reversible pulpitis. A direct restoration is planned without pulp therapy. Which caries-removal strategy does the ADA guideline prioritize when it is feasible?

   1. A.Nonselective carious tissue removal
   2. B.Selective carious tissue removalCorrect answer: B
   3. C.Stepwise carious tissue removal
   4. D.No carious tissue removal

   Explanation: The guide states it "suggests prioritizing the use of selective carious tissue removal4 over stepwise carious tissue removal8 or non-selective carious tissue removal." This conditional recommendation applies to the vital permanent tooth requiring restoration without pulp therapy. It does not mean every clinical situation has the same preferred approach.

   Reference: ADA Chairside Guide: Restorative Treatments on Permanent Teeth — p. 1, advanced lesions recommendation

2. 2A patient has interdental attachment loss of at least 5 mm and has lost six teeth specifically because of periodontitis. Which stage is required by this tooth-loss severity criterion?

   1. A.Stage I
   2. B.Stage II
   3. C.Stage III
   4. D.Stage IVCorrect answer: D

   Explanation: The source states: "≥5 teeth" In the staging table, this threshold is in the Stage IV column. Six periodontitis-related losses cross that threshold; Stage III has at most four such losses, and Stages I–II have none.

   Reference: AAP/EFP Staging and Grading Periodontitis — p. 1, Staging table, tooth loss due to periodontitis

3. 3A large mixed red-white lesion on the lateral tongue is indurated and malignancy is in the differential diagnosis. The dentist is trained to obtain a representative diagnostic tissue sample. Which technique is the method of choice?

   1. A.Exfoliative cytology
   2. B.Incisional biopsyCorrect answer: B
   3. C.Excisional biopsy
   4. D.Fine-needle aspiration

   Explanation: The source states: "Incisional biopsy provides a representative sample of tissue for diagnostic purposes. It is the method of choice when the differential diagnosis includes malignancy." A representative incisional sample is appropriate. Cytology does not provide equivalent tissue architecture, excision is reserved for lesions almost certainly benign, and aspiration is not the standard sample for this mucosal lesion.

   Reference: JCDA Oral Soft-Tissue Biopsy: An Overview — Incisional Biopsy

4. 4A dentist explains how an injected local anesthetic prevents propagation of a pain impulse. Influx of which ion into the neural fiber is inhibited?

   1. A.Calcium
   2. B.Potassium
   3. C.SodiumCorrect answer: C
   4. D.Chloride

   Explanation: The source states: "Local anesthetics act within neural fibers to inhibit the rapid ionic influx of sodium necessary for neuron impulse generation and propagation." Sodium-channel inhibition interrupts the action potential. Calcium, potassium and chloride have genuine neural roles but are not the ion identified for this local-anesthetic mechanism.

   Reference: AAPD Use of Local Anesthesia for Pediatric Dental Patients — p. 407, Background

5. 5During dental care, an adult develops rapidly progressive wheeze, generalized hives and circulatory collapse after allergen exposure. Emergency services are activated. Which emergency medication should be administered promptly by the intramuscular route?

   1. A.Hydrocortisone
   2. B.Chlorphenamine
   3. C.Salbutamol
   4. D.EpinephrineCorrect answer: D

   Explanation: The source states: "Intramuscular adrenaline should be given (either self-administered or by trained individuals) as soon as possible via autoinjector into the outer thigh" Epinephrine (adrenaline) is the first-line intramuscular treatment for anaphylaxis. Antihistamines, corticosteroids and bronchodilators may address particular features but do not replace epinephrine.

   Reference: Resuscitation Council UK 2025 First Aid Guidelines — Medical emergencies, Anaphylaxis

6. 6A mandibular molar has spontaneous pain and cold pain that persists well after the stimulus is removed. The tooth responds to pulp testing and has no swelling. Which pulpal diagnosis best fits these findings?

   1. A.Reversible pulpitis
   2. B.Pulp necrosis
   3. C.Symptomatic irreversible pulpitisCorrect answer: C
   4. D.Previously initiated therapy

   Explanation: The AAE states, "Additional descriptors: lingering thermal pain, spontaneous pain, referred pain." Lingering thermal pain and spontaneous pain indicate symptomatic irreversible pulpitis. Reversible pulpitis should resolve; necrosis is pulp death, and previously initiated therapy requires prior partial endodontic treatment.

   Reference: AAE Consensus Conference Recommended Diagnostic Terminology — Pulpal: Symptomatic irreversible pulpitis, p. 1634

7. 7A patient has scratched the polished surfaces of an acrylic complete denture while cleaning it. Which cleaning product should the dentist recommend to limit further surface damage?

   1. A.An effective nonabrasive denture cleanserCorrect answer: A
   2. B.A silica-based whitening toothpaste for daily brushing
   3. C.A baking-soda cleaning powder for daily brushing
   4. D.A pumice-based polishing paste for daily brushing

   Explanation: The ACP states, "Dentures should be cleaned daily by soaking and brushing with an effective, nonabrasive denture cleanser." The nonabrasive cleanser avoids the abrasion associated with these alternative powders, dentifrices and polishing pastes. Product instructions must also be followed.

   Reference: ACP Evidence-Based Guidelines for Care and Maintenance of Complete Dentures — Guidelines, recommendation 2(a), p. S2

8. 8A primary molar with divergent roots requires extraction. Which force pattern best accommodates this anatomy while reducing root fracture risk?

   1. A.Firm continuous rotation around the tooth's long axis
   2. B.Rapid alternating rotation around the tooth's long axis
   3. C.Slow continuous buccal and palatal or lingual forcesCorrect answer: C
   4. D.Straight coronal traction without prior socket expansion

   Explanation: The source states, "Molar extractions are accomplished by using slow continuous palatal/lingual and buccal force allowing for the expansion of the alveolar bone to accommodate the divergent roots and reduce the risk of root fracture." Controlled buccolingual expansion accommodates divergent molar roots. Rotation suits conical single-root anatomy, and immediate traction lacks the stated controlled expansion.

   Reference: AAPD Management Considerations for Pediatric Oral Surgery and Oral Pathology — Maxillary and mandibular molars: Treatment considerations, p. 553

9. 9A child in the mixed dentition has a posterior crossbite with a reproducible functional mandibular shift on closure. What timing is recommended for correction of the shift?

   1. A.Correction after all permanent second molars have erupted
   2. B.Correction only after the pubertal growth spurt has ended
   3. C.Early correction as soon as possible after diagnosisCorrect answer: C
   4. D.Correction after completion of craniofacial skeletal growth

   Explanation: The AAPD states, "Functional shifts should be eliminated as soon as possible with early correction" Early correction reduces persistence of the functional asymmetry. Waiting for the listed later dental or growth milestones does not follow the recommendation.

   Reference: AAPD Management of the Developing Dentition and Occlusion in Pediatric Dentistry — Crossbites: Treatment considerations

10. 10An adolescent has a small noncavitated proximal enamel lesion. The dentist plans an adjunct to prevention that penetrates the porous lesion body with a low-viscosity resin. Which procedure is being planned?

    1. A.Resin infiltrationCorrect answer: A
    2. B.Enamel microabrasion
    3. C.Direct composite restoration
    4. D.Indirect pulp treatment

    Explanation: AAPD explains: "The aim of the resin infiltration technique is to allow penetration of a low viscosity resin into the porous lesion body of enamel caries." The intact proximal lesion fits infiltration. Microabrasion removes superficial enamel, a direct restoration replaces missing tissue, and indirect pulp treatment addresses deep dentin caries.

    Reference: AAPD Pediatric Restorative Dentistry — p. 475, Resin infiltration