Free NDEB AFK practice questions with answers

Answer: B. About 3.9

2% lidocaine is 20 mg/mL, so one 1.8-mL cartridge holds 36 mg. The ceiling is 20 kg × 7 mg/kg = 140 mg, and 140 ÷ 36 ≈ 3.9 cartridges. In practice use the least volume that achieves anesthesia. Pediatric overdose most often comes from forgetting that the cartridge count shrinks with body weight.

Answer: B. Epinephrine 0.5 mg of 1 mg/mL solution intramuscularly

This is anaphylaxis: skin signs plus airway and circulatory compromise. Intramuscular epinephrine into the anterolateral thigh (0.01 mg/kg of 1 mg/mL, up to 0.5 mg in adults) is the first and time-critical drug, and it can be repeated every 5–15 minutes. Antihistamines and corticosteroids are adjuncts that do not reverse airway edema or hypotension. Salbutamol treats bronchospasm only.

Answer: B. Dentigerous cyst

A pericoronal radiolucency attached at the CEJ of an unerupted tooth is the classic presentation of a dentigerous cyst. The differential includes an enlarged follicle, an odontogenic keratocyst and a unicystic ameloblastoma, so the enucleated tissue must go for histopathology. A radicular cyst sits at the apex of a non-vital tooth.

Answer: D. Gorlin-Goltz syndrome

Multiple keratocysts at a young age should prompt a work-up for Gorlin-Goltz (nevoid basal cell carcinoma) syndrome, caused by PTCH1 mutation. Other features include basal cell carcinomas, palmar and plantar pits, bifid ribs and falx calcification. Gardner syndrome causes osteomas and supernumerary teeth. McCune-Albright causes polyostotic fibrous dysplasia with café-au-lait macules and endocrinopathy. Cowden syndrome causes multiple hamartomas, with papillomatous oral lesions.

Answer: B. Lactobacilli

Mutans streptococci are strongly linked to initiating enamel caries. Lactobacilli thrive in the acidic, retentive environment of an established cavity and are associated with progression in dentin. P. gingivalis and A. actinomycetemcomitans are periodontal pathogens. Current caries ecology frames the disease as a sugar-driven shift in the whole biofilm rather than one "caries germ".

Answer: B. 5.5

Below about pH 5.5 the plaque fluid is undersaturated for hydroxyapatite and enamel demineralizes. Fluorapatite has a lower critical pH (about 4.5), which is one reason fluoride present during pH cycling favors remineralization. Dentin and cementum demineralize at a higher pH (about 6.2–6.7), which is why root caries progresses readily.

Answer: B. Do not replant; assess the socket and monitor the successor

Avulsed primary teeth are not replanted. Replantation risks damaging the underlying permanent tooth germ and gives little benefit. Instead, check the socket and soft tissues, confirm the tooth is fully accounted for (not intruded or aspirated), give home-care advice and monitor the permanent successor. Permanent teeth, by contrast, are replanted as soon as possible.

Answer: E. Preformed stainless steel crown

Pulpotomized primary molars have lost significant structure and become brittle. A stainless steel crown gives full coverage and the best long-term seal and survival until exfoliation. Coronal leakage is a leading cause of pulp-therapy failure.

Answer: B. The rate of progression, adjusted for smoking and diabetes

Staging (I–IV) reflects severity and complexity: CAL, radiographic bone loss, tooth loss and treatment complexity. Grading (A–C) reflects the rate of progression: direct evidence, the bone-loss/age ratio, and case phenotype. Smoking and HbA1c act as grade modifiers. Extent (localized, generalized, molar-incisor pattern) is recorded as a descriptor.

Answer: C. Stage III

Interdental CAL of 5 mm or more and bone loss extending to the middle third or beyond indicate stage III or IV. Stage III allows tooth loss from periodontitis of up to 4 teeth. Stage IV applies with 5 or more teeth lost or a need for complex rehabilitation, such as masticatory dysfunction or secondary occlusal trauma. Staging and grading are assigned independently.

Answer: A. Cold milk

Replant immediately if possible. Otherwise use a physiologic medium: cold milk is widely available, and HBSS, saline or the patient’s saliva are alternatives. Water is hypotonic and lyses PDL cells. Drying is the worst option, since PDL survival falls sharply after about 30–60 minutes of dry time.

Answer: A. Anesthetic deposited too far posteriorly, into the parotid gland capsule

If the needle passes too far posteriorly, the solution can enter the parotid gland, where the facial nerve branches run. The result is transient ipsilateral facial paralysis. Reassure the patient, protect the eye (manual closure, patching and lubrication) until blinking returns, and document the event. It resolves as the anesthetic wears off.

Answer: A. A systematic review of randomized controlled trials

For therapy questions, systematic reviews (with meta-analysis where appropriate) of well-designed RCTs give the most reliable estimates of effect. Individual RCTs come next, then cohort and case-control studies, case series, and expert opinion. Always also judge risk of bias, directness and consistency, for example with GRADE, not only the design label.

Answer: B. 80%

Specificity = true negatives ÷ (true negatives + false positives) = 40 ÷ 50 = 80%. Sensitivity = 45 ÷ 50 = 90%. The positive predictive value is 45 ÷ 55 ≈ 82% and the negative predictive value is 40 ÷ 45 ≈ 89%. Unlike sensitivity and specificity, predictive values depend on how common the disease is.

Answer: C. Symptomatic irreversible pulpitis

Lingering pain after a thermal stimulus and spontaneous pain indicate symptomatic irreversible pulpitis, which is treated by pulpectomy (or, where appropriate, full pulpotomy) and root canal treatment. In reversible pulpitis the pain resolves within seconds and is never spontaneous. A normal periapex gives a periapical diagnosis of normal apical tissues.

Answer: C. Pulp necrosis; chronic apical abscess

Absent responses indicate necrosis. A gradual-onset, low-discomfort infection draining through a sinus tract with apical radiolucency is a chronic apical abscess. An acute apical abscess causes rapid-onset pain and swelling. Trace the sinus tract with a gutta-percha cone on a radiograph to confirm which tooth is the source.