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AFK · Canada14 min read · September 25, 2026

AFK Practice Questions: 20 High-Yield Concepts With Explanations

Twenty practice questions, one from each of twenty dental branches, chosen because each tests a concept that turns up again and again in AFK preparation. Answer each one before opening the explanation, then use the concept line to check that you understand the idea, not just the answer.

By the Socket Science editorial team · Reviewed by a qualified dentist

Independent resource. DentistUP is not affiliated with or endorsed by any examination authority. Always check the official exam body for current format, dates and eligibility. Educational content, not patient-specific clinical advice.

How the AFK is built

The Assessment of Fundamental Knowledge is the first step of the NDEB Equivalency Process for internationally trained dentists who want to practise in Canada. According to the NDEB, it consists of 200 single-answer multiple-choice questions delivered in two parts, with two hours for each part. It covers biomedical science and applied clinical dental science.

Two features shape how you should practise. First, the AFK is broad: a weak branch cannot be hidden behind a strong one for long. Second, many questions test a precise distinction between two similar ideas, such as retention versus resistance form, or sensitivity versus specificity. The questions below were chosen to reflect both.

How to use this page

  • Cover the answer. Choose an option and note whether you were sure, fairly sure or guessing.
  • Open the explanation and read it even if you were right.
  • Read the concept line and check you could explain it to a colleague without looking.
  • For every guess or error, note the branch. Those branches are where your next study hours belong.

Part 1: Biomedical and basic sciences

Candidates who trained years ago often find the basic sciences the hardest part of the AFK, simply because they have not used them since dental school. These seven questions cover biochemistry, anatomy, embryology, pathology, microbiology, dental materials and biostatistics.

Question 1 · Biochemistry · Enamel/Dentin Mineral Chemistry

Fluorapatite forms when fluoride ions substitute for which component of the normal hydroxyapatite crystal?

  1. APhosphate groups within the crystal lattice
  2. BCalcium ions within the crystal lattice
  3. CCarbonate ions within the crystal lattice
  4. DHydroxyl groups within the crystal lattice
Show answer and explanation

Answer: D. Hydroxyl groups within the crystal lattice

In fluorapatite formation, fluoride ions replace hydroxyl groups within the hydroxyapatite crystal lattice. This substitution produces a more stable, less soluble crystal structure that is more resistant to acid dissolution than the original hydroxyapatite.

Concept to remember: Fluoride replaces hydroxyl groups to form fluorapatite, which is less soluble in acid than hydroxyapatite.

Question 2 · Head & Neck Anatomy · Cranial Foramina & Contents

The foramen rotundum primarily transmits which structure?

  1. AThe mandibular division of the trigeminal nerve instead of this one
  2. BThe maxillary division of the trigeminal nerve, its main content
  3. CThe middle meningeal artery and its accompanying vein structure
  4. DThe internal carotid artery as it enters the cranium at this level
Show answer and explanation

Answer: B. The maxillary division of the trigeminal nerve, its main content

The foramen rotundum is a round opening in the greater wing of the sphenoid bone that transmits the maxillary division of the trigeminal nerve (V2) from the middle cranial fossa into the pterygopalatine fossa, on its way to supplying the midface and upper teeth.

Concept to remember: Foramen rotundum carries V2; foramen ovale carries V3; foramen spinosum carries the middle meningeal artery.

Question 3 · Histology & Embryology · Craniofacial Embryology

A developing oral tissue shows an arch associated with glossopharyngeal nerve. Which structure or stage is identified?

  1. AFirst pharyngeal arch
  2. BLingual ankyloglossia
  3. CThird pharyngeal arch
  4. DSecond pharyngeal arch
Show answer and explanation

Answer: C. Third pharyngeal arch

Third pharyngeal arch is identified because it shows an arch associated with glossopharyngeal nerve; its principal role is formation of stylopharyngeus and part of the hyoid. Its microscopic appearance and developmental role distinguish it from adjacent oral tissues.

Concept to remember: Each pharyngeal arch has its own nerve: 1st V3, 2nd VII, 3rd IX, 4th and 6th X.

Question 4 · General Pathology · Genetics Relevant to Craniofacial Anomalies

Which pathologic process is defined by RUNX2 dysfunction causes patent sutures, hypoplastic clavicles, and delayed eruption?

  1. AAutosomal dominant inheritance: male-to-male transmission excludes X linkage and supports an autosomal dominant pedigree
  2. BCleidocranial dysplasia: normal intelligence with shoulder approximation reflects defective intramembranous ossification
  3. CAmelogenesis imperfecta: generalized thin or poorly mineralized enamel occurs without a necessary systemic bone disorder
  4. DDentinogenesis imperfecta: bulbous crowns and early pulpal obliteration accompany generalized blue-brown discoloration
Show answer and explanation

Answer: B. Cleidocranial dysplasia: normal intelligence with shoulder approximation reflects defective intramembranous ossification

Cleidocranial dysplasia is correct because it is characterized by RUNX2 dysfunction causes patent sutures, hypoplastic clavicles, and delayed eruption. This mechanism accounts for the defining pattern and separates it from alternatives that may share a clinical or microscopic feature but arise through a different pathologic pathway.

Concept to remember: Cleidocranial dysplasia (RUNX2): delayed eruption, supernumerary teeth, hypoplastic clavicles and open sutures.

Question 5 · Microbiology & Immunology · Biofilm Biology

Which organism commonly acts as a bridge between early and late plaque colonizers?

  1. AViridans streptococci — pioneer streptococcal adhesins permit attachment before bridging species arrive; early colonizers include Streptococcus sanguinis, S.
  2. BReduced activity of growth-dependent targets — metabolic dormancy creates phenotypic tolerance without a resistance mutation; many antibiotics act best on active biosynthesis or division.
  3. CFusobacterium nucleatum — broad adhesin compatibility links streptococci with later anaerobes; fusobacterium nucleatum coaggregates with numerous early and late colonizers.
  4. DStable multispecies spatial organization — a climax community persists through structured cooperation and nutrient exchange; mature plaque is not a random bacterial layer.
Show answer and explanation

Answer: C. Fusobacterium nucleatum — broad adhesin compatibility links streptococci with later anaerobes; fusobacterium nucleatum coaggregates with numerous early and late colonizers.

Fusobacterium nucleatum coaggregates with numerous early and late colonizers. This mechanism links fusobacterium nucleatum to the relevant microbial behavior, host response, or local ecological pressure. It also separates this process from clinically similar alternatives by identifying the decisive biologic feature.

Concept to remember: Fusobacterium nucleatum bridges early streptococcal colonisers and later anaerobes in plaque.

Question 6 · Dental Materials · Cements

Which property of conventional glass ionomer cement most supports its selection as a luting agent for a patient at high caries risk?

  1. ATolerance of moisture during setting
  2. BVery low film thickness
  3. CHigh compressive strength
  4. DSustained fluoride release
Show answer and explanation

Answer: D. Sustained fluoride release

Conventional GIC's sustained fluoride release provides an anticariogenic benefit at the restoration margin, making it favorable for high-caries-risk patients as a luting agent.

Concept to remember: Conventional glass ionomer bonds chemically to tooth and releases fluoride, which suits high caries risk.

Question 7 · Evidence-Based Dentistry & Biostatistics · Basic Biostatistics

A diagnostic test for early caries detection correctly identifies 18 of 20 patients who truly have the condition. What statistical property does this reflect?

  1. AHigh specificity in this case
  2. BHigh sensitivity in this case
  3. CHigh negative predictive value
  4. DLow prevalence in this case
Show answer and explanation

Answer: B. High sensitivity in this case

Sensitivity measures a test's ability to correctly detect people who actually have the condition, so correctly identifying 18 of 20 true cases reflects a high true positive rate, which is what sensitivity specifically captures among diseased individuals.

Concept to remember: Sensitivity is the proportion of people with the disease who test positive: true positives divided by all who have the disease.

If you missed more than two of these, plan dedicated time for the basic sciences early, while your clinical knowledge is still carrying most of your score. Our free head and neck anatomy diagrams are a quick way to rebuild spatial anatomy, and the histology and embryology questions and microbiology questions give you ten more in each area.

Part 2: Clinical dental sciences

The clinical questions below span anaesthesia, cariology, endodontics, prosthodontics, periodontics, oral pathology, oral medicine, oral surgery, radiology, orthodontics, pharmacology, infection control and ethics. Notice how often the right answer depends on one precise detail in the stem.

Question 8 · Anesthesia & Pain Control · Local Anesthesia: Complications

A hematoma after a posterior superior alveolar (PSA) injection is most often caused by which event?

  1. APuncture of the pterygoid venous plexus
  2. BAn overdose of the anesthetic solution
  3. CDirect trauma to the mandibular foramen
  4. DInjection into the parotid gland
Show answer and explanation

Answer: A. Puncture of the pterygoid venous plexus

The PSA injection site lies near the pterygoid venous plexus, a dense network of vessels that is easily punctured if the needle is advanced too far or angled incorrectly, leading to rapid blood accumulation in the surrounding soft tissue and visible facial swelling.

Concept to remember: PSA injections risk haematoma from the pterygoid venous plexus; avoid over-insertion.

Question 9 · Cariology & Operative Dentistry · Caries Process

A 5% sodium fluoride varnish contains approximately

  1. A12 300 ppm fluoride
  2. B5 000 ppm fluoride
  3. C22 600 ppm fluoride
  4. D1 450 ppm fluoride
Show answer and explanation

Answer: C. 22 600 ppm fluoride

5% sodium fluoride varnish contains approximately 22,600 ppm fluoride, a high concentration that allows effectiveness with just two to four applications per year on enamel.

Concept to remember: 5% NaF varnish contains about 22,600 ppm fluoride.

Question 10 · Endodontics · Pulp Biology & Pathology

A patient complains of sharp pain on cold water on tooth 2.5. The pain resolves immediately within 1-2 seconds after the cold stimulus is removed. What is the most likely pulpal diagnosis and appropriate management?

  1. AAsymptomatic irreversible pulpitis; perform a pulpotomy.
  2. BSymptomatic irreversible pulpitis; perform root canal treatment.
  3. CPulp necrosis; perform root canal treatment.
  4. DReversible pulpitis; remove caries/defective restoration and place a restoration.
Show answer and explanation

Answer: D. Reversible pulpitis; remove caries/defective restoration and place a restoration.

Reversible pulpitis is characterized by sharp, transient pain to thermal stimuli that ceases immediately after the stimulus is removed. It is managed by conservative restorative treatment.

Concept to remember: Sharp pain to cold that stops within seconds of removing the stimulus suggests reversible pulpitis.

Question 11 · Fixed Prosthodontics · Tooth Preparation Principles

In a complete crown tooth preparation, resistance form is primarily achieved by which preparation feature?

  1. AThe height and parallelism of opposing axial walls resisting displacement forces
  2. BThe presence of a clearly defined, deep finish line at the cervical margin
  3. CThe total occlusal convergence (taper) of the axial walls toward the occlusal
  4. DThe extent of axial surface area available for cement bonding
Show answer and explanation

Answer: A. The height and parallelism of opposing axial walls resisting displacement forces

Resistance form is provided by the height and near-parallelism of opposing axial walls, which prevent the restoration from being displaced or rotated by oblique occlusal forces. Taper relates to retention. Surface area influences cement retention, not resistance.

Concept to remember: Resistance form comes from wall height and near-parallelism; retention depends mainly on taper and surface area.

Question 12 · Periodontics · Non-Surgical Therapy

The primary objective of Scaling and Root Planing (SRP) in non-surgical periodontal therapy is best described as which of the following?

  1. ASurgically reflecting the gingival flap to allow direct visualization of calculus deposits
  2. BRemoving all cementum from the root surface to expose clean dentin for reattachment
  3. CPrescribing systemic antibiotics to sterilize the periodontal pocket environment chemically
  4. DEliminating viable bacteria and their toxic byproducts from root surfaces to promote healing
Show answer and explanation

Answer: D. Eliminating viable bacteria and their toxic byproducts from root surfaces to promote healing

SRP aims to mechanically disrupt and remove the subgingival biofilm, calculus, and endotoxin-contaminated cementum, creating a biologically clean root surface that allows healing and reattachment of periodontal tissues.

Concept to remember: Scaling and root planing aims to disrupt biofilm and remove calculus to allow healing, not to strip all cementum.

Question 13 · Oral Pathology · Non-Odontogenic Tumors & Fibro-Osseous Lesions of the Jaws

Because central giant cell granuloma is histologically indistinguishable from the brown tumor of hyperparathyroidism, which workup step is essential before treatment?

  1. AOrdering a complete blood count to exclude iron deficiency anemia as the underlying cause
  2. BObtaining serum calcium and parathyroid hormone levels to check for hyperparathyroidism
  3. CPerforming a sputum culture to exclude an underlying pulmonary tuberculosis infection
  4. DMeasuring fasting blood glucose levels to exclude poorly controlled diabetes mellitus
Show answer and explanation

Answer: B. Obtaining serum calcium and parathyroid hormone levels to check for hyperparathyroidism

Central giant cell granuloma and the brown tumor of hyperparathyroidism share an identical histologic appearance of multinucleated giant cells within a fibrocellular stroma, so serum calcium, phosphate, and parathyroid hormone testing is essential to rule out an underlying parathyroid disorder before local treatment.

Concept to remember: Central giant cell granuloma and brown tumour look the same under the microscope: check calcium and PTH.

Question 14 · Oral Medicine · Orofacial Infections: Medical Management Scope

Which finding is characteristic of primary herpetic gingivostomatitis?

  1. AA solitary painless white plaque that cannot be removed
  2. BOne recurrent ulcer limited to nonkeratinized labial mucosa
  3. CDiffuse gingivitis with widespread oral vesicles and ulcers
  4. DLocalized papillary necrosis without any mucosal lesions
Show answer and explanation

Answer: C. Diffuse gingivitis with widespread oral vesicles and ulcers

Primary oral HSV infection can produce fever, malaise, lymphadenopathy, diffuse painful marginal gingivitis, and vesicles that rapidly ulcerate across keratinized and nonkeratinized mucosa. This widespread pattern differs from recurrent herpes labialis and recurrent aphthae. Hydration status is central because pain may prevent drinking.

Concept to remember: Primary herpetic gingivostomatitis: fever, diffuse painful gingivitis and widespread vesicles that ulcerate.

Question 15 · Oral & Maxillofacial Surgery · Infections

A 24-year-old male patient presents to the clinic 48 hours after receiving an inferior alveolar nerve block (IANB) for a restorative procedure. The patient complains of severe, limited mouth opening (trismus) measuring 12 mm and mild pain, with no visible intraoral or extraoral swelling. Which of the following fascial spaces is most likely involved in this localized infection?

  1. ASubmasseteric space
  2. BSubmandibular space
  3. CSublingual space
  4. DPterygomandibular space
Show answer and explanation

Answer: D. Pterygomandibular space

Pterygomandibular space infection, often arising from contaminated needles during an IANB, leads to severe trismus due to inflammation of the medial pterygoid muscle, with minimal external swelling.

Concept to remember: Trismus without visible swelling days after an IANB suggests a pterygomandibular space infection.

Question 16 · Oral Radiology · Intraoral Radiographic Techniques

In the paralleling technique, how is the receptor positioned relative to the tooth's long axis?

  1. ADirectly against the root while the beam parallels the receptor
  2. BCurved around the crown while the beam enters from the occlusal plane
  3. CParallel to the long axis while the beam is perpendicular to both
  4. DPerpendicular to the long axis while the beam follows the root
Show answer and explanation

Answer: C. Parallel to the long axis while the beam is perpendicular to both

The paralleling technique places the receptor parallel to the tooth's long axis and directs the central ray perpendicular to both tooth and receptor. A holder and increased source distance help control geometry. The method generally gives more accurate dimensions than bisecting-angle projections when anatomy permits placement.

Concept to remember: Paralleling technique: receptor parallel to the long axis, central ray perpendicular to both.

Question 17 · Orthodontics · Orthodontic Treatment Biomechanics

Which orthodontic archwire delivers a light continuous force over a large range of activation?

  1. AStainless steel wire
  2. BBeta-titanium wire
  3. CCobalt-chromium wire
  4. DNickel-titanium wire
Show answer and explanation

Answer: D. Nickel-titanium wire

Nickel-titanium archwires have superelastic properties that deliver a relatively light, continuous force over a wide range of activation, making them ideal for initial alignment of severely displaced teeth.

Concept to remember: Nickel-titanium delivers light, continuous force over a wide activation range, useful for initial alignment.

Question 18 · Pharmacology · Analgesics & Anti-inflammatories

Why can appropriately dosed ibuprofen plus acetaminophen provide stronger post-operative analgesia than either drug alone?

  1. ADifferent mechanisms improve analgesia
  2. BIdentical receptors prevent tolerance
  3. CShared metabolism prevents toxicity
  4. DEqual half lives eliminate monitoring
Show answer and explanation

Answer: A. Different mechanisms improve analgesia

Ibuprofen reduces peripheral prostaglandin production, whereas acetaminophen acts mainly through central analgesic pathways. Combining complementary mechanisms can improve pain relief without relying on an opioid. Each component still retains its own dose ceiling, contraindications, and toxicity risks.

Concept to remember: Ibuprofen and acetaminophen act by different mechanisms; together they often outperform either alone.

Question 19 · Infection Control · Sterilization Methods

After a sterilization cycle, the autoclave printout shows the temperature never reached the programmed setpoint. What should the team conclude about that load?

  1. AUse the load since packaging looks intact
  2. BConsider the load sterile since the timer finished
  3. CCheck only the chemical indicator to confirm
  4. DTreat the load as nonsterile and reprocess
Show answer and explanation

Answer: D. Treat the load as nonsterile and reprocess

A mechanical indicator (printout, gauge, or digital readout) that shows a cycle parameter was not met is direct physical evidence the sterilization conditions were not achieved. Regardless of elapsed time or packaging appearance, that load must be considered unprocessed and reprocessed correctly.

Concept to remember: If the sterilizer printout shows a parameter was not met, the load is not sterile, whatever the packaging looks like.

Question 20 · Ethics & Law · Confidentiality & Records

A patient's employer contacts the practice requesting a copy of the patient's dental records without the patient's knowledge or consent. What is the appropriate response?

  1. ADecline to release records unless the patient has provided valid authorization
  2. BRelease a summary, since the employer has a general business interest at stake
  3. CRelease the full record, since employers may verify employee health information
  4. DRelease the records if the employer agrees to keep them informally confidential
Show answer and explanation

Answer: A. Decline to release records unless the patient has provided valid authorization

Patient records are confidential, and third parties, including employers, generally have no automatic right to access them. Absent a valid, patient-authorized release or a recognized legal exception, the practice should decline the request and inform the requester that authorization from the patient is required before any disclosure can occur.

Concept to remember: Records go to third parties, including employers, only with valid patient authorisation or a legal exception.

What your result tells you

Twenty questions cannot predict an exam result, but they can point to a pattern. Count your guesses as well as your errors:

  • Mostly confident and correct: your foundations are broad. Move on to full-length practice to test stamina and consistency.
  • Errors clustered in a few branches: work through those branches topic by topic before doing more mixed questions.
  • Many lucky guesses: this is the most common pattern and the most dangerous, because it feels like knowledge. Treat every guess as an error when you plan your study.

Turning a missed question into a fixed gap

A missed question is useful only if it changes what you know. After reviewing it, go to the topic behind it and answer a fresh set of questions on the same concept, ideally phrased differently. Return to the original question a few days later. If you can explain every option, the gap is closed; if not, the topic stays on your list. Our guide on why passive review fails explains the reasoning behind this approach, and how to pass the AFK on your first attempt puts it into a six-month plan.

Next step: a full-length mock

When you are ready for a longer test, the free 100-question AFK mock exam uses the same format as these questions across all major disciplines. You will see your score, the branches where you lost the most marks, and every explanation after you submit.

Frequently asked questions

How many questions are on the AFK?+

According to the NDEB, the AFK consists of 200 single-answer multiple-choice questions delivered in two parts, with two hours for each part. Check the NDEB website for current dates and delivery formats.

Are these official AFK questions?+

No. These are independently written practice questions from the DentistUP question bank. They are not official, recalled or leaked NDEB questions.

Which subjects does the AFK cover?+

The AFK tests biomedical sciences and applied clinical dental sciences. In practice that spans every major dental branch, from anatomy, biochemistry and microbiology to endodontics, periodontics, oral pathology, pharmacology and ethics.

How should I use these 20 questions?+

Answer each one before opening the explanation, note whether you were sure, and write down the concept in your own words. Any branch where you guessed or missed is a branch to study next.

Where can I find a full-length AFK practice exam?+

The free AFK mock exam on this site has 100 questions across all major disciplines, with every answer and explanation shown after you submit. No account is needed.

Free practice

Free 100-question AFK mockPharmacology questionsOral Pathology questionsPeriodontics questionsEndodontics questionsHead & Neck Anatomy questionsAll 29 branches →

DentistUP is an independent educational platform. Socket Science is not affiliated with, endorsed by, sponsored by, or approved by NDEB, INBDE, JCNDE, ADA, GDC, ORE, ADC, or any other examination authority. DentistUP does not contain official or recalled examination questions and does not guarantee examination outcomes.