Free NDEB Assessment of Fundamental Knowledge (AFK) Practice Questions

Sample Practice Questions

Try these 10 sample questions from the NDEB Assessment of Fundamental Knowledge (AFK) practice bank. Each includes the answer and explanation. Continue with the interactive practice above to review the full question set.

1. 1What directly links frequent exposure to dietary sugars and starches with the initial mineral loss of dental enamel?

   1. A.Bacterial acid production at the tooth surfaceCorrect answer: A
   2. B.Neutralization of plaque acids by salivary buffers
   3. C.Mineral deposition from calcium-rich saliva
   4. D.Acid clearance through increased salivary flow

   Explanation: The source states "they form an acid.". Bacterial acid causes initial mineral loss. Buffering opposes acidic damage. Mineral deposition is remineralization. Clearance reduces acid exposure.

   Reference: NIDCR — Tooth Decay — Causes

2. 2Which component of a conventional dental implant system is inserted into the jawbone to replace the tooth root?

   1. A.Implant bodyCorrect answer: A
   2. B.Prosthetic crown
   3. C.Healing cap
   4. D.Impression coping

   Explanation: FDA states, "The dental implant body is surgically inserted in the jawbone in place of the tooth's root." The correct choice matches the stated mechanism or condition. The other choices misassign the relevant structure, process, material property or clinical consequence.

   Reference: FDA — Dental Implants: What You Should Know — Background

3. 3An unexplained red-and-white oral patch has persisted for three weeks. What is the appropriate response to this possible cancer warning sign?

   1. A.Wait for a routine recall in a year
   2. B.Arrange prompt professional assessment and indicated referralCorrect answer: B
   3. C.Treat it as harmless because it is not described as painful
   4. D.Assume a definitive diagnosis from its color alone

   Explanation: NIDCR states, "If you have any of these symptoms for more than two weeks, see a dentist or a doctor." Persistence beyond two weeks warrants assessment. Color alone does not establish a diagnosis, and absent pain does not justify delay.

   Reference: NIDCR — Oral Cancer — Symptoms

4. 4What bacterial process is directly inhibited by amoxicillin?

   1. A.Cell-wall biosynthesisCorrect answer: A
   2. B.Folate synthesis
   3. C.Ribosomal translocation
   4. D.DNA gyrase activity

   Explanation: The prescribing information states "inhibition of cell wall biosynthesis". Amoxicillin is a beta-lactam antibacterial that interferes with cell-wall formation, rather than the other antimicrobial targets.

   Reference: Amoxicillin Capsules — Official Prescribing Information (DailyMed) — 12.4 Microbiology — Mechanism of Action

5. 5How does the archwire in a fixed orthodontic appliance move teeth over time?

   1. A.By transmitting controlled pressure through bonded bracketsCorrect answer: A
   2. B.By holding teeth completely unloaded until they drift into alignment
   3. C.By using repeated chewing impacts as the main moving force
   4. D.By delivering one brief force at fitting without any subsequent loading

   Explanation: The NHS says the archwire can "apply a small amount of pressure". It transmits pressure through brackets over time. Passive unloading, repeated chewing impacts as the main force, and a single brief force without later loading do not explain controlled archwire action.

   Reference: NHS — Braces — How braces are fitted

6. 6How does persistent plaque contribute to periodontal tissue destruction?

   1. A.By exerting direct pressure that removes bone without inflammation
   2. B.By triggering inflammation in the gums and supporting tissuesCorrect answer: B
   3. C.By requiring infection to spread from the pulp as the first event
   4. D.By obstructing periodontal blood vessels as an intravascular plaque

   Explanation: NIDCR states "Plaque and tartar contain bacteria which can trigger inflammation that damages the gums and supporting tissues around the teeth, causing gum disease.". The bacterial biofilm provokes destructive inflammation. Direct pressure without inflammation misstates the mechanism, pulpal infection is not a required precursor, and dental plaque should not be confused with intravascular plaque.

   Reference: NIDCR — Periodontal (Gum) Disease — Causes

7. 7How should an avulsed permanent tooth be held while it is being handled for urgent dental care?

   1. A.By the apical end of the root
   2. B.By the middle of the root
   3. C.By the crownCorrect answer: C
   4. D.By scraping and gripping the root surface

   Explanation: The NHS guidance states "do not touch the root". Handle the tooth by its crown and avoid manipulating the root. The alternative grips all involve touching or damaging the root surface.

   Reference: NHS — Knocked-out tooth — What to do if a tooth has been knocked out

8. 8Which structures are found within the dental pulp?

   1. A.Only hydroxyapatite crystals and enamel rods
   2. B.Blood vessels and nervesCorrect answer: B
   3. C.Only keratinized epithelial cells
   4. D.Periodontal ligament fibers without vessels

   Explanation: The AAE states "blood vessels, nerves". The pulp is vascular and innervated soft tissue. Enamel rods belong to enamel, keratinized epithelium to surface tissue, and periodontal ligament lies outside the root.

   Reference: American Association of Endodontists — What Is a Root Canal? — What happens during root canal treatment?

9. 9Under CDC dental infection-control guidance, how should a reusable heat-tolerant surgical instrument that penetrates bone be processed between patients?

   1. A.Cleaned and wiped with a low-level surface disinfectant
   2. B.Cleaned and heat sterilizedCorrect answer: B
   3. C.Rinsed and stored in an open tray
   4. D.Cleaned and soaked in ordinary mouth rinse

   Explanation: The CDC states "They have the greatest risk of transmitting infection and should always be sterilized using heat.". An instrument that penetrates bone is a critical item. Cleaning followed by heat sterilization is required; surface wiping, rinsing, and mouth rinse do not achieve this standard.

   Reference: CDC — Sterilization and Disinfection in Dental Settings — Classifications — Critical items

10. 10Which mechanism can reverse the mineral deficit of a noncavitated enamel white-spot lesion?

    1. A.Formation of tertiary dentin along the pulpal wall
    2. B.Loss of enamel mineral during repeated acid challenges
    3. C.Mineral replenishment from saliva assisted by fluorideCorrect answer: C
    4. D.Mineral deposition within sclerotic dentinal tubules

    Explanation: The source states "Enamel can repair itself by using minerals from saliva and fluoride from toothpaste". Tertiary dentin forms internally, not in surface enamel. Acid challenges demineralize. Saliva and fluoride support enamel remineralization. Tubular sclerosis affects dentin rather than enamel.

    Reference: NIDCR — Tooth Decay — Causes