Dental Assistant Practice Test

Dental Infection Control Practice Questions

Infection Control makes up 12 of every 50 questions on a Tigertest Dental practice test. Here are 10 of the 48 questions on it, each with the answer and the reason.

Updated 2026-11-10 by the Tigertest team. Weighted to the DANB GC, RHS (March 2025) and ICE (March 2025) outlines. Expanded functions vary by state.

1. 1. An assistant performs hand hygiene before gloving and after removing gloves. Which link in the chain of infection does this primarily break?

   • A.Virulence of the pathogen
   • B.Mode of transmission
   • C.Susceptible host
   • D.Reservoir of the agent

   Answer: B. Hand hygiene stops microbes from being carried from one person or surface to another, which breaks the mode of transmission. Vaccination, not hand washing, is what protects the susceptible host.

2. 2. An office manager wants to break the susceptible host link in the chain of infection for newly hired clinical staff. The most effective measure is:

   • A.Heat sterilizing handpieces
   • B.Changing masks between patients
   • C.Surface barriers on light handles
   • D.Hepatitis B vaccination

   Answer: D. Immunization makes the person resistant, removing the susceptible host link. Barriers, sterilization and mask changes interrupt the mode of transmission instead.

3. 3. A patient coughs during treatment and large droplets land on the assistant's face mask from about two feet away. This mode of transmission is:

   • A.Droplet transmission
   • B.Indirect contact transmission
   • C.Airborne transmission
   • D.Parenteral transmission

   Answer: A. Large droplets travel a short distance (about 3 to 6 feet) and land on mucosa or PPE, which is droplet transmission. Airborne spread involves tiny droplet nuclei that stay suspended and travel farther, like tuberculosis.

4. 4. An assistant is stuck by a contaminated scaler tip while unloading a tray. Disease spread through a break in the skin like this is called:

   • A.Airborne transmission
   • B.Indirect contact transmission
   • C.Parenteral transmission
   • D.Droplet transmission

   Answer: C. Parenteral means through the skin, as with needlesticks, cuts and bites, and is the main route for bloodborne pathogens. Droplet and airborne spread involve the respiratory tract, not penetration of skin.

5. 5. Dried blood remains on a counter overnight after a surgical case. Hepatitis B virus in dried blood on surfaces can remain infectious for up to:

   • A.10 minutes
   • B.1 hour
   • C.7 days
   • D.24 hours

   Answer: C. HBV is hardy and can survive in dried blood on environmental surfaces for about a week, which is why surfaces must be cleaned and disinfected. Assuming it dies within hours underestimates the risk.

6. 6. An unvaccinated assistant sustains a needlestick from a source patient carrying several bloodborne viruses. Which virus carries the highest risk of transmission?

   • A.Hepatitis B virus
   • B.Herpes simplex virus
   • C.Hepatitis C virus
   • D.Human immunodeficiency virus

   Answer: A. HBV is the most infectious bloodborne pathogen, with transmission risk after a needlestick far higher than for HCV or HIV (about 0.3% for HIV). Herpes simplex is spread mainly by contact with lesions, not by needlesticks.

7. 7. A patient scheduled for an elective cleaning reports a cough lasting three weeks, night sweats and weight loss. The dental team should:

   • A.Proceed wearing a surgical mask and face shield
   • B.Proceed using high-volume evacuation only
   • C.Proceed after a chlorhexidine preprocedural rinse
   • D.Defer care and refer for medical evaluation

   Answer: D. These are signs of active tuberculosis, which spreads by the airborne route, so elective treatment is postponed and the patient referred. A surgical mask does not protect against airborne droplet nuclei; an N95 respirator and isolation would be needed for urgent care.

8. 8. A patient arrives for a restorative appointment with an active, fluid-filled cold sore on the lower lip. The assistant should:

   • A.Rupture the vesicle and disinfect it first
   • B.Reschedule elective care until the lesion heals
   • C.Cover the lesion with petroleum jelly and proceed
   • D.Proceed using a rubber dam for isolation

   Answer: B. Active herpes lesions shed virus that can spread to the team or the patient's eyes and fingers, so elective care is deferred. Covering or isolating the lesion does not prevent spatter and contact with the infectious fluid.

9. 9. A new assistant has just completed the three-dose hepatitis B vaccine series. CDC recommends testing for antibody (anti-HBs) titer:

   • A.Only after an exposure incident
   • B.1 to 2 months after the series
   • C.Before the first dose only
   • D.Every year while employed

   Answer: B. Postvaccination testing 1 to 2 months after the series confirms immunity in health care workers. Routine yearly titers are not recommended, and waiting until an exposure leaves the worker's status unknown when it matters.

10. 10. A healthy-appearing new patient reports no medical conditions on the health history. Under standard precautions, the assistant should:

    • A.Use fewer barriers because the risk is low
    • B.Require blood test results before treatment
    • C.Wear gloves only if bleeding is expected
    • D.Treat as potentially infectious

    Answer: D. Standard precautions treat blood, body fluids, nonintact skin and mucous membranes of every patient as potentially infectious, because many carriers are unaware of infection. Reducing protection based on a history is exactly what standard precautions avoid.