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DANB ICE practice questions

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Question 1Infection Control Concepts and Standard Precautions

Standard precautions require that infection control measures be applied to which group?

  1. Only patients who report a history of bloodborne illness
  2. All patients, regardless of known or suspected infection Correct answer.
  3. Only patients whose test results are positive for a pathogen
  4. Only patients with visible oral lesions or bleeding

Explanation

Standard precautions are built on the premise that every patient may be carrying a bloodborne pathogen, so the same protective measures apply to everyone at all times. Medical history, appearance, and test results cannot reliably identify every infectious person.

Question 2Infection Control Concepts and Standard Precautions

During routine handwashing with soap and water, the hands should be rubbed together for at least how long?

  1. 5 seconds
  2. 60 seconds
  3. 20 seconds Correct answer.
  4. 10 seconds

Explanation

Current hand hygiene guidance calls for scrubbing all surfaces of the hands, including between the fingers and under the nails, for at least 20 seconds before rinsing. This duration allows adequate mechanical removal of transient organisms.

Question 3Infection Control Concepts and Standard Precautions

Which technique is recommended when a used needle must be recapped?

  1. Bending the needle first so it fits inside the cap
  2. Holding the cap in one hand while guiding the needle with the other
  3. Asking an assistant to hold the cap steady
  4. Using a one-handed scoop method on a flat surface Correct answer.

Explanation

Recapping is the leading cause of needlestick injuries, so recapping should be avoided whenever a safety device or nearby sharps container is available. When recapping is unavoidable, the one-handed scoop technique keeps the hand holding the cap out of the needle's path.

Question 4Infection Control Concepts and Standard Precautions

Which vaccine is recommended for all dental healthcare personnel who are not already immune?

  1. Herpes simplex vaccine
  2. Hepatitis B vaccine Correct answer.
  3. Hepatitis A vaccine
  4. Hepatitis C vaccine

Explanation

The Bloodborne Pathogens Standard requires employers to offer hepatitis B vaccination at no cost to employees with occupational exposure to blood. Immunity is documented by vaccination or by serologic testing.

Question 5Infection Control Concepts and Standard Precautions

When should heavy-duty utility gloves be worn instead of exam gloves?

  1. While performing a routine intraoral examination
  2. While taking a medical history at the front desk
  3. During direct patient care in the operatory
  4. While cleaning contaminated instruments Correct answer.

Explanation

Utility gloves are puncture-resistant and are intended for housekeeping tasks such as cleaning instruments and decontaminating surfaces. They may be cleaned and reused until torn or cracked, unlike single-use exam gloves.

Question 6Infection Control Concepts and Standard Precautions

If blood splashes into a clinician's eye, what is the recommended immediate action?

  1. Wait to see whether symptoms develop
  2. Rub the eye vigorously to dilute the blood
  3. Flush the eye with water or saline Correct answer.
  4. Apply antibiotic eye drops

Explanation

Mucous membrane exposures should be rinsed or flushed immediately with water or saline to reduce the infectious inoculum. The exposure is then reported so that source evaluation and post-exposure follow-up can begin.

Question 7Infection Control Concepts and Standard Precautions

Which sequence correctly describes putting on personal protective equipment before patient care?

  1. Gown, gloves, eyewear, mask
  2. Gloves, gown, mask, protective eyewear
  3. Mask, gloves, gown, protective eyewear
  4. Gown, mask, protective eyewear, gloves Correct answer.

Explanation

Gloves are donned last so they cover the gown cuffs and are not contaminated while the other items are being adjusted. Removal follows the reverse logic, with gloves coming off first while they are still the most contaminated item.

Question 8Infection Control Concepts and Standard Precautions

A sharps container should be replaced when it reaches what level of fullness?

  1. One-half full
  2. One-quarter full
  3. Completely full
  4. Three-quarters full Correct answer.

Explanation

Containers are closed and replaced when about three-quarters full so that sharps can still be dropped in without the hand reaching inside or items protruding over the rim. Overfilling is a common cause of container-related injuries.

Question 9Infection Control Concepts and Standard Precautions

Which situation requires handwashing with soap and water rather than an alcohol-based hand rub?

  1. Before gloving for a routine prophylaxis
  2. Before entering the treatment room
  3. After removing gloves following a non-surgical exam
  4. When hands are visibly soiled with blood or saliva Correct answer.

Explanation

Alcohol-based rubs cannot penetrate visible organic material, so soap and water is required whenever hands are visibly soiled and after restroom use. In all other routine situations an alcohol-based rub is preferred because it is faster and less drying.

Question 10Infection Control Concepts and Standard Precautions

Droplet precautions are indicated for a patient with which infection?

  1. Pulmonary tuberculosis
  2. Varicella (chickenpox)
  3. Seasonal influenza Correct answer.
  4. Measles

Explanation

Droplet precautions apply to organisms carried in large respiratory droplets that travel only a short distance, such as influenza, pertussis, and mumps. Tuberculosis, varicella, and measles are spread by airborne droplet nuclei and require airborne precautions with a fit-tested respirator.

Question 11Infection Control Concepts and Standard Precautions

What is the minimum level of processing required for a semicritical item such as a reusable mouth mirror?

  1. Low-level disinfection
  2. Intermediate-level disinfection
  3. High-level disinfection Correct answer.
  4. Hand scrubbing with soap and water

Explanation

Under the Spaulding classification, items that contact intact mucous membranes are semicritical and require high-level disinfection at minimum. Heat-tolerant semicritical items are usually sterilized instead because sterilization is simpler to verify.

Question 12Infection Control Concepts and Standard Precautions

How often should a steam sterilizer be monitored with a biological spore test?

  1. After each load
  2. Once a year
  3. Once a month
  4. At least weekly Correct answer.

Explanation

Biological monitoring with Geobacillus stearothermophilus spores is recommended at least weekly for steam sterilizers, plus after installation, repair, or any failed test. Process indicators and integrators are used in every load but do not replace spore testing.

Question 13Infection Control Concepts and Standard Precautions

Before beginning treatment each morning, dental unit waterlines should be flushed for at least how long?

  1. 20 to 30 seconds Correct answer.
  2. 10 minutes
  3. 2 minutes
  4. 5 seconds

Explanation

Flushing for 20 to 30 seconds at the start of the day and briefly between patients reduces the microbial load that accumulates in the lines overnight. Flushing alone does not meet the water quality standard and must be combined with an appropriate treatment system.

Question 14Infection Control Concepts and Standard Precautions

After visible blood has been removed from a contaminated surface, which product is appropriate for disinfecting the area?

  1. An ultrasonic cleaning solution
  2. Warm water rinse only
  3. A tuberculocidal hospital disinfectant Correct answer.
  4. Liquid instrument detergent

Explanation

Blood spills are first blotted up, then the surface is disinfected with an EPA-registered hospital disinfectant carrying a tuberculocidal claim, or with a 1:10 dilution of household bleach. Tuberculocidal potency demonstrates activity against the toughest organisms of concern in blood.

Question 15Infection Control Concepts and Standard Precautions

Which item must be discarded as regulated medical waste rather than ordinary trash?

  1. Exam gloves with no visible blood
  2. An empty local anesthetic cartridge
  3. A disposable paper cup used for rinse water
  4. A gauze saturated with blood Correct answer.

Explanation

Regulated waste includes items that are liquid or semi-liquid blood or other potentially infectious material, or that are caked with dried blood. Gauze saturated with blood meets that definition and must go into a labeled, closable container.

Question 16Infection Control Concepts and Standard Precautions

Immediately after a needlestick injury, what should the exposed clinician do first?

  1. Wash the site with soap and water and report the exposure Correct answer.
  2. Wait to report until the source patient's test results are known
  3. Squeeze the wound to force blood out and apply a tight bandage
  4. Apply bleach directly to the puncture and cover it with a bandage

Explanation

The puncture site is washed with soap and water (mucous membranes are flushed), and the exposure is reported at once so the source can be evaluated and prophylaxis started promptly. Confidential post-exposure follow-up is a required part of the exposure control plan.

Question 17Infection Control Concepts and Standard Precautions

A dental assistant with a documented latex allergy should be provided with which accommodation?

  1. Double gloving with two pairs of latex exam gloves
  2. Wearing latex gloves only during short appointments
  3. Taking an antihistamine tablet before each work shift
  4. Non-latex gloves and reduced latex exposure Correct answer.

Explanation

Employers must supply alternative gloves and reduce airborne latex protein, largely by eliminating powdered latex gloves. Continued exposure in a sensitized worker can progress to asthma or anaphylaxis.

Question 18Infection Control Concepts and Standard Precautions

Which of the following is a clinical contact surface in the operatory?

  1. The floor in the reception area
  2. The ceiling and walls of the treatment room
  3. The inside of the sterilizer chamber
  4. The dental light handle and bracket tray Correct answer.

Explanation

Clinical contact surfaces are touched by hands or contaminated instruments during patient care, such as light handles, bracket trays, switches, and drawer pulls. They are barrier-protected or disinfected between patients, while housekeeping surfaces receive routine cleaning.

Question 19Infection Control Concepts and Standard Precautions

Which element is required in an employer's written exposure control plan?

  1. Exposure evaluation and vaccination procedures Correct answer.
  2. A roster of patients known to be HBV or HIV positive
  3. The office's marketing and scheduling procedures
  4. A weekly schedule of staff meetings and breaks

Explanation

The written plan must describe exposure determination, methods of compliance, hepatitis B vaccination, post-exposure evaluation and follow-up, hazard communication, and recordkeeping. It is reviewed at least annually and whenever tasks or procedures change.

Question 20Infection Control Concepts and Standard Precautions

Which statement about single-use exam gloves is accurate?

  1. They never replace hand hygiene and are changed between patients Correct answer.
  2. They may be washed with alcohol rub and reused for the same patient
  3. They may be worn from the front desk into the operatory
  4. They protect the patient but not the clinician

Explanation

Gloves are a supplement to hand hygiene, not a substitute for it: hands are washed or rubbed before donning and after removing gloves. Gloves are removed between patients and whenever torn or heavily soiled.

Question 21Infection Control Concepts and Standard Precautions

An instrument that penetrates soft tissue or contacts bone falls into which Spaulding category, and what processing does it require?

  1. Semicritical; high-level disinfection
  2. Critical; cleaning followed by sterilization Correct answer.
  3. Noncritical; cleaning with a detergent disinfectant
  4. Noncritical; low-level disinfection

Explanation

Critical items such as forceps, scalers, surgical burs, and implant components enter sterile tissue or contact bone and must be cleaned and then sterilized. Semicritical items contact intact mucous membranes and require high-level disinfection at minimum.

Question 22Infection Control Concepts and Standard Precautions

What are the standard gravity-displacement steam sterilization parameters for a wrapped instrument load?

  1. 320 degrees F (160 degrees C) at 30 psi for 10 minutes
  2. 250 degrees F (121 degrees C) at 15 psi for 30 minutes Correct answer.
  3. 212 degrees F (100 degrees C) at 0 psi for 60 minutes
  4. 275 degrees F (135 degrees C) at 20 psi for 20 minutes

Explanation

Wrapped loads in a gravity-displacement sterilizer are typically processed at 250 degrees F (121 degrees C) and 15 psi for 30 minutes, while unwrapped items require roughly 15 minutes. Cycle times vary by unit, so the manufacturer's written instructions always govern.

Question 23Infection Control Concepts and Standard Precautions

Which sequence places these instrument-processing steps in the correct order? (1) package (2) transport to the processing area (3) sterilize (4) clean and dry (5) store

  1. 4, 2, 1, 3, 5
  2. 2, 4, 3, 1, 5
  3. 2, 1, 4, 3, 5
  4. 2, 4, 1, 3, 5 Correct answer.

Explanation

Contaminated instruments are transported, then cleaned and dried, then packaged, sterilized, and stored in a closed or covered area. Cleaning is the step that removes the greatest amount of bioburden and must precede packaging so debris cannot shield organisms from steam.

Question 24Infection Control Concepts and Standard Precautions

When removing personal protective equipment after patient care, which item is removed last?

  1. The mask or respirator Correct answer.
  2. The isolation gown
  3. The exam gloves
  4. The protective eyewear

Explanation

Gloves come off first because they are the most heavily contaminated, followed by eyewear and then the gown. The mask or respirator is removed last, by the straps only, after leaving the patient room, and hand hygiene follows immediately.

Question 25Infection Control Concepts and Standard Precautions

Post-exposure prophylaxis after an occupational HIV exposure should ideally begin within what time frame?

  1. Within one month of the exposure
  2. Only after the source patient tests positive
  3. Within hours, ideally no later than 72 hours Correct answer.
  4. Within two weeks of the exposure

Explanation

Prophylaxis should be started as soon as possible after exposure, ideally within hours; 72 hours is the outer limit recommended, and the regimen generally continues for 28 days. Earlier initiation is associated with better outcomes.

Question 26Infection Control Concepts and Standard Precautions

Standard precautions require that infection control measures be applied to which group of patients?

  1. Only patients scheduled for surgical procedures
  2. Only patients with visible oral lesions or bleeding
  3. Only patients who disclose a bloodborne infection
  4. Every patient, regardless of known infection status Correct answer.

Explanation

Standard precautions treat all blood, saliva, and other potentially infectious material as capable of transmitting disease, so they apply to every patient every time. Relying on a patient's disclosure or on visible signs would miss the many carriers who have no symptoms.

Question 27Infection Control Concepts and Standard Precautions

In the chain of infection, the disease-causing microorganism itself is called the:

  1. reservoir
  2. infectious agent Correct answer.
  3. portal of entry
  4. susceptible host

Explanation

The chain has six links: infectious agent, reservoir, portal of exit, mode of transmission, portal of entry, and susceptible host. The agent is the organism that causes disease; the reservoir is where it lives and multiplies.

Question 28Infection Control Concepts and Standard Precautions

When an alcohol-based hand rub is used for routine hand hygiene, the product should be applied and:

  1. rinsed off with warm water after 10 seconds
  2. wiped off with a paper towel while still wet
  3. left on the hands for at least 5 minutes before patient contact
  4. rubbed over all hand surfaces until the hands are dry Correct answer.

Explanation

Alcohol-based hand rub is dispensed into the palm and rubbed over all surfaces, including between the fingers, the thumbs, and the fingertips, until dry. Rinsing or wiping removes the product before the alcohol has had contact time to reduce organisms.

Question 29Infection Control Concepts and Standard Precautions

Which gloves are appropriate when cleaning contaminated instruments and handling disinfectant chemicals?

  1. Sterile surgical gloves
  2. Nonsterile exam gloves
  3. Heavy-duty utility gloves Correct answer.
  4. Vinyl exam gloves

Explanation

Utility gloves are thick, puncture- and chemical-resistant, and reusable after decontamination, which suits instrument cleaning and chemical handling. Exam and surgical gloves are thin, single-use, and easily torn by sharp edges or degraded by disinfectants.

Question 30Infection Control Concepts and Standard Precautions

If a needle must be recapped, the safest method is to:

  1. ask a co-worker to hold the cap steady
  2. guide the needle back into the cap slowly while watching it
  3. hold the cap in the fingers of the opposite hand
  4. use a one-handed scoop with the cap on a flat surface Correct answer.

Explanation

The one-handed scoop keeps both hands behind the needle so that a sudden movement cannot drive the needle into a finger. Recapping with two hands is the leading cause of needlestick injuries in dentistry and should be avoided entirely when possible.

Question 31Infection Control Concepts and Standard Precautions

A dental assistant wraps the air-water syringe and light handles with plastic film before treatment. This barrier should be:

  1. sprayed with disinfectant and reused for the next patient
  2. removed only if visible blood is present
  3. left in place for the whole day and replaced at closing
  4. removed and replaced between patients Correct answer.

Explanation

Barrier film protects clinical contact surfaces that are difficult to clean and is discarded and replaced whenever it is contaminated, at minimum between patients. Barriers are single-use; they are never disinfected and reused.

Question 32Infection Control Concepts and Standard Precautions

Food and beverages in the dental office are:

  1. allowed at the front desk if a lid is used
  2. allowed during breaks if gloves are not worn
  3. prohibited in the clinical area at all times Correct answer.
  4. allowed in the operatory if kept away from instruments

Explanation

Eating, drinking, and storing food are restricted to designated non-clinical areas because food, drink, and utensils can become contaminated with saliva or blood in treatment areas. This is a work practice control in the employer's exposure control plan.

Question 33Infection Control Concepts and Standard Precautions

An employer must offer the hepatitis B vaccine to employees with occupational blood exposure:

  1. only after the employee sustains a needlestick or other exposure incident
  2. only if the employee submits a written request during the annual training session
  3. only after the employee has completed 12 months of clinical employment
  4. at no cost, within 10 working days of assignment to exposure-prone duties Correct answer.

Explanation

The bloodborne pathogens standard requires that the vaccine be made available free of charge within 10 working days of initial assignment to tasks with exposure risk. An employee may decline, but must sign a declination form and may later change their mind.

Question 34Infection Control Concepts and Standard Precautions

A patient reports a chronic cough and a history of untreated pulmonary tuberculosis. Which precautions apply during treatment?

  1. Contact precautions with gown and gloves only
  2. Airborne precautions plus a fit-tested N95 respirator Correct answer.
  3. Standard precautions only, since only the mouth is treated
  4. Droplet precautions with a standard surgical mask for all staff

Explanation

Tuberculosis spreads by airborne droplet nuclei that stay suspended and travel on air currents, so a standard surgical mask does not filter them. A fit-tested N95 or higher respirator is required, and elective treatment is usually postponed until the patient is no longer infectious.

Question 35Infection Control Concepts and Standard Precautions

A clinician who wears an N95 respirator must be fit tested:

  1. only if the clinician reports a respiratory condition
  2. annually and whenever a new respirator model is worn Correct answer.
  3. once, at the time of initial hire
  4. whenever the respirator is removed between patients

Explanation

Fit testing verifies that a specific make, model, and size seals on the wearer's face, so it is repeated at least yearly and whenever the respirator changes. A user seal check is performed each time the respirator is donned but does not substitute for fit testing.

Question 36Infection Control Concepts and Standard Precautions

A patient has a draining skin lesion infected with MRSA and is scheduled for an extraction. In addition to standard precautions, the assistant should:

  1. place the patient in an airborne infection isolation room
  2. use droplet precautions and keep the door closed at all times
  3. add a gown and gloves and dedicate equipment to the patient Correct answer.
  4. wear an N95 respirator for the entire appointment

Explanation

Draining wound infections spread by direct and indirect contact, so contact precautions add a gown and gloves plus dedicated or thoroughly disinfected equipment. A mask or face shield may be added if splash is likely, but airborne isolation is not indicated.

Question 37Infection Control Concepts and Standard Precautions

Which statement about chemical indicators used in instrument processing is accurate?

  1. They prove that sterilization has occurred and replace spore testing.
  2. They detect the presence of blood and saliva on instruments.
  3. They show that the package was exposed to the process. Correct answer.
  4. They are used only for unwrapped instruments in a flash cycle.

Explanation

Chemical indicators respond to one or more parameters such as temperature, steam, or time and serve as process indicators confirming that the load went through the cycle. Only a biological indicator containing bacterial spores verifies that conditions were actually lethal.

Question 38Infection Control Concepts and Standard Precautions

Which practice is correct when loading a steam sterilizer?

  1. Pack the chamber as full as possible to save cycles
  2. Arrange packages loosely so steam can circulate Correct answer.
  3. Stack wrapped trays on top of one another
  4. Place all packages flat on the chamber floor

Explanation

Steam must contact every surface of every package, so items are placed loosely with space between them and nothing touching the chamber walls. Overloading, stacking, or laying packages flat traps air and prevents steam penetration.

Question 39Infection Control Concepts and Standard Precautions

Which practice is correct for an ultrasonic cleaner used to clean instruments?

  1. Reuse the same solution for one week before changing it.
  2. Leave the lid open so that the cavitation can be observed.
  3. Fill the unit with tap water only and omit the detergent.
  4. Keep the lid closed and change the solution at least daily. Correct answer.

Explanation

The lid limits the aerosolization of contaminated droplets created by cavitation, and the solution becomes soiled with organic debris. The unit is drained, cleaned, and refilled at least daily or sooner if visibly soiled, using the manufacturer's detergent.

Question 40Infection Control Concepts and Standard Precautions

How is a reusable heat-tolerant high-speed handpiece processed between patients?

  1. Soak in a high-level disinfectant for 10 minutes
  2. Wipe the exterior with an intermediate-level disinfectant only
  3. Clean and then sterilize by steam or chemical vapor Correct answer.
  4. Flush with water and apply a surface barrier

Explanation

Handpieces contact oral tissues and enter the category of items that must be sterile, and heat-tolerant models are cleaned and heat sterilized between patients. Manufacturer instructions for lubrication and internal flushing are followed before sterilization.

Question 41Infection Control Concepts and Standard Precautions

Before a vinyl polysiloxane impression is sent to the dental laboratory, it should be:

  1. sprayed with a high-level disinfectant and left wet
  2. rinsed in hot water and air dried
  3. placed in a biohazard bag without any treatment
  4. rinsed, disinfected per the manufacturer, and labeled Correct answer.

Explanation

Impressions carry saliva and blood, so they are rinsed, disinfected with a product compatible with the impression material, and placed in a container bearing the biohazard label. The manufacturer's instructions govern which disinfectant can be used without distorting the material.

Question 42Infection Control Concepts and Standard Precautions

A single-dose vial of local anesthetic that has been punctured for one patient should be:

  1. saved for the same patient's next appointment
  2. reused until the vial is empty
  3. used for that patient only and then discarded Correct answer.
  4. kept refrigerated for the next patient that day

Explanation

Single-dose vials contain no preservative and are intended for one patient only; leftover contents are discarded after the case. Multidose vials may be used for more than one patient only when accessed aseptically in a clean area away from the patient.

Question 43Infection Control Concepts and Standard Precautions

Which instruction to the patient helps prevent backflow from a saliva ejector into the mouth?

  1. Leave the ejector running with the chair in the upright position
  2. Have the patient bite down on the ejector tip
  3. Instruct the patient not to seal the lips tightly around it Correct answer.
  4. Attach the ejector to the lowest vacuum setting available

Explanation

Backflow occurs when a patient creates a tight seal with the lips around the ejector tip and pressure in the line equalizes, drawing oral fluids back through the device. An anti-retraction valve provides additional protection, and a saliva ejector is not a substitute for high-volume evacuation during fluid-heavy procedures.

Question 44Infection Control Concepts and Standard Precautions

For routine nonsurgical dental treatment, the recommended maximum heterotrophic bacterial count in dental unit water is:

  1. 500 CFU/mL Correct answer.
  2. 200 CFU/mL
  3. 1,000 CFU/mL
  4. 50 CFU/mL

Explanation

CDC and the ADA recommend that water used for nonsurgical care contain no more than 500 colony-forming units per milliliter of heterotrophic bacteria. Water used during surgical procedures must be sterile, such as sterile saline delivered through a sterile line.

Question 45Infection Control Concepts and Standard Precautions

Which feature is required of protective eyewear worn by clinical staff during patient care?

  1. Eyewear shared among staff and wiped between uses
  2. Tinted lenses to reduce the glare of the operating light
  3. Frames that are worn only when splatter is expected
  4. Side shields to protect against lateral splatter Correct answer.

Explanation

The eyes are a mucous membrane portal of entry, so protective eyewear with front and side protection is worn whenever splash, spray, or spatter may be generated. Patients are also given protective eyewear, and personal eyewear must be cleaned and decontaminated after use.

Question 46Infection Control Concepts and Standard Precautions

Which item is an engineering control for preventing sharps injuries?

  1. A policy that prohibits two-handed recapping
  2. A self-sheathing needle on an anesthetic syringe Correct answer.
  3. A posted sign giving the location of the exposure control plan
  4. An annual training session on safe sharps handling

Explanation

Engineering controls are devices that isolate or remove the hazard from the worker, such as self-sheathing needles, retractable syringes, and puncture-resistant sharps containers. Work practice controls change how a task is performed, while training and signage are administrative measures.

Question 47Infection Control Concepts and Standard Precautions

A steam sterilizer's biological spore test comes back positive. What is the appropriate response?

  1. Continue using the sterilizer but increase the exposure time by half
  2. Take the sterilizer out of service and recall items from recent loads Correct answer.
  3. Discard only the items in the failed load and resume routine use
  4. Repeat the test on the next scheduled monitoring day and continue normal use

Explanation

A positive spore test means the load may not be sterile, so the sterilizer is removed from service and items processed since the last negative test are quarantined or recalled. The unit is evaluated, repaired if needed, and rechallenged with biological indicators before it returns to patient use.

Question 48Infection Control Concepts and Standard Precautions

Which approach is recommended for instruments that may have contacted tissue from a patient with suspected Creutzfeldt-Jakob disease?

  1. Use disposable instruments and incinerate them after use Correct answer.
  2. Clean with an ultrasonic unit and package for routine sterilization
  3. Soak in a high-level disinfectant for 12 hours, then autoclave
  4. Sterilize twice in a standard gravity-displacement cycle

Explanation

Prions are extraordinarily resistant to routine cleaning, disinfection, and sterilization, so items that may have contacted high-infectivity tissue are handled as single-use and destroyed by incineration. Treatment is often deferred or referred so that a prion-specific protocol can be applied under the manufacturer's and public health guidance.

Question 49Infection Control Concepts and Standard Precautions

A dental hygienist completed the hepatitis B vaccine series, but a post-vaccination anti-HBs test shows no protective antibody. The employer should:

  1. Reassign the employee to duties that carry no exposure risk
  2. Consider the employee permanently immune and stop all follow-up
  3. Require the employee to receive the vaccine again every year
  4. Offer revaccination with a second series and retest the titer Correct answer.

Explanation

Employees who do not respond to the primary series are offered a second three-dose series and retested for anti-HBs. Persistent nonresponders are counseled about precautions and about the need for prompt evaluation and possible post-exposure treatment.

Question 50Infection Control Concepts and Standard Precautions

Which measure best reduces a clinician's exposure to microorganisms in aerosol produced during ultrasonic scaling?

  1. A surgical mask worn by the patient during treatment
  2. High-volume evacuation with a preprocedural rinse Correct answer.
  3. Keeping the operatory door open for ventilation
  4. Using a saliva ejector alone for the length of the appointment

Explanation

Ultrasonic and air-driven instruments generate the heaviest microbial aerosol in dentistry, and high-volume evacuation placed close to the working site captures most of it. A preprocedural antimicrobial rinse reduces the number of viable organisms released, and a rubber dam further limits contamination.