Infection Control for Dental Assisting Exam Practice Problems

Practice Answers and Explanations

1. a. The definition of asepsis is being free of pathogenic microorganisms.

2. b. Sodium hypochlorite is the main ingredient in common household bleach.

3. c. The typical length of time for processing instruments using the autoclave is 30 minutes.

4. a. The chamber of an autoclave fills with water that is converted into steam when the chamber pressurizes.

5. b. A chemiclave differs from an autoclave in that water is not used. Instead, a chemical solution is pressurized, thereby sterilizing the instruments.

6. a. A semicritical instrument is one that comes in contact with soft tissue or bone but does not penetrate. An amalgam condenser comes in contact with the tooth but does not penetrate.

7. d. A critical instrument is an instrument that penetrates soft tissue or bone. Both a scalpel and a bur can penetrate soft tissue or bone. A gingival margin trimmer is used as a hand-cutting instrument on enamel or dentin and therefore does not penetrate soft tissue or bone.

8. c. A noncritical instrument is one that comes in contact with only intact skin. A Snap-A-Ray is an X-ray film-holding device that does not penetrate soft tissue or bone.

9. c. Alginate impressions are very sensitive. They need to be handled properly. Spraying with a disinfectant and then wrapping in a moist paper towel is the proper disinfecting technique.

10. a. Bioburden is made up of the patient’s blood, saliva, and other potentially infectious materials (OPIM).

11. e. The ultrasonic cleaner is used to pre-clean instruments. It loosens debris from the instruments using sound waves and is safer and more effective than scrubbing the instruments by hand.

12. e. Gluteraldehydes are very versatile in the dental office. They can be used for immersion disinfection and sterilization. They are strong enough to penetrate blood, saliva, and OPIM if exposed the proper length of time.

13. b. Biological monitoring is also known as spore testing. These tests are performed weekly to ensure proper sterilization function. A harmless spore strip is inserted into the sterilizer during a cycle, and then mailed to a laboratory where it is examined under a microscope. The technician is checking for sterilization.

14. b. Of all the blood-borne diseases, Hepatitis B is the most likely to be transmitted. It is transmitted through the air and is easily transmitted from patient to healthcare worker and from patient to patient.

15. b. Universal precautions is the act of treating all patients as if they are potentially infectious. This is an OSHA regulation.

16. a. Standard precautions is the act of developing a routine of dealing with disinfection and sterilization procedures within the dental office. A standard of care is developed where the dental assistant follows the same routine for each patient regarding the set-up and break down of the operatories, disinfection, and sterilization procedures.

17. e. PPE consists of lab coat, mask, eyewear, and gloves.

18. c. OSHA’s primary concern is the safety of the employee. The agency issues regulations to protect the employee from contracting an illness.

19. a. Gloves are the most critical PPE since the hands enter the patient’s mouth and are exposed to blood, saliva, and OPIM. The mask, eyewear, and lab coat are important but not as critical as the gloves.

20. b. The proper order of donning/performing PPE is lab coat, mask, eyewear, wash hands, and gloves. The gloves are donned last since they are the PPE that will be entering the patient’s mouth.

21. e. “Percutaneous” means through the skin. A needle or a sharp instrument can injure the healthcare worker by cutting the skin. Splash and spatter is considered to be a permucosal injury since it contacts the mucous membranes. PPE and observing care help prevent these injuries.

22. a. Occupational exposures are categorized depending on the location in the office where the professional works. Category I includes all healthcare workers who come into direct contact with blood, saliva, or OPIM. Professionals included in this category are the dentist, the chairside dental assistant, and the dental hygienist.

23. e. Utility gloves are recommended by OSHA, to be utilized when disinfecting dental operatory and when preparing contaminated instruments for sterilization. The hands are better protected during a critical exposure time.

24. c. Prior to sterilization, the high-speed hand piece should follow a pre-cleaning protocol. The hand piece should be run or flushed by stepping on the rheostat for 20 seconds prior to disconnecting it from the dental unit. This is done to eliminate any contaminated water from remaining in the hand piece. Next, the hand piece is brought into the sterilization area, and the outside of it is wiped down with either a disinfectant wipe or a 2 x 2 gauze soaked in alcohol. This is done to remove any bioburden since it is never recommended to immerse a hand piece in liquid of any kind. Finally, it is bagged and sterilized.

25. False. OSHA , not the dentist, determines the PPE worn by all dental professionals.

26. True. Manufacturers often recommend not overloading the sterilizer. It is believed that the instruments are not sterilized properly.

27. False. The ultrasonic cleaner removes bioburden via sound waves. The sound waves gently shake the instruments to remove the debris.

28. False. Cold sterilization is the use of gluteraldehyde in a holding container. In order for sterilization to be achieved, the instruments must be exposed to the solution for ten hours. Cold sterilization is used for instruments that cannot withstand heat or chemical sterilization.

29. False. Disinfection kills some but not all spores. Sterilization kills all spores.

30. False. According to OSHA regulations, a new employee must be offered the HBV series within ten days of employment. Failure to do so is a violation of OSHA regulations and puts the employee at risk.