Question 1

What would be needed for a dental office to continue to perform restorations and give prophys under a "boil water notice?"

Accepted Answer

A)  A dry heat sterilizer and sterile treatment gloves
B)  An independent water reservoir on the dental units and an alcohol hand rub
C)  An unsaturated chemical vapor sterilizer and a high-level disinfectant
D)  Masks with attached face shields and barriers for all of the clinical contact surfaces in the operatory B

Question 2

Any water that passes through dental unit waterlines containing biofilm will become heavily contaminated.

Accepted Answer

A) True 
 B)False  True

Question 3

Why should you flush water through dental unit waterlines between patients?

Accepted Answer

A)  To remove all the biofilm in the waterlines
B)  To help lubricate the high-speed handpiece
C)  To sterilize the inside of the air-water syringe handle
D)  To temporarily lower the number of microbes in the water D

Question 4

Manufacturers of devices for the control of microbes in dental unit waterlines must be registered by _____before those chemicals can be legally marketed.

Accepted Answer

A)  the FDA
B)  the EPA
C)  the CDC
D)  OSHA

Question 5

Which of the following is a waterborne bacterium that can cause a harmful infection in compromised persons?

Accepted Answer

A)  Streptococcus mutans
B)  Legionella pneumophila
C)  Candida albicans
D)  Herpes simplex

Question 6

What is the main reason why relatively greater amounts of biofilm form in dental unit waterlines than in other types of waterlines?

Accepted Answer

A)  Because there are no microbes in any other type of waterlines
B)  Because water in dental units never contains any chlorine normally added at the water treatment plant
C)  Because the small diameter of these lines causes a high ratio of waterline surface to water volume
D)  Because the microbes in water are capable of attaching only to the material used to make dental unit waterlines

Question 7

Although waterborne microbes have been found in dental unit water, the vast majority of microbes present are human oral microbes.

Accepted Answer

A) True 
 B)False

Question 8

Current evidence indicates that there is a widespread public health problem from exposure to the microbes in dental unit water.

Accepted Answer

A) True 
 B)False

Question 9

How does biofilm in dental unit waterlines affect the microbial concentration in the water coming out of the dental unit?

Accepted Answer

A)  It may cause a decrease in the microbes in the water.
B)  It always causes a decrease in the microbes in the water.
C)  It does not affect the microbes in the water.
D)  It causes an increase in the microbes in the water.

Question 10

A "boil water notice" usually means that:

Accepted Answer

A)  boiling water should be used to sterilize contaminated instruments.
B)  the water should not be consumed or it should be boiled before use.
C)  the local water treatment plant has a problem and will boil all water before it is sent out to the city.
D)  you are not to boil the water because toxic materials got through the water treatment plant, and boiling the water will release these potentially harmful substances in the water vapor.

Question 11

The level of microbes in dental unit water is expressed as:

Accepted Answer

A)  mg/L.
B)  CFU/mL.
C)  ppm.
D)  µg/gal.

Question 12

Improvement in the microbial quality of dental unit water may involve use of an independent water reservoir, which is a(n):

Accepted Answer

A)  lake that supplies treated water to health care facilities for patient treatment.
B)  city water tower that supplies water to health care facilities for patient treatment.
C)  bottle attached to the dental unit that supplies the treatment water or other solutions.
D)  independent waterline from the city water treatment plant that is directly plumbed into dental units.

Question 13

When does the CDC recommend that dental unit waterlines with the attached handpiece should be flushed?

Accepted Answer

A)  Between every patient
B)  Once a day
C)  Once a week
D)  Every 10 minutes during an appointment

Question 14

What is the maximum number of microbes CDC says should be in dental unit water used for patient treatment?

Accepted Answer

A)  200,000 CFU/mL
B)  10,000 CFU/mL
C)  500 CFU/mL
D)  1 CFU/mL

Question 15

Water that meets the EPA standard for drinking is called _____ water.

Accepted Answer

A)  distilled
B)  deionized
C)  naturally filtered
D)  potable

Question 16

If using an independent water reservoir on a dental unit to deliver good quality treatment water, how often should the bottle be removed and cleaned?

Accepted Answer

A)  Daily
B)  Twice a week
C)  Weekly
D)  Monthly

Question 17

Planktonic microbes are microbes that:

Accepted Answer

A)  are free-floating in water.
B)  have been killed with a disinfectant.
C)  never multiply but remain dormant forever.
D)  form spores.

Question 18

If you attach a separate water bottle containing sterile water to a previously untreated dental unit with biofilm in its waterlines, what will the water quality be when it enters the patient's mouth?

Accepted Answer

A)  The water will be sterile.
B)  The water will contain microorganisms.
C)  The water will contain mercury.
D)  The water will be fluoride-free.

Question 19

What waterborne bacteria are of most concern in dentistry?

Accepted Answer

A)  Pseudomonas, Legionella, Mycobacterium
B)  Streptococcus, Staphylococcus, Bacillus
C)  Clostridium, Geobacillus, Porphyromonas
D)  Prevotella, Micrococcus, Serratia

Question 20

The level of microbes in water coming out of an unmodified dental unit is almost always:

Accepted Answer

A)  the same as drinking water.
B)  higher than drinking water.
C)  lower than drinking water.
D)  zero.

Exam 14: Dental Unit Water Asepsis and Air Quality