Lecture 9

Question 1

Microorganisms colonize dental water lines forming_____ leading to contaminated water and aerosols

Answer 1

biofilms

Question 2

Biofilms

Answer 2

Microbial colones that adhere to solid surfaces in areas where there is sufficient moisture

Question 3

How many CFU/ml sets the level of Safe Water Drinking Act

Answer 3

500 CFU/ml

Question 4

What does CFU stand for?

Answer 4

Colony Forming Unit

Question 5

Where do the majority of microorganism come from ______

Answer 5

water source

Question 6

Some microorganisms come from ____-_____ device failure

Answer 6

anti-retraction

Question 7

What is an anti-retraction valve?

Answer 7

prevents back flow of fluid from patient into dental unit water line (DUWL)

Question 8

Failure of anti-retraction valve results in

Answer 8

allows retraction of fluid from patient #1 into the waterline, contaminating lines for patient #2

Question 9

Dental unit water vs Tap Water

Answer 9

Dental unit water-

• Very small diameter tubing
• Very slow flow rate-drips
• hydrophobic tubing makes biofilm attachment easy
• Left stagnant for hours
• Chlorine dissipates over 24 hrs

Tap Water-

• 1/2” diameter
• 5 liters/minutes= 1000X dental flow
• copper is antimicrobial and bacteriostatic
• Line is flushed with fresh water frequently
• Chlorinated at every use

Question 10

How do microbes in DUWL- surfaces begin colonization

Answer 10

Minerals found in water are deposited on surface which help bacteria to adhere

Question 11

As the diameter of the tubing ______ the surface area covered by biofilm increases. At the same time, the volume of water passing by ____

Answer 11

decreases; decreases

Question 12

What percent of Legionellosis in a dentists’ blood is considered occupational exposure

Answer 12

5%

Question 13

What are symptoms of Legionellosis

Answer 13

• Flu like symptoms called Pontiac Fever
• pneumonia

Question 14

Legionnaires’ Disease is caused by what bacteria

Answer 14

Legionella

Question 15

Legionnaires’ Disease affects primarily the _____

Answer 15

lungs

Question 16

How is Legionnaires’ Disease transmitted?

Answer 16

aerosols of water NOT PERSON TO PERSON

Question 17

Environment for growth of Legionella

Answer 17

stagnation

Question 18

Unless something has been done to treat the DUWL, it should or should not be assumed that the water is contaminated

Answer 18

assumed

Question 19

What three things can be done to help prevent exposing tools to contaminated water

Answer 19

• flush water through the lines
• independent reservoirs
• chemically treat water