Sterilization and Antisepsis

Question 1

What are the routes of transmission during dental treatment?

Answer 1

1. direct contract with infectious lesions, saliva, or blood
2. indirect transmission via contaminated intermediate object
3. spatter of blood, saliva, plaque or nasopharyngeal secretions
4. Aerosolization of blood, saliva, plaque or nasopharyngeal secretions

Question 2

What is the fatality rate for Ebola?

Answer 2

50%, young and elderly associated with higher fatality rates

Question 3

T/F. Ebola is highly infectious and takes a large load to infect.

Answer 3

False, Ebola is highly infectious BUT a miniscule amount (1 virus particle) may be enough to infect.

Question 4

T/F. Ebola is only moderately contagious and is transmitted by direct contract with body fluids from infected person or contaminated objects from infected persons (fomites).

Answer 4

True

Question 5

T/F. Ebola is transmitted by air.

Answer 5

False, acquired via direct contact through broken skin or mucous membranes

Question 6

How long is the incubation period for Ebola?

Answer 6

2 - 21 days

Question 7

When does an Ebola patient become contagious?

Answer 7

when symptoms develop

Question 8

The Ebola virus is ___ so it can be killed or inactivated by ___ hand sanitizer.

Answer 8

Enveloped; alcohol

Question 9

Is the risk of transmission of HIV from a health care worker to a patient low or high? What about from a patient to health care provider?

Answer 9

low

low occupational risk

Question 10

T/F. Standard infectious control practices are highly effective against HIV and the risk from percutaneous exposure is 3 to 4 per 1000 exposures.

Answer 10

True.

Question 11

Is immediate post exposure anti-retroviral therapy effective against HIV?

Answer 11

yes

Question 12

Hepatitis B has ____ persons infected each year, ___% of infections that go undiagnosed and ___ million carriers.

Answer 12

300,000; 80; 1

Question 13

T/F. There are a few cases of Hep B transmission from and to health care workers.

Answer 13

False, there are MANY documented cases of transmission to and from health care workers.

Question 14

T/F. Most health care workers are vaccinated against Hep B.

Answer 14

True

Question 15

There is an ___ resurgence of TB and the risk during dental procedures appears to be ___.

Answer 15

TB; low

Question 16

TB patients that ___ produce infective aerosols that are not transmitted by ___ contamination but must be ___.

Answer 16

cough; surface; inhaled

Question 17

Which virus is frequently present in the oral cavity and may be transmitted to health care workers?

Answer 17

Herpes I and II

Question 18

___ herpes may cause blindness and viral ___ is when the herpes lesion appears on the finger.

Answer 18

Ocular; whitlow

Question 19

Which immunizations are recommended for health care providers by the CDC?

Answer 19

Hep B
Influenza
Measles
Mumps
Rubella
Varicella zoster

Question 20

___ items come into contact with tissue or the vascular system. Give an example.

Answer 20

Critical

surgical instruments (needles, dental burs, endo)

Question 21

___-___ items come into contact with mucous membranes or non-intact skin. Give an example.

Answer 21

Semi-critical

curing light

Question 22

___ items touch intact skin. Give an example.

Answer 22

Noncritical

blood pressure cuff

Question 23

Define sterilization, disinfectants, and antiseptics

Answer 23

Sterilization: destruction or removal of all forms of life including spores. Can be heat or chemical. Not used on humans - only inanimate objects.

Disinfectants: Inhibition or destruction of pathogens (spores not killed). Only used on inanimate objects.

Antiseptics: destroy pathogenic microorganisms on living tissues and are safe for use on human tissues (soap)

Question 24

___ registers environmental surface disinfectants based on the manufacturer’s ___ activity claims when registering its disinfectant.

Answer 24

EPA; microbiological

Question 25

FDA regulates ___ chemical sterilants used on ___ and __-___ devices. EPA regulates ___ used on ___ surfaces and ___ sterilants.

Answer 25

liquid; critical; semi-critical; disinfectants; noncritical; gaseous

Question 26

___-level disinfection destroys all microorganisms, with the exception of bacterial spores. ___-level disinfection inactivates ___ ___, vegetative bacteria, most viruses, and most fungi but it does not kill bacterial spores. ___-level disinfection kills most bacteria, some viruses and some fungi, but it cannot be relied on to kill ___ microorganisms such as ___ ___ or bacterial ___.

Answer 26

High Intermediate; Mycobacterium tuberculosis Low; resistant; Mycobacterium tuberculosis; spores

Question 27

Why must critical items be sterilized?

Answer 27

because they enter sterile tissue or the vascular system and any microbial contamination could transmit disease

Question 28

How are semi-critical and noncritical items cleaned?

Answer 28

Semi-critical: sterilize if possible, high or intermediate-level disinfection required Noncritical: low-level disinfectant

Question 29

Why is heat sterilization the most efficient and reliable method?

Answer 29

proteins are denatured by heat, thus killing organisms

Question 30

What are the autoclave conditions?

Answer 30

``` steam under pressure 121oC (250oF) 15psi 15-20 minutes packing material must allow for penetration of steam (paper, plastic cloth - not closed metal or glass containers) ```

Question 31

What are the advantages and disadvantages to steam sterilization?

Answer 31

advantages: short cycle time, good penetration disadvantages: - corrosion (oxidation) of unprotected carbon steel & dulling of cutting edges - deposits from hard water (use distilled) - may remain wet at end of cycle - destruction of heat sensitive materials

Question 32

How can corrosion and dulling of instruments be prevented when under steam pressure?

Answer 32

with 1% sodium nitrite solution

Question 33

T/F. Flash steam sterilization has a lower temperature and pressure than autoclave.

Answer 33

False, Flash steam sterilization has a HIGHER temperature and pressure than autoclave.

Question 34

For dry heat sterilization, ___ proteins are more stable, so ___ temp and ___ time is required. The heat transfer is ___, so oven cannot be overfilled, and packages must be kept small.

Answer 34

dehydrated; high; longer; slow

Question 35

Does dry heat sterilization corrode or dull cutting edges?

Answer 35

No

Question 36

What are the disadvantages of using dry heat sterilization?

Answer 36

long cycle may discolor or char fabric destruction of heat sensitive materials (rubber/plastic destroyed) (soldered impression trays melt) unsuitable for handpieces

Question 37

What is a forced air unit that reduces heat transfer time?

Answer 37

rapid heat transfer sterilization

Question 38

What are the advantages and disadvantages to rapid heat transfer sterilization?

Answer 38

Advantages: 1. short cycle 2. dry at end 3. does not corrode or dull Disadvantages 1. instruments must be dry at start 2. destruction of health labile items 3. not suitable for handpieces 4. unwrapped items not protected after cycle

Question 39

What is used to create the sterilizing vapor for Chemiclave?

Answer 39

Depends on heat, water and chemical synergy Mixture of methyl alcohol, formaldehyde, ketone, acetone and water

Question 40

T/F. Penetration of Chemiclave is as good as steam.

Answer 40

False, no it is not so items must be loosely packed and dry.

Question 41

What are the advantages and disadvantages of Chemiclave?

Answer 41

Advantages: short cycle time, does not corrode or dull cutting edges Disadvantages: chemical odor & safety concerns, instruments must be dried before use, chemical solution required, heat-sensitive materials may be destroyed

Question 42

Who monitors sterilization?

Answer 42

CDC and Ohio state law

Question 43

Chemical treated ___ and heat sensitive ___ indicate that a package has been heated, but not that sterilization temperatures were reached or held for adequate period of time.

Answer 43

tapes; strips

Question 44

T/F. Some indicators change color long before sterilization conditions are met.

Answer 44

True, they do not ensure adequacy of sterilization cycle (especially autoclave tape)

Question 45

What provides the best guarantee of sterilization?

Answer 45

biological indicators

Question 46

Which two microorganisms contain spores that are more resistant than viruses or vegetative forms of bacteria?

Answer 46

``` bacillus stearothermophilus (autoclaves and chemiclaves) bacillus subtilis (dry heat) ```

Question 47

What are the two forms of biological monitors?

Answer 47

1. glass vials containing suspensions of spores plus pH indicator (if spores germinate or produce acid, color change can be seen) 2. spore-impregnated strips in glassine envelopes must be sent to service for checking.

Question 48

T/F. It is ok to use chemical sterilants instead of heat.

Answer 48

False.

Question 49

Ethylene oxide (ETO) is an ___ agent that irreversibly inactivates nucleic acids and proteins. It is an explosive gas mixed with ___ and will ___ tissue.

Answer 49

alkylating; freon; burn

Question 50

T/F. ETO damages heat or moisture labile materials and leaves a residue after adequate aeration.

Answer 50

False, ETO DOES NOT damage heat or moisture labile materials and DOES NOT leave a residue after adequate aeration.

Question 51

What are the disadvantages of ETO?

Answer 51

slow hazardous material (toxic, carcinogenic and explosive) items must be clean and dry retained in liquid and rubber items for a long time toxic residue if not well aerated

Question 52

What is the most potent chemical germicide that is active in the presence of organic debris?

Answer 52

Glutaraldehydes

Question 53

What are the disadvantages to glutaraldehydes?

Answer 53

``` long immersion time rinsing required severe tissue irritation and toxicity from fumes allergenic biologically non-verifiable cannot package items corrosive to metals ```

Question 54

CaviWipes are a combination of ___ and ___ ___ solutions. It is an ___-level disinfectant for __-___ items (in contact with intact mucous membranes)

Answer 54

alcohol; quaternary ammonium; intermediate; semi-critical

Question 55

T/F. Accelerated Hydrogen Peroxide (AHP) is a combo of 0.5% hydrogen peroxide surfactants, chelating agents and wetting agents.

Answer 55

True

Question 56

Phenols and derivatives are ___ poisons that penetrate and disrupt microbial cell walls and denature intracellular proteins. They are not suitable as ___, and must be used in conjunction with another agent.

Answer 56

cytoplasmic; antiseptics

Question 57

T/F. Phenols are EPA registered surface disinfectant with broad spectrum but not sporicidal. They have been replaced by quaternary ammonium-alcohol combo agents.

Answer 57

True.

Question 58

What are the two single unit alcohols?

Answer 58

70% ethyl alcohol | 70% isopropyl alcohol

Question 59

Alcohol solutions containing ___% alcohol are most effective. Higher concentrations of alcohol produced even greater ___ and ___ surface disinfection.

Answer 59

60-80; dehydration; poorer

Question 60

What is the antimicrobial effect of alcohols?

Answer 60

the effect results from denaturation of proteins and dissolution of lipid membranes.

Question 61

What are the disadvantages of alcohols?

Answer 61

alcohol dehydrates proteins, making them insoluble and tenaciously adherent to surfaces. Denatured bioburden can protect contaminant microorganisms -rapid evaporation results in rapidly diminishing effect

Question 62

What is the antimicrobial effect of detergents?

Answer 62

the osmotic barrier is disrupted and microbes explode in hypo-osmotic solution.

Question 63

T/F. Gram positive bacteria are more susceptible than gram negative to detergents.

Answer 63

true.

Question 64

T/F. Alone quaternary or cationic ammonium preparations are high-level surface disinfectants suitable for critical items.

Answer 64

False, Alone quaternary or cationic preparations are LOW-level surface disinfectants suitable for NONCRITICAL items.

Question 65

T/F. Quaternary ammonium preparations are NOT recommended as single-ingredient surface disinfectants.

Answer 65

True.

Question 66

How are cationic agents inactivated?

Answer 66

- by anionic agents, calcium, magnesium, and iron in hard water - by organic matter or cotton applicator

Question 67

Iodine and iodophors are ___ handwashing antiseptics and ___ surface intermediate-level disinfectant.

Answer 67

good; good

Question 68

___ of iodine (alcohol solution of iodine salts) are good antiseptics but are also irritating and ___, corrodes metal, and stains skin and clothing

Answer 68

Tincture; allergenic

Question 69

Define iodophors.

Answer 69

Iodine combined with solubilizing agents to stabilize the iodine and slowly release it.

Question 70

Iodophor carriers are ___ that increase tissue ___ and ___ cleaning effectiveness.

Answer 70

surfactants; permeability; surface

Question 71

T/F. Iodine and iodophor solutions must be made fresh daily with distilled water.

Answer 71

True.

Question 72

What has primary antimicrobial activity by oxidation as hypochlorous acid and rapidly causes unfolding and aggregation of proteins?

Answer 72

chlorine-containing compounds

Question 73

For intermediate level disinfection, OSU and NCH use ___ ___/alcohol wipes.

Answer 73

quaternary ammonium

Question 74

How long can blood remain under finger nails?

Answer 74

5 days Therefore, protect epithelial integrity, no artificial nails, short nails max 1/4 in, jewerly ?

Question 75

What are the most efficacious agents for reducing the number of bacteria on the hands of personnel?

Answer 75

alcohol-based hand rubs

Question 76

What is recommended from visibly soiled hands?

Answer 76

soap and water

Question 77

What is recommended for routine decontamination of hands for all clinical indications (except when hands are visibly soiled) and as one of the options for surgical hand hygiene?

Answer 77

alcohol based hand rubs

Question 78

Why should one not wash before or after using alcohol based hand rubs?

Answer 78

do NOT wash BEFORE because may pre-irritate skin | do NOT wash AFTER because may remove emollients

Question 79

When antiseptic hand cleansers are used repeatedly may accumulate on epithelial tissues providing a residual effect - termed ___.

Answer 79

substantivity

Question 80

What hand hygiene technique is recommended if exposure to potential spore-forming pathogens or outbreaks of Clostridium difficile?

Answer 80

hand washing with soap and water

Question 81

How long for hand hygiene with alcohol rub? soap and water?

Answer 81

alcohol - 20-30 secs | soap - 40-60 secs