Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

FHHD > Sterilisation and Disinfection > Flashcards

Sterilisation and Disinfection Flashcards

1
Q

Define Sterilisation

A

The removal or inactivation of all micro-organisms from an article including viruses, bacteria and their spores’ and fungi and their spores

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Define Disinfection

A

Removal or inactivation of some micro-organisms from an article

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Define Antiseptic

A

Substance which destroys or inhibits the growth of micro-organisms - can be applied to living tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Define Asepsis

A

State of being free from living organisms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Define cleaning

A

Soil removing process - removes high proportion of micro-organisms present, usually prior to disinfection/sterilisation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the 4 main methods of sterilisation

A
  • Heat
  • Irradiation
  • Gas
  • Filtration
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are some influencing factors that affect sterilisation by heat

A
  • Temp
  • Time
  • Number of organisms
  • Species and spore-forming ability of the micro-organisms
  • Nature of contaminated materials
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Is moist heat or dry heat better for sterilisation

A

Moist heat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the conditions required to use moist heat for sterilisation

A
  • Temp>100C
  • Raising pressure of steam in pressure vessel (Autoclave)
  • Steam must be saturated and dry must not contain water droplets
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are different methods to apply dry heat sterilisation

A
  • Incineration
  • Red Heat
  • Flaming
  • Hot Air Steriliser
  • Microwave Ovens
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

When can you use hot air sterilisers

A

For materials that can withstand high temps for prolonged times and are likely to be affected by contact with steam

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What occurs in the red heat sterilisation method

A

Points of forces held in flame

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What temps and times are the minimums for dry heat sterilisation

A

160C - 60mins
170C - 40mins
180C - 20 mins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What temps, pressures (in lb/in^2) and times are the minimums for dry heat sterilisation

A

121C - 15lb/in^2 - 15 mins
126 - 20lb/in^2 - 10 mins
134 - 30lb/in^2 - 3 mins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How is Irradiation sterilisation carried out

A
  • Ionising radiation including gamma rays, x rays and accelerated electrons
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is irradiation often used for

A

Commercial sterilisation of single use items e.g. plastic straws

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Describe an example of how Gaseous sterilisation can be carried out

A

Ethylene oxide - highly penetrative and non-corrosive - used for commercial sterilisation of single use items

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Describe filtration sterilisation

A

Useful to exclude bacteria from fluids - 0.22um. pore size filter, excludes more bacteria but most viruses can pass

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are sterilisation indicators

A

Used to determine whether sterilisation has occurred e.g. inside autoclave

20
Q

Describe how biological sterilisation indicators work

A

Usually cultures of Bacillus spp - after use the strips are cultured in media and any growth is indicative of sterilisation failure

21
Q

Name some non-biological examples of sterilisation indicators

A
  • Externally calibrated thermocouple linked to a time monitor
  • Autoclave tape and Browne’s tubes show apparatus show apparatus reached correct temp
  • TST indicator strips (temp., steam, time)
22
Q

What are the 5 main methods for disinfection

A
  1. Moist Heat
  2. Ultraviolet Radiation
  3. Gases
  4. Filtration
  5. Chemicals
23
Q

Describe the basic features of the moist heat disinfection method

A
  • First choice
  • No toxic residues
  • 70-80C for a few mins kills most
  • NB - boiling water won’t sterilise surgical instruments
24
Q

Describe the basic features of the ultraviolet radiation disinfection method

A
  • Poor penetrating power

- Mercury lamps used in treatment of air, water and surfaces

25
Q

Name a gas used for gaseous disinfection and what this method would be used for

A
  • e.g. formaldehyde gas - used for rooms and complex heat sensitive equipment
26
Q

Where is the filtration disinfection method used

A

Widely applied in the removal of micro-organisms to critical sites e.g. operating theatres

27
Q

What affects the activity of chemical disinfectants

A
  • Concentration
  • No., type and location of micro-organisms
  • Temp and pH of treatment
  • Presence of extraneous material e.g. organic substances
28
Q

What classes of disinfectants are there

A
  • Alcohols
  • Aldehydes
  • Biguanides
  • Halogens
  • Phenolics
  • Peroxygenated compounds
  • Surface-active agents
29
Q

Name some alcohol disinfectants

A
  • Isopropanol

- Ethanol

30
Q

Name some aldehyde disinfectants and when are these used

A

Glutaraldehyde

Used for equipment that cannot be sterilised or disinfected by heat - broad spectrum of activity

31
Q

Name a Biguanide disinfectant and when are these used

A

Chlorhexidine

Used for disinfection of skin and mucous membranes

32
Q

Name some types of halogen disinfectant

A

Hypochlorites and iodine containing complexes (iodophors and povidone iodine)

33
Q

What are phenolic disinfectants used for

A

General purpose environmental disinfectants

34
Q

When are peroxygenated compound disinfectants used

A

For surface disinfection - good anti-microbial properties

35
Q

What kinds of surface active agents are there

A

Anionic, cationic, non ionic, Amphoteric detergents

36
Q

Are gram positive or negative bacteria generally more sensitive to disinfectants

A

Gram positive are more sensitive

37
Q

What spore producing microbes are highly resistant to disinfectants

A

Bacterial spores - highly resistant

38
Q

What type of viruses are quite sensitive to disinfectants

A

Enveloped or lipophilic viruses (HIV)

39
Q

What type of viruses are not very susceptible to disinfectants

A

Hydrophilic (Polioviruses and other enteroviruses)

40
Q

When should and instrument be sterilised

A

Any instrument that comes routinely into contact with blood, saliva or tissue that are surgically breached should be sterilised, any other should be disinfected

41
Q

What in the GD practice is disinfection generally used for

A
  • Decontamination of surfaces
  • Treatment of spillages
  • Decontamination of areas known to be grossly contaminated
  • Decontamination of non-surgical instruments
  • Decontamination prior to sterilisaiton
  • Decontamination of dental unit water supplies
42
Q

What are the 3 main sources of infection in the GD practice

A
  • Patients suffering from the infectious disease
  • Patient in the prodromal stage of certain infections
  • Individuals who are carriers of pathogenic micro-orgnaisms
43
Q

What are the 3 main ways of infection transmission in the GD practice

A
  • Direct contact of tissues with skin or body fluids
  • By droplets containing infectious agents
  • Via contaminated instruments that haven’t been rendered safe for re-use
44
Q

What are the advantages and disadvantages of using the Autoclave for sterilisation

A

Advantage: Running costs low
Disadvantages: Apparatus is expensive and it rusts the dental instruments

45
Q

How do Chemiclaves work

A

Various micro-biocidal substances at high temps usually in vapour form

46
Q

What are some advantages and disadvantages for using the chemiclave for sterilisation

A

Advantages: Does not rust dental instruments; cycles cannot be interrupted

Disadvantages: Long cycle time; vapours may be harmful; Machine needs careful maintenance; Chemicals involved are expensive

47
Q

What are the advantages and disadvantages of hot air ovens

A

Advantages: Very cheap to run

Disadvantages: long cycle; not reliable even when fitted with circulatory fans; Damages instruments; sterilisation cycles can be interrupted

FHHD (21 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions