13. Disinfection & Sterilisation Flashcards
What agent should be used for high level disinfection with heat sensitive surgical instruments?
Aldehyde
Why is N95 mask called N95?
It prevents 96% of particles of very small (0.3 micron) particles
List out all the disinfection chemicals we use.
- Glutaraldehyde (heat sensitive items)
- Hypochlorites/Chlorine compounds (mainly kills virus)
- Iodine-based/Lodophors (wide range: bacteria, virus, fungi, only sporicidal antiseptic)
- Phenolics (domestic disinfection, but poor virucidal & sporicidal)
- 70% Alcohol (skin disinfection)
- Chlorhexidine (for plaque control)
NOTE: PROF SAY DUNNIT MEMORISE THE CHARACTERISTICS OF ALL THE DISINFECTING AGENTS!! SO IGNORE THE NEXT FEW CARDS
What is Gluraldehyde used for + pros and cons?
Pros:
1. For heat-sensitive items + non-damaging to metals, plastic, rubber
2. Clean semi-critical objects & endoscope
3. Sporicidal but slow activity against mycobacteria (TB), but still works ig
Cons:
1. Irritant to skin, eyes, respiratory tract
What is Hypochlorites/Chlorine compounds used for + pros and cons?
Pros:
1. Mainly kills virus, some bacteria and spores
2. For environmental cleaning: blood spills on floor & instruments
- extra strong (1%, 10000ppm): blood spillage
- strong (2.5%, 2500ppm): lap pipette jars, antiseptic for dirty wounds
- strong (1%, 1000PPM): general environmental use
Cons:
1. Caustic(burn/corrode) to tissues & corrodes metals
(Bleach)
What is Iodine-based/Lodophors used for + pros and cons?
Pros:
1. Kills wide range of bacteria, virus, fungi (fast anti-viral action on clean surface)
2. For surface disinfection & antiseptic
3. Iodine: only antiseptic that is sporicidal
4. Cheap & effective
Cons:
1. Corrodes metals, cause allergy, inactivated by organic matter
What is Phenolics used for + pros and cons?
Pros:
1. For domestic disinfection: washing, cleaning floors
Cons:
2. Poor virucidal & sporicidal, taint food, corrosive
What is 70% Alcohol used for + pros and cons?
Pros:
1. For skin disinfection (antiseptic) => hand rub
2. For surface disinfection, rapid action
Cons:
1. Does not kill spores (does not penetrate organic matter)
2. Evaporates quickly => no residual effect
What is Chlorhexidine used for + pros and cons?
Pros:
1. Plaque control: adsorbs to enamel & salivary pellicle => retain antimicrobial activity
2. Antiseptic: sustained/retentive action on skin => hand sterilisation for surgery
Cons:
1. Limited against virus, does not kill spores & mycobacteria
2. Unpleasant taste, may discolour tooth/gingiva
What happens in the instrument processing area?/Steps for infection control?
- Cleaning & decontamination
- Disinfection: decreases no. of viable microorganisms, except spores & prions
- Sterilisation: completely remove all viable microorganisms, including spores (+ preparation & packaging b4 sterilisation)
- Assessing sterilisation + storage!!
What are the categories of infection control?
- Critical: penetration of tissue by intent/accident => sterilisation (e.g. scalers & blades)
- Semi-critical: contact intact mucous membrane => high lvl disinfection (e.g. mouth mirror, impression tray, handpiece)
- Non-critical: contact intact skin => low-level disinfection/cleaning (e.g. facebow)
IMPT!!!
List the microorganisms in decreasing hardiness.
Spores>TB>normal bacteria>virus
Methods of sterilisation are..
- Heat sterilisation (moist
- Ionising radiation
- Chemical
- Gas plasma
- Glutaraldehyde
Definition of Disinfection:
A process used to reduce the number of viable micro-organisms on a surface or in a load, but which may not necessarily inactivate some microbial agents (e.g. spores & prions)
Spores are a prob in SG, prions not so much
Definition of Sterilisation:
A process which renders a product free from viable micro-organisms. It achieves the complete killing or removal of all types of micro-organisms, including spores. (of tetanus and gas-gangrene bacilli which are resistant to most disinfectants, and spores which are more resistant to heat than non-sporing organisms.)
