10. Sterilisation And Disinfection

Question 1

LOs

Answer 1

Question 2

Disinfection definition

Answer 2

“The destruction or removal of all or nearly all pathogens, but not all microorganisms”

This process may not be absolute and may result in only a reduction in the number of potentially harmful microorganisms. E.g. spores

Disinfection invariably relates to the killing or removal of virulent microorganisms; but not always their total elimination

Question 3

Sterilisation definition

Answer 3

“The destruction or removal of all microorganisms”

•Bacteria, viruses, fungi, algae, protozoa and their spores

This is an ‘absolute’ and at the end of a sterilization process, no viable microorganisms are present

Question 4

Decontamination definition

Answer 4

“Decontamination is a combination of processes carried out to render a contaminated reusable medical device safe to use again”

•Not a sterility absolute; it depends upon the nature of the equipment and the use characteristics for the types of procedure for which they are required.

Question 5

Classification of Procedural Risk Related to Decontamination Requirements

1. Category of IC risk
2. Procedure type (use characteristics)
3. Level of decontamination required

Answer 5

• each instrument that you use can be given a risk category

Question 6

why do dental instrument and equipment need to be decontaminated

Answer 6

• basic principle is that if something can be sterilised, it will be
• a lot of instruments used cannot be single use and cannot be sterilised easily EG a lite cure unit

Question 7

what is the single-use symbol

Answer 7

Question 8

Cross-Contamination and/or Cross-Infection definition?

Answer 8

• cross- contamination = spreading microorganisms from one place to another
• cross infection = giving someone an infection because we’ve cross contaminated them

“The transmission of a microorganism (infection) from one place/person to another in the same healthcare environment ” = a big issue for dentists

…To occur it requires a number of factors (6) to be in place

Question 9

are the terms cross infection and cross contamination still used?

Answer 9

• the term infection control is used more now currently as we are trying to stop infection and control the contamination that causes it

Question 10

why is infection control important to us as dentist?

Answer 10

• what we do in our environment makes us legally liable
• as soon as patient walks into surgery, the dentists have a duty of care to prevent them from coming into contact with potentially infective microorganisms

Question 11

What needs to occur for cross infection to occurs

Answer 11

• requires a number of factors (6) to be in place for it to occur
• if all 6 are in place you can get transmission and an infection caused by cross contamination
• if you break the chain you can prevent this happening

Question 12

Types of infection agents transmissible during healthcare procedures

Answer 12

Question 13

What are reservoirs? Where are they?

Answer 13

• commonly in complex instruments (if not sterilised correctly will harbour bacteria)
• water supplies if not regularly checked (can grow significant levels of microorganisms as working in environment which are already highly bacteria colonated areas anyway - EG plaque amount = 10^11 cfu/ml)

Question 14

CFU meaning?

Answer 14

Colony forming unit

Question 15

instruments we use can be split into 2 different categories

Answer 15

Question 16

How do they exit from equipment use into patient?

Answer 16

-Hands
↳ most common area of cross contamination
↳ clean hands do not transmit but if not cleaned properly then bad

• introduced through contaminated solid instrument
• can spray into patients mouth through aerosols via drills

Question 17

How is it transmitted?
(Mechanisms of cross contamination)

Answer 17

1. Direct contact: infectious agent transmission from the same or different person
2. Indirect contact: via instruments and equipment
3. Inhaled/airborne: DUWL’s, sneezing, coughing etc
4. Ingested: food and water hygiene
5. Vector: clothing, towels, insects, animal contact etc

Question 18

portal of entry of infection?

Answer 18

once it’s in, it can get in through:

• gingival margin
• cavity that the patient might have (such as surgical wound)
• area of infection patient is exhibiting
• area of unintact mucosa or skin
• area of non-healing bone
• several ways if we’re not directly injecting it that the patient is still susceptible to infection

Answer 19

• patient needs to be susceptible to it
• many patients have conditions that put them at higher risk of getting an infection
• have a weakened immune system
• health care associated (acquired) infections in diagram

Question 20

How are medical devices decontaminated?

Answer 20

Question 21

Decontamination cycle stages

Answer 21

Question 22

Can instruments be packaged if they’re going to be put through a non vacuum autoclave during the decontamination cycle? why?

Answer 22

• no
• packaging would only be used if the instruments are going to go through a vacuum autoclave
• cannot package if putting in a non-vacuum autoclave
  BECAUSE
• the non-vacuum wouldn’t penetrate the package that you put the instrument into
• special packaging allows steam to penetrate through the package
• hence only put instruments in packaging before sterilisation if they’re going to be sterilised in a vacuum autoclave

Question 23

Decontamination cycle stages equipment?

Answer 23

TRANSPORT
- trolleys on clincis where you can put used instruments that have been bagged up into non-sterile bags so they can be taken into central sterilising department (CSD)
CLEANING
- may need to be manually cleaned or automatically cleaned
DISINFECTION
- ultrasonic disinfectant (has chemicals in it that will denature proteinaceous material - EG bacteria, viruses, etc)
- or could just be cleaner, EG handpiece oiler and cleaner
- automated washer disinfector
INSPECTION
- labs use magnification
PACKAGING
- allows steam to penetrate but water cannot come back in once dried
STERILIZATION
- 3 types of autoclave (non-vacuum (N type), vacuum (B type), specialised (S type))
TRANSPORTED AND STORED
-back to suitable storage areas

Question 24

Modifying factors for effective disinfection and sterilisation

Answer 24

Some pieces or equipment cannot be sterilised so we run the risk of transmitting potentially infecting organisms to the next patient
Hence we:
↳ barrier cover them (reduced bioload to equipment)
↳manually disinfect chemically in between patients

Question 25

Disinfection types

Answer 25

Question 26

Automated water disinfectors stages

Answer 26

Question 27

Sterilisation types

Answer 27

Question 28

Autoclave sterilisation parameters

Answer 28

Question 29

Autoclave steriliser types

Question 30

Autoclave sterilisation cycles

Answer 30

Question 31

In summary know

Answer 31