MICB W7 Instrument Reprocessing and Waste Management

Review: What are the 3 types of Sterilization techniques used in Densitry?

1. Heat → most common, uses steam, dry heat and unsaturated chemical vapour

2. Gas → not often used

3. Liquid Chemical → not often used; only used on items damaged by heat sterilization (ex. glutaraldehyde)

What are the 3 categories of patient care items as per the CDC? Define each.

1. Critical → items need to be cleaned and sterilized by heat

   • Any item that will penetrate soft tissue, bone, or enters the blood stream

   • ex. surgical instruments, scalers, blades, dental burs

2. Semi-critical → items to be cleaned and sterilized by heat or high level disinfectant if heat sensitive

   • Any item that will contact mucous membrane but WONT penetrate soft tissue, contact bone or enter/contact blood stream

   • ex. dental mirror, reusable dental impression trays, dental hand piece

3. Non-critical → treated with low-level disinfectant if no blood is visible; with blood then use intermediate disinfectant

   • Contacts only INTACT skin

   • ex. BP cuff, stethoscope, lead apron

** classification is based on the potential risk of infection during use of the items

Define Universal sterilization

All reusable instruments and hand pieces are sterilized between uses on patients

• provides the highest level of patient protection

Define Sterility assurance

The correct performance of the proper instrument processing steps and monitoring of the sterilization steps with biological, mechanical and chemical indicators

• Sterility assurance requires showing that the process used kills bacterial endospores

If items used in a clients mouth CANNOT be sterilized (b/c cannot withstand sterilization) then…?

the item should NOT be used or must be discarded after ONE use on ONE patient.

Define pre-cleaning. What is a safer alternative to pre-cleaning?

Precleaning is the initial removal of debris (blood, saliva, food, biofilm) from instruments or surfaces before disinfection or sterilization.

• Ensures the disinfectant/sterilant can work effectively

• Often done by rinsing, scrubbing, or ultrasonic cleaning

• high risk of sharp injuries

Safer alternative → use gauze pad on a surface, hold instrument with one hand and wipe the tip on the gauge without using the other hand.

Define Holding/Presoaking. When is it used?

Holding/presoaking helps the cleaning process by preventing debris from drying out. Instruments in placed in a HOLDING solution.

• solution can be water, or an enzyme solution

• Pre-soaked instruments and holding solution are CONTAMINATED still.

• Discard solution once a day and when visibly soiled

• Loose instruments placed in a perforated cleaning basket then into the solution to reduce direct handling

What is Bioburdem?

Bioburden is the presence of MO on a surface or item, prior to sterilization (blood, saliva, tissue fluids, dental material etc.)

What are the 2 basic types of dental instrument cleaning systems that are considered safe and effective by the FDA?

1. Ultrasonic cleaners

2. Instrument washers/washer-disinfectors → look kind of like a dishwasher, but it is not

**cleaned instruments still need to be visually inspected for cleanliness and damage

What is the Aluminum foil test used for?

Used to check whether the ultrasonic cleaners are working as expected.

• Foil should not touch the bottom of the unit

• placed in the unit for 20 seconds

• pebbling should be uniform on the foil

Carbon steel will rust during Steam sterilization. How should we sterilize instruments made of this material?

• Use dry heat or unsaturated chemical vapour

• replace with stainless steel type instruments

• dip instrument in rust inhibitor (sodium nitrite)

Flash sterilization/immediate-use steam sterilization is NOT CDC recommended for ..?

unpackaged instruments using short exposure times for routine use is not recommended.

The heat, not the pressure, inside a steam sterilizer is what kills the microorganisms. True or False?

True 

• In a steam sterilizer, it’s the moist heat (at high temperature) that kills microorganisms, while pressure only allows the steam to reach those high temperatures.

Drying packages before removing them from the sterilizer is important to prevent wicking. True or False

What are the 4 steps of the steam sterilizer?

1. Heat up Cycle → generate heat, remove air

2. Sterilizing Cycle → temp is held for set time

3. Depressurization Cycle → steam released slowly, decrease temp and pressure; insides are wet)

4. Drying Cycle

What are the set parameters of a standard cycle and immediate-use cycle of a Steam autoclave?

Standard: 15-30 minutes at 121C (250F) OR 3.5-10 minutes at 132C (270F)

Immediate-use: 3-10 minutes at 134C (273F)

What are the 3 main types of Steam sterilizers?

1. Gravity displacement (N-class)

2. Vacuum pump (B-class)

3. Positive steam flush/pressure pulse (S-class)

What are 2 advantages of using Unsaturated Chemical Vapour Sterilization?

Chemiclave / Thermo Scientific Harvey Sterilizer

1. reduces or eliminates corrosion of carbon steel instruments (need to be dry)

2. 20 min cycles at 132.2C (270F)

*uses hot chemicals as the steam instead of just water.

What are the 2 types of Dry heat sterilization?

1. Static air type of dry heat sterilizer (oven type)

   • heating coils to 160C (320F) for 1-2 hours

   • cannot open until cycle is complete

   • use of proper packaging materials

2. Forced air (rapid heat transfer) type

   • heated air circles chamber at high velocity (6-12 mins)

     • 12 mins at 190.6C (375F) wrapped

     • 6 minutes at 190C unwrapped

What are the 3 common types of sterilization monitoring used in dental offices?

1. Biological monitoring (spore testing) - uses live spores (Geobacilus stearothermophilus and Bacillus atrophaeus)

2. Chemical monitoring - uses heat sensitive chemicals

3. Mechanical monitoring - observation of gauges and displays on the sterilizer (temp, pressure, exposure time)

According to the textbook (Miller 2023) when should we spore test? (6)

1. Once per week

2. Whenever a new type of packaging material or tray is used

3. after t raining of new sterilization personnel

4. During initial use of sterilizer

5. First run after sterilizer repair

6. After any change in sterilizing procedure

As per Ontario Public Health, when should we spore test?

Daily

How does chemical monitoring work as a sterilization monitor? Where are they located?

Use of indicators that change colour or physical form when exposed to high temps to a certain combination of time/temp and presence of steam.

• can be external or internal

• ex. autoclave tape

What are the 6 classes of chemical indicators?

Class:

1. External → shows the package has been exposed to the sterilization process

2. Specific Test procedure (ex. Bowie-Dick test) does not test sterilization but air removal in a vacuum steam sterilizer

3. Internal → reacts to a single critical variable (ex. temp)

4. Multivariable Internal → reacts to two or more variables (temp, time, pressure)

5. Integrating internal → react to all critical variables

6. Emulating internal → reacts to all critical variables

What are mechanical monitors? What is a disadvantage of this type of monitoring?

Sterilizer gauges and displays that indicate conditions in sterilizer chamber rather than the conditions within the packets/pouches/cassettes being processed.

• Problem: may not detect problems resulting from overloading, improper packaging, use of closed containers

*should not use mechanical monitoring alone

What are 6 causes for Sterilization Failure

Improper:

1. instrument cleaning

2. Packaging

3. Loading of sterilizer

4. Timing

5. Temperature

   1. Method of sterilization

Chemical monitors give _______ of instrument safety.

immediate indication

What is the only thing capable of showing and guaranteeing instrument safety?

Biological indicators

The greatest safety in a dental office is achieved by:

1. cleaning

2. sterilizing

3. instrument sharpening

4. instrument re-sterilizing

What is the safest option when maintaining instrument sharpness?

Providing multiple scalers in each instrument kit rather than sharpening contaminated scalers

**if sharpening chairside is required, a clean sterilized sharpening stone should be provided.

When would use of liquid sterilant/high-level disinfectants or other liquid germicides to disinfect be not recommended?

when disinfecting heat-tolerant instruments → they should be sterilized by the autoclave (heat sterilizer)

What are the 2 main types of waste in dental offices?

1. Regulated medical waste

2. Nonregulated medical waste

Define Regulated medical waste according to OSHA (occupational safety and health admin) (5)

1. Liquid or semiliquids → blood or saliva

2. Contaminated items that would release blood or OPIM (Other Potentially Infectious Materials) in a liquid or semiliquid state if compressed → ex. gauze or cotton rolls saturated with blood or saliva

3. Items that are caked with dried blood or OPIM → gauze, cotton rolls, caked with dried blood or saliva

4. Contaminated sharps → needles, scalpels, ortho wire, broken instrument, burs

5. Pathological or microbial waste containing blood or OPIM → biopsy specimen, excised tissue, extracted teeth

What is the difference between medical waste and infectious waste?

Medical waste → any solid waste generated during patient diagnosis, treatment, or immunization in healthcare facilities

Infectious waste → subset of medical waste that has shown a capability of transmitting infectious disease; AKA REGULATED MEDICAL WASTE

What is pathogenic waste in dentistry? How is it different to infectious waste?

Pathogenic waste in dentistry would be teeth (or other tissues).

• They are disposed in the sharps container

• CDHO says teeth can be disposed of as general office waste if they do not contain amalgam restoration.

Pathogenic waste = known to contain dangerous pathogens

Infectious waste = suspected to contain pathogens

Blood-soaked materials MUST be placed in a _____ liner bag labelled with ___?

YELLOW liner bag labelled with the UNIVERSAL biohazard symbol

Sharps must be disposed in a YELLOW ________, ________ container specifically designed for their management. Container is labelled with the universal biohazard symbol.

puncture-resistant AND leak-proof container

What is considered a sharp?

Sharps are any item that can penetrate intact skin or other tissues.

• contaminated sharps are considered infectious waste

How should we dispose of Amalgam waste?

• Amalgam is to be recycled as much as possible

• Separate amalgam into a labelled container

• Teeth with amalgam restorations can be recycled. Do not discard.

• Do not rinse amalgam over a drain or sink.

How should we dispose of Lead?

• Lead is considered a hazardous waste

• It is recycled and NOT thrown into the trash or flushed down sinks

Who regulates the management of biomedical waste in Ontario?

Ministry of the Environment and CLimate change through the Environmental Protection Act (EPA)

What is Cytotoxic waste?

Waste consisting of cytotoxic drugs, a medicinal chemical or waste containing a waste listed.

• waste containing tubing, tissues, needles, gloves, vials, prep material, ampoules, cleaning materials, PPE

Universal Biohazard Symbol vs Anatomical Symbom