M1 Infection Prevention - Module 5

Infection Control

What is the Spaulding Classification System for sterilization and disinfection?

• Developed by Earle H. Spaulding as a practical approach for sterilization and disinfection.

• Classifies patient-care items based on the risk of transmitting healthcare-associated infections (HAIs).

• Three categories of patient-care items:

  • Critical: Highest risk → require sterilization

  • Semi-critical: Intermediate risk → require high-level disinfection

  • Non-critical: Lowest risk → require cleaning and low/intermediate-level disinfection

• Remains the foundation for modern sterilization and disinfection practices.

What are critical patient-care items and how are they processed?

• Highest risk category because they penetrate:

  • Soft tissue

  • Hard tissue

  • Vascular system

• Contamination with pathogens can cause serious infections.

• Examples in oral healthcare:

  • Surgical instruments

  • Periodontal scalers

  • Scalpel blades

  • Burs

  • Explorers

• Heat-tolerant critical items: Must be sterilized using an FDA-cleared heat sterilizer.

• Heat-sensitive critical items: Require low-temperature sterilization or an FDA-registered chemical sterilant.

What are semi-critical patient-care items and how are they processed?

• Contact mucous membranes or nonintact skin but do not penetrate tissues.

• Have a lower infection risk than critical items.

• Examples in oral healthcare:

  • Mouth mirrors

  • Amalgam condensers

  • Dental impression trays

  • Cheek retractors

  • Dental handpieces

  • Air-water syringes

  • Orthodontic pliers

• Heat-tolerant semi-critical items: Must be heat sterilized (including all dental handpieces).

• Heat-sensitive semi-critical items: Require at least high-level disinfection with an FDA-registered chemical sterilant.

What are non-critical patient-care items and how are they processed?

• Contact intact skin only (do not contact mucous membranes or sterile tissues).

• Lowest risk for infection transmission because intact skin protects against microorganisms.

• Examples in oral healthcare:

  • Radiographic equipment

  • Blood pressure cuffs

  • Facebows

  • Pulse oximeters

  • Examination and curing lights

  • Computers

• Preferred method: Use disposable barriers to protect clinical contact surfaces.

• If visibly soiled:

  • Clean and disinfect with an EPA-registered hospital-level disinfectant with tuberculocidal claim.

  • Follow manufacturer instructions to meet OSHA requirements.

Front: How are heat-tolerant critical and semi-critical items sterilized?

• Must be sterilized using:

  • Steam sterilization

  • Unsaturated chemical vapor

  • Dry heat

• Applies to items that can withstand high temperatures.

How are heat-sensitive critical and semi-critical items processed?

• Heat-sensitive critical items:

  • Sterilize using:

    • Ethylene oxide

    • Hydrogen peroxide gas plasma

    • FDA-registered liquid chemical sterilants

• Heat-sensitive semi-critical items:

  • Require at least high-level disinfection with a chemical sterilant.

How are non-critical items (clinical contact surfaces) disinfected?

• Contact intact skin only and have the lowest infection risk.

• When visibly soiled:

  • Clean and disinfect with an EPA-registered hospital-level intermediate disinfectant.

• Follow manufacturer instructions for proper use and OSHA compliance.

What is steam sterilization (autoclaving) and why is it used?

• Most dependable and economical sterilization method.

• Most commonly used for wrapped and unwrapped critical and semi-critical items that are not heat/moisture sensitive.

• Requires:

  • Direct steam contact

  • Specific temperature and pressure

  • Correct exposure time

• Two main types:

  • Gravity displacement

  • High-speed prevacuum

How does a gravity displacement sterilizer work?

• Commonly used in oral healthcare tabletop sterilizers.

• Steam enters the chamber and forces air out through a vent.

• Sterilization failure can occur due to:

  • Incorrect packaging

  • Overloading the chamber

  • Cool air pockets preventing steam contact

How does a high-speed prevacuum sterilizer work?

• Uses a pump to create a vacuum before steam enters the chamber.

• Removes air to improve steam penetration throughout the load.

• Provides faster and more reliable sterilization compared with gravity displacement.

• Requires daily testing for proper air removal.

• Residual air can cause sterilization failure.

What is unsaturated chemical-vapor sterilization?

• Uses a heated chemical solution (primarily alcohol with 0.23% formaldehyde) in a closed, pressurized chamber.

• Causes less corrosion of carbon steel instruments (e.g., dental burs) compared with steam sterilization because less water is used.

• Instruments must be completely dry before sterilization.

• Chemical solution disposal must follow federal, state, and local hazardous waste requirements.

What is dry-heat sterilization and when is it used?

• Used for items that may be damaged by moist heat (steam).

• Examples:

  • Dental burs

  • Certain orthodontic instruments

• Advantages:

  • Low operating cost

  • Noncorrosive

• Disadvantages:

  • Requires high temperatures

  • Longer sterilization time

  • Not suitable for many instruments/devices

What are the two types of dry-heat sterilizers?

• Static-air sterilizer (oven type):

  • Uses heating coils and natural convection to circulate hot air.

• Forced-air sterilizer (rapid heat-transfer type):

  • Circulates heated air at high velocity.

  • Transfers heat faster and reduces sterilization time.

What is low-temperature sterilization with ethylene oxide (ETO)?

• Used to sterilize heat- and moisture-sensitive patient-care items.

• Commonly used in larger healthcare facilities.

• Advantages:

  • Effective for delicate instruments

  • Causes fewer damaging effects

• Disadvantages:

  • Long sterilization time (10–48 hours)

  • Requires strict safety precautions due to hazards to patients and OHCP

  • Not practical for most private dental practices.

How are chemical sterilants used for heat-sensitive critical and semi-critical items?

• Heat-sensitive critical items:

  • Must be immersed in FDA-registered chemical sterilants for 3–12 hours to achieve sterilization.

• Heat-sensitive semi-critical items:

  • Require at least high-level disinfection.

  • Immersed in FDA-registered chemical sterilants for ≥12 minutes.

• Always follow manufacturer label instructions.

How are non-critical patient-care items disinfected?

• Non-critical items = clinical contact surfaces.

• When visibly soiled:

  • Clean and disinfect with an EPA-registered intermediate-level disinfectant.

• Use:

  • List B: Hospital disinfectant with tuberculocidal claim

  • List E: Hospital disinfectant with tuberculocidal + HIV/HBV claims

• Most products require about 10-minute contact time.

• Follow label instructions for proper use.

What is required for safe processing of contaminated reusable patient-care items?

• Requires:

  • Adequate space

  • Specialized equipment

  • Trained personnel

• Proper steps must be followed:

  • Transport

  • Cleaning

  • Packaging

  • Sterilization/disinfection

  • Storage

• OHCP should receive ongoing training and processes should be regularly monitored.

What are the four stations in a Central Processing Area (CPA)?

1. Receiving and cleaning contaminated instruments

2. Preparation and packaging of instruments

3. Sterilization or disinfection process

4. Storage of sterilized items (packs, pouches, containers)

• Stations should be physically or spatially separated to control traffic flow and prevent contamination.

How should contaminated reusable patient-care items be transported?

• Transport items from the point of use to the Central Processing Area (CPA).

• Use appropriate PPE to prevent exposure to:

  • Blood

  • OPIM

  • Contaminated materials

• Transport in sealed, leak-proof containers with a biohazard symbol.

• Prevents exposure through:

  • Percutaneous injury

  • Nonintact skin contact

  • Mucous membrane contact (eyes, nose, mouth)

Spaulding Classification System

How are patient-care items classified for sterilization/disinfection?

• Classifies items based on risk of infection transmission

• Three categories:

  • Critical: penetrate tissue or vascular system → highest risk

  • Semi-critical: contact mucous membranes or nonintact skin

  • Non-critical: contact intact skin only → lowest risk

Critical Patient-Care Items

• Highest infection risk

• Penetrate:

  • Soft tissue

  • Hard tissue

  • Vascular system

• Examples:

  • Surgical instruments

  • Periodontal scalers

  • Scalpel blades

  • Burs

  • Explorers

• Processing:

  • Heat-tolerant → sterilize with FDA-cleared heat sterilizer

  • Heat-sensitive → low-temperature sterilization or FDA-registered chemical sterilant

Semi-Critical Patient-Care Items

What are semi-critical items and how are they processed?

• Contact:

  • Mucous membranes

  • Nonintact skin

• Do not penetrate tissues

• Examples:

  • Mouth mirrors

  • Impression trays

  • Dental handpieces

  • Air-water syringes

  • Orthodontic pliers

• Processing:

  • Heat-tolerant → heat sterilization required

  • Heat-sensitive → high-level disinfection minimum

Non-Critical Patient-Care Items

What are non-critical items and how are they processed?

• Contact intact skin only

• Lowest risk of infection transmission

• Examples:

  • X-ray equipment

  • Blood pressure cuffs

  • Pulse oximeters

  • Computers

  • Exam lights

• Preferred method:

  • Use disposable barriers

• If visibly contaminated:

  • Clean + disinfect with EPA-registered hospital-level disinfectant

Methods of Sterilization & Disinfection

How are different items sterilized/disinfected?

• Heat-tolerant critical & semi-critical

  • Steam

  • Unsaturated chemical vapor

  • Dry heat

• Heat-sensitive critical

  • Ethylene oxide (ETO)

  • Hydrogen peroxide gas plasma

  • Chemical sterilants

• Heat-sensitive semi-critical

  • High-level disinfection with chemical sterilant

• Non-critical surfaces

  • EPA-registered intermediate-level disinfectant

What are the packaging requirements for instruments at the second station of the CPA?

• Instruments may be placed in:

  • Self-sealed or heat-sealed plastic/paper pouches

  • Rigid or perforated trays/cassettes that are wrapped

• Complex instruments must be disassembled according to the manufacturer’s instructions.

• Hinged instruments must be placed in an open, unlocked position.

• Packaging material must allow penetration of the sterilization agent to reach the items being sterilized.

What is the purpose and setup of the third station of the CPA?

• The third station is where sterilizers and related supplies are located.

• It must have adequate space for loading and unloading sterilizers.

• The area may also contain:

  • Incubators for spore testing

  • Storage for sterile instrument units

  • Storage for disposable (single-use) items

• Placement and ventilation requirements are determined by manufacturer specifications and building codes.

What is flash sterilization and how are unwrapped instruments sterilized?

• Flash sterilization is a method used to sterilize unwrapped patient-care items for immediate use.

• The required sterilization time depends on:

  • The type of sterilizer

  • The type of instrument being sterilized (porous or nonporous)

• Tabletop sterilizers use a preprogrammed unwrapped cycle with specific:

  • Time settings

  • Temperature settings

• The cycle may include a drying phase to produce a dry instrument and dissipate much of the heat before use.

• Unwrapped sterilization method must meet four criteria: (1) the instruments must be thoroughly cleaned and dried prior to the cycle; (2) mechanical indicators must be checked and, at a minimum, a chemical indicator must be placed with the items to be sterilized; (3) care should be taken to avoid thermal injury to OHCP or patients; and (4) items must be transported aseptically to the point of use. Unwrapped or flash sterilization of implantable items is not recommended.

  
  

What are the risks associated with chemical sterilants?

Chemical sterilants can cause:

• Skin irritation

• Eye irritation

• Respiratory tract irritation

• Reactive airway disease

What precautions reduce the toxicity of chemical sterilants?

Safety precautions include:

• Using closed containers to limit vapor release

• Wearing chemically resistant gloves and aprons

• Using goggles and face shields

• Providing special ventilation with 10 air exchanges per hour

When should heat-sensitive critical and semi-critical items be used?

The use of heat-sensitive critical and semi-critical items is generally discouraged when:

• Heat-tolerant alternatives are available

• Disposable alternatives are available

What steps must be followed after sterilization or high-level disinfection with germicides?

Processed items must be:

1. Rinsed with sterile water to remove toxic or irritating residues

2. Handled with sterile gloves

3. Dried with sterile towels

4. Delivered to the point of use using aseptic technique

5. Used immediately (items cannot be stored)

Can the effectiveness of germicide-based sterilization or high-level disinfection be verified?

No. The efficacy of sterilization or high-level disinfection processes using germicides cannot be verified.

What must be followed when using FDA- or EPA-registered germicide products?

Federal law requires following label instructions, including:

• Use dilution

• Shelf life

• Storage requirements

• Material compatibility

• Safe use

• Disposal procedures

What happens if a germicide product is used outside its FDA/EPA label instructions?

The user assumes liability for injuries caused by off-label use and may face enforcement action under FIFRA (Federal Insecticide, Fungicide, and Rodenticide Act).

How should sterilized instruments be stored?

• Ensure packages are dry and cool

• Check chemical indicator color change

• Store in a clean, dry, closed cabinet

• Use event-related storage (sterile until contamination occurs)

When are sterilized packages considered contaminated?

When an event compromises the package, such as:

• Torn packaging

• Wet packaging

• Open packaging

What should be done if sterile packaging is damaged?

Re-clean, re-package, and re-sterilize the instruments.

Why label sterilized packages with the sterilization date and sterilizer used?

To help identify and retrieve instruments if a sterilization failure occurs.

What are the three indicators used for sterilization quality assurance?

• Physical indicators

• Chemical indicators

• Biological indicators
  Used together to evaluate sterilization conditions and effectiveness

What records must be kept for sterilization quality assurance?

• Sterilization monitoring records documenting indicator results

• Maintenance records for each sterilizer

What are physical indicators used to monitor during sterilization?

Physical indicators monitor and record:

• Time

• Temperature

• Pressure
  for each sterilization cycle.

Do correct physical indicator readings guarantee sterilization?

No. Correct readings do not guarantee sterilization, but incorrect readings may indicate a problem and that the load may not be sterile.

Do chemical indicators prove sterilization was achieved?

No. They do not prove sterilization, but they can provide early warning of problems in the sterilization process.

How often should biological indicators be used in oral healthcare facilities?

• Test all sterilizers at least weekly

• Test every load containing an implant

• Quarantine implants until BI results are know

What do biological indicators (BIs) test?

BIs (spore tests) directly test the killing of highly resistant bacterial spores to verify sterilization effectiveness.

What do BI test results mean?

• No growth (clear): Negative test — sterilization successful

• Growth (cloudy): Positive test — sterilization failure

What are the three forms of biological indicators?

Back:

• Spore strips

• Self-contained spore vials

• Spore ampules

What is the purpose of the Sterilization Monitoring Record (SMR)?

The SMR:

• Documents ongoing sterilization monitoring

• Confirms cycle parameters using appropriate indicators

• Provides evidence of quality assurance

How does the SMR help with recalls?

The SMR helps determine:

• If a recall is needed

• The extent of the recall using sterilization date and sterilizer number

How often should sterilization equipment be maintained?

Sterilization equipment requires:

• Daily maintenance

• Periodic maintenance
  according to manufacturer instructions.

What information should be included in a sterilizer maintenance record?

• Model and serial number

• Date of service

• Reason for service (periodic, preventive, or sterilization failure)

• Work performed

• Name/initials of person performing service

Why is a sterilizer maintenance record required?

It is the fifth component of quality assurance and ensures sterilizers operate accurately and reliably.

What should be done after a positive spore (BI) test?

• Remove sterilizer from service

• Review physical and chemical monitoring records since the last negative BI

• Review cleaning, packaging, loading, and testing procedures

• Repeat the BI test after correcting possible errors

What happens if the repeat BI test is positive or negative?

• Negative BI + proper monitoring: Return sterilizer tco service

• Positive BI: Keep sterilizer out of service until repaired and tested with BI in 3 empty-chamber cycles

• Conservative approach: Re-clean, re-wrap, and re-sterilize items from suspect loads since the last negative BI