Lecture 4 Infection Control Surfaces.pdf

Infection control in dentistry is an ever-growing perturbation. Dental patients are high-risk patients relative to their potential to transmit as well as acquire an infectious disease. An equal concern has been exhibited for cross-contamination and disease transmission from patient to patient. When addressing these problems, there are two identifiable considerations: (1) how the dentist and his staff can be safeguarded from disease acquisition and disease transmission to patients and (2) what steps should be taken to help minimize cross-contamination with instrumentation. The constant dangers of cross-contamination in dental practice among patients, dentists, and ancillary staff have been pointed out by Murray and Slack; they reported the possibility of absorbent cotton pledgets, air syringes, glass slabs, and hand towels acting as sources of contamination. The Centers for Disease Control and Prevention (CDC), in its infection control guidelines, indicated that dental impressions are potential sources of cross-contamination and should be handled in a manner that prevents exposure to practitioners, patients, and the environment. Based on the corroboration of data and regulation confined to the province, appreciative standards of Dental Infection Control and Occupational Safety must be followed by the dental team for patient and dental healthcare safety. Iniatially the dentistry was routinely done without protective gears but after 1991 dental personnel were required to wear gloves, masks ,gown, and protective eyeware . Dentistry is one of the most exposed professions to respiratory diseases eg covid-19.

1. Infection Control
Surface and Equipment Asepsis
Dental Unit Water Asepsis and Air Quality

2. Surface and Equipment
Asepsis
SAS #8

3. Objectives
●Understand the importance of surface and equipment asepsis in
dental settings.
●Identify the common pathogens and routes of transmission in
healthcare environments.
●Differentiate between cleaning, disinfection, and sterilization
processes.
●Recognize appropriate disinfectants and their properties.
●Apply regulatory guidelines and best practices for infection control.

4. Introduction
●Microorganisms in Healthcare Environments
○Diverse population of potentially harmful bacteria and viruses.
○Pathogens can contaminate surfaces and remain active while invisible.
●Importance of Infection Prevention
○Surface cleaning and disinfecting are critical to minimizing disease
transmission.
●Dental Settings
○Close proximity to the patient's nasal and oral cavity increases risk.
○Dentistry-specific modifications to infection prevention are necessary.
●Common Pathogens in Dental Settings
○Bloodborne pathogens: Hepatitis B, Hepatitis C, HIV.
○Respiratory pathogens: Influenza A & B, COVID-19.
○Others: Mycobacterium tuberculosis, Staphylococcus aureus,
Streptococci, HPV.

5. Routes of Transmission in Dental Settings
●Common Routes
○Direct contact: Blood, oral fluids, infectious
materials.
○Indirect contact: Contaminated objects,
equipment, surfaces.
○Droplets or aerosols.
●Focus of this Chapter
○Indirect contact transmission via contaminated
objects, equipment, and surfaces.

6. Pathogens in Dental Settings
●Persistence of Pathogens
○Some survive only in hosts; others
remain virulent on surfaces.
○Influencing factors: Surface material,
temperature, humidity, initial titer.
●Responsibility of Providers
○Keep instruments, equipment, and
surfaces pathogen-free.
●Pathogen Examples
○SARS-CoV-1: Longer persistence in low
temperatures.

8. Environmental Dental Surfaces
●Definition
○Surfaces not in direct contact with patients.
●Categories (level of transmission)
○Clinical Contact Surfaces:
■Direct - spray or splatter
■Indirect - provider’s gloved hand, instruments
■High risk of contamination.
■Examples: Dental chair, instrument
tray, overhead light.
○Housekeeping Surfaces:
■Low risk of contamination.
■Examples: Floors, walls, ceilings.

9. ●Cleaning
○Removes organic materials and visible soils.
○Prepares surfaces for disinfection and sterilization
using detergents and rinse with water

Cleaning, Disinfection, and Sterilization

10. Cleaning, Disinfection, and Sterilization

●Disinfection
○Destroys many pathogens but not bacterial spores.
○Levels of Disinfection:
■High: Destroys all microorganisms and some spores;
chemical sterilants; not to be used on environmental
surfaces
■Intermediate: Kills vegetative bacteria, most fungi, and
viruses, have tuberculocidal claim; may be used for clinical
or housekeeping surfaces with or without blood
■Low: Effective against vegetative bacteria and enveloped
viruses; may be used for clinical and housekeeping
surfaces when not visibly soiled with blood

11. Cleaning, Disinfection, and Sterilization
●Sterilization
○Destroys all microbial life, including spores.
○Most reliable method: Saturated steam under pressure.

12. Properties of an Ideal Disinfectant
●Key Characteristics
○Broad-spectrum efficacy.
○Non-toxic and safe for users and surfaces.
○Non-corrosive and water-soluble.
○Residual antimicrobial effect.
●Pathogen Resistance Hierarchy
○Most resistant: Mycobacterium tuberculosis.
○Targeting highly resistant organisms ensures broad efficacy.

13. Common Disinfectants and Their Uses
●High-Level Disinfectants
○Chemical sterilants.
○Examples: Glutaraldehyde, hydrogen peroxide (7.5%).
○Kills: All microorganisms, some spores.
●Intermediate-Level Disinfectants
○Tuberculocidal claim.
○Examples: Phenolics, iodophors.
○Kills: Vegetative bacteria, most fungi, viruses (enveloped and
non-enveloped).
●Low-Level Disinfectants
○No tuberculocidal claim.
○Examples: Quaternary ammonium compounds.
○Kills: Vegetative bacteria, fungi, enveloped viruses.

16. Clinical Versus Housekeeping Surfaces
●Clinical Contact Surfaces
○Barrier protection recommended.
○Cleaning and disinfection required
between patients.
●Housekeeping Surfaces
○Routine cleaning and disinfection based
on contamination risk.
○High-touch surfaces: e.g. Door knobs,
light switch; More frequent cleaning.
○Minimal-touch surfaces: e.g. Floors,
ceiling; Periodic cleaning.
○Can use detergent and disinfectants
depending on type of contamination

17. Use of Barriers
●Importance of Barriers
○Protect surfaces that cannot be
disinfected.
○Prevent contamination of digital
devices and radiology sensors.
●Types of Barriers
○Plastic wraps, aluminum foil,
FDA-approved materials.
●Guidelines
○Place with clean hands; remove with
gloved hands.
○Change barriers after each patient.
○Does not require surface disinfection
between patients unless soiled
The general considerations for barrier placement during
patient care are indicated below:
●Frequency of potential contact with gloved hands.
●Likelihood of contamination.
●Difficulty of cleaning the surface

18. Cleaning and Disinfecting Procedures
●Two-Step Procedure
○Spray-wipe-spray or wipe-discard-wipe.
●Best Practices
○Use PPE during cleaning.
○Utility gloves recommended for chemical
protection.
○Disinfectant wipes: Clean first, then
disinfect.
●Blood Spills
○Clean promptly; follow federal disposal
regulations.

19. Regulatory Framework
●Governing Agencies
○EPA: Regulates low- and intermediate-level disinfectants.
○FDA: Regulates high-level disinfectants and sterilants.
○CDC: Provides infection prevention guidance.
●Spaulding Classification
○The Spaulding Classification system categorizes medical
instruments and surfaces based on their risk of infection to
patients. The system determines the required level of
decontamination: sterilization, high-level disinfection, or cleaning
and low-level disinfection.
○Critical: Requires sterilization.
○Semi-Critical: Requires high-level disinfection.
○Non-Critical: Requires low-level disinfection or cleaning.

20. Spaulding Classification
1.Critical Items
○Definition: Instruments or devices that penetrate sterile tissue or the vascular
system.
○Requirement: Sterilization.
○Examples: Scalpels, dental burs, surgical instruments.
2.Semi-Critical Items
○Definition: Instruments that contact mucous membranes or non-intact skin but
do not penetrate.
○Requirement: High-level disinfection; sterilization is preferred if feasible.
○Examples: Dental handpieces, reusable impression trays, endoscopes.
3.Non-Critical Items
○Definition: Instruments or surfaces that contact intact skin but not mucous
membranes.
○Requirement: Low-level disinfection or cleaning.
○Examples: Dental chair surfaces, blood pressure cuffs, stethoscopes.

21. Summary and Conclusion
●Key Takeaways
○Proper cleaning, disinfection, and sterilization are essential to infection
control.
○Understand pathogen resistance to select effective methods and
products.
○Use PPE and adhere to regulatory guidelines.
●Goal
○Minimize disease transmission and protect patients and providers.

22. Dental unit water
asepsis and air quality
SAS #9

23. ●Understand the significance of water and air quality in dental
units.
●Identify how biofilms form and their implications in dental practice.
●Explore methods for managing and preventing biofilm formation in
dental unit waterlines (DUWLs).
●Review safety standards and monitoring protocols for DUWLs.
●Learn about effective infection control practices to ensure patient
safety
Objectives

24. Introduction to Dental Unit Waterlines (DUWLs)
●Water entering dental units usually has a low number of
microorganisms present, but the water that passes out of the
dental unit through handpieces, scalers, and air/water syringes is
highly contaminated.
●Dental units supply electricity, air, suction, light, and water to
devices used in dental treatment.
●DUWLs contain narrow-bore tubing (plastic, polymer, silicone
rubber) for water supply.
●Biofilm formation occurs on tubing surfaces, posing potential
infection risks.

25. Introduction
●Environmental Protection Agency (EPA)
○Standard for potable water - no more than a total of 500 colony-forming units
per milliliter (CFU/mL) of noncoliform bacteria.
○Municipal water that enters dental units - 0 to 500 CFU/mL
○Water exiting handpieces, air/water syringe, ultrasonic scales - 100,000 CFU/mL

26. Water Contamination
●Pathogens common in water supply, storage tanks, drain
lines
○Pseudomonas & P. cepacia - important respiratory pathogen for CF
patients
○Legionella spp. - causes respiratory illness
○Acinetobacter, Alcaligenes, Klebsiella, Serratia - G (-) pathogens
○Most common in immunodeficient patient

27. Clinical Application
CDC guidelines : not to use dental unit water as irrigant for oral
surgery (e.g., biopsy, surgeries, extractions, removal of bone)
●Flush water lines and handpieces b/t pts (may help reduce
planktonic microbial count or free-floating microorganisms).
The other is attached to the water line, biofilm (discussed on
the next slide).
●Also will bring fresh supply of chlorinated water.

28. What Are Biofilms?
Definition: Biofilms are heterogeneous communities of microorganisms
that adhere to surfaces and coexist in a moist environment within an
extrapolysaccharide matrix.
●Common microorganisms: Bacteria, fungi, algae, and yeasts.
●Formation stages: Initial attachment → Irreversible attachment →
Microcolony formation → Maturation → Dispersion.
Importance in Dentistry: Biofilms in DUWLs can harbor pathogens like
Legionella, Pseudomonas, and non-tuberculous mycobacteria (NTM).

30. Clinical Implications of Biofilms
Key Risks:
●Potential transmission of waterborne infections to patients.
●Documented cases:
○Legionella pneumophila infection linked to DUWLs.
○Outbreaks of NTM infections in pediatric dental clinics.
Outcomes: Severe complications such as tooth loss, hearing loss, and permanent
tissue damage.

31. Managing Biofilm Formation in DUWLs
Primary Methods:
1.Flushing Waterlines: Routine flushing to reduce planktonic bacteria.
2.Chemical Treatments:
○Daily maintenance tablets/liquids.
○EPA-registered shock treatments.
○Examples: Hydrogen peroxide, ethanol, EDTA, chlorine dioxide
cleaners.
3.Filtration Systems:
○0.2 μm filters upstream of handpieces and syringes.
4.Advanced Treatments:
○Iodine cartridges, D-amino acids, and silver-based solutions
(under investigation).
Note: Manufacturer recommendations must be followed for compatibility
and safety.

32. Independent Reservoirs
●Definition: Self-contained systems for single-chair
or full-practice use.
●Purpose: Isolate dental units from municipal water
supplies.
●Limitations: Require chemical treatments for
effective microbial control.

33. Testing and Monitoring
Why Monitor?
●Ensure compliance with CDC, ADA, and EPA water quality standards.
●Identify microbial loads in DUWLs to prevent outbreaks.
Methods:
●R2A spread plate method (gold standard).
●In-office and outsourced testing systems.
Recommended Levels:
●< 500 CFU/mL for routine dental use (CDC).
●< 200 CFU/mL (ADA guidelines).
●Use sterile water for surgical procedures.

34. Safety Standards and Protocols
Key Recommendations:
●Follow manufacturer’s instructions for
maintenance and treatment.
●Use anti-retraction valves to prevent
backflow contamination.
●Daily flushing of DUWLs: Start of the day
(minutes) and between patients (20–30
seconds).
●Regular microbial testing to ensure
compliance.

35. Summary and Takeaways
●Biofilms pose significant risks in DUWLs, leading to potential patient
infections.
●Regular treatment, flushing, and monitoring are essential to maintain
water quality.
●Adhere to infection control guidelines to ensure patient safety and
compliance.

36. END