1. Infection Control in Dentistry
Microbiology

2. Questions to think about…..
How can you “break the chain” of infection?
Are there areas of your daily practice where cross-contamination could be happening?
How can you make changes that will prevent cross-contamination in your daily practice?

3. Types of Microorganisms
Pathogenic (causing disease)
Potentially Pathogenic
Non-Pathogenic

4. Some infections only occur in individuals who are immunocompromised because their immune system is unable to fight the potential pathogen. These are called opportunistic infections.

5. Major Groups of Microorganisms
Bacteria
Algae
Protozoa
Fungi
Viruses
Since a number of diseases can be transmitted during routine dental care, it is important to understand the principles behind the infection control recommendations of the CDC and OSAP.

6. Bacteria One celled microorganisms Can live independently
Classified according to their shape
Some are harmless, some are disease-producing (pathogenic)
Some types of bacteria form a capsule that protects the cell; Bacteria with this protective coating are particularly virulent, or disease causing.

7. Viruses
Viruses cause many of the diseases in human beings, but can also infect animals and plants.
Examples of diseases caused by viruses:
Measles
Mumps
Colds
Severe acute respiratory syndrome (SARS)

8. Fungi Defined as plants that lack chlorophyll
Includes mushrooms, yeasts and molds
Oral Candidiasis is the most common yeast infection of the oral cavity.
Candidiasis is caused by Candida albicans
Candida is considered an opportunistic infection, in other words, it usually occurs in someone who’s immune system is not functioning normally.

9. Body Defenses Against Microorganisms/Germs
External natural defenses
skin as mechanical barrier
mucous membrane
cilia – fine microscopic hairs in nose
coughing and sneezing
hydrochloric acid in stomach
others..

10. How are diseases transmitted in the dental setting?
From the patient to the dental worker
From the dental worker to the patient
From one patient to another
From the dental office to the community

11. Transmission can be…
Direct- from an infected person to another person who is not immune,
Indirect- from contact with objects that are contaminated, like surfaces or instruments,
Droplet-from spray or splatter contact with mucous membranes, or contact with aerosols (stay suspended in the air for longer periods of time)

12. The Infectious Process “Chain of Infection”
Infectious agent

13. The Chain of Infection Components
Infectious Agent-any potential pathogen (bacteria, virus, fungi, etc.)
Reservoir-where the pathogen lives (a person, on equipment, surfaces, instruments, etc)
Portal of exit- how the infectious agent leaves its reservoir and reach a new host.
Transmission-direct, indirect, airborne, droplet
Portal of entry- how the infectious agent gets into the new host (bloodstream, mucous membrane, etc.)
Susceptible host-someone who is not immune

14. The chain of infection example
Infectious agent
Hepatitis B
The bloodstream
Unvaccinated
Dental worker
Puncture wound
Bleeding wound
Direct via needle stick

15. What alters normal defenses, making a person a susceptible host?
Abnormal Physical Conditions
Systemic Diseases (diabetes, HIV infection, etc)
Drug Therapy (chemotherapy, steroids, etc.)
Stress
Prosthesis and Transplants (joint or organ replacements)
Poor nutrition

16. What factors influence the development of infection?
The number of microorganisms and
duration of exposure (how many and for how long?)
Virulence of organisms (ability to cause disease; pathogenic properties)
Immune status of the host (body defenses)

17. **Application to Practice**
The goal of an infection control program is to “break the chain” of infection by consistently practicing protocols which would prevent the infectious agent from moving to one host to another and preventing cross-contamination.

18. Cross-Contamination
Defined: The spread of microorganisms from one source to another.

20. Alcohol-based hand rub is standard of care Handwashing …
an action of the past
Alcohol-based
hand rub
is standard of care

21. Personal Protective Equipment
A major component of Standard Precautions
Protects the skin and mucous membranes from exposure to infectious materials in spray or spatter
Should be removed when leaving treatment areas
Personal protective equipment (PPE), or barrier precautions, are a major component of Standard Precautions. Use of rotary dental and surgical instruments (e.g., handpieces, ultrasonic scalers) and air-water syringes creates a visible spray that contains primarily large-particle droplets of water, saliva, blood, microorganisms, and other debris. This spatter travels only a short distance and settles out quickly, landing either on the floor, operatory surfaces, dental health care personnel (DHCP), or the patient.
PPE is essential to protect the skin and the mucous membranes of DHCP from exposure to infectious or potentially infectious materials. PPE should be worn whenever there is potential for contact with spray or spatter and should be removed when leaving treatment areas.
Photo credit: Lt. Col. Jennifer Harte, U.S.A.F. Dental Investigation Service, Great Lakes, IL.

22. Masks, Protective Eyewear, Face Shields
Wear a surgical mask and either eye protection with solid side shields or a face shield to protect mucous membranes of the eyes, nose, and mouth
Change masks between patients
Clean reusable face protection between patients; if visibly soiled, clean and disinfect
A standard surgical mask that covers the nose and mouth is worn to protect the mucous membranes from spatter generated during dental procedures. Eye protection with solid side shields or a face shield should also be worn.
A mask should be changed between patients or if it becomes wet during patient treatment.
Clean reusable face protection with soap and water between patients; if visibly soiled, clean and disinfect.

23. Protective Clothing
Wear gowns, lab coats, or uniforms that cover skin and personal clothing likely to become soiled with blood, saliva, or infectious material
Change if visibly soiled
Remove all barriers before leaving the work area
DHCP should wear long-sleeved disposable or reusable gowns, lab coats, or uniforms that cover skin and personal clothing likely to become soiled with blood, saliva, or infectious material (e.g., when spatter and spray of blood, saliva, or other potentially infectious material to the forearms might occur).
DHCP should change protective clothing when it becomes visibly soiled or as soon as possible if penetrated by blood or other potentially infectious fluids.
All protective clothing should be removed before leaving patient care or laboratory areas.
Photo credit: Lt. Col. Jennifer Harte, U.S.A.F. Dental Investigation Service, Great Lakes, IL.

24. Recommendations for Gloving
Remove gloves that
are torn, cut or punctured
If the integrity of a glove is compromised by tears, cuts, or punctures, it should be changed as soon as possible.
Surgical or examination gloves should not be washed before use, nor should they be washed, disinfected, or sterilized for reuse. Washing of gloves can cause a condition known as “wicking,” or penetration of liquids through undetected holes in the gloves. These circumstances may increase the risk of wound contamination and exposure of the DHCP’s hands to microorganisms from patients. Disinfecting agents, oils, certain oil-based lotions, and heat treatments such as autoclaving may result in deterioration of gloves.
Photo credit: Lt. Col. Jennifer Harte, U.S.A.F. Dental Investigation Service, Great Lakes, IL.
Do not wash, disinfect
or sterilize gloves for reuse

25. Precautions for Surgical Procedures
Sterile Surgeon’s
Gloves
Surgical
Scrub
A higher level of infection control is warranted when performing surgical procedures and includes the following:
Surgical handscrub using an antimicrobial agent.
Use of sterile surgeon’s gloves.
Use of sterile irrigating solutions. The latter includes delivery systems that bypass the dental unit, such as sterile bulb syringes or sterile injection syringes.
Photo credit (top left and at right): U.S.A.F. Dental Investigation Service, Great Lakes, IL.
Photo credit (center): Eve Cuny, University of the Pacific School of Dentistry, San Francisco, CA..
Sterile Irrigating
Solutions

26. Clinical Contact Surfaces
This slide shows some examples of clinical contact surfaces, including a light handle, countertop, bracket tray, dental chair, and door handle (shown by arrows).
Photo credit: Lt. Col. Jennifer Harte, U.S.A.F. Dental Investigation Service, Great Lakes, IL.

27. Housekeeping Surfaces
Examples of housekeeping surfaces are walls, sinks, and floors (shown by arrows).
Photo credit: Lt. Col. Jennifer Harte, U.S.A.F. Dental Investigation Service, Great Lakes, IL.

28. Dental Unit Waterlines and Biofilm
Microbial biofilms form in small bore tubing of dental units
Biofilms serve as a microbial reservoir
Primary source of microorganisms is municipal water supply
Studies have shown that colonies of microorganisms, or biofilms, can form on the inside of the small-bore plastic tubing that transports water within the dental unit to handpieces and air-water syringes. Once formed, a biofilm serves as a reservoir that may dramatically increase the number of free-floating microorganisms in water used for dental treatment.
Most organisms isolated from dental water systems originate from the public water supply and do not pose a high risk of disease for healthy persons. Although a few pathogenic organisms, such as Legionella spp. and Pseudomonas sp., have been found, adverse public health threats have not been documented.
Photo credit, top: CDC Image library. This Scanning Electron Micrograph depicts an E. coli (ATCC 11775) biofilm grown on PC (polycarbonate) coupons using a CDC biofilm reactor. Photo credit, bottom: Illustration from the Center for Biofilm Engineering, Bozeman MT.

29. Sterile Irrigating Solutions
Use sterile saline or sterile water as a coolant/irrigator when performing surgical procedures
Use devices designed for the delivery of sterile irrigating fluids
During oral surgical procedures, microorganisms may enter the bloodstream and other normally sterile areas of the oral cavity (e.g., bone or subcutaneous tissue). For this reason, sterile solutions (e.g., sterile saline or sterile water) should be used as a coolant/irrigator when performing surgical procedures.
Because the tubing cannot be reliably sterilized, conventional dental units cannot reliably deliver sterile water even when equipped with independent water reservoirs. Sterile water delivery devices, such as sterile irrigating syringes, shown here, or bulb syringes should be used to deliver sterile water. Sterile water systems, such as those used with surgical handpieces, bypass the dental unit and use sterile disposable or autoclavable tubing.
Photo credit, top: Lt. Col. Jennifer Harte, U.S.A.F. Dental Investigation Service, Great Lakes, IL.
Photo credit, bottom: Eve Cuny, University of the Pacific School of Dentistry, San Francisco, CA.

30. Saliva Ejectors
Previously suctioned fluids might be retracted into the patient’s mouth when a seal is created
Do not advise patients to close their lips tightly around the tip of the saliva ejector
Backflow, meaning reverse flow, can occur when there is more negative pressure in the patient’s mouth than in the evacuator tubing, for example, when the patient uses the saliva ejector as a straw. When this happens, material from the mouth of a previous patient might remain in the vacuum line of the saliva ejector and be aspirated into the mouth of the next patient being treated.
Although there have been no reports of any adverse health issues, patients should not be instructed to close their lips tightly around the saliva ejector tip during use.
Photo credit: Lt. Col. Jennifer Harte, U.S.A.F. Dental Investigation Service, Great Lakes, IL.

31. Infection Control Program Goals
Provide a safe working environment
Reduce health care-associated infections
Reduce occupational exposures
The goal of an infection control program is to provide a safe working environment for DHCP and their patients.
We can accomplish this by adopting measures that will reduce health care-associated infections among patients and occupational exposures among DHCP.