Review Ch 18, 20, 21, 23, 24

Question 1

Why is it necessary to study microbiology in dentistry?

Answer 1

To understand the nature of pathogens (disease-producing microorganisms) and ways to prevent the transmission of disease in the dental office.

Question 2

What are the groups of microorganisms studied, what group is the benchmark for sterilization?

Answer 2

The four major groups are: bacteria, viruses, protozoa, and fungi.
1. Bacteria: single-celled organisms that can be found in various environments
2. Viruses: infectious agents that require a host cell to replicate
3. Protozoa: single-celled eukaryotes that can cause diseases like malaria
4. Fungi: includes yeasts, molds, and mushrooms.

Spores represent the most resistant form of life known. They can survive extremes of heat and dryness and even the presence of disinfectants and radiation. Because of this, they are used to test the effectiveness of techniques used to sterilize dental instruments.

Question 3

What are the shapes used to describe various microorganisms?

Answer 3

Bacteria shapes are spherical (cocci), rod (bacilli) and spiral (spirochetes). Chains of cocci are streptococci and irregular groups or clusters are called staphylococci.

Question 4

What is oral candidiasis?

Answer 4

fungi - candida is a common yeast found in the oral cavity of about half the patient population. Oral candidiasis is caused by the year candida albicans. It is an opportunistic infection, especially those that affect very young, very old, and very ill patients. It’s characterized by white membranes on the surface of the oral mucosa, on the tongue, and elsewhere in the oral cavity. Th lesions may resemble thin cottage cheese; wiping reveals a raw, red, and sometimes bleeding base. It’s treated with topical antifungal preparations.

Question 5

How are antibiotics used to treat various infections? What groups of microorganisms are antibiotics ineffective?

Answer 5

Antibiotics are used to treat bacterial infections by targeting bacterial processes such as cell wall synthesis, protein synthesis, nucleic acid synthesis, etc.

Viruses: antibiotics do not work against viral infections
Fungi: antifungal medications are required
Protozoa: antiprotozoal drugs are used instead

Question 6

What are the differences between aerobic, anaerobic, and facultative anaerobic bacteria?

Answer 6

Aerobic bacteria: require oxygen for growth and survival

Anaerobic bacteria: cannot tolerate oxygen and grow in its absence

Facultative anaerobic bacteria: can grow in both the presence and absence of oxygen

Question 7

Who is at risk for the Zika virus?

Answer 7

Zika virus can be spread from a pregnant woman to her fetus and has been linked to a serious birth defect of the brain called microcephaly in babies.

Question 8

How is SARS CoV2 transmitted?

Answer 8

It is spread by droplets when the infected person breaths, talks, coughs, or sneezes.

Question 9

What types of surfaces are found in a dental office?

Answer 9

Touch surfaces: directly touched and contaminated during treatment procedures. Ex: dental light handles, dental unit controls, etc.

Transfer surfaces: may not be directly touched but are in contact with contaminated items and instruments. Ex: trays, handpiece, suction receptors, etc.

Splash, spatter, and droplet surfaces: housekeeping surfaces that are not actually in contact with members of the dental team, contaminated instruments or supplies. Ex: floors, walls, sinks, etc.

Question 10

What are the purposes of surface barriers?

Answer 10

Surface barriers are used to manage surface contamination to prevent the surface from becoming contaminated. Surface barriers are important for areas that are difficult to clean. They should be resistant of fluids. To prevent contamination of surfaces, to reduce the risk of cross contamination, and to speed up the process of preparing the operatory for the next patient.

Question 11

What is precleaning and what is its purpose in clinical areas?

Answer 11

Precleaning means cleaning before disinfecting. All contaminated surfaces must be precleaned before they can be disinfected.Even a bit of saliva or blood might decrease the effectiveness of the disinfectant. Precleaning reduces the number of microbes and removes body fluids, called bioburben. Precleaning techniques are most effective when used on contaminated surfaces that are smooth and easily accessible.

Question 12

What are the purposes of disinfectants?

Answer 12

Disinfection is intended to kill disease-causing microorganisms that remain on the surface after precleaning. Spores are not killed during disinfecting procedures. The term disinfectant is ised for chemicals that are applied to inanimate surfaces, such as countertops and dental equipment.

Question 13

How long is the soak time to sterilize with a surface disinfectant?

Answer 13

Immersion disinfectants are chemicals on the market that can be used for sterilization or high-level disinfection. The time for sterilization can range from 6 minutes to 30 hours.

Question 14

What information is found on label of a chemical agent?

Answer 14

Active ingredients, instructions for use, warning and precautions, EPA registration number and expiration date.

Question 15

What are synthetic phenol compounds?

Answer 15

Synthetic phenol compounds are EPA-registered intermediate-level hospital disinfectants with broad-spectrum activity, meaning that they kill a wide range of microbes. When diluted properly, phenols are used for surface disinfection, provided the surface has been thoroughly cleaned first.

Question 16

Where are Green infection control protocols not appropriate

Answer 16

PPE - single-use, disposable items. Gloves and masks are not reusable. Washable gowns are an alternative to disposable gowns, but they require energy, chemicals and water to wash.

Question 17

What are critical, semi-critical and non-critical items?

Answer 17

Critical instruments: items used to penetrate soft tissue or bone. Great risk of transmitting infection and must be sterilized by heat.

Semi-critical instruments: touch mucous membranes or nonintact skin. Lower transmission risk. Sterilized by heat or receive minimum high-level disinfection if not heat tolerant.

Noncritical instruments: contact only intact skin. Low risk of infection transmission. Cleaned and processed with EPA registered intermediate or low-level disinfectant.

Question 18

Describe an ideal instrument processing area?

Answer 18

Instrument processing area or sterilization area should be centrally located in the office to allow easy access from all patient care areas. This minimizes the need to carry contaminated items through clean areas of the office, where sterilized instruments, fresh disposable supplies, and prepared trays are stored.

Question 19

Describe ultrasonic cleaners and their use in dentistry?

Answer 19

Used to loosen and remove debris from instruments. These cleaners also reduce the risk for hand injury from cuts and punctures that occur during the cleaning process. When using, always wear puncture-resistant utility gloves, mask, protective eyewear, and protective gown. Process until visibly clean.

Question 20

Why are instruments bagged before sterilization?

Answer 20

Before sterilization, the instruments should be wrapped or packaged to protect them from becoming contaminated after sterilization. Can also be grouped into special setups, such as crown/bridge, amalgam, prophylactic, or composite. Never store sterilized instruments open in a drawer or storage container. Once the sterilization container has been opened, the sterilization of the instrument is compromised.

Question 21

What is sterilization?

Answer 21

Sterilization destroys all microbial forms, including bacterial spores. Sterile is an absolute term; there is no partially sterile, or almost sterile. There are three most common forms of heat sterilization in the dental office: steam, chemical vapor, dry heat.

Question 22

What are the difference types of sterilization used in dentistry? What is most common?

Answer 22

There are three most common forms of heat sterilization in the dental office: steam sterilization, chemical vapor sterilization, and dry heat sterilization.

Steam: an autoclave is used to sterilize dental instruments and other items by means of steam under pressure. This involves heating water to generate steam to produce a moist heat that rapidly kills microorganisms. Four cycles: heat up, sterilize, de pressure, drying. The heat, not the pressure, kills the microorganisms.

Chemical Vapor: similar to autoclaving, except that the combination of chemicals (alcohol, formaldehyde, ketone, acetone, and wtaer) is used instead of water to create a vapor for sterilization. OSHA requires a SDS on the chemical vapor solution.

Dry Heat: operate by heating up the air and transferring that heat from the air to the instrument. This form of sterilization requires higher temperatures than are needed for steam or chemical vapor sterlization.

Question 23

What is the purpose of biological monitoring?

Answer 23

It’s the only way to determine whether sterilization has occurred and all bacteria and endospores have been killed.

Question 24

What is the purpose of a process indicator?

Answer 24

Process indicators are placed outside of instrument packages before sterilization. Examples include autoclave tape and color-change markings on packages or bags. They simply identify instrument packs that have been exposed to a certain temperature; they do not measure the duration or the pressure. They are also known as single-parameter indicators. They are useful in distinguishing between packages that were processed and those that were not processed.

Question 25

What causes contact dermatitis?

Answer 25

Contact dermatitis is an itchy rash caused by direct contact with a substance or an allergic reaction to it. It’s not contagious but it’s uncomfortable.

Question 26

What are the problems with wearing latex gloves in dentistry?

Answer 26

The number of healthcare workers and patients who have become hypersensitive to latex has increased dramatically. Three common types of allergic reactions to latex: irritant dermatitis, type 5 allergic reaction, type 1 allergic reaction.

Latex gloves worn during patient care do not provide adequate protection when one is handling chemicals.

Question 27

What information should be transferred onto a label for a mixed chemical solution?

Answer 27

In Ontario and Canada, a label for a mixed chemical solution must include the product name, a clear description of the solution’s contents, appropriate hazard symbols, precautionary statements, and first aid measures. Additionally, it should have the manufacturer’s name, address, and telephone number, along with the reference to the Safety Data Sheet (SDS) for more detailed information. This labeling ensures compliance with the Workplace Hazardous Materials Information System (WHMIS) and helps maintain workplace safety by providing essential information at a glance.

Question 28

How is Lead foil and scrap amalgam handled in a dental office?

Answer 28

Lead foil: easily recyclable but cannot be disposed in the garbage. Exempt from regulation as a hazardous waste when recycled as a scrap metal, but it must be recycled through a licensed recovery facility.

Scrap amalgam: should be collected and stored in a designated, dry, airtight container. Scrap amalgam that is not recycled must be managed as hazardous waste. The container of scrap amalgam that is recycled must be labeled with the name, address, and telephone number of the dental office and the date on which you first started collecting material in the container.

Question 29

What information is included on a SDS sheet?

Answer 29

The product label for information on potential dangers associated with the chemicals included in the products you use.

They contain health and safety information about every chemical in the office. They provide comprehensive technical information and are an important resource. They describe the physical and chemical properties of a material, health hazards, routes of exposure, precautions for safe handling and use, emergency, and first aid procedures, and spill control.

Question 30

What types of bacteria develop in DUWLs?

Answer 30

Pseudomonas, klebsiella, legionella, and nontuberculous mycobaterium species. Bacteria, fungi and protozoa.

Two communities of bacteria in DUWLs are planktonic (free-floating) and biofilm (microbes attached to the inside walls of the DUWLs).

Question 31

How are bacterial levels reduced in DUWLs?

Answer 31

It can be minimized by self-contained water reservoirs, micro filtration cartridges, and chemical agents.

Question 32

What are the benefits of self contained water units?

Answer 32

Two advantages:
1. Dental personnel can select the quality of water to be used, such as distilled, tap, or sterile.
2. Maintenance of the water system (between the reservoir bottle and the handpiece and syringes) is under the control of the dentist and staff.

Question 33

How does backflow occur when using low volume suctions?

Answer 33

Backflow from low-volume saliva ejectors occurs when the pressure in the patient’s mouth is less than that in the evacuator. When a patient closes their lips around the tip of a saliva ejector, a partial vacuum is created, which can cause backflow to occur. This is a potential source of cross-contamination.

Question 34

What number is bacterial colonies kept below in community water samples?

Answer 34

The public water source has a CFU count of less than 500/ml before entering the DUWLs; once that water enters the DUWLs and colonizes within the biofilm, the cFU can skyrocket. CFU (colony-forming units).

Question 35

What causes DUWLs to form bacterial colonies?

Answer 35

Once the water enters DUWLs, the existing bacteria colonize and multiply, the CFU count can greatly increase.

Intermitten stagnation of water inside the units typically occurs between patients, overnight, and over weekends, allowing the planktonic community of bacteria to attach to the walls of the tube. Water heaters can contribute to increased levels of bacterial colonization.

Question 36

What is the purpose of flushing DUWLs and when should this be done?

Answer 36

Flush waterlines for several minutes at the beginning of the day and longer after weekends. Biofilms cannot be removed by flushing alone. Flushing for 20-30s between patients is recommended by the equipment manufacturer.

Flush every morning for 2 minutes and for 20-30s after each patient treatment.