Dynamic Dental Educators– Infection Control

Infection Control Home Study Course #5008 Dynamic Dental Educators designates this activity for 4 continuing education credits

This activity has been planned and implemented in accordance with the standards of the Academy of General Dentistry Program Approval for Continuing Education (PACE) through the joint program provider approval of Dynamic Dental Educators and Relias Learning. Dynamic Dental Educators is approved for awarding FAGD/MAGD credit. Approval does not imply acceptance by a state or provincial board of dentistry or AGD endorsement, 11/01/2013 to 10/31/2017, Provider ID #300115. The Dental courses are accepted/approved in the following states: AL, AK, AZ, AR, CA, CT, DE, FL, GA, HI, ID, IL, IN, IA KS, KY, LA, ME, MD, MA, MI, MN, MS, MO, MT, NE, NV, NH, NJ, NM, NY, NC, ND, OH, OK, OR, PA, PR, RI, SC, SD, TN, TX, UT, VA, VT, WA, WI, WV. For Florida and California, DDE is an approved provider (Florida Board of Dentistry Approved Provider #50-557; Dental Board of California Registered Provider #3964.) Dynamic Dental Educators is an ADA CERP Recognized Provider. ADA CERP is a service of the American Dental Association to assist dental professionals in identifying quality providers of continuing dental education. ADA CERP does not approve or endorse individual courses or instructors, nor does it imply acceptance of credit hours by boards of dentistry. Concerns or complaints about a CE provider may be directed to the provider or to ADA CERP at www.ada.org/goto/cerp. This continuing education activity has been planned and implemented in accordance with the standards of the ADA Continuing Education Recognition Program (ADA CERP) through joint efforts between Dynamic Dental Educators and Relias Learning.

For assistance, please contact: Relias Learning @ 800-950-4248

Copyright 2003 Dynamic Dental Educators. All Rights Reserved. No portion of this text may be copied, reproduced or used in any way without the written permission of Dynamic Dental Educators.

Our course content is unbiased and free from commercial influence. Everyone involved with the development of this course have no conflict of interest and have no financial relationships with the content of this course. Our home study continuing education courses are only meant for re-licensing purposes. Limited information is provided as an overview of the subject matter and potential risks exist when attempting to incorporate techniques or procedures using limited knowledge and without supervised clinical experience. This course is not intended to be a comprehensive or authoritative source.

Dynamic Dental Educators– Infection Control

Contents Objectives Introduction Infection Control Guidelines in Dental Health Care Facilities

Hand Hygiene Personal Protective Equipment (PPE) Gloves Face and Body Protection Nonregulated Waste and Regulated Biohazardous Medical Waste Sterilization and Disinfection Sterilization Heat Sterilization Monitors Disinfection Surfaces Equipment and Instruments – Critical, Semi-Critical, Non-Critical Sharps Dental Unit Waterlines and Facilities Sterile Surgical Irrigation Dental Laboratory

Other Potentially Infectious Materials (OPIM) Common Infectious Diseases

Hepatitis Strains Hepatitis B and D Hepatitis B Declination Statement Hepatitis C Postexposure Management and Prophylaxis

Microorganism Transmission Accurate and Detailed Patient History Radiographs Extracted Teeth Dental Prostheses Environmental Infection Control Guidelines in Health Care Facilities

Air Water Environmental Surfaces Laundry and Bedding

Conclusion References

Dynamic Dental Educators– Infection Control

Objectives

• Review CDC Infection Control Guidelines in Dental Health Care Facilities

• An overview of sterilization and disinfection

• Procedures and practices that can provide effective protection against infection and prevent occurrences of cross-contamination

• Review physical barriers and standard precautions

• An overview of the diseases which commonly present the greatest risk to and concern among

Dental Healthcare Personnel (DHCP)

• Discuss personal protection equipment and hand hygiene

• Review controls for dental labs, sharps and dental unit waterlines

• Discuss microorganism transmission, extracted teeth, radiographs and dental prostheses

• Present an overview of postexposure management and prophylaxis

• Review CDC Environmental Guidelines for Infection Control in Health Care Facilities.

Dynamic Dental Educators– Infection Control

Introduction Infectious disease is a worldwide health concern and presents a difficult, yet necessary task for the Dental Healthcare Personnel (DHCP). DHCP is defined as all paid and non-paid personnel in the dental healthcare setting who may be exposed to infectious materials from water, air, body substances, contaminated supplies, equipment and surfaces. DHCP includes: dentists, hygienists, assistants, laboratory technicians, students and trainees, contractual personnel and other persons not directly involved in patient care, all who may be potentially exposed to infectious agents.

Because of the unknown nature of many of these diseases and the possibility of non-disclosure on the part of the patient, all persons who come into direct or indirect contact with dental patients should practice methods to prevent the spread of infectious diseases. DHCP should also be familiar with the mechanisms of cross-contamination. Infectious disease can result in medical complications for non-infected patients. In addition, the risk of cross-contamination represents a potential liability for the DHCP.

To reduce both medical and legal risk, all associated personnel in the dental office setting need

to take the appropriate actions to protect patients and themselves. Protective and preventive actions take many forms, and range from simple hand washing to vaccination against communicable diseases.

Advances in infection control have set the stage for modern practices that are now taught as part of all dental school curriculums. Some of these advances include:

• Establishing a relationship between infectious pathogens and the risk of transmission and

cross-contamination in the clinical setting. • The development of more effective heat sterilization techniques.

• The development of vaccines to protect healthcare workers against the risk of contracting

diseases upon exposure.

• Improved guidelines for the proper handling and disposal of sharps and biological hazardous waste.

• The development and publication of standard precautions; a group of infection

prevention practices that apply to all patients, regardless of suspected or confirmed infection status, in any setting in which healthcare is delivered. These practices include: hand hygiene, use of gloves, gown, mask, eye protection or face shield (depending on the potential exposure) and the safe handling of sharps. Standard precautions should be used for the care of all patients, regardless of their current health.

• The identification of modes of transmission for different disease types; airborne,

fluidborne, bloodborne, etc.

• Increased technological advances to create disposable equipment and personal barriers that reduce the risk of transmitting disease to patients.

As a result of these general medical practices, the field of dentistry has become much safer in the clinical setting. This has led to reduced risks of infection and increased safety in the practice of dental medicine for the patient and the practitioner.

However, the practice of infection control does contain a human factor. Despite advancing technology, improved medical research, and greater understanding of the disease process, infection controls are only effective when practiced correctly. Appropriate and effective infection control measures can only be relied upon when they are accepted and practiced by the entire dental community.

Since the majority of the adult U.S. population is treated in dental facilities each year, protection against infection and prevention of cross-contamination is important. The challenge facing the dental community to protect patients and themselves from blood and fluidborne pathogens is immense and requires constant vigilance.

Dynamic Dental Educators– Infection Control

Infection Control Guidelines in Dental Health Care Facilities The CDC updated its Guidelines for Infection Control in Dental Health Care Settings which promote the use of standard precautions rather than universal precautions. Standard precautions includes a group of infection preventatives which may be followed in any setting in which healthcare is delivered. Prevention practices include: hand hygiene, use of gloves, gown, mask, eye protection, or face shield, depending on the anticipated exposure: and the safe handling of sharps. Similar to universal precautions, standard precautions are applied in the care of all patients regardless of their diagnoses of or personal infectious status.

A written protocol for an infection control program needs to be developed and maintained and should be make available to all DHCP in the dental office. The protocol should be updated periodically for instrument selection and processing, operatory sanitation, and post-exposure management of occupational injuries.

Because of the length of the CDC document, not all of the guideline recommendations will be discussed. You may view this document in its entirety at www.cdc.gov/mmwr/preview/mmwrhtml/rr5217a1.htm

Hand Hygiene Frequent hand washing, in any setting, is a key factor in preventing the transmission of infectious microbes. It is the single most important infection control practice in dental care facilities. DHCP should make it a practice to wash their hands thoroughly with soap and water, especially if the hands are contaminated or are visibly soiled, at the start and end of each workday and before and after attending to each patient.

Dry hands thoroughly before donning gloves in order to prevent promotion of bacterial growth and wash again immediately after glove removal. This greatly reduces the risk of cross- contamination occurring when infectious microbes are indirectly transferred from person to person through contact with a carrier, either an animate or inanimate object. If you have exudative lesions or weeping dermatitis of the hand, refrain from all direct patient care and from handling patient care equipment.

In addition to, or in place of hand washing with no visible soil, use alcohol-based hand disinfectants. When applied in the prescribed amounts and rubbed for at least 30 seconds, transient microbes are reduced or eliminated, thus preventing contagion and lessening the risk of cross-contamination.

In some studies, washing with non-antimicrobial soap actually increased the amount of bacteria on the hands. It may also cause considerable skin irritation and dryness.

Alcohol rubs with 60% to 95% alcohol are effective at killing bacteria. Alcohol removes almost all of the gram-negative and gram-positive bacteria, including drug-resistant pathogens. Since alcohol is flammable, store alcohol-based washes away from flame and high-heat areas. Contact dermatitis to alcohol rubs rarely occurs however, workers with respiratory allergies may not tolerate strongly fragranced rubs.

Iodophors are another effective way to remove gram-negative, gram-positive, and some spore- producing bacteria. When used in antiseptic washes, iodophors are not usually sporicidal. Most iodophor solutions contain 7.5% to 10% povidone-iodine. The amount of free iodine increases at lower concentrations, increasing the antiseptic properties of the solution, but the chance of irritation increases. Iodophors are more likely to cause contact dermatitis than other antiseptic hand washes.

Dental offices should consider several factors before deciding on a hand washing product. The first thing to take into account is the efficacy of the product in regards to pathogens. Since hands may be washed as many as 30 times per shift, it is best the product not be overly drying or irritating to the hands. Automated hand washing machines are no more effective than manual washing techniques. Automatic dispensing machines dispense the correct amount of product only 65% of the time. In one study, 9% of dispensers were completely blocked.

Dynamic Dental Educators– Infection Control

Dry and damaged skin can occur from frequent hand washing and become a haven for bacteria. Using hand lotions eases skin drying and decreases areas of damaged skin where bacteria like to thrive. Lotion also helps prevent dermatitis, but since their ingredients can weaken latex gloves, only apply at the end of a workday. Check with the lotion manufacturer for the product’s effect on latex gloves, dental materials and antimicrobial cleansers.

Personal Protective Equipment (PPE)

Personal Protective Equipment (PPE) is the clothing or equipment specially designed to protect from the hazards of exposure to blood and other potentially infectious materials (OPIM) by shielding the skin and mucous membranes of the mouth, nose and eyes. General work clothing such as: uniforms, scrubs, pants and shirts; are not considered to be PPE.

Dental procedures, like any invasive surgical procedure, present a risk for a number of airborne, bloodborne, and fluidborne pathogens. Bloodborne and fluidborne microbes may release into the environment by splatter created during handpiece use, suctioning, rinsing, and other procedures. Additionally, microbes carried in the saliva and blood may become airborne when the aerosolization of infected fluids occurs. Dental dams, high velocity air evacuation and proper work practices help minimize dissemination of droplets, spatter and aerosols.

PPE used most often in the dental setting are: gloves, surgical masks, protective eyewear, face shields, respiratory devices and protective clothing (gowns and jackets) which are intended to prevent exposure to blood, body fluids, OPIM and chemicals which may be used for infection control. Clean reusable PPE with soap and water and if soiled, disinfect between patients. OSHA mandates the use of all these items to reduce the risk of bloodborne pathogen exposure in specified circumstances.

There is an OSHA document entitled ‘Model Plans and Programs for OSHA Bloodborne Pathogens and Hazard Communications Standards’ which contains information about setting up workplace control procedures and plans. This document is in Acrobat format and located at www.osha.gov/Publications/osha3186.pdf

Gloves Gloves are an effective and reliable method of preventing disease transmission and have been used since their introduction to medical practice in the mid-1800s. Changing gloves frequently during procedures, before handling instruments, and between patients, combined with the observation of sterile technique, presents a primary barrier between the infectious contaminant and the DHCP.

Wear gloves whenever there is a potential for contact with mucous membranes, blood, OPIM or germicidal agents and during all pre-clinical, clinical, post-clinical, and laboratory procedures. Discard gloves along with other single use disposable items such as: air/water syringe tips, saliva ejectors, high speed evacuators and prophylaxis cups, brushes and angles; upon completion of treatment on a single patient, when torn or punctured and before leaving laboratories or areas of patient care activities.

Perform hand hygiene procedures before donning gloves and after removal. Never wash gloves before or after use. When cleaning and processing contaminated sharp instruments, needles, and devices, wear heavy duty utility gloves to prevent puncture wounds. When handling hazardous chemicals, wear chemical and puncture resistant utility gloves, along with other appropriate PPE, to prevent injuries caused by chemicals coming in contact with the skin.

Always use proper hand washing procedures prior to putting on gloves, since gloves are only 70% to 80% effective in reducing contamination. Disposable latex and disposable vinyl gloves are equally effective barriers; however, new gloves may be defective so check them prior to wearing.

Wearing gloves directly reduces the risk of contracting hepatitis B, staphylococcal abscesses, herpetic whitlow, and other uncomfortable infections and lesions of the hands. Many of these infections were common before the introduction of the practice of wearing gloves. Most DHCP working today have never seen an outbreak of these infections.

Dynamic Dental Educators– Infection Control

Face and Body Protection Surgical facemasks, disposable gowns, and either protective eyewear or chin length plastic face shields, provide additional physical barriers against infection. When worn properly and disposed of according to biological hazardous waste guidelines, these items can stop the transfer of pathogenic microbes.

Wear PPEs whenever there is potential for aerosol spray, splashing, or spattering of droplet nuclei, blood, chemical or germicidal agents or OPIM. After each patient and during patient treatment, change and dispose of masks if they become moist or contaminated. Clean and disinfect face shields and protective eyewear if contaminated.

Wear protective attire (e.g. reusable or disposable gown or a lab coat) that covers clothing and forearms whenever disinfecting or sterilizing, or performing housekeeping procedures using aerosol spray, chemicals and germicidal agents, or whenever you are potentially splashing infectious agents.

Change protective attire daily and between patients when they become moist or visibly soiled. Remove all PPE used during patient care or laboratory activity when leaving work areas and at the end of the work day.

Place contaminated gowns, masks, gloves, and any expendable surgical material in RED biohazard waste bags. Handle all fluids and associated bodily contaminants with caution and treat as regulated medical biohazardous waste.

Nonregulated Waste and Regulated Biohazardous Medical Waste

The majority of soiled items in the dental office is considered general medical waste and can be disposed with ordinary waste as nonregulated. If the nonregulated waste has been contaminated by blood, excretions, secretions or other bodily fluids, then it must be treated as regulated biohazardous medical waste.

The regulation of biohazardous medical waste is normally defined by federal, state and local guidelines. The guidelines address the generation, storage, transportation, disposal and management of biohazardous medical waste.

Biohazardous medical waste is divided into four major categories:

• Microbiology laboratory waste (cultures and stacks of microorganisms) • Blood bulk, blood products, blood and bloody body fluid specimens • Pathology and anatomy waste • Sharps (needles and scalpels).

Never store all biohazardous medical waste in the same container. Always use containers designed for their category. The containers should be rigid, leak-resistant, moisture proof, sealable to prevent leakage and strong enough to prevent bursting or tearing under normal conditions of use and handling.

Recap needles only by using the scoop technique or a protective device. Never bend or break needles for the purpose of disposal. Place disposable needles, syringes, scalpel blades, or other sharp items and instruments into labeled sharps containers for disposal.

Use single-use disposable instruments such as: prophylaxis angles, prophylaxis cups and brushes, tips for high-speed evacuators, saliva ejectors, air/water syringe tips, and gloves; for one patient only and then discard.

Develop a plan for collecting, containing and disposing of biohazardous medical waste. When biohazardous medical waste is generated, be sure to maintain sanitary conditions to avoid any contamination of the office, personnel and patients. Inform all office personnel of the risks of handling biohazardous medical waste and train them in the appropriate handling and disposal of this waste.

Dynamic Dental Educators– Infection Control

Sterilization and Disinfection Sterilization destroys all forms of viable microorganisms, including highly resistant bacteria. Disinfection inactivates some viruses and destroys or inhibits most pathogenic bacteria while they are in their active growth phase. Disinfection allows the potential for viable pathogens to survive, such as Tubercle bacilli and some viruses including Hepatitis A, B and C, depending on the chemicals used during the disinfection process. The CDC recommends disinfecting surfaces and disinfecting or sterilizing medical equipment. All products used by the DHCP, should be regulated and approved by the EPA and the FDA.

Sterilization

Surgical and semi-critical instruments are dental apparatus which penetrate, or at least come in contact with soft, oral tissue or bone. They must be sterilized after each use. Always clean any debris from all instruments and surfaces after use and prior to either disinfection or sterilization. Scrub items manually or mechanically (using an ultrasonic cleaner) in a container of water with either a detergent or an enzymatic product to remove visible blood and other microscopic infectious material. Follow all label instructions on any chemical cleaning product in use.

Utilize at least one of the following procedures to carry out proper sterilization procedures:

• Steam under pressure (autoclave) • Dry heat • Chemical vapor • Ethylene oxide gas (low-heat) • Disinfectant/sterilant – FDA approved.

After the pre-wash, sterilize heat-tolerant instruments in a steam or chemical autoclave or by dry heat. Dry heat sterilizers are available in static-air and forced-air types. Static-air (oven-type) sterilizers have heating coils on the bottom or sides and heat through natural convection. Forced- air (rapid heat-transfer) sterilizers circulate heat rapidly throughout the chamber at a high velocity, reducing the time needed for sterilization. Wear heavy-duty utility gloves and safety glasses to lessen the risk of

The FDA regulates germicides (chemical agents used to disinfect items and surfaces based on the contamination level) that are used on medical devices. A list of FDA approved sterilants/disinfectants for processing reusable medical and dental devices can be found at www.fda.gov/MedicalDevices/DeviceRegulationandGuidance/ReprocessingofSingle- UseDevices/ucm133514.htm

The following are common factors that influence the effectiveness of sterilization:

• Improperly loading of the sterilizer • Improperly cleaning of instruments • Improperly or excessively packaging instruments • Incorrectly packaging material for sterilization method • Not separating equipment, even without overloading • Improperly timing or setting the temperature of the cycle • Incorrectly operating the sterilizer.

Verify proper functioning of the sterilization cycle of sterilization equipment through the use of a sterilization monitor. Document and maintain test results for 12 months.

Dynamic Dental Educators– Infection Control

Heat Sterilization Monitors There are three types of heat sterilization monitors: mechanical, chemical and biological (spore tests).

Mechanical Monitors

Mechanical monitors display cycle time, temperature, and pressure inside the equipment and are usually included with the sterilization equipment. While correct readings do not ensure sterilization, improper readings immediately indicate a problem with the sterilization cycle.

Chemical Monitors

Internal and external chemical monitors ensure certain parameters have been reached. Internal indicators are placed inside the sterilization package and viewed from the outside of the package. Chemical indicators such as heat-sensitive tape show that the proper temperature has been reached, but do not assure efficacy. Single-parameter indicators are available for steam, dry heat, and unsaturated chemical vapor, while multi-parameter indicators are available only for steam sterilizers.

Biological Monitors (Spore Test)

Biological monitors are the most accepted means of ensuring a successful sterilization process because they directly measure whether biological microorganisms are present. Biological indicators (BI) are more plentiful and more resistant than inorganic contaminants found on patient care equipment, so if the indicator is inactive after sterilization, potential pathogens on the equipment have also been killed.

Testing at least once a week with BI assures the sterilization cycle is functioning properly. An un-sterilized control BI (one not placed in the sterilization equipment) should be incubated with the test sterilized BI after the test BI has completed its sterilization process. The control BI will show positive microbial growth and the test BI should show no growth if the sterilization process was successful. Dispose of the un-sterilized control BI by first sterilizing and then discarding it into a biohazardous waste container.

Choose a BI whenever new sterilization personnel have been trained, when using a new tray or packaging material, after the sterilizer is repaired, and after a change in sterilizer loading procedures. If a sterilizer fails the spore test, do not be use it again until it has been inspected, repaired, and passed three tests in consecutive sterilization cycles.

Disinfection

There are three levels of disinfection defined by the CDC and FDA:

• High-level • Intermediate-level • Low-level.

High-level disinfectants are regulated by the FDA who labels them as sterilants/high-level disinfectants. High-level disinfection kills Mycobacterium tuberculosis var. bovis, bacteria, fungi, viruses and all microorganisms, but not all bacterial spores. This is sometimes called cold sterilization. These germicides are approved for heat-sensitive semi-critical devices which do not penetrate the soft tissue. Do not use them for surface cleaning.

Intermediate-level disinfectants are labeled as an EPA hospital disinfectant with tuberculocidal activity claims. Intermediate-level disinfection kills Mycobacterium tuberculosis var. bovis and other human pathogens, but does not kill bacterial spores. These germicides are considered capable of inactivating a broad spectrum of pathogens and are approved for non-critical devices with visible blood. They may be used for surface cleaning where blood spills have occurred.

Dynamic Dental Educators– Infection Control

Low-level disinfectants are labeled as an EPA hospital disinfectant with NO tuberculocidal activity. Low-level disinfection does not kill bacterial spores or Mycobacterium tuberculosis var. bovis, but does kill some bacteria, some viruses and fungi. When these germicides are labeled as such, they can destroy less resistant bloodborne pathogens like hepatitis B and C, HIV and herpes simplex. Use low-level germicides on non-critical devices with no visible blood, and for surface cleaning where no blood spills have occurred. Follow intended use instructions for all germicides whenever disinfecting items or surfaces and prior to sterilization procedures.

Surfaces

Infectious material can contact many surfaces in the clinical setting. Although surfaces normally contact intact skin and are considered non-critical, they may become a particular concern because of the difficulty in cleaning them and because of their role in cross-contamination. Surfaces should be disinfected that may have become contaminated after completion of a dental treatment using procedures recommended by the CDC.

Occupational Safety and Health Administration (OSHA) recommends using an EPA hospital tuberculocidal disinfectant for intermediate-level decontamination and an EPA hospital disinfectant for low-level decontamination. The germicides should be labeled effective against HIV and hepatitis B (HBV) to decontaminate environmental surfaces.

Examples of these surfaces include:

• Lamp handles • Bracket handles on tables and trays • Hoses and handles • Switches and chair controls • Patient charts and x-rays • Countertops • Dental chairs.

Microbial pathogens can survive on equipment and environmental surfaces from 2 hours to 8 months. Follow an initial surface cleaning of debris and infected matter with a second wetting of disinfectant. Allow extended drying time before contact. Disinfect surfaces between patients using an FDA-approved, EPA registered medical disinfectant.

The EPA registers chemicals used to clean environmental surfaces of contaminants. Lists of approved anti-microbial agents can be found at:

• General antimicrobial agents -www.epa.gov/oppad001/list_a_sterilizer.pdf

• Products effective against tuberculosis - www.epa.gov/oppad001/list_b_tuberculocide.pdf

• Antimicrobial products effective against both HIV and hepatitis B- www.epa.gov/oppad001/list_d_hepatitisbhiv.pdf

• Antimicrobial products effective against hepatitis C- www.epa.gov/oppad001/list_f_hepatitisC.pdf

• Other categories of antimicrobial agents - www.epa.gov/oppad001/chemregindex.htm

To clean the majority of housekeeping surfaces (floors, walls, sinks, etc.) use detergent and water or an EPA-registered hospital disinfectant/detergent, depending on the nature of the surface and the type and degree of contamination. For surface cleaning of blood or bloody saliva, use bleach to disinfect. Mix a daily solution using 1 part bleach to 100 parts water, or 1/4 cup bleach to 1 gallon of water.

Dynamic Dental Educators– Infection Control

Alcohol is an effective disinfectant, but evaporates quickly and may not successfully decontaminate all surfaces. Find a comparison of commonly used surface disinfectants at: www.infectioncontroltoday.com/articles/2000/11/a-comparison-of-commonly-used-surface- disinfectan.aspx

Equipment and Instruments – Critical, Semi-Critical, Non-Critical Using barriers and safe handling practices can maintain the sterile integrity of equipment and instruments in between patients and during patient treatment. Placing disposable protective liners and bags over decontaminated equipment and utilizing foot controls for chairs, lights, suction, and handpieces reduces the risk of cross-contamination when handling with gloves.

Pre-soak and sterilize non-discarded critical instruments, items and devices (forceps, scalpels, bone chisels, scalers, and surgical burs) after each use. Acceptable methods of sterilization include: steam under pressure (autoclave), chemical vapor and dry heat. If a critical item is heat sensitive, then be sure to disinfect with a high-level sterilant/disinfectant and package or wrap and seal upon completion. Label with the date of sterilization and the specific sterilizer used if more than one sterilizer is utilized in the facility. Since these items are used to penetrate soft tissue or bone, they have a high risk of contamination with microorganisms.

Semi-critical instruments, items and devices do not penetrate soft tissue or bone, but do come in contact with oral mucous membranes and non-intact skin, so process them in the same manner as critical instruments. Acceptable methods of sterilization for critical and semi-critical instruments include: steam under pressure (autoclave), chemical vapor, and dry heat. Heat-sensitive semi- critical items can take a high-level disinfectant, followed by packaging or wrapping upon completion. Seal and label these packages as previously described. Treat all high and low speed dental hand pieces, rotary components and dental unit attachments such as: reusable air/water syringe tips and ultrasonic scaler tips in a manner consistent with the same sterilization practices as semi-critical items.

Disinfect or sterilize the devices used to polish, trim, or adjust contaminated intraoral devices and follow office procedures for proper packaging or wrapping. Label with the date and note which sterilizer was used if more than one sterilizer is utilized in the facility. Devices should be re-cleaned, as well as critical and semi-critical dental instruments, if packaging is compromised, then package in new wrap, and sterilize again. Always store sterilized items in a manner so as to prevent contamination.

Clean and disinfect non-critical instruments, items, devices, equipment and surfaces with an intermediate-level disinfectant when visibly contaminated with blood or OPIM. Otherwise, a low-level disinfectant may be used. These items come in contact with soil, debris, saliva, blood, OPIM, but do not come in contact with oral mucous membranes or non-intact skin, therefore, they have a relatively low risk of transmitting infection.

Sharps

Handling of sharps is a primary risk for the dental professional because it is the most common method for exposure to bloodborne pathogens. According to the OSHA Needlestick Safety and Prevention Act, employers must identify and make use of effective and safer medical devices as they become available and allow employees directly involved in patient care to select patient care equipment.

Employers who have employees that are exposed to blood or OPIM and are required to maintain a log of occupational injuries and illnesses must also maintain a sharps injury log. The log must maintain the privacy of the employee and at least contain the following: type and brand of device involved in the incident, location of the incident and a description of the incident.

To prevent infection by accidental needle sticks and other sharps hazards, observe the following practices as standard precautions:

• Recap needles only by using a scoop technique or a protective device

Dynamic Dental Educators– Infection Control

• Never bend or break needles for the purpose of disposal

• Dispose of all sharps in approved, one-way depositor sharps containers clearly marked as BIOHAZARDOUS WASTE

• Empty sharps containers properly when three quarters full.

Use disposable needles, syringes, scalpel blades or other sharp items only once and disposed of in a puncture resistant sharps container as close to the area of use as possible.

When using a non-disposable aspirating syringe with a disposable needle, recap the syringe using the one-handed scoop technique, or with a mechanical device used to facilitate one-handed capping, or an engineered sharps injury protection device. In the scoop technique, the cap is laid on the instrument tray and the needle is guided and scooped into the cap until the cap can be completely seated.

Dental Unit Waterlines and Facilities

Protect non-critical items and surfaces with a disposable impervious barrier if they are likely to be contaminated and are manufactured in a manner preventing cleaning and disinfecting. Change the barriers when visibly soiled or damaged and between patients.

Clean and disinfect all unprotected contact surfaces using a hospital grade, low to intermediate- level disinfectant after each patient. These low-level disinfectants should be labeled as effective against HBV and HIV. Make sure the products used to clean prior to disinfection are clearly labeled and follow all handling and storage instructions.

Waterlines which feed water to high speed handpieces, air/water syringes and ultrasonic scalers or other devices, can become contaminated with fungus, bacteria and microorganisms. This forms a biofilm that acts like a reservoir for production of free floating microorganisms in the water.

The CDC recommends purging dental waterlines and devices with air or flushing with water at the beginning of each clinical day for at least 2 minutes. Do this before changing any attachments and in-between patients to reduce microbe buildup. Flushing does not affect biofilm which may exist in the waterline. Self-contained water systems combined with either in-line filters or chemicals are used to improve waterline quality. Use chemical germicides to ensure biofilms are controlled to keep self-contained water systems free of bacteria.

Patient material can enter the dental water system during a procedure, so dental devices connected to the waterline and used in the patient’s mouth should be operated to discharge water for 20 to 30 seconds at the end of use. This flushes oral microorganisms, blood, and saliva from the system. Even though newer devices are engineered with anti-retraction valves to prevent retraction of fluids, the CDC still recommends flushing the system after each patient. Remember to check with the manufacturer for any maintenance or testing procedures.

Sterile Surgical Irrigation

Sterile solutions, such as sterile water or sterile saline, cool and irrigate soft tissue and bone during oral surgery. Use sterile delivery devices, such as bulb syringe or single-use disposal products to deliver the solution. Microorganisms can enter into the vascular system and other normally sterile areas which support the oral cavity during surgical procedures, increasing the risk for localized or systemic infections. Normal dental units are not capable of delivering sterile water, even when they are equipped with independent water reservoirs, because the waterlines cannot be reliably sanitized. Commercial dental equipment, which bypass the dental unit, can deliver sterile water by using single-use or sterile tubing.

Dental Laboratory

Studies have shown that housekeeping surfaces such as sinks, floors, and walls do not pose a risk for disease transmission within dental healthcare settings. In fact, you need only to clean the

Dynamic Dental Educators– Infection Control

majority of surfaces with detergent and water or an EPA-registered hospital detergent. The manual process of scrubbing and wiping is as critical to disinfection as the quality of any germicide. Use an EPA-registered disinfectant in conjunction with OSHA-required practices for infection control if you suspect contact with infectious material. Otherwise using detergent and water is sufficient.

Splash shields and equipment guards shall be used on dental laboratory lathes. Fresh pumice and a sterilized or new rag-wheel shall be used for each patient. Devices used to polish, trim, or adjust contaminated intraoral devices shall be disinfected or sterilized, properly packaged or wrapped and labeled with the date and the specific sterilizer used if more than one sterilizer is utilized in the facility. If packaging is compromised, the instruments shall be re-cleaned, packaged in new wrap, and sterilized again. Sterilized items will be and stored in a manner so as to prevent contamination.

Prostheses, appliances, and other materials used for their construction should be handled in a manner that prevents DHCP and patients from exposure to infectious agents. If the laboratory is off-site, the dental practice and laboratory should communicate who is responsible for the final decontamination process. Prostheses, impressions, orthodontic appliances and other prosthodontic materials (such as bite registrations, temporary prostheses or occlusal rims) should be thoroughly cleaned and disinfected with an EPA registered intermediate-level hospital disinfectant with a tuberculocidal claim and rinsed before being handled in the laboratory.

Any impressions, appliances or contaminated dental models a dental office sends to a dental laboratory should be sealed in an impervious container and labeled as infectious material for the staff at the dental laboratory.

Laboratories should set up an area for cleaning and disinfecting that is separate from the production area. If laboratory staff are not sure whether materials have been disinfected, the staff should clean and disinfect the materials before handling them. Reusable heat-tolerant items should be heat sterilized before being used again. Items that frequently become contaminated (e.g. water pots) and but do not come into contact with patients should be cleaned and sterilized between uses. Staff should wear full PPE’s throughout the cleaning process. Environmental surfaces should be cleaned or barrier-protected in the same manner as the treatment area.

Other Potentially Infectious Materials (OPIM)

Other Potentially Infectious Material (OPIM) is an OSHA term referring to one of the following:

• Body fluids including saliva in dental procedures, any fluid visibly tainted with blood,

and any body fluids in situations in which differentiating between body fluids is impossible

• Any unfixed tissue or organ, other than intact skin, from a human either living or dead

• Culture mediums or other solutions, blood, organs, and tissues from experimental animals

or cell, tissue or organ cultures from humans or experimental animals which either knowing or likely to contain or be infected with HIV, HBV or HCV.

Common Infectious Diseases

HIV, hepatitis B (HBV) and hepatitis C (HCV) are among the most prevalent concerns for dental healthcare personnel (DHCP). In addition, there is a credible risk of infection from herpes simplex viruses, both type 1 and 2. Modes of transmission vary, so practice the use of personal barriers and observe standard precautions to reduce the risk of infectious disease.

Tissue remnants left on dental equipment or in the clinical environment may carry HIV, HBV, or HCV microbes that can remain intact for several hours. Additionally, the following pathogenic microbial organisms can cause the infection of oral and respiratory passages when present in the dental environment:

• Streptococci, staphylococci, and pneumococci

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• Influenza • Measles and mumps • Varicella-zoster (chicken pox and shingles) • Epstein-Barr virus (infectious mononucleosis) • Norovirus (viral gastroenteritis).

The CDC offers the following recommendations for DHCP exposed to specific infectious disease:

• Conjunctivitis – restrict from patient contact and patient environment contact until the

discharge ceases. • Diptheria – exclude from duty until antimicrobial therapy has been completed. • Hepatitis A – restrict from patient contact, patient environment, and food contact until

seven days after onset. • Hepatitis B – if the worker performs exposure-prone procedures, the worker should wait

for counsel from an expert panel. • Herpes Simplex (herpetic whitlow) – restrict from patient contact and patient

environment contact. • HIV – if the worker performs exposure-prone procedures, they should wait for counsel

from an expert panel. • Measles, Mumps, and Rubella – exclude from duty. • S. aureus active infection – restrict from patient contact, contact with patient

environment, and food handling. • Tuberculosis – exclude from duty until the disease is proved noninfectious. • Varicella – exclude from duty.

Female personnel who are of childbearing age should consider vaccinations for preventable diseases prior to becoming pregnant. In general, pregnant women are no more susceptible to infection than the rest of the population; however, there is a risk of passing the infection on to the fetus.

Dental practices should keep employee health records that include records of immunization, exposure, work-related illness, and results of any tests obtained in screening or control programs. All records should remain confidential.

Hepatitis Strains

Strains of hepatitis pose varying degrees of risk to dental practitioners. There is an available vaccine for HAV, but since the primary mode of transmission is fecal, proper hand washing practices keep this virus under control in dental settings. HEV is transmitted via the same mode; its low occurrence rate in the United States makes the risk of its infection extremely rare.

Hepatitis B and D

Both HBV and HDV may reside in the blood and other bodily fluids, placing dentists, hygienists, and assistants at risk during surgical and routine procedures. Transmission of HBV and HDV is percutaneous and permucosal. HBV has been shown to survive in dried blood on surfaces at room temperature for up to 1 week, but is totally preventable by means of immunization. The CDC and the Advisory Committee on Immunization Practices recommends vaccination against HBV for health care workers, including DHCP.

The Occupational Safety and Health Administration (OSHA) requires that employers make the hepatitis B vaccine available at no cost to workers who have occupational exposure to blood or other potentially infectious material within 10 working days of the employee’s assignment to working duties. Once the vaccination series is complete, a titer test, performed within 1 to 2 months, tests for proper levels of the antibody. Employees should shows a completed hepatitis B vaccination series and a titer test for the hepatitis B surface antibody (HBsAb) that reveals adequate levels of the antibody for immunity. If results of the titer test are negative, the CDC and the ADA recommend a second series of antibody treatments.

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In addition, DHCP should be immunized or have proof of immunization from influenza, measles, mumps, rubella, and varicella-zoster. Consider the option of hepatitis-D (HDV) vaccination, since HDV poses a risk of co-infection with HBV and depends on the presence of HBV to create infection in the host.

Hepatitis B Declination Statement

Employees who choose not to accept the vaccine, must sign a statement of declination of the hepatitis B vaccination. The statement can only be signed by the employee following appropriate training regarding hepatitis B, hepatitis B vaccination, the efficacy, safety, method of administration, and benefits of vaccination, and that the vaccine and vaccination are provided free of charge to the employee. This declination form is located at: www.osha.gov/SLTC/etools/hospital/hazards/bbp/declination.html

Hepatitis C HCV is a dangerous hepatitis strains because of its ability to produce chronic infection that permanently compromises the liver. The prevalence of HCV creates an increased risk of exposure for DHCP. Unfortunately, there is no vaccine for HCV, so personal barriers and standard precautions are the best methods of protection. Of the people who receive needlestick exposure, 3% to 10% will become infected.

HCV lives in blood and other bodily fluids including saliva, and transmits via percutaneous and permucosal routes. Needle sticks, blood splatter, and open wound contamination are the most common means of infection to dental care providers.

HIV (Human Immunodeficiency Virus)

HIV is the virus which causes AIDS. Among healthcare workers, infection control of HIV is always a major concern. Because HIV is recognized as a bloodborne and fluidborne pathogen, exercise standard precautions with all patients, especially those who report HIV infection.

HIV may reside in asymptomatic patients. A dental provider’s best protection is to use personal barrier methods. Transmission of HIV in healthcare settings is possible, but rare; according to the CDC, the risk of becoming infected by needlestick exposure is 0.3%.

Because there is currently no vaccine or cure for HIV, proper sterilization and disinfection procedures are the only methods for reducing the risk of infection. Follow preventative practices with all patients, even those who present no signs of the disease.

Postexposure Management and Prophylaxis

The written exposure control plan in all dental practices documents the policies and procedures that facilitate prompt reporting, evaluation, counseling, treatment, and medical follow-up of all occupational exposures. A post-exposure management protocol should:

• Describe the type(s) of contact with blood or other potentially infections materials that

put dental health professionals at risk of infection • Describe the procedures for reporting and evaluating the exposure • Identify a healthcare professional who is available and able to provide counseling and

medical evaluation. Review the exposure control plan annually and update it to reflect changes in technology which help to reduce or eliminate exposure to bloodborne pathogens. Since no one medical device is effective or appropriate for all circumstances, select devices that will not jeopardize the safety of the patient or employee and will make an exposure incident due to a contaminated sharp less likely to occur.

If someone has been exposed to blood or OPIM, first aid should be administered immediately, if necessary, and report the incident to the designated healthcare professional. Wash the injury,

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including punctures to the skin, with soap and water. Flush mucous membranes with plenty of water.

According to the CDC, a post-exposure report should include the following:

• Date and time of exposure • Details of the procedure being performed • Details of the exposure, including its severity and type/amount of fluid or material • Details whether the source material was known to contain HIV or bloodborne pathogens,

and if so the viral load of the source • Details about the exposed person • Details regarding counseling, post-exposure management, and follow-up.

Microorganism Transmission

DHCP and dental patients can be exposed to bacteria, viruses and microorganisms like HBV, HCV, HIV, herpes, tuberculosis, streptococci and staphylococci in dental settings. These microorganisms can infect the oral cavity and respiratory tract and can be transmitted directly from person to person or through cross-contamination, e.g. person to inanimate object then inanimate object to person. Infection occurs through:

• Direct contact with contaminated blood, fluids or other infectious materials • Indirect contact with contaminated objects (instruments, surfaces, etc) • Contacting droplet spatter propelled a short distance from an infected person • Inhaling airborne microorganisms suspended in the air.

In order for an infection to occur, ALL the following chain of infection events must be present:

• Infectious Agent: bacteria, fungi, viruses • Reservoirs: people, equipment, instruments, water • Port of Exit: secretions, skin, mucosa membrane, droplets • Transmission: direct, indirect, airborne • Post of Entry: mucosa membrane, GI tract, respiratory tract, broken skin, eyes • Susceptible Host: immunosuppressed, medically compromised, elderly.

To prevent disease transmission, effective infection control techniques will break one or more of the links which make up this chain.

Factors influencing the development of infection include:

• An adequate number of a pathogenic organism • Duration of exposure • Virulence of organism • Host general physical health and nutritional status • The immune status of host.

Accurate and Detailed Patient History

Familiarity with each patient is a key method of protection for any medical professional. In cases where an accurate or complete medical history is unavailable, treat patients with the utmost precaution and view them as high-risk individuals.

Likewise, patient self-reporting of medical history, exposure to infections, and knowledge of infectious diseases can sway the accuracy of medical histories. Through no fault of the patient, a DHCP may not be advised of a potential risk until it is too late.

Educating patients to the risks associated with each of the infectious diseases benefits the patient and the dental provider. When patients make informed decisions and are knowledgeable about the risk factors, medical history reporting is more accurate and reliable.

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Radiographs Patients may also be exposed to infection during the exposure of oral radiographs. Organisms remain viable on radiographic equipment for at least 48 hours. Cross-infection may occur in the darkroom, since processor solutions do not kill all of the bacteria on the film. Disinfect radiology and darkroom equipment in the same manner as other environmental surfaces. Wear gloves when opening film packets, and remove them before placing the films into the processor.

Extracted Teeth

OSHA considers extracted teeth as potentially infectious material that should be disposed into medical waste containers. Clean and disinfect any teeth sent to a lab with an EPA-registered, tuberculocidal, intermediate-level hospital disinfectant before they are transported. Return extracted teeth to patients upon their request, without this disinfection process.

Dental Prostheses

A dental clinic is not the only setting where people risk infection. Materials sent from dental offices to dental laboratories may contain microorganisms which can cause bacterial contamination, along with viral contaminants. Some microorganisms include: streptococcus, staphylococcus, and E. coli. Several viruses, such as hepatitis B and HIV, may also spread by indirect contact.

Contact with dental prostheses can be a common means of cross-contamination. Scrub dentures with a soft toothbrush and soap or disinfectant solution, or soak them in chemical agents using an ultrasonic cleaner. This decreases the number of contaminating organisms. Dentures that are immersed in disinfectant usually contain fewer microorganisms than those that are brushed.

Unfortunately, some disinfectants, such as sodium hypochlorite, have deleterious effects on dentures and may cause bleaching. The ADA recommends using iodophors for disinfection of prostheses, although some studies have shown that biocides are less effective in removing microorganisms than other solutions. Chlorhexidine is used in dentistry as a preventative agent and Amosan is indicated as a mouthwash. These cleaners have few side effects and a very low toxicity.

Other studies report soaking techniques are as effective as using biocides. One study found that scrubbing first with 4% chlorhexidine and then immersing dentures in 4% chlorhexidine gluconate, Amosan, or 1% sodium hypochlorite for 10 minutes was effective in reducing microbial growth.

Environmental Infection Control Guidelines in Health Care Facilities

The CDC has published Guidelines for Environmental Infection Control in Health Care Settings. The guidelines are not specific to dental offices, but may enhance controlling infection within dental environments.

Because of the length of the CDC document, not all of the guideline recommendations are discussed here. You may view this document in its entirety at www.cdc.gov/mmwr/preview/mmwrhtml/rr5210a1.htm

Air • Prevent dust accumulation by cleaning air-duct grills in accordance with facility-specific

procedures. • Seal windows with centralized HVAC systems.

• Do not use rooms with through-the-wall ventilation for airborne infection isolation (AII) or

protective environment (PE).

• HVAC systems should never be shut down in patient-care areas except for repair, emergency testing, or new construction.

Dynamic Dental Educators– Infection Control

Dynamic Dental Educators– Infection Control

Water Controlling the Spread of Waterborne Microorganisms • Eliminate contaminated water or fluid reservoirs wherever possible. • Avoid placing decorative fountains or fish tanks in patient care areas. If they are used in

public areas, ensure they are cleaned and maintained regularly. Routine Prevention of Waterborne Microbial Contamination within the Distribution System • Maintain hot water temperature at the return at the highest temperature allowed by state

codes and maintain cold water temperature below 68 degrees Fahrenheit. • Maintain constant recirculation in hot-water distribution in patient care areas.

Ice Machines and Ice • Do not store pharmaceuticals or medical solutions on ice intended for consumption. • Do not handle ice directly by hand and wash hands before obtaining ice.

Environmental Surfaces

Cleaning and Disinfection of Environmental Surfaces • Select EPA-registered disinfectants, if available. • Do not use high-level disinfectants for non-critical instruments or surfaces. • Avoid using aerosols or cleaners that produce a mist for cleaning large surfaces in patient

areas. Cleaning Up Spills of Blood and Body Substances • Promptly clean up spills of blood or infectious materials. • Use EPA registered hospital disinfectants labeled tuberculocidal (intermediate level) to

decontaminate spills of blood and other body fluids. • Clean visible material with absorbent disposable materials, and discard waste in labeled

containers. • Swab the area with cloths or paper towels wet with disinfectant and allow to dry. • Use EPA registered sodium hypochlorite, if available. If not available, use 1:100 dilution

(500-615 ppm available chlorine) to decontaminate nonporous surfaces after cleaning a spill of blood or body fluids in patient areas or 1:10 dilution (5000 – 6150 ppm available chlorine) if the spill involves large amounts of blood or body fluids.

Carpeting and Cloth Surfaces • Spot-clean blood or body substance spills immediately. • Replace carpet where a blood or body substance spills. • Make sure carpet is dry to prevent the growth of mold and fungi.

Laundry and Bedding

• Employers are required to launder employees’ personal protective garments or uniforms that

have been contaminated with blood or possibly infectious materials. • Handle contaminated textiles with care to avoid air, surface, or person contamination. • Bag or otherwise isolate contaminated clothing using leak-resistant containers.

Conclusion

Infectious diseases present a real risk to all DHCP and great care should be exercised to prevent disease transmission and cross-contamination by dental care workers. All personnel should be trained in proper infection control procedures and maintain a safe workplace for both personnel and patients.

Use of standard precautions and proper handling of biohazardous waste should be important training points along with ongoing education for anyone who may have direct or indirect patient contact.

Dynamic Dental Educators– Infection Control

References American Dental Association (ADA) – Infection Control - www.ada.org/en/member-center/oral- health-topics/infection-control-resources

ADA – Sterilization and Disinfection of Dental Instruments - www.ada.org/~/media/ADA/Member%20Center/FIles/cdc_sterilization.ashx

Centers for Disease Control and Prevention (CDC) - Regulatory Framework for Disinfectants and Sterilants - www.cdc.gov/mmwr/preview/mmwrhtml/rr5217a2.htm

CDC - Recommended Infection Control Practices for Dentistry - www.cdc.gov/OralHealth/InfectionControl/guidelines/index.htm

CDC – Guidelines for Disinfection and Sterilization in Healthcare Facilities - www.cdc.gov/hicpac/Disinfection_Sterilization/4_0efficacyDS.html

CDC - Viral Hepatitis Strains - www.cdc.gov/hepatitis/index.htm

CDC – HIV/AIDS - www.cdc.gov/hiv/default.html

CDC - Surgical Site Infection - www.cdc.gov/HAI/ssi/ssi.html

CDC - Guideline for Infection Control in Healthcare Personnel - www.cdc.gov/hicpac/pdf/InfectControl98.pdf

CDC – Guideline for Isolation Precautions: Preventing Transmission of Infectious Agents in Healthcare Settings - www.cdc.gov/hicpac/pdf/isolation/Isolation2007.pdf

CDC - Protecting Healthcare Personnel - www.cdc.gov/HAI/prevent/ppe.html

CDC – Infection Control - Backflow Prevention and the Dental Operative Unit - www.cdc.gov/oralhealth/infectioncontrol/factsheets/backflow.htm

CDC - Hand Hygiene in Healthcare Settings - www.cdc.gov/handhygiene

CDC - Guidelines for Environmental Infection Control in Health-Care Facilities - www.cdc.gov/mmwr/preview/mmwrhtml/rr5210a1.htm

CDC - Occupational HIV Transmission and Prevention among Health Care Workers - www.cdc.gov/hiv/risk/other/occupational.html

CDC - Infection Control in Dental Settings Fact Sheets - www.cdc.gov/Oralhealth/infectioncontrol/factsheets

CDC - National Health and Nutrition Examination Survey – Dental Examiners Procedures Manual - www.cdc.gov/nchs/data/nhanes/nhanes_03_04/DentalExaminers-2004.pdf

Infection Control Today – A Comparison of Commonly Used Surface Disinfectants - www.infectioncontroltoday.com/articles/2000/11/a-comparison-of-commonly-used-surface- disinfectan.aspx

Environmental Protection Agency (EPA) - Selected EPA Registered Disinfectants - www.epa.gov/oppad001/chemregindex.htm

Food and Drug Administration (FDA) - Cleared Sterilants and High Level Disinfectants for Reusable Medical and Dental Devices -

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www.fda.gov/MedicalDevices/DeviceRegulationandGuidance/ReprocessingofSingle- UseDevices/UCM133514

Life Extension – Hepatitis B – www.lef.org/protocols/infections/hepatitis-b/page-01

Occupational Safety and Health Administration – Revision to OSHA’s Bloodborne Pathogens Standard - www.osha.gov/needlesticks/needlefact.html

OSHA- Hepatitis B Declination Statement - www.osha.gov/SLTC/etools/hospital/hazards/bbp/declination.html

OSHA Dentistry Safety and Health Topics - www.osha.gov/SLTC/dentistry/index.html

OSHA Bloodborne Pathogens and Needlestick Prevention - www.osha.gov/SLTC/bloodbornepathogens/index.html

PubMed.gov – Infection Control in Dental Radiography - www.ncbi.nlm.nih.gov/pubmed/9518860

PubMed.gov – The presence and identification of organisms transmitted to dental laboratories - www.ncbi.nlm.nih.gov/pubmed/2202822

Dentistry Today – Dental Laboratory Asepsis - www.dentistrytoday.com/infection-control/1325