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After studying this chapter, the student will be able to do the following:
1. Describe safety and risk in terms of common hazards in everyday life and work in a dental office.
2. Appreciate the necessity of recommended vaccines for dental health care providers.
3. Be cognizant of emerging diseases and the precautions necessary for their prevention.
4. Define and appreciate the practice of standard precautions in dentistry.
5. Identify the types of personal protective equipment (PPE) that must be used for the practice of dentistry in the operatory and laboratory.
6. Explain the criteria for selection of PPE during dental procedures.
7. Determine the methods of sterilization or disinfection that can be used to decontaminate each type of instrument or item in the dental operatory or laboratory.
8. Practice appropriate sterilization monitoring when processing dental instruments and devices.
9. Evaluate surface disinfectants that may be used in the dental office.
10. Recall the methods that may be used to prevent cross-contamination during distribution of dental supplies.
11. Describe effective ways to manage contamination caused by aerosols and splatter.
12. Discuss safe handling and disposal of sharp items contaminated with blood or saliva.
13. Appreciate the significance of an office exposure control plan and protocol for managing exposure to blood-borne pathogens.
14. Describe the infectious, physical, and chemical hazards in a dental office.
15. Recognize office and laboratory housekeeping practices that contribute to infection control and safety.
biological indicators (BIs)
class I, IV, and V chemical indicators
exposure control plan
ground fault circuit interrupter (GFI)
high-efficiency particulate air (HEPA) masks
internal indicator strips
measles, mumps, rubella (MMR)
mechanical/digital, chemical, and biological indicators
Occupational Safety and Health Administration (OSHA)
personal protective equipment (PPE)
Safety Data Sheet (SDS)
Spaulding Classification of Inanimate Objects
spray, wipe, spray
tetanus, diphtheria, pertussis (Tdap)
time-weighted average (TWA)
What kind of health and safety issues could be involved in working at a dental office? In general, a dental office is a very safe place to make your livelihood. However, some hazards do require that you take precautions to minimize the risk of accident or injury, either to yourself or to those around you.
Risk is the probability of harm. All of us take chances in everyday life. Do you wear your seat belt? Some people enjoy the thrill of risk taking. Others do not and hence avoid it.
Safety is the opposite of risk; it is the probability of no harm. In reality, nothing is completely safe. People are injured in car accidents every day. Lightning strikes. Bees sting. Some days, it even seems that trouble comes looking for us. In fact, there is a real chance (albeit very, very small) that an airplane will fall from the sky and kill us when we are “safe” in our bed at night. (And you thought passing the next dental materials exam was your biggest worry!) We can reduce the hazards of work and play by using common sense, avoiding excessive risk, and using safety equipment. This chapter discusses many of the risks that are present in the dental office and the ways to reduce the likelihood of harm.
II. Ionizing Radiation
Ionizing radiation, such as that produced by X-ray machines, could potentially involve some risk if it is not handled properly. Precautions for the safe use of ionizing radiation are normally addressed in radiology classes and are not covered in this text.
III. Infection Control
Some of the potential risks in a dental office involve exposure to infectious agents borne in bodily fluids, such as blood or saliva. Taking precautions to protect oneself from these fluids and from those objects contaminated by these fluids will minimize risk to infections.
In 2003, the Centers for Disease Control (CDC) released Guidelines for Infection Control in Dental Health-Care Settings–2003, which is a comprehensive overview of infection control. In March 2016, the CDC released the document Summary of Infection Prevention Practices in Dental Settings. The 2016 document does not replace the 2003 document but summarizes it with a series of handy checklists for the dental care provider. It also contains relevant CDC recommendations since 2003.
The Standard for Occupational Exposure to Bloodborne Pathogens by the Occupational Safety and Health Administration (OSHA) mandates the practice of “universal precautions” in dentistry when a potential exists for exposure to blood-borne pathogens in the dental operatory and laboratory. In 1996, guidelines were issued for precautions for contact with blood and other bodily fluids, including secretions (except sweat) and excretions. These guidelines include and supersede universal precautions and are referred to as standard precautions. Standard precautions require that the same infection control procedures for any given dental procedure or task must be followed for each patient and that all patients and materials must be treated as potentially infectious. Therefore, standard precautions should be used.
A. Recommended Vaccines and Precautions for Emerging Diseases
Health care workers (HCWs) are often at risk for exposure to diseases and spreading diseases. Therefore, HCWs should make sure that they are up-to-date with the following vaccines.
1. Hepatitis B: 3-dose series (first dose, second dose 1 month later, and third dose 5 months after second dose). To ensure immunity, obtain serologic testing for antibodies 1 to 2 months after third dose. If antibodies are not detected, undergo a second 3-dose series.
2. Influenza: 1 dose annually
3. Measles, Mumps, Rubella (MMR): If born in 1957 or later with no serologic evidence of immunity or vaccine, the HCW should obtain 2 doses of MMR 4 weeks apart.
4. Varicella (Chickenpox): If no proof of immunity, vaccination, or history of chickenpox, obtain 2 doses of vaccine 4 weeks apart.
5. Tetanus, Diphtheria, Pertussis (Tdap): After an initial dose of the vaccine, obtain a tetanus and diphtheria every 10 years thereafter.
6. Hepatitis C: At the time of this writing, there is no vaccine for hepatitis C. Harvoni is a recently developed medication for hepatitis C but is extremely expensive.
There are emerging diseases of which the HCW constantly should be aware. One such disease is the highly contagious Ebola virus. Though not typically found in the United States, it was prevalent in West Africa in 2014. A person infected with the virus is not contagious until symptoms appear from 2 to 21 days. Symptoms include fever, muscle pain, diarrhea, bleeding and often death. Because of the seriousness of the outbreak of the disease in West Africa, the CDC recommends that prior to any treatment, patients should be asked if they have travelled outside of the United States within the previous 21 days. If a patient is suspected of having had contact with the virus or has any symptoms of the disease, dental treatment must be avoided and specific CDC guidelines must be followed.
B. Personal Protective Equipment and Barriers
Dental health care providers and patients may be exposed to a variety of infectious diseases. The use of personal protective equipment (PPE) and physical barriers between the body and the source of contamination will inhibit transmission of the infections and reduce the likelihood of harm from chemical and physical hazards. Under its Bloodborne Pathogen Standard, OSHA requires that the dental care provider wear appropriate PPE (gloves, masks, eye protection, and clothing) during all patient care activities involving contact with saliva and blood. The PPE should not be worn out of the clinical treatment area or room. An example of a dental care provider wearing PPE is shown in Figure 20.1.
FIGURE 20.1. Dental care provider wearing required eye protection, gloves, mask, and cover gown.
Appropriate gloves must be worn for each specific dental task that involves direct contact with blood or saliva and when handling items that may be contaminated with these bodily fluids. Types of gloves include sterile surgeon’s gloves, nonsterile exam gloves, overgloves, and utility gloves, as shown in Figure 20.2.
FIGURE 20.2. Types of gloves. A. Sterile surgeon’s glove. B. Nonsterile nitrile exam gloves. C. Overglove. D. Utility glove.
Sterile surgeon’s gloves are recommended for use during invasive procedures, which include surgery and involved periodontal scaling. They are the most expensive type of gloves because of their sterility and the high degree of quality control used during their manufacture. In addition, they are available in actual sizes (i.e., 6, 6½, 7, 7½, etc.).
Nonsterile exam gloves may be worn for examination and nonsurgical procedures that are not invasive and when handling most contaminated objects (instruments, impressions, and dental appliances). They are not subject to the same quality control standards as sterile surgeon’s gloves. Exam gloves are available in sizes ranging from extra small to extra large and as both ambidextrous and right/left sided. In 2016, a glove manufacturer has provided half-size exam gloves (i.e., small, small 1/2, etc.). Exam gloves are the suggested gloves for use by dental personnel during most procedures.
Overgloves are thin copolymer or plastic “food handler” gloves that may be worn over nonsterile exam gloves when it is necessary to touch objects not in the oral cavity, such as patient charts, during patient treatment. However, it is difficult to don overgloves without contaminating the exam gloves. In most instances, therefore, a better alternative is to remove exam gloves and then replace them with new gloves when resuming patient treatment. Overgloves are discarded after use on each patient.
Utility gloves are heavy, nonsterile, puncture-resistant gloves that should be worn during cleaning and processing of contaminated instruments, cleaning and disinfecting of contaminated surfaces, and handling of chemicals. They must be cleaned and disinfected after each use.
Gloves used for treatment (exam and surgeon’s gloves) are available in both natural latex and synthetic materials, such as vinyl, nitrile, and neoprene. In addition, they may be powdered or powder-free. Both exam and surgeon’s gloves must be changed for each patient—or more often if the texture of the glove is modified during use.
2. Hand Washing
Use of gloves during patient treatment does not preclude hand washing. Prior to nonsurgical dental procedures, hands should be washed for at least 15 seconds, rinsed, and dried thoroughly before donning and after removing gloves. Do not wash the gloves because wicking and breakdown of composition may occur. Use of an antimicrobial handwash is preferable, although a milder cleanser may be used if the dental operator experiences skin irritation from the hand-cleansing agent. Avoid long fingernails or wearing rings under treatment gloves. This may contribute to holes or tears in gloves, and they can harbor bacteria because of inadequate cleaning of hands during hand washing. Fungal infections may also occur under rings or artificial nails because of retained moisture.
In October 2002, the Centers for Disease Control and Prevention added to its hand hygiene recommendations an endorsement of 60% to 95% alcohol-based (ethyl alcohol preferred) products for hand cleaning. These products are available as foams, gels, or rinses, and they are applied to the hands and rubbed for at least 15 seconds until the agent is dry. These products are not appropriate, however, when hands are visibly contaminated or soiled. They also must be used and stored away from high temperatures because they are highly flammable.
3. Preventing or Managing Latex Irritation
An awareness of hypersensitivity to latex or other irritants by either the patient or the operator is extremely important so that allergic reactions can be avoided.
a. Latex Allergy in Dental Staff
Gloves worn to protect the hands may cause skin problems. In one study, 15% of dental students developed nonallergic irritation or contact dermatitis from disposable latex gloves that were commonly worn. Sometimes, this results from the talc or cornstarch with which many gloves are dusted, and in some cases, prolonged exposure may result in either immediate or delayed hypersensitivity reactions. Immediate hypersensitivity is indicated by urticaria (hives) and erythema (redness) at the points of contact with the skin minutes after the exposure. The severity of this immediate hypersensitivity may range from a rash to systemic reactions, even including life-threatening bronchospasm, hypotension, anaphylaxis, and death. Contact dermatitis, which occurs from 6 to 72 hours after exposure, is the manifestation of delayed hypersensitivity. If hypersensitivity develops, a nonlatex glove made of synthetic material should be worn. However, it is important to determine if a true latex allergy exists; therefore, one should see an allergist and get an accurate diagnosis.
b. Latex Allergy in Patients
An awareness of latex allergy in patients is extremely important. This knowledge should be gained before beginning any dental treatment by questioning the patient during the medical history review. Risk factors for latex allergy include a history of allergies, multiple surgeries, and frequent contact with latex. For treatment of a patient with known latex allergy, schedule the patient early in the day to minimize exposure to airborne latex powder and residue. In addition, those involved in direct patient care must wear nonlatex gloves, and other dental personnel should wear powder-free gloves. During the dental procedure, avoid the use of any latex-containing items. Common dental products that may contain latex are listed in Table 20.1.
TABLE 20.1. Latex Dental Products
4. Facial Masks and Shields
A mask must be worn by the dental operator during any treatment in which splatter or aerosol is created. The mask should be changed for each patient because its outer surface becomes contaminated either with splatter and aerosol or from the operator touching the mask during dental procedures. Likewise, the mask should be changed during treatment of one patient if it becomes wet from exhaled air and, thus, ceases to act as a filter.
Face masks are available in various styles, as shown in Figure 20.3. Acceptable face masks are composed of synthetic material that filter out small particles and bacteria that contact the mask. Standard masks are not intended to protect health care providers against inhalation of highly infectious aerosols, such as those containing Mycobacterium tuberculosis. In such instances, high-efficiency particulate air (HEPA) masks must be worn. These masks are designed to filter out small particles and are more form-fitting to the face. It may be necessary to check respiratory fit (no leakage around the mask) in cases where complete filtration is required.
FIGURE 20.3. Standard face masks are available in various styles. A. Preformed cone. B. Soft, with head and neck ties. C. Soft, with elastic over-the-ear loops. D. Front and back of HEPA mask, which is more efficient, thicker, and more formfitting than standard masks.
A complete face shield, as shown in Figure 20.4B, protects the face from splatter, but not from aerosol, because of the potential for suction of aerosol up under the shield. Therefore, a mask must be worn under a face shield. If worn, a shield must be cleaned and disinfected between use with each patient.
FIGURE 20.4. Protective eyewear. A. Glasses with side shields. B. Face shield.
5. Eye Protection
Protective eyewear with side shields must be worn by the dental care provider during any patient treatment or procedure in which aerosol, splatter, or projectiles may be generated. This is not only for protection against infectious disease agents but also for protection against objects and chemicals that could damage the eyes.
Hazardous chemicals, such as acids, stannous fluoride, disinfectants, and silver nitrate, can be splashed into the eyes. Ultrasonic and high-speed equipment create a spray of aerosols during use; particulates from broken teeth, amalgam, calculus, pumice, gold, or pieces of burs can be expelled from the mouth at speeds of nearly 60 mph. In the laboratory, personnel are exposed to hazards from rotary equipment, such as grinders; hazardous chemicals, such as disinfectants and developers; and high temperatures. To minimize the consequences of a chemical splash, eye wash equipment should be readily available, especially in the laboratory.
Most potential injuries of these types can be avoided if appropriate eye protection is worn. Acceptable eyewear can include safety glasses with side shields, a face shield, or goggles, as shown in Figure 20.4. Corrective lenses can be incorporated in safety glasses. The American National Standards Institute has issued guidelines for selecting eye protection.
c. Patient Protection
When being treated in a reclining position, the patient not only is exposed to the same hazards as the dental personnel but also is at risk from instruments, syringes, or materials that drop from the practitioner’s hand or off of the delivery tray. Although not mandated, protective eyewear should also be worn by the patient. Unless disposable glasses are provided to the patient, eyewear should be cleaned and disinfected between each use.
d. Curing Light Hazards
Today, dental personnel also face eye hazards from several types of light: ultraviolet (UV) light, visible blue light, and lasers. Especially wavelengths between 320 and 400 nm, UV light can cause cataracts and retinal damage. At one time, UV light was used to activate addition polymerization, but visible blue light (400–500 nm) has now replaced UV light in dental polymerization applications. Although blue light is not inherently hazardous, the high intensity of curing lights can cause injuries to the retina. Protective equipment recommended by manufacturers includes safety shields or specially tinted glasses. The ADA is a good source for information on the efficiency of these protective filters.
When lasers are used, it is important not to direct the laser at any nontarget tissue, especially the eyes, or toward any reflective surface. Special eye protection is required for both the operator and the patient. This eye protection must be matched to absorb the specific wavelength of the laser that is used. Nonreflective instruments and personnel shields are available for use with lasers. Signs are also required in any area where a laser is being used.
6. Protective Attire
Protective attire is the outer layer of clothing worn over underlying clothes. The type and characteristic of protective clothing depends on the exposure that is anticipated. A convenient approach is to use disposable gowns with long sleeves, a high neck, and sufficient length to cover street clothes. This outerwear may be disposable or reusable, and it includes uniforms, clinic jackets, lab coats, and gowns. By OSHA mandate, contaminated reusable attire cannot be laundered at home; it must be laundered in the office or by a commercial laundry service. Protective clothing should be changed daily (or sooner, if it becomes visibly soiled or wet) and should be worn only in the clinical area.
C. Instrument Sterilization and Surface/Equipment Disinfection
1. Degree of Decontamination
The degree of decontamination of a dental instrument or equipment depends on its risk of transmitting infection or disease. To determine which method of decontamination to use, categorize the object as critical, semicritical, or noncritical according to the Spaulding Classification of Inanimate Objects.
2. Critical Objects
Critical objects must be heat sterilized in steam, dry heat, or saturated chemical vapor. This category includes items that may penetrate or touch broken mucous membranes or skin. Examples include all instruments, handpieces, and burs. Before packaging for sterilization, all instruments must be cleaned either ultrasonically or by scrubbing. If instruments cannot be cleaned immediately after use, they should be immersed in a holding solution containing enzymes to help break down protein and keep debris from drying. Follow the manufacturer’s guidelines for cleaning and preparing handpieces for sterilization. Store sterile instruments in their sterile wraps, and unwrap them just before use. If a device has no manufacturer’s guidelines for cleaning and sterilization, it should be treated as a single-use item and may not be reprocessed for patient use.
3. Semicritical Objects
Semicritical objects include items such as radiographic film holders, shade guides, and mouth props that contact, but do not penetrate, mucous membranes. Heat or chemical liquid sterilization (high-level disinfectants) is required for these objects. Heat sterilization is preferred, although chemical liquid sterilization may be necessary for items that may be damaged by heat. Liquid chemicals for sterilization include glutaraldehyde, hydrogen peroxide, and peracetic acid. The long sterilization time (6–10 hours), potential for corrosion, and maintenance of sterility during storage are disadvantages of liquid chemical sterilization.
4. Noncritical Objects
Noncritical objects are those items that do not come in contact with mucous membranes but that are touched or contaminated during dental treatment. These items include the dental unit, switches, handles, radiographic tube heads, the dental chair, and plaster bowls and spatulas.
Intermediate-level disinfectants should be used for the disinfection of noncritical objects. Acceptable disinfectants are those that are registered with the U.S. Environmental Protection Agency (EPA), tuberculocidal, and virucidal. These disinfectants must be virucidal against both lipophilic and hydrophilic viruses. Lipophilic viruses, which are enveloped by lipids, are much easier to kill than are hydrophilic viruses, which are coated with protein. Properties of acceptable surface disinfectants are summarized in Table 20.2.
TABLE 20.2. Properties of Acceptable Surface Disinfectants
Acceptable surface disinfectants include hydrogen peroxide, citric acid, iodophors, phenols, quaternaries, sodium hypochlorite and sodium bromide, and chlorine. Products for surface disinfection are summarized in Table 20.3. Because of their instability, some of these disinfectants must be mixed fresh daily; however, some are premixed and have a 2-year shelf life. You should inquire about all the aforementioned features before selecting the product that is most appropriate for use in your office.
TABLE 20.3. Surface Disinfectant Reference Chart—2011
This resource is based on information from www.osap.org/page/SurfDisinfec2010. OSAP is a nonprofit organization, which provides information and education on dental infection control and office safety. For more information, please call 1-800-298-6727. Organization for Safety & Asepsis Procedures (OSAP), 3525 Piedmont Rd., Bldg. 5, Suite 300, Atlanta, GA 30305, www.osap.org, (410) 571–0003. Fax: (404) 264–1956, Email: office@OSAP.org.
Low-level disinfectants are actually detergents or cleaning agents. Some disinfectants contain detergents, but many do not. This information must be obtained from the manufacturer of the disinfectant. The cleaning agent, whether it is a component of the disinfectant or a separate product, must be used during the initial step in the process of disinfecting surfaces.
Surface disinfectants may be applied by sprays or wipes (see examples in Fig. 20.5). Application from bottled surface disinfectants involves a spray, wipe, spray procedure. The initial spray may be completed with a cleaning agent or a disinfectant that contains a detergent. The surface is then wiped (cleaned), usually with a disposable paper towel. This is followed by a final, light spray with the surface disinfectant, after which the surface is allowed to air-dry for the time recommended by the manufacturer. The spray, wipe, spray procedure is shown in Figure 20.6. If disinfectant wipes are used, use one soaked wipe to first clean the surface. Then, use a new wipe to disinfect the surface and let it air-dry for the time recommended by the manufacturer (usually 5–10 minutes).
FIGURE 20.5. Examples of surface disinfectant. A. Sprays. B. Wipes.