10: Prevention of Disease Transmission in Oral Health Care

Prevention of Disease Transmission in Oral Health Care

Preventing disease transmission in dental hygiene practice requires an understanding of the control of microbial contamination, infection, and disease in the oral health care environment. Implementing and practicing protective measures from the perspective of standard precautions is essential.

Disease Transmission

See the section on “Microbial Virulence and Disease Transfer” in Chapter 9.

Development of an infectious disease

1. Source of microorganism or pathogen (microorganism capable of causing infectious disease)

2. Escape of microorganism from the source

3. Spread of microorganisms to another person

4. Entry of a microorganism into the person

5. Infection

6. Damage to the body—the disease occurs when microorganisms multiply to a harmful level

7. Pathogenic agents and diseases associated with oral health care (Table 10-1)

TABLE 10-1

Pathogenic Agents Important in Oral Health Care




Modified from Miller CH, Palenik CJ: Infection control and management of hazardous materials for the dental team, ed 4, St Louis, 2010, Mosby.

Infection control

1. Reducing the numbers of microorganisms that may be transmitted from individual to individual or from individuals to contaminated surfaces, and vice versa

2. Infection control protocol to reduce or eliminate the likelihood of disease transmission by eliminating one or more factors required for disease transfer (Figure 10-1)

a. Asepsis—absence of infectious materials; achieved by removing or killing microorganisms

b. Disinfection—reducing the number of pathogenic organisms in or on an object, thereby minimizing the potential for disease transmission

c. Engineering controls—devices that reduce the risk of exposure to potentially infectious materials (e.g., self-sheathing needles)

d. Personal protective equipment (PPE)—items designed to protect oral health care workers (OHCWs) from exposure to bloodborne and other pathogens (e.g., gloves, masks, safety glasses, face shields, and barrier gowns)

e. Standard precautions—treating all blood and bodily fluids (including secretions and excretions, except sweat), nonintact skin, and mucous membranes as potentially infectious in all clients; in the oral health care setting, saliva is an important source of contamination, as it is invisible but capable of containing infectious agents that can survive on surfaces for a long period

f. Sterilization—the destruction or removal of all microorganisms in or on an object

g. Work practice controls—procedures that reduce the chance of exposure to potentially infectious materials (e.g., using a one-handed “scoop” technique to recap needles)

h. OHCW-related controls

i. Client-related controls

3. Designed to reduce or prevent the spread of pathogens from:

4. Table 10-2 outlines the mechanisms of the spread and the prevention of diseases

TABLE 10-2

Mechanisms of Disease Spread and Prevention



OHCW, Oral healthcare worker; OHC, oral healthcare.

Data from US Department of Labor, Occupational Safety and Health Administration: Controlling occupational exposure to bloodborne pathogens, Washington, D.C., 1996, 2001, OSHA 3127 (revised).

Infection Control Procedures for Oral Health Care Workers

Health history

1. Obtain, review, and update clients’ health histories at all visits

2. Address specific questions related to present health status, physician care, hospitalizations, surgery, diseases, medications, allergies, current or chronic illness, review of major organ systems, and recent overseas travel

3. Be aware that obtaining health histories will not identify all infectious clients; clients may suppress information purposely or unknowingly (many persons with hepatitis B virus [HBV], hepatitis C virus [HCV], and human immunodeficiency virus [HIV] are asymptomatic)

4. Health history may identify conditions requiring:

5. The Centers for Disease Control and Prevention (CDC) recommends conducting a tuberculosis risk assessment for an oral health care setting and then formulating a prevention program appropriate for its designated risk category; most dental settings will be low or very low risk

Immunizations are recommended for OHCWs

1. Essential component of an infection control program

2. Most effective method to prevent contracting a vaccine-preventable disease

3. Immunizations are recommended for the following diseases, unless evidence of past infection and immunity: hepatitis B, varicella zoster, influenza, measles, mumps, polio, rubella, tetanus, influenza A (H1N1); consult with a primary care physician before vaccination, as some vaccines are contraindicated for immunocompromised and pregnant persons

4. The Occupational Safety and Health Administration (OSHA) policies regarding hepatitis B vaccination

5. Hepatitis B vaccine

a. Two single antigen vaccines available

b. Process

(1) Serologic screening for antibodies to hepatitis B surface antigen before vaccination is not recommended, unless infection is suspected

(2) Pregnancy is not a contraindication for vaccination

(3) A series of three injections in the deltoid muscle given at 0, 1, and 6 months

(4) Seroconversion rates are 95% to 97% in healthy younger adults; lower rates (approximately 70%) in persons over 40 years old, smokers, overweight persons, and those receiving injections in the buttocks

(5) Genetic factors may influence seroconversion rates

(6) Testing for antibody (anti-HBsAg) is recommended after vaccination to ensure protection against HBV; testing should be conducted 1 to 2 months after the final injection

(7) With successful seroconversion, protective antibodies have been sustained for at least 20 years

(8) Failure to seroconvert requires a second series of three injections

(9) Continued failure to seroconvert could signal chronic HBV infection in a person who is unable to produce antibodies; nonresponders should be evaluated by a medical provider

(10) The CDC currently does not recommend a booster injection until further research is conducted on past recipients of vaccine

(11) Minimal side effects of vaccine include injection site soreness, headache, and fever

(12) Individuals with allergies to yeast or iodine (vaccine preservatives) must consult a physician before the vaccination

6. Recommended screenings for OHCWs

Hand hygiene

1. Extremely important disease prevention practice in oral health care

2. Hands are a primary source of microorganisms capable of disease transmission

3. Rationale

4. Use of gloves is not a substitute for routine handwashing

5. Hands must be washed before gloves are put on to minimize organisms that can multiply rapidly when enclosed in a moist, warm environment; bacteria and yeast growth can cause skin irritation

6. Hands must be washed after removal of gloves because defects, tears, and punctures may occur in gloves, permitting microorganisms to be transferred to hands; this also helps remove glove powder, which contains latex protein and other glove chemicals that can elicit irritant contact dermatitis or an allergic reaction in sensitized individuals

7. Watches, bracelets, and rings must be removed to prevent harboring of microorganisms; also, rings may perforate glove materials

8. Nails must be kept short and clean and the cuticles well maintained; artificial nails and nail jewelry are not recommended, since current research has implicated them in disease transmission in hospitals

9. Intact skin is the best protection against infection; this can be achieved by:

10. OHCWs who have open or weeping lesions or dermatitis on hands should not provide client care until the condition resolves, since dermatitis reduces the effectiveness of handwashing and nonintact skin provides a portal of entry for microorganisms

11. Hand hygiene procedures for routine dental hygiene care include:

a. Vigorous lathering of hands using an interlacing finger motion with either an antimicrobial or plain soap for 15 seconds

b. Rinsing with cool to lukewarm water while rubbing hands together for 10 seconds

c. Drying hands with single-use paper towels

d. Using alcohol-based hand rubs as an alternative to handwashing

e. Washing hands between clients, before and after lunch, before and after restroom visits, or any time hands become contaminated

f. Maintaining asepsis by touching only sterile instruments or disinfected surfaces

12. For surgical procedures, an antimicrobial soap with substantivity (prolonged anti-microbial effect) is recommended; chlorhexidine digluconate or triclosan

Personal protective equipment (PPE)

1. Protective barriers used to reduce exposure of mucous membranes, hands, and body of OHCWs to microorganisms and also to prevent injury from chemicals and particles of debris

2. Used during client care, laboratory, disinfection, and sterilization procedures

3. PPE includes gloves, masks, protective eyewear, and protective clothing

4. Sequence for donning PPE: protective clothing, then mask and eyewear, and finally, after handwashing, gloves

5. The employer is responsible for providing and maintaining appropriate PPE for employees

6. Gloves

a. The use of gloves provides a high level of protection for both OHCWs and clients

b. Risks associated with not routinely wearing gloves

c. Protocol for glove use

(1) Wear during intraoral procedures and when in contact with contaminated items or surfaces (e.g., contaminated laundry or waste)

(2) If it is necessary to leave the chairside during client care, remove gloves, and after hand hygiene, don a new pair on returning (prevents contamination of additional surfaces one may touch and also prevents contamination of the client with microorganisms that already may be present on those surfaces)

(3) Ensure that gloves cover the cuff of a long-sleeved gown

(4) Change gloves between clients and during long appointments because defects in gloves increase with use beyond 60 minutes

(5) Do not wash or disinfect gloves; may cause “wicking” or enhanced penetration of liquids through undetected defects in gloves

(6) Remove torn or punctured gloves as soon as possible. Wash hands and don new gloves

(7) Do not apply petroleum-based hand lotion prior to wearing gloves because it degrades latex gloves; for the same reason, do not apply petroleum-based lubricants to client’s lips

d. Types of gloves—See Table 10-3 for glove materials

(1) Nonsterile, ambidextrous gloves in sizes extra-small, small, medium, and large are adequate for most procedures; proper glove fit is important to ensure efficient instrumentation and to prevent hand fatigue and possibly carpal tunnel syndrome

(2) Sterile gloves are recommended for surgical procedures

(3) Use puncture-resistant and chemical-resistant utility gloves to prepare chemicals, handle contaminated instruments, and clean and disinfect surfaces

(4) Overgloves are worn over treatment gloves to prevent cross-contamination of items and surfaces such as pens, charts, and drawers

(5) Heat-resistant gloves are worn when handling hot items (e.g., unloading sterilizers)

e. Dermatitis and latex allergy

(1) Irritant contact dermatitis

(2) Allergic contact dermatitis

(3) Latex allergy

(a) Type I or immediate hypersensitivity within minutes or hours

(b) Allergy to naturally occurring latex proteins

(c) Symptoms: skin (hives, swelling, burning, tightness, itching, redness, tingling), lungs (asthma, wheezing, constriction, coughing, sneezing, rhinitis, angioedema), and other (nausea, vomiting, diarrhea, cramps, hypertension, tachycardia, shock)

(d) Anaphylactic shock and death can occur with subsequent exposures to latex

(e) High-risk individuals for latex allergy include: persons who have had multiple surgeries and persons with spina bifida, urogenital anomalies, spinal cord injuries, and allergies to bananas, kiwis, chestnuts, or avocados

(f) Reductions in exposure to latex proteins are known to decrease sensitivity (important for OHC team to reduce their daily exposure to airborne latex proteins by wearing powder-free, reduced-protein latex or latex-free gloves)

(g) The CDC indicates that OHCWs need to be educated about skin problems that can occur with frequent hand hygiene and the use of gloves

(h) Latex-free environment should be provided to clients and OHCWs with a latex allergy

(4) Procedures for management of persons with latex allergy

7. Masks

a. Purpose

b. Composed of synthetic material that should filter at least 95% of small particles

c. Types of masks

d. Should have a seal against the face to minimize leakage around the margins

e. Maximizing effectiveness and minimizing cross-contamination

8. Protective eyewear

a. Purpose—protect the mucous membranes of the eye from microbial invasion, chemicals, and physical projectiles

b. Risks for unprotected eyes

c. Types of eyewear

(1) Regular glasses offer limited side or top protection and are not recommended

(2) Safety glasses, goggles, or loupes

(3) Face shields

(4) Protective eyewear should be provided to clients

9. Protective (barrier) clothing

a. Purpose

b. Characteristics of protective clothing

c. To maximize effectiveness and minimize cross-contamination

10. Additional barrier protection used when cleaning or performing surgery

11. Laundering of reusable clothing

Oral Health Care Environment and Promotion of Infection Control

Design and equipment selection emphasizes

1. Smooth construction—eliminates knobs, hooks, and crevices

2. Design of client chairs and operator stools that:

3. Avoidance of fabric-covered, coiled, or mechanically retracted tubings

4. Sink faucets and soap dispensers with foot or electronic controls

5. Paper-towel dispenser that is designed to avoid touching hardware or is electronically controlled

6. Plastic-lined waste containers recessed under cabinet, with opening on countertop

7. Surfaces that are compatible with disinfectants and detergents

8. Plastic laminate instead of wood for cabinets and countertops

9. Vinyl flooring and walls that are smooth and seamless

10. Carpeting or wallpaper not recommended

11. Dental unit water lines (DUWLs) that provide:

12. Reduction of airborne microbes

13. Housekeeping surfaces (e.g., walls, cabinets, and floors) should be cleaned and disinfected routinely with detergent and water or with detergents or low-level hospital disinfectants

14. Keep treatment area free of unnecessary or seldom-used equipment and items

Maintaining Asepsis in the Oral Health Care Environment

Items associated with oral health care are classified as:

1. Critical—instruments that penetrate oral soft tissue or bone, enter the bloodstream, or enter other sterile tissues of the mouth (e.g., curet); must be heat sterilized or be single-use (disposable) devices (SUDs)

2. Semi-critical—items that come in contact with mucous membranes (used in the mouth) but will not penetrate soft tissue, contact bone, enter the bloodstream, or enter other sterile tissues of the mouth (e.g., radiographic film holders)

3. Noncritical—items that contact intact skin (e.g., blood pressure cuff)

Maintaining asepsis with the use of chemicals and surface covers

1. Categories of disinfecting or sterilizing chemicals (Table 10-4)

Surface disinfection of clinical contact surfaces

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Jan 1, 2015 | Posted by in Dental Hygiene | Comments Off on 10: Prevention of Disease Transmission in Oral Health Care

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