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Clean Hands

March 1, 2010
Protocol for maintaining proper hand hygiene
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Protocol for maintaining proper hand hygiene

by Lois N. Dryer, RDH, MS

In a 2008 article published in the Journal of the American Dental Association, researchers concluded, “…6% to 25% of providers (general practice dentists) maintain inadequate HH (hand hygiene),” and that “knowledge of the CDC hand hygiene (HH) guideline needs to be heightened. Further education of the dental community is warranted to improve HH compliance, improve efficacy of HH practices, and improve skin health.”12

Although a literature search did not produce similar figures published for any other oral care provider group, a review of the rationale, protocols, and methods of hand hygiene seems advisable.

Dental care providers have a responsibility to adhere to scientifically accepted and evidence–based principles of infection control. Recent United States figures place approximately 150,000 dentists, 90,000 registered dental hygienists, 175,000 dental assistants, and 43,000 dental laboratory technicians, as well as dental students, postdoctoral trainees, hospital residents, and thousands of other support personnel at risk for exposure to potentially infectious agents.12

Hand washing is a measure of personal hygiene and a cornerstone of infection control. For generations, soap and water were the standard of care for removing surface contaminants and visible dirt. The physical process of removing dirt, blood, and normal surface microorganisms is referred to as hand washing, while hand asepsis more accurately describes the destruction of pathogenic microorganisms.6

It has been posited that the use of an antiseptic agent emerged in the early 19th century. In 1822, solutions containing chlorides of lime or soda could eradicate foul odors associated with human corpses, and these solutions could be used as disinfectants and antiseptics.

The U.S. Public Health Service produced a film in 1961 demonstrating hand washing techniques for health–care professionals. Recommendations dictated the hands were to be washed with soap and water for one to two minutes before and after patient contact. The use of antiseptic agents as a rinsing agent was thought to be less effective than hand washing and was therefore recommended only for emergencies and where sinks were not available.

APIC, the Association for Professionals in Infection Control, outlined guidelines that were similar to those of the CDC in 1988 and 1995. However, hand washing and these agents should be used only in emergencies or in areas where recommendations include a more detailed discussion of alcohol–based agents, which supports their use in more clinical settings. In 1995 and 1996, HICPAC, the Healthcare Infection Control Practices Advisory Committee, recommended “that either antimicrobial soap or a waterless antiseptic agent be used upon leaving the rooms of patients with multidrug resistant pathogens.”1

The CDC published its formal guidelines for hospitals, first in 1975 and again in1985, recommending the use of nonantimicrobial soaps for the majority of patient contacts, and the use of an antimicrobial agent in procedures that are invasive or performed on high–risk patients. The use of an alcohol–based agent (solution) was recommended when sinks are not accessible. In 2002, the CDC published the Guideline for Hand Hygiene in Healthcare Settings. Guidelines for Infection Control in Dental Healthcare Settings was released in 2003, and although both position papers have implications for oral health–care providers' hand hygiene practices, the 2003 dental infection control guidelines include a list of areas of concern that were not addressed in previous recommendations for dentistry. In regard to the use HH agents, the CDC placed no more emphasis on the use of alcohol–based products than on the use of soap and water. In fact, alcohol–based products are presented as an alternative method.12

Normal bacteria

Normal skin is colonized with a variety of bacteria, and for the most part the vast majority of microbes found on our bodies are nonpathogenic.2 In 1938, bacteria identified on human hands where divided into two categories — transient and resident.

Transient bacteria, also called contaminating or noncolonizing flora, colonize on the superficial layers of the skin and survive for a limited amount of time. They include microorganisms that come into contact with skin through interactions with patients, equipment, or the environment.9 These are not shown to be present in the majority of people but are of concern because, if pathogenic, they can cause infection in their host or to whom they are transmitted. Mechanical friction or antiseptic agents can remove them. “It is the type of microflora that is transmitted most often when providing care directly to patients and is associated most frequently with health–care associated infections.”12

Resident flora, also known as colonizing or normal flora, attaches to deeper layers of the skin and is more resistant to elimination by washing. The number and type of flora, including Staphylococcus species and diptheroids, varies considerably from one person to another; however, it is relatively consistent for each specific person.3 These flora are opportunistic and, when passed from host to host, can cause infection if the host's resistance is compromised or impaired.8 Considered permanent residents of the skin, they are not readily removed by mechanical friction with plain soaps and detergents but are susceptible to agents that contain antimicrobial ingredients.

In a recently published paper, researchers Fierer, Hamady, Lauber, and Knight of Colorado University, Boulder, found a typical hand has roughly 150 different species of bacteria living on it. Although the researchers detected and identified more than 4,700 different bacteria species across 102 human hands, only five species were shared among all 51 participants. Regular hand washing did not significantly affect the variety of bacteria on the hands.2

The CU–Boulder study also confirmed that standard skin culturing of human skin bacteria, a technique used by many labs, dramatically underestimated the full extent of microbial diversity, and the number of bacterial types found on the palm was three times higher than that found on the forearm and elbow.2 According to Knight, “Some bacteria even protect against the spread of pathogens, and although hand washing altered community composition, overall levels of bacterial diversity were unrelated to the time since the last hand washing. Either the bacterial colonies rapidly re–establish after hand washing, or washing does not remove the bacteria.”2


This study also found a greater assortment of bacteria on the hands of women. It is speculated that the pH of skin might be the reason for the greater assortment, as men's skin is generally more acidic. The results could also be due to gender differences in sweat and oil gland production, frequency of use of moisturizer or cosmetics, skin thickness, or hormone production.

The study went on to state that environmental conditions such as oil production, salinity, moisture, or variable environmental surfaces touched by either hand of an individual impacted the composition of the organisms found on the dominant verses the nondominant hand. Although bacterial communities on dominant and nondominant study hands were different, diversity levels were similar.

Fierer said, “The differences found between dominant and non–dominant hands were likely due to environmental conditions like oil production.”2

The skin is the body's key line of defense against the entry of microorganisms. It can also be a primary means for transmitting infections from one surface to another. Studies have shown that the hands of hospital health–care providers are at risk for persistent colonization with pathogenic flora such as S. aureus, gram–negative bacilli, or yeasts.3 During the simple act of touching a patient's face, bacteria and viruses are transferred. These organisms do not become a part of the practitioner's resident flora, but can remain viable for many hours unless removed.6 As such, proper hand hygiene is necessary to prevent cross–contamination during any phase of dental hygiene care. Hand hygiene protocols vary depending on purpose and indication8 (see Figure 1).

To gauge the effectiveness of specific agents on health–care associated pathogens, trials have been conducted comparing soap and water to antiseptic agents regarding their ability to remove transient versus resident bacteria from hands. Agents are tested according to their intended use according to standard protocols.

The majority of these tests ask volunteers to wash their hands with a plain or antimicrobial soap for 30 seconds to one minute. The shortcoming of these trials is that the average time hospital personnel spend washing is less than 15 seconds. Studies with waterless agents have also come up short, as the required amount of active ingredient (3 ml alcohol) is not rubbed into the hands for the recommended amount of time (30 seconds, followed by a repeat application).3

When interviewed, study participants reported several factors that may have adversely affected adherence to recommended protocols. These were “hand washing agents cause irritation and dryness; sinks inconveniently located; lack of soap and paper towels; insufficient time; lack of knowledge of guidelines and protocols; forgetfulness; and disagreement with the recommendations.”8

Research continues to support the tenet that hand hygiene is the single most important factor in preventing the spread of pathogens and antibiotic resistance in health–care settings.7

There are three categories of hand hygiene for health–care providers — routine hand washing, routine hand asepsis, and surgical hand asepsis.8 As surgical hand asepsis is required for procedures that involve incision, excision, or reflection of tissue, this protocol is not standard for routine dental hygiene treatment.

Proper hand washing

Hand hygiene is divided into preparation, washing and rinsing, and drying, and there is a science to hand washing. Hand cleaning employs vigorous rubbing to create friction and ensures that all surfaces of the hands and wrists are exposed to the disinfectant and thoroughly cleaned in a systematic manner. It is suitable for applying alcoholic hand rub or hand washing with nonmedicated soap and antiseptic hand wash solutions. Hands washed with liquid soap or antiseptic hand wash solutions should be thoroughly rinsed under running water.6

Complete drying of the hands is a key factor in effective hand washing and maintaining skin integrity, as microorganisms can proliferate on damp hands and damaged skin.

Rings and watches prevent effective cleaning of the skin, and because total bacterial counts are higher when rings are worn, they should be removed before washing. All personal jewelry should be removed prior to donning gloves as it may puncture gloves, thus rendering them ineffective. Also, jewelry may become contaminated if worn during dental procedures (under gloves or not) and act as a vehicle for transmitting pathogens out of the office and into the home. (Microbiological studies show that the skin under rings becomes heavily colonized with bacteria, e.g., Staphylococcus aureus.) Artificial nails and chipped nail polish may also harbor bacteria. Artificial nails have been implicated in outbreaks of bacterial and fungal infections in hospital wards. Keep fingernails short, clean, and free of nail polish and artificial nails, and jewelry (except plain, nondecorated wedding rings) should not be worn.5,6

Avoid touching the sink and consider the sink, including the faucet controls, contaminated. Use foot pedals for dispensing agents and water if possible. Do not use bar soap or nondisposable toweling.

Hands must be cleaned immediately before each and every episode of dental treatment or after contact with saliva, blood, or other bodily fluid. This prevents contamination of the patient's oral cavity and face with organisms carried on the dental professional's hands. Hand hygiene performed after an episode of patient care and following removal of gloves minimizes contamination of the environment and oneself.

Agents and their properties

A soap is a detergent–based product that's cleaning activities result in the removal of dirt, soil, and varied organic materials. Containing esterified fatty acids and sodium or potassium hydroxide, it is available as a bar, tissue, leaflet, or liquid. Plain soaps have little or no antimicrobial activity, but if used with specific time frames, they can remove loosely adherent transient bacteria. Nonantimicrobial soaps can cause skin irritation and dryness. Some manufacturers add emollients and humectants to their products to decrease this effect, and the use of a postwashing moisturizer is a consideration. However, when choosing a lotion or cream, it is important to consider the efficacy of the product as well as its potential effect upon glove material. Oil–containing agents may have an adverse effect on the integrity of rubber gloves and efficacy of antiseptic agents.3

The following instructions for washing with soap and water have been adapted from the Mayo Clinic.10

To use soap and water:

  • Wet hands with warm, running water and apply liquid soap or clean bar soap. Lather well.
  • Rub hands vigorously together for at least 15 to 20 seconds. Try singing 'Happy Birthday" oncle slowly or twice quickly as a guide to time.
  • Scrub all surfaces, including the backs of hands, wrists, between fingers, and under fingernails.
  • Rinse well.
  • Dry hands with a clean or disposable towel.
  • Use a towel to turn off the faucet.

Alcohol–based hand rubs

As they are fast acting and cause little skin irritation, these alcohol–based agents may help improve hand hygiene compliance. In studies examining the reduction of antimicrobial–resistant organisms, alcohol–based agents were more effective than hand washing with soap and water. Alcohol levels in agents are expressed as percent by volume.3 Rapidly germicidal, alcohol has no residual activity. However, because of the presumed sublethal effects on certain bacteria, regrowth of organisms on the skin occurs slowly. The addition of a specific antimicrobial agent, such as chlorhexidine or triclosan, to an alcohol medium can result in persistent germicidal activity.

The best antimicrobial efficacy can be achieved with ethanol (60% to 85%), isopropanol (60% to 85%) and n–propanol (60% to 80%). These agents work by denaturing proteins. At 95% concentration, ethanol is the most effective against naked viruses. N–propanol is cited as best against resident bacterial flora.

Chlorhexidine (2% to 4%) and triclosan (1% to 2%) exhibit antimicrobial efficacies that are lower and slower. They pose a risk of bacterial resistance.11 In 2005, because of a concern that chemicals could accumulate in the environment and promote potentially dangerous resistant germs, the FDA established an advisory panel to assess these risks to the general public. The risk of resistant bacteria is theoretical, but several experts cautioned that even the potential risk of resistance may not be worth continued mass marketing of soaps (containing these agents) that have no proven benefit to consumers when used for routine cleaning as compared to soap and water.7

Alcohol (gel/solution) is an effective alternative to hand washing for clean hands, but as alcohol will not remove dirt or kill bacterial spores, hands that are visibly dirty or soiled with blood or other body fluids must be attended to with agents designed to remove soil and transient bacteria. A nonmedicated liquid soap removes dirt and transient microorganisms, rendering hands socially clean. Dryness and irritation have been reported with the use of alcohol–based agents. Skin may become damaged because of repeated exposure to detergents, hot water, low humidity (as in winter), no hand lotion, and poor quality paper towels. Dermal damage can change skin flora, which can result in more frequent bacterial colonization (staphylococci and gram–negative bacteria).

The accessibility of hand hygiene facilities has a direct effect on compliance.3 Alcohol–based hand rubs have the advantage of requiring no paper towels for drying, they can be used chairside, and they are less irritating to hands than soaps. Many products also incorporate a moisturizer. A small number of people develop hypersensitivity to alcohol–based hand rubs. Affected staff should change to an alternative product and seek medical advice from their doctors.6

Certain manufacturers recommend washing hands with soap and water after five to 10 applications of a gel, as some personnel may experience a “build–up” of emollients on their hands after repeated use of alcohol–based products.8

When using an alcohol–based hand sanitizer, choose only products that contain at least 60% alcohol. Apply about a half teaspoon of the product to the palm of the hand. Rub hands together, covering all surfaces, until they're dry. Distribute the alcohol hand rub solution evenly over every part of the hand, fingers, and wrists.10

Lois N. Dreyer, RDH, MS, is an associate professor in the Department of Dental Hygiene, New York City College of Technology.


  1. Todar's Online Textbook of Bacteriology
  2. Fierer N, Hamady M, Lauber L, Knight R. Women Have More Diverse Hand Bacteria Than Men; Science Daily Nov. 4, 2008
  3. “Guidelines for Hand Hygiene in Health Care Settings,” Continuing Education for California Dental Hygienists and Assistants; EliteContinuing Education 2009 Publication
  4. Advisory Panel Says Regular Soap and Water Just as Effective in Preventing Illness By Todd Zwillich, WebMD Health News, Reviewed by Louise Chang, MD Oct. 20, 2005
  5. Daniel S, Harfst S, Wilder R. “Mosby's Dental Hygiene Concepts, Cases and Competencies,” 2nd ed. Mosby/Elsevier
  6. Infection Control Services Limited, Infection Control Manual, Oct. 7, 2008
  7. Zwillich T, WebMD Health News, WebMD, Oct. 20, 2005
  8. Palenik C. “Hand Hygiene; Bring on the Alcohol Rubs,, 6/21/05
  9. Home Infection Control Manual Dentistry Personal Protection Hand Hygiene update Oct 9, 2006
  10. Mayo
  11. Guideline for Hand Hygiene in Health–Care Settings. Recommendations of the Health–Care Infection–Control Practices Advisory Committee and the HPCPAC/SHEA/APIC/IDSA Hand Hygiene Task Force, prepared by John M. Boyce, MD, and Didier Pittet, MD.
  12. yers R, Larson E, Cheng B, et al. “Hand hygiene among general practice dentists, A survey of knowledge, attitudes and practices” J Am Dent Assoc, Vol. 139, No 7, 948–957. 2008

Summary of Hand washing protocols

Routine hand washing
Purpose: To remove soil and transient microorganisms
Methods: Nonantimicrobial soap or detergent and water for 15 seconds
Agents: Liquid soap dispensed using a hands–free device. Avoid bar soaps
Indications: When hands are visibly soiled or contaminated with pertinacious materials such as blood and other body fluids; before and after treating patients (before gloving and after gloving); When touching an object bare–handed that is known or likely to be contaminated with blood or saliva; before replacing defective gloves; before leaving the operatory or laboratory (for example, before eating or after using the restroom).

Routine hand asepsis

Purpose: To remove or destroy transient microorganisms; may also affect normal resident flora.

  • With alcohol–based hand rub, add proper amount to dry hands and then rub hands until alcohol has evaporated (hands and forearms are dry) — use products with known persistent activity.
  • Water and antimicrobial agent/detergent for 15 seconds.


  • Generally contain 60% to 95% ethanol or isopropanol or combination, emollient additive, gel medium, and antimicrobial agent such as chlorhexidine, quaternary ammonium compounds, octenidine, or triclosan.
  • Examples of active agents include alcohols, chlorhexidine, chlorine, hexachlorophene, iodine, chloroxylenol (PCMX), quaternary ammonium compounds, and triclosan.

    Indications: When hands are not visibly soiled or contaminated with pertinacious materials such as blood; routine decontamination of hands in clinical situations; before and after treating patient (before gloving and after gloving); when touching an object bare–handed that is known or likely to be contaminated with blood or saliva; before replacing defective gloves; before leaving the operatory or laboratory (e.g., before eating or after using the restroom).

    Comparison of hand washing and antiseptic hand rubs


    • Effective antimicrobial activity when antiseptic hand washes are used
    • Minimally affected by the presence of organic materials
    • Commonly used technique
    • Allergies to antimicrobial agents are uncommon
    • Nonallergic skin irritations can be prevented or treated through the routine use of hand lotions


    • Frequent hand washing can lead to adverse skin reactions (e.g., irritation, drying, and chapping)
    • Compliance is notoriously low
    • Allergies can occur to select ingredients such as fragrances or preservatives
    • Process more protracted than that of antiseptic hand rubs

    Antiseptic hand rubs


    • Provides superior antiseptic action on visibly clean hands
    • Faster hand asepsis than traditional hand washing
    • Use results in lower incidence of skin irritation and dryness when products contain emollients
    • Greater accessibility because sinks are not required
    • Allergic reactions to product components are rare
    • If widely available, leads to greater hand hygiene compliance