Reinforcing the Basics of Infection Control



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The last 2 decades have seen the development and implementation of a number of comprehensive “state-of-the-art” infection control recommendations and regulations. These have been aimed at ensuring high levels of health professional and patient safety in healthcare settings. Although compliance among dental and medical treatment providers continues to increase, when someone does not understand the complete rationale for what is being recommended or required, questions and doubts become increasingly common.
     This article will use the same format as the one that appeared in March 2010 issue of Dentistry Today to focus on representative issues that can present occasional misunderstanding and compliance problems in the areas of hand hygiene and instrument reprocessing. The discussion is designed to use common questions that are asked as a basis for reinforcing both the “what” and the “why” of published infection control recommendations.

Question 1. There have been a number of waterless, alcohol-based hand antiseptics marketed in recent years. I hear from colleagues they are recommended over hand washing for routine use in clinical settings. Does this mean that hand washing is no longer considered effective or acceptable?
You have several acceptable choices for accomplishing effective hand hygiene in your practice. These alternatives are included in the comprehensive 2003 Centers for Disease Control and Prevention (CDC) infection control recommendations for dentistry. Either plain soap or an antimicrobial soap and water can be used for nonsurgical dental procedures, such as examinations, preventive procedures, restorative dentistry, orthodontics, and endodontic procedures. If hands are not visibly soiled or contaminated with blood or other potentially infectious material (ie, saliva, bloody saliva), use of a waterless, alcohol-based hand rub is also acceptable. It is important to note the specific wording of the recommendation: “If hands are not visibly soiled, an alcohol-based hand rub can also be used.”
While the use of an antiseptic agent provides effective antimicrobial activity against overgrowth of normal, commensal, and transient microflora; the basic tenet of hand washing is to clean hands. Several factors must be considered when deciding what approach will be used. These factors include the type of procedures performed in the clinical facility, degree of anticipated contamination during patient treatment, and whether or not residual or persistent antimicrobial activity is needed after hand hygiene procedures. Thus, you can choose to routinely use a liquid soap or antimicrobial antiseptic and water. Use of plain soap is appropriate for removing skin debris and microbial contamination. Since intact skin is a primary barrier, any non-antimicrobial soap considered should contain ingredients to prevent skin irritation and dryness to help preserve epithelial integrity. Optimal properties for use of an antimicrobial antiseptic with water should include broad antimicrobial spectrum of activity, ability to act fast, and a residual, persistent effectiveness.
The key for use of whatever hand hygiene agent that you decide upon is compliance. Several clinical reports published in the medical literature have indicated that the incidence of healthcare-associated infections decreased as healthcare workers (HCW) demonstrated improved hand hygiene practices. Other studies have also shown that compliance increased with use of alcohol-based hand rubs. As such, the 2002 CDC guidelines for hand hygiene in healthcare settings that served as the basis for the 2003 dental recommendations, advocated a combined protocol of hand washing and alcohol-based agents for routine hand antisepsis.

Question 2. Are there any recommendations for the use of hand lotion in clinical settings?
Lotions are recommended to reduce drying of hands and possible dermatitis from glove use. Use of lotions is especially important in healthcare where HCW frequently wash their hands 20 or more times a day, thereby leading to an increased potential for chronic irritation dermatitis. Previously, the overwhelming majority of commercial lotions were petroleum-based. While they can lubricate and replenish keratinized epithelial tissues, these formulations also unfortunately react with gloves being worn (primarily latex gloves) and increase their permeability. Basically, the gloves can become tacky, and thus do not provide the appropriate dexterity needed during treatment. Water-based lotions are far more compatible with gloves, can be absorbed into the skin more rapidly, and have become increasingly available in both the healthcare and public marketplaces. When deciding which lotion to use, consider the possible interaction of the glove type, dental materials, and antimicrobial hand hygiene products with the lotion.

Question 3. What are some of the common errors that can lead to sterilization failure?
There are multiple factors that can adversely affect sterilization cycles in an autoclave, dry heat, or unsaturated chemical vapor sterilizer. Problems that apply to each of these heat sterilizers include the following 6 issues:
1. Improper cleaning of instruments. Cleaning is the basic, critical step in instrument processing because it involves removal of contaminating debris and organic material from an instrument before sterilization. If blood, saliva, and other contamination remain, they can shield adherent microorganisms and potentially compromise the sterilization process.
2. Improper packaging. This factor includes using the wrong type of packaging material for method of sterilization, placing too many instruments in a package, and wrapping items in excessive amounts of packing wrap. If the material used to package instruments is not compatible, or excessive wrap is used, the sterilizing agent (ie, moist heat under pressure, dry heat, unsaturated chemical vapor under pressure) may not be able to appropriately contact instrument surfaces, thereby resulting in a sterilization failure. Also, if the packaging material cannot withstand the high temperatures required for dry heat sterilizers, it may melt and create additional problems with the unit.
3. Overloading the sterilizer. Overloading the chamber can result in prolonged warm-up times needed to reach sterilization conditions, and may also prevent thorough contact of the sterilizing agent with all items in the unit. Not spacing wrapped instrument packages adequately is a common problem observed with sterilization failures. Most sterilizers sold in recent years are provided with racks or trays, which allow a maximal capacity of instrument packages and effective sterilization with prescribed cycles. A number of older units can also be fitted with available racks or trays.
4. Inappropriate sterilization time, temperature, and/or pressure. Issues to consider here include use of inadequate temperature or time during the sterilization cycle and interrupting the total cycle. Human error plays a role here if the sterilizer door is opened during the cycle or timers are incorrectly set, thereby resulting in incomplete sterilization.
5. Inadequate maintenance of sterilization equipment. Routine maintenance as recommended by the manufacturer is critical to the whole instrument processing protocol. Examples of problem areas here are defective control gauges, which may give erroneous readings of conditions inside the chamber and worn door gaskets and seals.
6. Use of improper equipment for sterilization. This potential problem is clearly addressed in the CDC Guidelines for Infection Control in Dental Health-Care Settings—2003, with the recommendation: “Use only FDA-cleared medical devices for sterilization and follow the manufacturer’s instructions for correct use.” Neither household ovens nor smaller toaster ovens meet the stringent criteria required in testing and evaluation as heat sterilizers.

Question 4. What are the basic differences among the variety of chemical indicators available for use in heat sterilization?
Chemical indicators use sensitive chemicals to assess physical conditions (eg, time and temperature) during a sterilization process. Common forms are available as paper strips, labels, and steam pattern cards, which change color when certain temperature, time, and/or pressure conditions are reached during the heat cycle. Since they do not contain bacterial spores as the active agent, chemical indicators are not able to prove that sterilization has been achieved. They are valuable, however, by being able to detect certain malfunctions and can also help to identify procedural errors. Autoclave tape is the historical example of a chemical indicator. It was used for many years as visible proof that items in the chamber had been exposed to a heat sterilization process. Unfortunately, the temperature-sensitive stripes on this tape appear long before sterilizing conditions are reached in the chamber; therefore, this external marker is the least sensitive indicator for heat sterilization.
Recommendations addressing sterilization monitoring continue to include chemical monitoring of cycles. In the comprehensive 2003 CDC guidelines, the following recommendation is made: “Use mechanical, chemical, and biological monitors according to the manufacturer’s instructions to ensure the effectiveness of the sterilization process.” Each load to be sterilized should be monitored with both mechanical and chemical indicators. In a possible event where heat and pressure conditions may not be the same inside and outside the pouch, the guidelines also call for using a chemical indicator on the inside of each package in order to verify that sterilizing vapor has penetrated to reach instruments. A relatively recent innovation has made it easier to accomplish this step. Instrument pouches which contain built-in external and internal multiparameter indicators are now available. Those can provide valuable information to personnel regarding time, temperature, and sufficient exposure of processed instruments to steam.

Question 5. How applicable is “cold sterilization” in today’s world of dental infection control?
Cold sterilization as related to dentistry refers to the practice of immersion (ie, liquid chemical) disinfection used to reprocess reusable semi-critical instruments or items for patient care. Chemical germicides used in this manner have been either glutaraldehydes, hydrogen peroxide-based, or peracetic acid solutions. There are multiple reasons why chemical immersion sterilization is no longer considered appropriate for reprocessing heat-stable medical instruments. First and foremost, virtually every available reusable dental instrument is heat-stable and should be appropriately cleaned, packaged, and sterilized between uses with a heat-based, biologically monitored process, such as a steam autoclave, dry heat sterilizer, or unsaturated chemical vapor sterilizer. The CDC refers to heat sterilization as the method of choice when sterilizing instruments and devices. If an item is heat sensitive, it is preferable to use a heat-stable alternative or disposable item. While chemical sterilants can sterilize items that would be damaged by heat, the process to accomplish this may require 6 to 10 hours of immersion. Other factors have also precluded the routine use of cold sterilization in current infection control protocols, including: (1) sterilized items must be rinsed with sterile water after removal from the solution in order to remove toxic or irritating chemical residues, and (2) a sterilization process using liquid chemicals cannot be verified by biological, spore test monitors.

Question 6. We are thinking about switching our practice to using cassettes as containers for our instruments. What factors should we consider as we discuss this major step?
The procedural shift away from ungloved healthcare personnel using small scrub brushes to routinely clean contaminated instruments at sinks has been dramatic. As more data have accumulated concerning the potential for personnel to be accidentally stuck with sharp, contaminated instruments, the use of cassettes in hospitals; dental, hygiene, and assisting schools; practices; and other healthcare facilities has increased significantly over the years. A central, precautionary reason for this is the long-standing infection control recommendation that contaminated instruments should be handled carefully, and as little as possible, in order to minimize the occurrence of accidental sharp exposures. Depending on how instruments and packages are handled and subsequently loaded into a sterilizer, there is a potential for personnel to be accidentally stuck with a sharp instrument. Using this concept as a starting point for discussion, the following should be included when discussing incorporation of cassettes into a practice setting:
1. A cassette system can substantially reduce direct handling of contaminated instruments before sterilization.
2. Different cassette sizes are available, whereby they can hold complete sets of instruments for single procedures; this eliminates the need to prepare and process multiple packages.
3. When loaded properly, it is very difficult to overload the cassette; instrument rails or racks inside the cassette are designed to hold a certain number of instruments.
4. Damage to instruments during processing in a cassette can be reduced from that noted with use of bags or pouches, because the items are held more securely in place.
5. Perforated cassettes are preferable over completely solid containers, as the latter may not allow steam or chemical vapor to reach the contents for sterilization to occur.

You have heard many times that there are multiple approaches and strategies available to assist in accomplishing recognized infection control goals. As public, health professional, and governmental attention continues to focus on providing a high level of safety for HCW and patients alike, it is quite natural for concerned, committed people to have subsequent questions. Hopefully, this brief discussion has offered useful information addressing some areas that you may be thinking about.F

American Dental Association (ADA). Statement on Infection Control in Dentistry. Accessed on June 30, 2010.
Harte JA, Molinari JA. Cottone’s Practical Infection Control in Dentistry. 3rd ed. Baltimore, MD: Lippincott Williams & Wilkins (Wolters Kluwer Health); 2009.
Kohn WG, Collins AS, Cleveland JL, et al; Centers for Disease Control and Prevention (CDC). Guidelines for infection control in dental health-care settings—2003. MMWR Recomm Rep. December 19, 2003;52(RR-17):1-61. Accessed on July 27, 2010.

Dr. Molinari is currently Director of Infection Control for THE DENTAL ADVISOR in Ann Arbor, Mich. Previously, he served for 32 years at the University of Detroit Mercy School of Dentistry as professor and chairman of the Department of Biomedical Sciences and Director of Infection Control. He continues serving as a consultant for the CDC, ADA Council on Scientific Affairs, Council on Dental Practice. He is currently a member of the Michigan Board of Dentistry. In recognition of his efforts, Dr. Molinari was inducted as an honorary member of the Michigan Dental Association, the International College of Dentists, and the American College of Dentists, and he is a 2009 recipient of the ADA Golden Apple Award. He has published more than 350 scientific articles, text chapters, and abstracts, and he lectures internationally on infectious diseases and infection control. He was the Infection Control section editor for the Compendium of Continuing Education in Dentistry, a member of the editorial board for the Journal of the American Dental Association, and writes a monthly column for Dental Economics. He can be reached via e-mail at

Disclosure: Dr. Molinari is a consultant for Hu-Friedy Manufacturing and for SciCan.