Cleaning, disinfecting, and sterilization are the most critical elements of infection control to keep your patients and staff safe. Although it may be second nature, maintaining your equipment and instruments should be placed at the top of your priorities. When it comes to sterilization, consider the mechanism of sterility best suited for your practice. When choosing a sterilizer for your office, type, function, make, and capacity are important factors.
The dental industry uses several different types of sterilizers or autoclaves. Steam, dry-heat, and chemical vapor sterilizers are common. Every kind of sterilizer has pros and cons. Cost, size, ease of use, and environmental impact can dictate which is suitable for your office. Also, consider the different types of products that must be sterilized for your practice, critical, semi-critical, and heat tolerant.
Autoclaves, or steam sterilizers, are the most recognized sterilization for the dental office's critical- and semi-critical devices. Autoclaves are nontoxic and highly effective at killing bacterial spores. Three common types of autoclaves include gravity displacement, pre-vacuum, and steam flush pressure pulse (SFPP).
Steam sterilization emits steam at a particular temperature and specific pressure for an appropriate time. To achieve the microbicidal activity, temperatures must reach either 250°F for 30 minutes in a gravity displacement or 270°F for four minutes in a high-speed pre-vacuum sterilizer, depending on the make and model of the machine. These two types of autoclaves represent the basics and most common of steam sterilization.
Gravity displacement autoclaves create steam inside the chamber while displacing ambient air and forcing it out of an exhaust valve. This autoclave is practical for items not wrapped or packaged since steam does not need to penetrate but only comes in contact and settles on the surface. This type of autoclave is not sensible for dental operations since the CDC recommends that instruments be packaged or wrapped for sterilization. On the other hand, a pre-vacuum autoclave pumps ambient air out of the chamber while filling the chamber with steam. The vacuum mechanism is an essential component when it comes to wrapped and packaged items. The vacuum allows steam to penetrate hard-to-reach areas where ambient air would otherwise remain. The steam can permeate the packaging to achieve sterilization. A third design of steam sterilization is steam flush pressure pulse (SFPP). SFPP refers to a cycle of steam flushes and pressure pulses while the chamber remains above atmospheric pressure, resulting in a shorter sterilization period. This process is monitored at 270°F or 275°F for three or four minutes. SFPP is not to be confused with "flash" sterilization. This type of steam sterilizer can be practical and reliable for dental offices. Autoclaves' short time and ease of use benefit a busy practice.
Immediate-Use Steam Sterilization (IUSS), or "flash" sterilization, is a variation of a steam sterilization cycle where patient-care items sterilize using minimal cycle parameters. This process is used when instruments are transferred to the area of use with aseptic care and will not be stored before use. Aseptic refers to the technique in which sterilized products are handled with extreme care to keep the object from becoming contaminated while handling. Flash-sterilized instruments are often unwrapped and transported to the place of use immediately following the sterilization cycle. Flash sterilization is not recommended as a replacement for purchasing additional instruments or for convenience. Dental instruments should be wrapped and packaged according to the manufacturer's instructions for use (IFU) and CDC Guidelines.
Alternatively, dry-heat is another method for sterilizing dental instruments and equipment. Two types of dry-heat include static-air and forced-air. This process of using dry-heat compared to steam is more often time-consuming due to the time it takes to reach the temperature necessary for killing spores. Typical time and temperature settings are 340°F for 60 minutes, 320°F for 120 minutes, and 300°F for 150 minutes. Additionally, dry-heat sterilizers require different monitoring with spore tests that measure bacteria that are more resistant to dry-heat. Dry-heat sterilization does not effectively kill prions, which are a set of rare, progressive neurodegenerative disorders. A benefit to dry-heat sterilizers is that instruments do not get wet in the process.
Static-air sterilizers have coils located in the base of the machine that produces heat through gravity convection. As the heat rises up the sides of the chamber, it settles onto instruments creating the sterilization process. Think of this as an oven. Forced-air sterilizers have a fan that circulates the air inside the chamber. Heat kills the microorganisms on the instruments as forced air moves around the chamber. While dry-heat sterilization is nontoxic and easy on the environment, the process of reaching sterilization is lengthy.
The least common type of sterilizer, chemical vapor sterilizers, uses harsh chemical vapors to reach microbicidal activity. Alcohol, formaldehyde, ketone, acetone, and water mix to create a vapor for sterilization. As with other methods, time, pressure, and temperature are important parameters to achieve microbicidal activity. The vapor should reach 270°F with a pressure of 25 p.s.i. for a minimum of 20 minutes. Instruments must be completely dry before the process, and manufacturer-approved packaging must be used in order for the vapors to penetrate properly into the packs.
Concerns about the chemicals used in the sterilizer pertain to the exposure to operators and the environment. Vapors can remain in the chamber after a cycle posing a risk to staff. Formaldehyde monitoring badges are available from suppliers to warn against hazardous exposures. A 37% solution of formaldehyde gas in water called formalin can be toxic and carcinogenic. Another downfall of these machines is the disposal of hazardous waste. Special considerations must be taken according to state and local authority guidelines. The Occupational Safety and Health Administration (OSHA) has a specific standard for formaldehyde exposures – 29 CFR 1910.1048.
Glass bead "sterilization" is found in several countries worldwide. The machines are comprised of small beads that heat rapidly inside a well to sanitize small devices, such as endodontic files, chairside. Specifications for use indicate that instruments become sterile after 15 seconds, but according to a study conducted in 2008, the bead sterilizer time must be at least 60 seconds to kill spore-forming bacteria. A report filed with the U.S. Food & Drug Administration (FDA) in 2021 revealed that a laryngeal mirror was inserted into a patient's mouth after placement in a bead sterilizer causing significant burns. Since bead sterilizers cannot be properly monitored with temperature and time, the FDA has not cleared them as a sterilizer, and their use should be discontinued. According to the FDA, bead "sterilizers" are not sterilizers at all and should not be used to sterilize patient care items.
Sterilizers used in dental offices are often table-top machines that have the potential to take up little space. Considering the size and workflow of your practice, it is necessary to examine which sterilizer or sterilizers will be best for the needs of your dental practice. Steam autoclaves are effective, reliable, environmentally safe, and considerably faster than dry-heat. Following the manufacturer's instructions for a steam sterilizer can help with issues such as wet packs and rust. Instruments should be dry before packaging in a peel pouch or paper wrap. This helps ensure that instruments are dry following a complete sterilization cycle in a steam autoclave. Barrier milk is a product that coats instruments to help with corrosion and rust, reducing friction. The lubricant is applied to hinged instruments and should not be rinsed off before packaging for sterilization. Dry-heat sterilizers are often not practical because the long process to achieve heat penetration is very time-consuming. Some plastics cannot withstand the high heat required for sterility. While this type of sterilizer is not environmentally harmful, they are not common to see in dental offices. Chemical vapor sterilizers pose a risk of possible exposure to employees, albeit in a controlled chamber. If solutions are not handled correctly, leaks or spills could occur. Considering the effects it could pose on the environment if not properly disposed of, chemical/vapor sterilizers are also not practical for dentistry.
In short, the CDC recommends sterilizing steam on all critical and semi-critical items to prevent pathogen transmission. Mechanical, chemical, and biological monitors have effectively determined that steam autoclaves are practical, safe, and effective for dental practices and should be the primary source of sterilization.
Whether purchasing additional instruments is necessary or adding a sterilizer into service, you should decide which is more profitable for the business. Mark Tholen, DDS, published an article on this very subject. He discusses that profitability and productivity increase with proper cleaning and sterilization equipment. Dr. Tholen explains the benefits of cassettes, like Hu-Friedy's Instrument Management System™, that will cut down on the time and labor of sorting and cleaning individual instruments. Additionally, sterilization capacity is a significant factor in reducing labor costs and increasing office capabilities. He recommends an office should have at least two different types of steam sterilizers of different sizes and cycle types.
Several different types of sterilizers are available for dental practices. Thinking about how many patients you see a day, how many staff work each day, and how much sterilization needs to be done determines what type and how many sterilizers you need. Steam autoclaves are the standard when it comes to efficiency, practicality, and safety.
Canham, L. (2011, March 21). Sterilization of instruments: Successes and pitfalls Part 1 -- sterilizers and sterilization packaging. Dentistry IQ. Retrieved May 24, 2023, from https://www.dentistryiq.com/dental-assisting/article/16356647/sterilization-of-instruments-successes-and-pitfalls-part-1-sterilizers-and-sterilization-packaging
Condrin, A. K. (2014, August 1). Disinfection and Sterilization in Dentistry. TDA Perks Program. Retrieved May 24, 2023, from https://tdaperks.com/disinfectionsterilization/
Gupta, A. (n.d.). Sterilization 101: How Does a Laboratory Autoclave Work? Consolidated Sterilizer Systems. Retrieved May 24, 2023, from https://consteril.com/how-does-a-laboratory-autoclave-work/#:~:text=The%20terms%20steam%20sterilizer%20and,in%20hospitals%20or%20pharmaceutical%20settings.
Food & Drug Administration (2021). Premier Dental Products Company Deluxe Model B Hot Bead Sterilizer Mirror Warmer (ReportNo.2511556-2021). Department of Health & Human Services.
Kohn WG, Collins AS, Cleveland JL, Harte JA, Eklund KL, Malvitz DM; Centers for Disease Control and Prevention (CDC). Guidelines for infection control in dental health-care settings—2003. MMWR Recomm Rep. 2003 Dec 19;52(RR-17):1-61.
Palenik, C. J. (2008, May 1). Instrument sterilization: Processing. Dental Economics. Retrieved May 25, 2023, from https://www.dentaleconomics.com/science-tech/article/16387417/instrument-sterilization-processing
Tholen, M., DDS (2009, October 1). Increase production and decrease expenses in sterilization. Dental Economics. Retrieved May 26, 2023, from https://www.dentaleconomics.com/practice/overhead-and-profitability/article/16389257/increase-production-and-decrease-expenses-in-sterilization
[Tomy]. (2021, May 20). Types of Autoclaves (Gravity vs. Vacuum Autoclaves) and Their Advantages [Video]. YouTube. https://www.youtube.com/watch?v=aC1-nlIeUys
(2016, September 18). Steam Sterilization: Guideline for Disinfection and Sterilization in Healthcare Facilities 2008. Centers for Disease Control. Retrieved May 24, 2023, from https://www.cdc.gov/infectioncontrol/guidelines/disinfection/sterilization/steam.html
(2017, May 12). Instrument Reprocessing - Immediate Use Steam Sterilization (IUSS) Print What are important considerations associated with Immediate-Use Steam Sterilization? The Joint Commission. Retrieved May 24, 2023, from https://www.jointcommission.org/standards/standard-faqs/ambulatory/infection-prevention-and-control-ic/000002122/#:~:text=Immediate%2DUse%20Steam%20Sterilization%20(IUSS,transfer%20onto%20the%20sterile%20field%22.
(2018, October 22). Guide to Steam Sterilization Cycles - Steam Flush Pressure Pulse. Steris. Retrieved May 24, 2023, from https://www.steris.com/healthcare/knowledge-center/sterile-processing/guide-to-steam-sterilization-cycles-steam-flush-pressure-pulse
(n.d.). DRY HEAT STERILIZATION: STATIC-AIR VS. FORCED-AIR. Despatch. https://www.despatch.com/blog/dry-heat-sterilization-static-air-vs-forced-air/#:~:text=Static%2Dair%20sterilizers%20work%20on,on%20whatever%20you%20are%20sterilizing.
Written by Deanna Otts-Whitfield RDH, BSDH, MSHQS, CDIPC
Deanna Otts-Whitfield is a clinical consultant with Dental Compliance Specialists. She works with clients to help them successfully adhere to regulatory agencies. After high school, she served four years in the United States Marine Corps. She obtained her bachelor's degree in 2009 and executive master's in 2020. Just two years later, she decided to hang up her loupes. Her 14 years as a clinical dental hygienist have proved to be vital in the compliance sector. With experience in private and public health settings, her knowledge extends beyond the operatory. She has a passion for learning and helping people. You can contact her at Deanna@DentalCompliance.com.
Dental Compliance Specialists helps make dental offices safer for patients, dentists and their employees. We help our clients develop and maintain their compliance programs including OSHA/Infection Control, HIPAA, DEA regulations and prescribing practices, Radiation Safety, OIG/Medicaid Compliance, Record Auditing, and more by providing actionable systems, easy-to-use tools, robust training, and accountability. Most of our clients have never been in trouble and want to keep it that way. Sometimes, though, dentists call when they are in trouble. In either case, we are there to make a meaningful difference. If you need help call us at 817-755-0035.