In the first installment of this article –published in number 235 of GACETA DENTAL– we address the characteristics of cleaning, disinfection and sterilization methods.In this delivery we continue with the cleaning, disinfection and sterilization of the clinic's material.The disinfection and sterilization of dental instruments is of the utmost importance due to the possibility of transmitting infectious diseases.Both the American Dental Association (ADA) and the Center for Control and Prevention of Infectious Diseases (CDC), the Occupational Health Safety Administration (OSHA) and the Sanitary Regulation Law of the Community of Madrid (LOSCAM) have established a series of measures for the prevention and control of infections in Dentistry, which aim to reduce the risks of cross-transmission that exist in the dental clinic (1-5).Instrument cleaning and disinfection (7, 17)They precede the sterilization processes, since it is necessary to eliminate both the waste and the contamination of the instruments.This is achieved either by washing with a surfactant (detergent and water) or by an automated process (ultrasound or a disinfectant washer with cleaning agent) using chemicals.If visible residues, both organic and inorganic, are not removed, they can interfere with microbial inactivation and may compromise the disinfection or sterilization process.After cleaning, instruments should be rinsed with water to remove chemicals or detergent residue.Cleaning: removal of residues –such as blood, protein substances, microorganisms and other debris–, which is generally carried out with water and detergent or enzymatic cleaner, from the surfaces, grooves, joints of instruments, devices and equipment, either by a manual or mechanical process, which prepares items for safe handling and/or further decontamination.Disinfection: thermal or chemical destruction of pathogens and other types of microorganisms.Disinfection is less lethal than sterilization as it does not destroy all microbial forms (eg bacterial spores).We must place the instruments in a resistant container and soak them with a disinfectant detergent or an enzymatic cleaner, to prevent the patient's material from drying out and to make cleaning easier and in less time.A high-level disinfectant or sterilizing chemical (eg, glutaraldehyde) may be used.Dental instruments can be cleaned manually or mechanically.Automated mechanical cleaning is preferred over manual cleaning because it reduces the risk of blood exposure and skin injury from sharps penetration.Cleaning dental instruments manually is the least effective method and the highest risk for the operator.If used, the instruments must be completely immersed in a specific cleaning container with warm water and detergent.The water for manual cleaning must be lukewarm, since hot water favors the coagulation of proteins and cold water solidifies the lipids present in the contaminants.This would make cleaning difficult, so they should not be used.A slightly alkaline, good rinsing and non-abrasive liquid detergent should be used, which is much more effective than a neutral detergent in removing blood and fatty substances.Common household detergents should not be used, due to difficulties in rinsing.This can interfere with the sterilization/disinfection process, as well as increasing the risk of cuts and penetrating injuries from sharp instruments to the operator.• Use of a long-handled brush to remove debris and avoid injuries caused by sharp instruments.• Cleaning gloves should be used to avoid direct contact with instruments and other contaminated devices.• Use of mask, protective glasses and adequate clothing.Finally, the material should be inspected to ensure that all surfaces of all instruments are clean.Cleaning brushes should be washed, rinsed and stored dry.Mechanical cleaning of instruments can be carried out in instrument washers or ultrasonic cleaners.Instrument washers are more efficient at pre-sterilization cleaning than ultrasonic cleaners.They should not be used as a substitute for sterilization.Washers must be well maintained and cleaned regularly to prevent biofilm formation, which could contaminate instruments being processed.Items must be free of dirt before being placed in the ultrasonic cleaner.• Lids, tank, gaskets and filters must be cleaned daily.• The cleaning fluid should be changed a minimum of twice a day (or when it appears heavily contaminated).• The lid must be closed during operation (to avoid dispersion of aerosols).• Instruments must be completely submerged in the liquid, and no part of the operator's fingers, or hands, must be submerged in the liquid during operation.At the end of each day, the ultrasonic cleaner tank must be emptied, cleaned and allowed to dry.–Alcohol 70º for metallic surfaces.Low disinfection level: removes most bacteria, some fungi and some viruses (HBV, HCV and HIV).It is not effective against Mycobacterium tuberculosis bovis variety, nor against bacterial spores.Intermediate level of disinfection (tuberculocidal): it is effective for bacteria, including Mycobacterium tuberculosis bovis variety, viruses, and fungi;excluding spores.High level of disinfection (tuberculocidal and sporicidal): eliminates all microorganisms and some bacterial spores, but not necessarily all.After cleaning the instruments and other dental supplies, they must be inspected, dried and packaged.Hinged instruments are processed and unlocked.An internal chemical indicator must be placed in each package;if this is not visible, an external chemical indicator will be placed.Packaging materials must be designed for the type of sterilization process being used.Steam tolerant dental instruments are generally sterilized by:1) Pressure steam (autoclave).2) Unsaturated chemical vapor.According to the CDC, all sterilization methods must be performed using FDA-approved medical sterilization equipment.The sterilization time, temperatures and other operating parameters must be those recommended by the manufacturer, as well as the instructions for the correct use of chemical and biological indicators.Instrument kits must be allowed to dry inside the sterilizer chamber before removal and handling.The packages should not be touched until they are cool and dry, because hot packages absorb moisture (17).Sterilization and disinfection of dental instruments (1)Sterilization: It is the process by which all forms of existing microorganisms are destroyed, including spores, a fundamental component in maintaining a clean and safe environment for the provision of oral health services.Prior to each patient's use of reusable material, surgical and critical medical devices and instruments that normally enter sterile tissues or the vascular system or those through which body fluid flows should be sterilized.• Disinfection, cleaning, packaging and placement of instruments.– 121º-124ºC: rotary, plastics.– 134º-138ºC: metallic instruments.Autoclave: steam sterilization (Table 4)Pressurized steam is the preferred method of sterilizing dental instruments because of its efficiency and simplicity, as long as it is not sensitive to heat, pressure, or moisture.Unsaturated chemical steamIt consists of heating a chemical solution mainly of alcohol with 0.23% formaldehyde in a closed place with a pressurized chamber.Unsaturated chemical steam on carbon steel instruments (eg dental burs) causes less corrosion than steam sterilization, due to the low level of water present during the cycle.Instruments must be dry prior to sterilization.State and local authorities should be consulted for hazardous waste disposal requirements for sanitizing solution.Dry heat sterilizationDry heat is used to sterilize materials that could be damaged by moist heat (eg, burs and some orthodontic instruments).Although dry heat has the advantage of low operating cost and non-corrosiveness, it is a time-consuming process and the high temperatures required are not suitable for certain devices.Dry heat sterilizers used in dentistry include static air and forced air types.• The static air type, commonly called an oven-type sterilizer, has heating coils in the bottom or sides of the unit causing it to heat the air inside the chamber.• The forced air type is also known as a rapid heat transfer sterilizer.Hot air is distributed throughout the chamber at high speed, allowing faster transfer of energy from the air to the instruments, reducing the time required for sterilization.Other disused sterilization mechanisms• Fast sterilization ("flash" sterilization)It is a method for the sterilization of unpackaged instruments and for immediate use.This cycle operates at a higher temperature for a shorter period of time than the normal sterilization cycle.The CDC recommends that flash sterilization not be used routinely in the dental office to sterilize instruments.– No packaging material or containers should be used in flash sterilization cycles, except if the sterilizer and packaging are designed for this use.– Material sterilized using the “flash” program must be used immediately after sterilization.– Material that must be packaged, sterilized and stored before use should not be sterilized using the “flash” program.When using this method you must ensure that:– The cleaning of the objects before introducing them in the container or in the tray.– Avoid exogenous contamination of objects during their transfer from the sterilizer to the point of use.– Monitor the operation of the sterilizer with physical, chemical and biological indicators.•Immersion in sterilizing liquidsCritical and semi-critical heat-sensitive instruments and other devices can be sterilized by immersion in chemical germicidal liquids registered by the FDA as sterilants.When using a liquid chemical germicide for sterilization, certain post-sterilization procedures are essential.Devices must be:1) Treated with sterile water after removal of toxic or irritant residues.2) Handled with sterile gloves and dried with sterile towels.3) Delivered at the point of use, aseptically.• Material sterilized by immersion in liquids should not be stored before use;Instruments should not be considered sterile and should be sterilized again just prior to use.• The sterilization process with liquid chemical sterilants cannot be verified with biological indicators.• Liquid chemical sterilants may require approximately 12 hours of complete immersion.• Little used to sterilize instruments.These chemical products are mainly used in high-level disinfection, reducing the immersion times (12-90 minutes) used to achieve a high level of disinfection of semi-critical instruments.These chemicals are powerful as they are sporicides (glutaraldehyde, peracetic acid and hydrogen peroxide).They are very toxic, and strict compliance with the manufacturer's instructions (in relation to dilution, immersion time, temperature and safety) is essential.These chemicals should not be used for applications other than those outlined in the manufacturer's instructions (misapplications include use as an environmental surface disinfectant).Compliance with appropriate precautions (closed containers to limit release of vapors, chemical resistant gloves and aprons, goggles and face shields) is necessary.Glutaraldehyde-based products can cause dermatological changes, eye irritation, respiratory and skin conditions.Cases of sensitization have been reported.Medical gloves are not an effective barrier against glutaraldehyde due to their lack of chemical resistance.• Sterilization at low temperature with ethylene oxideIt has been widely used in large health centers.However, for the dental clinic, due to the sterilization times of 10 to 48 hours and the difficulty of gas penetration in the rotaries, its use is not recommended.• Sterilization of high and low speed handpiecesSemi-critical dental devices that come into contact with the mucous membranes that are connected to the dental unit's water and air lines – such as high and low speed handpieces, prophylaxis ultrasound, air and water syringes – can be contaminated.Therefore, the following precautions will be taken in these devices:• Run the flush of water, air, or a combination, a minimum of 20-30 seconds after each patient.This procedure is intended to expel debris that might have entered the turbine.• Heat methods can sterilize handpieces and other intraoral devices connected to water or air lines.121-124ºC rotating in the autoclave.• Neither surface disinfection nor immersion in chemical germicides is an acceptable method.• Ethylene oxide cannot adequately sterilize the internal components of handpieces.• Manufacturer's instructions for cleaning, lubrication, and sterilization must be followed closely to ensure both the effectiveness of the process and the longevity of the handpiece.The Spaulding classification is a traditional approach, it has been used to determine the level of disinfection or sterilization required for reusable medical devices, based on the degree of risk for the transmission of infections described in Table 5 (7).Barrier or protection elements (6, 8, 11)Among the standard precautionary measures is the use of barrier elements by health personnel, their compliance minimizes the risk of infection transmission and they are essential for the care and treatment of patients, regardless of whether or not they are diagnosed with a contagious disease , due to frequent exposure to blood, saliva or other body fluids (Table 6).Possible routes of transmission (6, 9)Dental practice often involves the use of sharp objects, with blood exposure, sometimes with limited access and poor visibility, which makes us follow protocols to reduce the risk of suffering an injury, and thus reduce the possible routes of transmission that are shown in table 7.Rules of action to avoid possible routes of transmission (8,14)• Avoid passing sharp objects to other people.• If necessary, direct the sharp tip away from our body.Keep fingers out of the way.• Needles should not be recapped (one-handed technique).• Use of resistant containers for sharp objects no more than three quarters.Pathogenic microorganisms that can be transmitted in the dental clinic (6, 9, 16)There is evidence that health personnel in the dental clinic are exposed to communicable diseases, so it is necessary to follow the established protocols (Table 8) (JADA, 1988; 117: 447-83).Sterilization control (7, 9, 11, 13, 16)It is essential, prior to any method that we choose, to carry out a correct cleaning of the instruments to avoid residues that protect microorganisms and interfere with the effectiveness of the sterilizing agent.However, we must monitor the correct compliance with the following factors:• Insufficient time for the bactericidal process.• Excessive or incorrect packaging material to perform sterilization.• Incorrect instrument separation even without overload.It is necessary to have indicators to confirm that our method has been carried out correctly.The authors agree that the best control for sterilization is by performing a combination of these 3 methods described in Table 9 (9, 10,13).1. Autonomous Community of Madrid: Prevention and control of communicable diseases.Recommendations in Odontostomatology.2. ADA Council on Scientific Affairs and ADA Council on Dental Practice: (1996) Infection control recommendations for the dental office and the dental laboratory.JADA, vol.127, May, 672-80.3. Accepted Dental Therapeutics: (1982) Sterilization or Disinfection of Dental Instruments.39th ed, 100-14.4. Informative Brochure of the MSAS Oral Pathology Technical Group (1994): Standards for the Prevention and Control of Infectious Diseases in dental practice.5. Torres and Ehrlich: (1995) Disease Transmission and Infection Control in Modern Dental Assisting, 5th edition, Philadelphia, WB Saunders.6. 2007 Guideline for Isolation Precautions: Preventing Transmission of Infectious Agents in Healthcare Settings.7. William A. Rutala, Ph.D, David J. Weber, MD, MPH, and the Healthcare Infection Control Practices Advisory Committee (HICPAC) Hospital Epidemiology.Guideline for Disinfection and Sterilization in Healthcare Facilities, 2008.8. ADA Guidelines for infection control.Australian Dental Association Inc. 2008.9. Jennifer A. Harte Standard and Transmission-Based Precautions: An Update for Dentistry JADA 2010;141;572-581.10. American Dental Association JADA, Vol. 135, January 2004.11. Palanca Sanchéz I, Ortiz Valdepeñas J, Elola Somoza J, Bernal Sobrino JL, Paniagua Caparrós JL.Central sterilization unit: standards and recommendations.Madrid: Ministry of Health, Social Policy and Equality;2011.12. Jennifer A. Harte, DDS, MS;MSD Characteristics of infection control programs in US Air Force dental clinics.JADA, Vol. 136 July 2005.13. Guideline for Hand Hygiene in Health-Care Settings Recommendations of the Healthcare Infection Control Practices Advisory Committee and the HICPAC/SHEA/APIC/IDSA.October 25, 2002 / Vol. 51 / No. RR-16.14. CJ Palenik, FJT Burke, WA Coulter, SW Cheung.Improving and monitoring autoclave performance in dental practice British Dental journal, volume 187, no.11, December 11 1999.15. Dale N. Gerding, Carlene A. Muto, Robert C. Owens, Jr. Measures to Control and Prevent Clostridium difficile Infection.Measures to Control and Prevent CDI • CID 2008: 46.16. John A. Molinari, Ph.D.Infection control its evolution to the current standard precautions JADA, Vol. 134, May 2003.17. Centers for Disease Control and Prevention.Guidelines for Infection Control in Dental Health-Care Settings, 2003. MMWR 2003;52 (No. RR-17): [including page numbers].18. Community of Madrid.Oral health in the elderly.Prevention and care for comprehensive care.Health promotion service.Institute of Public Health.Ministry of Health.Dra. Kenia Selva, Dentist from the European University of MadridDr. Alicia Martín Cerrado, Dentist, Doctor from the UCM.Master in Oral Implantology by the UEM.Professor of Integrated Dentistry for Adults UEM.Dr. Juan Carrión Bolaños, Medical Specialist in Stomatology.Doctor in medicine.Professor of the Department of Dentistry UEM.Dr. Margarita Gómez Sánchez, Dentist, Doctor from the UCM.Expert in Aesthetics by the URJC.Professor of Legal and Forensic at UEM.Dra. Ana Suárez García, Dentist, Doctor from the UCM.Master's degree in oral implantology from the UCM.Professor of Restorative Dentistry I and II.Login to leave a commentThis website uses its own and third-party cookies to improve the user experience, perform user navigation analysis, show advertising related to your preferences and improve our services.If you continue browsing, we consider that you reject the use of cookies, and navigation errors or display problems of certain contents may occur.For more information, consult our cookies policy in advance.