cep Cleaning of Dental Instruments Scottish Dental Clinical Effectiveness Programme
Scottish Dental Clinical Effectiveness Programme SDcep The Scottish Dental Clinical Effectiveness Programme (SDCEP) is an initiative of the National Dental Advisory Committee (NDAC) and is supported by the Scottish Executive and NHS Education for Scotland. The Programme aims to provide user-friendly, evidence-based guidance for the dental profession in Scotland. Cleaning of Dental Instruments Dental Clinical Guidance SDCEP guidance is designed to help the dental team provide improved care for patients by bringing together, in a structured manner, the best available information that is relevant to priority areas in dentistry, and presenting this information in a form that can be interpreted easily and implemented. ‘Cleaning of Dental Instruments’ is the first of the SDCEP series ‘Decontamination Into Practice’, which aims to help the evolution towards compliance with relevant statutory and mandatory requirements and standards. ‘Cleaning of Dental Instruments’ provides advice on all aspects of cleaning, including organising the decontamination area, cleaning methods and testing of equipment. Scottish Dental Clinical Effectiveness Programme Dundee Dental Education Centre, Frankland Building, Small’s Wynd, Dundee DD1 4HN Email [email protected] Tel 01382 425751 / 425771 Website www.scottishdental.org/cep March 2007 Scottish Dental Clinical Effectiveness Programme SDcep The Scottish Dental Clinical Effectiveness Programme (SDCEP) is an initiative of the National Dental Advisory Committee (NDAC) and is supported by the Scottish Executive and NHS Education for Scotland. The Programme aims to provide user-friendly, evidence-based guidance for the dental profession in Scotland. SDCEP guidance is designed to help the dental team provide improved care for patients by bringing together, in a structured manner, the best available information that is relevant to priority areas in dentistry, and presenting this information in a form that can be interpreted easily and implemented. ‘Supporting the dental team to provide quality patient care’ Scottish Dental Clinical Effectiveness Programme SDcep Cleaning of Dental Instruments Dental Clinical Guidance March 2007 © Scottish Dental Clinical Effectiveness Programme ISBN 978 1 905829 03 3 First published March 2007 Scottish Dental Clinical Effectiveness Programme Dundee Dental Education Centre, Frankland Building, Small’s Wynd, Dundee DD1 4HN Email [email protected] Tel 01382 425751 / 425771 Website www.scottishdental.org/cep Cleaning of Dental Instruments Cleaning of Dental Instruments 1 Introduction 1 2 Organising Cleaning Within the Decontamination Area 2 2.1 2.2 2.2.1 2.2.2 2.3 2.4 2.4.1 2 2 3 4 4 4 5 3 Pre-cleaning Procedure 3.1 3.2 3.3 3.4 3.5 3.6 4 5 6 Purchasing Instruments and Training Staff Setting Up a Decontamination Area Physical Segregation Temporal Separation Ventilation Hand Hygiene Good Practice Points During Treatment Taking Instruments to the Decontamination Area Segregating Instruments Items for Disposal Re-usable Instruments Items Unsuitable for Immersion 7 7 7 8 8 10 10 Cleaning Methods 11 4.1 4.2 4.2.1 4.2.2 4.2.3 4.3 4.3.1 4.3.2 4.3.3 4.4 4.4.1 4.4.2 11 12 12 13 13 14 14 15 16 17 18 21 General Requirements for Each Cleaning Method Manual Cleaning Workflow and Facilities Cleaning Procedure Avoiding Instrument Damage Ultrasonic Cleaning Points to Consider Before Purchasing an Ultrasonic Cleaner Validating the Operating Procedure for Ultrasonic Cleaners Ultrasonic Cleaning Procedure Washer-disinfectors Points to Consider Before Purchasing a Washer-disinfector Using a Washer-disinfector Rinsing, Drying, Inspection and Care of Instruments 22 5.1 5.2 5.2.1 5.2.2 5.2.3 5.2.4 5.3 22 22 23 23 23 23 24 Rinsing and Drying of Instruments after Cleaning Inspection and Care of Instruments before Sterilizing Inspection for Cleanliness Functional Inspection Lubrication Handpiece Care Out-of-hours Use of Instruments Validation, Testing and Maintenance of Cleaning Equipment 25 6.1 6.2 6.2.1 6.2.2 6.3 6.3.1 6.3.2 25 25 25 25 27 27 28 Validation Maintenance and Testing of an Ultrasonic Cleaner Maintenance Testing Installation and Testing of a Washer-disinfector Installation Routine Testing iii Cleaning of Dental Instruments iv Cleaning of Dental Instruments 1 Introduction Decontamination of dental instruments and equipment ideally involves cleaning, thermal disinfection and sterilization and is an important branch of infection control. Effective cleaning is essential to enable disinfection and sterilization of instruments to be carried out reliably. Any organic material or adherent dental materials left on instruments can inhibit these processes. This can also cause corrosion of instruments or impair their function, and might lead to cross-infection from one patient to another. The Scottish Dental Clinical Effectiveness Programme is providing a series of guidance documents entitled ‘Decontamination Into Practice’ that addresses different aspects of instrument decontamination. This series is part of a national initiative to standardise good decontamination practice. Aimed specifically at those working in primary care dental services, ‘Cleaning of Dental Instruments’ presents practical advice on the first stage of the decontamination process: how to thoroughly clean dental instruments. This advice is based on a range of existing guidance documents and has been developed through consultation with the Health Protection Scotland (HPS) Decontamination Team, other experts and end-users. Supplementary advice that relates to the whole decontamination process is provided separately in the appendices. Decontamination-related weblinks are also included throughout the text for those who need additional information. Many of these links can be accessed via the Decontamination section of the ScottishDental website: www.scottishdental.org/decontam. In particular, the following Scottish Health Technical Memoranda (SHTM) have detailed information on how to choose, use and validate equipment for decontamination processes: • SHTM 2010 Sterilization • SHTM 2030 Washer-Disinfectors (also includes ultrasonic cleaning machines) 1 Cleaning of Dental Instruments 2 Organising Cleaning Within the Decontamination Area 2.1 Purchasing Instruments and Training Staff Before buying instruments: • check the manufacturer’s decontamination instructions to ensure that the instruments can be decontaminated with the facilities that you have available, or buy single-use instruments; • give preference to buying instruments that can be cleaned using automated methods (e.g. washer-disinfector) that you might adopt in the future. Train all staff in the basics of infection control procedures, including: • how infections are transmitted; • how to prevent transmission of infections; • what to do in the event of an accident or personal injury; • your practice policy on infection control. Ensure staff are fully vaccinated against hepatitis B. For staff involved in cleaning instruments, give practical training in all stages of the decontamination process. Record details of training in the staff training manual or each individual’s personal development file. Ensure personal protective equipment (PPE) (i.e. gloves, facemask, eye protection, plastic disposable aprons and adequate footwear) is available and worn. This provides a protective barrier against the spread of infections through contact with blood or body fluids either directly or via splatter or aerosol spray. 2.2 Setting Up a Decontamination Area Use a dedicated decontamination area, separated from the patient treatment area, preferably in another room or rooms. • If, through lack of space, decontamination has to be carried out in a patient treatment room, minimise the risk to patients by deferring decontamination until the room is unoccupied and ensure that rigorous environmental cleaning is carried out between clinical and decontamination activities. As this takes time and will inevitably affect the frequency of patient appointments, plan to move towards a separate dedicated decontamination area as soon as possible. • When setting up new premises or planning significant modification to existing premises, consider having two rooms for decontamination that are separate from the patient treatment area(s): one for dirty activity (cleaning instruments) and one for clean activity (inspection, sterilization and wrapping instruments). This is the preferred arrangement. 2 Cleaning of Dental Instruments 2 Organising Cleaning Within the Decontamination Area Irrespective of the specific layout, a tidy working environment makes carrying out decontamination easier. Therefore, declutter your working environment. Carry out the decontamination process as a dirty-to-clean workflow that ensures dirty instruments or splashes or aerosols generated during cleaning do not come into contact with clean instruments. This is a one-way process that can be achieved by physical segregation or temporal separation. Advice on environmental cleaning is given in ‘Control of the Environment Policy and Procedure’, published by Health Protection Scotland (HPS) (available via www.scottishdental.org/decontam). 2.2.1 Physical Segregation Physical segregation means using different areas for different activities. Set up a decontamination area that preferably comprises a single run of sealed, easily cleaned worktop with the following items arranged in the order listed: • a separate hand-washing sink; • a setting-down area for dirty instruments; • a washing sink with detergent for cleaning instruments; • a setting-down area for washed instruments; • an ultrasonic cleaner, if appropriate (see Sections 4 and 6); • a rinsing sink; • a setting-down area for rinsed instruments; • an automated washer-disinfector (includes drying cycle); • a setting-down area with task lighting and magnifier for inspection of all instruments (to check instruments for visible contamination and functionality or damage, and to ensure instruments are dry); 3 Cleaning of Dental Instruments 2 Organising Cleaning Within the Decontamination Area • an area for wrapping instruments (only if a benchtop vacuum sterilizer is to be used); • a steam sterilizer; • an area for setting down and wrapping instruments sterilized in a benchtop nonvacuum (bowl and instrument) sterilizer; • clean, orderly, enclosed storage for instruments prior to use (not open shelving); • a dedicated, clean, rigid, labelled box with a lid to transport instruments to the clinical area safely and securely. 2.2.2 Temporal Separation Temporal separation means using the same area for two separate activities at different times. If, through lack of space, a work surface is used for both dirty and clean instruments, ensure that the surface is thoroughly cleaned, and if necessary disinfected, between the two activities to avoid recontamination of cleaned instruments. Regard temporal separation as a temporary arrangement and plan to increase the space for the decontamination area to enable physical segregation of decontamination activities as soon as possible. 2.3 Ventilation Within the decontamination area, ensure that air flow is maintained away from the patient area and does not carry contaminants from the dirty area to the clean area. Do not use portable fans in the decontamination area because rapid uncontrolled air circulation can spread contamination. More-detailed information on planning decontamination facilities, including basic ventilation requirements for local decontamination units, is currently under development and will be published as Scottish Hospital Planning Note 13. 2.4 Hand Hygiene The term hand hygiene covers not only hand washing, but also alternative and additional measures such as hand disinfection using alcohol rubs/gels. Hand hygiene is crucial in preventing the spread of infection. Gloves are not a substitute for hand hygiene because microorganisms flourish under gloves. Therefore, clean hands before and after using gloves. 4 Cleaning of Dental Instruments 2 Organising Cleaning Within the Decontamination Area There are three different levels of hand hygiene. The level required depends on the potential for, or actual, contamination of the hands. Carry out a risk assessment of the level required before and after different procedures. Advice on how and when to employ the three levels of hand hygiene is given in ‘Hand Hygiene Policy and Procedure’ published by HPS (available via www.scottishdental.org/decontam). A summary of the three levels is provided in Appendix 2. 2.4.1 Good Practice Points Staff Keep nails short and clean. Do not wear artificial nails or extensions or nail varnish if working in the clinical environment, including decontamination areas. Remove wrist and hand jewellery, including wrist watches, before working in the clinical environment or the decontamination area. A plain wedding band is acceptable but this must be moved or removed when performing hand hygiene to ensure the area under the ring is cleaned and dried thoroughly. Facilities and procedures Ensure that there is a separate sink for hand washing in the decontamination area and that the sink: • does not have a plug or an overflow and is fitted with a remote running trap (i.e. the U bend is not directly under the plughole); • has an electronic sensor-operated or elbow/wrist lever-operated mixer tap; • has a tap that runs into the sink basin and not straight down the drain to avoid aerosol from the drainage system splashing back onto the user. Use wall-mounted liquid handwash dispensers with disposable cartridges and ensure the nozzle is kept clean. Do not use refillable handwash containers as bacteria can multiply within many of these products and are therefore a potential source of contamination. Apply the handwash to wet hands to reduce the risk of irritation, and perform hand washing under running water. • Details of the types of products to be used for different levels of hand hygiene can be obtained from the HPS ‘Hand Hygiene Policy and Procedure’ (available via www.scottishdental.org/decontam). 5 Cleaning of Dental Instruments 2 Organising Cleaning Within the Decontamination Area Do not use bar soap. Do not use scrub or nail brushes because these can cause abrasion of the skin, and can be a source of infection. Use paper hand-towels and foot-operated or sensor-operated waste bins. Ensure your paper towels and drying technique do not damage the skin. Use a hand cream following hand washing at the end of a session to counteract dryness but do not use hand cream under gloves because this can encourage growth of microorganisms. Alcohol-based skin disinfectant hand rubs/gels formulated for use without water can be used on visibly clean hands instead of hand washing between patients during surgery sessions. • Follow local infection control guidance or manufacturers’ instructions on the maximum number of applications of alcohol hand rubs/gels that can be used on physically clean hands before hand washing is required. Be aware that build-up of product on the hands occurs with repeated application. Do not use alcohol-impregnated wipes as a substitute for hand rubs/gels because this is not effective in hand decontamination. Moving from dirty to clean areas When you shift from working in a designated dirty area to a clean area change your gloves and plastic apron. Wash your hands or use alcohol rub/gel on visibly clean hands when you change gloves. Ensure your local infection control policy specifies when PPE is to be worn and changed. 6 Cleaning of Dental Instruments 3 Pre-cleaning Procedure Review manufacturers’ instructions prior to purchase of instruments to ensure that all devices can be appropriately decontaminated. Failure to comply with manufacturers’ instructions can affect product guarantees and warranties. Train staff in how to prepare properly for decontamination of the range of devices used in your practice, including transporting contaminated instruments, disposing of single-use items correctly, dismantling instruments when appropriate and selecting the most appropriate cleaning method for each instrument (see below and Section 4). Remember to include new instruments in staff training and keep staff training records up to date. Draw up and use a written waste disposal policy. For further information refer to Scottish Executive Health Department Letter 2006 PCA(D)05 and Health Facilities Scotland (HFS) guidance on healthcare waste, available via www.scottishdental.org/decontam. 3.1 During Treatment Keep your standard kits to a minimum. Do not put out instruments you do not need. Regard all instruments set out for each patient as contaminated after the treatment whether or not they have been used. When working with substances that can harden on instruments (i.e. calculus during scaling or cements), wipe re-usable instruments immediately with a non-linting swab. • To avoid risk of sharps injuries it is the operator’s responsibility to ensure that residues are removed from sharp hand instruments used in the patient’s mouth, such as scalers. 3.2 Taking Instruments to the Decontamination Area Transport instruments for decontamination as soon as possible after use to the decontamination area. Use a rigid, durable, leak-proof container that has a tight-fitting lid and is easy to clean and disinfect to transport dirty instruments, and ensure it is clearly labelled as containing contaminated instruments. • It is good practice to place used instruments in this type of container even if decontamination is to be carried out in the same room. This reduces the risk of inadvertent reuse of contaminated instruments. 7 Cleaning of Dental Instruments 3 Pre-cleaning Procedure • Consider using different coloured containers to transport clean and dirty instruments. Ideally, clean containers in a washer-disinfector (WD). If this is not possible, clean containers with a fresh detergent solution, rinse and dry. Do not use bleach or hypochlorite solution because residues might damage the instruments. Further advice on transferring instruments is provided within Health Protection Scotland (HPS) local decontamination unit (LDU) guidance (available via www.scottishdental.org/decontam). 3.3 Segregating Instruments A used dental kit contains a wide variety of instruments and contaminated material. Prior to cleaning, segregate re-usable instruments to be cleaned from items for disposal. 3.4 Items for Disposal Shown below is the symbol that identifies single-use items. This label identifies the device as disposable and not intended to be reprocessed for use on the same or another patient. This will appear on packaging but might not be present on individual items. 8 Cleaning of Dental Instruments 3 Pre-cleaning Procedure Always check packaging for the single-use symbol before use and note that it might be difficult to see, as indicated in the photographs. Use single-use instruments only on an individual patient during a single procedure and then discard. The re-use of a single-use device has legal implications. Anyone who reprocesses or re-uses a device intended for use on a single occasion bears full responsibility for its safety and effectiveness. New regulations for clinical waste disposal came into force on 1 February 2007 and new guidance has been published by Health Facilities Scotland (HFS). All clinical waste (renamed healthcare waste) is now categorised as special waste and an additional colour-coded stream (Red) has been introduced for individual potentially toxic products (e.g. dental radiography chemicals, amalgam and amalgamfilled teeth) that require specialized disposal. These new regulations require changes to the labelling and paperwork associated with clinical waste. Ensure that appropriate waste containers are available for all types of waste (i.e. paper, plastic or special waste, including sharps). • Assemble all colour-coded waste-disposal containers correctly before use and ensure the lids are firmly clicked into place. A large number of sharps injuries are caused by containers separating when in use. • Check with your local waste contractor to ensure that all your colour-coded waste containers and labels comply with the latest HFS guidance. Dispose of single-use items according to their category (as outlined in your waste disposal policy). • Identify and dispose of single-use sharps, matrix bands, used and partly used local anaesthetic cartridges and extracted teeth without amalgam in Yellow Stream wastedisposal containers (formerly known as sharps bins) kept close to the point of use. • Dispose of amalgam into a designated Red Stream waste-disposal container that is clearly labelled for amalgam waste. • Dispose of extracted teeth containing amalgam into a separate Red Stream container that is clearly labelled for extracted teeth with amalgam. • Do not fill colour-coded waste-disposal containers above the specified level. 9 Cleaning of Dental Instruments 3 Pre-cleaning Procedure Recent changes to waste disposal are provided in ‘Interim SHTN 3 Guidance’, published in February 2007 by HFS (available via www.scottishdental.org/decontam). Note that a revised and updated edition of NHSScotland waste guidance Scottish Hospital Technical Note 3 (SHTN 3) is due to be published in 2007. For further information refer to local NHS board dental waste guidance. 3.5 Re-usable Instruments Separate re-usable instruments, according to manufacturers’ instructions, into those that will require manual cleaning and those that can withstand either ultrasonic cleaning or processing in a WD. Some instruments require to be dismantled for cleaning. Follow manufacturers’ instructions. After these steps, select a cleaning method that is suitable and available (see Section 4). 3.6 Items Unsuitable for Immersion Identify items that cannot be immersed in aqueous solution (e.g. electrical and electronic equipment) and clean them in accordance with manufacturers’ instructions. • If recommendations include wiping with a detergent solution, use a clean non-linting cloth and the recommended detergent solution to wipe the instrument. Follow by wiping with a clean, damp non-linting cloth to remove residues. Dry thoroughly using a clean non-linting cloth. • If disinfection with alcohol is advised, first clean as above then wipe with alcoholimpregnated wipes. 10 Cleaning of Dental Instruments 4 Cleaning Methods Three methods of cleaning re-usable dental instruments are currently available: • manual cleaning; • ultrasonic cleaning; • cleaning using a washer-disinfector (WD). The use of a WD is the preferred method of cleaning as it includes a thermal disinfection stage that renders instruments safe for handling and inspection and is an automated process that can be validated. However, more than one cleaning method will need to be employed in practice. 4.1 General Requirements for Each Cleaning Method Selecting a method of cleaning: Refer to manufacturers’ instructions for instruments, equipment, cleaning equipment and cleaning solutions to ensure that instruments can be cleaned using a method available in your practice. Maintain a list of instruments to be cleaned by each method. Staff training: Train all practice staff involved in cleaning dental instruments so that they: • understand the key principles and importance of effective cleaning; • are able to use all cleaning methods and decontamination equipment in your practice properly and safely; • can perform daily testing and maintenance of the equipment and maintain good records (see Section 6 for details). Validation: Validation is the means by which an entire process is documented, tested and able to be repeated. Ensure ultrasonic and WD cleaning procedures used in your practice are validated. This is to demonstrate that all instruments and equipment cleaned by these methods are reliably and consistently cleaned using predetermined and reproducible conditions (see Section 6 for details). Hepatitis B vaccination: Ensure staff are fully vaccinated against hepatitis B. Personal protective equipment: Wear appropriate personal protective equipment (PPE) when cleaning instruments: that is, household gloves, facemasks, eye protection, plastic disposable aprons and adequate footwear. Include this information in the practice’s COSHH assessment of blood, saliva and other biological materials. Wash household gloves with detergent and hot water and dry after each use to remove visible soil. Replace these gloves weekly or more frequently if worn or torn or if there is any difficulty in removing soil. 11 Cleaning of Dental Instruments 4 Cleaning Methods 4.2 Manual Cleaning In principle, manual cleaning is the simplest method to set up but it cannot be validated because it is difficult to ensure that it is carried out effectively on each occasion. Compared with other cleaning methods, manual cleaning presents a greater risk of sharps injury to staff. However, despite the limitations of manual cleaning, it is important for each practice to have the facilities, documented procedures and trained staff to carry out manual cleaning as a backup for when other methods are not available or are not appropriate. This method must have systems in place to avoid recontamination of clean instruments. Put in place an effective system for manual cleaning, as outlined below, and ensure all staff follow an agreed, written procedure. Use manual cleaning only when it is required by the instrument manufacturer’s instructions or if other methods are not available. Consider routinely using an automated method (e.g. a WD). Aim to phase in instruments that can be cleaned in a WD. 4.2.1 Workflow and Facilities Maintain a dirty-to-clean workflow throughout the cleaning procedure. Preferably, use two sinks: one for manual cleaning and one for rinsing. • If there is space for only one sink, rinse using a clean plastic basin alongside the sink. However, this must be regarded as a temporary measure until decontamination facilities are upgraded to include two sinks. Preferably, use separate spaces for setting down dirty and clean instruments. • If lack of space means that a setting-down space has to be used for both dirty and clean instruments at different times during the decontamination process, thoroughly clean the surface between stages with a water–detergent solution to minimise the risks of cross-contamination. Always use detergents specifically formulated for manual cleaning of instruments. NB: do not use chlorhexidine handscrub (e.g. Hibiscrub), washing-up liquid, cleaning creams or soap. Chlorhexidine in particular makes proteins stick to steel. Refer to Appendix 3 for examples of suitable cleaning products. Advice on surface cleaning is given in ‘Control of the Environment Policy and Procedure’ published by Health Protection Scotland (HPS) (available via www.scottishdental.org/decontam). 12 Cleaning of Dental Instruments 4 Cleaning Methods 4.2.2 Cleaning Procedure Measure the volume of water and detergent to achieve the exact concentration specified by the detergent manufacturer. A line painted on the sink is useful to indicate the required volume of water. Using a thermometer, monitor the temperature of the water throughout the cleaning procedure to ensure the temperature is maintained within the range recommended by the detergent manufacturer. Where manufacturers’ instructions permit, fully submerge items to be cleaned in the detergent solution. Scrub instruments using long-handled brushes with soft plastic bristles. To minimise aerosol risk, do not scrub under running water. Following cleaning, drain the water, avoiding splashing. If the water is heavily soiled, repeat the cleaning procedure. Wash brushes with detergent and hot water after each use to remove visible soil and store dry and head up. Replace brushes at least weekly or more frequently if worn or if soil cannot be removed (as shown). 4.2.3 Avoiding Instrument Damage Most dental instruments are made of high-quality materials designed to minimise corrosion if reprocessed correctly. The corrosion resistance is based on their alloy composition and structure, which forms a protective passivation layer on the surface. The ability of the instruments to resist corrosion depends on the quality and thickness of this layer. It is important to avoid damage to the passivation layer during cleaning. Avoid the use of wire brushes as this can compromise the passivation layer and increase the chance of breakage. Remove from use any instruments that have rust spots. On no account use wire brushes to remove rust spots. Do not use wire pot scourers to clean instruments because these will damage the surface of instruments. After manual cleaning, rinse, dry and inspect instruments for cleanliness and, where possible, check functionality as described in Section 5, before sterilization. 13 Cleaning of Dental Instruments 4 Cleaning Methods 4.3 Ultrasonic Cleaning Ultrasonic cleaning in a fully functioning machine enhances removal of debris, thereby reducing the need for scrubbing instruments. Thus, although a WD is preferred and should be incorporated into new plans or upgrades (see Section 4.4), an ultrasonic cleaner can be used as a cleaning method, particularly for instruments with hinges and/or intricate parts. However, many ultrasonic cleaners in regular use have been found to be ineffective in the past because of lack of maintenance and testing or damage in transit. Therefore, it is essential that ultrasonic cleaners are shown to be effective. To enable consistent cleaning of instruments, follow the manufacturer’s operating instructions and ensure all staff use a specified and documented operating procedure (see Section 4.3.2). Do not use ultrasonic cleaners to clean dental handpieces. Test your ultrasonic cleaner quarterly to ensure that it is fully functional (see Section 6). Assess the impact of carrying out these tests in your practice when considering upgrading your decontamination facilities and bear in mind that the preferred method of cleaning is to use a WD. 4.3.1 Points to Consider Before Purchasing an Ultrasonic Cleaner Before purchasing an ultrasonic cleaner ensure that the ultrasonic cleaner complies with the requirements of Scottish Health Technical Memorandum (SHTM) 2030 and has the following features: • control of process variables such as time and temperature; • a lid with an interlock to prevent operation of the cleaner when the lid is open (ultrasonic cleaners must be operated with the lid closed); • a choice of load carrier(s) appropriate to the nature of the devices to be processed; • an irrigation system if devices with lumens are to be processed; • a chamber drain-tap to enable the chamber to be emptied; • a printer (some ultrasonic cleaners have integrated printers that give a permanent record of each cleaning cycle). 14 Cleaning of Dental Instruments 4 Cleaning Methods 4.3.2 Validating the Operating Procedure for Ultrasonic Cleaners It is important that an operating procedure that cleans instruments effectively is validated, documented and then used consistently. To demonstrate valid, reproducible operation of your ultrasonic cleaner: • ensure your machine is installed and tested to the requirements specified in SHTM 2030; • follow a written procedure that you know is effective in cleaning your instruments and includes details of the loading procedures, choice of operating cycle time and temperature and choice of detergent; • detail the water-changing regimen in writing and keep records of each change (change the aqueous solution in the ultrasonic tank at intervals not exceeding 4 hours or earlier if visibly soiled); • use only those detergents that are specified by the manufacturer as suitable for use in ultrasonic cleaners (refer to Appendix 3 for suitable products); • run the ultrasonic cleaner while filled with the water–detergent solution but without a load for the manufacturer’s specified time to de-gas the solution on start up and on subsequent re-fillings; • rinse out the tank after emptying the solution (rinsing will remove soiling before it is filled up again); • drain, clean with a neutral detergent solution, rinse and dry the cleaner when not in use (e.g. overnight). 15 Cleaning of Dental Instruments 4 Cleaning Methods 4.3.3 Ultrasonic Cleaning Procedure If instruments are particularly heavily soiled, briefly immerse them in cold water in the washing sink to remove some of the blood and other visible soil before ultrasonic cleaning. Follow the manufacturer’s recommendations for the safe operating procedure of your ultrasonic cleaner and follow the points outlined below regarding filling and emptying the cleaner. • Ensure that joints or hinges are opened fully and instruments that need taking apart are fully disassembled before they are immersed in the solution. • Place instruments in a suspended basket and fully immerse in the cleaning solution ensuring that all surfaces are in contact with the solution. • Do not overload the basket or overlap instruments because this results in poor cleaning and can cause wear to the instruments. • Do not place instruments on the floor of the ultrasonic cleaner because this results in poor cleaning and excessive instrument movement, which can damage the instruments. • To avoid damage to delicate instruments a modified basket or tray system might also be necessary depending on operational requirements. • Set the timer to the correct setting as per the ultrasonic cleaner manufacturer’s instructions. Close the lid and do not open until the cycle is complete. • After the cycle is complete, drain the basket of instruments before rinsing. • Change the solution when it becomes visibly contaminated or otherwise every 4 hours because the build-up of debris will reduce the effectiveness of cleaning. Ensure staff are aware of the need to assess when a change of solution is necessary as advised in the operational requirements. After ultrasonic cleaning, rinse, dry and inspect instruments for cleanliness and, where possible, check functionality as described in Section 5, before sterilization. 16 Cleaning of Dental Instruments 4 Cleaning Methods 4.4 Washer-disinfectors Using a washer-disinfector (WD) is the preferred method for cleaning dental instruments because it offers the best option for the control and reproducibility of cleaning, and the cleaning process can be validated. WDs are used to carry out the processes of cleaning and disinfection consecutively. A typical WD cycle for instruments includes the following five stages: Flush – Removes ‘difficult’ gross contamination, including blood, tissue debris, bone fragments and other fluid and solid debris. Latest standards indicate that a water temperature of <45°C is used to prevent protein coagulation and fixing of soil to the instrument. Wash – Removes any remaining soil. Mechanical and chemical processes loosen and break up contamination adhering to the instrument surface. Detergents used in this process must be specified by the manufacturer as suitable for use in a WD. Rinse – Removes detergent used during the cleaning process. This stage can contain several substages. Thermal disinfection – The temperature of the load is raised and held at the pre-set disinfection temperature for the required disinfection holding time: for example, 80˚C for 10 minutes, or 90˚C for 1 minute. Drying – Purges the load and chamber with heated air to remove residual moisture. The cycle time depends on the type of machine purchased, and particularly on whether a drying stage is available and used. Time per cycle ranges between 20 and 60 minutes, depending on the model of WD and the wash programme chosen. Incorporate a WD into any plans to upgrade your facilities (taking note of the points outlined in Section 4.4.1). Following installation of a WD, ensure the operating procedure of the WD is validated by a Test Person, and this validation is verified by an Authorised Person (Sterilizers) (see Section 6). Clean all instruments that are able to be immersed in water in a WD if available, except when stated otherwise in manufacturers’ instructions. Follow manufacturers’ instructions to ensure instruments are cleaned effectively and to protect your rights should any clinical or decontamination equipment fail. Train staff in how to use a WD correctly, including testing of equipment. Conduct daily and weekly tests and arrange quarterly tests and re-validation tests (annually and after repair) to ensure your WD is cleaning effectively (see Section 6). 17 Cleaning of Dental Instruments 4 Cleaning Methods 4.4.1 Points to Consider Before Purchasing a Washer-disinfector Different models of WDs are available to suit use on a worktop or on the floor under a worktop. Passthrough machines have doors on two sides, which can facilitate the dirty-to-clean work-flow within a room or between ‘dirty’ and ‘clean’ rooms. When purchasing a WD, obtain advice on model features and the facilities you will require from an Authorised Person (Sterilizers), who can be contacted through HPS. Limitations associated with manufacturers’ instructions Currently, there is a lack of clear guidance or cohesive strategies between manufacturers of cleaning equipment and manufacturers of instruments. Be aware that recommendations from instrument manufacturers might not be fully compatible with those of the WD or detergent manufacturer. If any instruments you are considering buying cannot be satisfactorily decontaminated using a WD, source alternative instruments that can be decontaminated using this method. Considerations for cleaning handpieces There is currently no WD adapted to clean handpieces that has been validated independently as being effective, although at least one manufacturer has done its own validation procedure. If WDs have a handpiece irrigation system then some models require that a special filter is fitted to protect the internal mechanism of the handpiece from extraneous debris during the operating cycle. These filters need to be replaced at regular intervals. 18 Cleaning of Dental Instruments 4 Cleaning Methods An automated alternative to a WD is to use a dedicated handpiece cleaning machine. This uses a pressurised system to clean and lubricate handpieces. However, unlike a WD it does not disinfect. Check with your handpiece manufacturer that you can use a WD to clean your handpieces. However, note that there is little published research to demonstrate the efficacy of the cleaning of the internal mechanism of handpieces by this method. Consult the WD manufacturer for operating details (e.g. whether filters are required) and running costs before purchase. WDs might remove all lubricant during the cleaning cycle and so handpieces might require further lubrication after cleaning. Follow the handpiece manufacturer’s recommendations for lubrication. Practice resources Using a WD requires several resources, including: • appropriate staff training (on installation of the WD), and maintenance, testing and commissioning of the WD; Some manufacturers mark handpieces with the symbol on the left to indicate that they can be cleaned in a washerdisinfector • adequate space and provision of utilities (drainage, water, electricity) and possibly significant modification of premises; • compatible instruments and tray systems; • specified types of water for rinsing (if tap water is not suitable) and a mechanism for producing and/or space for storing the water. Check whether your practice can accommodate the training, maintenance, testing, space and utilities required to run a WD (see Section 6 for guidance on testing and maintenance of WDs). Tray systems for cleaning dental instruments in WDs are recommended where possible. Their use can minimise instrument handling and the risk of sharps injuries. Obtain recommendations from the WD manufacturer for the most efficient design of cassettes for use in your chosen machine and assess whether extra instruments are required (particularly as processing times for WDs are longer than for manual cleaning). • Instruments must be loaded correctly to ensure adequate cleaning. This will be determined at commissioning and testing. Ensure that a written statement of compatibility is obtained from the manufacturer. 19 Cleaning of Dental Instruments 4 Cleaning Methods Use a suitable quality of water for rinsing instruments that is as recommended in the WD manufacturer’s instructions. • Where the mains water supply is soft water of good quality (i.e. free from humic and fulvic acids) freshly drawn drinking water might be allowed for rinsing. • In hard water areas, or where the water is discoloured, use purified water [e.g. Sterile Water for Irrigation BP, freshly produced reverse osmosis (RO) water, freshly produced distilled water]. Softening alone is insufficient because this does not reduce the level of total dissolved solids, which can be left on the instruments as a residue. If purified water is required, choose a type that is suitable for both the WD and the sterilizer in the practice. • Distillation and RO units are a practical option for producing purified water but be aware that these require proper installation, testing and routine maintenance to consistently produce good quality water. Distilled or RO water quality can deteriorate rapidly at a rate that is dependent on the temperature and other local factors. Use within 24 hours of production, and preferably within 4 hours. • Consider buying a distillation or RO unit that can produce purified water at a rate that will avoid the need for prolonged (e.g. overnight) storage. • Advice on water quality can be obtained from an Authorised Person (Sterilizers) (see Appendix 5 for contact details). Commissioning a washer-disinfector When purchasing a WD, specify that installation and commissioning to SHTM 2030 and EN ISO 15883 is part of the contract. Refer to ‘SHTM 2030 Washer-Disinfectors Part 3 Validation and Verification’ for details of what to ask for; Section 4 of this document contains a schedule of installation tests. This information can be accessed via weblinks in the Reference List of ‘Decontamination Into Practice’. Obtaining a validation certificate Following purchase of a WD, ensure that it is validated on site, prior to use, by a Test Person (see Appendix 4). Obtain a validation certificate that is signed by the Authorised Person (Sterilizers) for your records (see Appendix 5 for contact details). An Authorised Person (Sterilizers) is an independent advisor and requires payment for this service. 20 Cleaning of Dental Instruments 4 Cleaning Methods 4.4.2 Using a Washer-disinfector For details of all operational aspects of using a WD, follow the manufacturer’s instructions. Train staff in the correct operation of a WD, including how to perform daily test and housekeeping tasks. An overview of routine testing, including daily tests, is given in Section 6. It is crucial to load a WD correctly because incorrectly loaded instruments will not be cleaned effectively. Therefore, follow an instrument loading procedure that has been shown to achieve effective cleaning in the WD used in your practice. To do this: • do not overload instrument carriers or overlap instruments; • open instrument hinges and joints fully; • attach instruments that require irrigation to the irrigation system correctly, ensuring filters are in place if required (e.g. for handpieces, if specified by the manufacturer). After cleaning, inspect instruments for cleanliness and, where possible, check functionality as described in Section 5, before sterilization. 21 Cleaning of Dental Instruments 5 Rinsing, Drying, Inspection and Care of Instruments Ensure staff are trained in how to rinse, dry and inspect instruments in accordance with the manufacturer’s instructions. 5.1 Rinsing and Drying of Instruments after Cleaning After cleaning either manually or in an ultrasonic cleaner, instruments must be rinsed thoroughly to remove residual soil and detergents and then dried thoroughly. Instruments must not be allowed to air dry as inadequate drying might enable moisture to be trapped, promoting corrosion and/or microbial growth. Immerse clean instruments in clean water in a separate sink or basin dedicated for rinsing clean instruments. Preferably, use the same quality of water for rinsing as is used for sterilization. However, it is acceptable to use freshly drawn soft tap water. In hard-water areas use purified water for rinsing. Use disposable, non-linting towels to dry instruments immediately after rinsing. 5.2 Inspection and Care of Instruments before Sterilizing Inspect all instruments that have been through any cleaning procedure, including processing by a washerdisinfector (WD), to ensure they are clean, functional and in good condition. An illuminated magnifier is recommended because it makes it much easier to see residual contamination, debris or damage. 22 Cleaning of Dental Instruments 5 Rinsing, Drying, Inspection and Care of Instruments 5.2.1 Inspection for Cleanliness Inspect instruments for any visible soiling such as blood or lining materials. It is especially important to check joints, hinges or the serrated surfaces of jaws, which are difficult to clean. If there is any residual contamination, reject the instrument and ensure it undergoes another cycle of the cleaning process. 5.2.2 Functional Inspection Check all instruments that have been through any cleaning procedure, including processing by a WD, to ensure that they are in good working order. Dispose of instruments that are blunt, bent or damaged or show any signs of pitting or other corrosion. Include certification that instruments have been decontaminated with any instruments sent for repair. 5.2.3 Lubrication Lubricate the joints and hinges of instruments before sterilizing to prevent seizing and corrosion. The lubricant used for this purpose must be permeable to steam, water soluble and suitable for sterilization. Follow manufacturers’ recommendations. 5.2.4 Handpiece Care Lubricate handpieces according to the manufacturer’s instructions. Those that have been processed in a WD might have had the lubricant removed and require lubrication again before going into the sterilizer. Use a separate canister for cleaned instruments. Label the canisters so that it is clear which canister is used for unclean instruments, and which is used for instruments that have been cleaned in a WD. Another canister for use with handpieces after sterilization might be required if the manufacturer recommends it. Inadequate lubrication can lead to unnecessary damage to the internal mechanism. The cleaning process is now complete and the dry instruments are ready for sterilization. 23 Cleaning of Dental Instruments 5 Rinsing, Drying, Inspection and Care of Instruments 5.3 Out-of-hours Use of Instruments Preferably, fully decontaminate instruments as soon as possible after use. However, if a patient is seen late or out of normal working hours, clean and dry instruments at the end of the treatment session. Clearly label these instruments as unsafe for handling or use, and continue reprocessing the next working day. • Ideally, this involves reprocessing these instruments through the complete decontamination process, starting with cleaning, because microorganisms can accumulate during storage. Put together written policies for staff regarding out-of-hours use of instruments and ensure the details of these policies are included in staff training. 24 Cleaning of Dental Instruments 6 Validation, Testing and Maintenance of Cleaning Equipment 6.1 Validation Validation is a documented quality assurance procedure applied to each stage of the decontamination process to ensure that decontamination within the dental practice is consistently carried out to the required standard. Validation enables results to be obtained, recorded and interpreted to show that a process will consistently yield instruments that comply with a predetermined specification. This includes a review of the specification against which decontamination equipment [e.g. washerdisinfector (WD), ultrasonic cleaner or steam sterilizer] is purchased to ensure that it will meet the user’s requirements and satisfactory commissioning of the equipment (i.e. installation, operational and performance qualification). Detailed information is available in the Scottish Health Technical Memoranda: • SHTM 2030 Washer-disinfectors, Part 3 ‘Validation and Verification’ • SHTM 2010 Sterilization, Part 3 ‘Validation and Verification’ • SHTM 2010 Sterilization, Part 6 ‘Testing and Validation Protocols’ • SHTM 2031 Clean Steam for Sterilization, Appendix 2 ‘Operation and Maintenance of Clean Steam Generators’ 6.2 Maintenance and Testing of an Ultrasonic Cleaner 6.2.1 Maintenance Always leave the ultrasonic tank clean and dry when not in use to ensure that the surfaces are undamaged and the inlets and drains are free from obstructions, and test regularly. Ensure regular checks of electrical safety are made and keep a logbook of these checks. 6.2.2 Testing Tests to ensure instruments are cleaned effectively in ultrasonic cleaners are obligatory. To test the efficiency of an ultrasonic cleaner an aluminium foil ablation test (SHTM 2030, Part 3, Section 17) is recommended. Tests carried out during commissioning are intended to establish the variation in activity at different positions and levels within the bath and the time required for each test. Repeat a test of cleaning effectiveness as part of your quarterly maintenance programme. Electronic testers Ultrasonic energy meters are now available to monitor efficiency and operating frequency of ultrasonic baths. They are much quicker and more convenient than the classic foil ablation test but currently none have been independently validated. 25 Cleaning of Dental Instruments 6 Validation, Testing and Maintenance of Cleaning Equipment The foil ablation test Using a foil ablation test, the activity of the ultrasonic cleaner is verified by the erosion pattern, which is created on aluminium foil exposed in the bath for a short period. Although practice staff can perform this test, it would usually be carried out by a Maintenance Person. Equipment and material • Aluminium foil of the type sold as aluminium foil wrap for cooking. • Adhesive tape (e.g. autoclave indicator tape or masking tape). • A watch or clock with a second hand. Method • Cut strips of aluminium foil 15–20 mm wide and 12 cm longer than the bath is deep (the rolled end acts as a weight to keep foil vertical in the bath). • Ensure that the water in the tank is at the required level, that the required amount of any chemical additive specified by the manufacturer has been added and that the water in the tank is at the specified operating temperature. • Carry out the manufacturer’s recommended start-up procedure. This will normally include a period of operation to eliminate dissolved gases from the solution in the bath (the de-gassing procedure). • Using strips of adhesive tape across the top of bath, suspend nine strips of the prepared foil in the bath in a 3 x 3 grid. Ensure that the rolled bottom end of each foil strip is no more that 10 mm above, but not touching, the bottom of the bath. • Operate the bath for the predetermined exposure time. This varies typically between 30 seconds and 10 minutes depending on the power rating of the ultrasonic transducers. • Remove the strips from the bath, blot dry and examine. The strips can be filed conveniently by sticking them to a sheet of plain paper using a transparent adhesive tape. • Drain the bath and clean to remove debris of eroded aluminium foil. 26 Cleaning of Dental Instruments 6 Validation, Testing and Maintenance of Cleaning Equipment Results and interpretation • When the foil strips are inspected, the areas that show maximum erosion should be at similar positions on all nine foils and each should be eroded to a similar extent. On re-testing the extent of erosion, the erosion pattern should remain consistent. If the zones of erosion are markedly different on the nine foils it indicates poor uniformity of cleaning. • Poor uniformity of cleaning might be due to failure of one or more of the transducers that produce the ultrasonic vibration in the base of the bath. Result strips taped to paper showing inadequate or uneven erosion patterns A significant change between tests indicates a deterioration or failure in the transducers. If there is no erosion, this indicates complete failure. In the event of any of these findings, withdraw the ultrasonic cleaner from use and send it for repair or replace it. 6.3 Installation and Testing of a Washer-disinfector 6.3.1 Installation Before installation contact the manufacturer to obtain drawings and layouts to help local tradesmen install your machine correctly to conform to specifications. On delivery of the WD the contractor is expected to carry out the installation checks included in the contract as specified in SHTM 2030 to establish that the WD: • has been provided and installed correctly; • is safe to operate; • performs as it should (i.e. according to the purchase specification); • does not interfere with other equipment; • all connected services are satisfactory and do not prevent attainment of the designed cleaning and disinfection performance of the WD. 27 Cleaning of Dental Instruments 6 Validation, Testing and Maintenance of Cleaning Equipment 6.3.2 Routine Testing Periodic testing is required to ensure WDs still meet the validated parameters established on installation. Details of these tests are in SHTM 2030 and include daily, weekly, quarterly and yearly re-validation tests. Conduct the following daily and weekly tests, and ensure that the other testing schedules outlined in SHTM 2030, which involve more detail, are conducted by a Maintenance Person or Test Person, and re-validation is verified by an Authorised Person (Sterilizers). Daily tests • Conduct an automatic control test (see below). • Check spray arm for rotation. • Check spray nozzles for blockage. • Remove and clean strainers and filters. • Inspect instruments visually for cleaning efficacy, using a magnifier to help. Automatic control test This is the main test for ensuring that the WD continues to function correctly. Test procedure • Place a normal standard load, typical of what is used throughout the day, in the chamber of the WD. This can be a routine batch of used instruments that need processing. The important point to note is that this ‘test load’ should be identical each day. • For WDs equipped with multiple cycle capability, select the operating cycle to be tested. If you use more than one cycle routinely then select one operating cycle one day, and the following day select the second operating cycle and so on. This enables the test procedure to fit in as a straightforward routine within the daily workflow. • Start the cycle. • Ensure that a batch process record is made by the recording instrument fitted to the WD. Purchase a machine that has an independent recorder fitted. If the WD does not have a recorder someone has to observe and note the elapsed time, indicated chamber temperatures and pressures at the beginning and end of each stage or sub-stage, and the maximum values during the holding time. Check the printout to ensure that the required parameters have been met. 28 Cleaning of Dental Instruments 6 Validation, Testing and Maintenance of Cleaning Equipment The test is to be considered satisfactory if the following requirements are met: • a visual display indicating ‘cycle complete‘ occurs; • during the whole operational cycle the values of the cycle variables as indicated by the instruments on the WD or shown on the batch process record are within the limits established as giving satisfactory results either by the manufacturer or during performance qualification; • during the disinfection hold period (determined from the indicated and/or recorded chamber temperature) the indicated and recorded chamber temperatures are within the appropriate disinfection temperature band specified; the time for which the disinfection temperature is maintained is not less than previously established, by either the manufacturer or the performance qualification tests, to ensure that the load is maintained at temperatures within the disinfection temperature band for the time specified in SHTM 2030; • the door cannot be opened until the cycle is complete; • the person conducting the test does not observe any mechanical or other anomaly. Weekly test – cleaning efficacy Cleaning efficacy tests are used to demonstrate the ability of the WD to remove soiling and contamination. Methods to determine whether instruments are being cleaned effectively include: • visual inspection (as above; conducted routinely each day); • chemical testing. Chemical testing involves testing, at least once a week, items that are processed in WDs for residual protein after cleaning. A list of tests is available in SHTM 2030 or from the Authorised Person (Sterlizers) who provides the validation certificate for your WD. 29 Cleaning of Dental Instruments Notes 30 Cleaning of Dental Instruments 31 Cleaning of Dental Instruments Notes 32 Scottish Dental Clinical Effectiveness Programme SDcep The Scottish Dental Clinical Effectiveness Programme (SDCEP) is an initiative of the National Dental Advisory Committee (NDAC) and is supported by the Scottish Executive and NHS Education for Scotland. The Programme aims to provide user-friendly, evidence-based guidance for the dental profession in Scotland. Cleaning of Dental Instruments Dental Clinical Guidance SDCEP guidance is designed to help the dental team provide improved care for patients by bringing together, in a structured manner, the best available information that is relevant to priority areas in dentistry, and presenting this information in a form that can be interpreted easily and implemented. ‘Cleaning of Dental Instruments’ is the first of the SDCEP series ‘Decontamination Into Practice’, which aims to help the evolution towards compliance with relevant statutory and mandatory requirements and standards. ‘Cleaning of Dental Instruments’ provides advice on all aspects of cleaning, including organising the decontamination area, cleaning methods and testing of equipment. Scottish Dental Clinical Effectiveness Programme Dundee Dental Education Centre, Frankland Building, Small’s Wynd, Dundee DD1 4HN Email [email protected] Tel 01382 425751 / 425771 Website www.scottishdental.org/cep March 2007
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