Infection Control Manual

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Disinfection of Equipment, Instruments and Dental Impressions

Definition of disinfection

Disinfection is a process used to reduce the number of viable microorganisms but may not inactivate certain viruses and bacterial spores. Disinfection should be limited to equipment, which cannot be reprocessed using other methods and is strongly discouraged in dental practice as a form of sterilisation, as most equipment can be steam sterilized or is available as single use disposable items.

When selecting a disinfectant for heat sensitive equipment, check that it is active against bacterial spores, M. tuberculosis and viruses including HIV, HCV and HBV. The disinfectant must be compatible with the instrument or equipment and not corrode, damage or have a deleterious effect on its function. Always check first with the manufacturer before using a new disinfectant. Finally, read the disinfectant's Safety Data Sheet, as some disinfectants require special conditions for use such as exhaust ventilation in order to prevent adverse reactions occurring e.g. skin hypersensitivity or asthma. An example is Glutaraldehyde which is NOT suitable for general dental practice as it is an irritant and sensitises the skin, eyes and respiratory tract.

You will need to prepare a written COSHH assessment on all disinfectants used in the practice.

 

Procedure for chemical disinfection of heat sensitive equipment

• Instruments and equipment must be cleaned before disinfection (as for sterilisation- see section 6.6)
• When preparing disinfectants staff must wear appropriate PPE (Visor/goggles, mask, heavy duty gloves, plastic apron)
• Room used for disinfection must be well ventilated
• Receptacles used for chemical disinfectant solutions must be cleaned and steam sterilized before use
• Make up the disinfectant at the correct concentration according to manufacturer's instructions
• Disinfect for the recommended contact time (use a timer)
• Devices that can be submerged should be completely immersed in the disinfectant to ensure contact with all internal and external parts
• Remove using an aseptic technique
• Rinse thoroughly in sterile water
• Dry using a sterile non linting cloth
• Inspect for cleanliness

A to Z of Decontamination (list is not exhaustive)

Item	Decontamination requirements
Airways and endotracheal tubes	Single use items. Any re-usable items should be steam sterilized.
Bracket table and handle	Cover with cling film during use; then disinfect with surface disinfectant e.g. alcohol wipe
Brushes (for cleaning equipment)	Discard, or clean and autoclave following use. Store dry.
Burs (diamond, tungsten carbide)	Immerse in enzymic (e.g. Alkazyme) disinfectant, follow manufacturer's instructions on dilution and immersion time. Steam sterilize and dry. Steel burs are a single use item.
Carpets	Not suitable for clinical areas. Vacuum regularly (normally daily). Steam clean periodically.
Curing light	Cover tip with cling film or impervious plastic sleeve. (Tips also available as sterilizerable or as single use disposable). Wipe outer casing with surface disinfectant or alcohol wipe after use on each patient.
Dappens pot	Glass: clean and steam sterilizer; Plastic: single use disposable
Dental Chair and stools	Covering should be intact. Clean regularly with warm water and detergent. Blood/body fluid splashes should be cleaned immediately with dilute hypochlorite solution and wiped with a manufacturer recommended surface disinfectant.
Dental chair switches	Cover with cling film, change between patients, end of session disinfect with surface disinfectant
Dental Handpieces and connectors	Automatic cleaning device recommended or cleaning and pre-oiling according to handpiece manufacturer's instructions prior to placement in vacuum (or if not available a non-vacuum) sterilizer. Handpiece couplings and hose cover with impervious sleeve/cling film; clean with surface disinfectant
Endodontic RCT instruments	Files and reamers most are single use only, but if designated re-usable by manufacturer e.g. some rotary files, then brush clean and place in ultrasonic bath, steam sterilize. Bent or damaged instrument should be discarded.
Face bows	Remove debris and clean, use surface disinfectant, steam sterilize the fork.
Fan (mechanical) and Air Conditioning	Avoid use of fans in clinical areas as difficult to clean effectively. If use is considered essential, then routinely wipe clean with detergent. Regularly change filters and clean air conditioning units.
Furniture and fittings	Should be in good repair and all coverings intact. Damp dust with warm water and detergent. If known contamination, wash with diluted hypochlorite solution. Choose furniture upholstered with wipeable fabrics.
Forceps	Manual cleaning and ultrasonic bath or thermal washer disinfector; Steam sterilize; store in clean dry container /tray. Preferably sterilized in pouches in a vacuum autoclave.
Kidney dishes	Manual cleaning or thermal washer disinfector, steam sterilize; or use disposables
Light handles	Cover with cling film and replace between patents. Clean with surface disinfectant at end of session
Masks	Single use item.
Matrix bands	Single use item
Metal Syringes	Clean and sterilize.
Nail brushes	Single use only (generally not recommended for hand hygiene in dental practice).
Needles	Single use item. Resheath carefully with finger guard protectors or other resheathing device or if not available single handed scoup method. Dispose of plastic syringes and needles as one unit into sharps bin. Consider using retractable safety needles.
Plastic aprons	Single use
Paper points	Use pre-sterilized packs
Radiographic film	Handle with gloves, use barrier pouch
Radiographic film holders and positioning devices	Sterilize, if not heat tolerant then clean by immersion in disinfectant
Radiograph tube- heads and control panels	Protect with cling film (impervious barrier) change after each patient
Stethoscopes	Use 70% isopropyl alcohol wipes on bell and earpieces.
Suction equipment and Spittoon	Disposable suction tips. Clean using warm water and non-foaming disinfectant. Filters changed according to manufacturer's instructions. Tubing and lines disinfected according to chair and spittoon instructions
Thermometer	High-level disinfection according to manufacturer's instructions or use disposable strips. DO NOT AUTOCLAVE
Ultrasonic scalers and handle	Scalers are steam sterilized, cover handles in cling film or impervious plastic sleeves that are changed after each use and wipe connector and hose with surface disinfectant.

 

 

Disinfection of dental impressions and impression trays

Dental impressions become contaminated with saliva, blood and oral bacteria . Less commonly they may become contaminated with respiratory pathogens, which are coughed up into the mouth from the lungs. For example, impressions taken on a patient previously diagnosed with tuberculosis were found to harbour the causative agent Mycobacterium tuberculosis .

Dental impressions:

• All impression must be cleaned and disinfected before being sent to the laboratory.
• Wear gloves, mask, goggles /visor
• All impressions should be rinsed thoroughly in running water to remove all visible signs of contamination.
• Use a disinfectant that is compatible with impression material. Immerse the impression in the disinfectant for the specified time. Avoid spray disinfectants, which are less effective and may create an inhalation risk. Rinse off the disinfectant with water.
• Impression trays:
• Commercially manufactured plastic impression trays are for single patient use only. Do not clean or reprocess then for subsequent reuse. After single use they should be disposed of as clinical waste by the practice or the dental laboratory.

Metal impression trays are reusable and should be thoroughly cleaned, immersed in an ultrasonic bath or processed in a thermal washer disinfector and then steam sterilized.

 

Equipment to be sent for service or repair

Equipment, which has been contaminated with blood/body fluids, or has been exposed to patients with a known infectious disease, must be decontaminated before being sent to third parties for inspection, service or repair (see DB 2003 (05) June 2003). The device or equipment should not expose the recipient to biological, chemical or radiation hazards. Specific advice on decontamination procedures should be obtained from the manufacturer. All equipment to be inspected, serviced or repaired must be assessed and a declaration of contamination status form completed. Sample forms and further guidance can be obtained from the MHRA website. The contamination status form should state whether the item:

• Is contaminated with blood, body fluids, pathogens or hazardous chemicals
• Has been cleaned and /or decontaminated
• The method used for cleaning, disinfection or sterilisation
• Signed and dated to declare that "the item has been prepared to ensure safe handling and transportation".

If equipment cannot be decontaminated (for example if device needs to be dismantled by an engineer), the repair organisation should be contacted and asked if they will accept an item that has not been decontaminated. If accepted, then it should be labelled with its contamination status and packed and dispatched for service/repair. Please note that it is illegal to send contaminated items through the post. If the repair organisation will not agree to the dispatch of the device, then quarantine the item, label with its contamination status and arrange a site visit to the practice by the service/ repair organization