Personal protection for prevention of cross-infection
Personal protective equipment (PPE) such as gowns, goggles, masks and disposable gloves form a protective barrier to reduce contamination of clothing, skin and mucous membranes from patient’s body fluids or splatter. The Health and Safety at Work Act 1974 and the subsequent legislation place a duty of care on employers to provide a safe working environment for their staff, provide PPE and train staff to use it appropriately. Staff and students must ensure their own safety by wearing PPE. Selection of PPE must be based on a risk assessment of the associated hazard and likelihood of transmission of microorganisms to the patient. The practice of infection control policy should reflect:
- Type and duration of the task
- Potential for exposure to blood and body fluids
- Potential for contamination of non-intact skin or mucous membranes
PPE will function effectively only if selected, worn, removed and discarded correctly. In terms of risk management and according to the law, PPE is considered a ‘method of last resort’ as PPE is not foolproof and only reduces rather than eliminates the risk (Table 6.1).
Under the European law, PPE is classified as a medical device. Therefore, only products carrying the European CE mark denoting that the product fulfils specified performance standards should be worn.
|Hierarchy of infection control procedures for personal protection||Examples|
|Elimination of the hazard||Single-use instruments|
|Isolation of the hazard||Safety needles|
|Work practice controls||Hand hygiene|
|Work behaviour controls||User disposes of sharps|
|Administrative controls||Infection control policy|
|Personal protective equipment||Masks, gloves, aprons|
When used correctly, wearing gloves:
- Protects hands from contamination with blood, saliva and microorganisms
- Reduces the risk of cross-infection
- Protects hands from toxic and irritant chemicals
- Does not prevent sharps injuries, but the wiping effect of the glove reduces the risk of contamination
Gloves should be worn during routine dental and surgical treatment, when cleaning instruments, handling waste or mopping up spills. If they are not removed at the end of a task, they become equivalent to ‘a second skin’, acting as a source of infection. Acquisition and growth dynamics of microorganisms are similar on bare and gloved hands. Beware: wearing gloves can give a false sense of security to the wearer as they do not provide complete protection against hand contamination.
Best practice guide: safe use of gloves in the dental surgery
- Hands must be washed before donning gloves. Never consider gloves to be an alternative to hand washing
- Changing your gloves between patients prevents cross-transmission between patients and contamination of hard surfaces in the surgery. Do not touch patient’s notes, pens, computer keyboards, door or drawer handles, or your face with gloved hands (see Chapter 8)
- Never reuse single-use disposable gloves. There is clinical evidence to demonstrate that glove reuse is associated with transmission of MRSA and Gram-negative bacilli
- Never wash single-use gloves; it reduces the barrier properties
- Keep glove wear to a minimum. Gloves should be applied immediately before starting treatment and removed as soon as the activity is complete
- Dispose of gloves as hazardous infectious waste
- Change gloves during very long procedures. After prolonged use, approximately 9–12% of gloves develop perforations or become porous due to hydration of the latex and may leak. Hepatitis viruses have been transmitted via minor glove perforations
- Changing your gloves during long procedures reduces excess sweating, which in turn decreases dermal infections or inflammation
- Remember that hands are not necessarily clean because gloves have been worn. On removing gloves, the patient’s microorganisms can be transmitted from the external surface of the glove to the dentist’s hands and need to be removed by hand hygiene
Natural rubber latex (NRL) gloves and nitrile gloves permit good manual dexterity, are impermeable to microbes and are the commonest types of glove used or clinical procedures (see Table 6.2).
Double gloving has been recommended for high-risk surgical procedures. Using a coloured inner glove increases the user’s awareness of glove perforation during surgery.
Reports on the prevalence of latex sensitivity amongst health care workers (and patients) have risen to 6–18%, paralleling the increased clinical use of latex gloves from the mid-1980s onwards. Latex sensitivity is particularly common amongst dental students and staff, and can develop even after successfully wearing NRL gloves for many years. Sensitivity occurs after inhalation of airborne latex antigens or absorption through damaged skin. NRL is a plant product, but other chemicals are added during fabrication of the glove to imbue it with strength, elasticity and flexibility. Varying amounts of NRL and chemical residues may still be present in the glove as a consequence of the manufacturing process. It is advised to wear gloves with low levels of extractable proteins (<50 µg/g of latex proteins) and chemical accelerators (<0.1% w/w of residual accelerators) to minimise the risk of sensitisation.
|Type of glove||Properties||Allergies|
|Natural rubber latex||Impermeable to BBV, close fitting, do not impair dexterity and are not prone to splitting resistance to water-based chemicals||Not suitable if allergy to NRL or accelerator|
|Acrylonitrile (nitrile)||Impermeable to BBV, close fitting, do not impair dexterity and are not prone to splitting (lowest failure rate under stress conditions), resistance to solvents and oil-based chemicals||Not suitable if allergy to nitrile or accelerator in NRL gloves|
|Polychloroprene (neoprene)||Impermeable to BBV||Suitable if allergy to NRL|
|Vinyl||Impermeable to BBV and has similar properties to NRL when made to the European Standard. If not, vinyl may be permeable to blood-borne viruses, rigid, inflexible and break down in use||Suitable if allergy to NRL|
|Copolymer (multipolymer synthetic styrene-ethylene-butadine-styrene), e.g. Tactylon||Similar elasticity and strength to NRL||Contains no NRL proteins and chemicals and are suitable for people with NRL sensitivity|
|Polythene||Permeable, ill-fitting and prone to splitting and tearing, not suitable for clinical use||Not applicable|
BBV, blood-borne virus; NRL, natural rubber latex.
Reactions are classified as:
- Delayed hypersensitivity (type IV) – resulting in contact dermatitis, rhinitis and conjunctivitis. This is the most common hypersensitivity reaction to NRL or accelerating agents. Response occurs between 6 and 48 hours after exposure
- Immediate hypersensitivity (type I) – asthma, urticaria, laryngeal oedema and anaphylactic shock/collapse. Response occurs 15–30 minutes after exposure
The risk of allergic reactions is triggered not only by latex gloves but also by other latex-containing devices, e.g. rubber dam, syringe and medication vial bungs, prophylaxis cups, orthodontic elastics etc. In practices with sensitised individuals, all the dental team may need to change to non-latex gloves due to the generation of aeroallergens in the surgery environment. Susceptible clerical staff who do not have direct contact with the patient can also become sensitised as the latex aerosols travel on air currents permeating office areas and waiting rooms. Environmental contamination with latex proteins can be reduced by: good ventilation, regular changes of ventilation filters, extensive vacuuming and cleaning of surface contaminated with latex allergens. Equipment in the dental emergency kit should also be free from latex.
Treatment and avoidance strategies are most effective when initiated early. This relies on recognising the symptoms of immediate and delayed hypersensitivity reactions both on oneself and in patients. If latex sensitivity is suspected, the student, staff member or patient should be referred for specialist advice. Individuals who have experienced a type I reaction to NRL are strongly advised to wear a Medic Alert bracelet.
Alternative to NRL gloves that have similar physical properties, i.e. do not impair dexterity and are not prone to splitting and are impermeable to blood-borne viruses, are shown in Table 6.2. According to Health and Safety Law in the UK, staff sensitised to NRL gloves must be supplied with appropriate alternatives by their employer. In response to their medicolegal requirements, a number of dental schools and health care centres have opted to go latex-free as a prophylactic measure to prevent triggering problems in patients, students and staff.
Patients may not always be aware that they have a latex allergy. Individuals who are atopic (predisposition to allergic reactions, e.g. hay fever, asthma and eczema) are at an increased risk of developing a hypersensitivity reaction to NRL.
Best practice guide: managing latex allergies
- The medical history includes a question on latex allergy (e.g. hypersensitivity reaction following contact with household gloves, blowing up balloons, or food allergies to banana, avocado and kiwi fruit which possess shared antigens with NRL)
- If allergy is known, ensure that dental notes are clearly labelled
- Use l/>