CHAPTER 1 Health and Safety, Occupational Hazards and Infection Control in the Dental Workplace
It is essential that dental nurses are aware of the hazards in the dental workplace and the health and safety actions that you can take to avoid harm. Human error is responsible for most risks in a workplace.
All dental practices must have in place policies and procedures that guide staff how to respond appropriately when a hazard is anticipated and to reduce risks. Local policies and procedures are based on national health and safety regulations.
As a dental nurse, you need to be aware of these regulations, as they will underpin your day-to-day actions regarding your own and others’ health and safety in the dental environment. The most important Act, which was a major advance in health and safety, is the Health and Safety at Work etc. Act 1974.
The Health and Safety at Work etc. Act 1974 applies to all workplace premises, including dental surgeries. It makes it clear that all employers are responsible not only for the health and safety of their staff but also of anyone who might be on their premises, such as patients or suppliers. All staff and visitors to a workplace should also act in a responsible manner and prevent any hazards occurring that may cause injury to themselves or others.
If there are five or more employees in the workplace, the employer must have a written health and safety policy statement. Does your workplace require this? If it does, find out where it is located and who is responsible for it.
The workplace room temperature should reach at least 16 °C after one hour and all rooms should have thermometers to check this. Interestingly, there is no legislation covering temperatures that are high!
Enclosed workplaces such as a dental surgery should be ventilated with sufficient fresh or purified air to minimise exposure to dust, mercury, chemicals, nitrous oxide and disinfectant vapours. An open window will usually provide adequate ventilation, but mechanical ventilation or air-conditioning units could be considered. These should provide at least 5–8 litres per second of fresh (not recycled) air per occupant. The relative humidity should be between 40% and 70%.
All dental practices should have a first aid kit as well as the required emergency kit (see Chapter 2). All dental surgeries must also keep a stock of emergency drugs on the premises. Surgeries in which inhalational sedation is performed have further requirements to fulfil, to ensure nitrous oxide and any other gas levels are minimised.
Disinfection: a process by which the number of viable harmful micro-organisms is reduced in an area, e.g. a worktop in a dental practice. Disinfection does not get rid of certain micro-organisms, such as some viruses, or destroy certain forms of harmful micro-organisms, such as spores. Therefore it is only used for cleaning those areas of a dental clinic that only need to be acceptably safe. Disinfection can by carried out using special chemicals called disinfectants or by using heat.
A risk assessment is simply a careful examination of what, in the workplace, could cause harm to people. Doing a risk assessment helps employers decide whether they have taken enough precautions, or should do more, to prevent harm from occurring to themselves, their staff or others.
Sterilisation: a process by which an object is rendered free from all viable harmful micro-organisms, including viruses and bacterial spores. Therefore this method is used to decontaminate instruments that will be used inside a patient’s mouth.
Accidents occur in most workplaces, and dental premises are no exception. Accidents are more likely to happen when staff are not concentrating on their activities or are distracted. Obvious physical dangers to patients, staff and others include:
The hands and eyes are especially vulnerable when caustic fluids, needles, scalpels, wires or lasers, hot or rotating instruments are used. Risks related to the use of needles are explained in more detail in the section on ‘Infections and inoculation injuries’ (p. 14).
Staff and patients should always wear glasses or other eye protection during procedures involving the use of dental handpieces/burs, grinding or polishing, cutting wires, use of caustics or instrument cleansing.
Much of the equipment used in dentistry constitutes some hazard to staff and sometimes to the patient or others. All equipment must therefore be carefully and regularly maintained by an appropriately trained person. This is covered in more detail below.
All accidents and injuries to staff or patients or visitors while on the premises, however apparently trivial, should be recorded in an accident book. Her Majesty’s Stationery Office (HMSO) publishes an ‘Accident Book’, which is suitable for use in the dental environment.
Employers must notify the HSE of accidents causing death or ‘major injury’ to any person or ‘dangerous occurrences’, even if there has been no death or injury. They also have to keep records of the event.
Thus, for example, in the dental practice, a compressor or steam steriliser (autoclave) explosion could be notifiable, as could a mercury spillage. In case of doubt of whether an injury should be reported, the advice of the local HSE office should be sought.
Steam steriliser (autoclave): a pressure vessel in which steam at high pressure is produced. When instruments are placed in the steam steriliser for a certain amount of time, the high temperatures in the steam help to kill the harmful micro-organisms or their spores that may be attached to the instruments.
Reports related to RIDDOR should be immediately given by telephone to HSE, and a completed accident report form (2508) sent to the HSE within 10 days. Incident reporting forms can be downloaded from the HSE website (www.hse.gov.uk/forms/incident/f2508.pdf) or obtained from The Stationery Office Bookshop (www.tso.co.uk/contact). A copy of the completed 2508 form should also be kept by the employer.
If the incident does not result in a reportable injury but clearly could have done so, it is classed as a dangerous occurrence and must also be reported immediately by completing form 2508. A full list of what are ‘dangerous occurrences’ and the employer’s responsibilities are given in the RIDDOR 97 leaflet. (A needlestick injury (p. 14), involving an infected patient may also fall in this category.)
Although RIDDOR applies to all places of work including dental premises it excludes accidents to ‘patients when undergoing treatment in a hospital or surgery of a doctor or dentist’. That exclusion only applies to patients when undergoing treatment – the RIDDOR rules do still have to be followed if, for example, a patient breaks a leg on the surgery doorstep.
If the employer is notified by a doctor that an employee has a reportable work-related disease or infection (e.g. occupational dermatitis, occupational asthma, tuberculosis, hepatitis B, legionnaires’ disease), the HSE must be sent a completed disease report form (2508A; available at: www.hse.gov.uk/forms/incident/f2508a.pdf).
Allergic reactions are common and usually minor but some are potentially lethal. People with asthma, eczema and some other conditions often have underlying allergies. Sometimes allergic reactions can be very severe (called anaphylaxis; see Chapter 2).
Many allergies have a hereditary component but the prevalence of allergies appears to be increasing. Table 1.1.1 lists some common allergens.
|Source of Allergen||Examples|
|Food products||Milk, nuts, egg, shellfish|
|Environmental||Animal hair, dust mite, pollen|
|Latex||Condoms, elastic bands, gloves|
|Dental materials||Amalgam alloy, gold, mercury, resin-based materials|
Latex allergy has become a significant clinical problem, along with allergies to iodine, plasters (e.g. Elastoplast and Band-aid) and drugs (remember this with the acronym LIED – Latex Iodine Elastoplast Drugs). Latex products are common in the home and workplace including clinics, wards and operating theatres. Therefore allergy is an important occupational problem, especially with handwashing using abrasive materials, which increases the risk of sensitisation. Allergic reactions to latex have become increasingly common since the use of protective medical/dental gloves became mandatory following the advent of HIV/AIDS. Latex exposure may occur via the skin, mucous membranes, or respiratory tract (see Subchapter 4.1) with inhalation of latex glove powder (natural rubber latex (NRL) allergens may attach to lubricating powder, and become aerosolised, causing sensitisation; or, in those who are allergic, they can cause respiratory, ocular or nasal symptoms).
‘Low-allergen’ latex gloves are available but there is little certainty that these offer any real benefit. People who have allergies to one type of substance are more likely to have allergies to others; patients with latex allergy, for example, may react to foods with allergen cross-reactivity such as avocado, banana, chestnut and kiwi.
Sensitisation: a change in response by the body to a foreign substance, usually an allergen, so that on subsequent exposures to that substance the body shows a heightened immune response (see Subchapter 4.1).
Many items used in dental practice can sometimes contain latex (Box 1.1.3) and even equipment and laboratory work previously handled with latex gloves may elicit an allergic response.
* Latex is present in some rubber dental local anaesthetic cartridges, stoppers or plungers, where either the harpoon penetrates or where the flat piston end of a self-aspirating syringe rests. At the other end of the cartridge is the diaphragm, which the needle penetrates. Any of these components may contain latex. Although there are no documented reports of allergy due to the latex component of cartridges of dental LA, the UK preparation of prilocaine (Citanest) contains no latex.
Identify all the dental materials and instruments marked with ** in Box 1.1.3 in your workplace.
To avoid future allergic reactions, known allergens should be avoided, which is easier said than done. This is because sensitive individuals may react to minute traces of an allergen, and because allergens can be present in the most unexpected places.
Patients who have had serious allergic reactions such as anaphylaxis (see Chapter 2) are also usually advised to always carry with them adrenaline for subcutaneous self-injection in the event of a reaction (e.g. Epipen). Affected individuals are usually advised to wear a warning emblem such as Medic-Alert.
Occasionally dental staff are victims of assault by patients who may be drunk, stressed, have mental problems or may be drug abusers. Potentially dangerous incidents should be defused where possible. If you are assaulted, the most effective response will be to:
Several acids (e.g. phosphoric acid, chromic acid and trichloroacetic acid) and corrosive agents (e.g. sodium hypochlorite) are used in the dental surgery and can cause burns if they are not used carefully. Many other stronger acids and corrosives are used in the dental laboratory (e.g. hydrofluoric, sulphuric and nitric acids, and caustic soda or sodium bicarbonate). All acids and caustic solutions should be stored safely in appropriate and clearly labelled containers, and proper safety precautions should be taken when handling these materials.
Thermal burns can happen when taking out hot instruments or materials from steam sterilisers or microwaves. Several dental instruments, such as extraction forceps, elevators and metal mouth gags, in particular, retain heat for several minutes after being sterilised and so can cause burns to staff and to patients if used immediately after sterilisation. Handling dental handpieces that have overheated during use can also cause heat burns. This often happens because of the difficulty in gauging their temperature through the gloves that all staff are required to wear in the clinic.
Hot wax knives and Bunsen burners are also common causes of burns; long hair and gloves or clothing can catch light in a Bunsen flame. Hot air blowers can reduce this danger, although they take somewhat longer to heat objects.
Other possible causes of thermal burns in the dental environment include handling hot gutta-percha, dental composition, wax and boiling water, lasers, diathermy and even heated operating lights. Diathermy accidents have resulted from metallic parts of the dental chair becoming part of the path of the current – the localised increase in current density can then cause superficial burns of the skin.
All dental surgeries and laboratories must undertake risk assessments of all chemical and potentially hazardous substances used in the premises. The results of the assessments must be recorded in a COSHH report. The report must include:
Read the COSSH reports of five hazardous materials that are used in your dental practice. See also the COSSH publication ‘Working with substances hazardous to health’ (www.hse.gov.uk/pubns/indg136.pdf).
A dental nurse may be exposed to anaesthetic gases (nitrous oxide) and vapours for a significant part of their career if the equipment used to administer the gases is faulty, poorly maintained or used without an effective scavenging system, or if the agents are misused. These gases, which are also called inhalational agents, are used in conscious sedation (nitrous oxide) and general anaesthesia (nitrous oxide, isoflurane, enflurane, sevoflurane and desflurane; halothane is no longer commonly used – see below). Anaesthesia is covered in detail in Chapter 13.
Under normal working conditions, our mental and nervous responses, that is, how alert we are and how quickly and appropriately we react to situations, are not much impaired by exposure to inhalational agents. However, if a clinician is exposed to excessive amounts of these gases or over a long period of time, not surprisingly, their responses can be impaired. They may also develop numbness, difficulty in concentrating, paraesthesias (‘pins and needles’) and dizziness. Nitrous oxide exposure for prolonged periods can also have adverse effects on other organs of the body, for example the heart, liver and bone marrow, and the reproductive organs.
Halothane and some other halogenated inhalational agents (sevoflurane and desflurane) can cause severe liver dysfunction (called hepatotoxicity) and problems with the beating of the heart (called arrhythmias). Therefore halothane is no longer recommended for use in adults. Only occasional hepatotoxicity has been reported with enflurane and isoflurane.
The Electrical Equipment (Safety) Regulations 1994 state that all electrical equipment should be constructed and designed for safe use when connected. This should be achieved by providing protection against electric shock through a combination of insulation and a protective earthing conductor. The main hazards from electrical equipment are:
Electricity plugs, cables, etc. should be inspected every six months. All electrical equipment should be regularly tested by an appropriately qualified person at least every two to three years, with records kept of the test results.
Eyes need protection from foreign bodies, infected material, chemicals and the various forms of radiation used in dentistry – lasers, light sources for curing (ultra-violet/visible blue or white halogen light) and X-rays. These are covered in more detail on page 16.
Curing: the process of hardening of tooth-coloured materials that are used mainly to fill teeth with cavities. The materials come in paste form and harden either by a chemical reaction or on application of a special light (see Chapter 9).
Patients must always be provided with adequate eye protection – particularly if they are being treated in the supine position (lying on the back) and for procedures being carried out under conscious sedation or general anaesthesia.
All clinical staff should always wear protective eyewear at work. Objects such as bits of fillings can behave like projectiles and fly out of the mouth at speeds of over 10 m/s when using drills at 250 000 revolutions per minute (rpm). The ends of orthodontic and other wires should be held in mosquito forceps, and when cutting, the wire should always be held between two forceps so that the cut end does not fly off and cause eye damage.
Special eyewear is needed for work with lasers and with curing lights. Remember that ordinary dark glasses do not filter the hazardous wavelengths of lasers and curing lights. Rather, because they absorb visible light, they can dilate the pupils (open them wider) and therefore worsen the problem because more of the hazardous light rays can now enter the eyes. Contact lens wearers should be careful not to get powders or other materials behind their lenses.
Human error is responsible for most fires and explosions. The main causes of fire in a dental practice or similar place usually are: electrical faults (see p. 12); careless use of matches; incorrect use of flammable gases (e.g. oxygen) and fluids; and non-electrical heating.
Employers must comply with fire safety regulations. This means carrying out a fire risk assessment to determine what precautions are needed and putting in place fire precaution measures. If there are five or more employees, the fire risk assessment must be written down.
BOX 1.1.5 Steps to Take in the Event of a Fire
Dental staff are commonly exposed to respiratory infections, mainly ‘colds’, and other viral throat and chest (respiratory) infections. Other more serious respiratory hazards are ‘flu’ (influenza), tuberculosis (TB) and, to a much lesser extent, Legionella infection (also called legionnaires’ disease). All these infections could also be transmitted to patients or others (see Subchapter 1.2).
The main infectious hazard in the dental practice is contact with infected body fluids (blood, saliva, etc.). Infections can be transmitted via sharps injuries (needlestick injury; inoculation, particularly those caused by viruses such as hepatitis B, hepatitis C and human immunodeficiency virus (HIV). Prions, which cause Creutzfeldt–Jakob disease (CJD), are virtually impossible to destroy. MRSA (meticillin-resistant Staphylococcus aureus) infection is mainly a healthcare-associated infection (HCAI).
Inoculation injuries include all incidents where a contaminated object or substance enters the body through a breach in the skin or a mucous membrane (see Subchapter 4.1) or comes into contact with the eyes. Typical examples of inoculation injuries are: