Preventing the spread of contagious diseases

Aims & Objectives

  • To teach readers how droplet-borne pathogens can spread in a dental practice
  • To alert readers to the recent rise in measles cases in the UK and how to identify the symptoms
  • To teach readers about some effective ways of managing the risk of pathogen spread in the dental practice

Learning Outcomes

  • Readers will understand how droplet-borne pathogens can spread in a dental practice
  • Readers will be aware of the recent rise in measles cases in the UK and will be able to recognise the symptoms
  • Readers will be aware of some effective ways of managing the risk of pathogen spread

This article relates to GDC development outcome C

Dental practices have a duty of care to their patients and their staff to keep the practice environment clean and free from harmful pathogens and to minimise the risk of infection. Any patient who visits the surgery could be carrying an undiagnosed illness which they could easily pass on to other patients and practice staff in a number of ways.

Dentists, nurses, hygienists and therapists are exposed daily to pathogens, particularly from those found in blood and saliva which they come into contact with during dental procedures. In addition to this, all staff and patients visiting the practice are at risk of becoming infected by air- or surface-borne pathogens such as those that can survive in the air in droplet form and on surfaces for several hours.

Combatting the most contagious diseases

The advance of science and development of effective vaccines have brought under control many of the most devastating major human diseases, such as smallpox, yellow fever and polio. However, recently there has been a worrying increase in one of the most contagious diseases of all.

Measles cases in Europe tripled between 2017 and 2018 to 82,596 cases, the highest number recorded this decade . Over 90% of the cases were recorded in 10 European countries including France, Italy and Greece. There were 953 cases of measles in the UK in 2018.

According to the World Health Organisation (WHO), measles is a highly contagious, serious disease caused by a virus, which before the vaccine was introduced in 1963, was responsible for an estimated 2.6 million deaths worldwide each year. Most measles-related deaths are caused by complications associated with the disease. Serious complications are more common in children under the age of 5, or adults over the age of 30, and the most serious ones include blindness, encephalitis (an infection that causes brain swelling), and severe respiratory infections such as pneumonia.

Severe measles is more prevalent among poorly nourished young children, especially those with insufficient vitamin A, or whose immune systems have been weakened by HIV/AIDS or other diseases. Unvaccinated young children are at highest risk of measles and its complications, including death. Unvaccinated pregnant women and their unborn babies are also at risk. Any non-immune person (who has not been vaccinated or was vaccinated but did not develop immunity) can become infected.

In the UK, the mumps vaccine is only available on the NHS as a component of the MMR vaccine. MMR was introduced in 1988, with a second dose introduced in 1996. To ensure protection, the NHS recommends two doses of MMR with at least four weeks between doses as not everyone responds to the first dose . The second dose gives them another opportunity to develop a good response to the vaccine and after two doses of the MMR vaccine, about 99 of people out of 100 will be protected against measles.

How droplet-borne pathogens spread

Any person infected with a droplet-borne disease like measles can spread the pathogens by coughing, sneezing or direct face-to-face contact. Once out of the body the pathogens survive in droplet form in the air and on surfaces on which they land. Others are at risk after only 15 minutes in the same room as the pathogens which can enter through the mouth and nose.

As the measles virus can remain active on surfaces for up to two hours[i], it can be spread to anyone else who touches those surfaces within that time period after the infected person has left. One of the biggest potential infection routes within a practice is hand-to-surface / hand-to-patient contact so it’s essential to maintain strict hygiene procedures to keep all surfaces clean.

During patient treatment, surfaces within the treatment room can easily become contaminated by the release of oral fluids resulting from the use of conventional high-speed handpieces and rotary instruments, or when a member of the team touches the surface with contaminated gloves. These surfaces include headrests, X-ray equipment, light handles, control panels and reusable instruments such as handpieces and ultrasonic scaler heads.

[i] https://www.who.int/news-room/fact-sheets/detail/measles

Measles: knowing the symptoms

Two reasons why measles is so successful at spreading is that it is very difficult to avoid airborne infected droplets where they are present. The other reason is that carriers are infectious from four days before the tell-tale rash appears to four days after it has disappeared, so it’s hard to detect. It is still essential for dental staff to be able to recognise the signs when they do present:

  • It starts with cold-like symptoms such as a runny nose, sneezing and a cough
  • A fever which can reach up to around 40°C (104°F)
  • Eyes can be sore and sensitive to the light
  • Small, greyish-white spots on the inside of cheeks
  • After 4 days, a red-brown, blotchy rash appears, which usually starts on the head or upper neck before spreading outwards to the rest of the body

If dental staff do suspect a patient to be infected with measles, it is best to advise them to return home immediately and call their doctor to avoid them spreading the disease further and putting staff and other patients at risk.

Measles: knowing the symptoms

Dental practices can however significantly reduce the risks of surface-to-patient transmission of pathogens with the following recommended procedures:

  • Protect contact surfaces by using disposable single-use barrier products for covering items such as headrests, tubing, turbines and control panels. These should be removed, discarded and replaced after each patient.
  • Clinical contact surfaces local to the dental chair which are not protected by a plastic barrier must be cleaned and disinfected between patients as specified in HTM 01-05 Section 6.62. These include:

Work surfaces

  • Dental chairs
  • Curing lamps
  • Inspection lights and handles
  • Hand controls including replacement of covers
  • Trolley/delivery units
  • Spittoons
  • Aspirators
  • X-ray units
  • After each session, areas and items that must be cleaned include taps, drainage points, splashbacks and sinks.
  • At the end of every day, clean cupboard doors, other exposed surfaces and floors, including those away from the dental chair.
  • Care must also be taken with reusable equipment after cleaning and sterilisation so that they remain sterile and are not re-contaminated by dirty surfaces or gloves.

It is recommended that work surfaces are cleaned with a wide spectrum, microbiocidal solution which has proven efficacy against mycobacteria, fungi, yeast and enveloped viruses such as HIV, HBV, HCV and TB. For use on medical device surfaces, these cleaning and disinfection products should also conform to the requirements of the Medical Device Directive 93/42/EEC and be HTM 01-05 compliant.

The recent resurgence in measles cases in Europe has demonstrated that we can never be complacent about the ability of modern science to keep us safe. Failing health systems in some areas have led to a reduction in vaccines for contagious diseases like measles and there has been an increase in ‘vaccine hesitancy’ amongst some who believe that vaccines may be harmful in other ways. In the face of these trends, dental practices must ensure strict adherence to their hygiene protocols to halt the spread of infection and remain informed and adequately trained to recognise and then mitigate the risks.