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hygiene tribuneDental Tribune Middle East & Africa Edition | November-December 2014 7B The world is very small By Dr. Raghu Puttaiah, USA T he Middle East Respira- tory Syndrome (MERS) is a respiratory condition as- sociated with a specific strain of coronavirus called MERS-CoV. The clinical scenario includes severe respiratory illness, fever, cough and shortness of breath, leading to death in about a third of those infected. While MERS was first reported in 2012 on the Arabian Peninsula, cases have now been reported in over three dozen countries, spanning Asia, Europe and North America. While this disease has been not- ed to spread from those infected to their caregivers or those liv- ing in close contact, it has not yet been found to spread in community settings as seen dur- ing the severe acute respiratory syndrome (SARS) outbreak in Asia that saw over 8,000 people infected, resulting in about 9 per cent mortality. Only two cases have been detected in the US, both of whom had a recent his- tory of travel to Saudi Arabia. The Centers for Disease Con- trol and Prevention (CDC) and the World Health Organization (WHO) are concerned about the potential of MERS to spread globally and therefore are pro- viding information and control measures similar to those pro- vided during the SARS and influ- enza A (H1N1) outbreaks. With respect to dentistry, if there is a vaccine available for any infec- tious disease of public health concern, we must take it before it affects us. With regard to infec- tion control, if we as dental care providers feel ill or feel that we are about to fall ill, we must not go to work but stay away from people, including co-workers and patients, until the symptoms resolve. We should also inform patients prior to their appoint- ment that, if they are not feeling well, they should reschedule the appointment. Basic infection control meas- ures, such as frequent hand- washing, wearing a mask, and following standard and addi- tional precautions, the last be- ing specific to MERS, must be adhered to strictly. The world is very small with respect to travel and the spread of disease from one continent to another can happen within a day. Keeping abreast with rapidly changing information on diseases such as MERS from reliable sources, such as the CDC, WHO, Associa- tion for Professionals in Infection Control and Epidemiology, and Organization for Safety, Asepsis and Prevention, is necessary for the dental team. Diseases can spread easily if infection control measures are not adhered to. (Photo: lightpoet/Shutterstock) Using personal protective equipment such as surgical masks, safety glasses as well as disposable gowns and gloves is vital. (Photo Tyler Olson/ Shutterstock) Infection control in dentistry has never been more essential ByDr.SafuraBaharin,Malaysia D emand for dental treat- ment has been increas- ing in recent years as people have become more aware of their oral health and the benefits of good dental aes- thetics. Maintaining and prac- tising stringent cross-infection control procedures therefore have never been more essential to ensure the health and safety of dentists, dental hygienists and assistants, as well as other sup- porting staff who may be indi- rectly involved in the treatment process. Dental professionals are at high risk of cross-infection. A report published in 1999 has shown that in developing countries, for example, the number of dental staff contaminated during treat- ment is increasing by almost 6 per cent each year.[1] Research has shown that infectious micro- organisms can be transmitted by blood or saliva via direct or indirect contact, aerosols, or contaminated instruments and equipment.[2] As stated by the US Centers for Disease Control and Prevention (CDC) in their 2003 guidelines, the transmis- sion of infectious disease can oc- cur in four ways: direct contact with blood or body fluids, indi- rect contact with contaminated objects or surfaces, contact with bacterial droplets or aerosols, and inhalation of airborne mi- cro-organisms.[3] The most likely mode of trans- mission in dentistry is through inhalation of bacterial aerosols or splatters. Their potential health hazards are well docu- mented and acknowledged.[4–9] Both can be host to a large vari- ety of micro-organisms and vi- ruses, which can be infectious to susceptible individuals. During treatment, the dentist’s face and patient’s chest are most affected by splatter, as the majority of the splatters are radiated towards them.[10, 11] According to stud- ies, the most contaminated area on the dentist’s face during treat- ment is around the nose and in- ner corner of the eyes.[11] Splatter consists of large parti- cles of greater than 100 µm gen- erated during the use of dental equipment, such as turbines, ultrasonic scalers, or water and air syringes. Owing to this, splat- ter tends to travel in a trajectory, thereby contacting objects in its path. Aerosol consists of smaller particles that can remain in the air for a long time and travel with air currents. Most dental aerosols are less than 5 µm in di- ameter; therefore, they are able to penetrate and stay within the lung, causing respiratory or oth- er health problems. Among den- tal procedures that produce high aerosol concentration are ultra- sonic scaling, tooth preparation using high-speed handpieces, and dental extraction involving bone removal via a dental hand- piece.[8] The World Health Organiza- tion (WHO) has reported a rise in airborne infections world- wide. Tuberculosis in particular has increased in the developing world.[12] It has been stipulated that the risk of exposure to tu- berculosis in susceptible DHCP is greater than in healthy indi- viduals. Bennett et al. concluded that dentists and their assistants, who are exposed for approxi- mately 15 minutes during peak aerosol concentration, have a slightly higher risk of exposure to Mycobacterium tuberculosis than the general public does.[9] During this period, the DHCP inhales about 0.014–0.12 µl of aerosolised saliva, which may contain viable pathogens that can have a detrimental effect on the health of susceptible DHCP. With all of this in mind, it is the responsibility of DHCP to adhere strictly to recommended infec- tion control guidelines and poli- cies. Several measures should be taken to reduce and control airborne contamination in the dental clinic. For example, it has been demonstrated that the use of a mouthrinse, high-volume evacuation or a combination of both methods significantly reduces the number of colony- forming units in aerosols emit- ted during ultrasonic scaling. [13] Routine use of rubber dam isolation provides a clean and dry area for placement of dental restorations, prevents salivary and blood splatter, and protects the patient’s mouth and airway. Using personal protective equip- ment (PPE), such as surgical masks (with at least 95% effi- ciency against particles 3–5 µm in diameter; changed for every patient or every 20 minutes in an aerosol environment or 60 min- utes in a non-aerosol environ- ment), safety glasses with lateral protection to prevent contact with eyes, as well as disposable gowns and gloves to reduce the penetration of or contact with bacterial aerosols and splatters, is vital. Regular maintenance of the air- conditioning system is recom- mended too, as good ventilation has a diluting effect on the air- borne microbial load, especially atnightwhentheclinicisclosed. [14] Air samples taken at differ- ent times at a multi-chair den- tal clinic showed that bacterial aerosols are more concentrated during treatment and that there is higher concentration of circu- lating bacterial aerosols at the beginning of the day, which may be related to reduced ventila- tion.[14] Residual bacterial aero- sols can be removed through air filters or ultraviolet light. As splatters can travel as far as the door or supply counter in the middle of a multi-chair dental clinic,[14] all clean, un- used instruments and equip- ment should be kept in closed cabinets or drawers to prevent contamination. Other important measures that must be taken to prevent cross-infection include adequate sterilisation of den- tal instruments, disinfection of work surfaces before and after each dental procedure, disinfec- tion of all dental materials and work sent out to the laboratory, and regular maintenance of the dental water lines and equip- ment, which has the potential to harbour bacteria. All dental water lines should be purged at the beginning of each day for between 5 and 10 minutes and flushed thoroughly with water, as residual water may become contaminated overnight and bi- ofilm may develop along the in- ner side of the tube. Purging will result in a significant decrease in bacterial counts.[15, 16] The Canadian Dental Associa- tion recommends running high- speed handpieces for 20–30 seconds after each treatment to purge all potentially contaminat- ed air and water. This procedure has been proven to reduce the bacterial load in the water line significantly.[17] Blood cells, as well as bacterial and viral par- ticles, can survive inside hand- pieces even after disinfection. They must therefore be steri- lised between patients.[17, 18] The clinic floor should be disin- fected and cleaned with an an- timicrobial disinfectant solution at least twice per day to eradi- cate any bacterial residue from splatter or aerosols. It is a well-known fact that pri- vate dental clinics sometimes employ dental assistants who have not received certified train- ing. Improperly trained person- nel, however, may lead to poor infection control practices. It is the responsibility of every dentist to educate and train his or her assistants in the standard proce- dures. Furthermore, DHCP im- munisation status should be up to date. Eliminating the risk of expo- sure to dental aerosols remains a difficult task. The best way to reduce the risks, however, is to employ routine cross-infection protocols recommended by the health authorities, such as the CDC, WHO and ministries of health. To date, various infection control reports and procedures have been published to inform and educate dental health care personnel (DHCP) about the im- portance of practising adequate infection control. Editorial note: A complete list of references is available from the publisher.