History of Infection Control PDF

A HISTORY OF INFECTION CONTROL Semmelweis 1847 Ignaz Semmelweis 1847 - doctor in obstetrics in Vienna - investigated the post delivery mortality rates of mothers - doctor delivers a baby = 18% death rate of moms (contaminated by cadavers passing to mom) - midwife delivers a baby = drops to 2% - came up doctors to wash their hands = dropped to 2% death rate - Has 2 important principles - nosocomial infection - Healthcare has the potential to make people sick - infection control - Interventions can be undertaken to reduce this risk - superiors didn’t impose handwashing, installed ventilation system to hospitals (thought spread by miasma, foul smelling air) The Germ Theory of Disease Louis Pasteur (modern biology, suggests vaccines), Jacob Henle & Robert Koch - Miasma is challenging - microorganisms were responsible for infections Joseph Lister 1867 - Pasteur’s research - delivers antiseptic surgery in 1867 - Success in 19th century - find chemicals that would disinfect not only the wounds he operated on (antisepsis) but also the hands of the operators and the instruments (asepsis). - Research spreads in Europe and America William Halsted - Goodyear Rubber Company, rubber gloves (worn by theater nurses) Joseph Bloodgood - started using gloves to undertake surgery Infection Control in Dentistry Emerges Willoughby Miller 1891 - Disinfection in dental instruments reduces risk of patient-to-patient transmission (syphilis) - boiling of linen - single use of rubber dam - bioburden on instruments reduces efficacy of chemicals to sterilize instruments - recommends they are scrubbed first - Boiling water is preferred method of instrument reprocessing Hugo Davidsohn 1888 - The efficacy of boiling surgical instruments demonstration Young 1902 - describes how a device to boil dental instruments could easily be made Fossume 1905 - most telling and thought-provoking articles made - dentists don't do infection control because of time and cost; plus ça change! - implementation of infection control is a moral and intellectual obligation of modern dentist, values of professionalism. USA 1915 - guidelines on infection control in dentistry issued by the Public Health Service under Hygienic Laboratory, later became part of National Institutes of Health H. E. Hasseltine (guidelines) - Asepsis - Validation - cross infection - instrument reprocessing - role of cleaning prior to sterilization - methods of sterilization - autoclaves and Arnold (non-pressure) devices has role in preparing linen and glassware, boiling water is favored for instruments - Moist heat in sterilizing = 80° C - reprocessing handpieces = challenged by today - Single-use instruments and equipment = endodontic files and paper cups for patients - highlighted the role dental schools play in infection control - maintenance of cuspidor, role of protective barriers, albeit linen Hepatitis McDonald 1908 - proposed that infectious jaundice was due to a virus MacCallum 1947 - classified viral hepatitis as A (infectious) or B (serum) 1940s - awareness of viral hepatitis posing a public health problem in many parts of the world 1952 - World Health Organization addresses problems posed by hepatitis - parental penetration of needles contaminated with blood transmits the disease. Mid-1950s - hypodermic needles and syringes are reused - hepatitis epidemics would break out after vaccination programs - Dentistry, a potential risk in transmission of hepatitis B - chemical disinfectants for instruments isn’t effective Baruch Blumberg and Harvey Alter 1963 - discovery of the Australia antigen (hepatitis B surface antigen) Maurice Hilleman 1981 - first commercial vaccination against hepatitis B The Steam Age Charles Chamberland and Louis Pasteur 1879 - invention of the autoclave = effective method to kill microorganisms than using chemicals Ernst von Bergmann & assist. Schimmelbusch 1885 - began steam sterilization of surgical dressings 1890s - steam sterilizers is used in American hospitals American Sterilizer Company 1933 - introduce the first machine using temperature indicators, rather than just pressure = improving the control and accuracy of the process - Perkins described it as the ‘modern era of sterilization’ mid-1950s onwards - Low cost of automatic autoclaves = affordable and practical for general dental practice late 1950s - Supports autoclaves to reduce the risk of spreading hepatitis B - multiple cases of hepatitis transmission due to dental care Mid-1980s - boiling instruments in water = popular method for reprocessing instruments in UK Spaulding 1957 - surgical and medical instruments be reprocessed based on the risk of associated infection, based on knowledge about microbiology - Critical - within body cavities - Semi-critical - mucous membranes or non-intact skin - Non-critical - only touch intact skin - largely used in dentistry - Problems = pathogens escapes eradication if cleaned before sanitation 1950s - UK hospitals centralized sterilization services to achieve a standard of reprocessing - better maintenance of equipment and well-trained staff - mid-1960s advocates does the same for general dental practice HIV/AIDS and a New Era of Infection Control World Health Organization 1980 - Smallpox is eradicated - homosexual men in USA develop infections and cancers (Pneumocystis carinii & Kaposi’s sarcoma) - beginning of acquired immune deficiency syndrome (AIDS) epidemic 1984 - France & USA identified AIDS was due to a virus, human immunodeficiency virus (HIV) USA 1960s - hospitals for infectious diseases had been replaced by isolating patients in wards within general hospitals Centers for Disease Control and Prevention (CDC) 1970 - how to manage infectious patients based on epidemiologic risk factors, revised in 1975, including blood precautions 1983 guidance - About the emergence of AIDS - management of patients’ blood and body fluids - use of personal protective equipment (gloves and masks) - Problems: management of patients who were ONLY infected and ignored those in the population who were yet to be diagnosed 1985 guidance (universal precautions) - all blood and some body fluids should be considered infected - GOV, WHO, and the public response = societies can respond to infectious disease - early years of the AIDS epidemic fail to manage because of political ideology and values - media created fear and spread misinformation - Public health was wasteful by not specifically targeting those at greater risk - force dentists to look at their infection control measures, with universal precautions David Acer 1990 - died of AIDS-related illness - American dentist - six of his patients had contracted HIV from him - unclear how this happened - Now, no other known cases of patients with HIV from an infected member of the dental team 1996 - CDC replaced universal precautions in standard precautions 2003 - CDC issued guidelines, a tailored version of standard precautions, for dental setting Prions Stanley Prusiner 1982 - Introduced prions, proteinaceous infectious particles - Nobel Prize for Medicine because of his research 1984 - first case of bovine spongiform encephalitis (BSE), a prion-mediated disease in cows in UK 1988 - 600 cases of BSE - disease spread in cows = use of recycled animal protein in ruminant feed, following an initial sporadic case Lord Phillips - Revealed that British government is more concerned to BSE impacts to beef industry than humans (assuming that this type of disease did not cross species) Creutzfeldt-Jakob disease (CJD) 1992 - first dairy farmer in the UK died of this disease - 1995 - 4 deaths, the end of 1995, 10 cases of young people March 1996 - Variant CJD (vCJD) is developed by eating beef contaminated with BSE - transmission via the oral route 2016 - 178 cases vCJD in UK - major paradigm shift in dental infection control in the UK 2009 - Department of Health issued guidance referred as ‘HTM 01-05’ - greater emphasis on single-use instruments and pre-sterilisation cleaning - identified pulpal tissue as a possible source of infected tissue - mandatory single patient use endodontic instruments Learn from the Past - knowledge we have garnered on infection control must be shared and taught to those in the profession if we are to provide a global effort in delivering the safest care we can. THE MICROBIOLOGY AND PATHOLOGY 2 OF INFECTION CONTROL IN DENTISTRY Microorganisms, bacteria, viruses, fungi - ubiquitous, widespread in the environment, where we live, work and in and on our bodies. human body - 1014 cells - 10% are mammalian, remainder are microbial - small proportions = parasitic (pathological changes to make a disease) Virulence - extent or severity of disease, varies from microbe to microbe Pathogenicity - ability of a microbe to cause disease Infectious disease - cause damage to host, spreads to new hosts by shedding = leads to cross infection in medical/dental environment infectious dose - number of microbes required to infect an individual, vary from species to species risks of the transmission of microbes in dental environment will NOT only depend on the pathogenicity but its ability to survive in the environment Spores (survives >100C) - Bacteria produces this to protect them from heat, desiccation, lack of nutrients and chemicals - to survive in this state of inertia for a very long time = decades - able to revert to a vegetative state = multiply rapidly and cause disease - analogous to plants that produce seeds, they germinate = flowers/vegetables once again - Clostridium tetani, the cause of tetanus - better to use steam sterilizer because of high temperature steam than boiling for dental instruments Some bacteria - Has cell wall, dense and impenetrable, survive even with chemicals - survive outside of the host (dust), for several months - Mycobacterium tuberculosis, the cause of tuberculosis in man Most viruses survive poorly outside the host and have a short viability period unless protected by organic soil like blood or saliva. For instance, hepatitis B viral particles can survive for minutes outside the host, but can remain infectious for up to a week in dried blood. The risk of microbe transmission is influenced by the microbe's survival ability and its transmission route. Some microbes may spread through direct contact with another person infected or asymptomatically carrying and shedding the infectious agent. This can occur between the operator and the patient. Reducing this risk can be achieved by using personal protective equipment like clinical gloves. Infections can be transmitted through indirect routes like aerosols, created either directly by sneezing or indirectly by dental equipment like air rotors or mechanical scalers. These high-energy fine sprays pick up microbes from the patient's oral tissues and distribute them into the environment. Dental equipment or work surfaces, known as fomites, can be a source of infection transmission. Microbes have poor adherence to surfaces made of stainless steel or smooth plastic, but their ability to adhere is enhanced when contaminated with organic materials like blood or saliva. These organic materials can provide nutrients for bacteria, allowing them to multiply rapidly and colonize the environment. The initial level of contamination may have been low, but a delay in cleaning has led to an increase in bacteria, thereby exceeding the transmission threshold. Therefore, it is crucial to regularly clean all surfaces with a risk of contamination, particularly before and between patient treatment episodes, as a central plank of good infection control. Motile bacteria can spread contamination to adjacent areas in moist environments, making it crucial to dry surfaces after cleaning with liquids and avoid leaving them moist. It's also advisable to clean a wider area to ensure a margin of safety around contaminated areas. Therefore, it's essential to ensure surfaces are dry and not left moist. Most pathogenic bacteria cause the signs and symptoms of disease by the action of toxins on the host’s tissues. Exotoxins, produced by bacteria's metabolic processes, are proteins that can have various effects on the host's health. Some exotoxins can be cardiotoxic, haemolytic, or neurotoxic, causing damage to the heart, red blood cells, and nervous system. They are often strongly antigenic, stimulating the immune system to produce antibodies. This can lead to the development of vaccines aimed at the bacteria's toxins, preventing infection effects. For example, in tetanus and diphtheria, individuals are given doses of toxoid, which are chemically similar to the toxin but without toxic effects. This stimulates the immune system to produce antibodies, inactivating the toxin and preventing infection. Exotoxins are usually destroyed or inactivated by heat, making decontamination processes involving heat more effective in removing these substances from the clinical environment. Endotoxins, which are not secreted by bacteria but are found in the cell wall of certain types of bacteria, are heat-stable substances that are not released into the environment until the cell dies and breaks down. They are typically present in low levels in the body and are found in the gut and mouth as a product of the life and death of bacteria. At higher levels, endotoxins can cause effects such as raised temperatures (pyrexia), general unwellness, and impede wound healing. If released into the bloodstream in large amounts, it can cause toxic shock and lead to death. Raised and significant levels of endotoxin can be found in the water reservoirs of surgery autoclaves, where the water is allowed to be recycled repeatedly. The water is contaminated by environmental bacteria and multiplies in warm conditions, leading to the use of steam in the autoclave chamber. The bacteria in the water are destroyed, releasing endotoxin, which is then returned to the reservoir upon condensation. If this continues repeatedly, the accumulation of endotoxin may reach significant levels, potentially coating dental instruments with endotoxin, which could have adverse effects on patients. To mitigate this issue, it is recommended to discard the water in the autoclave reservoir at the end of each working day and refill it with fresh water at the beginning of the next working day. Using separate clean and used water reservoirs can also reduce the risk of recirculating endotoxins. Viruses are strict parasites that rely on the host's cells for survival. They attach to specific sites on the cell's surface and gain entry. Once inside, the virus 'highjacks' the cell's genetic material, corrupting its reproductive mechanisms. Instead of producing further copies of itself, the cell is reprogrammed to produce copies of the virus. Eventually, the cell is so full of copied viruses that it bursts open, releasing large numbers of viruses that can infect further cells in the host or be shed from the host, infecting more individuals. This process results in widespread destruction of host tissues, causing the disease's symptoms. Fungi like Aspergillus sp. can cause disease through toxins produced in food, which are then ingested by humans. Candida albicans, a single-celled fungus, can invade damaged oral tissues, particularly those depleted by antibiotics. Normally part of a balanced mixed population, Candida albicans can become the dominant species once other microbes are destroyed, making it an opportunistic pathogen. This can lead to the spread of diseases in oral tissues. Infection of a host usually leads to an immune response producing antibodies against the invading microorganisms. However, this defense mechanism may not always lead to the eradication of the microbes, causing the infection to persist or worsen. In some infections, the host's immune response is responsible for most tissue damage, such as tuberculosis and group A streptococcal sore throat. This is because antibodies formed against the streptococcus cell wall cross-react with the patient's heart muscle or valves, causing rheumatic fever. Medicine uses the immune response to prevent infectious diseases through vaccination. This involves using strains of microbes that resemble disease-causing microbes but are not capable of causing the disease. When injected into the host, these strains stimulate antibody production, preventing infection by pathogenic strains. Passive immunization involves antibodies harvested from recovered hosts given to people exposed to pathogenic microbes, such as hepatitis B. Vaccination may not always be effective in preventing disease due to the rapid microbial evolution. Successful microbes can multiply every 20 minutes, evolving at a rate half a million times faster than a human in 20 years. This means that effective vaccines may become ineffective quickly and may need to be redeveloped to address microbial changes, such as in the case of influenza. Some Examples of Infections that Could Be Transmitted in the Dental Environment Blood-Borne Viruses Hepatitis B - Found in blood of individuals infected with the virus - very low infectious dose - Has viral particles transmitting infection = 1 picolitre (10−12 L) of infected blood - readily transmitted to individuals with exposure to contaminated blood or saliva - 257 million are infected worldwide, nearly a million deaths a year worldwide - Chronic infection are 5% of those infected (death from cirrhosis or liver cancer) - Western Pacific and African regions has 6% infected - Europe has 1.7% infected - America has 0.7% infected - vaccination is available and will provide good protection in about 95% of individuals Hepatitis C - Found in blood of individuals infected with the virus - very low infectious dose - Has viral particles transmitting infection = 10 picolitre (10−12 L) of infected blood - readily transmitted to individuals with exposure to contaminated blood or saliva - 71 million chronically infected worldwide - 60–80% develops chronic infection, 30% develops cirrhosis or hepatocellular carcinoma (liver cancer) - no vaccine, but has antiviral drugs with a high success rate in curing the disease once it has been diagnosed - often asymptomatic for many years, diagnosis is until late stages and liver failure occurs HIV (Human immunodeficiency virus) - Found in the blood of infected individuals - less infectious than the hepatitis viruses - few cases is spread in the medical/dental environment - 25 million has HIV - treatments are available to control HIV infection - Untreated cases develops AIDS (acquired immune deficiency syndrome) - cause of death for patients with AIDS is tuberculosis Other Viruses: Influenza and Other Respiratory Viruses Respiratory viruses - Spread in winter months - aerosol transmission by coughing, sneezing, generated in dental practice - fairly minor, but in elderly or frail people = life-threatening influenza infection - cause 30,000 excess deaths per annum Norovirus - enteric virus, causes acute diarrhea and vomiting - Extremely infectious, with large outbreaks of illness - infectious dose is 10–100 viral particles - 685 million cases, winter months - Cause hospital ward closures if patients and staff are infected - affects the delivery of healthcare - relatively minor to healthy individuals - Transmits person to person, food produced or environmental contamination by infected person - Control of outbreaks is by adoption of high standards of hand hygiene - Survival of the virus can take several weeks Mumps - Infection in salivary glands, danger to dental practices via saliva - minor disease of childhood - Adults may cause morbidity (15% develop meningitis) - Controlled by vaccination using a combined vaccine, MMR (measles, mumps and rubella) - Problem: combined vaccine drops in uptake of the vaccine = re-emergence of disease Ebola Virus - caused by hemorrhagic virus, extremely infectiou - very high average mortality rate of 50%, 25–90%, in previous outbreaks - occur by human to animals carrying the disease, then spreads by human to human contact - spreads by contact with bodily fluids from infected persons - Occurred in small clusters in rural areas in West Africa - occurred in healthcare workers outside of West Africa by contact with travelers - Increased urbanization gives bigger risk of contact and causes big outbreaks of the disease - cross infection could occur in a dental environment Bacterial Infections Tuberculosis - Bacterial infection, Mycobacterium tuberculosis, a pulmonary (lung infection) - found in sputum of infected individual, contaminate the mouth - world’s most common infectious disease (1.7 billion) - acquiring resistance to the drugs commonly used to treat the disease - bacterium survive in the environment for months - healthcare has more risk of tuberculosis than general public - dental team are vaccinated, BCG vaccination Neisseria meningitidis - known as meningococcus - cause bacterial meningitis with significant mortality and morbidity rates for youngsters - found in the upper respiratory tract of asymptomatic carriers. - 10% adults, 25% of teenagers are carriers - risk of transmission in the dental environment Bordetella pertussis - whooping cough - found in the mouth and upper respiratory tract - cause severe disease in children and adults - re-vaccination of adults in antenatal clinics is used to reduce the spread to newborns THE REGULATION OF INFECTION CONTROL Safety for Both Patients and Staff Dentists and dental healthcare workers have professional, ethical, and legal obligations to meet, as well as business owners' obligations to their staff, patients, and the public. If a dental healthcare worker has concerns about infection control standards in their workplace, they should raise them with the person responsible for setting the standards. If no response is received, they may need to raise concerns with local or national regulators of infection control or professional standards. It is crucial to address issues that may negatively impact the health and wellbeing of those in an unsafe environment. Regulation Governments regulate dentistry to protect the public, setting laws and regulations. Guidelines provide technical details for compliance and understanding of these laws. Following these guidelines ensures the dental team meets their legal requirements, ensuring they adhere to the necessary technical details. Dental practices and third-party providers may have contracts specifying the following of set guidelines as a condition of their services. If a dentist fails to comply, they must provide reasons and justify their actions, which could lead to public criticism or prosecution, potentially affecting their professional reputation. Standards The CDC's infection control guidelines, which began in the 1970s and 1980s, were influenced by hepatitis and HIV/AIDS. The adoption of universal precautions in the mid-1980s led to a significant re-evaluation of infection control in dentistry. Standard precautions (1996) now form the backbone of all global infection control guidelines and are endorsed by the FDI World Dental Federation. Standards are agreed-upon criteria for products or processes in a discipline, set by national, regional, and worldwide bodies. They guide infection control aspects. Adhering to these standards and purchasing equipment that meets them ensures the dental team meets their obligations, boosting confidence in their performance. Minimum acceptable practice, or essential practice, sets a baseline for infection control, ensuring safety and effectiveness. Good practice focuses on achieving goals based on evidence-based research and expert opinion, and can be applied to infection control. Best practice outlines the superior way to achieve these goals. Quality assurance in infection control aims to maintain quality at all stages of the process. Infection control can be confusing due to the distinction between essential, good, and best practices. It's challenging to reconcile measures beyond essential practice, as infection control's primary purpose is to protect people. Transmission-based precautions identify patients with acutely ill, easily transmitted infections, and suggest rescheduling for care when they recover or refer them for specialized care. However, the ethical question arises regarding the risks people face when best practice is not achieved, and how to determine acceptable practices within the context of dental care practice, funding, and resource availability. Infection control is a dynamic discipline that evolves with research and new technologies, offering improvements in aspects that remain valid while maintaining minimum standards. However, these standards can also change. Infection control must be practical and economically viable, with the availability of resources, particularly money, playing a significant role in determining achievable goals. Infection control is a risk management exercise involving risk assessments based on scientific principles and expert opinion. It's important to acknowledge that we don't know the likelihood of certain risks or the extent of interventions reducing them. Dental nosocomial infections are likely under-reported, but following infection control procedures can reduce transmission risk. Cost as a Barrier to Infection Control Cost is a crucial factor in infection control, especially in dentistry where single-use re-usable instruments like dental handpieces are not financially viable. While cost can be a barrier, it should not be used as an excuse for poor infection control. It is reasonable to expect a level of financial commitment based on resource availability within the country where dentistry is practiced, as healthcare-acquired infections are a global problem and resources are not shared equally. Many countries lack the financial resources and infrastructure of others, requiring national and local dental organizations to set standards for their members. International efforts, such as the WHO/UNICEF WASH strategy, may be needed to raise standards, as it focuses on sanitation and hygiene in healthcare needs in areas where help is needed. The Environmental Impact of Infection Control Sustainability in healthcare, including dentistry, is a global imperative due to legal obligations to address climate change and greenhouse gas emissions. This is achieved through optimized resource management and environmental improvements. Improving infection control can improve sustainability, but challenges remain to be overcome. Infection control's environmental impact includes energy, toxic chemicals, and waste. Electricity and gas use contribute 15% of dental care's carbon footprint. Reducing this includes turning off autoclaves, using hot water, and using reverse osmosis-generated water instead of on-site distillation. The hierarchy of waste management prioritizes recycling and reducing dental waste. Separating instrument wrapping for recycling prevents contamination and incineration. Technological advancements are reducing dental waste by converting radiographic waste chemicals and film lead to digital radiography. Intraoral scanners eliminate waste generation from impression materials and gypsum, which emits toxic hydrogen sulfide gas when mixed with organic waste. Single-use plastics pose a significant environmental concern as they do not biodegrade and persist in the environment when thrown away. They are crucial for infection control as they cannot be reliably cleaned. Lowering infection control standards is not appropriate. Improvements in materials, packaging, and manufacturing methods can help. For instance, paper-based suction tips and recycled plastic tips can be used. However, it is currently not possible to recycle contaminated single-use plastic items. Disposable plastic barriers in surgeries may be unnecessary. Waste facilities can recycle medical waste as a flock, which can be used as fuel, and ash recovered from incinerated waste can be used as aggregate for asphalt roads. Australia and New Zealand are reducing the use of disinfectant chemicals in dentistry by using detergents for hard surfaces. Countries signatories to the Minamata Convention are reducing their use of dental amalgam. Amalgam separators in dental suction systems help reduce waste that can contaminate waterways. Waste contractors should separate extracted teeth containing amalgam from other clinical waste. These efforts aim to reduce toxins released into the environment. Case Studies Case Study: The Role of Resources in Shaping Standards The dentistry and patients in England and Scotland are similar, likely due to the same infection control risks. However, they have different infection control guidelines and essential standards. In Scotland, thermal washer disinfectors are considered essential practice, while in England, it is best practice. This difference is partly due to a smaller number of dental practices in Scotland and government grants for some practices that meet this standard. Additionally, the lack of government resources for state-funded dentistry in England may also contribute to this difference. Case Study: The Gap Between Essential Practice and Best Practice Dental practices began processing handpieces in an autoclave in the mid-1990s due to public scrutiny and fear of HIV transmission. The World Health Organization (WHO) now considers handpieces reprocessed, including in an autoclave, after use. Non-vacuum autoclave handpieces may not be sterile, so vacuum autoclaves are recommended for sterility assurance. Although there is a significant difference in running costs between the two types and limited evidence supporting the risk to patients, vacuum autoclaves are unlikely to become essential for all handpieces worldwide. In some parts of the world, such as Australia, surgical handpieces must be reprocessed in a vacuum autoclave. HAND HYGIENE AND PERSONAL PROTECTION Hands Semmelweis highlighted the significance of hand hygiene in 1847 and remains the most crucial intervention in infection control. Hands are the primary source of transmission of diseases due to the presence of pathogens in the flora on our hands, microbes attached to the skin, contact with others, pets, and surfaces like door handles. These pathogens can be passed onto patients or self-inoculate themselves. Hand hygiene aims to remove these harmful microorganisms and prevent their spread. Hand hygiene in healthcare, particularly dentistry, is often subpar. To improve compliance, the infection control lead should establish a practice hand hygiene policy, provide regular staff training, display hand cleaning posters, and ensure suitable facilities. Constant reminders and feedback are crucial for maintaining good hand hygiene in the healthcare sector. Soap and Water Hands can be cleaned using soap and water or an alcohol-based hand rub. The temperature of the water should be comfortable to avoid burning and rushing, while also reducing energy consumption. Liquid soap is recommended over traditional bars as they can act as a fomite for microbes. After washing, hands should be dried to prevent bacteria recolonization. Moist gloved hands are more prone to irritation. Disposable paper towels are recommended for dentistry as hand dryers can be noisy and potentially blow droplets containing unwashed flora into the air. This ensures a clean and healthy environment for patients. Alcohol Rub Alcohol hand rubs are recommended for routine hand hygiene due to their ease of use, effectiveness in promoting compliance, and broad antimicrobial activity. They are also quick evaporating, leaving hands dry before gloves are worn, and reducing paper waste. This is particularly beneficial when handwashing alone is not sufficient. Hand rubs vary in alcohol content and additives, impacting their drying time and comfort. A minimum of 60% alcohol is recommended, with humectants like glycerol and emollients for skin irritation. For optimal effectiveness, rubs should be used for 20-30 seconds, ensuring they don't evaporate quickly. Thickeners can moderate evaporation time. When to Wash and When to Rub Handwashing hands with soap and water is essential, especially after contact with body fluids and using the toilet. Repeated hand washing can dry out skin, leading to dermatitis. Alcohol hand rubs reduce irritant dermatitis but cannot clean dirt off hands and don't kill all microorganisms. Alcohol attacks the lipid envelopes of viruses, but certain gastric viruses like Norovirus don't have this cellular feature, making it less effective. Therefore, washing hands with soap and water is preferable after using the toilet. Moisturizers, used at the end of a session, help reduce hand drying by acting as a barrier, but should not be used before gloves to maintain the integrity of the glove material. Soap, alcohol rub, and moisturizer should be stored in single-use dispensers or cartridges to prevent microorganism accumulation. Purchase alcohol rub conforming to EN 12791 for safety. Store alcohol hand rub safely away from ignition points and avoid placing dispensers above carpet or near fire exits in non-clinical areas. Personal Protective Equipment (PPE) The dental team should expect safe working conditions and prioritize risk management to eliminate or reduce safety risks. A contemporary method for assessing risk management is a hierarchy of hazard controls, with eliminating safety risks being the most desirable control measure, although this may not always be feasible. The dental team faces potential injury from infections, mainly those carried by patients. They are exposed to numerous pathogens through blood and saliva, and their daily tasks, such as placing fingers in patients' mouths, using sharp instruments, and generating aerosols, increase the risk of infection. Dental care workers are particularly vulnerable to pathogens, particularly in the face and hands. To reduce the risk of infection, personal protective equipment (PPE) is used as a physical barrier. PPE is regulated and mandatory in many countries, and employers are required to supply it. While PPE is essential for risk management, it is not the most effective way to control risks, so users should be aware of its limitations. Eyes Dental procedures expose eyes to infection and mechanical and chemical injury, which can be spread through blood and saliva splashes, dispersion of tooth and dental materials, and splashes of chemicals and disinfectants. Eye injury is a potential hazard during treatment and decontamination. Eyewear should conform to regional standards, such as ANSI Z87.1-2003 in the USA, BS EN166:2002 in Europe, AS/NZS 1337.1 in Australia and New Zealand, and SANS404 in South Africa. First aid protocols should be in place in case of eye contamination or injury, and material safety data sheets can help manage chemical splashes. An eye wash kit or station is crucial in dental practices, and staff should be aware of its location. Nose and Mouth Face masks protect the nose and mouth from dental procedures' splatter and aerosols. They may also protect patients from the wearer, but the evidence is weak. Wearing a mask even when using a face shield provides optimal protection against upward splatter that may go under the shield. Face masks have limitations and should be used properly for their effectiveness. They are single-use and should be disposed of after each patient. Complications include touch-ups, pulling down, and prolonged wear. Moisture wicking can cause the mask to collapse, making it a poor barrier for contaminants to come into contact with the wearer. Effective communication in dentistry is crucial, but wearing a face mask can hinder it. Instead of pulling the mask over the chin, remove it with dirty gloves and discuss with the patient before putting on a new mask. However, incorrect mask wearing has become normalized in the dental press. Routine dental care face masks may not filter out smaller particles causing respiratory infections like tuberculosis or influenza. In clinical settings, FFP3 class respirator masks are recommended for acute respiratory infections treatment. Public health authorities recommend this type for clinical staff during influenza epidemics, but it's not covered in this guide. Gloves William Halsted, a pioneering surgeon, commissioned the Goodyear Rubber Company to create the first pair of rubber gloves in 1890. Inspired by Lister, Halstead introduced aseptic surgical techniques, but his colleague Joseph Bloodgood first started wearing gloves for his operations. In 1987, universal precautions were introduced, and examination gloves are now mandatory for dental care. They protect the wearer from pathogens and harmful chemicals, and indirectly protect the patient from infections. Gloves are used in oral and maxillofacial surgery for deep wounds, but not for routine dental care. Studies show no difference in post-operative complications between sterile and non-sterile gloves for nonsurgical tooth extraction. Non-sterile gloves have a low bacterial load, likely not causing wound site infections. To prevent contamination, adherence to hand hygiene and storage of gloves in a way that prevents aerosols from settling on them are essential. Wall-mounted glove dispensers can help keep work surfaces uncluttered. Double gloving, a practice of wearing two pairs of gloves simultaneously, originated in response to the fear of HIV in the 1990s. While it is useful for exposure-prone surgical procedures like orthopedic surgery, it is unnecessary for routine dental care. Treating patients solely because they are HIV positive is stigmatizing and discriminatory. Some countries require HIV-positive dentists to double glove, but there is no evidence supporting this requirement. Examination gloves are made from latex, nitrile, and vinyl materials, with latex being the most popular due to its lower cost, elasticity, and durability. However, latex rubber gloves can cause allergies, potentially leading to life-threatening anaphylactic reactions. Powder donning agents may absorb latex proteins, so it's important to avoid them. Powder-free gloves prevent the creation of an aerosol of latex proteins, which can be inhaled by staff or patients or transferred beyond the surgery. Latex and non-latex gloves often cause type IV delayed hypersensitivity contact dermatitis reactions due to accelerators, chemicals used in glove manufacturing. Some patients have allergies to the dye used to color nitrile gloves. While manufacturing methods aim to reduce allergens, some dental practices opt to make them latex-free, following the risk hierarchy principle of substitution. If a safer alternative exists, it is used. Elastomeric impression materials mixed by hand can be inhibited by latex gloves, nitrile gloves, and donning agents due to the reaction of sulfur in latex gloves with the chloroplatinic acid catalyst, making the impression unreliable. Wearing nitrile or vinyl gloves is recommended. Gloves offer protective barrier benefits but can also cause skin irritation due to sweat accumulation and frequent hand hygiene. Long-term use can increase microporosities, reducing their protective effect. Therefore, gloves should be changed during lengthy procedures to avoid irritation. Gloves are a single-use item that should be disposed of properly. However, they do not eliminate the need for hand hygiene. Healthcare workers often misuse gloves, keeping them on and continuing with tasks that should have required hand hygiene. This can spread infection. It is crucial to limit glove use to clinical wear and remove them before touching clinical records or pens. It is also important to avoid walking out of the treatment area while wearing gloves. Using gloves thoughtfully can help improve sustainability by ensuring everything is in place before work, such as materials being out of drawers and radiographs and charts visible, reducing glove changes during patient visits. Examination gloves are not sufficient protection against sharps and puncture wounds when instruments are cleaned during the reprocessing cycle. Heavy-duty gloves are recommended, especially for manual cleaning, as it increases the risk of injury to those handling the instruments. They should be washed after use and left to dry. If damaged, they should be disposed of, and it is recommended to replace them weekly. Uniform and Aprons Uniforms should not be considered PPE but should be worn separately from regular clothes to prevent contamination. High-temperature-washable fabrics are recommended. While home cleaning isn't ineffective, it's advisable to carry uniforms in a plastic bag and clean them separately. If space permits, a dedicated washing machine within the practice could be considered for laundering uniforms. Considering a dedicated machine within the practice could further reduce infection risks. Uniforms should end at the elbows for good hand hygiene, but this may be culturally or religiously sensitive. A study found no difference in hand hygiene efficacy based on bare or bare elbows. In dentistry, wet sleeves can cause bacterial growth due to fabric taking up water. Full or three-quarter sleeves can be used to address this issue, or single-use disposable sleeves can be used for treatment. Clinical procedures and decontaminating instruments increase the risk of body fluid splashes. Disposable plastic aprons and sterile gloves are recommended for minor oral surgery, excluding nonsurgical extractions. These aprons protect against contamination and reduce the chance of microorganism contamination. Wall-mounted apron dispensers are available, and aprons should only be worn for a single patient. The cuffs are covered by sterile gloves. Treatment Considerations To reduce aerosol exposure in patient treatment, use high-volume evacuation suction and rubber dams, ensure good ventilation, and use chlorhexidine mouthwash before using ultrasonic scalers. Discuss the use of chlorhexidine with patients following documented cases of fatal allergic reactions in dental practices. Proper ventilation and airflow are essential for effective treatment. Putting on and taking off PPE The order of putting on and taking off PPE is crucial, with clean gloves being put on last after hand hygiene to minimize contamination. When removing gloves, they should be removed first, while other barriers should be removed safely to avoid inadvertent contamination. Putting on PPE 1. Where indicated, put on single use apron first. 2. Fit face mask. 3. Fit eye protection. 4. Undertake hand hygiene. 5. Put on gloves. Removing PPE 1. Remove gloves by pulling them inside out. If the hands become contaminated at this point, they should be washed. 2. If worn, remove the apron by breaking at the back of the neck and folding it inwards by gathering it on the clean side that rests against the body. 3. Face masks are either unhooked from the ears or the ties broken and the mask removed away from the face whilst holding the outer edge where least likely to be contaminated. 4. Eye protection is then removed. 5. All disposable items should be placed in the appropriate waste stream. 6. Hand hygiene is performed 7. Face shields and safety glasses will need to be cleaned or disposed of where damaged. ESSENTIALS OF INFECTION CONTROL Dentists and dental team members are exposed to various infectious microorganisms in their clinical working environment, which can lead to cross-infection. To prevent and control infection in dentistry, protocols and procedures are implemented to reduce the risk of cross-infection, ensuring a safe environment for patients and staff. Employers in the UK are legally obligated under the Health and Safety at Work Act 1974 to ensure employees are adequately trained and proficient in safety procedures. They are also required by the Control of Substances Hazardous to Health (COSHH) Regulations 2002 to review every procedure involving contact with hazardous substances, including pathogenic microorganisms. Employers and employees are also legally responsible to prevent any avoidable risk to patients, contractors, and visitors on the premises. Management of cross-infection risks is crucial in dentistry, with infection control measures aimed at reducing the probability of infection transmission to an acceptable level, typically measured against the expected infection rate in the local population. RELATIVE RISK AND RISK PERCEPTION The dental profession and public's perception of risk can vary significantly, impacting the safety of dental treatment. This is particularly evident following sensational media reports of 'dirty dentists' who fail to sterilize instruments or wash their hands. Personal-controlled risks, such as driving a car, are often perceived as more acceptable than those involving airplanes or trains. Unseen risks, such as infection-related infections like AIDS or MRSA, are most alarming to the profession and the public. These risks can be clinical, environmental, financial, economic, or political, and can affect the public's perception and reputation of the dentist or team. What makes risks significant (risks significant and worthy of concern) - Potential for actual injury to patients or staff - Significant occupational health and safety hazard - The possibility of erosion of reputation or public confidence - Potential for litigation - Minor incidents which occur in clusters and may represent trends The term hazard is crucial in infection control, referring to situations or substances, including microorganisms, that can cause harm. Risk assessment should consider the likelihood and severity of a hazard's impact on patients or dental staff, as well as the potential harm caused. RISK ASSESSMENT AND THE MANAGEMENT DECISION‐MAKING PROCESS Dental practice managers are responsible for managing risk, as mandated by the Management of Health and Safety at Work Regulations 1999. This includes conducting risk assessments as part of a risk management strategy, including infection control. Risk management involves identification, assessment and analysis of risks and the implementation of risk control procedures designed to eliminate or reduce the risk. Dental risk control relies on a single-tier approach, known as Standard Infection Control Precautions (SICPs), which treat all body fluids, except sweat, as potential sources of infection. SICPs involve measures and procedures to prevent exposure of staff or patients to infected body fluids and secretions. Dental healthcare workers use personal barriers and safe behaviors to prevent the exchange of blood, saliva, and respiratory secretions between patient and operator. Healthcare professionals and organizations should consider potential risks in their decisions, aiming to achieve an optimal balance of risk, benefit, and cost. Proper risk assessment helps set priorities and improve decision-making. Dental teams can reduce potential risks and identify opportunities for improvement by systematically identifying, assessing, learning from, and managing all incidents, ultimately leading to better patient care. HOW TO PERFORM A RISK ASSESSMENT IN A DENTAL PRACTICE A risk assessment in dental practice involves the following steps. 1. Identify the hazards. 2. Decide who might be harmed, and how. 3. Evaluate the risks arising from the hazards and decide whether existing precautions are adequate or whether more needs to be done. 4. Record your findings, focusing on the controls. 5. Review your assessment periodically and revise it if necessary. Stage 1: Identify the hazards - Divide your work into manageable categories. - Concentrate on significant hazards, which could result in serious harm or affect several people. - Ask your employees for their views; involve the whole dental team. - Separate activities into operational stages to ensure that there are no hidden hazards. - Make use of manufacturers’ data sheets to help you spot hazards and put risks in their true perspective. - Review past accidents and ill health records. Stage 2: Who might be harmed? - Identify all members of staff at risk from the significant hazard. - Do not forget people who only come into contact with the hazard infrequently, e.g. maintenance contractors, visitors, general public and people sharing your workplace. - Highlight those persons particularly at risk who may be more vulnerable, e.g. trainees and students, pregnant women, immunocompromised patients or staff, people with disabilities, inexperienced or temporary workers and lone workers. Stage 3: Evaluate the level of risk - The aim is to eliminate or reduce all risks to a low level. - For each significant hazard, determine whether the remaining risk, after all precautions have been taken, is high, medium or low. - Concentrate on the greatest risks first. - Examine how work is actually carried out and identify failures to follow procedures or practices. - Need to comply with legal requirements and standards. - The law says that you must do what is reasonably practical to keep your workplace safe. A numerical evaluation of risk can be made to help prioritize the need for action and allow comparison of relative risk. Risk is equal to hazard severity multiplied by likelihood of occurrence. Assign a score of 1–5 for each, with a total value of 16–25 equating to high risk, 9–15 to medium risk and >8 to low risk Stage 4: Record your findings - Record the significant findings of your risk assessment and include significant hazards and important conclusions. Look at how current controls and protocols could be modified to reduce the risk further. Recording can be done simply on a spreadsheet or chart. The most important outcome of any risk assessment is the control measures so focus your efforts on making sure that the control measures the dental practice employs to manage the hazards associated with cross‐infection and other aspects of health and safety are sensible and effective. Information to be recorded includes the following points. - Activities or work areas examined - Hazards identified - Persons exposed to the hazards - Evaluation of risks and their prioritization - Existing control measures and their effectiveness - What additional precautions are needed and who is to take action and when Stage 5: Review your assessment - Risk assessment is a continuing process and must be kept up to date to ensure that it takes into account new activities and hazards, changes in processes, methods of work and new employees. - You must document your findings but there is no need to show how you did your assessment, provided you can show that a proper check was made and you asked who might be affected, and that you dealt with all the obvious significant hazards, taking into account the number of people who could be involved, that the precautions taken are sensible and reasonable, and that the remaining risk is low. HIERARCHY OF RISK MANAGEMENT CONTROL After a risk assessment, a plan must be implemented to control the observed risk, prioritizing necessary controls and aiming to reduce risks to an acceptable level while complying with legal requirements. A reasonable time scale for completion and responsibility for taking necessary action should be established. There is a hierarchy of control options, which can be summarized as: - elimination (buy in services/goods) - substitution (use something less hazardous/risky) - enclosure (enclose to eliminate/control risks) - guarding/segregation (people/machines) - safe systems of work (reduce system to an acceptable level) - written procedures that are known and understood by those affected - adequate supervision - identification of training needs and implementation - information/instruction (signs, handouts, policies) - personal protective equipment (PPE). INFECTION CONTROL AND THE LAW Infection control laws can be derived from legal acts, orders from individual counties, or European Union directives. Regulations are laws approved by the national legislative body, such as the Health and Safety at Work Act 1974 in the UK and the Health and Social Care Act 2008 (Regulated Activities) Regulations 2014 in England. These laws govern infection control and cleanliness in dental surgery. The Health and Safety at Work Act and management regulations provide employers with the freedom to control risks they identify. However, some risks are so significant or costly that it is not appropriate for employers to regulate them. The Act and Regulations identify these risks and outline specific actions that must be taken, often being absolute, based on whether it is reasonably practicable. Approved codes of practice (ACOP) provide practical guidance on how to comply with regulations, such as what is reasonably practicable'. They can help employers understand what is required in specific circumstances, such as suitable and sufficient'. ACOPs have a special legal status, using a reverse burden of proof. If employers are prosecuted for a breach of health and safety law, and they are proven to have not followed the relevant provisions of the ACOP, they can be found at fault unless they demonstrate alternative compliance. LEGAL ACTS UNDER WHICH DENTAL PRACTICE IS CONDUCTED Health and Social Care Act 2008 (Regulated Activities) Regulations 2014 The Health and Social Care Act (HSCA) established the Care Quality Commission (CQC) in 2009 to regulate the quality of health and social care in England. Primary care dental services in England were required to register with the CQC as providers or managers from 1 April 2011. It is illegal for any primary care dental service to carry out regulated activities without registration. CQC inspections report on the safety, effectiveness, care, responsiveness, and well-led dental services in relation to a standard set of key lines of enquiry (KLOE), including cleanliness and infection control. The CQC benchmark for assessing cleanliness and infection control is the HSCA-Approved Code of Practice 2015, which comprises 10 criteria for delivering infection control and prevention across healthcare, including dentistry. Antimicrobial stewardship in dentistry The HSCA-ACOP's third criterion addresses antimicrobial stewardship and prescribing, reflecting the global rise in antimicrobial resistance and stagnation in antibiotic development. In the UK, 70% of dental prescribing is for antibiotics, with 50% of dentists overusing them or having poor prescribing practices. The criterion is included alongside infection control measures to address the issue, as research shows that 50% of dentists overuse antibiotics. Health and Safety at Work Act 1974 The Health and Safety at Work Act (HSWA) in the UK mandates a safe working environment, setting the standard for other health and safety regulations. Employers are obligated to ensure the health, safety, and welfare of their staff and the public at their workplace. The Management of Health and Safety at Work Regulations (MHSWR) 1999 clarified these obligations, placing the legal responsibility on employers. The MHSWR mandates employers to assess workplace risks and implement appropriate measures, including risk assessments. The HSWA is regularly updated. It is the duty of the employer to consult with staff on matters which may impact on their health and safety at work, including: - any change which may substantially affect their health and safety at work, e.g. in procedures, equipment or ways of working - the employer’s arrangements for getting competent people to help him/her satisfy health and safety laws - the information you have to be given on the likely risks and dangers arising from your work, measures to reduce or get rid of these risks and what you should do if you have to deal with a risk or danger - the planning of health and safety - the health and safety consequences of introducing new technology. The duties of employers under this law include: - making the workplace safe and without risks to health - ensuring plant and machinery are safe and that safe systems of work are set and followed - ensuring articles and substances are moved, stored and used safely - providing adequate welfare facilities - giving the information, instruction, training and supervision necessary for the health and safety of staff and the public. Control of Substances Hazardous to Health Regulations 2002 The law mandates employers to manage hazardous substance exposure to prevent health issues, protecting employees and others. Compliance with COSHH regulations is crucial for good management. It provides a step-by-step approach for employers and employees to assess risks, implement measures, and establish good working practices, ensuring a safe work environment. Note that hazardous substances include not only chemicals such as mercury, solvents and the materials used in dentistry, but also biological agents such as bacteria and other micro‐organisms. The Regulations mandate a COSHH risk assessment on all materials used in dental practice. If it's not possible to prevent exposure to hazardous substances, they must be controlled through appropriate measures. For dental team members treating individuals suspected of being infected with microorganisms, protective measures include adequate ventilation systems and the provision of personal protective equipment (PPE). Employers are required to provide PPE that protects against risks associated with the task. COSHH also requires employees to wear PPE provided by the employer, who should ensure that PPE and other control measures are implemented in the practice or dental hospital. Reporting of Injuries, Diseases and Dangerous Occurrences (RIDDOR) 2013 The Irish Workplace Injury and Diseases Regulation (RIDDOR) mandates employers, self-employed individuals, and those in control of work premises to report serious workplace accidents, occupational diseases, and dangerous occurrences to the Health and Safety Executive (HSE). In Northern Ireland, incidents should be reported to HSE NI, enabling the HSE and local authorities to identify risks and investigate serious accidents. You must report: - all deaths in the workplace - specified injuries and over‐seven‐day incapacitation of a worker which results in the employee or self‐employed person being away from work or unable to perform their normal work duties for more than seven consecutive days plus the day of the accident (includes weekends and rest days) - diagnosis of certain occupational diseases, where these are likely to have been caused or made worse by their work including, for example, Legionnaires’ disease, hepatitis B - non‐fatal accidents to non‐workers (e.g. members of the public), if they result in an injury and the person is taken directly from the scene of the acci- dent to hospital for treatment to that injury. The report must be submitted within 15 days of an accident, and workplace accidents over three days (but less than seven days) must be recorded in an accident book but not reported to the HSE. Dental surgery should encourage accident reporting and near misses. Pressure Systems Safety Regulations 2000 Pressure equipment failure can cause serious harm to people and property. Autoclaves, pressurized vessels, are subject to annual testing for safety and insurance purposes. The Pressure Systems Safety Regulations, enacted in 2000, cover the installation and use of steam sterilizers. Dental practices must obtain a written examination scheme from the manufacturer, supplier, or insurer before using the sterilizer. A certificate is issued as proof of each inspection, and the sterilizer logbook is maintained. Users and owners must demonstrate knowledge of safe operating limits, primarily pressures and temperatures, and that the systems are safe under those conditions. As a legal requirement, each sterilizer must have: - a written scheme of examination - a periodic examination of the pressure system and retention of the certificate - third party liability insurance that specifically covers risks associated with the operation of pressure vessels, e.g. sterilizers and compressors. Such risks may not be covered by the practice’s building insurance - a record of all repairs and maintenance of the pressure system. PUBLISHED STANDARDS AND GUIDANCE Infection control and prevention standards and guidance are established by various government agencies and public sources, including key UK agencies and equivalent organizations for Northern Ireland, Scotland, and Wales, and country-specific equivalent organizations where applicable. Policy The government's policy is dictated by strategic documents and is often implemented by special advisory bodies like the Advisory Committee on Dangerous Pathogens (ACDP). These bodies advise on hazards and risks to workers and others, including exposure to pathogens and risk assessment advice on transmissible spongiform encephalitis (TSEs). The Department of Health then cascades the strategy to local organizations like authorities and health boards, using health service circulars and newsletters from the Chief Dental Officer to communicate with dental professionals. Procedures Dental practice professionals receive guidance and recommendations on infection control procedures through various formats like health technical memoranda, health building notes, drug and device alerts, and drug safety updates. These provide essential information for maintaining good practice and communicating changes in practice after adverse incidents with equipment or medication. Drug and device alerts are often written in response to these incidents. Health Technical Memoranda HTM publications offer technical advice and guidance on healthcare topics, such as decontamination in primary care dental practices. HTM 01-05 provides in-depth guidance on the decontamination cycle, including choice, specification, purchase, installation, validation, testing, operation, and maintenance of ultrasonic baths, thermal washer disinfectors, and sterilizers, significantly impacting dental practice in the UK. Implementation HTM publications offer technical advice and guidance on healthcare topics, such as decontamination in primary care dental practices. HTM 01-05 provides in-depth guidance on the decontamination cycle, including choice, specification, purchase, installation, validation, testing, operation, and maintenance of ultrasonic baths, thermal washer disinfectors, and sterilizers, significantly impacting dental practice in the UK. TEAM APPROACH TO PREVENTION OF INFECTION A team is more than just a group of people working together; it has been defined as: - A small number of people with complementary skills who are committed to a common purpose, performance goals and approach for which they hold themselves mutually accountable. Infection control requires a team approach with complementary skills and a common purpose. Effective team functioning requires clear goals, good communication, fair leadership, and an open climate. This encourages staff to feel confident in treating patients with infectious diseases and express concerns, improving service delivery. Teamwork improves job satisfaction, increases the sense of being valued, and encourages collective responsibility for service delivery. A blame culture is avoided, fostering a respectful and open environment. Effective leadership is crucial in the dental team, and leaders must communicate the team's vision of excellence and communicate this to other members. This is achieved through adequate training in infection control and regular clinical management meetings. These meetings allow for communication and risk assessments, especially in the rapidly developing field of infection control. Regular structured team meetings are essential, especially in busy dental practices. Communication is also crucial for members to report accidents and share opinions, reservations, and fears regarding infection control policy and work conditions. It is essential not to discourage individuals from reporting accidents or incidents, as the perception of failure can discourage them from achieving excellence. It is useful to consider what the causes of human failure are, as human error is one of the most frequent reasons for breaches in infection control practice. Failure is usually caused by either: - errors in knowledge where the HCW did not know what they were supposed to do to, for example, the importance of safe disposal of sharps and the pre- vention of transmission of infection by aerosol in the clinic, or - errors in skills where the HCW did not have sufficient training to, for exam- ple, carry out procedures such as decontaminating an instrument or using a scalpel safely. Poor organization and management in dental surgery can lead to personal failure and errors. Reducing human error is crucial for good practice management and an effective team. Improving job design, ensuring everyone knows their duties and skills, introducing job rotation and enrichment, and enhancing training and multiskilling can help minimize errors. Encouraging staff participation in decision-making and making them feel valued members of the dental healthcare team can also reduce errors. If errors do occur, they can be quickly corrected and unlikely to reoccur. Overall, a well-organized and effective team can significantly reduce human error in dental surgery. COMMUNICABLE DISEASES IN THE DENTAL SURGERY HOW INFECTIONS ARE SPREAD Microorganisms need to attach to or penetrate the body's surfaces to establish themselves and cause infection. This association has evolved over millennia, making many species of bacteria colonizing the mouth and oral tissues unique to the human body. While intact skin protects the body from microbial invasion, mucosa-lined orifices are susceptible to infection entry. These sites are protected by secretions like saliva and tears, as well as cellular and antibody immunological defense mechanisms. However, mucosal surfaces and damaged skin remain weak links in our defenses, so we wear protective clothing like masks and goggles to protect our respiratory, lips, and mouth from infection. Most microbes do not cause infection in humans, but they live in harmony with our body and protect us by preventing colonization. Streptococcus sanguinis and cariogenic mutans streptococci compete for colonization in the mouth, which can delay dental caries. However, some commensal and harmless microbes can cause infection if the host's immune system is compromised by factors like age, diseases like diabetes or cystic fibrosis, or infections like HIV. These opportunistic pathogens require dental clinicians to be cautious when taking a patient's medical history, as they may be more susceptible to infection due to compromised immunity. Steps should be taken to protect these vulnerable patients and maintain their health. Breaking the chain of infection Pathogens, microorganisms that cause disease, require a means of transmission from host to host to disperse. In dental clinics, inherent infection risks can lead to disease transmission. Pathogens require a susceptible host, virulence factors to survive immune system challenges, and entry and exit methods. The 'chain of infection' consists of six components that lead to disease. Breaking these links can prevent further transmission and prevent disease. Vaccination and drug therapy protect the host, eradicate the source and reservoir of the infection, and treat the disease. Infection control and prevention measures can block transmission routes and prevent entry and exit portals. RESERVOIRS AND SOURCES OF INFECTION A patient attending for dental treatment can act as a source of infection. In an outbreak situation they are referred to as the index case. He or she may present with one of the following four stages of infection/colonization. - As a patient suffering from an acute infectious disease, for example influenza, measles, tuberculosis (TB). - As a patient in the prodromal stage of infection, when the patient is infectious but not showing clinical symptoms, for example mumps or measles. - As a patient in the convalescent or latent stage of infection, who continues to shed viruses in their secretions, for example herpes simplex virus (HSV), Ebola virus. - As an asymptomatic carrier of potential pathogens, for example Streptococcus pyogenes (sore throat), methicillin‐resistant Staphylococcus aureus (MRSA), Neisseria meningitidis (meningitis) and Haemophilus influenzae (bronchitis). Acute infections are highly infectious and release large numbers of microbes into the environment. Dentists must be willing to treat these patients urgently to ensure the safety of themselves, staff, and patients. Postponing elective dental treatment during the infective period can improve patient comfort and eliminate cross-infection risks. Dentists can also act as sources of infection, such as those suffering from respiratory or skin infections. They should seek advice from their GP on their fitness to work. Asymptomatic carriers of hepatitis B and C virus (HBV) and HCV infection are often unaware of their status and cannot be easily identified in the dental chair. Patients can be encouraged to reveal their carrier status through empathic questioning and appropriate questioning during medical history. Asymptomatic carriers pose serious risks for transmission of infection in dentistry, and universal precautions are applied to manage all patients and their body fluids as if they were potentially infectious for a blood-borne virus (BBV) as part of the dental practice's Standard Infection Control Precautions (SICPs). Healthcare-associated infections (HCAI) are infections acquired or emerge during treatment or inpatient stays, causing concern in medical and dental professions. They are considered HCAI if they first appear 48 hours or more after hospital admission or within 30 days after discharge. Prevalence rates vary but are around 6-10% in many countries, with urinary tract infections and pneumonia being the most prevalent. Outbreaks of MRSA, Clostridium difficile, and antibiotic multiresistant organizms are significant concerns on hospital wards. Both in- and outpatients can become colonized with these microbes for extended periods, potentially causing community spread. Dental teams must know how to prevent these microbes from spreading, using simple infection control protocols like hand hygiene and donning barriers. INFECTIOUS DISEASES BY ROUTE OF INFECTION IN DENTISTRY There are four main routes by which infection can be transmitted in a dental practice 1. Transmission by direct or indirect contact, for example touching a surface with contaminated hands. 2. Percutaneous (parenteral) transmission, such as sharps injuries. 3. Transmission via air‐borne route, for example aerosols generated by high‐speed handpieces and respiratory secretions. 4. Common vehicle spread, such as dental unit waterlines and plumbing. Understanding the transmission route of an infective agent helps choose the most effective measures to block cross-infection. Emerging infections, such as variant Creutzfeld-Jakob disease (vCJD), often pose challenges to existing Standard Precautions methods. Experimentation studies have shown that instrument sterilization in the UK has had to change in response to these challenges. Emerging infections require a dynamic and inventive approach to infection control to avoid being beaten by microbes. Therefore, a dynamic and inventive approach is necessary to combat these threats. Insect vectors like mosquitoes are a major route of transmission of diseases like malaria, dengue, chikungunya, West Nile, and Zika virus. These arboviruses cause disease in hundreds of millions of people worldwide. They can also be transmitted through other modes, such as crossing the placenta, sexually in semen, or during blood transfusions. Zika virus can cause congenital syndrome and perinatal infection in newborns, and can be transmitted sexually in semen, resulting in cases in travelers returning home to temperate climates. Typically, arboviruses pose no greater threat to dentists or their patients than community exposure to bites from insect vectors. INFECTIOUS DISEASE BY ROUTE OF TRANSMISSION IN THE DENTAL SURGERY Direct and indirect contact spread of infection Direct contact is the most common mode of infection spread by dental professionals, involving person-to-person contact or indirectly by touching surfaces contaminated by used equipment or objects like towels. Pathogens transmitted by direct contact include herpes group viruses, varicella zoster virus, and Epstein-Barr virus, as well as viruses causing the common cold or flu. Respiratory viruses are mainly spread through aerosols generated during coughing, but hand placement during coughing or holding a tissue during sneezing can also become contaminated. The Department of Health in England has launched a slogan to reduce the spread of flu in public places. Herpes simplex virus (HSV) is highly infectious, and dental clinics often treat patients with cold sores. Dentists often pick up a second primary HSV through small abrasions on their fingers, known as herpetic whitlows, which can persist for several weeks and prevent work. Viral infections during pregnancy, such as VZV and rubella, pose a risk to unborn fetus and pregnant women. In many countries, including the UK, dentists and clinical members must be vaccinated against these infections to prevent transmission to pregnant women. MRSA, a bacterial infection caused by resistance to methicillin, is the most concerning, especially in oral surgery. About 25-30% of the population are colonized with S. aureus, but only 1-3% of people carry MRSA. The main mode of transmission is through the hands of healthcare workers (HCWs), which may become contaminated by direct contact from colonized or infected patients or objects in the patient's environment. Dentists providing locum services to patients in residential homes should ensure rigorous hand hygiene and use of PPE to reduce their risk of becoming colonized with MRSA. Panton-Valentine Leukocidin (PVL) S. aureus infection primarily affects younger community populations, causing severe skin infections and lung abscesses if left untreated. It primarily affects athletes, children in daycare centers, and intravenous drug users. Poor hygiene and contact precautions increase the risk of occupational infection. Dental teams must practice good hand hygiene and contact precautions. Prevention of person‐to‐person spread of infection The primary source of spread from person to person is by hands and clothing and this route of infection is easily interrupted by hand washing and wearing of gloves and disposable aprons Prevention of indirect spread of infection from equipment Dental instruments must be decontaminated between patients or safely discarded for single-use. Dental impressions should be disinfected to reduce infection risk and comply with postal service regulations. Dental chairs and units must be cleaned and disinfected between patients, facilitated by dividing surgery into zones with varying levels of contamination. Prevention of spread of infection by fluids Dental unit waterlines can spread infection through aerosol and indirect contact. To reduce risks, disinfectants and detergents should be stored in concentrated form, as they can be a source of infection by bacteria like Pseudomonas aeruginosa, which can be resistant to some disinfectants. Food transmission is a concern in society, but should not be a risk in dentistry, as no food should be taken during surgery and adequate kitchen facilities should be provided for staff. Percutaneous transmission of infection Many organizations can be transmitted through percutaneous or mucocutaneous routes, with blood-borne viruses (BBVs) being the primary concern. BBVs with persistent viraemia and replication, such as HIV and hepatitis B and C, pose the most significant cross-infection hazard to healthcare workers. Hepatitis B virus Hepatitis B is a bloodborne and sexually transmitted virus that causes liver inflammation. It is a member of the Hepadnaviridae DNA family and has an incubation period of 45-160 days. In high-prevalence areas, transmission is mostly perinatal or during childhood through horizontal transmission from close household contacts. In low-prevalence countries, transmission usually occurs later in life during heterosexual and homosexual sexual intercourse with an infected partner or by intravenous drug misuse. The natural history of HBV infection is influenced by the age at which an individual is infected. Neonatal infections are usually asymptotically asymptotically, leading to chronic infection (90%), while adult infections are more likely to result in symptomatic acute hepatitis with a lower risk of persistent infection (5-10%). Acutely infected adults often experience fatigue, fever, loss of appetite, nausea, vomiting, abdominal discomfort, joint pain, and jaundice. Chronically infected people develop chronic liver disease, including cirrhosis, liver failure, or liver cancer. The World Health Organization (WHO) reports that a third of the world's population has been infected with Hepatitis B (HBV), with 14 million people chronically infected in the European region. Since 1991, the WHO has recommended universal hepatitis B vaccination for all newborns and children up to 18 years, as well as at-risk groups. This policy has significantly decreased the disease incidence in countries. Vaccination is crucial for HBV prevention in the dental profession and is part of SICP policy. Hepatitis C virus Hepatitis C virus causes both acute and chronic liver infections. Acute HCV infections are usually asymptomatic and rarely life-threatening. About 15-45% of infected individuals clear the virus within six months without treatment. The remaining 55-85% develop chronic HCV infection, often unaware. In chronic HCV patients, 15-20% develop liver cirrhosis within 20 years, with 20% developing liver cancer. The global burden of HCV is estimated at 130-150 million people, with high levels of endemic infection in Africa and Central and East Asia. In the UK, chronic HCV infection has increased by a third over the last decade, with around 214,000 people living with chronic HCV. Most infections occur from needle sharing by people injecting recreational, performance, and image-enhancing drugs or medical and dental unsafe practices. The first proven case of HCV transmission from patient to patient in a dental office occurred in Tulsa, USA, during IV sedation treatment. The dental staff used the same needle to administer the initial dose and any additional top-up drug, but the reused vial was previously used on an HCV seropositive patient. Scientists from the CDC, Atlanta, demonstrated that HCV was transmitted directly due to staff reusing an infected single-use drug vial. HIV transmission HIV transmission is primarily through unprotected sexual intercourse and sharing needles and syringes during drug injections. Effective treatment and prevention measures have reduced routes of transmission, such as mother-to-child transmission and transfusion of HIV-contaminated blood or blood products. Prevention in dental clinics focuses on safe handling and disposal of sharp instruments and staff training. Despite the risk being 100 times less than HBV, stigma and fear of infection have shaken dentists' confidence in infection control measures. However, initiatives have changed the situation, allowing HIV-infected healthcare workers (HCWs) to work as dentists, therapists, and hygienists in most countries, including the UK, and providing post-exposure prophylaxis drugs after exposure incidents. Internationally, routine HIV screening is recommended in healthcare settings and targeted screening for at-risk groups in non-healthcare settings. Undiagnosed individuals cannot benefit from drug treatments that reduce viral load and increase immune function and life expectancy. Early use of combination antiretroviral therapy (cART) before compromised immune systems results in better clinical outcomes for people living with HIV. Daily oral pre-exposure prophylaxis (PrEP) drugs are now recommended for people at substantial risk of HIV infection, such as partners of HIV-infected patients. The UK has achieved the United Nations Ambitious sustainable development goal, aiming for 90% of persons living with HIV to know their serostatus, 90% of those with diagnosed HIV infection receiving ART, and 90% of those receiving ART having viral suppression by 2020. However, there is no room for complacency at the moment, and it is crucial for dental healthcare workers and students to ensure their practice's or dental school's standard infection control measures are sufficient to reduce the risk of HIV and other bloodborne diseases. Spread of infection by air‐borne and respiratory secretions Dental personnel are exposed to aerosolized water from dental unit water lines and patient's saliva, blood, and respiratory secretions generated by high-speed rotary instruments and ultrasonic scalers. The risk of occupational infection is mainly due to legionella and water line management. Aerosols may transmit Mycobacterium tuberculosis and respiratory viruses like rhinoviruses, adenoviruses, influenza, and some herpes viruses like VZV and EBV. Tuberculosis Tuberculosis is a leading cause of death worldwide, alongside HIV/AIDS. Many patients are co-infected with both diseases, requiring active treatment. The World Health Organization (WHO) aims to end the global TB epidemic. Global improvements have been made, with reported TB prevalence 42% lower in 2015 and 86% success rate for new infections. However, many dentists do not perceive TB as a risk due to its prevalence in resource-poor countries. Social factors like urban homelessness, imprisonment history, drug abuse, elderly recurrence, and migration from high-infected areas contribute to the high prevalence of TB. Multidrug-resistant TB accounts for 3.3% of new TB cases and 20% of previously treated cases. Infection transmission from dentist to patient is rare, but a 1982 outbreak of TB affecting tooth sockets in 15 child patients was reported. The UK recommends all new healthcare workers be assessed for personal or family history of TB, as transmission is rare. BCG vaccination should be offered to HCWs, irrespective of age, who: - are previously unvaccinated (that is, without adequate documentation or a characteristic scar), and - will have contact with patients or clinical materials, and - are Mantoux skin test negative (or test positive with an interferon‐gamma release assay for latent TB). To prevent aerosol and splatter transmission, standard precautions include well-ventilated surgery, high-volume suction control, externally ventilated aspiration, wearing masks, goggles, visors, and rubber dams, and controlling aerosols through high-volume suction, externally ventilated aspiration, and wearing respirator masks. Influenza Influenza virus is a respiratory illness causing symptoms like headache, fever, coryza, cough, sore throat, and gastrointestinal issues. It affects around 10% of Europe's population annually, leading to hundreds of thousands of hospitalizations. Influenza-related complications include lower respiratory tract infections, central nervous system involvement, and underlying medical conditions. The incubation period ranges from one to four days, with infectivity being proportional to symptom severity and maximal just after symptom onset. There are two main types, with type A causing more severe symptoms than type B. Because flu usually occurs every winter in the UK, it is referred to as seasonal flu and must be differentiated from pandemic flu and avian flu, which can occur at any time of year. Control of influenza outbreaks worldwide relies on a three‐pronged approach: - annual vaccination of susceptible groups and HCWs - targeted treatment/prophylaxis with influenza antiviral neuraminidase inhibitors (antivirals), for example oseltamivir and zanamivir - hand hygiene and respiratory etiquette Dental professionals with flu-like symptoms should avoid working with patients and colleagues. Health protection authorities monitor seasonal flu strains and vaccine uptake to guide vaccine selection and policies. Health professionals, including dentists, are alerted if flu incidence increases. Influenza viruses are spread through respiratory secretions, which can be transmitted through direct contact on hands and contact with large droplets contaminating surfaces. They can survive on surfaces like glass or plastic for up to 24 hours, and on porous materials for 2-4 hours. Deactivation of influenza viruses is easy through hand washing with soap and water or alcohol-based hand sanitizers, and cleaning surfaces with household detergents. HCWs are strongly encouraged to be vaccinated annually against seasonal flu. Pandemic influenza and avian flu Pandemics occur when a new virus emerges that can cross national boundaries and infect large numbers of people worldwide. The 1918-19 influenza pandemic, a new subtype of influenza, killed 40-50 million people. Most people are non-immune to the new virus, except for the elderly. There have been three subsequent pandemics, 1957-8, 1968-9, and 2009-10. There are ongoing concerns that circulating avian influenza virus strains or novel reassortments of human with animal or bird flu virus strains may lead to the next pandemic influenza virus. In the event of an outbreak, precautions are similar to seasonal flu, with a national contingency plan and instructions for healthcare workers (HCWs) to present for vaccination and acquire prophylactic anti-viral drugs. Strict adherence to standard infection control practices, such as PPE and hand washing, is essential. EMERGING AND RE‐EMERGING PATHOGENS Emerging and re‐emerging infections are diseases that are reported in a population for the first time, or that may have existed previously but are rapidly increasing in incidence or geographic range. Infections can emerge via a variety of different processes. - Novel pathogens arising de novo due to genetic mutations or evolution of existing human or animal infections, for example pandemic influenza, vCJD, MERS. - Known infections spreading to new geographic areas or populations, such as West Nile virus in the USA, Ebola in West Africa, Zika virus into Central and South America. - Previously unreported infections appearing in areas undergoing climate change, such as chikungunya and dengue. - Old infections re‐emerging as a result of changes in host immunity, antimicrobial selection and resistance or breakdowns in public health measures such as national vaccination campaigns, for example polio, syphilis, diphthe- ria and MDR‐TB. Infections increase in prevalence when conditions allow transmission and may recede over time, as seen in West African Ebola virus disease in 2013-15 and pandemic influenza outbreaks in 2010. Why do infections emerge? Globalization, climate change, agricultural practices, urbanization, antibiotic selection, and population health status can all contribute to the spread of diseases. Mosquitoes and other insect vectors are major modes of transmission for blood-borne viral infections like dengue, chikungunya, Zika, and West Nile virus. Climate change has allowed disease-carrying mosquitoes to survive in northern European countries, while malaria-carrying mosquitoes are predicted to thrive in southern England by 2030-50. Increased travel and migration have also contributed to the spread of infection, with the Black Death in the Middle Ages linked to increased travel by ships and new risks posed by increased air travel. In 2013, 842 million people traveled by air in the European Union, with 39% of these flights being to countries outside the EU. Information on recent travel outside the country of origin is crucial for identifying emerging infections. The impact of emerging infections on dentistry Emerging pathogens in dentistry pose challenges to infection control and prevention protocols, prompting questions about transmission risks in dental surgery. Novel infections can shake public and dental team confidence, necessitating education on these diseases for risk assessments and reassuring the public that dental treatment is safe. Therefore, it is crucial to educate ourselves and the public about these emerging pathogens. Zoonosis and the evolution of novel infections Microbes like avian influenza, rabies, Ebola, Middle Eastern respiratory virus (MERS), and Salmonella use wild or domestic animals as their primary hosts and occasionally infect humans. These zoonotic infections, which can be transmitted through direct contact with the living animal, their meat, secretions, or vector transmission via insect bites, are crucial in the evolution of novel infections affecting human populations. Emerging zoonotic infections pose a significant risk to human populations, as there may be no or limited natural immunity to these novel infections. Zoonoses can occur in farm animals like cattle, but when the reservoir is in a wild forest animal like the fruit bat, mass culling is not an option. The Ebola outbreak in West Africa (2013-15) was brought under control through a concerted national and international campaign that relied on well-tried measures from the pre-antimicrobial era, including public education, contact tracing, quarantine, local curfews, border controls, modification of burial practices, and rigorous infection control and prevention measures. Operative dentistry could potentially offer a secondary route for person-to-person transmission of zoonotic infections, with two examples affecting the dental profession. Novel coronavirus infections SARS-CoV and MERS-CoV are coronaviruses that cause severe acute respiratory illnesses. SARS emerged in China in 2003, resulting in 8437 probable cases and 813 deaths. It was successfully eradicated, and lessons were learned from its management. A decade later, MERS-CoV emerged in the Middle East. SARS was a superspreader, spreading rapidly from China to Canada. The virus had multiple replication sites and was spread through respiratory secretions and feces. Infectivity increased as the disease progressed, reaching a maximum around day 10 when patients were very seriously ill. MERS transmission follows a similar pattern, with initial epidemiological findings indicating sporadic zoonotic infections from human contact with camel secretions and meat. However, onward transmission is now mainly from person to person. MERS outbreaks are often linked to delays in case identification, multiple healthcare contacts, and gaps in infection control protocols. In 2015, a large outbreak in South Korea resulted from an imported Middle Eastern doctor, leading to 186 cases and 36 deaths. All cases were linked to a single transmission chain at the hospital where the doctor was treated. This incident serves as a lesson for dentistry professionals, as Hong Kong's dental school closed for months during the 2003 SARS outbreak to protect the public, staff, and students from additional exposure to SARS due to increased risk of respiratory transmission from dental aerosols. Variant Creutzfeldt–Jakob disease and transmissible spongiform encephalopathy agents The prion disease (vCJD) was first diagnosed in 1995 and has since peaked in 2000, with approximately 229 deaths worldwide. The disease is caused by a 'rogue protein' molecule called a prion, which belongs to a group of diseases known as transmissible spongiform encephalopathies (TSE). Unlike CJD prions, vCJD prions are detected in the central nervous system, peripheral nervous system, and lymphoid tissues. In 2003-2004, four cases of vCJD transmission were reported in the UK, three via blood transfusion and one from plasma-derived products. However, blood does not appear to be an efficient vehicle for transmission of vCJD. Prions have also been identified in the trigeminal ganglion and tonsils from vCJD patients at postmortem. Dental pulp, composed of vascularal and peripheral nerve tissue, has been shown to be infected with vCJD in animal studies. Despite its low fatality rate and slow global spread, vCJD has had a significant impact on dentistry practices and raised awareness of prion disease internationally. The study reveals that around one in 2000 people in the UK may be a carrier of vCJD, with over 6350 patients potentially exposed to vCJD or CJD through surgical instruments, dura mater grafts, human-derived growth hormones, or blood/pooled plasma transfusions. These patients pose a small but significant public health risk due to potential transmission of vCJD or CJD. They are notified of the risk and are monitored long term. The extrapolated figures suggest that approximately one in 2000 people in the UK may be a carrier of vCJD. To identify such patients, dentists are advised to include the following question on medical history and consent forms: Have you ever been notified that you are at increased risk of CJD or vCJD for public health purposes? The future number of patients with CJD or vCJD is unknown, but our knowledge base continues to evolve. As a precaution, at-risk patients are advised not to donate blood, tissues, or organs and should inform their medical and dental carers before any invasive procedures. If invasive treatment is required, the patient should be managed in secondary care as the instruments used may require quarantine or disposal. Patients with or at increased risk of CJD or vCJD should not be refused routine dental treatment. Instruments used on them can be safely decontaminated using the methods described in Chapter 7. NHS England stated that the risk of transmission from dental instruments is very low provided optimal standards of infection control and decontamination are maintained. However, the definition of optimal decontamination standards can vary greatly between countries. The CJD International Surveillance Unit is collecting data to identify secondary routes of transmission of vCJD, including dentistry. Much of the guidance outlined in this book aims to improve decontamination processes to ensure instruments used on patients who may be unknown carriers can be safely reused on other patients. Routine sterilization at 134°C does not guarantee complete inactivation of prions, so the emphasis has shifted to highly effective pre sterilization washing and rinsing of instruments to remove and destroy prion protein prior to sterilization. In summary, accurate information regarding the routes of transmission of new or emerging infections allows dental teams to remain resilient to challenges. By using the dual concepts of chain of infection and standard precautions, infection control protocols in dentistry can be modified to cope with new situations.

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