A dental aerosol is an aerosol that is produced from dental instrument, dental handpieces, three-way syringes, and other high-speed instruments. These aerosols may remain suspended in the clinical environment. [1] Dental aerosols can pose risks to the clinician, staff, and other patients. The heavier particles (e.g., >50 µm) contained within the aerosols are likely to remain suspended in the air for relatively short period and settle quickly onto surfaces, however, the lighter particles may remain suspended for longer periods and may travel some distance from the source. [2] These smaller particles are capable of becoming deposited in the lungs when inhaled and provide a route of diseases transmission. [3] Different dental instruments produce varying quantities of aerosol, and therefore are likely to pose differing risks of dispersing microbes from the mouth. Air turbine dental handpieces generally produce more aerosol, with electric micromotor handpieces producing less, although this depends on the configuration of water coolant used by the handpiece. [4] [5]
These dental aerosols are bioaerosols which may be contaminated with bacteria, fungi, and viruses from the oral cavity, skin, and the water used in dental units. [6] Dental aerosols also have micro-particles from dental burs, and silica particles which are one of the components of dental filling materials like dental composite. [7] Depending upon the procedure and site, the aerosol composition may change from patient to patient. Apart from microorganisms, these aerosols may consist of particles from saliva, gingival crevicular fluid, blood, dental plaque, calculus, tooth debris, oronasal secretions, oil from dental handpieces, and micro-particles from grinding of the teeth and dental materials. [8] They may also consist of abrasive particles that are expelled during air abrasion and polishing methods. [3]
Dental aerosols contain a wide range of particles with the majority being less than 50 µm. The smaller particles with size between 0.5 and 10 µm are more likely to be inhaled and have the potential to transmit infection. [3] Smaller particles are likely to remain suspended for longer periods of time, and may travel further from the source. Settling time of particles is described by Stokes' law in part as a function of their aerodynamic diameter.
The water used in the dental units may be contaminated with Legionella , and the aerosols produced by dental handpieces may contribute to the spread of the Legionella in the environment; there is therefore a risk of inhalation by the dentist, staff and patients. [9] The dental unit water lines (DUWLs) may also be contaminated with other bacteria like Mycobacterium spp and Pseudomonas aeruginosa . [10] Infection from Legionella species causes infections like Legionellosis and several pneumonia like diseases. [11] However, still there is no strong evidence that suggests the dentists are at greater occupational risk from Legionella. [9] Transmission of tuberculosis also occurs from the cough producing procedures on the patients with tuberculosis that involve production of aerosols. [12] Mycobacterium tuberculosis is transmitted in the form of droplet nuclei which are smaller than 5 µm which stay suspended in the environment for longer duration. The development of active tuberculosis in Dental Health Care Workers (DHCWs) is less likely than the rest of the other Health Care Workers (HCWs). There are lacking evidences to prove the active tuberculosis development resulting from this transmission in Dental health care Workers (DHCWs). [13]
The virus that caused the COVID-19 pandemic is named as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by the International Committee on Taxonomy of Viruses (ICTV) on 11 February 2020. [14] SARS-CoV-2 remains stable in aerosols for several hours. [15] The virus is viable for hours in aerosols and for few days on surfaces, hence the transmission of SARS-CoV-2 is feasible through aerosols and also shows fomite transmission. [16]
Dentists have previously been described as one of the top of the working groups with high risk of exposure to SARS-CoV-2. Due to the close proximity of the dental health care workers to the patients, dental procedures involving aerosol production is not advisable in patients who tested positive for COVID-19 except for emergency dental treatment. [17] On 16 March 2020, the American Dental Association (ADA) has advised dentists to postpone all elective procedures. [18] ADA also developed guidance specific to address dental services during the COVID-19 pandemic. [19]
Elements like calcium, aluminium, silica and phosphorus can also be found in the dental aerosols produced during the procedures like debonding of orthodontic appliances. [20] These particles may range from 2 to 30 µm in diameter and there are chances of inhaling them. [21]
A number of methods have been proposed, and are widely used, to control dental aerosols and reduce risk of disease transmission. For example, dental aerosols can be controlled or reduced using dental suction, [22] rubber dam, [5] alternative handpieces, [2] and local exhaust ventilation (extra-oral suction). [23]
Dentistry, also known as dental medicine and oral medicine, is the branch of medicine focused on the teeth, gums, and mouth. It consists of the study, diagnosis, prevention, management, and treatment of diseases, disorders, and conditions of the mouth, most commonly focused on dentition as well as the oral mucosa. Dentistry may also encompass other aspects of the craniofacial complex including the temporomandibular joint. The practitioner is called a dentist.
A dentist, also known as a dental surgeon, is a health care professional who specializes in dentistry, the branch of medicine focused on the teeth, gums, and mouth. The dentist's supporting team aids in providing oral health services. The dental team includes dental assistants, dental hygienists, dental technicians, and sometimes dental therapists.
Teeth cleaning is part of oral hygiene and involves the removal of dental plaque from teeth with the intention of preventing cavities, gingivitis, and periodontal disease. People routinely clean their own teeth by brushing and interdental cleaning, and dental hygienists can remove hardened deposits (tartar) not removed by routine cleaning. Those with dentures and natural teeth may supplement their cleaning with a denture cleaner.
A surgical mask, also known by other names such as a medical face mask or procedure mask, is a personal protective equipment used by healthcare professionals that serves as a mechanical barrier that interferes with direct airflow in and out of respiratory orifices. This helps reduce airborne transmission of pathogens and other aerosolized contaminants between the wearer and nearby people via respiratory droplets ejected when sneezing, coughing, forceful expiration or unintentionally spitting when talking, etc. Surgical masks may be labeled as surgical, isolation, dental or medical procedure masks.
Tooth whitening or tooth bleaching is the process of lightening the color of human teeth. Whitening is often desirable when teeth become yellowed over time for a number of reasons, and can be achieved by changing the intrinsic or extrinsic color of the tooth enamel. The chemical degradation of the chromogens within or on the tooth is termed as bleaching.
Legionella longbeachae is one species of the family Legionellaceae. It was first isolated from a patient in Long Beach, California. It is found predominantly in potting soil and compost. Human infection from L. longbeachae is particularly common in Australia, but cases have been documented in other countries including the United States, Japan, Greece and the UK.
A dental drill or dental handpiece is a hand-held, mechanical instrument used to perform a variety of common dental procedures, including removing decay, polishing fillings, performing cosmetic dentistry, and altering prostheses. The handpiece itself consists of internal mechanical components which initiate a rotational force and provide power to the cutting instrument, usually a dental burr. The type of apparatus used clinically will vary depending on the required function dictated by the dental procedure. It is common for a light source and cooling water-spray system to also be incorporated into certain handpieces; this improves visibility, accuracy and overall success of the procedure. The burrs are usually made of tungsten carbide or diamond.
Dental assistants are members of the dental team. They support a dental operator in providing more efficient dental treatment. Dental assistants are distinguished from other groups of dental auxiliaries by differing training, roles and patient scopes.
A health professional, healthcare professional, or healthcare worker is a provider of health care treatment and advice based on formal training and experience. The field includes those who work as a nurse, physician, physician assistant, registered dietitian, veterinarian, veterinary technician, optometrist, pharmacist, pharmacy technician, medical assistant, physical therapist, occupational therapist, dentist, midwife, psychologist, audiologist, or healthcare scientist, or who perform services in allied health professions. Experts in public health and community health are also health professionals.
Airborne transmission or aerosol transmission is transmission of an infectious disease through small particles suspended in the air. Infectious diseases capable of airborne transmission include many of considerable importance both in human and veterinary medicine. The relevant infectious agent may be viruses, bacteria, or fungi, and they may be spread through breathing, talking, coughing, sneezing, raising of dust, spraying of liquids, flushing toilets, or any activities which generate aerosol particles or droplets. This is the transmission of diseases via transmission of an infectious agent, and does not include diseases caused by air pollution.
The Wells curve is a diagram, developed by W. F. Wells in 1934, which describes what is expected to happen to small droplets once they have been exhaled into air. Coughing, sneezing, and other violent exhalations produce high numbers of respiratory droplets derived from saliva and/or respiratory mucus, with sizes ranging from about 1 µm to 2 mm. Wells' insight was that such droplets would have two distinct fates, depending on their sizes. The interplay of gravity and evaporation means that droplets larger than a humidity-determined threshold size would fall to the ground due to gravity, while droplets smaller than this size would quickly evaporate, leaving a dry residue that drifts in the air. Since droplets from an infected person may contain infectious bacteria or viruses, these processes influence transmission of respiratory diseases.
A respiratory droplet is a small aqueous droplet produced by exhalation, consisting of saliva or mucus and other matter derived from respiratory tract surfaces. Respiratory droplets are produced naturally as a result of breathing, speaking, sneezing, coughing, or vomiting, so they are always present in our breath, but speaking and coughing increase their number.
A toilet plume is the dispersal of microscopic particles as a result of flushing a toilet. Normal use of a toilet by healthy individuals is considered unlikely to be a major health risk. However this dynamic changes if an individual is fighting an illness and currently shedding out a virulent pathogen in their urine, feces or vomitus. There is indirect evidence that specific pathogens such as norovirus or SARS coronavirus could potentially be spread by toilet aerosols, but as of 2015, no direct experimental studies had clearly demonstrated or refuted actual disease transmission from toilet aerosols. It has been hypothesized that dispersal of pathogens may be reduced by closing the toilet lid before flushing, and by using toilets with lower flush energy.
Occupational hazards in dentistry are occupational hazards that are specifically associated with a dental care environment. Members of the dental team, including dentists, hygienists, dental nurses and radiographers, must ensure local protocols are followed to minimize risk.
Hazard controls for COVID-19 in workplaces are the application of occupational safety and health methodologies for hazard controls to the prevention of COVID-19. Vaccination is the most effective way to protect against severe illness or death from COVID-19. Multiple layers of controls are recommended, including measures such as remote work and flextime, increased ventilation, personal protective equipment (PPE) and face coverings, social distancing, and enhanced cleaning programs.
An aerosol-generating procedure (AGP) is a medical or health-care procedure that a public health agency such as the World Health Organization or the United States Centers for Disease Control and Prevention (CDC) has designated as creating an increased risk of transmission of an aerosol borne contagious disease, such as COVID-19. The implication is that the risk of transmission of the contagious disease from a patient having an AGP performed on them is higher than for a patient who is not having an AGP performed upon them. This then informs decisions on infection control, such as what personal protective equipment (PPE) is required by a healthcare worker performing the medical procedure.
Catherine Jane Noakes is a British mechanical engineer who is Professor of Environmental Engineering for Buildings at the University of Leeds. Noakes specialises in airborne infections and the transport of airborne pathogens. During the COVID-19 pandemic, Noakes served on the Government of the United Kingdom Scientific Advisory Group for Emergencies (SAGE).
Source control is a strategy for reducing disease transmission by blocking respiratory secretions produced through speaking, coughing, sneezing or singing. Surgical masks are commonly used for this purpose, with cloth face masks recommended for use by the public only in epidemic situations when there are shortages of surgical masks. In addition, respiratory etiquette such as covering the mouth and nose with a tissue when coughing can be considered source control. In diseases transmitted by droplets or aerosols, understanding air flow, particle and aerosol transport may lead to rational infrastructural source control measures that minimize exposure of susceptible persons.
The transmission of COVID-19 is the passing of coronavirus disease 2019 from person to person. COVID-19 is mainly transmitted when people breathe in air contaminated by droplets/aerosols and small airborne particles containing the virus. Infected people exhale those particles as they breathe, talk, cough, sneeze, or sing. Transmission is more likely the closer people are. However, infection can occur over longer distances, particularly indoors.
Lidia Morawska is a Polish–Australian physicist and distinguished professor at the School of Earth and Atmospheric Sciences, at the Queensland University of Technology and director of the International Laboratory for Air Quality and Health (ILAQH) at QUT. She is also co-director of the Australia-China Centre for Air Quality Science and Management, an adjunct professor at the Jinan University in China, and a Vice-Chancellor fellow at the Global Centre for Clean Air Research (GCARE), University of Surrey in the United Kingdom. Her work focuses on fundamental and applied research in the interdisciplinary field of air quality and its impact on human health, with a specific focus on atmospheric fine, ultrafine and nanoparticles. Since 2003, she expanded her interests to include also particles from human respiration activities and airborne infection transmission.