key: cord-0828282-h98jmfax authors: Amante, Luís Filipe Lima Sobral; Afonso, João Torres Monteiro; Skrupskelyte, Greta title: Dentistry and the COVID-19 outbreak date: 2020-12-19 journal: Int Dent J DOI: 10.1016/j.identj.2020.12.010 sha: d328e667baa36a2e147a7bf2448bb5851a6f60f3 doc_id: 828282 cord_uid: h98jmfax Introduction Infection prevention in dental practice is a principle of utmost importance aiming to protect patients, the dental team and ultimately public health. A recent pandemic of coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has instigated widespread public concerns worldwide. This highly contagious disease has called for profound changes in patient care around the world. The goal of this article is to review the current literature and introduce essential knowledge about COVID-19, recommend management protocols and adequate protection for dental professionals during the outbreak. Material and methods The literature search was conducted from April to June 2020. After full-text screening a total of 85 studies were included. Results Given the novelty of SARS-CoV-2, some characteristics of the virus remain yet unknown. The virus is aerosol-transmissible and, due to the nature of dental procedures, this puts dental professionals and patients at a high risk of contamination by this pathogen. Adequate management protocols and specific protective approaches are essential to minimize the spread of COVID-19 in dental settings during the outbreak. Discussion The overall impact of COVID-19 in healthcare worldwide is yet to be determined. This constitutes a significant limitation to this review, as the information obtained, risks being outdated as the pandemic progresses. The prudent practitioner will use this review as a starting point and continue to pro-actively update themselves as the outbreak continues. Further studies are required to investigate the potential impact of infections with SARS-CoV-2 within the dental settings. Dentistry is a field of medicine that involves a very close proximity of the dental professionals and the patient's oral cavitya biological niche that can harbour opportunistic and pathogenic microorganisms that can pose a risk for cross contamination, infection and may eventually result in systemic infections (1) . Moreover, the risk of exposure in procedures conducted by dentists is amplified due to the open and invasive nature of dental procedures. Despite this, until recently, the transmission of infectious pathogens among patients and dental professionals has been reported as rare in the literature and was often caused by breakdowns in simple infection prevention procedures including failures in the sterilization cycle of dental hand-pieces or instruments between patients, failure to adequately monitor autoclaves (i.e. conduct spore testing), as well as unsafe injection practices (2). The main purpose of infection control in dental practice should be the prevention of possible transmission of disease-causing agents like bacteria, viruses, fungi etc. between patients and from patients to the dental team and vice versa (3). Traditionally, based on the routes of transmission, diseases can be classified as blood-borne, air-borne or spread through fomites (objects that may be contaminated with infectious organisms and serve in their transmission). As healthcare providers, dentists have the responsibility of understanding these diseases and look to implement strict protocols and protective measures during the provision of dental care to reduce their potential spread within the clinical arena (3). Patient's bodily fluids such as blood and saliva can become major vectors of crosstransmission in dental practice. The contact of infectious materials through lesions on skin and mucosa can potentially cause blood-borne contamination. The emanation of pathogens caused through the spray of dental hand-pieces can also be considered an air-borne means of transmission, potentially affecting both patients and dental professionals. Generally, the risk of any such transmissions depends on a number of factors: the dose of the pathogens transmitted, the virulence of the pathogen, the frequency or probability of exposure to the infectious material and finally the state of the host immune system (1) . Nosocomial infections are infections occurring in a patient in a healthcare setting, in whom the infection was not present or incubating at the time of admission. This may include infections acquired in the hospital or dental practice but appearing after discharge as well as occupational infections transmitted among staff of the facility. Several viruses can be transmitted through nosocomial infections including: the hepatitis B and C viruses, enteroviruses, respiratory syncytial virus (RSV), rotavirus, cytomegalovirus, Ebola virus, human immunodeficiency virus (HIV), herpes simplex virus, influenza viruses and varicella-zoster virus (4). Healthcare professionals have a serious responsibility of preventing nosocomial infections and therefore should abide to strict rules and protocols for this purpose. On December 2019, an outbreak of viral pneumonia caused by a previously unknown coronavirus originated in Wuhan, China. This disease was caused by a novel severe acute respiratory syndrome coronavirus 2 -SARS-CoV-2and has since spread throughout the planet becoming a major challenge for public health (5,6). The progression of the outbreak led to the World Health Organization (WHO) to declare it a public health emergency of international concern on January 30 and on February 11 to officially name it corona virus disease 2019 (COVID-19) (7). Due to the characteristics of dental treatments, there is a considerable risk of cross infection with this novel virus in dental settings. (8) . Researchers have identified SARS-CoV2 in saliva of infected patients and the transmission routes of the disease suggest that dental professionals and patients are potentially at a considerable risk of infection with this highly contagious pathogen (9), (Fig.1) . Therefore, dental professionals have the responsibility to be well informed about the disease, be strict with their infection control protocols and policies, as well, as being diligent in protecting the population against the rampant dissemination of this public health threat (10). The goal of this article is to review the current literature and introduce essential knowledge about COVID-19 and provide recommended management protocols, including adequate protection for dental professionals during this viral outbreak. Materials and methods: PubMed, Elsevier, ScienceDirect and World Health Organisation WHO databases were used to search for the material published until 30.6.2020 using the following: "infections in dentistry" COVID-19 is the name given to the infectious disease caused by the most recently discovered coronavirus -previously dubbed 2019-nCoV, and now officially called SARS-CoV-2 (5). This new strain of the virus and its associated disease were completely unknown before the outbreak began in Wuhan, China, in December 2019 (5). Coronaviruses are part of a large family of single-stranded RNA pathogens known as Coronaviridae of the order Nidovirales (11). The virus is comprised of a large, positive-sense single-stranded RNA encapsulated in a lipid bilayer envelope (12,13). The infection with coronavirus usually produces mild respiratory symptoms in humans. Having said that, in 2002, the severe acute respiratory syndrome coronavirus (SARS-CoV) and in 2012, the Middle East respiratory syndrome coronavirus (MERS-CoV), were responsible for worldwide outbreaks and severe fatal respiratory diseases (14, 15, 16, 17, 18) . This family of viruses is zoonotic meaning it can be transmitted from animals to humans. The interspecies transmission can be far more dangerous as the new host immune system is not adapted to tackle the pathogen and this constitutes a key aspect to explain the recent pandemic. Given the novelty of COVID-19, some of the characteristics of the virus remain yet unknown. The common symptoms of COVID-19 at illness onset are fever, fatigue, dry cough, myalgia, and dyspnea. These symptoms are frequently mild and start gradually. Some patients can experience headache, dizziness, abdominal pain, diarrhea, nausea and vomiting (19) . According to the latest available published data by the WHO approximately 1 out of every 6 people infected with SARS-CoV-2 becomes seriously ill and develops breathing difficulties (4). Furthermore, one-fourth to one-third of hospitalized patients in Wuhan were reported to have developed severe complications, such as acute respiratory distress syndrome, arrhythmia and shock, and had to be admitted to intensive care units (20, 21, 22) . The literature states that approximately 80% of COVID-19 patients only experienced minor symptoms, often similar to the ones expected with flu or seasonal allergies. (23) This feature of the disease has caused an increased number of undiagnosed cases and has played a quintessential role on the progression of the pandemic (23) . The onset of COVID-19 disease may result in progressive respiratory failure, caused by alveolar damage and eventually death (24) . Presently, there is still a lack of robust estimates for case fatality rates and the numbers available are potentially biased by incomplete outcome data and inconsistencies in testing policies. The mean crude case-fatality (proportion of deaths among total cases reported) from the EU/EEA and the UK by 23 March 2020 was reported to be 5.4% (25). According to Malik et al. the reported fatality rate (cumulative deaths divided by cumulative cases) of COVID-19 in China varied between 0.39% and 4.05% depending on the different regions of the country. These numbers are reported to be lower when compared to SARS (≈10%) and MERS (≈34%) and higher than seasonal influenza (0.01% to 0.17%) according to the data published by the US centres for disease control and prevention (26) . The literature suggests that factors such as older age and the existence of predisposing comorbidities (i.e. cardiovascular disease, diabetes and hypertension) were associated with worse prognosis (21, 27, 28) . Nevertheless, current observations have established that people of all ages and without prior comorbidities can be susceptible to COVID-19. The current numbers published daily by the WHO report an excess of 10 million people infected with SARS-CoV-2 worldwide and hundreds of thousands of deaths recorded and the progression of the numbers of the pandemic outbreak is still a worrying uncertainty (4, 29). The Chinese Center for Disease Control and Prevention were first to isolate the virus on the 9 th of January 2020 and published the viral genome sequence data in international database banks GenBank and the Global Initiative on Sharing All Influenza Data (GISAID) (20, 29) . As soon as this important data became available it enabled laboratories and researchers worldwide to start working to develop unique tests focusing on the diagnosis of COVID-19 (21, 30) . There is a current consensus that the diagnosis of infection with SARS-CoV-2 should be based on a combination of epidemiologic information, clinical symptoms, CT/chest X-Rays imaging findings (most positive patients showed bilateral pneumonia, with ground-glass opacity and bilateral patchy shadows) and laboratory tests (i.e. reverse transcription polymerase chain reaction [RT-PCR] on respiratory tract specimens) (20, 29, 31, 32) . At the time of writing this article, swabs of upper respiratory tract samples (usually obtained from throat and nose) were being widely used for the purpose of diagnosing COVID-19. The literature also suggests that salivary diagnosis platforms can be helpful in diagnosing the disease (33, 34) . The virus can be detected in saliva for several days after infection (10). Moreover, the collection of saliva is a comfortable, easy, inexpensive and non-invasive approach, that requires minimal equipment and can also minimize the risk of nosocomial transmission of COVID-19 to healthcare workers (35) . At the time of writing this article, there were no vaccines or specific anti-viral medications that had been approved or scientifically proven to prevent or treat the infection with SARS-Cov-2 in humans (29). Currently, the approach to patients with COVID-19 is to control the source of infection, use infection prevention and control measures to reduce the risk of transmission (21) . Providing early diagnosis, isolation and supportive care have been proven essential to control the progression of the pandemic and should be considered priorities for affected patients (21) . Most patients recover due to supportive care but people with serious illness should be hospitalized (29). Multiple research teams worldwide are currently working to produce a solution for this global pandemic (36). A team of international researchers from the Universities of Melbourne, Athens, Radboud and Exeter are presently organizing randomized control studies to investigate the effects of a genetically modified vaccine for tuberculosis called VPM1002 on COVID-19. This has stemmed from a research by Netea et al. published in 2016, where the authors discussed the concept of -trained immunity‖ and tested the hypothesis of the vaccine revving up the human immune system in a broad way, allowing it to better fight SARS-CoV-2 and, perhaps, prevent infection altogether (37) . Kim et al. in April 2020, suggested a microneedle array (MNA) delivery system of recombinant coronavirus vaccines as a possible immunisation solution for COVID-19. By targeting the spike (S) proteina component of a viral envelope in coronavirusesthe research team has produced a clinically-translatable vaccine for human testing (38) . The MNA delivery system is designed to be applied on the skin without the need for an applicator or any specialized equipment, supporting the potential for self-administration which can become a tremendous advantage in a pandemic scenario (38) . The WHO is coordinating efforts to develop vaccines and medicines to prevent and treat COVID-19 in a race against the progression of the pandemic (4). Safe vaccines that rapidly induce potent and long-lasting virus-specific immune responses against COVID-19 are urgently needed. At the time of writing of this article there were several confirmed active projects in exploratory or pre-clinical stages, and the first COVID-19 vaccine candidate had entered human clinical testing with unprecedented rapidity (39). Currently, the transmission routes of COVID-19 are still to be completely determined (30, 40) . The incubation period for individuals infected with this virus can be asymptomatic and has been reported to be ~2-14 days. It has been shown that people are most infectious in the first week after becoming infected with SARS-CoV-2, in which they show no or few symptoms (20, 31, 41, 42) . This epidemiologic feature of COVID-19 has made its control particularly challenging (43) . It is also unclear if the virus can be transmitted from mothers to their babies while they are still pregnant (vertical transmission), during labour and birth, or following birth (44, 45, 46) . Furthermore, it remains yet unknown whether patients in the recovering phase can also be potential sources of infection (43) . The virus is mainly transmitted by direct transmission (cough, sneeze, and droplet inhalation), contact transmission (contact with oral, nasal and eye mucous membranes) and fomites (inanimate objects that, when contaminated with or exposed to infectious pathogens, can transfer disease to a new host) (9,47). Contact with aerosols generated during clinical procedures has also been established as a transmission route for COVID-19 (47). Aerosol is defined as a particle which is smaller than 50µm in diameter-small enough to stay in the air before settling down or entering the respiratory tract (48). Diseases such as the Pneumonic plague, Influenza, Legionnaire's disease, and SARS are also transmitted through aerosol (49, 50, 51, 52) . Contaminated blood samples -often used to perform laboratory diagnostic testscan also be considered possible transmission routes for SARS-CoV-2 (47). Patients with COVID-19, even if asymptomatic, can render the virus airborne by spreading droplets when speaking, coughing or sneezing, potentially infecting individuals in close contact (≈ 6 ft / 1.80 m) which poses a major everyday personal contact risk (53, 54). This characteristic is believed to be the main route for contamination for COVID-19 and it has originated the generalised recommendation of social distancing (53). The source of droplets can be nasopharyngeal or oropharyngeal, generally associated with saliva. Smaller droplets are responsible for the long-distance contamination, as airborne pathogens can remain suspended in the air for longer periods (55, 56) . Larger droplets are too heavy to remain in suspension in the air and tend to fall on floors or other surfaces, potentially contaminating instruments and/or environmental surfaces (57) . The literature reports that human coronaviruses are able to persevere on surfaces such as metal, glass, or plastic for several days (55, 58) . This characteristic also enables a possible viral transmission between patients and healthcare providers by contact with fomites. Stethoscopes and neckties are common fomites associated with nosocomial infections (59) . In addition, at room temperature the viral particles of SARS-CoV-2 without the host remain infectious from 2h up to 9 days, and persist better at higher (50%) compared to lower (30%) humidity (59) . There is a variation of advice across the world about how dentists should treat patients during the COVID-19 pandemic. This can make it difficult to decide what is the best way to manage dental patients, especially those who are in pain (60). Since January 2020 in most cities of China, routine dental procedures have been deferred until further notification and only emergency treatments have been performed using strict infection prevention and control measures (8) . On 16 March 2020, the American Dental Association (ADA) issued an advice recommending that dentists should suspend elective procedures for the following three weeks and focus on providing treatment for dental emergencies only (54) . The British General Dental Council (GDC), in a statement issued in March 2020, also emphasised that -in many cases, the right approach will be to stop providing treatment altogether‖ in dental primary care during the COVID-19 outbreak (60). More recently, as the pandemic continues to evolve, dental authorities around the world have recognized that dentists may gradually need to start delivering non-emergency dental care, whilst strictly complying with protocols that should aim to minimize the risks to patients and to the dental professionals (61,62). Due to the unique characteristics of dental procedures the standard protective measures in daily clinical work are likely to be ineffective in preventing the progression of this highly contagious virus. This is particularly relevant as patients may attend for their treatments whilst in the incubation period of the disease and possibly unaware or even unwilling to disclose their infection. It is essential that dental professionals should be familiarized with the transmission routes of SARS-CoV-2, how to potentially identify patients with the infection and to strictly abide to effective protective measures and infection control protocols during clinical practice. After a careful literature analysis, the authors suggest the following infection control measures and protocols to be followed by dental professionals during this pandemic outbreak (Table 2) : Evaluation and Triaging of Patients (Fig.2) During the outbreak of COVID-19, dental surgeries should not be operating on an -open-door‖ basis and patients should be encouraged not to attend the dental healthcare facility without a previous triage process. The British Dental Association (BDA) envisage that in the vast majority of cases, telephone triaging of patients during the COVID-19 outbreak will be appropriate (60). The triage should ideally be done by a dentist that has full access of patient's records. This allows the dentist to be in full possession of the issues that will impact on the clinical risk assessment needed such as: medical history; existing comorbidities; ongoing, recently completed or planned treatment; history of current problem and social history. After a consultation and a careful risk assessment, it is perfectly acceptable to provide telephone advice and eventually issue prescriptionswhen possibly remotelyof antibiotics or other medications where relevant (60). The British Faculty of General Dental Practitioners (FGDP) stresses that, during the COVID-19 outbreak, antimicrobials should be prescribed in a responsible manner and only where clinically indicated, and dentists should consult their Antimicrobial Prescribing for General Dental Practitioners for guidance (63) . This document states that -the prescribing of antibiotics for toothache, including acute pulpitis, is inappropriate as they are of no clinical benefit in managing dental pain. Analgesics can provide pain relief prior to provision of definitive treatment‖. Furthermore, this guidance notes that -antimicrobials may be appropriate where patients present with an acute dental infection for which definitive treatment has to be delayed because of a need to refer for specialist services due to an inability to establish drainage. It may therefore be appropriate to prescribe antimicrobials based on a provisional diagnosis, conducted remotely, of a swelling associated with an acute dental infection‖ (63) . This approach may offer symptomatic relief to patients and provide dental professionals with some time to develop a strategy to deliver the required dental care with all the appropriate measures in place to prevent the spread of infection (54) . Any patient prescribed antimicrobials should be rapidly referred for definitive treatment in an urgent care setting to avoid repeat prescribing of antimicrobials‖ (63) . The most updated COVID-19 guidance issued by the BDA has suggested a list of non-clinical risk assessment factors for considering whether to treat a patient face-to face. A non-exhaustive list of these factors, in no order of priority, is displayed on table 1. If the triage / assessment process concludes that the patient needs to be seen, it is essential to ascertain the potential risk of SARS-CoV-2 infection and how to better deal with the patient´s treatment needs accordingly. Patients that have suspected or confirmed COVID-19 should ideally not be treated on a routine dental practice setting and should be referred to an Urgent Dental Care hub (UDC) or similar emergency dental service that is appropriately set up for this purpose. During the outbreak, dental practices are recommended to perform pre-check triages to measure and record the temperature of every staff and patient routinely (4). Patients that are shielding or that are considered higher risk should be seen as early in the clinical session as possible. Longer appointment slots should be allowed to ensure the appropriate time for the infection control protocols to take place and to minimize chances of cross-infection. Patient management: During the COVID-19 outbreak, it may be beneficial for patients to wait in a personal vehicle or outside the dental facility where they can communicate their arrival via mobile phone and be contacted when it is their turn for dental care (61). If feasible, should patients need to wait in the premises they should be seated in a separate, well-ventilated area, at a safe distance (at least 6 ft / 1.80 m apart) and ideally not facing each other (54, 64, 65) . Objects or products that may harbour the virus (i.e. magazines, coffee cups, flower pots, toys) should be removed from the area. The usage of information collection mechanisms, such as medical history or registration forms, pens and clinipads should be limited and they should be regularly disinfected with appropriate stringent surface disinfection techniques. Patients should ideally attend for their appointments alone and be advised not to bring accompanying friends and family members unless strictly necessary (64). The usage of a surgical mask, the preservation of social distance and following strict respiratory hygiene (i.e. covering mouth and nose with a tissue before coughing or sneezing followed by its adequate discarding) should be strongly recommended and ideally stressed to patients prior to attendance (66). The installation of physical barriers such as glass or plastic screens at reception areas can also be beneficial to prevent cross-infection (61) Hand hygiene: During their training, healthcare professionals are taught the importance of hand hygiene and how it plays an integral part of preventing infection in clinical practice. The literature states that hand hygiene is considered the most critical measure to minimize the risk of transmitting pathogens in dental settings and reduce nosocomial infections (67). Due to the possible transmission routes of SARS-CoV-2 this routine pre-requisite is crucial to avoid the transmission of the disease in dental settings (59) . The usage of hand-sanitizers or antiseptics before and after the dental procedure is strongly advised for all dental professionals and patients, preferably delivered through a sensor-detected, non-touch system (53, 64, 68, 69). Surface disinfection: This highly infectious pathogen can persist on surfaces from some hours up to several days (59, 70) . This underpins the need for good hand hygiene and the importance of thorough disinfection of all relevant surfaces within the dental practice between patients using hospital-grade disinfectants (i.e. ethanol 70%). If there is a shortage of hospital-grade disinfectants, surface decontamination may be performed with 0.1% sodium hypochlorite after cleaning with a neutral detergent, although the effectiveness of this approach against SARS-CoV-2 is not absolutely certain (65). The communal areas and public facilities must be cleaned and disinfected on a regular basis, which will include total disinfection of all door handles, chairs, desks, touch screens and monitors. Personal Protective Equipment (PPE): As a part of source control efforts, dental professionals should wear a cloth face covering or facemask at all times whilst they are in the dental setting (61). SARS-CoV-2 is ‗aerosol-transmissible' and this has significant implications on how the dental team should manage possibly infected patients and what sort of PPE they are required to wear. Dental clinical professionals typically use face masks and/or visors, however, it is questionable whether the protection provided by these PPE acts as an efficient protective barrier for aerosols (51) . Furthermore, often these equipments do not fit perfectly or are placed/removed inadequately in clinical practice (51) . The usage of disposable PPE and devices such as mouth mirrors, syringes, masks, gloves, long-sleeved gowns and goggles or face shields/visors, is recommended to protect skin and mucosa from potentially infected blood or saliva and to prevent cross-contamination during the COVID-19 outbreak (8, 54) . Since respiratory droplets are the main route of transmission of SARS-CoV-2, adequately fitting particulate respirators (i.e. N-95 masksas authenticated by Chinese health authorities or FFP2/FFP3-standard masksas set by the EU) are recommended for dental professionals treating patients during the outbreak of COVID-19. A diagram of suggested PPE for dental clinical staff in direct contact with potential COVID-19 patients is displayed on Fig. 3 . It is essential that all clinical and non-clinical dental professionals are appropriately trained on the adequate usage of PPE, particularly which PPE is needed for each circumstance and how to proceed with safe donning and doffing practices. Air management: Patients with suspected or confirmed infection by SARS-CoV-2 should ideally be treated in negative pressure treatment rooms / air-borne infection isolation rooms (AIIRs) (66). The usage of high volume suction is indispensable to remove potential infectious droplets and aerosols at their source, as soon as they are emitted, minimizing or preventing their dispersion in the air. The cleaning of the filters of the suction apparatus should be performed regularly to ensure their effectiveness and, to prevent the recirculation of potentially contaminated air, the exhaust air should be vented outside (71). Medical Waste: The management of medical and domestic waste produced following the treatment of suspected or confirmed patients infected with SARS-CoV-2 should be treated as infectious clinical waste category B (59, 65) . Therefore, double-layer yellow colour medical waste package bags and -gooseneck‖ ligation are advised and handled by staff with appropriate PPE. The surface of the package bags should be clearly marked and disposed in accordance with the healthcare facility policies and local regulations (65,72). Preprocedural mouthrinses (PPMR): There is no published evidence regarding the clinical effectiveness of PPMR to reduce SARS-CoV-2 viral load in saliva or to prevent the transmission of COVID-19 (61). Some of the literature seems to suggest that the usage of PPMR may reduce the amount of pathogens intraorally prior to a dental examination and therefore this may be advantageous during the COVID-19 outbreak (73, 74) . Yoon et al. in May 2020 reported that mask wearing, hand washing and Chlorhexidine PPMR could be beneficial in controlling droplet transmission and SARS-CoV-2 transmission (75). Since coronaviruses are vulnerable to oxidation, PPMR with oxidative agents such as 0.2% povidone or 1% hydrogen peroxide can potentially decrease the viral load of this pathogen in the oral cavity and therefore reduce the risk of infection for patients and dental professionals (59). Oral examination: Some dental procedures have a higher risk of causing patients to cough and consequently produce potentially infectious droplets in the process. Therefore, clinicians should be mindful of this fact and try to avoid such procedures, perform them with extra caution or try and find feasible alternatives. Peri-apical or bite-wing intra-oral x-rays are frequently used in dental examinations, however they often cause an increase on saliva production and can potentially cause patients to cough due to the position of the radiographic holders (76). Therefore, extra-oral dental imaging alternatives like panoramic images, oblique lateral views, as well as, cone beam computed topographies (CBCT), should be regarded as appropriate substitutes during the outbreak of COVID-19 (72). When intra-oral x-rays are required, it is prudent to consider having a double protecting barrier on the sensors in order to avoid perforation and prevent cross-contamination (77). Examination procedures that are likely to generate aerosols such as the usage of a 3-1 syringe, should be reduced as much as possible. (76) Aerosol-Generating procedures (AGP): AGP should be avoided whenever possible and minimally invasive/atraumatic restorative techniques should be preferred. If aerosol-generating procedures are necessary for dental care, the usage of four-handed dentistry, adequate PPE, high volume suction and dental dams is advised to minimize droplet spatter and the production aerosols (61,62, 79) . Ideally, dental treatment should be provided in individual patient rooms whenever possible and if AGP were performed it is recommended the room is left vacant for a period of time before cleaning is carried out (80). The rate of clearance of aerosols in an enclosed space is dependent on the extent of any mechanical or natural ventilation and the size of the droplets createdthe greater the number of air changes per hour (ventilation rate), the sooner any aerosol will be cleared. (80) Rubber Dam: The usage of rubber dams is a widely used isolation technique that has been proven to have a significant effect on the control of moisture during dental treatments (78). The literature states that this technique can reduce the production of potentially contaminated saliva and aerosols, therefore minimizing the risk of crosscontamination by SARS-CoV-2 when using high-speed dental hand-pieces or ultrasonic devices. (78). The British Endodontist Society (BES) has issued, on their most recent guidelines that, during the outbreak of COVID-19, it may be beneficialif feasible -to position the rubber dam so that it covers the nose of the patient (AAE position paper) to minimize the risk of inhalation of pathogens (81). Anti-retraction: High-speed dental hand-pieces are commonly used in every day dental procedures and their sterilization is mandatory. These rotational tools can aspirate and expel debris and fluids during treatments and potentially cause crossinfection by causing a backflow of pathogens that can affect the hand-piece but also the dental unit. Using hand-pieces with anti-retraction valves or other anti-reflux designs can minimize this risk of cross-infection significantly. Therefore, these should be a preferred option for dental treatments during the COVID-19 outbreak (59, 82) . Endodontic emergencies: According to the latest BES guidelines, during the COVID-19 pandemic, patients that present symptomatic irreversible pulpitis, symptomatic apical periodontitis or acute apical abscess and, where appropriate analgesia was not effective, may require emergency endodontic treatment (81). If the tooth is predictably restorable this can be performed with chemo-mechanical caries removal, following rubber dam isolation and using high-volume suction after local anaesthesia. The extirpation of the dental pulp should then be executed to alleviate the pain (8) . The BES is currently advising not to perform the instrumentation of the root canal system but rather access into the pulp chamber only for risk management purposes. The usage of NaOCl as irrigation (higher concentrations are indicated as they are more effective in dissolving pulp tissue) and of a steroid containing dressing material (i.e. Odontopaste or Ledermix) or CaOH2 as dressing as indicated, prior to the restoration with a temporary filling is recommended (81). The root filling procedure could be performed at a later stage if feasible and indicated. Trauma: The clinical decision of treating tooth fracture, luxation or avulsion should be assessed individually. Factors such as the age of the patient, the severity of the dental injury, the stage of apical development and the duration of tooth avulsion should be carefully taken into consideration before proceeding with treatment. (83, 84, 85) . Certain occurrences such as dento-alveolar trauma or progressive fascial space infection will most certainly demand emergency treatment (54) . Surgical emergencies: If a tooth needs extraction and if the soft tissue closure demands suturing for an adequate haemostasis and better post-operative healing, the usage of absorbable sutures should be preferred. Similarly, for patients with facial soft tissue contusion, debridement, followed by suturing with absorbable sutures (if feasible) should be performed. It is recommended to carefully rinse the wound whilst using high volume suction to avoid spraying. Potentially life-threatening circumstances when oral and maxillofacial compound injuries are suspected, should be referred to hospital straightaway (8). Even though a systematic search of the existing literature was performed, this is not a systematic review. Furthermore, it should be understood that the information presented is based on the best available evidence at the time this review was written. At the time of publishing there was still a vast range of uncertainty in regards to the true magnitude and impact of the COVID-19 outbreak worldwide. In light of this, it is challenging and perhaps over ambitious to objectively reach any conclusive results on the implications of this viral outbreak in the present and future of dentistry. In a fast-moving situation like this any information risks being outdated, and represents a significant limitation to the present review. It is beyond the scope of this article to provide absolute guidance for an active practice setting, but rather to clarify the current knowledge of COVID-19, the challenges posed to dental professionals and suggest possible management and protective protocols. The literature suggests that further precautions are necessary in dental practice, including careful pre-screening of patients, adequate referral for dedicated services if applicable and additional and strict protective infection control measures if treatment of patients with confirmed or suspected COVID-19 is considered necessary. There is a generalised consensus recommending dentists to defer elective dental treatment during the outbreak of the pandemic and to focus only on emergency care. Dental professionals should be mindful that COVID-19 case presentations can be dynamic, and there is a good chance that dental practices may have to treat asymptomatic patients, since the incubation period can range from 2-14 days and most patients only develop mild symptoms (31, 43) . Consequently, every patient should be regarded as potentially infected and all dental care services need to rethink their infection control protocols and their systems of triaging, booking and treating patients. (58, 80 ). In the current scenario of outbreaks, epidemics, endemics and pandemics, the concept of multi-professional, interdisciplinary and trans-disciplinary action is of utmost importance. The participation of dentistry, oral medicine and pathology are essential for the better understanding, diagnosis and management of COVID-19 patients and to prevent the dissemination of this pandemic as well as the serious consequences to health services and economies worldwide. This new emerging COVID-19 threat could eventually become a less pathogenic and more common infection in the worldwide population. Indeed, it is predicted to persevere in our population as a less virulent infection with milder symptoms, if it follows the same evolutionary pattern of other human coronavirus infections (i.e. SARS-CoV and MERS-CoV) (54) . Therefore, it is imperative to make informed clinical decisions, educate the public to prevent panic, while promoting the oral health and general wellbeing of patients during these unprecedented times. The prudent practitioner will use this review as a starting point and continue to pro-actively update themselves with trusted online information as the outbreak of COVID-19 continues (54), (Table 3) . Throughout the world it has been inspiring to see how dental professionals have united resources whilst complying with the strict limitations advised by governments and the WHO: dental practices have made any stock of PPE available to the frontline healthcare services; 3D printing dental workflows have creatively been employed for the production of masks, visors and even ventilator components; many dental professionals have facilitated continued professional education remotely, and many have volunteered to be in the frontline treating COVID-19 patients. The authors would like, as a conclusive note, to use these inspirational examples as a hopeful tone to anticipate what lies ahead for the future of dentistry after the COVID-19 outbreak. Table 1 -Non-exhaustive risk assessment factors for consideration during the COVID-19 outbreak Table 2 -Summary of management protocols and protection for the dental team during the COVID-19 outbreak Table 3 -Suggested websites for updated COVID-19 numbers European Oral Microbiology Workshop (EOMW) 2011. Healthcare-associated viral and bacterial infections in dentistry The Novel Coronavirus Originating in Wuhan, China: Challenges for Global Health Governance China coronavirus: WHO declares international emergency as death toll exceeds The species Severe acute respiratory syndrome-related coronavirus: classifying 2019-nCoV and naming it SARS-CoV-2. Nat Microbiol 2020. 12 -Fehr AR, Perlman S. Coronaviruses: An Overview of Their Replication and Pathogenesis Coronaviruses: severe acute respiratory syndrome coronavirus and Middle East respiratory syndrome coronavirus in travelers A pneumonia outbreak associated with a new coronavirus of probable bat origin Identification of a pangolin niche for a 2019-nCoV-like coronavirus through an extensive meta-metagenomic search Single-cell RNA-seq data analysis on the receptor ACE2 expression reveals the potential risk of different human organs vulnerable to 2019-nCoV infection Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China Clinical characteristics of 138 hospitalized patients with 2019 novel coronavirus-infected pneumonia in Wuhan, China Epidemiological and clinical characteristics of 99 cases of 2019 novel coronavirus pneumonia in Wuhan, China: a descriptive study Characteristics of and important lessons from the coronavirus disease 2019 (COVID-19) outbreak in China: summary of a report of 72 314 cases from the Chinese center for disease control and prevention 25 -Coronavirus disease 2019 (COVID-19) pandemic: increased transmission in the EU/EEA and the UK -seventh update Emerging novel coronavirus (2019-nCoV)-current scenario, evolutionary perspective based on genome analysis and recent developments Clinical characteristics of novel coronavirus cases in tertiary hospitals in Hubei province Epidemiological and clinical features of the 2019 novel coronavirus outbreak in China. medRxiv 2020. 29. World Health Organization-WHO (2020a) Updated Country Preparedness and Response Status for COVID-19 as of Genome composition and divergence of the novel coronavirus (COVID-19) originating in China National Health Commission of China. 2020a. The diagnosis and treatment protocol for novel coronavirus pneumonia Isolation of infectious Zika virus from saliva and prolonged viral RNA shedding in a traveller returning from the Dominican Republic to Italy Postnatal identification of zika virus peptides from saliva Human Saliva: Non-Invasive Fluid for Detecting Novel Coronavirus (2019-nCoV) Trained immunity: a program of innate immune memory in health and disease Microneedle array delivered recombinant coronavirus vaccines: Immunogenicity and rapid translational development. EBioMedicine Incubation period of 2019 novel coronavirus (2019-nCoV) infections among travellers from Wuhan, China Transmission of 2019-nCoV Infection from an Asymptomatic Contact in Germany Clinical characteristics and intrauterine vertical transmission potential of COVID-19 infection in nine pregnant women: a retrospective review of medical records Lancet Transmission Routes and Infection Control of Novel Coronavirus-2019 in Dental Clinics -A Review Recognition of aerosol transmission of infectious agents: a commentary Virological assessment of hospitalized patients with COVID-2019 COVID-19): Implications for Clinical Dental Care Persistence of coronaviruses on inanimate surfaces and its inactivation with biocidal agents Exhaled droplets due to talking and coughing Epithelial Cells Lining Salivary Gland Ducts Are Early Target Cells of Severe Acute Respiratory Syndrome Coronavirus Infection in the Upper Respiratory Tracts of Rhesus Macaques Transmission of SARS and MERS coronaviruses and influenza virus in healthcare settings: the possible role of dry surface contamination Guidance for Dental Settings -Interim Infection Prevention and Control Guidance for Dental Settings During the COVID-19 Response 65 -European Centre for Disease Prevention and Control. Infection prevention and control for COVID-19 in healthcare settings -Third update International Association of Dental Traumatology guidelines for the management of traumatic dental injuries: 1. Fractures and luxations of permanent teeth Acknowledgment: The authors would like to thank the WHO for making the COVID-19 data available and also to Dr. José Teles for providing insight and comments on the manuscript before submission.