Economic, Health-Care and Teaching-Learning Impact of COVID-19 (SARS-CoV-2) on Dentistry

The aim of this chapter is to look more closely at the impact that the crisis generated by the SARS-CoV-2 is having on health, the economy and education in the field of dentistry. The considerations that must be taken into account in dental practice will be presented, as well as the usefulness that the use of teledentistry (TD) could have in times of pandemic, reflecting on the different specialties of dentistry that can benefit from this modality, as well as the advantages and disadvantages that its use can present. Likewise, teaching has been condemned to a lack of presence, having to resort to distance learning, both synchronous and non-synchronous, which can cause needs and deficiencies in undergraduate and postgraduate students. We will analyse the health risks in the dental field and the changes and needs for safe dentistry in times of pandemic. We will also break down the effect of the crisis on the medical-dental sector and the economy, from the point of view of patients and professionals, especially in times of increased restriction and confinement worldwide.


Introduction
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causal agent of coronavirus disease (COVID- 19), is a 60-140 nm single-stranded RNA virus that belongs to the genus β-Coronavirus, has a corona appearance because of the presence of glycoproteins in the envelope, and it is substantially different genetically from MERS-Cov but similar to SARS-CoV [1]. It can be transmitted between humans and its intermediate host is still under investigation [2]. The Covid-19 pandemic has caused huge changes in all fields, including dentistry.
It is known that several viruses, such as herpes simplex virus, cytomegalovirus and Zika are transmitted through saliva and are able to infect and replicate in the oral mucosa, causing painful ulcers. Currently some authors have reported oral manifestations of COVID-19 disease [3]. These can have a variety of clinical presentations, presumably supporting the hypothesis of thrombus formation and vasculitis [4]. These include necrotic ulcers and aphthous ulcerations that develop early in the course of the disease, as well as dysgeusia. Awareness of these oral manifestations is important because lesions may precede typical respiratory symptoms by several days, and worsening oral lesions may precede a more severe clinical scenario [3].
Saliva from asymptomatic persons with COVID-19 has also been observed to have potential for viral transmission and a positive correlation between salivary viral load and loss of taste [5]. SARS-CoV-2 utilises host entry factors, such as members of the ACE2 (angiotensin-converting enzyme, the major host cell receptor of SARS-CoV-2) and TMPRSS (TMPRSS2 and TMPRSS4) family that have been expressed in salivary glands and oral mucosal epithelia [5,6]. These data demonstrate that the oral cavity is an important site for SARS-CoV-2 infection and implicate saliva as a possible route of SARS-CoV-2 transmission.
In addition, it is considered that some oral diseases could be exacerbated by COVID-19, especially those of autoimmune aetiology, as these are related to a compromised immune system or long-term pharmacotherapy, [7], which indicates that we should pay special attention to the dental care of these patients. Patients with oral psychosomatic illnesses are more susceptible to stress and this could be exacerbated in the current pandemic situation, so they may need emergency consultations and psychological counselling. The dentist must provide comprehensive care to patients and to this end, teleconsultation may be useful. [8].
Healthcare workers have a higher rate of exposure to the virus (face-to-face interaction, exposure to body fluids such as blood and saliva) which increases the risk of infection, as we try to illustrate in Figure 1. Dental practice presents a potential risk of cross-contamination and staff are at risk of transmission of infections. [9] In this situation, it may be advisable to use teleconsultations. The advantages of teledentistry (TD) during the COVID-19 crisis have been observed through a pilot study, where it was determined that TD allowed a monitoring of all patients, reducing costs and contact, therefore decreasing the risk of COVID-19 spreading [10]. The Australian Dental Association has published the guidelines for TD and it considers that teleconsultation is most suited to patients who require follow up, and, likewise it is very convenient for patients presenting with an acute dental problem that needs to be deal with outside of normal practising hours, for those who are unable to attend the clinic due to illness or quarantine, and for vulnerable patients

Clinical considerations
Dental professionals must examine and detect potential high-risk patients to prevent the dissemination of infectious disease. No routine treatment should be carried out on patients in the early stages of infection [1].

Telephone triage
We will ask the following dichotomous questions over the phone and repeat them when the patient arrives at the clinic.
• Do you have fever or have you had one in the last 14 days (temperature > 37.5°C)?
• Have you had a cough or any other respiratory sign in the last 14 days?
• Have you had or do you have diarrhoea or other digestive problems in the last 14 days?
• Do you have or have you had a feeling of great tiredness or discomfort in the last 14 days?
• Have you noticed a loss of sense of taste or smell in the last 14 days?
• Have you been in contact or living with someone suspected or diagnosed to have coronavirus?
• If so, are you still in quarantine?
In order to make a decision, we must act as follows: • In the case of the 8 negative responses: ○ Patient with more than 37.5° (99.5°F) do not treat unless it is urgent, postpone 14 days to see evolution.
○ Patients with less than 37.5° will be treated with the indicated protocols • At least one affirmative answer ○ Patient with more than 37.5° do not treat except as a matter of urgency ○ Patients with less than 37.5°, it is advisable to postpone the treatments for 14 days.
• If it is an emergency (cellulitis, abscess, haemorrhage, severe trauma...) the patient will be attended under maximum safety conditions.
When the patient is summoned by telephone, he/she must be informed of the recommendations for coming to the clinic: ○ The patient should go alone (unless he/she is a minor or a person in need of help).
○ Bracelets, rings, earrings, watches, etc. should be removed. The patient should arrive at the agreed time and avoid bringing bags and unnecessary personal objects.
○ As soon as the patient arrives, his your temperature will be taken by means of an infrared thermometer, he will be asked to rub his hands with hydroalcoholic gel for 20 seconds and to answer the questionnaire. The patient should maintain a distance of 2 metres if he or she crosses someone and should not wander.
The patient must be made aware of the importance of preventive measures. At the same time, we must convey to him/her the feeling that he/she is in a place where all preventive and safety measures are being followed.

Hand hygiene and personal protective equipment (PPE)
The WHO in 2012 recommends that hand hygiene should be performed before touching a patient, before any cleaning or aseptic procedure, after body fluid exposure risk, after touching a patient and after touching a patient's surroundings [12].
In the dental practice, the spread of micro-organisms is mainly radiated to the dentist's face, specifically to the eyes and around the nose [13] therefore personal protective equipment (PPE) should be used. PPE forms an effective barrier against most of the aerosols generated [14].
Filtering facepiece respirators, also known as disposable respirators, are subject to different rules worldwide. Their use is recommended by dentists as they are continuously exposed to aerosols [15]. Before selecting one, users should consult their local regulations and requirements for respiratory protection.
The standardisation methods used in the different countries are as follows [16]. Under no circumstances should they include an exhalation valve, as in this case the air is exhaled directly into the environment without any retention, favouring the diffusion of the virus We must bear in mind that these should not be sterilised and at most can be disinfected through different methods depending on the type, which will not increase the number of times or time we can use it [17,18]. They should always be used as usual in daily clinical activity. It is recommended to use gloves that protect against viruses (EN ISO 374-5) made of nitrile. For cleaning and disinfection tasks, it is recommended to use thicker, more break-resistant gloves.
• Eye and face protection.
The eye protectors certified according to the UNE-EN 166:2002 standard for protection against liquids can be integral glasses or face shields. They should always be used as COVID-19 can be transmitted through eye contact, as infectious droplets could contaminate the conjunctival epithelium [19].
• Protective clothing, We should avoid using street clothes or shoes in the clinic, avoiding wearing earrings, rings, bracelets, watches and other elements, as they behave as reservoirs of COVID-19.
In Table 1 we can see in what order we should put on and take off the PPE. With the PPE on we must keep our hands away from our face and avoid touching surfaces. When we remove the personal protective equipment, we must disinfect it. PPE must be kept in a proper place and different from the place where we leave our street clothes.

The patient in the cabinet
The patient must pass with the mask on and it will be removed at the time indicated by the professional.

Rinses
During dental practice, it is often difficult to avoid the generation of aerosols, which is why it is important to reduce their viral load. To this end, the preoperative use of antiseptic mouthwashes can be useful. SARS-CoV-2 is vulnerable to oxidation, so a pre-procedure mouthwash with oxidising agents such as 1% hydrogen peroxide or 0.2% povidone was initially suggested [1,9], however, it was recently noted that there is no evidence to support the indication of hydrogen peroxide rinse to reduce viral load of SARS-CoV-2 [20] has highlighted the lack of scientific evidence to support the virucidal activity of hydrogen peroxide rinse, associated with its lack of substantivity and and its indication in dental care protocols should be reviewed [21] . As for povidone-iodine, it can be an effective measure, having demonstrated 99.99% activity when used against enveloped and non-enveloped viruses such as influenza, Ebola, MERS and SARS coronavirus [22], and has strong bactericidal and virucidal properties against pathogens, which cause oral and respiratory tract infections. Regarding chlorhexidine, a rinse often used in dental practice, several studies have suggested that it had little or no effect against the virus compared to other rinses [1,23], but other authors have noted that its use could be beneficial [24].
With regard to Cetylpyridinium chloride (CPC), it could be effective against enveloped viruses such as Sars-Cov 2 [25].

Aerosols
We must bear in mind that any procedure that produces aerosols is potentially risky so high flow suction should be used, as it reduces the dispersion of aerosols, as well as suctioning as close as possible to the treated area. In addition, the cabinet door should remain closed and the cabinet should be aerated between patients.
High-speed rotating instruments must be equipped with an anti-retraction system, which prevents the release of debris and fluids that can accidentally be inhaled during clinical procedures [26]. During the current pandemic, the use of these instruments without an anti-retraction system should be avoided.
The risk of aerosol generation depends very much on the clinical activity performed. The ADA (American Dental Association) classifies the risk into 4 categories:

Rubber dam
One of the easiest and most useful ways to reduce contamination is isolation with rubber dams, especially in those procedures performed with high-speed instruments. This isolation provides a 70% reduction in drops around the surgical field [27]. When its use is not feasible, manual instruments should be used to keep aerosol generation to a minimum [28].

X-rays
X-rays are one of the most commonly used complementary tests. Intraoral x-rays are the most common, however they can stimulate saliva secretion and coughing [26]. Therefore, extraoral x-rays, such as panoramic x-ray and cone beam CT, are suitable alternatives [29].

Disinfection of impressions and prostheses
Before disinfecting it, it must be washed with water. After disinfecting it, rinse it again. The prints made with alginate must be sprayed with 1% sodium hypochlorite for 10 minutes, those made with elastomers (silicones and polyethers) with the same material for 15-20 minutes. Metal-ceramic prostheses and skeletal prostheses should be immersed in alcohol for 5 minutes, acrylics should be immersed in 1% sodium hypochlorite for 10 minutes.
It should be remembered that solutions prepared with sodium hypochlorite have a 24-hour efficacy and should therefore be prepared daily.

Surface disinfection
Human coronaviruses, such as SARS and MERS, can persist on inanimate surfaces for up to 9 days and yet can be efficiently inactivated by surface disinfectants within one minute. Surfaces should be disinfected after each patient visit, especially surfaces near work areas.
Initially Kampf et al. have suggested that 0.5% hydrogen peroxide applied for one minute could be effective against the virus [23] however a study by our group has observed that this is not the case [20] There is no study in the literature demonstrating its effect at this concentration during that time and the authors portrayed themselves shortly afterwards, indicating that their results can only be attributed to 0.5% hydrogen peroxide in an accelerated form [30].

Environmental disinfection
The greatest number of SARS-CoV 2 infections occur in closed spaces, such as the dental cabinet, as the virus can persist viable in the air for hours [31]. Transmission of the virus through aerosols is affected by many factors, such as the physical parameters of the particles, properties of the virus and environmental factors [32]. It has been observed that the aerosols generated in the clinic are kept in the air for 30 minutes and that the procedures that produce the most contamination are those where ultrasound is used [33] and the turbine [34].
In these cases, ventilation is essential to produce a renewal of the air. Ventilation consists of providing outside air to an enclosed space and is a key factor in the elimination of virus-laden air, since it reduces the concentration of the virus and thus reduces the possibility of contagion [35]. It can be done through natural methods, such as opening windows (which has proved effective in the current pandemic [36]) or mechanical methods such as air conditioning and can be complemented by air filtration and disinfection systems.
If natural methods are used, an estimate of the external flow rate must be made in each case as it depends largely on specific local conditions (such as the size of openings and weather conditions). If the temperature in the clinic is unpleasant because it is too low, additional heating methods should be used. In addition, air recirculation should be avoided, as well as overcrowding in the room [35]. Filtration of contaminated air can also be useful, there are different methods, the most used being HEPA [37]. HEPA is an acronym for "High Efficiency Particulate Air Filter" which can remove at least 99.97% of any airborne particles with a size of 0.3 micron (μm), the most penetrating particle size. Particles that are larger or smaller are trapped with even greater efficiency [38]. If filtration systems are used, the manufacturer's maintenance recommendations must be followed.
Different methods have been used to disinfect the air in the current pandemic, including ultraviolet radiation and ozone. Ultraviolet (UV) germicidal radiation can damage microbial DNA and RNA, prevent the reproduction of infectious organisms and reduce the harmful effects they cause [39]. Ultraviolet germicidal irradiation (UVGI) uses UVC radiation to inactivate microorganisms by causing DNA damage and preventing replication. It has been noted that UVC can inactivate coronaviruses [40]. Ozone is a natural gas and an effective environmental sanitation system that provides highly reactive free radicals capable of oxidising bacteria, viruses and organic and inorganic compounds [41].
If there is no natural or artificial ventilation, wait half an hour for the aerosols to settle and then clean the surfaces.

Applications of distance dentistry
Although there is a need to reduce face-to-face visits to decrease the risk of infection, dentists must ensure continuity of care and "teleodontology" or Economic, Health-Care and Teaching-Learning Impact of COVID-19 (SARS-CoV-2) on Dentistry DOI: http://dx.doi.org /10.5772/intechopen.98387 "teledentistry" (TD) is a solution of choice [42]. In periods of pandemic, in many medical specialties as well as in dentistry, teleconsultation can be an effective alternative to office visits in many oral diseases, (as shown in Figure 2) while in a normal setting, this system could be used as a complement.
In the case of patients with COVID-19, or those who suspect they may be infected, TD can assist in remote assessment (triage) and continuity of care. For people who are not infected with the virus, particularly those at higher risk of being affected, TD can provide rapid access to care [43].
Teledentistry (TD) could be described as the combination of telecommunications and dentistry that involves the exchange of clinical information and images over remote distances for dental consultation, diagnosis and treatment planning. There are two main types of teleconsultation: real-time or synchronous and storeand-forward or asynchronous.
Real-time consultation requires a video conference in which the dentist and patient can see, hear and communicate with each other despite being in different locations. The benefit of the real-time consultation format is that information is transferred immediately, so patients and dentists are able to interact with each other regarding dental health issues.
The store-and-forward format enables a patient to store data in a local database that is subsequently forwarded to the dentist. In this system the patient's relevant information and images are collected and stored before being reviewed by the dentist at a later stage. After reviewing the information, the dentist is able to present their diagnosis and subsequent treatment plan. This methodology has several advantages over real time telemedicine systems; the most important being the fact that it is not necessary for the patient and the consultant to coincide in time and space, and furthermore, this system makes it possible for the technological and organisational difficulties that are commonplace during consultations via videoconference to be avoided. It also allows for a greater number of patients to be evaluated per session, and it is also cost-effective as it makes use of already-existing elements, such as e-mail and the upcoming digitalisation of radiology in the hospital.
There is a growing interest in adopting telemedicine systems given that these contribute to the reduction of inequalities in health care [44]. In general, TD can be a useful tool in practically all fields of dentistry, especially during a pandemic in which social distancing is of the utmost importance, given that it saves time for both the patients and the health-care practitioner and it is also more cost-effective.

SARS-CoV-2 Origin and COVID-19 Pandemic Across the Globe
Although visits to the dental surgery are still necessary for many procedures, TD opens new horizons for the diagnosis, treatment and follow-up of many patients, as we can see in Table 2.
In almost all of the fields, referrals by teleconsultation are considered very useful in reducing other unnecessary referrals. Several studies have shown that telemedicine consultations are as reliable as those performed by traditional methods [45].
Teleconsultation offers many advantages, including it can reduce a patient's dental anxiety, which can be important for people who have an irrational fear of dentists, for children and for patients with special needs. Although it also has limitations (Table 3), its use is widespread and there are a growing number of applications for mobile phones and videoconferencing programmes being developed for this purpose. In general, the perceptions of professionals and patients are positive, although in many cases they receive limited training about this technology.

Education
This pandemic has also led to changes in education all over the world due to the social distancing measures. The impact of the COVID-19 pandemic greatly affected dental education, with smart technology showing certain benefits in the learning process [46]. The training of future health science professionals is changing thanks to this digital age. Mariño    most was education [47]. It can be an excellent tool for dentistry students, keeping dentists continuously updated. E-learning offers advantages for students such as eliminating travel time and encouraging student-teacher interactions. Online education connects students and teachers geographically, making the university more universal and accessible [28,48]. Some disadvantages of online courses for the student may include a sense of isolation and difficulty in adjusting, and may also lead to misperceptions and misunderstandings between students and teachers [49]. Although these virtual tools were previously available, their use and exploitation in the Covid-19 crisis has changed substantially. Recent studies confirm that training based on digital tools can improve the learning and clinical decision-making skills of dental students [50][51][52][53] especially in the pre-clinical setting [54]. According to Mardani et al. [55], in a study among dental students divided into virtual (intervention) and face-toface (control) training, the mean clinical decision-making score in the intervention group was higher than the control group (p < 0.001), indicating that the application of virtual patient-based training can enhance students´ skills.
In a previous study carried out by the group studied the perceptions of teachers in Galicia, Spain with regards to online teaching, it was observed that prior to the Covid-19 crisis, 49.2% of teachers did not use any of the available online tools, but as a result of this health crisis their usage has increased [56]. However, the synchronous method is seldom used.
It can also be used for teaching patients. The effectiveness of a mobile phone app in educating mothers of children aged below 6 years of age about oral hygiene has also been studied, and it was discovered that using this app significantly improves the knowledge of mothers towards their child's oral health [57].

Health and economic impact
In Beijing, China, 2,537 participants evaluated how the pandemic influenced the use of emergency dental services and noted that the distribution of dental problems has varied significantly. Oral infections increased from 51.0% before COVID-19 to 71.9% during COVID-19, and injuries decreased from 14.2% to 10.5%. Meanwhile, non-urgent cases decreased to three tenths of pre-COVID-19 cases [58].
Costs of dental care may increase in the future for a number of reasons, including the need for additional resources such as personal protective equipment, changes in dental practice and the fact that the number of patients we will be able to see each day will decrease due to the measures taken. There may also be an increased demand for electronic consultations in the near future [59].
A study of 400 dentists in Galicia, Spain to determine the economic and health impact of SARS-CoV-2 found that the economic impact appeared to be greater for male participants than for female participants (OR = 3,121, p < 0.001). These losses appear to have contributed to the requests for financial support, with 29.5% of respondents who requested financial support recording losses of more than 15,000 euros. The number of patients treated was reduced, although it was noted that more urgent patients were seen per week in the public sector than in private clinics. In terms of health, only four professionals tested positive [60].
To date, we have not found any other document that addresses the economic impact of COVID-19 in dentistry, however, the impact on patient loss and income from SARS CoV-1 in Taiwan has been studied between 2000 and 2003. Significant reductions in dental care (16.7%) have been observed, so fears of COVID-19 significantly affected people's care-seeking behaviour and this fear compromised their accessibility to quality care [61].
Anxiety and fear of becoming infected with COVID-19 among dentists has also been studied in a cross-sectional study with 669 participants from different countries around the world. More than two-thirds were found to be frightened by the effects of the virus and 90% were aware of recent changes in treatment protocols. Dentists around the world, despite their high level of knowledge, are in a state of fear while working due to the impact of the virus [62]. A multi-country study found that in general, most dentists had good knowledge and practice scores with respect to SARS-CoV-2 [63]. As fear among the population to visit dentists after the outbreak of COVID-19 could decrease the demand for conservative dental treatment and increase emergency treatment [59].

Conclusions
The SARS-CoV-2 virus outbreak has had many immediate complications for dentistry, some of which may have more long-term repercussions in the clinic. COVID-19 forces oral health care personnel to understand the implications of the outbreak in their clinical setting and to be aware of possible changes and updates to protocols. New approaches such as teleconsultation could be very useful. Teledentistry will help to assist patients without the need for contact, reducing consultation time and costs. Modern forms of online information-based education have also seen increased use during the current pandemic. Negative oral health and economic impacts have been observed in the dental sector, however more global studies are needed to examine the health and economic impact that the virus is having on both public and private dental clinics.

Conflict of interest
The authors declared that there is no conflict of interest.