DISCUSSION

The relevance of this article is related to the proportion taken by the COVID-19 pandemic and at the greater risk of infection by the dental personnel.^{Reference Kowalski, Sanabria and Ridge15} The results revealed that at least 3 of the main symptoms associated with COVID-19 (dry cough, shortness of breath, and high fever) were well-known to dentists in the primary and secondary levels of care. However, other symptoms, such as headache, muscle pain, and sore throat were comparatively lesser known to them. Our results also showed no relationship between the knowledge of COVID-19 symptoms and execution of dental treatment, either urgent or elective, during the pandemic. It is not clear whether there is a relation between this knowledge and safer treatment care during the COVID-19 pandemic. However, in the case of other viral infections, such as hepatitis B, hepatitis C, and HIV/AIDS, it has been demonstrated that dentists’ level of knowledge of a disease plays a particularly important role in forming their attitudes and practices regarding patients.^{Reference Rostamzadeh, Afkhamzadeh and Afrooz16}

The infection of salivary glands by coronavirus is being given increasing importance and attention in recent studies, in which the potential diagnosis of COVID-19 in saliva is revealed,^{Reference Sri Santosh, Parmar and Anand17} as well as its connection with the development of asymptomatic infections.^{Reference Xu, Li and Gan18} Ren et al.^{Reference Gamio19} reported that loss of taste is an early symptom of COVID-19. The fact that this symptom appears before fever and other common symptoms of COVID-19 supports the hypothesis that the oral cavity, especially the mucosa of the tongue, may be an initial site of infection for SARS-CoV-2.^{Reference Gamio19} According to The New York Times, dentists are at the greatest risk of infection,^{Reference Lui, Wong and Sanchez-Luna20} since they work directly with salivary fluids in the form of aerosols, which have a great potential for viral transmission.^{Reference Ren, Rasubala, Malmstrom and Eliav21} This places the dentist community, especially the ones in primary health care, in an extremely vulnerable position, as they are the frontline oral health care professionals caring for patients, some of whom may be asymptomatic. This calls for greater preparation, including more protective barriers for the safety of these individuals while they perform their work.

Almost all dentists who participated in this study agreed that COVID-19 can be transmitted during dental treatment. However, the results on the biosecurity measures highlight an important concern. While dentists who considered their PPE and biosafety procedures to be sufficient in preventing COVID-19 infection were more prone to perform urgent and elective dental care, a high percentage of professionals believed that the current biosecurity measures and routinely used PPE are not sufficient to prevent COVID-19 infection. It is not clear whether this high percentage is due to a low level of preventive methods being used in primary and secondary dental care, or due to the professionals’ lack of knowledge regarding biosecurity and clinically safe practices during the pandemic. Most likely, they did not have access to protocols and reliable guidelines to improve their knowledge in this area. Despite not being universally accepted, there are reliable research articles describing preventive measures in the dental setting.^{Reference Peng, Xu and Li10,Reference Yang, Soh and Cai22} These articles describe in detail some practical strategies to block virus transmission, such as patient evaluation, hand hygiene, personal protective measures, rinsing the mouth before any dental procedures, rubber dam isolation, disinfection of the clinic settings, and management of medical waste. However, the scientific information does not seem to be flowing to all dentists at the desired speed. It remains in the personal interest to seek for most of this information, and the scientific method is probably not dominated by most professionals. Therefore, it is important to have a leadership in the dissemination of adequate information during a pandemic, as the overload and the uncertainties caused by confused and contradictory articles may disorient rather than clarify the biosecurity and PPE methods that must be used.^{Reference Correia, Ramos and Bahten23} Public policies are extremely important in the dissemination of proper information. On that manner, SUS has played an important role in responding to the disease, with initiatives to improve its capacity and with the establishment of specific protocols for the clinical management of patients, and a good control on the community transmission of COVID-19.²⁴ However, a protocol for dental treatment is yet to be established. Additionally, as the primary health care system is run by the municipalities, some differences may be seen as the implementation of COVID-19 preventive measures in different parts of the country, which is also influenced by the financial challenges faced, and the availability of supplies. Additionally, as Brazil is a highly populated country with an extended continental territory, individual state governors are enforcing social distancing measures based on the number of cases and intensive care unit occupancy rates in public and private hospitals.²⁵ Differences in the rules of social isolation among the various regions of the country may be influencing social isolation/distancing and the provision of elective and urgent care to some extent.

A study carried out among Jordanian dentists working in various levels of care corroborates with our findings and the findings of another study.^{Reference Correia, Ramos and Bahten23,Reference Khader, Al Nsour and Al-Batayneh26} It establishes that dentists are aware of COVID-19 symptoms, mode of transmission, infection controls, and measures in dental clinics. However, many dental practices lack the minimum requirements for infection control, despite the availability of prevention guidelines.

We observed an evident incompatibility between knowledge of COVID-19 symptoms and social isolation/distancing. One would assume that the higher the knowledge, higher would be the adherence to social isolation/distancing. However, the present study revealed that this was not true. This can largely be attributed to the fact that dental professionals working in public primary and secondary health care services are considered essential and, therefore, cannot stop working. Generally, in Brazil, dentists undergo exams to enter the public service in Brazil, which may reflect this higher knowledge among those not maintaining social distancing. Nevertheless, this is only a supposition, as the data collected are not sufficient to test this hypothesis.

An important finding of the present study is that a considerable percentage of the study population was carrying out dental procedures other than emergencies, despite not believing that the biosafety care protocols were sufficient. This poses a real risk of cross-infection and COVID-19 dissemination, especially since there is not yet a universal protocol or guideline available regarding dental care for active or suspected COVID-19 cases.^{Reference Alharbi, Alharbi and Alqaidi27} Nevertheless, as occurred with other viral infections, such as HIV/AIDS, international accepted guidelines/protocols, as well as the technological development of preventive tools, need to be prepared to deal with the COVID-19 challenges.

Professionals who graduated recently (0-5 years) were more poorly informed on COVID-19 symptoms than the other groups. This finding corroborates with the study of Rostamzadeh et al., which deals with other viral infections and obtained a lower level of knowledge in recent graduates.^{Reference Ren, Rasubala, Malmstrom and Eliav21} The higher knowledge may be due to clinical experience or postgraduate courses. This is further supported by a recent study on dentists’ knowledge of COVID-19, which found that professionals with higher qualifications (postgraduates) reported better knowledge scores as compared with recent graduates.^{Reference Kamate, Sharma and Thakar28}

It is unavoidable to discuss that post-pandemic, the cost of dental treatment will probably increase. New treatment protocols in the patient-dentist relationship might also be needed, especially in the case of pediatric and special-needs patients. The SUS is financed by the public government, and, despite its importance in providing health care to the Brazilian population, it has been suffering from insufficient funding for a long time.^{Reference Castro, Massuda and Almeida29} After the acute COVID-19 pandemic, the need for implementation of additional preventive measures during dental treatment will add to the financial stress on primary public health service and may interfere with the amount and diversity of treatments offered. Management of pediatric and special-needs patients quite often demand close contact with the dentist. Commonly, this involves interactions without dental masks and PPE before the dental treatment itself, in order to familiarize the patient with the dental environment and personnel, which is fundamental in the patient-dentist bond and allows for less traumatic and better quality treatment. The additional preventive barriers, which are necessary to prevent the COVID-19 infection, might interfere with this interaction and, therefore, make dental treatment complex.