The term “aerosol” in the dental environment was first used by Micik and colleagues.14 Aerosols are defined as particles less than 50 micrometers in diameter.14 They are capable enough to stay airborne for an extended period before they settle on environmental surfaces or enter the respiratory tract. The even smaller particles of an aerosol (i.e., 0.5 to 10 µm in diameter) have the potential to penetrate and lodge in the smaller passages of the lungs which are thought to carry the greatest potential for transmitting infections. Bio-aerosols on the other hand are aerosols that contain particles of any kind of organism.15 In the context of the COVID-19 pandemic, the awareness of aerosol-related transmission among dentists becomes more relevant which is the basis for this study.
Sources of bio-aerosols in dental setups are ultrasonic scalers, high-speed handpieces, air turbines, three in one syringe, and air-water syringes.16 The majority of the participants of this study knew about the dental procedures generating aerosol and 13% of them even believed that simple extraction and hand scaling generate aerosol. The highly contagious nature of the COVID-19 might have led the dentists to be skeptical for each dental procedure as an aerosol-generating procedure. A similar finding was observed by Teja et al,13 where they reported that 60% of the participants felt that restorative procedures and any procedures producing aerosols have higher chances to transmit COVID-19 and 35% of them felt that surgical procedures have higher chances of the transmission of infection.13
A total of 230 (60%) respondents were practicing only emergency dental services during the pandemic which is in accordance with CDC guidelines which states that non-emergency dental procedures should be postponed.8 In a study, done among Turkish dentists 49.95% avoided performing aerosol-forming procedures as much as possible.17 CDC states that emergency dental procedures like emergency access opening of acute pulpitis case with a dental handpiece can be the source of virus transmission to operatory and dental professionals with aerosol generation.8 A recent systematic review even recommends lower power settings be considered to reduce the amount and spread of contamination during the operative procedures.18 This highlights the importance of taking precautions to avoid any airborne contamination in a dental operatory.
Majority of the participants, 43.3% of this study utilized social media to get updated with the information related to COVID-19 which is higher as compared to the study done by Kamate et al.12 They observed that the source of information regarding COVID-19 was primarily the internet (37.7%). This shows the increased use of social media during the lockdown period.
A total of 296 (77%) participants in this study were aware that particles may enter through the route between mask/eyewear and facial skin. This awareness can be the result of following recent CDC guidelines by the dentist of Nepal which states that protective eyewear (e.g., safety glasses, trauma glasses) with gaps between glasses and the face likely do not protect eyes from all splashes and sprays.8
More than 82% of the respondents of the current study agreed that high-efficiency particulate air (HEPA) filter along with high volume evacuator should be used to reduce the airborne contamination. SARS CoV-2 can remain viable in aerosol and survive up to 3 days on inanimate surfaces at room temperature, with a greater preference for humid conditions.19 Dental patients and dental health care professionals (DHCPs) and other persons not directly involved in patient care but potentially exposed to infectious agents like administrative, clerical, housekeeping, maintenance, or volunteer personnel can be exposed to pathogenic microorganisms.11
Particulate respirators (e.g. N-95 masks authenticated by the National Institute for Occupational Safety and Health or FFP2-standard masks set by the European Union) are usually recommended for a routine dental practice.20 The majority of the respondents (82%) of the current study agreed that N90/ N-95 mask should be routinely worn in dental practice due to the current outbreak. In a study conducted among Indian dentists, revealed that almost 50% of them selected Surgical N95 (medical respirator) as a first option.21 An interesting finding has been reported by Gambarini et al.,22 where 70% of the dentists consider dental settings more dangerous for the diffusion of COVID-19 than other social behaviors (i.e., going to food markets, restaurants, and beauty salons, etc.).
The present study revealed that the mean attitude score for the participants within the age group of 31–40 years was found to be statistically significantly higher than < 31 years. Almost similar findings were noted in a cross-sectional study which showed that Professors/Associate professors were equipped with better knowledge and attitude regarding COVID-19 disease than lecturers23 assuming that the professors would be older than the lecturer.
Regarding the current ventilation system of the operatory, a total of 35 participants were practicing in an air-conditioned room with a closed chamber and 28 of them were not aware of their practice ventilation system of their practice. Swedish government recommends that dental practices can only provide aerosol generating procedures (AGPs) in practice if they have surgical space with external ventilation. The clearance of infectious particles after an AGP is dependent on the ventilation and rate of air change within the room and treatment rooms must be decontaminated after completion of an AGP. The ‘rule of thumb’ below should be followed until further definitive advice is available: a) For a treatment room with more than 10 air changes per hour (ACH) and which can be evidenced to the National Health Service (NHS) Board, a minimum of 20 minutes ‘fallow time’ (after which entrance to the room without PPE is allowed) before cleaning is recommended. b) For a treatment room with external ventilation (natural or mechanical) with less than 10 ACH or with no data on the number of air changes per hour available, the fallow time would be 60 minutes. c) For a treatment room with no external ventilation (natural or mechanical), the absence of air changes means that AGPs should not be undertaken.24
Although, isolation and high-volume suction are effective to reduce ultrafine dental aerosol particles25, airborne Infection Isolation Rooms (AIIRs) should be reserved for patients. Air from these rooms should be extracted directly to the outside or be filtered through a HEPA filter.8
The findings from a systematic review conducted by Kumbargere et al.,26 stated that the use of a high-volume evacuator (HVE) may reduce bacterial contamination in aerosols less than one foot (~ 30 cm) from a patient's mouth but not at longer distances. The participants of the present study who preferred HEPA filter along with UV light and high-volume evacuator in their operatory for the management of participants during this pandemic were 53%. But, none of them reported having installed this system during the study period. This emphasizes the need to modify dental operatory for preventing airborne contamination.
On following dental setups of our colleagues, certain changes in the operatory like installation of high-volume evacuator, modifying the closed air-conditioned operatory to cross-ventilated one, etc. were made in few setups. However, the majority of the dentists were practicing in the existing operatory without any modifications. This may reflect the financial constraint faced by the Nepalese dentist despite being aware of the aerosol-related cross-contamination in the dental clinics which needs serious consideration.