Sources of SARS-CoV-2 and Other Microorganisms in Dental Aerosols

Propagation and evaporation of contaminated droplets, emission and exposure in surgery environments revealed by laser visualization and numerical characterization

The contaminated liquid mixture containing mucosalivary fluid and blood would be aerosolized during medical procedures, resulting in higher-risk exposures. The novelty of this research is integrating laser visualization and numerical characterization to assess the propagation and evaporation of contaminated droplets, and the interactive effects of humidity and temperature on exposure risks will be numerically evaluated in surgery environments. The numerical model evidenced by experiments can predict the mass balance of ejection droplets, the minimum required fallow time (FT) between appointments, and the disinfection region of greatest concern. Around 98.4 % of the ejection droplet mass will be removed after the cessation of ultrasonic scaling, while the initial droplet size smaller than 72.6μm will dehydrate and become airborne. The FT recommendation of 30 min is not over-cautious, and the extended FT (range of 28-37 min) should be instituted for low temperature (20.5 °C) and high humidity levels (60 %RH). The variation of the temperature and humidity in the range for human thermal comfort has little influence on the area of the disinfection region (0.15m2) and the cut-off size (72.6μm) of droplet deposition and suspension. This research can provide scientific evidence for the guidelines of environmental conditions in surgery rooms.

Risk of SARS-CoV-2 infection in dental healthcare workers - a systematic review and meta-analysis

Background

Mounting evidence supports an association between the use of personal protective equipment (PPE) and the risk of infection from the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in dental healthcare workers (DCW). However, the prevalence and incidence of SARS-CoV-2 infections in the setting of dental care remains poorly characterized.

Methods

A systematic review and meta-analysis of studies published prior to Mai 2023 providing epidemiological data for the occurrence of SARS-CoV-2 in DCW was performed. A random-effects model was used to calculate pooled estimates and odds ratios (ORs) with corresponding 95% confidence intervals (CIs). The associated factors were narratively evaluated. Risk of bias was assessed using the Joanna Briggs Institute tool for prevalence studies.

Results

Twenty-nine eligible studies were identified including a total of 85,274 DCW at risk; 27 studies met the criteria for the meta-analysis. Among the included DCW, the overall prevalence of SARS-CoV-2 was 11.8% (13,155/85,274; 95%CI, 7.5%-17%), whereby the degree of heterogeneity between the studies was considerable (I2=99.7%). The pooled prevalence rate for dentists and dental hygienists alone was 12.7% (1943/20,860; 95%CI, 8.0%-18.0%), showing significantly increased odds of contracting a SARS-CoV-2 infection compared to dental assistant personnel, the prevalence rate for which was less than half, at 5.2% (613/15,066; OR=2.42; 95% CI, 2.2-2.7). In the subgroup of 17 studies from countries with high income there was a significantly lower prevalence rate of 7.3% (95% CI, 5%-10%) in DCW compared to the prevalence rate in low- and middle-income countries, which came to 20.8% (95% CI, 14%-29%; p<0.001). In 19 out of the 29 studies (65.5%), specific information on the use of and adherence to PPE was absent while in the reports with concrete figures the wearing of N95 (or at least surgical masks) by DCW appeared to be associated with lower SARS-CoV-2 prevalence rates.

Conclusions

DCW were, depending in each case on their proximity to patients, at particular risk of SARS-CoV-2 infection during the COVID-19 pandemic. Until a significant level of vaccination protection against newer SARS-CoV-2 variants can be built up in the population, dental healthcare facilities should further maintain their focus on using PPE according to current guidelines.

Visualization of droplets and aerosols in simulated dental treatments to clarify the effectiveness of oral suction devices

PURPOSE

The hazards of aerosols generated during dental treatments are poorly understood. This study aimed to establish visualization methods, discover conditions for droplets/aerosols generated in simulating dental treatments and identify the conditions for effective suction methods.

METHODS

The spreading area was evaluated via image analysis of the droplets/aerosols generated by a dental air turbine on a mannequin using a light emitting diode (LED) light source and high-speed camera. The effects of different bur types and treatment sites, reduction effect of intra-oral suction (IOS) and extra-oral suction (EOS) devices, and effect of EOS installation conditions were evaluated.

RESULTS

Regarding the bur types, a bud-shaped bur on the air turbine generated the most droplets/aerosols compared with round-shaped, round end-tapered, or needle-tapered burs. Regarding the treatment site, the area of droplets/aerosols produced by an air turbine from the palatal plane of the anterior maxillary teeth was significantly higher. The generated droplet/aerosol area was reduced by 92.1% by using IOS alone and 97.8% by combining IOS and EOS. EOS most effectively aspirated droplets/aerosols when placed close (10 cm) to the mouth in the vertical direction (0°).

CONCLUSIONS

The droplets/aerosols generated by an air turbine could be visualized using an LED light and a high-speed camera in simulating dental treatments. The bur shape and position of the dental air turbine considerably influenced droplet/aerosol diffusion. The combined use of IOS and EOS at a proper position (close and perpendicular to the mouth) facilitated effective diffusion prevention to protect the dental-care environment.

Dental service utilization and the COVID-19 pandemic, a micro-data analysis

BACKGROUND

Global crises and disease pandemics, such as COVID-19, negatively affect dental care utilization by several factors, such as infection anxiety, disrupted supply chains, economic contraction, and household income reduction. Exploring the pattern of this effect can help policy makers to be prepared for future crises. The present study aimed to investigate the financial impact of COVID-19 disruptions on dental service utilization.

METHODS

Data on the number of dental services offered in Dental School Clinics of Tehran University of Medical Sciences was collected over a period of two years, before and after the initial COVID-19 outbreak in Iran. School of Dentistry operates two clinics; one with competitive service fees and one with subsidies. Regression analyses were performed to determine the effect of the pandemic on the number of dental services divided by dental treatment groups and these clinics. The analyses were adjusted for seasonal patterns and the capacity of the clinics.

RESULTS

There was a significant drop in dental services offered in both clinics across all dental groups in the post-COVID period (on average, 77 (39.44%) fewer services per day). The majority of the procedure loss happened in the Private clinic. Adjusting for seasonal patterns and the service capacity, regression results documented 54% and 12% service loss in Private and Subsidized clinics following the pandemic, respectively. Difference-in-difference analysis documented that the Subsidized clinic performed 40% more treatments than the Private clinic in the post-COVID period.

CONCLUSIONS

Pandemic -reduction in dental care utilization could have long-term ramifications for the oral health of the population, and policymakers need to provide supportive packages to the affected segments of the economy to reverse this trend.

COVID-19 in Dental Practice Is Prevented by Eugenol Responsible for the Ambient Odor Specific to Dental Offices: Possibility and Speculation

Dental professionals routinely work in proximity to patients even when either or both of them have suspected or confirmed COVID-19. The oral cavity also serves as a reservoir for SARS-CoV-2 because the virus is present in and replicates in oral secretions (saliva and gingival crevicular fluid), oral tissues (salivary gland and periodontal tissue), and oral microenvironments (gingival sulcus and periodontal pocket). Despite a high risk of SARS-CoV-2 infection, the prevalence of COVID-19 in dentists, dental hygienists, dental assistants, and their patients was similar to that in the general population even during the pandemic. We propose that eugenol, which is responsible for the ambient odor specific to dental offices, could contribute to prevention of COVID-19 in dental settings. Eugenol is not only released from dental materials (filling, cement, and sealer) but is also aerosolized by dental procedures (grinding, polishing, and restoration). Such eugenol has been suggested to possess the potential to inhibit the infectivity and replication of SARS-CoV-2, the entry of SARS-CoV-2 into human cells by binding specifically to the viral spike protein, and the protease indispensable for SARS-CoV-2 replication. It has been shown that aerosolized eugenol acts on airborne viruses to reduce their loads. This review highlights a hypothesis that the environment of dental offices impregnated with eugenol suppresses SARS-CoV-2 airborne transmission and SARS-CoV-2 contagion between dental professionals and patients, preventing COVID-19 in dental practice. Anti-COVID-19 eugenol might give insights into the safe delivery of dental treatment and oral care in the COVID-19 era.

Splatter generated by oral surgery irrigation and its implication for infection control

OBJECTIVES

This study aimed to evaluate the splatter contamination generated by rotary instrumentation and irrigation during simulations of surgical extractions. Specifically, comparisons of the splatters generated were made between traditional assistant-based irrigation and self-irrigating drills and between saline and hydrogen peroxide irrigant.

MATERIALS AND METHODS

A fluorescein solution was infiltrated into the irrigation system of high-speed drills, and the surgical extraction procedures were performed on manikins with the typodont teeth. Filter papers were placed at the predetermined locations around the operatory to absorb the fluorescein splatters; these samples underwent photographic image analysis.

RESULTS

The patient chest showed the largest area of splatters, followed by the assistant's face shield. Procedures using the hydrogen peroxide irrigant generated a larger area of splatter than those using the saline irrigant. There was no difference between the splatters produced by assistant irrigation and self-irrigating drill procedures.

CONCLUSIONS

Clinicians should observe and disinfect the locations contaminated by splatters to prevent the spread of infection, since using alternative irrigant or irrigation methods did not reduce the formation of splatters.

CLINICAL RELEVANCE

Oral surgery drills with irrigation generate aerosols and splatters, which have potential to spread airborne pathogens. It is important to understand the patterns of splatters to mitigate contamination.

Prevalence of SARS-CoV-2 infection among oral health care workers worldwide: A meta-analysis

OBJECTIVES

This systematic review aimed to answer the following question 'What are the worldwide prevalence of SARS-CoV-2 infection and associated factors among oral health-care workers (OHCWs) before vaccination?'

METHODS

Seven databases and registers as well as three grey databases were searched for observational studies in the field. Paired reviewers independently screened studies, extracted data and assessed the methodological quality. Overall seroprevalence for SARS-CoV-2 infection was analysed using a random-effect model subgrouped by professional category. Meta-regression was used to explore whether the Human Development Index (HDI) influenced the heterogeneity of results. The associated factors were narratively evaluated, and the certainty of the evidence was assessed using the GRADE approach.

RESULTS

Seventeen studies were included (five cohorts and twelve cross-sectional studies), summing 73 935 participants (54 585 dentists and 19 350 dental assistants/technicians) from 14 countries. The overall estimated pooled prevalence of SARS-CoV-2 infection among OHCWs was 9.3% (95% CI, 5.0%-14.7%; I2  = 100%, p < .01), being 9.5% for dentists (95% CI, 5.1%-15.0%; I2  = 100%, p < .01) and 11.6% for dental assistants/technicians (95% CI, 1.6%-27.4%; I2  = 99.0%, p < .01). In the meta-regression, countries with lower HDI showed higher prevalence of SARS-CoV-2 infection (p = .002). Age, comorbidities, gender, ethnicity, occupation, smoking, living in areas of greater deprivation, job role and location/municipalities, income and protective measures in dental settings were associated with positive serological SARS-CoV-2 test, with very low certainty of evidence.

CONCLUSIONS

The SARS-CoV-2 virus infected 9.3% of the OHCWs evaluated worldwide before vaccination. OHCWs should be included in policy considerations, continued research, monitoring and surveillance (PROSPERO CRD42021246520).

Impact of COVID-19 pandemic on completed treatments and referrals during urgent dental visits

This ecological study assessed the impact of the COVID-19 pandemic on completed treatments (CTs) and referrals during urgent dental visits to primary health care units in Brazil, and their associations with socioeconomic, geodemographic, and pandemic index factors in Brazilian municipalities. The difference in rates of procedures 12 months before and during the pandemic was calculated. Data were extracted at baseline from health information systems of all municipalities that provided urgent dental care (n = 5,229 out of 5,570). Multiple logistic regression predicted the factors associated with referrals and CTs. The number of dental urgencies increased from 3,987.9 to 4,272.4 per 100,000 inhabitants. The rates of referrals decreased in 44.1% of the municipalities, while 53.9% had lower rates of CTs. Municipalities with a greater number of oral health teams in the primary health care system (OR = 1.52, 95%CI:1.21-1.91) and with specialized services (OR = 1.80, 95%CI:1.50-2.16) were more likely to decrease referrals during the pandemic. Higher HDI and GDP per capita were associated with a larger decrease in referrals and smaller decrease in CTs. The calamity generated by the long pandemic period resulted in a greater demand for urgent visits. Less developed and larger cities seem to have been more likely to not complete treatments during urgent visits in primary dental care units in times of calamity. Primary dental care offices in smaller and less developed municipalities should be better equipped to provide appropriate assistance and to improve the problem-solving capacity of dental services during emergencies.

Reduction of aerosol dissemination in a dental area generated by high-speed and scaler ultrasonic devices employing the "Prime Protector"

The use of an external dome aerosol containment device (Prime Protector) is proposed to reduce the spread of particles within the dental office. Hence, the aim of our study was to compare the spread of bioaerosols generated by a High-speed Handpiece (HH) and an Ultrasonic Prophylaxis Device (UPD), with and without the Prime Protector dome (PP) by counting Colony Forming Units (CFU) of Lactobacillus casei Shirota, at different distances on the x and y axis. The PP was located considering the parallelism between the base of the dome and the frontal plane of the simulator, aligning the center of the mouth with the center of the dome. The PP dome measurements are 560.0mm x 255.0mm x 5mm. Petri dishes were placed at 0.5 m, 1 m and 1.5 m respectively. Aerosol generation in the laboratory environment was done three times with the following experimental groups 1) HH, 2) HH-PP, 3) UPD, 4) UPD-PP. Each dental device activation (HH and UPD) had a time frame of 2 minutes on the upper anterior teeth of the dental phantom with a liquid suspension containing Lactobacillus casei Shirota (YAKULT 0836A 0123; 1027F 0407). Air pressure and ventilation were parameterized. No separate high-volume evacuation used, nor was there any air removal attached to the dome. Results showed no significant difference between distance and axis in the CFU count. When means for devices and distances were compared between each of them all showed significant differences except for UPD and UPD-PP (p <0,004). In conclusion, external devices like Prime Protector could help decrease aerosol diffusion during high-speed handpiece activation. However, this dome does not replace the use of PPE inside dental clinics.

Aerosol in the oral health-care setting: a misty topic

Studies have shown that mouth and respiratory tract microorganisms can be transported in aerosol and spatter. Due to aerosol-generating procedures, there are potentially various infection risks for patients and those working in health care, especially in oral health care. Dental aerosol can contaminate not only the mucous membranes of the oral health-care professional's mouth, respiratory passages, and eyes but also exposed surfaces and materials in the environment. As such, preventing disease transmission within oral health-care offices is important issue. Since the start of the COVID-19 pandemic, an innumerable amount of (mis)information and advice on how to stay safe and prevent the spread of coronavirus has been published. What preventive measures can and have been taken to counteract this, and what have we learned during the pandemic? This review summarizes relevant literature that has addressed the presence and dispersal of aerosol and spatter as a concern in health care. It includes the sources of dental aerosol, their potential health threats, and strategies for controlling and mitigating their impact. It shows that further research is needed to better understand the potential health risks of dental aerosol and to develop effective strategies for mitigating them. CLINICAL RELEVANCE: Using personal protective equipment, high-volume evacuation systems and pre-procedural antimicrobial agents can help to reduce the potential for infection in oral health-care settings and protect the well-being of oral health-care workers and their patients.

Dental calculus - An emerging bio resource for past SARS CoV2 detection, studying its evolution and relationship with oral microflora

The most grievous threat to human health has been witnessed worldwide with the recent outbreak of Corona virus disease 2019 (COVID-19). There is mounting evidence available regarding theconnect of COVID -19 and oral cavity, particularly periodontal disease. The current review provides an update on the diagnostic potential of dental calculus and how this bio resource may help in providing us huge amount of diagnostic regarding the causative virus. Contemporary standard method of diagnosis via nasopharyngeal swabs (NPS) is tedious, may enhance the risk of aerosol contamination by inducing sneezing and detects the presence of active infection only.However,dental calculus being a mineralized deposit serves as a reservoir for biomoleculesand provides detection of past SARS CoV2 infection. Further, the abundance of information that can be obtained from this remarkable mineralized deposit on teeth regarding the viral genome, its evolution and interactions with the oral microflora shall enhance the understanding of the viral disease process and its connection with the periodontal disease. Additional diagnostic information, which may be obtained from this simple bio reservoir can complement the contemporary diagnostic strategies adopted in the management of COVID-19pandemic and enhance our existing knowledge for developing improvised novel approaches to mitigate the effects of mutated variants of the infectious agent.

Quantifying strategies to minimize aerosol dispersion in dental clinics

Many dental procedures are aerosol-generating and pose a risk for the spread of airborne diseases, including COVID-19. Several aerosol mitigation strategies are available to reduce aerosol dispersion in dental clinics, such as increasing room ventilation and using extra-oral suction devices and high-efficiency particulate air (HEPA) filtration units. However, many questions remain unanswered, including what the optimal device flow rate is and how long after a patient exits the room it is safe to start treatment of the next patient. This study used computational fluid dynamics (CFD) to quantify the effectiveness of room ventilation, an HEPA filtration unit, and two extra-oral suction devices to reduce aerosols in a dental clinic. Aerosol concentration was quantified as the particulate matter under 10 µm (PM10) using the particle size distribution generated during dental drilling. The simulations considered a 15 min procedure followed by a 30 min resting period. The efficiency of aerosol mitigation strategies was quantified by the scrubbing time, defined as the amount of time required to remove 95% of the aerosol released during the dental procedure. When no aerosol mitigation strategy was applied, PM10 reached 30 µg/m3 after 15 min of dental drilling, and then declined gradually to 0.2 µg/m3 at the end of the resting period. The scrubbing time decreased from 20 to 5 min when the room ventilation increased from 6.3 to 18 air changes per hour (ACH), and decreased from 10 to 1 min when the flow rate of the HEPA filtration unit increased from 8 to 20 ACH. The CFD simulations also predicted that the extra-oral suction devices would capture 100% of the particles emanating from the patient's mouth for device flow rates above 400 L/min. In summary, this study demonstrates that aerosol mitigation strategies can effectively reduce aerosol concentrations in dental clinics, which is expected to reduce the risk of spreading COVID-19 and other airborne diseases.

COVID-19 infection rates and mitigation strategies in orthodontic practices

BACKGROUND

COVID-19 has impacted and increased risks for all populations, including orthodontic patients and providers. It also changes the practice management and infection control landscape in the practices. This study aimed to investigate the COVID-19 infection and vaccination status of orthodontic providers and mitigation approaches in orthodontic practices in the United States during 2021.

METHODS

A validated 50-question research electronic data capture (REDCap) browser-based questionnaire was distributed to 12,393 orthodontists and pediatric dentists who reported actively providing orthodontic treatment. Questions were designed to collect demographic data of respondents, evaluate the COVID-19 mitigation approaches, and evaluate the history of COVID-19 infection and vaccination status of the orthodontic providers. Associations of demographic and the COVID-19 mitigation approaches were assessed using chi-square tests at the significance level of 0.05.

RESULTS

Four hundred fifty-seven returned the survey (response rate 3.69%) for analysis. Most respondents were vaccinated, and increased infection control measures in response to the pandemic. Half of the respondents practiced teledentistry and switched to digital impression systems. Two-thirds reported difficulties in attaining PPEs due to the increased cost and scarcity of PPEs. About 6% of respondents reported a history of COVID-19 infection, and 68.9% of their staff had COVID-19 infection. Statistically significant associations were found between increased practice experience with difficulties in acquiring PPE (p = .010). There were no significant associations between races of respondents, geographic location, and years of practicing when cross-tabulated with vaccination status or COVID-19 infection rate (p > .05).

CONCLUSION

Increased infection control strategies were employed in almost all orthodontic practices in addition to existing universal precaution. Most of the orthodontic providers and their staff members were vaccinated. While staff's infection rates were an issue, doctors' infection rates remained low.

Mouth rinses efficacy on salivary SARS-CoV-2 viral load: A randomized clinical trial

Considering the global trend to confine the COVID-19 pandemic by applying various preventive health measures, preprocedural mouth rinsing has been proposed to mitigate the transmission risk of SARS-CoV-2 in dental clinics. The study aimed to investigate the effect of different mouth rinses on salivary viral load in COVID-19 patients. This study was a single-center, randomized, double-blind, six-parallel-group, placebo-controlled clinical trial that investigated the effect of four mouth rinses (1% povidone-iodine, 1.5% hydrogen peroxide, 0.075% cetylpyridinium chloride, and 80 ppm hypochlorous acid) on salivary SARS-CoV-2 viral load relative to the distilled water and no-rinse control groups. The viral load was measured by quantitative reverse transcription PCR (RT-qPCR) at baseline and 5, 30, and 60 min post rinsing. The viral load pattern within each mouth rinse group showed a reduction overtime; however, this reduction was only statistically significant in the hydrogen peroxide group. Further, a significant reduction in the viral load was observed between povidone-iodine, hydrogen peroxide, and cetylpyridinium chloride compared to the no-rinse group at 60 min, indicating their late antiviral potential. Interestingly, a similar statistically significant reduction was also observed in the distilled water control group compared to the no-rinse group at 60 min, proposing mechanical washing of the viral particles through the rinsing procedure. Therefore, results suggest using preprocedural mouth rinses, particularly hydrogen peroxide, as a risk-mitigation step before dental procedures, along with strict adherence to other infection control measures.

The Oral Cavity Potentially Serving as a Reservoir for SARS-CoV-2 but Not Necessarily Facilitating the Spread of COVID-19 in Dental Practice

Intraoral tissues, secretions, and microenvironments may provide severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with the conditions necessary for viral cellular entry and inhabitation. The aim of the present study is to overview the oral cavity that potentially serves as a reservoir for SARS-CoV-2, and then discuss the possibility that such oral cavity facilitates the spread of coronavirus disease 2019 (COVID-19) in dental practice. Articles were retrieved from PubMed/Medline, LitCovid, ProQuest, Google Scholar, and preprint medRxiv databases. Results of the literature search indicated that SARS-CoV-2 host cell entry-relevant receptor and virus/cell membrane fusion mediators are expressed in major and minor salivary glands, tongue, taste bud, periodontal tissue, and dental pulp, which would be a target and reservoir for SARS-CoV-2. SARS-CoV-2 is present in saliva and gingival crevicular fluid of COVID-19 patients. These secretions would contaminate dental aerosol and droplet with SARS-CoV-2. SARS-CoV-2 inhabits periodontal pocket, gingival sulcus, and dental caries lesion, which could provide SARS-CoV-2 with a habitat. SARS-CoV-2 ribonucleic acid is preserved in dental calculus, which may inform of the previous infection with SARS-CoV-2. Despite involvement of the oral cavity in SARS-CoV-2 transmission and infection, to date, there have been no clusters of COVID-19 in dental practice. Dental settings are much less likely to facilitate the spread of COVID-19 compared with general medical settings, which may be explained by the situation of dentistry that the number of patients to visit dental offices/clinics was decreased during the COVID-19 pandemic, the characteristics of dentistry that dental professionals have maintained high awareness of viral infection prevention, adhered to a strict protocol for infection control, and been using personal protective equipment for a long time, the experimental results that dental devices generate only small amounts of aerosol responsible for the airborne viral transmission, irrigant from the dental unit contributes to the aerosol microbiota much rather than saliva, and the commonly used evacuation or suction system effectively reduces aerosol and droplet generation, and the possibility that human saliva exhibits the antiviral activity and the property to inhibit SARS-CoV-2 infection. It is considered that dental treatment and oral health care can be delivered safely in the COVID-19 era.

Comparison of aerosol mitigation strategies and aerosol persistence in dental environments

OBJECTIVE

To determine the impact of various aerosol mitigation interventions and to establish duration of aerosol persistence in a variety of dental clinic configurations.

METHODS

We performed aerosol measurement studies in endodontic, orthodontic, periodontic, pediatric, and general dentistry clinics. We used an optical aerosol spectrometer and wearable particulate matter sensors to measure real-time aerosol concentration from the vantage point of the dentist during routine care in a variety of clinic configurations (eg, open bay, single room, partitioned operatories). We compared the impact of aerosol mitigation strategies (eg, ventilation and high-volume evacuation (HVE), and prevalence of particulate matter) in the dental clinic environment before, during, and after high-speed drilling, slow-speed drilling, and ultrasonic scaling procedures.

RESULTS

Conical and ISOVAC HVE were superior to standard-tip evacuation for aerosol-generating procedures. When aerosols were detected in the environment, they were rapidly dispersed within minutes of completing the aerosol-generating procedure. Few aerosols were detected in dental clinics, regardless of configuration, when conical and ISOVAC HVE were used.

CONCLUSIONS

Dentists should consider using conical or ISOVAC HVE rather than standard-tip evacuators to reduce aerosols generated during routine clinical practice. Furthermore, when such effective aerosol mitigation strategies are employed, dentists need not leave dental chairs fallow between patients because aerosols are rapidly dispersed.

SARS-CoV-2 TEST OUTCOMES AMONG DENTISTS AND DENTAL HYGIENISTS WITH COVID-19-LIKE COMPLAINTS - A RETROSPECTIVE ANALYSIS FROM THE NETHERLANDS

OBJECTIVE

This retrospective analysis aimed to evaluate, among individuals with COVID-19-like symptoms, the percentage of SARS-CoV-2 positive oral health care workers relative to health care workers in general and a non-close-contact occupation reference group in the Netherlands.

MATERIALS AND METHODS

Data was retrospectively analyzed based on data extracted from the CoronIT database. This contained mass testing data for those experiencing symptoms compatible with COVID-19 recorded from June 2020 up to February 2021. The total number of tests taken and the number of SARS-CoV-2 positive tests were assessed. Sub-analyses were performed for oral health care and health care workers based in professional working locations, long-term care facilities, hospitals, or elsewhere.

RESULTS

In total, data from 1,999,390 tests were obtained. Overall, 9.4% tested positive for SARS-CoV-2 in the three occupational groups. This was 9.2% for oral health care workers, 9.5% for health care workers, and 9.3% for the non-close-contact occupation reference group. For the three occupational groups the adjusted odds ratio with the month as covariate varied from 0.76 to 1.12. The odds ratio for oral health care workers compared to health care workers was 1 [95% CI:0.95;1.05] and 0.97 [95% CI:0.92;1.02] compared to the non-close-contact occupation reference group. Interpretation of the magnitude of the odds ratio indicates that the observed differences are none to very small.

CONCLUSION

During the pandemic oral health care providers were required to adhere to the COVID-19-specific amendments to the national infection control guidelines. Based on the data gathered, dentists and dental hygienists with COVID-19-like symptoms do not test SARS-CoV-2 positive more often than other health care workers or those with a non-close-contact occupation. This supports the assumption that working during the pandemic using the Dutch standard hygiene guideline supplemented with the COVID guideline for oral health care is adequately safe.

Attitudes of COVID-19 vaccination among college students: A systematic review and meta-analysis of willingness, associated determinants, and reasons for hesitancy

The significance of COVID-19 vaccine has been declared and this study synthesizes the attitudes and determinants in vaccination hesitancy of college students. We searched in PubMed, Web of Science, Cochrane Library and CNKI to enroll the related studies. The modified NOS was used for quality evaluation. Proportion and OR with 95% CI were pooled to estimate the acceptance rates and determinants of COVID-19 vaccination. Data of 34 studies involving 42 countries were pooled. The pooled acceptance rate of COVID-19 vaccination among all the college students was 69% and varies between countries, while medical students have a slightly higher acceptancy rate. Knowledge, trust conception, social behavior, and information sources were important for their decision. Most of the college students intended to COVID-19 vaccination, but the proportion varied among countries. Governments should strengthen credibility, convey trusted information with media influences and improve vaccination services in urging students to be vaccinated.

Aerosol concentrations and size distributions during clinical dental procedures

Background

Suspected aerosol-generating dental instruments may cause risks for operators by transmitting pathogens, such as the SARS-CoV-2 virus. The aim of our study was to measure aerosol generation in various dental procedures in clinical settings.

Methods

The study population comprised of 84 patients who underwent 253 different dental procedures measured with Optical Particle Sizer in a dental office setting. Aerosol particles from 0.3 to 10 μm in diameter were measured. Dental procedures included oral examinations (N = 52), restorative procedures with air turbine handpiece (N = 8), high-speed (N = 6) and low-speed (N = 30) handpieces, ultrasonic scaling (N = 31), periodontal treatment using hand instruments (N = 60), endodontic treatment (N = 12), intraoral radiographs (N = 24), and dental local anesthesia (N = 31).

Results

Air turbine handpieces significantly elevated <1 μm particle median (p = 0.013) and maximum (p = 0.016) aerosol number concentrations as well as aerosol particle mass concentrations (p = 0.046 and p = 0.006) compared to the background aerosol levels preceding the operation. Low-speed dental handpieces elevated >5 μm median (p = 0.023), maximum (p = 0.013) particle number concentrations,> 5 μm particle mass concentrations (p = 0.021) and maximum total particle mass concentrations (p = 0.022). High-speed dental handpieces elevated aerosol concentration levels compared to the levels produced during oral examination.

Conclusions

Air turbine handpieces produced the highest levels of <1 μm aerosols and total particle number concentrations when compared to the other commonly used instruments. In addition, high- and low-speed dental handpieces and ultrasonic scalers elevated the aerosol concentration levels compared to the aerosol levels measured during oral examination. These aerosol-generating procedures, involving air turbine, high- and low-speed handpiece, and ultrasonic scaler, should be performed with caution.

Clinical significance

Aerosol generating dental instruments, especially air turbine, should be used with adequate precautions (rubber dam, high-volume evacuation, FFP-respirators), because aerosols can cause a potential risk for operators and substitution of air turbine for high-speed dental handpiece in poor epidemic situations should be considered to reduce the risk of aerosol transmission.

Coronavirus outbreaks and infection prevention in dentistry: a narrative review

OBJECTIVE

This narrative review aims to compile and analyse infection prevention and control (IPAC) practices followed by dental clinics during 3 coronavirus outbreaks: SARS (2002-2004), MERS (2012-2014), and COVID-19 (2019-); and to draw parallels from them for future epidemics.

METHODS

Data were collected from 3 databases: Google Scholar, PubMed, and Embase using search terms "SARS," "MERS," "COVID-19," "infection control," "disinfection," and "sterilization".

RESULTS

Careful examination of 108 peer-reviewed articles on the 3 outbreaks revealed the following commonalities in the IPAC practices of dental clinics: use of sodium hypochlorite (surface disinfectant), ethanol and 1-propanol (hand hygiene), povidone-iodine (oral rinse), high-volume evacuation (HVE), rubber dam isolation, anti-retraction handpieces, and fogging.

DISCUSSION & CONCLUSION

Ethanol, 1-propanol, sodium hypochlorite, povidone-iodine, photocatalysis, and fogging have been shown to be effective against various coronaviruses. However, more studies are required to validate the effectiveness of anti-retraction handpieces, rubber dam isolation, HVE, and cold atmospheric plasma specifically in infection control of the current coronavirus strain, SARS-CoV-2.

Oral Lesions Associated with COVID-19 and the Participation of the Buccal Cavity as a Key Player for Establishment of Immunity against SARS-CoV-2

BACKGROUND

Some oral lesions have been described in patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2); the possibility has been raised that the buccal lesions observed in patients with the coronavirus disease 2019 (COVID-19) are due to this virus and the patient's systemic condition. The aim of this review was to integrate the knowledge related to the oral lesions associated with COVID-19 and the participation of the buccal cavity in the establishment of immunity against SARS-CoV-2.

METHODS

A literature search on the manifestations of buccal lesions from the beginning of the pandemic until October 2021 was carried out by using the PubMed database. A total of 157 scientific articles were selected from the library, which included case reports and reports of lesions appearing in patients with COVID-19.

RESULTS

Oral lesions included erosions, ulcers, vesicles, pustules, plaques, depapillated tongue, and pigmentations, among others. The oral cavity is a conducive environment for the interaction of SARS-CoV-2 with the mucosal immune system and target cells; direct effects of the virus in this cavity worsen the antiviral inflammatory response of underlying oral disorders, immunodeficiencies, and autoimmunity primarily.

CONCLUSIONS

The oral cavity is an accessible and privileged environment for the interaction of SARS-CoV-2 with the mucosal immune system and target cells; the direct effects of the virus in this cavity worsen the antiviral inflammatory response of underlying oral disorders, in particular those related to immunodeficiencies and autoimmunity.

Dental Care and Education Facing Highly Transmissible SARS-CoV-2 Variants: Prospective Biosafety Setting: Prospective, Single-Arm, Single-Center Study

With the arrival of the highly transmissible Omicron variants (BA.4 and BA.5), dentistry faces another seasonal challenge to preserve the biosafety of dental care and education. With the aim of protecting patients, students, teachers and healthcare professionals, this paper introduces a prospective sustainable biosafety setting for everyday dental care and education. The setting developed by dental clinicians, epidemiologists, and teachers of dentistry consists of a combination of modern technologies focused on the air-borne part of the viral pathway. The introduced biosafety setting has been clinically evaluated after 18 months of application in the real clinical environment. The protocol has three fundamental pillars: (1) UVC air disinfection; (2) air saturation with certified virucidal essences with nebulizing diffusers; (3) complementary solutions including telehealth and 3D printing. A pseudonymous online smart form was used as the evaluation method. The protocol operates on the premise that everybody is a hypothetical asymptomatic carrier. The results of a clinical evaluation of 115 patient feedbacks imply that no virus transmission from patient to patient or from doctor to nurse was observed or reported using this protocol, and vice versa, although nine patients retrospectively admitted that the clinic visit is likely to be infectious. Despite these promising results, a larger clinical sample and exposition to the current mutated strains are needed for reliable conclusions about protocol virucidal efficiency in current dental environments.

Positivity rates of SAR-CoV-2 infection in orthodontic patients at the orthodontic clinic, University of Illinois Chicago

COVID-19 has impacted and increased risks for healthcare providers, including orthodontists. There is no information regarding the potential transmission risks in the orthodontic community. This study aims to compare the positivity rate of SARS-CoV-2 infection in orthodontic patients at the University of Illinois Chicago (UIC) orthodontic clinic to the positivity rate of the local population in Chicago. All orthodontic patients who sought treatment at the UIC orthodontic clinic from June 16 to October 31, 2021, were invited to participate in the study. Three milliliters of saliva from the participants were collected in the sample collection tubes and subjected to a polymerase chain reaction (PCR) based assay to detect SAR-CoV-2. All participants’ age, sex, history of COVID-19 infection, and vaccination status were recorded. The COVID-19 positivity rates of Chicago, Cook County of Illinois, and the orthodontic clinic at UIC were compared. One thousand four hundred and thirty-seven orthodontic patients aged 6 to 70 years old (41.8% males and 58.2% females) participated in the study. Among all participants, nine participants tested positive for SARS-CoV-2 (5 males and 4 females). During the study, the average COVID-19 positivity rate at the UIC orthodontic clinic was 0.626%. All of the positive participants were asymptomatic, and two of the participants had a history of COVID-19 infection. Among all positive participants, three participants had received complete COVID-19 vaccination. An increased frequency of positive cases at the orthodontic clinic was observed during the time of high positivity rate in Chicago and Cook County. A potential risk of COVID-19 transmission from patients to orthodontic providers remains, even with asymptomatic and vaccinated patients.

Simulated and clinical aerosol spread in common periodontal aerosol-generating procedures

Objectives

This study evaluated particle spread associated with various common periodontal aerosol-generating procedures (AGPs) in simulated and clinical settings.

Materials and methods

A simulation study visualized the aerosols, droplets, and splatter spread with and without high-volume suction (HVS, 325 L/min) during common dental AGPs, namely ultrasonic scaling, air flow prophylaxis, and implant drilling after fluorescein dye was added to the water irrigant as a tracer. Each procedure was repeated 10 times. A complementary clinical study measured the spread of contaminated particles within the dental operatory and quantified airborne protein dispersion following 10 min of ultrasonic supragingival scaling of 19 participants during routine periodontal treatment.

Results

The simulation study data showed that air flow produced the highest amount of splatters and the ultrasonic scaler generated the most aerosol and droplet particles at 1.2 m away from the source. The use of HVS effectively reduced 37.5–96% of splatter generation for all three dental AGPs, as well as 82–93% of aerosol and droplet particles at 1.2 m for the ultrasonic scaler and air polisher. In the clinical study, higher protein levels above background levels following ultrasonic supragingival scaling were detected in fewer than 20% of patients, indicating minimal particle spread.

Conclusions

While three common periodontal AGPs produce aerosols and droplet particles up to at least 1.2 m from the source, the use of HVS is of significant benefit. Routine ultrasonic supragingival scaling produced few detectable traces of salivary protein at various sites throughout the 10-min dental operatory.

Clinical relevance

The likelihood of aerosol spread to distant sites during common periodontal AGPs is greatly reduced by high-volume suction. Clinically, limited evidence of protein contaminants was found following routine ultrasonic scaling, suggesting that the the majority of the contamination consisits of the irrigant rather than organic matter from the oral cavity.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00784-022-04532-8.

Assessment of a Biosafety Device to Control Contamination by Airborne Transmission during Orthodontic/Dental Procedures

During the COVID-19 pandemic, dental professionals have faced high risk of airborne contamination between dentists, staff, and patients. The objective of this study was to evaluate the effect of an individual biosafety capsule in dentistry (IBCD) on reducing the dispersion of droplets and aerosols during orthodontic treatment and evaluate the clinician and patient’s perception of using the IBCD. For the in-vitro part of the study, aerosol quantification was performed with and without the IBCD, using a nonpathogenic bacterial strain and viral strain in the reservoir and high-speed dental handpiece. Petri dishes with MRS agar were positioned from the head of the equipment at distances of 0.5, 1, and 1.5 m. After 15 minutes of passive aerosol sampling, the dishes were closed and incubated using standard aerobic conditions at 37°C for 48 hours to count colony forming units (CFUs). For the clinical part of the study, a questionnaire was sent to clinicians and patients to understand their perception of orthodontically treat and receive treatment using the barrier. The use of IBCD showed an effective means to reduce the dispersion of bacterial and viral contamination around 99% and 96%, respectively, around the main source of aerosol ( $p<0.05$ ). Clinical results showed a 97% bacterial reduction during patient’s consultations ( $p<0.05$ ). The vast majority of clinicians and patients understand the importance of controlling the airborne dispersion to avoid contamination.

Particle Size, Mass Concentration, and Microbiota in Dental Aerosols

Many dental procedures are considered aerosol-generating procedures that may put the dental operator and patients at risk for cross-infection due to contamination from nasal secretions and saliva. This aerosol, depending on the size of the particles, may stay suspended in the air for hours. The primary objective of the study was to characterize the size and concentrations of particles emitted from 7 different dental procedures, as well as estimate the contribution of the nasal and salivary fluids of the patient to the microbiota in the emitted bioaerosol. This cross-sectional study was conducted in an open-concept dental clinic with multiple operators at the same time. Particle size characterization and mass and particle concentrations were done by using 2 direct reading instruments: Dust-Trak DRX (Model 8534) and optical particle sizer (Model 3330). Active bioaerosol sampling was done before and during procedures. Bayesian modeling (SourceTracker2) of long-reads of the 16S ribosomal DNA was used to estimate the contribution of the patients’ nasal and salivary fluids to the bioaerosol. Aerosols in most dental procedures were sub-PM₁ dominant. Orthodontic debonding and denture adjustment consistently demonstrated more particles in the PM₁, PM_2.5, PM₄, and PM₁₀ ranges. The microbiota in bioaerosol samples were significantly different from saliva and nasal samples in both membership and abundance (P < 0.05) but not different from preoperative ambient air samples. A median of 80.15% of operator exposure was attributable to sources other than the patients’ salivary or nasal fluids. Median operator’s exposure from patients’ fluids ranged from 1.45% to 2.75%. Corridor microbiota showed more patients’ nasal bioaerosols than oral bioaerosols. High-volume saliva ejector and saliva ejector were effective in reducing bioaerosol escape. Patient nasal and salivary fluids are minor contributors to the operator’s bioaerosol exposure, which has important implications for COVID-19. Control of bioaerosolization of nasal fluids warrants further investigation.

The Impact of COVID-19 on the Oral Health of Patients with Special Needs

In March 2020, the World Health Organization declared a global public health emergency due to the spread of COVID-19, and medical and dental elective care was suspended, disproportionally affecting persons with special needs. As many of the special needs population live in a communal environment, they were at higher risk of being infected with and dying of COVID-19. Consequently, their access to medical and dental services was limited to emergency care. A method of reaching these populations evolved by the expansion of telehealth, including dentistry, to provide diagnosis, management, prevention, and provision of psychosocial support for patients.

A clinical observational analysis of aerosol emissions from dental procedures

Aerosol generating procedures (AGPs) are defined as any procedure releasing airborne particles <5 μm in size from the respiratory tract. There remains uncertainty about which dental procedures constitute AGPs. We quantified the aerosol number concentration generated during a range of periodontal, oral surgery and orthodontic procedures using an aerodynamic particle sizer, which measures aerosol number concentrations and size distribution across the 0.5-20 μm diameter size range. Measurements were conducted in an environment with a sufficiently low background to detect a patient's cough, enabling confident identification of aerosol. Phantom head control experiments for each procedure were performed under the same conditions as a comparison. Where aerosol was detected during a patient procedure, we assessed whether the size distribution could be explained by the non-salivary contaminated instrument source in the respective phantom head control procedure using a two-sided unpaired t-test (comparing the mode widths (log(σ)) and peak positions (DP,C)). The aerosol size distribution provided a robust fingerprint of aerosol emission from a source. 41 patients underwent fifteen different dental procedures. For nine procedures, no aerosol was detected above background. Where aerosol was detected, the percentage of procedure time that aerosol was observed above background ranged from 12.7% for ultrasonic scaling, to 42.9% for 3-in-1 air + water syringe. For ultrasonic scaling, 3-in-1 syringe use and surgical drilling, the aerosol size distribution matched the non-salivary contaminated instrument source, with no unexplained aerosol. High and slow speed drilling produced aerosol from patient procedures with different size distributions to those measured from the phantom head controls (mode widths log(σ)) and peaks (DP,C, p< 0.002) and, therefore, may pose a greater risk of salivary contamination. This study provides evidence for sources of aerosol generation during common dental procedures, enabling more informed evaluation of risk and appropriate mitigation strategies.

Efficacy of Aerosol Reduction Measures for Dental Aerosol Generating Procedures

Aerosol particles generated by dental procedures could facilitate the transmission of infectious diseases and contain carcinogen particles. Such particles can penetrate common surgical masks and reach the lungs, leading to increased risk for dental care professionals. However, the risk of inhaling contaminated aerosol and the effectiveness of aerosol reduction measures in dental offices remain unclear. The present study aimed to quantify aerosols produced by drilling and scaling procedures and to evaluate present recommendations for aerosol reduction. The concentration of aerosol particles released from the mock scaling and drilling procedures on dental mannequin were measured using a TSI Optical Particle Sizer (OPS 3330) during 15-min sessions carried out in a single-patient examination room. Using a drilling procedure as the aerosol source, the aerosol reduction performance of two types of high-volume evacuators (HVEs) and a commercial off-the-shelf air purifier was evaluated in a simulated clinical setting. Using either HVEs or the air purifier individually reduced the aerosol accumulated over the course of a 15-minutes drilling procedure at a reduction rate of 94.8 to 97.6%. Using both measures simultaneously raised the reduction rate to 99.6%. The results show that existing HVEs can effectively reduce aerosol concentration generated by a drilling procedure and can be further improved by using an air purifier. Following current regulatory guidelines can ensure a low risk of inhaling contaminated aerosol for dentists, assistants, and patients.

The Impact of the COVID-19 Pandemic on Dentistry and Dental Education: A Narrative Review

Dentists and dental staff have an increased risk of airborne infection with pathogens such as SARS-CoV-2 since they are exposed to high levels of droplets and aerosols produced during specific dental procedures. Hence, new guidelines such as patient screening and temperature control, air purification, space, surface and hand sanitizing and the use of protective equipment and physical barriers have been successfully implemented. In addition, the use of teledentistry has expanded considerably in pediatric dentistry, orthodontics, oral medicine and periodontics in order to address oral and dental health issues during the COVID-19 pandemic while minimizing virus transmission. Thus, teleconsultation, telediagnosis, teletriage, teletreatment and telemonitoring have emerged as valuable tools not only in the delivery of care, but also in the academic and research training of dental health professionals. This narrative review summarizes the current literature on the impact of the pandemic on dental care, dental staff and dental education, with an emphasis on how newly emerging protocols and technologies can be successfully utilized as integral parts of various branches of the dental practice and their future implications without compromising patient care.

Prevalence of SARS-CoV-2 IgG antibodies among dental teams in Germany

Objectives

During the corona pandemic, dental practices temporarily closed their doors to patients except for emergency treatments. Due to the daily occupational exposure, the risk of SARS-CoV-2 transmission among dentists and their team is presumed to be higher than that in the general population. This study examined this issue among dental teams across Germany.

Materials and methods

In total, 2784 participants provided usable questionnaires and dry blood samples. Dry blood samples were used to detect IgG antibodies against SARS-CoV-2. The questionnaires were analyzed to investigate demographic data and working conditions during the pandemic. Multivariable logistic mixed-effects models were applied.

Results

We observed 146 participants with positive SARS-CoV-2 IgG antibodies (5.2%) and 30 subjects with a borderline finding (1.1%). Seventy-four out of the 146 participants with SARS-CoV-2 IgG antibodies did not report a positive SARS-CoV-2 PCR test (50.7%), while 27 participants without SARS-CoV-2 IgG antibodies reported a positive SARS-CoV-2 PCR test (1.1%). Combining the laboratory and self-reported information, the number of participants with a SARS-CoV-2 infection was 179 (6.5%). Though after adjustment for region, mixed-effects models indicated associations of use of rubber dams (OR 1.65; 95% CI: 1.01–2.72) and the number of protective measures (OR 1.16; 95% CI: 1.01–1.34) with increased risk for positive SARS-CoV-2 status, none of those variables was significantly associated with a SARS-CoV-2 status in fully adjusted models.

Conclusions

The risk of SARS-CoV-2 transmission was not higher among the dental team compared to the general population.

Clinical relevance.

Following hygienic regulations and infection control measures ensures the safety of the dental team and their patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00784-021-04363-z.

Knowledge and Attitude towards Orthodontic Treatment among Non-Orthodontic Specialists: An Online Survey in Croatia

Objectives: The aim of this study was to examine the knowledge and attitudes towards orthodontic treatment among non-orthodontic specialists. Methods: A web-based survey was formulated for non-orthodontic dental specialists to respond to statements regarding an orthodontic treatment. It contained 20 multiple-choice questions with three or more possible answers. Two hundred and fifty questionnaires were sent via email, with explanatory letters, to randomly selected non-orthodontic Croatian dental specialists. Data were assessed using IBAM SPSS 23.0. and p < 0.01 was considered significant. Results: The results indicate that the majority of respondents were well informed about principles and practices in orthodontics. All the respondents (100%) were aware that malocclusions can affect a patient’s facial aesthetic and masticatory function. The results also showed statistically significant differences in answers about contraindications for orthodontics therapy among different non-orthodontic specialists (p < 0.01). Private health practitioners were better informed about the ideal time for the first orthodontic appointment (74.2%) and that implants and periodontal problems are not contraindications for orthodontic treatment (over 70%), in comparison with public health practitioners. Conclusion: Non-orthodontic specialists in this sample exhibit encouraging awareness and knowledge of the principals and practices of orthodontic treatment. Additional improving of practitioners’ knowledge and awareness can help patients with malocclusion to decide upon orthodontic treatment at earlier stages and avoid later complications in the future.

Virucidal Activity of Different Mouthwashes Using a Novel Biochemical Assay

BACKGROUND

Saliva of patients with COVID-19 has a high SARS-CoV-2 viral load. The risk of spreading the virus is not insignificant, and procedures for reducing viral loads in the oral cavity have been proposed. Little research to date has been performed on the effect of mouthwashes on the SARS-CoV-2 virus, and some of their mechanisms of action remain unknown.

METHODS

SARS-CoV-2 positive nasopharyngeal swabs measured by RT-PCR were used for virucidal activity in a 1:1 ratio, with an incubation time of 1 min. The solutions used in this study were: iodopovidone (8 mg); * D-limonene, a terpene extracted from citrus peels (0.3%); † cetylpyridinium chloride (0.1%) (CPC); ‡ chlorhexidine gluconate (10%) (CHX); § a CPC (0.12%) and CHX (0.05%) containing formula; ** a formula containing essential oils; †† a CPC containing formula (0.07%); ‡‡ a D-limonene (0.2%) and CPC (0.05%) containing formula; §§ a solution containing sodium fluoride (0.05%) and CPC (0.075%); *** a solution containing CHX (0.12%) and; ††† a CHX (0.2%) containing formula. ‡‡‡ As a control reaction, saline solution or excipient solution (water, glycerin, citric acid, colorant, sodium citrate) was used.

CONCLUSION

Within the limitations of this study, we can conclude that a mouthwash containing both D-limonene and CPC reduced the virucidal activity in about 6 logs (>99.999% reduction). Hence, establishing a clinical protocol for dentists is suggested, where all patients to be treated rinse pre-operatively with a mouthwash containing both D-limonene and CPC to reduce the likelihood of infection with SARS-CoV-2 for dentists. This is a relatively inexpensive way to reduce viral transmission of SARS-CoV-2 from infected individuals within the community. It is also a simple way to decrease infections from asymptomatic and pre-symptomatic patients.

Application of recommended preventive measures against COVID-19 could help mitigate the risk of SARS-CoV-2 infection during dental practice: Results from a follow-up survey of French dentists

Background

During the first-wave of the COVID-19 pandemic, dentists were considered at high-risk of infection. In France, to stop the spread of SARS-CoV-2, a nationwide lockdown was enforced, during which dentists suspended their routine clinical activities, working solely on dental emergencies. This measure has had an indisputable mitigating effect on the pandemic. To continue protecting dentists after suspension of nationwide lockdown, implementation of preventive measures was recommended, including adequate personal protective equipment (PPE) and room aeration between patients. No study has explored whether implementation of such preventive measures since the end of the first-wave has had an impact on the contamination of dentists.

Methods

An online survey was conducted within a French dentist population between July and September 2020. To explore risk factors associated with COVID-19, univariate and multivariate logistic regression analyses were performed.

Results

The results showed that COVID-19 prevalence among the 3497 respondents was 3.6%. Wearing surgical masks during non-aerosol generating procedures was a risk factor of COVID-19, whereas reducing the number of patients was a protective factor.

Conclusions

Considering the similar COVID-19 prevalence between dentists and the general population, such data suggest that dentists are not overexposed in their work environment when adequate preventive measures are applied.

Impact

Dentists should wear specific PPE (FFP2, FFP3 or (K)N95 masks) including during non-aerosol generating procedures and reduce the number of patients to allow proper implementation of disinfection and aeration procedures. Considering the similarities between COVID-19 and other viral respiratory infections, such preventive measures may also be of interest to limit emerging variants spread as well as seasonal viral outbreaks.

Dental Mitigation Strategies to Reduce Aerosolization of SARS-CoV-2

Limiting infection transmission is central to the safety of all in dentistry, particularly during the current severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. Aerosol-generating procedures (AGPs) are crucial to the practice of dentistry; it is imperative to understand the inherent risks of viral dispersion associated with AGPs and the efficacy of available mitigation strategies. In a dental surgery setting, crown preparation and root canal access procedures were performed with an air turbine or high-speed contra-angle handpiece (HSCAH), with mitigation via rubber dam or high-volume aspiration and a no-mitigation control. A phantom head was used with a 1.5-mL min-1 flow of artificial saliva infected with Φ6-bacteriophage (a surrogate virus for SARS-CoV-2) at ~108 plaque-forming units mL-1, reflecting the upper limits of reported salivary SARS-CoV-2 levels. Bioaerosol dispersal was measured using agar settle plates lawned with the Φ6-bacteriophage host, Pseudomonas syringae. Viral air concentrations were assessed using MicroBio MB2 air sampling and particle quantities using Kanomax 3889 GEOα counters. Compared to an air turbine, the HSCAH reduced settled bioaerosols by 99.72%, 100.00%, and 100.00% for no mitigation, aspiration, and rubber dam, respectively. Bacteriophage concentrations in the air were reduced by 99.98%, 100.00%, and 100.00% with the same mitigations. Use of the HSCAH with high-volume aspiration resulted in no detectable bacteriophage, both on nonsplatter settle plates and in air samples taken 6 to 10 min postprocedure. To our knowledge, this study is the first to report the aerosolization in a dental clinic of active virus as a marker for risk determination. While this model represents a worst-case scenario for possible SARS-CoV-2 dispersal, these data showed that the use of HSCAHs can vastly reduce the risk of viral aerosolization and therefore remove the need for clinic fallow time. Furthermore, our findings indicate that the use of particle analysis alone cannot provide sufficient insight to understand bioaerosol infection risk.

Knowledge, Attitude, and Practices of Dentists in Caribbean Countries during the COVID-19 Pandemic: A Multicenter Cross-Sectional Study

Background: The COVID-19 pandemic has affected dentists globally, both financially and mentally. This study aimed to determine the knowledge, attitude, and practices of dentists in Caribbean countries during the COVID-19 pandemic. Methods: A non-probability sample was obtained from dentists in more than ten different Caribbean countries. They were invited to complete a self-reported questionnaire, which was conducted from December 2020 to March 2021. Ethics approval was sought and an exemption was received from the UWI ethics committee. Results: One hundred and fifty-two dentists responded. More than one-third (38.8%) were in the >35–45 age group, and 58.6% were females. Most (84.9%) were general dentists and 75% were stressed by the COVID-19 situation with 80.9% being affected financially. The majority, 94.7%, believed that the highest risk of transmission of COVID-19 was via aerosol-generating procedures and 87.5% were worried about contracting it clinically. The majority (69.1%) were willing to receive the vaccine, the main reason reported for vaccine hesitancy was due to the possible side effects (35.3%). Most (75%) consumed alcohol. When the locus of control was determined, 54.6% felt they were in control of protecting themselves while 52% felt that external factors controlled their lives. Conclusions: The findings suggest that most dentists in the Caribbean were knowledgeable about COVID-19 and followed current guidelines in their practice and were willing to receive the vaccine.

Local Exhaust Ventilation to Control Dental Aerosols and Droplets

Dental procedures produce aerosols that may remain suspended and travel significant distances from the source. Dental aerosols and droplets contain oral microbes, and there is potential for infectious disease transmission and major disruption to dental services during infectious disease outbreaks. One method to control hazardous aerosols often used in industry is local exhaust ventilation (LEV). The aim of this study was to investigate the effect of LEV on aerosols and droplets produced during dental procedures. Experiments were conducted on dental mannequins in an 825.4-m³ open-plan clinic and a 49.3-m³ single surgery. Ten-minute crown preparations were performed with an air-turbine handpiece in the open-plan clinic and 10-min full-mouth ultrasonic scaling in the single surgery. Fluorescein was added to instrument irrigation reservoirs as a tracer. In both settings, optical particle counters (OPCs) were used to measure aerosol particles between 0.3 and 10.0 µm, and liquid cyclone air samplers were used to capture aerosolized fluorescein tracer. In addition, in the open-plan setting, fluorescein tracer was captured by passive settling onto filter papers in the environment. Tracer was quantified fluorometrically. An LEV device with high-efficiency particulate air filtration and a flow rate of 5,000 L/min was used. LEV reduced aerosol production from the air-turbine handpiece by 90% within 0.5 m, and this was 99% for the ultrasonic scaler. OPC particle counts were substantially reduced for both procedures and air-turbine settled droplet detection reduced by 95% within 0.5 m. The effect of LEV was substantially greater than suction alone for the air-turbine and was similar to the effect of suction for the ultrasonic scaler. LEV reduces aerosol and droplet contamination from dental procedures by at least 90% in the breathing zone of the operator, and it is therefore a valuable tool to reduce the dispersion of dental aerosols.

The Spread of Droplets and Aerosols of Surgical Motor Handpiece Irrigation Using Different Suction Systems

Objective: This study aimed to compare the effectiveness of various combinations of dental suction devices in reducing the amount and distance of spread of aerosols and droplets using an electrical surgical motor model with a self-irrigation system.

Materials and Methods: In a standard single-chaired air-conditioned ventilated dental clinic, an electrical dental surgical motor with a high-speed handpiece (Implantmed) cooled with 0.2% fluorescein containing normal saline was used to drill a gypsum block mounted on a phantom head in a supine position. A single operator performed thrice each of the following suction settings: (a) no suction, (b) low-volume suction, (c) low-volume + high-volume suctions, and (d) low-volume + external oral suctions. Aerosols (0.1–5 μm) were measured with a particle counter at the mouth opening of the phantom head, and droplet sizes and distances were analyzed via a machine learning algorithm by identifying fluorescence droplets on pre-loaded pieces of paper on the floor for each group.

Results: The different suction systems have different performances in terms of droplet distance (p = 0.007), whereas using (c) high volume suctions (41.1 ± 22.9 cm) and (d) external oral suction unit (39 ± 18.2 cm) had significantly reduced the spread of droplets when compared with (a) without suction (58.9 ± 17.1 cm). Using (d) external oral suction or (c) high volume suction could reduce the number for all droplet sizes. The use of (c) high volume suction was most effective in reducing aerosol count of 0.3–1 μm, while (d) external oral suction was most effective in reducing aerosol count of 3–5 μm.

Conclusions: Both external oral suction and high-volume suction were effective in reducing aerosols and droplets generated by the irrigation of a surgical high-speed motor handpiece. External oral suction could be an effective alternative to high volume suction in dental surgical procedures to reduce the spread of aerosols and droplets.

Clinical Relevance: External oral suction or high-volume suction should be used in conjunction with low-volume suction in surgical procedure to reduce the spread of aerosols and droplets in a dental clinic environment.

How the high-volume evacuation alters the flow-field and particle removal characteristics in the mock-up dental clinic

The exposure risk of droplets and aerosols emitted from the oral cavity to the dental professionals and patients has received more attention especially the ongoing outbreak of COVID-19. The aim of this study is to address the question about how the use of the high-volume evacuation (HVE) alters the risk profiles compared with the situation only personal protective equipment (PPE). The risk profiles of the different situations were analyzed in terms of droplet velocity, flow field characteristics, and particle removal efficiency. The ultrasonic scaling with suction was performed in the mock-up experimental dental clinic, and the instantaneous moment when the HVE acted on the droplets was visualized using a laser light scattering technique. From the results of the velocity profiles, the hypothesis about the moderate effect of the HVE on high-velocity small droplets near the mannequin's mouth had been firstly proven in this study. The suction can be characterized as low-threshold equipment to bring substantial benefits to reduce the area of the contaminated region. Once the cooperation of suction, the pair of vortexes that were in the face shield area of the dental professional would be eliminated, removing the high-level contaminated region near the breathing area of dental professionals. Compared with the low and medium volume evacuation, the particle removal efficiency of the HVE was more stable at 60%. The research will provide references to the HVE recommendation in the dentistry clinical practice guidelines.

Endodontics Specialists' Practice during the Initial Outbreak of Coronavirus Disease 2019

INTRODUCTION

The first outbreak of coronavirus disease 2019 (COVID-19) in the United States resulted in a nationwide closure of dental offices that created an oral health crisis. The aim of this observational study was to analyze and compare the characteristics of patients who visited 2 private endodontics offices from March 16 to May 31, 2020, compared with the same period in 2019.

METHODS

Demographic, diagnostic, and procedural data of 1520 (693 in 2020 and 827 in 2019) patient visits were collected. Bivariate and multiple logistic regression analyses were used to assess the impact of the COVID-19 outbreak on patient-related variables.

RESULTS

Bivariate analyses showed that the number of patient visits decreased in April and May 2020 (P < .0001). In 2020, patients' self-reported pain level was higher, they were more frequently diagnosed with pulp necrosis and acute apical abscess, and they received more incisions for drainage (P < .05). Multiple logistic regression analyses showed that the COVID-19 outbreak was associated with less visits for older patients (>49.5 years) (odds ratio [OR] = 0.720; 95% confidence interval [CI], 0.573-0.906), more patients with kidney diseases (OR = 2.690; 95% CI, 1.143-6.331), higher levels of pain on percussion (OR = 2.277; 95% CI, 1.718-3.016), less cases with previously initiated treatment (OR = 0.242; 95% CI, 0.080-0.731), less periapical diagnoses of asymptomatic apical periodontitis (OR = 0.510; 95% CI, 0.306-0.849), and a higher number of nonsurgical root canal treatments (OR = 2.073; 95% CI, 1.397-3.074) and apicoectomies (OR = 2.799; 95% CI, 1.367-5.729).

CONCLUSIONS

These findings show that the public health burden of endodontic infections was more intense during the initial outbreak of COVID-19.

The "oral" history of COVID-19: Primary infection, salivary transmission, and post-acute implications

Severe acute respiratorysyndrome coronavirus 2 (SARS-CoV-2), the causative agent of COVID-19, has led to more than 3.25 million recorded deaths worldwide as of May 2021. COVID-19 is known to be clinically heterogeneous, and whether the reported oral signs and symptoms in COVID-19 are related to the direct infection of oral tissues has remained unknown. Here, we review and summarize the evidence for the primary infection of the glands, oral mucosae, and saliva by SARS-CoV-2. Not only were the entry factors for SARS-CoV-2 found in all oral tissues, but these were also sites of SARS-CoV-2 infection and replication. Furthermore, saliva from asymptomatic individuals contained free virus and SARS-CoV-2-infected oral epithelial cells, both of which were found to transmit the virus. Collectively, these studies support an active role of the oral cavity in the spread and transmission of SARS-CoV-2 infection. In addition to maintaining the appropriate use of personal protective equipment and regimens to limit microbial spread via aerosol or droplet generation, the dental community will also be involved in co-managing COVID-19 "long haulers"-now termed Post-Acute COVID-19 Syndrome. Consequently, we propose that, as SARS-CoV-2 continues to spread and as new clinical challenges related to COVID-19 are documented, oral symptoms should be included in diagnostic and prognostic classifications as well as plans for multidisciplinary care.

Occupational Infections among Dental Health Workers in Germany-14-Year Time Trends

Dental health workers (DHW) are at increased risk of acquiring occupational infections. Due to various protective measures, it can be assumed that infections have decreased over the past 14 years. Secondary data from a German accident insurance company was analyzed in terms of reported and confirmed occupational diseases (OD) in DHW from 2006 to 2019. A total of 271 claims were reported, of which 112 were confirmed as OD, representing an average of eight per year. However, the number of claims and confirmed ODs has decreased by 65.6% and 85.7%, respectively. The decrease was most evident for hepatitis B (HBV) and C (HCV) infections, while tuberculosis (TB) infections were stable. A total of 44 HCV, 33 HBV, 6 TB and 24 latent TB infections were confirmed as ODs. For DHW, 0.05, and for hospital workers, 0.48 claims per 1000 full-time equivalents (FTE) were registered in 2019. In a separate documentation system, between March 2020 and February 2021, 155 COVID-19 claims were registered, and 47 cases were confirmed as ODs. For DHW, 0.7, and for hospital workers, 47.3 COVID-19 claims per 1000 FTE were registered since 2020. Occupational infectious diseases rarely occur among DHW. Nevertheless, new infectious diseases such as COVID-19 pose a major challenge for DHW. Continued attention should be paid to infectious disease prevention.

Estimating salivary carriage of severe acute respiratory syndrome coronavirus 2 in nonsymptomatic people and efficacy of mouthrinse in reducing viral load: A randomized controlled trial

Background

Many people infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) never develop substantial symptoms. With more than 34 million people in the United States already infected and highly transmissible variants rapidly emerging, it is highly probable that post- and presymptomatic people will form an important fraction of those seeking dental care. Salivary carriage rates in these populations are not known. Moreover, although preventing transmission is critical for controlling spread, the efficacy of mouthrinses in reducing oral viral load is poorly studied.

Methods

The authors recruited 201 asymptomatic, presymptomatic, postsymptomatic, and symptomatic people and measured copy numbers of SARS-CoV-2 in unstimulated saliva using real-time reverse transcriptase quantitative polymerase chain reaction. Subsequently, the authors inducted 41 symptomatic people into a randomized, triple-blinded study and instructed them to rinse with saline, 1% hydrogen peroxide, 0.12% chlorhexidine, or 0.5% povidone-iodine for 60 seconds. The authors measured viral load 15 and 45 minutes after rinsing.

Results

Salivary SARS-CoV-2 was detected in 23% of asymptomatic, 60% of postsymptomatic, and 28% of presymptomatic participants. Neither carriage rate nor viral load correlated with COVID-19 symptomatology, age, sex, or race or ethnicity. All 4 mouthrinses decreased viral load by 61% through 89% at 15 minutes and by 70% through 97% at 45 minutes. The extent of reduction correlated significantly with initial viral load.

Conclusions

Nonsymptomatic people can pose a risk of transmitting the virus, and mouthrinses are simple and efficacious means of reducing this risk, especially when the load is less than 10⁴ copies per milliliter.

Practical Implications

At a time when resources are stretched, the findings of this study contribute to evidence-based selection of personal protection equipment and simple infection-control practices to reduce contagion at source.

This clinical trial was registered at ClinicalTrials.gov. The registration number is NCT04603794.

Impact of the Coronavirus on Providing Oral Health Care in the Netherlands

OBJECTIVE

Transmission of SARS-CoV-2 during oral health care is potentially increased compared to regular social activities. Specific amendments to the Dutch national infection control guidelines were promulgated. This study aimed to map the impact of the coronavirus pandemic on providing oral health care during the first wave of the coronavirus pandemic in 2020 in the Netherlands.

METHODS

A cross-sectional web-based survey was sent via email to a representative sample of dental hygienists and dentists in the Netherlands.

RESULTS

Of the 1700 oral health care practitioners approached, 440 (25.9%) responded to the survey. Patient access to oral health care was severely restricted during the lockdown in the spring of 2020. A total of 1.6% of the oral health care practitioners had laboratory-confirmed COVID-19 during the study period, although this is likely to be an underrepresentation due to limited access to testing at that time. Over half of the participants perceived an increased risk of virus transmission during aerosol-generating treatments in their practices. A large majority (65.0%-87.1%) of the oral health care practitioners followed the COVID-19-specific amendments to the national infection control guidelines. Compared to the pre-pandemic period, additional personal protective equipment and protocols were applied. Factors related with compliance with the additional recommendations were age, employment status, and occupation.

CONCLUSIONS

The pandemic had a profound impact on both the accessibility and practice of oral health care. This survey study found that most Dutch oral health care practitioners paid extra attention to hygiene and infection control. Also, a low number of COVID-19 infections detected amongst Dutch oral health care practitioners was reported in the Netherlands. These overall outcomes suggest that safe oral health care can be provided when following the current infection control recommendations.

Experience of patients diagnosed as asymptomatic COVID-19 after dental treatment

Background

The potential risk of coronavirus disease 2019 (COVID-19) transmission from asymptomatic COVID-19 patients is a concern in dental practice. However, the impact of this risk is not well documented to date. This report describes our dental clinical experience with patients who did not exhibit symptoms of COVID-19 but were later confirmed as positive for COVID-19.

Case presentation

Of the 149,149 patients who visited the outpatient clinic of KNUDH and the 3291 patients who visited the Oral and Maxillofacial Surgery Clinic of KNUH, 3 were later confirmed as having COVID-1 between 1 February 2020 and 28 February 2021. Owing to close contact with these patients during their treatments, 46 dental and medical staff had to undergo quarantine from the date of the patients’ confirmation of COVID-19 infection.

Conclusion

The presented cases showed the potential existence of asymptomatic COVID-19 patients after dental treatment with aerosol-generating procedures. Clinicians should be aware of the infection prevention measures and try to protect healthcare personnel from secondary infection of COVID-19 during dental treatments.

Ultrasonic scaling in COVID-era dentistry: A quantitative assessment of aerosol spread during simulated and clinical ultrasonic scaling procedures

Objective

Healthcare agencies recommend limited use of aerosol‐generating procedures to mitigate disease (COVID‐19) transmission. However, total dispersion patterns of aerosols, particularly respirable droplets, via dental ultrasonic units is unclear. The purpose of this study was to characterize and map total spatter, droplet and aerosol dispersion during ultrasonic scaling in simulated and clinical contexts.

Methods

Ultrasonic scaling was performed on dental simulation units using methylene blue dye‐stained water. All resultant stain profiles were photoanalysed to calculate droplet size and travel distance/direction. Airborne particle concentrations were also documented 0–1.2 m (0–4ft.) and 1.2–2.4 m (4–8ft.) from patients during in vivo ultrasonic scaling with a saliva ejector.

Results

Stain profiles showed droplets between 25 and 50µm in diameter were most common, with smaller droplets closer to the mouth. In‐vivo particle concentrations were uniformly low. The smallest (<1 µm, PM1) and largest (>10 µm, PM10+) particles were most common, especially within 1.2 m (4ft.) of the patient. Respirable particles (PM2.5) were uncommon.

Conclusions

Tests showed the highest concentration of small droplets in zones nearest the patient. While uncommon, particles were detected up to 2.4 m (8ft.) away. Furthermore, observed particle sizes were consistent with those that can carry infectious agents. Efforts to mitigate the spread of inhalable aerosols should emphasize proximate regions nearest the procedure, including personal protective equipment and the use of evacuation devices.