Aerosol transmission for SARS-CoV-2 in the dental practice. A review by SIdP Covid-19 task-force

Oral emergencies at Strasbourg teaching hospitals during the COVID-19 lockdown: Patient care circuits, typologies, and profiles

Purpose of research

We aimed to describe the type of emergencies as well as the population treated for oral emergencies at the Pôle de Médecine et Chirurgie Bucco-Dentaires (Dental Medicine and Surgery Center) of Strasbourg during the COVID-19 lockdown period from March 17 to May 9, 2020.

Information on patient care circuits as well as the demographic and clinical data concerning all those who accessed the Center during the study period were collected by questionnaire and from medical files. Pain was rated on a numerical scale from 0 to 10. Diagnoses and treatments provided were divided into clinically relevant classes. During the forty-two days of activity, 2,470 patients were seen and 94.2 percent of them were treated. A constant increase in activity, almost doubling between the beginning and the end of the period, was observed. Pain with an intensity greater than or equal to 5 on the scale was reported by 77.9 percent of patients; pain greater than or equal to 7 by 52.5 percent of patients. Coordination between the various general practice and hospital organizations is necessary to deal with oral emergencies, considering the high number of patients concerned and the associated pain level. This coordination was particularly effective during the COVID-19 lockdown, which led to a massive and constantly increasing recourse to emergency dental care. We were able to describe and detail the consultations for oral emergencies and confirm that the intense associated pain did not allow treatment to be postponed.

The impact of COVID-19 on Italian dentists: A cross-sectional survey on 2443 participants

OBJECTIVE

To evaluate the impact of COVID-19 pandemic among a sample of Italian dentists in terms of infection, strategies for infection control, organization of the dental clinic, attitude, and behavior.

MATERIAL AND METHODS

This was a cross-sectional survey. The sample consisted of 8000 Italian dentists selected among 63,375 using a computerized random sampling method. An electronic informed consent had to be signed. The questionnaire categories were on demographic, infection risk management, organization, and dentists' attitude and behavior. Geographic macro-areas were used for subgroup analysis.

RESULTS

Among 8000 invited dentists, 2443 agreed to participate to the survey (30.6%). Mean age was 51.2 years, women were 34.5%. A total of 6.1% self-reported COVID-19 experience and higher rate of infection was reported in north Italy compared to the south (p < 0.05). FFP2/FFP3 respirators (97.1%) and visors (97.4%) were used by almost all dentists. While, natural ventilation and mouthwashes were the most frequent approaches used to reduce the infection risk. Most of the dentists reported positive attitude, nevertheless 83.6% felt an increased responsibility.

CONCLUSION

The self-reported COVID-19 prevalence was 6.1% with some differences among geographic areas. COVID 19 had a deep impact on preventive strategies, dental office organization, and behavior within this sample.

The "new normal" of hygiene measures at the end of the COVID-19 epidemic: a survey among French dentists

OBJECTIVES

The COVID-19 epidemic upset the standards in terms of hygiene and protection in the dental office, bringing additional precautions for dentists. The objective of our study was to draw the "new normal" of hygiene measures at the end of the COVID-19 epidemic.

MATERIALS AND METHODS

A self-administered questionnaire about transitional recommendations for oral care in the context of the COVID-19 epidemic was published online in private groups dedicated to French dentists.

RESULTS

The 246 respondents understood the reasons behind those recommendations, since 10 out of 11 measures reached a mean score greater than 2.5 on a 0 (not at all) to 4 (absolutely) scale when it came to determining whether the measure made the practitioner feel safe and ensured patient safety. Besides, more of the respondents intended to maintain the measures than they were to apply them before the epidemic.

CONCLUSIONS

The COVID-19 epidemic reshaped the relationship to hygiene and protection measures in the context of dental practices. The "new normal" of hygiene measures at the end of the COVID-19 epidemic will probably involve more protective measures than before.

CLINICAL RELEVANCE

These results constitute interesting avenues for public health deliberation, which would make it possible to best adapt future health recommendations in order to define the "new normal" of hygiene measures in dental practices at the end of the COVID-19 epidemic. Therefore, it could have an impact on all practitioners in their clinical activities.

Ensemble deep honey architecture for COVID-19 prediction using CT scan and chest X-ray images

Recently, the infectious disease COVID-19 remains to have a catastrophic effect on the lives of human beings all over the world. To combat this deadliest disease, it is essential to screen the affected people quickly and least inexpensively. Radiological examination is considered the most feasible step toward attaining this objective; however, chest X-ray (CXR) and computed tomography (CT) are the most easily accessible and inexpensive options. This paper proposes a novel ensemble deep learning-based solution to predict the COVID-19-positive patients using CXR and CT images. The main aim of the proposed model is to provide an effective COVID-19 prediction model with a robust diagnosis and increase the prediction performance. Initially, pre-processing, like image resizing and noise removal, is employed using image scaling and median filtering techniques to enhance the input data for further processing. Various data augmentation styles, such as flipping and rotation, are applied to capable the model to learn the variations during training and attain better results on a small dataset. Finally, a new ensemble deep honey architecture (EDHA) model is introduced to effectively classify the COVID-19-positive and -negative cases. EDHA combines three pre-trained architectures like ShuffleNet, SqueezeNet, and DenseNet-201, to detect the class value. Moreover, a new optimization algorithm, the honey badger algorithm (HBA), is adapted in EDHA to determine the best values for the hyper-parameters of the proposed model. The proposed EDHA is implemented in the Python platform and evaluates the performance in terms of accuracy, sensitivity, specificity, precision, f1-score, AUC, and MCC. The proposed model has utilized the publicly available CXR and CT datasets to test the solution's efficiency. As a result, the simulated outcomes showed that the proposed EDHA had achieved better performance than the existing techniques in terms of Accuracy, Sensitivity, Specificity, Precision, F1-Score, MCC, AUC, and Computation time are 99.1%, 99%, 98.6%, 99.6%, 98.9%, 99.2%, 0.98, and 820 s using the CXR dataset.

A Survey on forensic odontologists' activity in Italy during the COVID-19 pandemic

Few information on virus contagion at the beginning of the covid-19 pandemic led to severe restrictions in the dental and forensic activity in Italy, the introduction of procedural guidelines and implementation of preventive measures. A specific survey on Italian forensic odontologists (FOds) activity was conducted to investigate the COVD-19 pandemic impact on daily practices, the preventive measures adopted to manage the risks of contagion procedures performed on living and dead people and the possible peculiar cases that required the intervention of a medical examiner. A total of 122 FOds answered, mostly males over 46 years coming from northern Italy. The results highlight the lack of specific guidelines for the procedures on living people compared to those on the dead but the regulations for the daily clinical practice resulted more than sufficient: in fact, more than 80% of FOds adopted the preventive and safety measures provided for dental practices. The forensic activity significantly decreased during the initial period (more than 75%) and gradually normalized to pre-pandemic numbers in approximately 50% of cases after the implementation of the vaccination campaign. 13 cases of occupational contagion have been reported, most of them (more than 85%) in northern and central Italy. In two cases members of the dental staff sued the employer for responsibility in the contagion. The decrease of the overall ID activity during the pandemic time can be more likely attributed to the of the dental data than the real impact of the pandemic regulations. The use of telematic tools, such as teleconferences, for many procedures proved to be an important resource useful for application even in post-pandemic times.

Microbial Air Contamination in a Dental Setting Environment and Ultrasonic Scaling in Periodontally Healthy Subjects: An Observational Study

The risk of microbial air contamination in a dental setting, especially during aerosol-generating dental procedures (AGDPs), has long been recognized, becoming even more relevant during the COVID-19 pandemic. However, individual pathogens were rarely studied, and microbial loads were measured heterogeneously, often using low-sensitivity methods. Therefore, the present study aimed to assess microbial air contamination in the dental environment, identify the microorganisms involved, and determine their count by active air sampling at the beginning (T0), during (T1), and at the end (T2) of ultrasonic scaling in systemically and periodontally healthy subjects. Air microbial contamination was detected at T0 in all samples, regardless of whether the sample was collected from patients treated first or later; predominantly Gram-positive bacteria, including Staphylococcus and Bacillus spp. and a minority of fungi, were identified. The number of bacterial colonies at T1 was higher, although the species found were similar to that found during the T0 sampling, whereby Gram-positive bacteria, mainly Streptococcus spp., were identified. Air samples collected at T2 showed a decrease in bacterial load compared to the previous sampling. Further research should investigate the levels and patterns of the microbial contamination of air, people, and the environment in dental settings via ultrasonic scaling and other AGDPs and identify the microorganisms involved to perform the procedure- and patient-related risk assessment and provide appropriate recommendations for aerosol infection control.

Can aerosols-generating dental, oral and maxillofacial, and orthopedic surgical procedures lead to disease transmission? An implication on the current COVID-19 pandemic

Various dental, maxillofacial, and orthopedic surgical procedures (DMOSP) have been known to produce bioaerosols, that can lead to the transmission of various infectious diseases. Hence, a systematic review (SR) aimed at generating evidence of aerosols generating DMOSP that can result in the transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), further investigating their infectivity and assessing the role of enhanced personal protective equipment (PPE) an essential to preventing the spreading of SARS-CoV-2 during aerosol-generating procedures (AGPs). This SR was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement (PRISMA) guidelines based on a well-designed Population, Intervention, Comparison, Outcomes and Study (PICOS) framework, and various databases were searched to retrieve the studies which assessed potential aerosolization during DMOSP. This SR included 80 studies (59 dental and 21 orthopedic) with 7 SR, 47 humans, 5 cadaveric, 16 experimental, and 5 animal studies that confirmed the generation of small-sized < 5 μm particles in DMOSP. One study confirmed that HIV could be transmitted by aerosolized blood generated by an electric saw and bur. There is sufficient evidence that DMOSP generates an ample amount of bioaerosols, but the infectivity of these bioaerosols to transmit diseases like SARS-CoV-2 generates very weak evidence but still, this should be considered. Confirmation through isolation and culture of viable virus in the clinical environment should be pursued. An evidence provided by the current review was gathered by extrapolation from available experimental and empirical evidence not based on SARS-CoV-2. The results of the present review, therefore, should be interpreted with great caution.

COVID-19 transmission in dental and oral/maxillofacial surgical practice during pandemic: questionnaire survey in 51 university hospitals in Japan

Background

The coronavirus disease 2019 (COVID-19) pandemic has become a major public health problem. Dental procedures that generate aerosols are considered to impose a high risk of infection; therefore, dental professionals, such as dentists and dental hygienists, may be at high risk of viral transmission. However, few studies have reported COVID-19 clusters in dental care settings.

Aim

To investigate whether dental and oral/maxillofacial procedures are associated with the occurrence of COVID-19 clusters and measures taken to prevent nosocomial infection in dental clinics.

Methods

An online questionnaire survey on clinical activities (administrative control), infection control measures (environmental/engineering control, personal protective equipment, etc.), and confirmed or probable COVID-19 cases among patients and clinical staff was administered to the faculties of the dental and oral/maxillofacial surgical departments of university hospitals.

Findings

Fifty-one faculty members completed the questionnaire. All members were engaged in the treatment of dental and oral surgical outpatients and actively implemented standard precautions. Fourteen faculty members treated patients with COVID-19, but no infections transmitted from the patients to the medical staff were observed. In seven facilities, patients were found to have the infection after treatment (medical staff came in close contact), but there was no transmission from patients to medical staff. Four facilities had medical staff with infections, but none of them exhibited disease transmission from staff to patients.

Conclusion

COVID-19 clusters are unlikely to occur in dental and oral surgical care settings if appropriate protective measures are implemented.

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.

Dispersion of Aerosols Generated during Dental Therapy

The novel coronavirus pandemic has resulted in an urgent need to study the risk of infection from aerosols generated during dental care and to conduct a review of infection controls. However, existing studies on aerosol particles related to dental treatment have mainly evaluated only the scattering range. Few studies have been conducted on the specifics of the generation of aerosol particles in clinical settings, their mechanisms and patterns of distribution throughout open or enclosed spaces, the duration that they remain suspended in air, and the amount and size of particles present. To minimize the influence of background particles, laser lights, a high-sensitivity camera, and particle counters were used in a large super clean laboratory to investigate the dynamics of aerosols generated during the operation of dental micromotors. The results indicate that aerosols tend to scatter upward immediately after generation and then gradually disperse into the surroundings. Most of the particles are less than 5 µm in size (only a few are larger), and all particles are widely distributed over the long term. Our research clearly elucidates that aerosols produced in dental care are distributed over a wide area and remain suspended for a considerable time in dental clinics before settling.

COVID-19 and dental workers: The Italian Society of Periodontology and Implantology (SIdP) survey

Objectives

To evaluate the proportion of COVID‐19 infections among a population of Italian Dental workers across different geographical area of Italy and to analyze the impact of both the preventive measures/strategies adopted and the psychological influences.

Subjects and Methods

The current cross‐sectional survey was administered with a web‐based form. To be eligible for the study, participants had to be 18 years and being dentists or dental hygienists members of the Italian Society of Periodontology and Implantology (SIdP). A 23‐item questionnaire concerning positiveness to COVID‐19, clinical strategies and psychological attitude within the pandemic was administered. Sub‐group analysis was conducted according to geographical macro‐area.

Results

A total of 790 dentists and dental hygienists were included. A total of 4.7% participants developed a positive diagnosis to COVID‐19. The Northwest of Italy experienced almost double of COVID‐19‐positive participants (p < 0.05). Preoperatory mouthwashes together with natural air change/ventilation were the most frequent approaches used to prevent COVID‐19 outbreak. Positive and proactive attitudes were predominant among participants. Only a reduced proportion feels some concerns for the future.

Conclusions

Prevalence of positive COVID‐19 among dental workers in Italy was double in Northwest area in comparison with the whole country proportion. Preventive strategies comprise mainly ultrasound reduction and preoperative mouthwashes.

Biosafety devices to control the spread of potentially contaminated dispersion particles. New associated strategies for health environments

Dental procedures produce a large amount of spatter and aerosols that create concern for the transmission of airborne diseases, such as Covid-19. This study established a methodology with the objective of evaluating new associated strategies to reduce the risk of cross-transmission in a health environment by simulating spread of potentially contaminated dispersion particles (PCDP) in the environment. This crossover study, was conducted in a school clinic environment (4 clinics containing 12 dental chairs each). As a positive control group (without barriers), 12 professionals activated at the same time the turbine of dental drill, for one minute, with a bacterial solution (Lactobacillus casei Shirota, 1.5x10⁸ CFU/mL), which had been added in the cooling reservoir of the dental equipment. In the experimental groups, the professionals made use of; a) an individual biosafety barrier in dentistry (IBBD) which consists of a metal support covered by a disposable PVC film barrier; b) a Mobile Unit of Disinfection by Ultraviolet-C, consisting of 8 UV lamps-C of 95W, of 304μW/cm² of irradiance each, connected for 15 minutes (UV-C) and; c) the association between the two methods (IBBD + UV-C). In each clinic, 56 Petri dishes containing MRS agar were positioned on the lamps, benches and on the floor. In addition, plates were placed prior to each test (negative control group) and plates were also placed in the corridor that connects the four clinics. In the groups without barrier and IBBD + UV-C the passive air microorganisms in Petri dishes was also evaluated at times of 30, 60, 90 and 120 minutes after the end of the dental’s drill activation. The mean (standard deviation) of CFU of L. casei Shirota for the positive control group was 3905 (1521), while in the experimental groups the mean using the IBBD was 940 (466) CFU, establishing a reduction on average, of 75% (p<0.0001). For the UV-C group, the mean was 260 (309) CFU and the association of the use of IBBD + UV-C promoted an overall average count of 152 (257) CFU, establishing a reduction on average of 93% and 96%, respectively (p<0.0001). Considering these results and the study model used, the individual biosafety barrier associated with UV-C technology showed to be efficient strategies to reduce the dispersion of bioaerosols generated in an environment with high rate of PCDP generation and may be an alternative for the improvement of biosafety in different healthy environment.

Effects of Natural Ventilation and Saliva Standard Ejectors during the COVID-19 Pandemic: A Quantitative Analysis of Aerosol Produced during Dental Procedures

The novel Coronavirus Disease 2019 (COVID-19) pandemic has renewed attention to aerosol-generating procedures (AGPs). Dental-care workers are at high risk of contamination by SARS-CoV-2. The aim of this study was to evaluate the efficacy of standard saliva ejectors and natural ventilation in reducing particulate matter (PM) concentration during different routine dental procedures in the pandemic period. The DustTrak monitor was used to measure PM1, PM2.5, PM10, and breathable (<4 microns) total dust during 14 procedures performed with and without the presence of natural ventilation in a dental unit. Moreover, measurements were performed near the practitioners or near the standard saliva ejectors during the different procedures. In the latter condition, reduced levels of PM10 were recorded (82.40 ± 9.65 μg/m³ vs. 50.52 ± 0.23 μg/m³). Moreover, higher levels of PM (53.95 ± 2.29 μg/m³ vs. 27.85 ± 0.14 μg/m³) were produced when the dental unit's windows were open. At the same time, the total level of PM were higher during scaling than during other procedures (data suggest not to adopt natural ventilation-both window and door opened-during dental procedures). It was also demonstrated that the use of standard saliva ejectors can considerably reduce the total released amount of PM10.

Should we test asymptomatic children for SARS-CoV-2?

Design Cross-sectional study.

Sample selection This study included 921 children (471 male, 450 female) due to receive either routine dental care involving aerosol generating procedures or comprehensive dental care under general anaesthetic. Data was collected at a paediatric dental clinic associated with the University of Illinois, Chicago. Patients were screened by a telephone questionnaire assessing for coronavirus disease 2019 (COVID-19) or severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Asymptomatic patients and those with no known disease exposure went on to receive a reverse transcription polymerase chain reaction (RT-PCR) test for SARS-CoV-2, the causative pathogen for COVID-19. Those displaying symptoms of COVID-19 or who had potentially been exposed to the virus or disease were not included in this study and were referred for onwards medical advice.

Data analysis Electronic dental records were accessed to retrieve patient demographics, insurance type, dental diagnosis and past medical history. The percentage of positive SARS-CoV-2 test results was calculated for each category. Positive and negative test results were compared appropriately for both categorical and continuous variables, with significance reached when p <0.05. SPSS version 27 was used for statistical analysis.

Results This study found the positivity rate for SARS-CoV-2 to be 2.3% (21/921) in asymptomatic dental patients aged under 18 years. Age, insurance type, medical history and dental diagnosis were comparable in both positive and negative test result groups. The Hispanic/Latinx population had a higher percentage (3.1%) of positive tests than other groups. More male patients tested positive for SARS-CoV-2 (13 male, 8 female), but this was not statistically significant.

Conclusions RT-PCR testing identified children carrying SARS-CoV-2 who had been cleared to attend an appointment following a screening questionnaire.

Dental Education in the Time of COVID-19 Pandemic: Challenges and Recommendations

Moving within the second wave of the coronavirus (COVID-19) pandemic, dental education delivery has been profoundly affected by this crisis, so has the structure, evaluation, and future of dental education. Both pre-clinical and clinical dental education have experienced challenges ranging from fully online educational content to limited dental training for senior dental students. This crisis appears to be a tipping point that produced confusion in dental teaching especially clinical sciences. Although medical institutions immediately started to adapt to the unexpected COVID-19 crisis, dental and oral health educational services are profoundly impaired due to the dental team's propinquity to the patient and the aerosols generated during routine dental therapeutic procedures. Dental students unlike other medical students are considered to be at the highest risk due to the nature of their clinical training that includes working in the oral cavity of patients using aerosol-generating equipment. Some dental schools have taken the leadership and documented their modifications during this pandemic; however, there is a serious need for further investigation and wide range screening of the situation in the dental schools during the COVID-19 crisis. The aim of this mini-review is to present these challenges and how academic dental institutions have implemented strategies to overcome them.

Coronavirus disease 2019 (COVID-19) vaccines: A concise review

The development of a successful vaccine against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the agent of coronavirus disease 2019 (COVID-19), in an unmatched period of ten months, is a tribute to human ingenuity in the face of a vicious pandemic. A return to pre-pandemic "normalcy" depends on the successful delivery of the vaccine to a majority (~70%) so as to develop herd immunity critical to arrest the community spread of infection. Vaccination against COVID-19 is particularly important for dentistry as the dental team works in an environment replete with aerosol-generating procedures (AGP) that facilitate virus spread. Hence, a COVID-19 vaccine is likely to be an obligatory requirement for the dental practice, and the latest addition to the extensive list of vaccines required for dental professionals for the safe delivery of dental care. Here, we review the currently available major candidate vaccines against SARS-CoV-2 and their benefits and risks. These include the vaccines developed on next-generation platforms (mRNA, DNA, and viral vector vaccines), and the classic platforms (the live-attenuated virus, and the protein subunit vaccines) The review concludes with a summary of impending issues and challenges facing the provision of COVID-19 vaccines for all stakeholders in dentistry.

A novel dental biosafety device to control the spread of potentially contaminated dispersion particles from dental ultrasonic tips

Strategies to return to dental practice in pandemic times is a new challenge due to the generation and spread of potentially contaminated dispersion particles (PCDP) that may contain the SARS-CoV-2, the etiological factor of the COVID-19 disease. Due to the significant dispersion of PCDP in the dental environment, the use of equipment such as ultrasonic tips have been inadvisable during the pandemic. Several clinical procedures, however, benefit from the use of such equipment. Thus, using a microbial dispersion model of PCDP, the aim of this study was to compare the dispersion caused by the dental drill (DD) an ultrasonic tip (UT) alone and the UT coupled with a Spray control (SC) device. The DD, UT (with or without the SC) were activated for one minute having had the water from the reservoir replaced with a suspension of Lactobacillus casei Shirota (1.5 x 10⁸ CFU/mL). Petri dishes containing MRS agar were positioned at 50cm, 100cm and 150cm from the headrest of the dental chair at different angles (0 degree and 90 degrees). At 50 cm, the mean CFU (standard deviation) of L. casei Shirota was 13554.60 (4071.03) for the DD, 286.67 (73.99) for the US (97.89% reduction), and 4.5 (0.58) CFU for the UT-SC (p < 0.0001), establishing a further 98.43% reduction between UT and UT with SC. The UT with SC model proved effective in reducing dispersion from the UT, endorsing its use as an additional strategy to reduce PCDP in the dental environment in times of pandemic.