Interventions to Reduce Aerosolized Microbes in Dental Practice: A Systematic Review with Network Meta-analysis of Randomized Controlled Trials

Cetylpyridinium chloride and chlorhexidine show antiviral activity against Influenza A virus and Respiratory Syncytial virus in vitro

BACKGROUND

The oral cavity is the site of entry and replication for many respiratory viruses. Furthermore, it is the source of droplets and aerosols that facilitate viral transmission. It is thought that appropriate oral hygiene that alters viral infectivity might reduce the spread of respiratory viruses and contribute to infection control.

MATERIALS AND METHODS

Here, we analyzed the antiviral activity of cetylpyridinium chloride (CPC), chlorhexidine (CHX), and three commercial CPC and CHX-containing mouthwash preparations against the Influenza A virus and the Respiratory syncytial virus. To do so the aforementioned compounds and preparations were incubated with the Influenza A virus or with the Respiratory syncytial virus. Next, we analyzed the viability of the treated viral particles.

RESULTS

Our results indicate that CPC and CHX decrease the infectivity of both the Influenza A virus and the Respiratory Syncytial virus in vitro between 90 and 99.9% depending on the concentration. Likewise, CPC and CHX-containing mouthwash preparations were up to 99.99% effective in decreasing the viral viability of both the Influenza A virus and the Respiratory syncytial virus in vitro.

CONCLUSION

The use of a mouthwash containing CPC or CHX alone or in combination might represent a cost-effective measure to limit infection and spread of enveloped respiratory viruses infecting the oral cavity, aiding in reducing viral transmission. Our findings may stimulate future clinical studies to evaluate the effects of CPC and CHX in reducing viral respiratory transmissions.

The Impact of Hydrogen Peroxide (H2O2) Fumigation on Bacterial Levels in Dental Office Environments: A Randomized Clinical Trial Investigation

BACKGROUND

Fumigation with hydrogen peroxide has proven to be a highly effective approach to maintaining biological safety within dental offices. The main purpose of this research was to investigate the efficacy of hydrogen peroxide (H2O2) fumigation in reducing bacterial levels in dental office environments.

METHODS

The study involved 30 participants diagnosed with moderate caries decay (ICDAS 3 and 4) in their mandibular molars. Sixty Petri dishes (two per patient) with Columbia Agar and 5% Sheep Blood were opened at the beginning of the caries treatment. After the completion of caries treatment and tooth restoration, 30 plates (G1 group) were closed. Following this, a 20 min fumigation procedure with 6% hydrogen peroxide biosanitizer using a compressed air device was conducted. After the fumigation, the remaining plates were closed (G2 group). The total number of bacteria CFUs (colony-forming units) in the dental office air was determined using the Koch sedimentation method.

RESULTS

The total bacterial colony (TBC) level, measured in cfu/m3, demonstrated a significant decrease in the number of bacteria following room environment fumigation (163.1 ± 145.7; G2 group) compared to non-fumigated samples (817.2 ± 208.2; G1 group) (p < 0.001). The predominant bacteria observed in the microbiological plates before fumigation were Micrococcus and Bacillus species, found in 80% (24/30) and 60% (18/30) of the plates, respectively. Application of H2O2 room fumigation resulted in a significant reduction in bacterial numbers: 79.2% (5/30) for Micrococcus species (p < 0.001), 83.3% (3/30) for Bacillus species (p < 0.001), and 100% (0/30) for Staphylococcus arlettae (p < 0.05).

CONCLUSION

Fumigation with 6% H2O2 is an effective method for reducing bacterial counts in a dental office environment.

Effectiveness of interventions to reduce aerosol generation in dental environments: A systematic review

Certain dental procedures produce high levels of aerosols containing pathogenic microorganisms, posing a risk for the transmission of infections in dental settings. This study aimed to assess the effectiveness of various aerosol mitigation interventions during clinical dental procedures in real-world environments. A systematic literature search was conducted in PubMed/MEDLINE, Scopus, Web of Science, and Embase for English studies up to March 2023 according to the PRISMA guidelines. Only peer-reviewed controlled clinical trials (CCT) or randomized controlled trials (RCT) studies involving human subjects were included. The risk of bias of selected researches were evaluated by two independent authors using the Cochrane Collaboration tool. The literature search yielded 3491 articles, of which 42 studies met the inclusion criteria and were included in this study. Most studies evaluated bacterial contamination in bio-aerosols, while the viral and fungal contamination was assessed in only three studies. Overall, various approaches have been applied in reducing aerosol contamination in clinical scenarios, including high-volume evacuators (HVE), mouse rinses and rubber dams, air cleaning systems, and high-efficiency particulate air (HEPA) filters. The available evidence suggests that various aerosol mitigation strategies could be implemented to decrease the risk of cross-infection during clinical dental procedures in real-world environments. However, further clinical trials are necessary to establish statistical validity in measuring aerosol contamination and mitigation, as well as to evaluate the risk of infection transmission for viral and fungal contamination.

Effects of Chlorhexidine and Povidone-Iodine on the SARS-CoV-2 Load: A Systematic Review and Meta-analysis

The efficacy of mouthwash for reducing the viral load in patients with the novel coronavirus disease 2019 (COVID-19) remains unclear. This systematic review and meta-analysis comprehensively examined the effects of chlorhexidine (CHX) and povidone-iodine (PVP-I) on the viral load in patients with COVID-19. We performed methodological analysis, systematic review, and meta-analysis of included studies using the Comprehensive Meta-analysis Software. PubMed, EMBASE, Cochrane Library, and ProQuest were searched from December 1, 2019, to December 2, 2021. In total, we included 10 studies of 1,339 patients with COVID-19. Compared with the control group, both CHX and PVP-I significantly reduced the number of negative reverse-transcription polymerase chain reaction (RT-PCR) results (p<0.001) among COVID-19 patients. The CHX and PVP-I were effective on reducing the number of negative RT-PCR results in COVID-19 patients. Additional studies using adequate randomization methods and larger samples are warned.

Preprocedural Viral Load Effects of Oral Antiseptics on SARS-CoV-2 in Patients with COVID-19: A Systematic Review

(1) There are limited clinical trials to support the effectiveness of mouth rinses when used as a preprocedural rinse against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This systematic review aims to evaluate the efficacy of antiseptic mouth rinses as a preprocedural rinse in reducing SARS-CoV-2 oral viral load in-vivo. (2) Methods: A literature search was conducted through November 2022 for the following databases: PubMed, Web of Science, Cochrane Library, and Google Scholar. The evaluated outcomes were quantitative changes in viral load and the statistical significance of that change after using antiseptic mouth rinses. (3) Results: 14 randomized controlled trials (RCT) were selected for risk of bias assessment and data extraction. (4) Conclusion: Within the limits of this systematic review, preprocedural mouth rinses may significantly reduce SARS-CoV-2 in the mouth, thus, reducing the viral particles available for airborne dispersion. Preprocedural mouth rinses may be an effective strategy for reducing airborne SARS-CoV-2 dispersion in the environment. Their use may be a preventive strategy to reduce the spread of COVID-19 in selected medical and healthcare facilities, including dental clinics. Potential preprocedural mouth rinses are identified for use as an integral part of safe practice for healthcare protocols. This systematic review was registered with the National Institute for Health Research, international prospective register of systematic reviews (PROSPERO): CRD42022315177.

Is the effect of COVID-19 on periodontal treatment similar to that in general dental care and primary medical care? an observational study in Brazil

The present study aimed to analyze the effect of the COVID-19 pandemic on the rates of periodontal procedures, and provide a comparison with general dental care and primary medical care procedures carried out in the Brazilian Public Health System. The study had an ecological, retrospective design with data from 5,564 Brazilian municipalities (99.9%). A multilevel mixed-effects linear regression was used to analyze the longitudinal associations between the COVID-19 pandemic and the rate of procedures. There was a significant reduction in the number of periodontal procedures (Coef. -428.6 [95%CI -774.3/-82.9]) during the COVID-19 pandemic, although this reduction was no greater than that of medical and general dental procedures. Medical procedures witnessed the sharpest drop in procedures (Coef. -2831.5 [95%CI -3964.1/-1699.0]). A lower rate of general dental procedures was also identified during the pandemic (Coef. -2,110.6 [95%CI -3,400.8/-820.4]). The COVID-19 pandemic has had a negative effect on the rate of periodontal procedures carried out in the Brazilian Public Health System. The highest recutions were observed in general dental and medical procedures.

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.

Preprocedural mouthwashes for infection control in dentistry-an update

OBJECTIVES

Aerosols and splatter are routinely generated in dental practice and can be contaminated by potentially harmful bacteria or viruses such as SARS-CoV-2. Therefore, preprocedural mouthwashes containing antiseptic agents have been proposed as a potential measure for infection control in dental practice. This review article aims to summarize the clinical (and, if insufficient, preclinical) evidence on preprocedural mouthwashes containing antiseptic agents and to draw conclusions for dental practitioners.

METHODS

Literature on preprocedural mouthwashes for reduction of bacterial or viral load in dental aerosols was searched and summarized.

RESULTS

Preprocedural mouthwashes, particularly those containing chlorhexidine digluconate (CHX), cetylpyridinium chloride (CPC), or essential oils (EO), can significantly reduce the bacterial load in dental aerosols. With respect to viruses such as HSV-1, there are too little clinical data to draw any clear recommendations. On the other hand, clinical data is consolidating that CPC-containing mouthwashes can temporarily reduce the intraoral viral load and infectivity in SARS-CoV-2 positive individuals. Nevertheless, potential risks and side effects due to regular antiseptic use such as ecological effects or adaptation of bacteria need to be considered.

CONCLUSIONS

The use of preprocedural mouthwashes containing antiseptics can be recommended according to currently available data, but further studies are needed, particularly on the effects on other viruses besides SARS-CoV-2. When selecting a specific antiseptic, the biggest data basis currently exists for CHX, CPC, EO, or combinations thereof.

CLINICAL RELEVANCE

Preprocedural mouthwashes containing antiseptics can serve as part of a bundle of measures for protection of dental personnel despite some remaining ambiguities and in view of potential risks and side effects.

Impact of DHCWs' Safety Perception on Vaccine Acceptance and Adoption of Risk Mitigation Strategies

OBJECTIVES

To estimate the association between safety perception on vaccine acceptance and adoptions of risk mitigation strategies among dental health care workers (DHCWs).

METHODS

A survey was emailed to DHCWs in the New Jersey area from December 2020 to January 2021. Perceived safety from regular SARS-CoV-2 testing of self, coworkers, and patients and its association with vaccine hesitancy and risk mitigation were ascertained. Risk Mitigation Strategy (RiMS) scores were computed from groupings of office measures: 1) physical distancing (reduced occupancy, traffic flow, donning of masks, minimal room crowding), 2) personal protective equipment (fitted for N95; donning N95 masks; use of face shields; coverings for head, body, and feet), and 3) environmental disinfection (suction, air filtration, ultraviolet, surface wiping).

RESULTS

SARS-CoV-2 testing of dental professionals, coworkers, and patients were perceived to provide safety at 49%, 55%, and 68%, respectively. While dentists were least likely to feel safe with regular self-testing for SARS-CoV-2 (P < 0.001) as compared with hygienists and assistants, they were more willing than hygienists (P = 0.004; odds ratio, 1.79 [95% CI, 1.21 to 2.66]) and assistants (P < 0.001; odds ratio, 3.32 [95% CI, 1.93 to 5.71]) to receive the vaccine. RiMS scores ranged from 0 to 19 for 467 participants (mean [SD], 10.9 [2.9]). RiMS scores did not significantly differ among groups of DHCWs; however, mean RiMS scores were higher among those who received or planned to receive the COVID-19 vaccine than those with who did not (P = 0.004). DHCWs who felt safer with regular testing had greater RiMS scores than those who did not (11.0 vs. 10.3, P = 0.01).

CONCLUSIONS

Understanding DHCWs' perception of risk and safety is crucial, as it likely influences attitudes toward testing and implementation of office risk mitigation policies. Clinical studies that correlate risk perception and RiMS with SARS-CoV-2 testing are needed to demonstrate the effectiveness of RiMS in dental care settings.

KNOWLEDGE TRANSFER STATEMENT

Educators, clinicians, and policy makers can use the results of this study when improving attitudes toward testing and implementation of risk mitigation policies within dental offices, for current and future pandemics.

Efficacy of a Mouthwash Containing CHX and CPC in SARS-CoV-2-Positive Patients: A Randomized Controlled Clinical Trial

Soon after the outbreak of the coronavirus disease 2019 (COVID-19) pandemic, preprocedural mouthwashes were recommended for temporarily reducing intraoral viral load and infectivity of individuals potentially infected with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in order to protect medical personnel. Particularly, the antiseptic cetylpyridinium chloride (CPC) has shown virucidal effects against SARS-CoV-2 in vitro. Therefore, the aim of this randomized controlled clinical trial was to investigate the efficacy of a commercially available mouthwash containing CPC and chlorhexidine digluconate (CHX) at 0.05% each in SARS-CoV-2-positive patients as compared to a placebo mouthwash. Sixty-one patients who tested positive for SARS-CoV-2 with onset of symptoms within the last 72 h were included in this study. Oropharyngeal specimens were taken at baseline, whereupon patients had to gargle mouth and throat with 20 mL test or placebo (0.9% NaCl) mouthwash for 60 s. After 30 min, further oropharyngeal specimens were collected. Viral load was analyzed by quantitative reverse transcriptase polymerase chain reaction, and infectivity of oropharyngeal specimens was analyzed by virus rescue in cell culture and quantified via determination of tissue culture infectious doses 50% (TCID₅₀). Data were analyzed nonparametrically (α = 0.05). Viral load slightly but significantly decreased upon gargling in the test group (P = 0.0435) but not in the placebo group. Viral infectivity as measured by TCID₅₀ also significantly decreased in the test group (P = 0.0313), whereas there was no significant effect but a trend in the placebo group. Furthermore, it was found that the specimens from patients with a vaccine booster exhibited significantly lower infectivity at baseline as compared to those without vaccine booster (P = 0.0231). This study indicates that a preprocedural mouthwash containing CPC and CHX could slightly but significantly reduce the viral load and infectivity in SARS-CoV-2-positive patients. Further studies are needed to corroborate these results and investigate whether the observed reductions in viral load and infectivity could translate into clinically useful effects in reducing COVID-19 transmission (German Clinical Trials Register DRKS00027812).

Bibliometric analysis of the 100 most-cited dental articles on COVID-19

Objective: This study aimed to bibliometrically characterize the top 100 most cited (T100) dental articles about COVID-19. Materials and Method: In the present study, the Web of Science core collection database was used to identify the T100 dental articles on COVID-19 in the category of "Dentistry, Oral Surgery and Medicine'' on May 19, 2021. Among the included top most cited articles, the following parameters were recorded and bibliometrically analyzed as article title, publication date, authorship, institution and country of origin, journals, with its impact factor (IF) and quartile, number of citations, study design, study topic, and level of evidence (LOE). Results: The mean citation count of the T100 dental articles on COVID-19 was 32.77 ± 97.31. The T100 dental articles were published in 43 different journals. The number of citations was positively correlated with journal IF (p&lt;0.05; Spearman’s rank test). Four papers were cited more than 100 times. Although 521 authors from 32 different countries contributed to the articles, only 28% had international collaborations. The most productive countries were the USA and China. Of the T100 articles, 50% were of LOE VII and 32% LOE V. The most common study type was narrative reviews (n=38) followed by cross-sectional studies (n=26). Conclusion: This bibliometric analysis of the T100 dental articles on COVID-19 presents the current status, relationships between disciplines, and popular research trends. According to our analysis, the majority of the published articles are of low level of evidence. The establishment of further international cooperation between researchers may improve the scientific quality of future dentistry articles on COVID-19.

Virucidal activity in vitro of mouthwashes against a feline coronavirus type II

Transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can occur through saliva and aerosol droplets deriving from the upper aerodigestive tract during coughing, sneezing, talking, and even during oral inspection or dental procedures. The aim of this study was to assess in vitro virucidal activity of commercial and experimental mouthwashes against a feline coronavirus (FCoV) strain. Commercial and experimental (commercial-based products with addition of either sodium dodecyl sulfate (SDS) or thymus vulgaris essential oil (TEO) at different concentrations) mouthwashes were placed in contact with FCoV for different time intervals, that is, 30 s (T30), 60 s (T60), and 180 s (T180); subsequently, the virus was titrated on Crandell Reese Feline Kidney cells. An SDS-based commercial mouthwash reduced the viral load by 5 log10 tissue culture infectious dose (TCID)₅₀ /50 µl at T30 while a cetylpyridinium (CPC)-based commercial mouthwash was able to reduce the viral titer of 4.75 log10 at T60. Furthermore, five experimental mouthwashes supplemented with SDS reduced the viral titer by 4.75-5 log10 according to a dose- (up to 4 mM) and time-dependent fashion.

Clinical Efficacy of an Extraoral Dental Evacuation Device in Aerosol Elimination During Endodontic Access Preparation

INTRODUCTION

Coronavirus disease 2019 (COVID-19) has caused many concerns in the dental field regarding aerosol production and the transmission of the severe acute respiratory syndrome coronavirus 2 virus during dental procedures. Because of the abrupt arrival of COVID-19, there has been little to no published research on the efficacy of dental suction devices in the removal of aerosols related to COVID-19 or the impact extraoral suction devices have on patients' experiences. Therefore, the aim of this study was to measure the amount of aerosol produced during endodontic access preparation for root canal therapy with and without the use of an extraoral dental suction device and to gather information through a survey regarding patients' experiences.

METHODS

Aerosol measurements were recorded in 8 closed-door resident operatories each morning before the procedures, 1 minute during the procedure, and 15 minutes after the access was complete. The CICADA DTO KN99 Extraoral Dental Suction Device (Foshan Cicada, Guangdong, China) was placed in 4 operatories, whereas no DTO extraoral suction device was used in 4 control operatories. Twenty cases with DTO and 20 cases without it were completed, and the data were analyzed.

RESULTS

Aerosols 1 minute after access were higher with and without DTO. There was a significant reduction after 15 minutes when the DTO device was used compared to high-volume suction alone. Composite and zirconia produced the most aerosols at 1 minute.

CONCLUSION

The results show that the reduction of aerosols is enhanced when the extraoral suction device is used in combination with traditional high-volume evacuation. However, the increased noise level when using the device can have a negative impact on patients' dental experience.

The Pragmatic Return to Effective Dental Infection Control Through Triage and Testing (PREDICT) Study: Protocol for a Prospective Clinical Study in the National Dental Practice-Based Research Network

BACKGROUND

Dental practice has been greatly affected by the COVID-19 pandemic. As SARS-CoV-2 infection is transmitted by respiratory fluids, dental practice techniques, which include aerosol-generating procedures, can increase the risk of transmission causing heightened safety concerns for both dental health care workers (DHCWs) and patients. These concerns have resulted in the reduction in patient volume and the available workforce within dental practices across the United States. Standardized methods for COVID-19 triage and testing may lead to increased safety and perceptions of safety for DHCWs and their patients and promote willingness to provide and access oral health care services.

OBJECTIVE

This study is designed to develop procedures that test the feasibility of enhanced COVID-19 triage and testing in dental offices. It will provide preliminary data to support a larger network-wide study grant application aimed at developing protocols to address safety concerns of patients and DHCWs in a peri-COVID-19 pandemic era.

METHODS

The feasibility study is being conducted in 4 private dental practices, each of which has a dentist member of the National Dental Practice-Based Research Network. Participants include the DHCWs and patients of the dental practice. Study procedures include completion of COVID-19 triage, completion of COVID-19 testing (point-of-care [POC] or laboratory-based [LAB] SARS-CoV-2 viral, antigen, and antibody tests based on office designation), and administration of perception and attitude surveys for participating DCHWs and patients of the dental practice over a defined study period. The office designation and the participant's role in the practice determines which testing protocol is executed within the office. There are 4 study groups following 4 distinct protocols: (1) POC DHCWs, (2) POC patients, (3) LAB DHCWs, and (4) LAB patients.

RESULTS

Data collection began in December of 2021 and concluded in March 2022. Study results are expected to be published in fall 2022.

CONCLUSIONS

The results of this feasibility study will help identify the viability and functionality of COVID-19 triage and testing in dental practices and inform a larger network-wide study grant application that develops protocols that address safety concerns of patients and DHCWs in a COVID-19 environment.

TRIAL REGISTRATION

ClinicalTrials.gov NTC05123742; https://clinicaltrials.gov/ct2/show/NCT05123742?term=NCT05123742.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/38386.

Preprocedural mouth rinses for preventing transmission of infectious diseases through aerosols in dental healthcare providers

BACKGROUND

Aerosols and spatter are generated in a dental clinic during aerosol-generating procedures (AGPs) that use high-speed hand pieces. Dental healthcare providers can be at increased risk of transmission of diseases such as tuberculosis, measles and severe acute respiratory syndrome (SARS) through droplets on mucosae, inhalation of aerosols or through fomites on mucosae, which harbour micro-organisms. There are ways to mitigate and contain spatter and aerosols that may, in turn, reduce any risk of disease transmission. In addition to personal protective equipment (PPE) and aerosol-reducing devices such as high-volume suction, it has been hypothesised that the use of mouth rinse by patients before dental procedures could reduce the microbial load of aerosols that are generated during dental AGPs.

OBJECTIVES

To assess the effects of preprocedural mouth rinses used in dental clinics to minimise incidence of infection in dental healthcare providers and reduce or neutralise contamination in aerosols.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search date was 4 February 2022.

SELECTION CRITERIA

We included randomised controlled trials and excluded laboratory-based studies. Study participants were dental patients undergoing AGPs. Studies compared any preprocedural mouth rinse used to reduce contaminated aerosols versus placebo, no mouth rinse or another mouth rinse. Our primary outcome was incidence of infection of dental healthcare providers and secondary outcomes were reduction in the level of contamination of the dental operatory environment, cost, change in mouth microbiota, adverse events, and acceptability and feasibility of the intervention.

DATA COLLECTION AND ANALYSIS

Two review authors screened search results, extracted data from included studies, assessed the risk of bias in the studies and judged the certainty of the available evidence. We used mean differences (MDs) and 95% confidence intervals (CIs) as the effect estimate for continuous outcomes, and random-effects meta-analysis to combine data  MAIN RESULTS:  We included 17 studies with 830 participants aged 18 to 70 years. We judged three trials at high risk of bias, two at low risk and 12 at unclear risk of bias.  None of the studies measured our primary outcome of the incidence of infection in dental healthcare providers.  The primary outcome in the studies was reduction in the level of bacterial contamination measured in colony-forming units (CFUs) at distances of less than 2 m (intended to capture larger droplets) and 2 m or more (to capture droplet nuclei from aerosols arising from the participant's oral cavity). It is unclear what size of CFU reduction represents a clinically significant amount. There is low- to very low-certainty evidence that chlorhexidine (CHX) may reduce bacterial contamination, as measured by CFUs, compared with no rinsing or rinsing with water. There were similar results when comparing cetylpyridinium chloride (CPC) with no rinsing and when comparing CPC, essential oils/herbal mouthwashes or boric acid with water. There is very low-certainty evidence that tempered mouth rinses may provide a greater reduction in CFUs than cold mouth rinses. There is low-certainty evidence that CHX may reduce CFUs more than essential oils/herbal mouthwashes. The evidence for other head-to-head comparisons was limited and inconsistent.  The studies did not provide any information on costs, change in micro-organisms in the patient's mouth or adverse events such as temporary discolouration, altered taste, allergic reaction or hypersensitivity. The studies did not assess acceptability of the intervention to patients or feasibility of implementation for dentists.  AUTHORS' CONCLUSIONS: None of the included studies measured the incidence of infection among dental healthcare providers. The studies measured only reduction in level of bacterial contamination in aerosols. None of the studies evaluated viral or fungal contamination. We have only low to very low certainty for all findings. We are unable to draw conclusions regarding whether there is a role for preprocedural mouth rinses in reducing infection risk or the possible superiority of one preprocedural rinse over another. Studies are needed that measure the effect of rinses on infectious disease risk among dental healthcare providers and on contaminated aerosols at larger distances with standardised outcome measurement.

Is Lipid Specificity Key to the Potential Antiviral Activity of Mouthwash Reagent Chlorhexidine against SARS-CoV-2?

Chlorhexidine (CHX), a popular antibacterial drug, is widely used for oral health. Emerging pieces of evidence suggest that commercially available chlorhexidine mouthwash formulations are effective in suppressing the spread of SARS-CoV-2, possibly through destabilization of the viral lipid envelope. CHX is known for its membrane-active properties; however, the molecular mechanism revealing how it damages the viral lipid envelope is yet to be understood. Here we used extensive conventional and umbrella sampling simulations to quantify the effects of CHX on model membranes mimicking the composition of the SARS-CoV-2 outer lipid membrane as well as the host plasma membrane. Our results show that the lipid composition and physical properties of the membrane play an important role in binding and insertion, with CHX binding favorably to the viral membrane over the plasma membrane. Among the simulated lipids, CHX preferentially binds to anionic lipids, PS and PI, which are more concentrated in the viral membrane. The deeper and stable binding of CHX to the viral membrane results in more pronounced swelling of the membrane laterally with a thinning of the bilayer. The overall free energies of pore formation are strongly reduced for the viral membrane compared to the plasma membrane; however, CHX has a larger concentration-dependent effect on free energies of pore formation in the plasma membrane than the viral membrane. The results indicate that CHX is less toxic to the human plasma membrane at low concentrations. Our simulations reveal that CHX facilitates pore formation by the combination of thinning the membrane and accumulation at the water defect. This study provides insights into the mechanism underlying the anti-SARS-CoV-2 potency of CHX, supporting its potential for application as an effective and safe oral rinse agent for preventing viral transmission.

The effects of corticotomy and piezocision in orthodontic canine retraction: A randomized controlled clinical trial

Background:

There have been many studies and experiments to evaluate the effectiveness of different types of dental treatment. Maxillary canine extraction is such a dental treatment which can be performed through either alveolar corticotomy (AC) or piezocision (PZ). The current study aims to compare the effectiveness of these two types of dental procedures. It is based on a randomized clinical trial (RCT) through the split-mouth technique supported by a parallel group design. The participants in the trial were selected on the basis of a medical criterion. The clinical trial involved extraction of both the first maxillary premolar teeth through use of orthodontic instruments. This study aims to evaluate the comparative effectiveness of alveolar corticotomy and piezocision corticotomy in acceleration of maxillary canine retraction and how it can be used for expression of multiple bone remodeling gingival crevicular fluid (GCF). As part of this study, a RCT was performed on the basis of split-mouth technique at the Department of Orthodontics of Pontifical Catholic University at Minas Gerais in Brazil. The sample size for the clinical trial consisted of people who required extraction of maxillary premolar teeth after canine extraction. After digital intraoral scans, the cumulative distal movement of canines was measured on the basis of superimposition of digital model and the results were considered as the primary outcome of the study. The GCF bone remodeling samples were considered as the secondary outcomes.

Results:

50 patients, involving 22 males and 28 females were analyzed in this particular clinical trial. The age range that was considered for this clinical trial was 19–33 years. In case of understanding the distal movement between control and AC, no statistical significance was observed in Group1 (G1). Lower cumulative cervical and incisal measurements in case of PZ was lower than the measurement in the control state. In all the groups, the expression of the biomarkers had occurred in specific timepoints (P < 0.05) but no distinct pattern was observed.

Conclusions:

In order to accelerate the maxillary canine retraction, PZ and AC were ineffective. No distinct induction pattern of biomarker expression was noted as well.

Chlorhexidine mouthwash reduces the salivary viral load of SARS-CoV-2: A randomized clinical trial

OBJECTIVES

This study aimed to evaluate the effect of 0.12% chlorhexidine gluconate on the salivary load of SARS-CoV-2.

MATERIALS AND METHODS

A randomized, double-blind, placebo-controlled trial was performed on 100 participants positive for SARS-CoV-2. In the test group (n = 50), volunteers gargled with a mouthwash containing 15 ml of 0.12% chlorhexidine gluconate for 1 min, while the control group (n = 50) used a placebo. Saliva samples were obtained before (baseline) and 5 and 60 min after using the solutions. Real-time reverse transcription polymerase chain reaction assays (qRT-PCR) were carried out and the cycle threshold (Ct) was computed. The chi-square test and t-test were used for group comparison (p ≤ 0.05).

RESULTS

The differences in Ct values between the 5-min evaluation and baseline (test group: 2.19 ± 4.30; control: -0.40 ± 3.87, p = 0.002) and between 60 min and baseline (test group: 2.45 ± 3.88; control: 0.76 ± 4.41, p = 0.05) were significantly greater in the test group, revealing a reduction of viral load. Furthermore, there was a reduction in the load of SARS-CoV-2 in 72% of the volunteers using chlorhexidine versus 30% in the control group (p = 0.001).

CONCLUSIONS

Chlorhexidine gluconate (0.12%) was effective in reducing salivary SARS-CoV-2 load for at least 60 min.

Reduction of aerosols and splatter generated during ultrasonic scaling by adding food-grade thickeners to coolants: an in-vitro study

Objective

The effectiveness of using food-grade coolant thickener solutions on the amount of aerosols generated and splatter contamination spread distance during simulated ultrasonic scaling was examined.

Materials and methods

The study was performed using a phantom lower jaw placed on a black box. Simulated ultrasonic scaling was performed for 2 min using four coolant solutions: distilled water (control), 2% wt. polyacrylic acid (PAA), 0.4% wt. xanthan gum (XA), and 0.4% wt. carboxymethyl cellulose (CMC). The simulation was repeated 10 times for each coolant group. The generated aerosols and droplets were quantified using a handheld particle counter, and the splatter contamination spread distance was evaluated by adding tracing fluorescent dye to the coolant reservoir supplying the scaler unit. One-way multivariate analysis of variance was performed to determine the difference among coolant groups (a = .05).

Results

The amount of aerosols and droplets and splatter contamination distance (p < .001) pertaining to the three food-grade coolant thickener solutions were considerably lower than those for the distilled water (control). The PAA group exhibited a significantly lower splatter contamination distance (p < .001) and a number of generated droplets (p = .031) than those of the XA group. The CMC group exhibited a significantly lower splatter contamination distance (p < .001) than that of the XA group. No statistically significant difference was observed between the PAA and CMC in terms of the three dependent variables (p > .05).

Conclusion

The food-grade coolant thickeners could reduce the amount of generated aerosols and splatter contamination distance but not completely eliminate them. PAA and CMC solutions were more effective in reducing the aerosol/splatter during scaling compared to XA.

Clinical relevance

Many dental procedures generate aerosols and splatter, which pose a potential risk to the patients and dental personnel, especially during the current COVID-19 pandemic.

Virus transmission by ultrasonic scaler and its prevention by antiviral agent: an in vitro study

Background

It is well recognized that dental procedures represent a potential way of infection transmission. With the COVID‐19 pandemic, the focus of dental procedure associated transmission has rapidly changed from bacteria to viruses. The aim was to develop an experimental setup for testing the spread of viruses by ultrasonic scaler (USS) generated dental spray and evaluate its mitigation by antiviral coolants.

Methods

In a virus transmission tunnel, the dental spray was generated by USS with saline coolant and suspension of Equine Arteritis Virus (EAV) delivered to the USS tip. Virus transmission by settled droplets was evaluated with adherent RK13 cell lines culture monolayer. The suspended droplets were collected by a cyclone aero‐sampler. Antiviral activity of 0.25% NaOCl and electrolyzed oxidizing water (EOW) was tested using a suspension test. Antiviral agents' transmission prevention ability was evaluated by using them as a coolant.

Results

In the suspension test with 0.25% NaOCl or EOW, the TCID50/mL was below the detection limit after 5 seconds. With saline coolant, the EAV‐induced cytopathic effect on RK13 cells was found up to the distance of 45 cm, with the number of infected cells decreasing with distance. By aero‐sampler, viral particles were detected in concentration ≤4.2 TCID50/mL. With both antiviral agents used as coolants, no EAV‐associated RK‐13 cell infection was found.

Conclusion

We managed to predictably demonstrate EAV spread by droplets because of USS action. More importantly, we managed to mitigate the spread by a simple substitution of the USS coolant with NaOCl or EOW.

Virucidal efficacy of chlorhexidine: a systematic review

This study aimed to systematically review the literature about the virucidal efficacy of CHX in comparison to other substances used in the oral cavity. Electronic searches were performed in four databases (PubMed, Scopus, Embase, and Web of Science). Only studies that presented the following characteristics were included: (1) verified virucidal efficacy of CHX against Herpes Simplex Type-1 (HSV-1), any Influenza, or any human coronavirus (HcoV); and (2) compared the virucidal efficacy of CHX with essential oils (Listerine^®), quaternary ammonium compounds, povidone-iodine, hydrogen peroxide, negative control substance, and absence of therapy. Two researchers independently selected the studies, extracted data and evaluated the risk of bias. A narrative data synthesis was used. Twenty-five studies were included, of which 21 were in vitro and four were randomized clinical trials (RCT). Studies assessed the virucidal efficacy of CHX against Herpes Simplex Type-1 (HSV-1) (10 studies), Influenza A (InfluA) (4 studies), human coronavirus (HCoV) (4 studies) and Severe Acute Respiratory Syndrome-Related Coronavirus (SARS-CoV-2) (11 studies). Most studies demonstrated that CHX has a positive virucidal efficacy against HSV-1 and InfluA strains. However, lower efficacy was shown to InfluA strain in comparison to povidone-iodine. Lower to none virucidal efficacy of CHX is expected for HCoV and SARS-CoV-2 strains for in vitro studies. Three RCT demonstrated that CHX was able to significantly reduce the viral load of SARS-CoV-2 for a short period. CHX may present an interesting virucidal efficacy against HSV-1 and InfluA viruses. CHX also presents transient efficacy against SARS-CoV-2 when used as a mouthwash.

Educational concerns and awareness level among dental hygiene students during the COVID-19 pandemic

Objective

This study aimed to evaluate the educational concerns and awareness level among dental hygiene students during the COVID‐19 pandemic.

Materials and Methods

A questionnaire, created via Google Forms, was sent electronically to 240 dental hygiene students from Turkey, of which 223 replied to the survey. The questionnaire was divided into 4 parts and consisted of 24 close‐ended questions.

Results

The main symptoms of COVID‐19 were correctly recognized by 71% of the students, and 40.2% of the students were aware of the transmission routes. Of all, 77.1% of the students expressed fear of getting infected, 96.9% believed that they would more likely get infected while performing dental procedures, and 91% believed that dental hygienists’ cross‐contamination risk was high. Furthermore, 69.5% of the students stated that their undergraduate education process was negatively affected, 59.6% appreciated ongoing online education, and 31.8% wanted face‐to‐face clinical internships.

Conclusions

Although most of the students were aware of the transmission routes and preventive measures of COVID‐19, concerns regarding disease transmission among them remain. Students appreciated the ongoing online education and believed that face‐to‐face education is risky during this current pandemic. However, they believe that this process can adversely affect their professional knowledge and especially practical skills. A balance must be struck between sustaining an effective dental hygiene education process and containing the spread of COVID‐19.

Annual review of selected scientific literature: A report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry

The Scientific Investigation Committee of the American Academy of Restorative Dentistry offers this review of the 2020 professional literature in restorative dentistry to inform busy dentists regarding noteworthy scientific and clinical progress over the past year. Each member of the committee brings discipline-specific expertise to this work to cover this broad topic. Specific subject areas addressed include prosthodontics; periodontics, alveolar bone, and peri-implant tissues; implant dentistry; dental materials and therapeutics; occlusion and temporomandibular disorders (TMDs); sleep-related breathing disorders; oral medicine and oral and maxillofacial surgery; and dental caries and cariology. The authors focused their efforts on reporting information likely to influence day-to-day dental treatment decisions with a keen eye on future trends in the profession. With the tremendous volume of dentistry and related literature being published today, this review cannot possibly be comprehensive. The purpose is to update interested readers and provide important resource material for those interested in pursuing greater detail. It remains our intent to assist colleagues in navigating the extensive volume of important information being published annually. It is our hope that readers find this work useful in successfully managing the dental patients they encounter.

Aerosol generating procedural risks and concomitant mitigation strategies in orthodontics amid COVID-19 pandemic - An updated evidence-based review

IMPORTANCE

The ongoing COVID-19 pandemic has posed unique challenges to orthodontic profession by adversely impacting provision of in-office orthodontic care due to prevailing uncertainty around risks pertaining to splatter and 'aerosol-generating procedures' (AGPs). This review aims to provide an insight into the prevailing and emerging evidence informing potential risks related to splatter and AGPs, and risk mitigation strategies employed for reducing the potential risk of SARS-CoV-2 transmission from dental bioaerosols.

METHODS

PubMed, Google Scholar, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, LILACS, WHO COVID-19 databases and preprint databases were searched for eligible English language publications. Citation chasing was undertaken up until the review date of 4 January 2021. Study selection, data extraction and risk of bias assessment was undertaken independently in duplicate, or else by consultation with a third author.

RESULTS

Following filter application and duplicates removed, a total of 13 articles assessing procedural mitigation measures were included. Seven included studies revealed overall low-risk of bias. The overall risk varied from unclear to high for rest of the studies, with the most concerning domains being blinding of the participants and the personnel and blinding of the outcome assessors. Accumulated consensual evidence points towards the use of dental suction devices with wide bore aspirating tips as effective procedural mitigation strategies. Variations in the literature can be observed concerning aerosol transmission associated with water spray use during debonding. Emerging direct evidence consistently supports adjunctive use of pre-procedural povidone-iodine mouthrinse to mitigate direct transmission risk in the orthodontic practice.

CONCLUSIONS

A thorough risk assessment concerning AGPs and implementation of consistent and evidence-based procedural mitigation strategies may play an indispensable role in navigating optimal orthodontic practice through unforeseen similar pandemic threats. High-quality robust research focussing on more biologically relevant models of dental bioaerosols in orthodontic settings is warranted.

Size-resolved spatial distribution analysis of aerosols with or without the utilization of a novel aerosol containment device in dental settings

The coronavirus disease 2019 pandemic has imposed unprecedented occupational challenges for healthcare professionals. In dentistry, handheld instruments such as air and electric handpieces, ultrasonic scalers, and air/water syringes are capable of generating aerosols, droplets, and splatter, thereby exposing dental professionals to airborne contaminants such as viruses, bacteria, and fungi. The objective of the present study was to determine the spatial distribution of aerosols by size (0.30 to 20.00 μm) and the efficacy of a novel aerosol containment device (ACD) in a large operatory room with 12 dental chairs. Real-time portable laser aerosol spectrometers were used to measure the size-resolved number concentration of aerosols generated by a collision nebulizer. Results reported demonstrate that aerosol number concentrations significantly decreased as a function of distance with or without the utilization of the ACD. The ACD was able to efficiently decrease (up to 8.56-fold) the number and size distribution of particles in a large dental clinic. The novel device demonstrated higher efficiency for particles shown to contain the highest levels of severe acute respiratory syndrome coronavirus 2 in Chinese hospitals, thereby showing great promise to potentially decrease the spreading of nosocomial pathogens in dental settings.

The Impact of COVID-19 on Dental Research in Educational Settings: What are the Opportunities?

The COVID-19 pandemic has significantly impacted dental education and research activities, creating challenges for students, educators, and health-care professionals. The unfolding crisis has shed the light on how technology can facilitate not only the delivery of dental education and improving access to dental care but also new and ongoing research. While dental schools worldwide have re-structured their policies and curricula in terms of incorporating appropriate methods of distance learning, this now needs to be applied to dental research where appropriate. By conducting a "strengths, weaknesses, opportunities, and threats" analysis and describing the authors' experiences, here we discuss the impact of the pandemic on various aspects of dental research to provide a timely perspective on dental research activity in academic institutions to help achieve research outcomes despite the pandemic's impact.

Airborne particles and microorganisms in a dental clinic: Variability of indoor concentrations, impact of dental procedures, and personal exposure during everyday practice

This study presents for the first time comprehensive measurements of the particle number size distribution (10 nm to 10 μm) together with next-generation sequencing analysis of airborne bacteria inside a dental clinic. A substantial enrichment of the indoor environment with new particles in all size classes was identified by both activities to background and indoor/outdoor (I/O) ratios. Grinding and drilling were the principal dental activities to produce new particles in the air, closely followed by polishing. Illumina MiSeq sequencing of 16S rRNA of bioaerosol collected indoors revealed the presence of 86 bacterial genera, 26 of them previously characterized as potential human pathogens. Bacterial species richness and concentration determined both by qPCR, and culture-dependent analysis were significantly higher in the treatment room. Bacterial load of the treatment room impacted in the nearby waiting room where no dental procedures took place. I/O ratio of bacterial concentration in the treatment room followed the fluctuation of I/O ratio of airborne particles in the biology-relevant size classes of 1-2.5, 2.5-5, and 5-10 μm. Exposure analysis revealed increased inhaled number of particles and microorganisms during dental procedures. These findings provide a detailed insight on airborne particles of both biotic and abiotic origin in a dental clinic.

Salivary SARS-CoV-2 load reduction with mouthwash use: A randomized pilot clinical trial

The saliva of patients with COVID-19 has a high SARS-CoV-2 viral load. The risk of spreading the virus is high, and procedures for viral load reduction in the oral cavity are important. Little research to date has been performed on the effect of mouthwashes on the salivary SARS-CoV-2 viral load. This pilot randomized single-center clinical trial investigated whether three types of mouthwash with solutions containing either 0.075% cetylpyridinium chloride plus 0.28% zinc lactate (CPC + Zn), 1.5% hydrogen peroxide (HP), or 0.12% chlorhexidine gluconate (CHX) reduce the SARS-CoV-2 viral load in saliva at different time points. Sixty SARS-CoV-2-positive patients were recruited and randomly partitioned into a placebo (oral rinsing with distilled water) group and other groups according to the type of mouthwash. Saliva samples were collected from the participants before rinsing (T0), immediately after rinsing (T1), 30 min after rinsing (T2), and 60 min after rinsing (T3). The salivary SARS-CoV-2 viral load was measured by qRT-PCR assays. Rinsing with HP and CPC + Zn resulted in better reductions in viral load, with 15.8 ± 0.08- and 20.4 ± 3.7-fold reductions at T1, respectively. Although the CPC + Zn group maintained a 2.6 ± 0.1-fold reduction at T3, this trend was not observed for HP. HP mouthwash resulted in a significant reduction in the SARS-CoV-2 viral load up to 30 min after rinsing (6.5 ± 3.4). The CHX mouthwash significantly reduced the viral load at T1, T2, and T3 (2.1 ± 1.5-, 6.2 ± 3.8-, and 4.2 ± 2.4-fold reductions, respectively). In conclusion, mouthwash with CPC + Zinc and CHX resulted in significant reductions of the SARS-CoV-2 viral load in saliva up to 60 mins after rinsing, while HP mouthwash resulted in a significant reduction up to 30 mins after rinsing. Despite this transitory effect, these results encourage further studies and suggest that these products could be considered as risk-mitigation strategies for patients infected with SARS-CoV-2.

Effectiveness of Pre-procedural Mouth Rinses in Reducing Aerosol Contamination During Periodontal Prophylaxis: A Systematic Review

Background: Aerosol-producing dental procedures are of concern in the spread of infections, especially during the COVID-19 pandemic. Periodontal prophylaxis is the most common aerosol-producing procedure conducted in dental practice globally. During COVID-19, many national and international organizations advocated the use of pre-procedural mouth rinsing to prevent the spread of infections from aerosol-generating procedures in the dental setting; however, many questioned the scientific basis for such recommendations. Objective: This systematic review aimed to evaluate the effectiveness of pre-procedural rinsing when preforming periodontal prophylaxis in reducing aerosol contamination in the dental setting. Methods: A comprehensive standardized search strategy was employed, informed by a defined PICO question across four electronic databases. The review of the literature was conducted using the PRISMA framework. Agreement between assessors was determined throughout. Synthesis of study characteristics and key outcomes were conducted. Cochrane's risk-of-bias tool for randomized trials (RoB 2) was employed to assess the quality/bias among studies. Results: The initial search yielded 731 citations across the four databases; 95 potentially effective studies were identified, with 56 effective studies found. Thirty randomized control trial studies were identified, 21 with a focus on effectiveness of pre-procedural mouth rinsing, involving 984 participants (aged 18-70). Agreement between assessors was high (Kappa >0.80). Various pre-procedural mouth rinses were tested, most frequently chlorhexidine (CHX) in 18 studies. The concentrations, volume, and prescribed duration of rinsing varied among studies, hampering meta-analyses. Nonetheless, all studies identified significant reductions in bacterial contamination, as measured by colony forming units (cfu). The effectiveness of CHX over other agents was evident with more than half of the studies (7/15) reporting over a 70% reduction in bacterial contamination (cfu). There were concerns over the risk of bias in most studies (76.2%); 19.0% had a high risk of bias and 4.8% were of low risk of bias. Conclusion: There is substantial evidence to support pre-procedural mouth rinsing, such as with chlorohexidine, to effectively reduce aerosol contamination when performing periodontal prophylaxis compared to mouth rinsing with water or not rinsing.

Effect of work environment and specialty degree of dentists on cross-infection control in COVID-19 pandemic

Objectives

The aim of this study was to evaluate the effect of the work environment and expertise/specialty degree  of dentists on their behavior, awareness, and  attitudes regarding cross-infection control during the COVID-19 pandemic.

Design

The study population consisted of Turkish dentists who work in private clinics, public clinics and university hospitals. The demographic information of the participants, their awareness of the COVID-19 acute respiratory disease, and clinical measures taken against cross-infection were evaluated with an online survey. Between the 10^th and 20^th of November 2020, 2,400 surveys were e-mailed to dentists.

Results

A total 454 professionals answered the survey. According to the results, 29.3% of the participants performed only urgent care during the pandemic period, whereas 59.9% of them performed both urgent and routine treatments. Among the responding dentists, 90.6% stated that they were worried about aerosol-generating dental procedures, but there was no differences between genders (p = 0.119). Most participants, especially specialists (p = 0.160) , applied strict cross-infection control methods during the COVID-19  pandemic (77.2%). These dentists used personal protective equipment (PPE) at rates that varied between 75.5% and 98.4%. Nonetheless, the rate of PPE use was different between genders and degrees of expertise: women used PPE more frequently than men (p = 0.025), and specialists used PPE more often than the other dentists (p = 0.04). Finally, there was a weak positive correlation between the level of PPE use and expertise (r = 0.121; p = 0.010).

Conclusions

Despite the overall knowledge of the participants regarding COVID-19 symptoms, transmission routes, and the guidelines needed to prevent the virus from spreading, the dental specialists followed infection control methods more strictly. Even though the participants were concerned about dental practices that create microbial aerosols during the pandemic period, they continued their clinical routines using high PPE levels and taking extra clinical precautions to avoid cross-infection.

A bibliometric analysis of the dental scientific literature on COVID-19

Objectives

The rapid production of a large volume of literature during the early phase of the COVID-19 outbreak created a substantial burden for clinicians and scientists. Therefore, this manuscript aims to identify and describe the scientific literature addressing COVID-19 from a dental research perspective, in terms of the manuscript origin, research domain, study type, and level of evidence (LoE).

Materials and methods

Data were retrieved from Web of Science, Scopus, and PubMed. A descriptive analysis of bibliographic data, collaboration network, and keyword co-occurrence analysis were performed. Articles were further classified according to the field of interest, main research question, type of study, and LoE.

Results

The present study identified 296 dental scientific COVID-19 original papers, published in 89 journals, and co-authored by 1331 individuals affiliated with 429 institutions from 53 countries. Although 81.4% were single-country papers, extensive collaboration among the institutions of single countries (Italian, British, and Brazilian institutions) was observed. The main research areas were as follows: the potential use of saliva and other oral fluids as promising samples for COVID-19 testing, dental education, and guidelines for the prevention of COVID-19 transmission in dental practice. The majority of articles were narrative reviews, cross-sectional studies, and short communications. The overall LoE in the analyzed dental literature was low, with only two systematic reviews with the highest LoE I.

Conclusion

The dental literature on the COVID-19 pandemic does not provide data relevant to the evidence-based decision-making process. Future studies with a high LoE are essential to gain precise knowledge on COVID-19 infection within the various fields of Dentistry.

Clinical relevance

The published dental literature on COVID-19 consists principally of articles with a low level of scientific evidence which do not provide sufficient reliable high-quality evidence that is essential for decision making in clinical dental practice.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00784-021-03916-6.

Dentists' Working Conditions during the First COVID-19 Pandemic Lockdown: An Online Survey

The aim of this study was to investigate the operating conditions of dentists in Central Europe during the first coronavirus disease 2019 (COVID-19) lockdown. A survey including 24 questions was emailed to dentists in Austria, Germany, Switzerland and South Tyrol (Italy). Questions regarding dentists’ field of work, working hours, treatments performed, personal protective equipment and protocols, and economic consequences were asked. 1731 participants were included. 30.4% of participants worked mainly in Austria, 60.8% in Germany, 6% in Switzerland and 2.1% in South Tyrol. A country-specific analysis for the situation of South Tyrol was not possible due to the low participation; 53.7% of German, 45.5% of Austrian, and 11.7% of Swiss respondents reduced their working hours; 42.8% of Austrian, 41.5% of Swiss, and 17.3% of German participants closed their offices temporarily; 52.2% of respondents provided emergency service including pain management, restorations/temporaries, and denture repairs. A lack of access to FFP2/FFP3 (filtering facepiece) respirators was indicated by 59.4% Austrian, 38.0% German, and 11.7% Swiss dentists (p < 0.001). FFP2/FFP3 respirators were, when available, most frequently used in Austria (86.9%), followed by Switzerland (61.2%) and Germany (56.7%) (p < 0.001). Financial consequences could not be conclusively quantified by 58.6% of the participants. Most respondents in all partaking countries made use of governmental support. A lack of blueprints/guidelines resulted in heterogeneous working conditions. In consideration of a potentially high risk of infection in the dental setting, non-emergency dental treatments were largely suspended in all participating countries.

Impact of the COVID-19 pandemic on urgent dental care delivery in a Swiss university center for dental medicine

Objectives

This study aimed to assess whether the emergency service of a major Swiss dental institution faced different demands (patient volume, treatment needs, dental care characteristics) during a lockdown, issued to mitigate the COVID-19 pandemic, compared with the weeks before and after.

Materials and methods

Data of patients receiving urgent care at a university center for dental medicine (Basel, Switzerland) during the 6-week lockdown, pre-lockdown, and post-lockdown periods were retrospectively evaluated. Statistical analysis involved tests for equal proportions and logistic regression models. The level of significance was set at α=0.05.

Results

The study comprised 3109 dental emergency visits in the period from February 2 to June 5, 2020. Daily caseloads increased during lockdown. Abscesses, orthodontic emergencies, and surgical follow-ups were more common during lockdown, whereas the number of dento-alveolar injuries declined (≤0.048). Urgent dental care provision involved intraoral radiographs more frequently in the pre-lockdown period compared with the following weeks (p<0.001). Among all treatments, aerosol-generating procedures dropped from 56.1% (pre-lockdown) to 21.3% during lockdown (p<0.001), while teledentistry follow-ups became more frequent (p<0.001). Patients with comorbidities sought urgent dental care less frequently during the post-lockdown period (p=0.004).

Conclusions

The lockdown significantly impacted the dental emergency service in terms of patients’ diagnoses, treatment needs, and the characteristics of the urgent care that was delivered.

Clinical relevance

Access to essential dental care must be monitored and safeguarded throughout the COVID-19 pandemic and beyond as deferred care entails risks for serious sequelae and persons with comorbidities may change their dental care-seeking behavior.

Perioral Aerosol Sequestration Suction Device Effectively Reduces Biological Cross-Contamination in Dental Procedures

Objective  The infection risk during dental procedures is a common concern for dental professionals which has increased due to coronavirus (severe acute respiratory syndrome coronavirus 2) pandemic. The development of devices to specifically mitigate cross-contamination by droplet/splatter is crucial to stop infection transmission. The objective of this study is to assess the effectiveness of a perioral suction device (Oral BioFilter, OBF) to reduce biological contamination spread during dental procedures.

Materials and Methods  Forty patients were randomized 1:1 to a standard professional dental hygiene treatment with OBF and without. Adenosine triphosphate (ATP) bioluminescence assay was used to evaluate the spread of potential contaminants. The total number of relative light units (RLU) from key dental operatory locations: operator’s face-shield, back of the surgical operator’s-gloves, patient’s safety-goggles, and instrumental table were measured. Percentage contamination reductions between control and OBF were compared.

Statistical Analysis  Primary outcome, total RLU, was analyzed by comparing the means of logged data, using a two-sided two-sample t -test. Secondary outcomes as RLU of logged data for the different locations were analyzed in the same way. Proportion of patients from whom different locations reported events (clean, acceptable, and failure) were analyzed by using Fisher’s exact test.

Results  For the whole dental environment, RLUs reduction (<150 units) achieved with OBF was 98.4% (97.4–99%). By dental operatory location the reduction in RLUs was from 99.6%, on the operator face-shield, to 83% on instrumental table. The control group reported a very high percentage of failures, (>300) being 100% on the surfaces closer to the patient’s mouth and decreasing to 70% on instrumental table. In contrast, the higher failure percentage in the OBF group was found on the patient’s goggles (40%), while the operator face-shield showed an absence of contamination.

Conclusion  OBF device has shown efficient reduction of biological aerosol cross-contamination during dental procedures as proved by ATP-bioluminescence assay. Nevertheless, for maximum safety, its use must be combined with standard protective gear such as goggles, face shield, and surgical gloves.

Differential Effects of Antiseptic Mouth Rinses on SARS-CoV-2 Infectivity In Vitro

Severe acute respiratory syndrome-related coronavirus (SARS-CoV-2) is detectable in saliva from asymptomatic individuals, suggesting a potential benefit from the use of mouth rinses to suppress viral load and reduce virus spread. Published studies on the reduction of SARS-CoV-2-induced cytotoxic effects by mouth rinses do not exclude antiseptic mouth rinse-associated cytotoxicity. Here, we determined the effect of commercially available mouth rinses and antiseptic povidone-iodine on the infectivity of replication-competent SARS-CoV-2 viruses and of pseudotyped SARS-CoV-2 viruses. We first determined the effect of mouth rinses on cell viability to ensure that antiviral activity was not a consequence of mouth rinse-induced cytotoxicity. Colgate Peroxyl (hydrogen peroxide) exhibited the most cytotoxicity, followed by povidone-iodine, chlorhexidine gluconate (CHG), and Listerine (essential oils and alcohol). The potent antiviral activities of Colgate Peroxyl mouth rinse and povidone-iodine were the consequence of rinse-mediated cellular damage when the products were present during infection. The potency of CHG was greater when the product was not washed off after virus attachment, suggesting that the prolonged effect of mouth rinses on cells impacts the antiviral outcome. To minimalize mouth rinse-associated cytotoxicity, mouth rinse was largely removed from treated viruses by centrifugation prior to infection of cells. A 5% (v/v) dilution of Colgate Peroxyl or povidone-iodine completely blocked viral infectivity. A similar 5% (v/v) dilution of Listerine or CHG had a moderate suppressive effect on the virus, but a 50% (v/v) dilution of Listerine or CHG blocked viral infectivity completely. Mouth rinses inactivated the virus without prolonged incubation. The new infectivity assay, with limited impacts of mouth rinse-associated cytotoxicity, showed the differential effects of mouth rinses on SARS-CoV-2 infection. Our results indicate that mouth rinses can significantly reduce virus infectivity, suggesting a potential benefit for reducing SARS-CoV-2 spread.

Methods to mitigate infection spread from aerosol-generating dental procedures

Infection control measures play a critical role in preventing the spread of disease in healthcare settings. Concerns that SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2), the virus that causes Coronavirus Disease 2019, may be transmitted through droplets and aerosols from both symptomatic and asymptomatic individuals has turned the spotlight on healthcare interventions that involve aerosol generation in the oral cavity, such as many dental and periodontal procedures. This commentary seeks to familiarize the dental practitioner with various infection control methods that may be implemented to mitigate spread of infection in dental settings through aerosol-generating dental procedures.

Effects of mechanical ventilation and portable air cleaner on aerosol removal from dental treatment rooms

Objectives

To evaluate the mechanical ventilation rates of dental treatment rooms and assess the effectiveness of aerosol removal by mechanical ventilation and a portable air cleaner (PAC) with a high-efficiency particulate air (HEPA) filter.

Methods

Volumetric airflow were measured to assess air change rate per hour by ventilation (ACH_vent). Equivalent ventilation provided by the PAC (ACH_pac) was calculated based on its clean air delivery rate. Concentrations of 0.3, 0.5 and 1.0 μm aerosol particles were measured in 10 dental treatment rooms with various ventilation rates at baseline, after 5-min of incense burn, and after 30-min of observation with and without the PAC or ventilation system in operation. Velocities of aerosol removal were assessed by concentration decay constants for the 0.3 μm particles with ventilation alone (K_n) and with ventilation and PAC (K_n+pac), and by times needed to reach 95 % and 100 % removal of accumulated aerosol particles.

Results

ACH_vent varied from 3 to 45. K_n and K_n+pac were correlated with ACH_vent (r = 0.90) and combined ACH_total (r = 0.81), respectively. Accumulated aerosol particles could not be removed by ventilation alone within 30-min in rooms with ACH_vent<15. PAC reduced aerosol accumulation and accelerated aerosol removal, and accumulated aerosols could be completely removed in 4 to 12-min by ventilation combined with PAC. Effectiveness of the PAC was especially prominent in rooms with poor ventilation. Added benefit of PAC in aerosol removal was inversely correlated with ACH_vent.

Conclusions

Aerosol accumulation may occur in dental treatment rooms with poor ventilation. Addition of PAC with a HEPA filter significantly reduced aerosol accumulation and accelerated aerosol removal.

Clinical significance

Addition of PAC with a HEPA filter improves aerosol removal in rooms with low ventilation rates.

Differential effects of antiseptic mouth rinses on SARS-CoV-2 infectivity in vitro

SARS-CoV-2 is detectable in saliva from asymptomatic individuals, suggesting a potential benefit from the use of mouth rinses to suppress viral load and reduce virus spread. Published studies on reduction of SARS-CoV-2-induced cytotoxic effects by antiseptics do not exclude antiseptic-associated cytotoxicity. Here, we determined the effect of commercially available mouth rinses and antiseptic povidone-iodine on the infectivity of SARS-CoV-2 virus and of a non-pathogenic, recombinant, SARS-CoV-2 infection vector (pseudotyped SARS-CoV-2 virus). We first determined the effect of mouth rinses on cell viability to ensure that antiviral activity was not a consequence of mouth rinse-induced cytotoxicity. Colgate Peroxyl (hydrogen peroxide) exhibited the most cytotoxicity, followed by povidone-iodine, chlorhexidine gluconate (CHG), and Listerine (essential oils and alcohol). Potent anti-viral activities of povidone iodine and Colgate peroxyl mouth rinses was the consequence of rinse-mediated cellular damage. The potency of CHG was greater when the product was not washed off after virus attachment, suggesting that the prolonged effect of mouth rinses on cells impacts anti-viral activity. To minimalize mouth rinse-associated cytotoxicity, mouth rinse was largely removed from treated-viruses by centrifugation prior to infection of cells. A 5% (v/v) dilution of Colgate Peroxyl or povidone-iodine completely blocked viral infectivity. A similar 5% (v/v) dilution of Listerine or CHG had a moderate suppressive effect on the virus, but a 50% (v/v) dilution of Listerine or CHG blocked viral infectivity completely. Prolonged incubation of virus with mouth rinses was not required for viral inactivation. Our results indicate that mouth rinses can significantly reduce virus infectivity, suggesting a potential benefit for reducing SARS-CoV-2 spread.

COVID-19: What do we know?

•Evidence regarding the provision of orthodontic care during the COVID-19 pandemic is examined.

Interventions to reduce contaminated aerosols produced during dental procedures for preventing infectious diseases

BACKGROUND

Many dental procedures produce aerosols (droplets, droplet nuclei and splatter) that harbour various pathogenic micro-organisms and may pose a risk for the spread of infections between dentist and patient. The COVID-19 pandemic has led to greater concern about this risk.

OBJECTIVES

To assess the effectiveness of methods used during dental treatment procedures to minimize aerosol production and reduce or neutralize contamination in aerosols.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched the following databases on 17 September 2020: Cochrane Oral Health's Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) (in the Cochrane Library, 2020, Issue 8), MEDLINE Ovid (from 1946); Embase Ovid (from 1980); the WHO COVID-19 Global literature on coronavirus disease; the US National Institutes of Health Trials Registry (ClinicalTrials.gov); and the Cochrane COVID-19 Study Register. We placed no restrictions on the language or date of publication.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) and controlled clinical trials (CCTs) on aerosol-generating procedures (AGPs) performed by dental healthcare providers that evaluated methods to reduce contaminated aerosols in dental clinics (excluding preprocedural mouthrinses). The primary outcomes were incidence of infection in dental staff or patients, and reduction in volume and level of contaminated aerosols in the operative environment. The secondary outcomes were cost, accessibility and feasibility.

DATA COLLECTION AND ANALYSIS

Two review authors screened search results, extracted data from the included studies, assessed the risk of bias in the studies, and judged the certainty of the available evidence. We used mean differences (MDs) and 95% confidence intervals (CIs) as the effect estimate for continuous outcomes, and random-effects meta-analysis to combine data. We assessed heterogeneity.

MAIN RESULTS

We included 16 studies with 425 participants aged 5 to 69 years. Eight studies had high risk of bias; eight had unclear risk of bias. No studies measured infection. All studies measured bacterial contamination using the surrogate outcome of colony-forming units (CFU). Two studies measured contamination per volume of air sampled at different distances from the patient's mouth, and 14 studies sampled particles on agar plates at specific distances from the patient's mouth. The results presented below should be interpreted with caution as the evidence is very low certainty due to heterogeneity, risk of bias, small sample sizes and wide confidence intervals. Moreover, we do not know the 'minimal clinically important difference' in CFU. High-volume evacuator Use of a high-volume evacuator (HVE) may reduce bacterial contamination in aerosols less than one foot (~ 30 cm) from a patient's mouth (MD -47.41, 95% CI -92.76 to -2.06; 3 RCTs, 122 participants (two studies had split-mouth design); very high heterogeneity I² = 95%), but not at longer distances (MD -1.00, -2.56 to 0.56; 1 RCT, 80 participants). One split-mouth RCT (six participants) found that HVE may not be more effective than conventional dental suction (saliva ejector or low-volume evacuator) at 40 cm (MD CFU -2.30, 95% CI -5.32 to 0.72) or 150 cm (MD -2.20, 95% CI -14.01 to 9.61). Dental isolation combination system One RCT (50 participants) found that there may be no difference in CFU between a combination system (Isolite) and a saliva ejector (low-volume evacuator) during AGPs (MD -0.31, 95% CI -0.82 to 0.20) or after AGPs (MD -0.35, -0.99 to 0.29). However, an 'n of 1' design study showed that the combination system may reduce CFU compared with rubber dam plus HVE (MD -125.20, 95% CI -174.02 to -76.38) or HVE (MD -109.30, 95% CI -153.01 to -65.59). Rubber dam One split-mouth RCT (10 participants) receiving dental treatment, found that there may be a reduction in CFU with rubber dam at one-metre (MD -16.20, 95% CI -19.36 to -13.04) and two-metre distance (MD -11.70, 95% CI -15.82 to -7.58). One RCT of 47 dental students found use of rubber dam may make no difference in CFU at the forehead (MD 0.98, 95% CI -0.73 to 2.70) and occipital region of the operator (MD 0.77, 95% CI -0.46 to 2.00). One split-mouth RCT (21 participants) found that rubber dam plus HVE may reduce CFU more than cotton roll plus HVE on the patient's chest (MD -251.00, 95% CI -267.95 to -234.05) and dental unit light (MD -12.70, 95% CI -12.85 to -12.55). Air cleaning systems One split-mouth CCT (two participants) used a local stand-alone air cleaning system (ACS), which may reduce aerosol contamination during cavity preparation (MD -66.70 CFU, 95% CI -120.15 to -13.25 per cubic metre) or ultrasonic scaling (MD -32.40, 95% CI - 51.55 to -13.25). Another CCT (50 participants) found that laminar flow in the dental clinic combined with a HEPA filter may reduce contamination approximately 76 cm from the floor (MD -483.56 CFU, 95% CI -550.02 to -417.10 per cubic feet per minute per patient) and 20 cm to 30 cm from the patient's mouth (MD -319.14 CFU, 95% CI - 385.60 to -252.68). Disinfectants ‒ antimicrobial coolants Two RCTs evaluated use of antimicrobial coolants during ultrasonic scaling. Compared with distilled water, coolant containing chlorhexidine (CHX), cinnamon extract coolant or povidone iodine may reduce CFU: CHX (MD -124.00, 95% CI -135.78 to -112.22; 20 participants), povidone iodine (MD -656.45, 95% CI -672.74 to -640.16; 40 participants), cinnamon (MD -644.55, 95% CI -668.70 to -620.40; 40 participants). CHX coolant may reduce CFU more than povidone iodine (MD -59.30, 95% CI -64.16 to -54.44; 20 participants), but not more than cinnamon extract (MD -11.90, 95% CI -35.88 to 12.08; 40 participants).

AUTHORS' CONCLUSIONS

We found no studies that evaluated disease transmission via aerosols in a dental setting; and no evidence about viral contamination in aerosols. All of the included studies measured bacterial contamination using colony-forming units. There appeared to be some benefit from the interventions evaluated but the available evidence is very low certainty so we are unable to draw reliable conclusions. We did not find any studies on methods such as ventilation, ionization, ozonisation, UV light and fogging. Studies are needed that measure contamination in aerosols, size distribution of aerosols and infection transmission risk for respiratory diseases such as COVID-19 in dental patients and staff.

Rubber Dam Isolation and High-Volume Suction Reduce Ultrafine Dental Aerosol Particles: An Experiment in a Simulated Patient

The ongoing Coronavirus Disease 2019 (COVID-19) pandemic has triggered the paralysis of dental services ascribed to the potential spread of severe acute respiratory syndrome (SARS)-CoV-2. Aerosol-generating procedures (AGPs) are common in dentistry, which in turn increase the risk of infection of the dental personnel due to the salivary presence of SARS-CoV-2 in COVID-19 patients. The use of rubber dam isolation (RDI) and high-volume evacuators (HVE) during AGPs is recommended to control dental aerosols, but the evidence about their effectiveness is scarce. This first study aimed to compare, in a simulated patient, the effectiveness of the following strategies: standard suction (SS), RDI and RDI + HVE. Using the laser diffraction technique, the effect of each condition on the volume distribution, average size and concentration of coarse (PM10), fine (PM2.5) and ultrafine (PM0.1) particles were evaluated. During the teeth drilling, the highest volume fraction of dental aerosol particles with SS was below 1 μm of aerodynamic diameter. Additionally, the RDI + HVE significantly reduced both the ultrafine dental aerosol particles and the concentration of total particulate matter. AGPs represent a potential risk for airborne infections in dentistry. Taken together, these preliminary results suggest that isolation and high-volume suction are effective to reduce ultrafine dental aerosol particles.

Minimizing the aerosol-generating procedures in orthodontics in the era of a pandemic: Current evidence on the reduction of hazardous effects for the treatment team and patients

The purpose of this critical review is to list the sources of aerosol production during orthodontic standard procedure, analyze the constituent components of aerosol and their dependency on modes of grinding, the presence of water and type of bur, and suggest a method to minimize the quantity and detrimental characteristics of the particles comprising the solid matter of aerosol. Minimization of water-spray syringe utilization for rinsing is suggested on bonding related procedures, while temporal conditions as represented by seasonal epidemics should be considered for the decision of intervention scheme provided as a preprocedural mouth rinse, in an attempt to reduce the load of aerosolized pathogens. In normal conditions, chlorhexidine 0.2%, preferably under elevated temperature state should be prioritized for reducing bacterial counts. In the presence of oxidation vulnerable viruses within the community, substitute strategies might be represented by the use of povidone iodine 0.2%-1%, or hydrogen peroxide 1%. After debonding, extensive material grinding, as well as aligner related attachment clean-up, should involve the use of carbide tungsten burs under water cooling conditions for cutting efficiency enhancement, duration restriction of the procedure, as well as reduction of aerosolized nanoparticles. In this respect, selection strategies of malocclusions eligible for aligner treatment should be reconsidered and future perspectives may entail careful and more restricted utilization of attachment grips. For more limited clean-up procedures, such as grinding of minimal amounts of adhesive remnants, or individualized bracket debonding in the course of treatment, hand-instruments for remnant removal might well represent an effective strategy. Efforts to minimize the use of rotary instrumentation in orthodontic settings might also lead the way for future solutions. Measures of self-protection for the treatment team should never be neglected. Dressing gowns and facemasks with filter protection layers, appropriate ventilation and fresh air flow within the operating room comprise significant links to the overall picture of practice management. Risk management considerations should be constant, but also updated as new material applications come into play, while being grounded on the best available evidence.

Innovative diagnostic approach and investigation trends in COVID19-A systematic review

A highly contagious viral infection emerged in Wuhan city; China had increased mortality with uncertain pathogenesis spreads throughout the world to become a pandemic. It is reported to be caused by a member of β coronaviruses and named it as COVID-19 by the World Health Organization (WHO). The disease is caused by a mutant strain of coronavirus SARS-COV-2 that affects the respiratory tract causing mild to severe respiratory tract illness. The clinical manifestation ranges from mild, moderate, severe and very severe signs and symptoms result in death due to severe hypoxia or multi-organ dysfunction. Also, the affected persons were capable of infecting others through various modes of transmission through respiratory droplets (aerosol spread). A definite investigation protocol has followed to diagnose COVID 19 disease but mainly confirmed with reverse transcription polymerase chain reaction. Computerized tomography scan plays a significant role in the diagnosis and prognosis of affected individuals. The major problem with COVID-19 is due to its novelty and lack of vaccination or treatment. This review focuses on the mutation, pathogenesis, various diagnostic tests adopted and autopsy findings in patients affected with COVID-19.