Potential Role of Oral Rinses Targeting the Viral Lipid Envelope in SARS-CoV-2 Infection

Mouthwashes with CPC Reduce the Infectivity of SARS-CoV-2 Variants In Vitro

Oral mouthwashes decrease the infectivity of several respiratory viruses including SARS-CoV-2. However, the precise agents with antiviral activity in these oral rinses and their exact mechanism of action remain unknown. Here we show that cetylpyridinium chloride (CPC), a quaternary ammonium compound in many oral mouthwashes, reduces SARS-CoV-2 infectivity by inhibiting the viral fusion step with target cells after disrupting the integrity of the viral envelope. We also found that CPC-containing mouth rinses decreased more than a thousand times the infectivity of SARS-CoV-2 in vitro, while the corresponding vehicles had no effect. This activity was effective for different SARS-CoV-2 variants, including the B.1.1.7 or Alpha variant originally identified in United Kingdom, and in the presence of sterilized saliva. CPC-containing mouth rinses could therefore represent a cost-effective measure to reduce SARS-CoV-2 infectivity in saliva, aiding to reduce viral transmission from infected individuals regardless of the variants they are infected with.

Surfactants - Compounds for inactivation of SARS-CoV-2 and other enveloped viruses

We provide here a general view on the interactions of surfactants with viruses, with a particular emphasis on how such interactions can be controlled and employed for inhibiting the infectivity of enveloped viruses, including coronaviruses. The aim is to provide to interested scientists from different fields, including chemistry, physics, biochemistry, and medicine, an overview of the basic properties of surfactants and (corona)viruses, which are relevant to understanding the interactions between the two. Various types of interactions between surfactant and virus are important, and they act on different components of a virus such as the lipid envelope, membrane (envelope) proteins and nucleocapsid proteins. Accordingly, this cannot be a detailed account of all relevant aspects but instead a summary that bridges between the different disciplines. We describe concepts and cover a selection of the relevant literature as an incentive for diving deeper into the relevant material. Our focus is on more recent developments around the COVID-19 pandemic caused by SARS-CoV-2, applications of surfactants against the virus, and on the potential future use of surfactants for pandemic relief. We also cover the most important aspects of the historical development of using surfactants in combatting virus infections. We conclude that surfactants are already playing very important roles in various directions of defence against viruses, either directly, as in disinfection, or as carrier components of drug delivery systems for prophylaxis or treatment. By designing tailor-made surfactants, and consequently, advanced formulations, one can expect more and more effective use of surfactants, either directly as antiviral compounds or as part of more complex formulations.

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.

Use of an antiviral mouthwash as a barrier measure in the SARS-CoV-2 transmission in adults with asymptomatic to mild COVID-19: a multicentre, randomized, double-blind controlled trial

Objectives

To determine if commercially available mouthwash with β-cyclodextrin and citrox (bioflavonoids) (CDCM) could decrease the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) salivary viral load.

Methods

In this randomized controlled trial, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) PCR-positive patients aged 18–85 years with asymptomatic to mild coronavirus disease 2019 (COVID-19) symptoms for <8 days were recruited. A total of 176 eligible patients were randomly assigned (1:1) to CDCM or placebo. Three rinses daily were performed for 7 days. Saliva sampling was performed on day 1 at 09.00 (T1), 13.00 (T2) and 18.00 (T3). On the following 6 days, one sample was taken at 15.00. Quantitative RT-PCR was used to detect SARS-CoV-2.

Results

The intention-to-treat analysis demonstrated that, over the course of 1 day, CDCM was significantly more effective than placebo 4 hours after the first dose (p 0.036), with a median percentage (log₁₀ copies/mL) decrease T1–T2 of –12.58% (IQR –29.55% to –0.16%). The second dose maintained the low median value for the CDCM (3.08 log₁₀ copies/mL; IQR 0–4.19), compared with placebo (3.31 log₁₀ copies/mL; IQR 1.18–4.75). At day 7, there was still a greater median percentage (log₁₀ copies/mL) decrease in salivary viral load over time in the CDCM group (–58.62%; IQR –100% to –34.36%) compared with the placebo group (–50.62%; IQR –100% to –27.66%). These results were confirmed by the per-protocol analysis.

Conclusions

This trial supports the relevance of using CDCM on day 1 (4 hours after the initial dose) to reduce the SARS-CoV-2 viral load in saliva. For long-term effect (7 days), CDMC appears to provide a modest benefit compared with placebo in reducing viral load in saliva.

Cyclodextrins in the antiviral therapy

The main antiviral drug-cyclodextrin interactions, changes in physicochemical and physiological properties of the most commonly used virucides are summarized. The potential complexation of antiviral molecules against the SARS-Cov2 also pointed out the lack of detailed information in designing effective and general medicines against viral infections. The principal problem of the current molecules is the 3D structures of the currently active compounds. Improving the solubility or bioavailability of antiviral molecules is possible, however, there is no universal solution, and the complexation experiments dominantly use the already approved cyclodextrin derivatives. This review discusses the basic properties of the different cyclodextrin derivatives, their potential in antiviral formulations, and the prevention and treatment of viral infections. The biologically active new cyclodextrin derivatives are also discussed.

Impact of COVID-19 on Dentistry

The coronavirus disease 2019 (COVID-19) pandemic has affected the health-care system drastically, including dental care practice. COVID-19, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is thought to spread via close contact through respiratory droplets and aerosols. Owing to specific characteristics of dental care such as aerosol generation as well as close proximity to patients, dentistry is thought to be associated with the nosocomial spread of infection. The risk of bidirectional spread of infection between patient and dental care providers makes it critical to take additional precautionary measures to mitigate the spread of COVID-19. It is essential to understand that the guidelines for providing dental treatment during the COVID-19 pandemic will vary across the globe, and dental practices should be in compliance with their regional guidelines. This chapter aims to present an overview of the dynamics of COVID-19 transmission and its impact on dentistry and discuss measures to provide dental care during the time of the COVID-19 outbreak effectively.

Effectiveness of hydrogen peroxide as auxiliary treatment for hospitalized COVID-19 patients in Brazil: preliminary results of a randomized double-blind clinical trial

OBJECTIVES

To evaluate the effectiveness of hydrogen peroxide (H2O2) in the form of mouthwash and nasal spray as an auxiliary treatment for coronavirus disease 2019 (COVID-19).

METHODS

Forty hospitalized patients who tested positive for severe acute respiratory syndrome coronavirus 2 using a reverse-transcription polymerase chain reaction test were evaluated. They were randomly divided into an experimental group (n= 20; gargling with 1.0% H2O2 and nasal wash with 0.5% H2O2) or a control group (n= 20). The solutions were used for 7 days and the patients were monitored every 2 days, for a total of 8 days. At check-ups, patients were asked about their symptoms and possible adverse effects of the solutions. The presence and severity (mild, moderate, or severe) of symptoms were recorded. Data were compared using the Student test and the Fisher exact test (α= 0.05).

RESULTS

There was no significant difference between the 2 groups in the length of hospital stay (p= 0.65). The most frequent symptom on day 0 was coughing (72.0% in the experimental group and 76.5% in the control group), which abated over time. There was no significant difference between the groups in the evaluated symptoms. Most (75.0%) of the patients in the experimental group presented a reduction in dyspnea between days 0 and 2. Few patients reported adverse effects from the use of the solutions.

CONCLUSIONS

H2O2 as a mouthwash and nasal spray is safe to use. There is insufficient evidence to demonstrate that H2O2 is effective as an auxiliary treatment for hospitalized COVID-19 patients.

Can povidone iodine gargle/mouthrinse inactivate SARS-CoV-2 and decrease the risk of nosocomial and community transmission during the COVID-19 pandemic? An evidence-based update

The Coronavirus disease in 2019 (COVID-19), also referred to as the novel ‘CoV19 (nCov19)’ is caused by a new coronavirus strain similar to Severe Acute Respiratory Syndrome (SARS-CoV-2). SARS-CoV-2 spreads via respiratory droplets, saliva, or direct contact. Therefore it is important to control the viral load in the saliva and respiratory secretions. One of the most simple and cost-effective measures that can be adopted by the public and healthcare professionals to prevent cross-contamination and community transmission, is the implementation of effective oral and throat hygiene. Recent evidence has confirmed that 0.5% povidone iodine (PVP-I) mouthrinse/gargle for 30 s can reduce SARS-CoV-2 virus infectivity to below detectable levels. PVP-I can even interrupt SARS-CoV-2 attachment to oral and nasopharyngeal tissues and lower the viral particles in the saliva and respiratory droplets. Thus, the use of PVP-I mouthrinse as a prophylactic measure has been advocated across the globe to reduce disease transmission. Although the efficacy of PVP-I against SARS-CoV-2 is proven, no review articles have yet discussed the evidence and mechanisms of PVP-I against the SARS-CoV-2. Thus, this paper highlights the rationale, safety, recommendations, and dosage of PVP-I gargle/mouthrinse as an effective method to decrease the viral loads during the pressing times of COVID-19.

Efficacy of Mouth Rinses Against SARS-CoV-2: A Scoping Review

Introduction:The presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in saliva and nasopharyngeal secretions has challenged the routine practice of dentistry. Use of preprocedural mouth rinses has been recommended by several organizations to potentially reduce the transmission of SARS-CoV-2. This scoping review aimed at evaluating the available evidence on the efficacy of mouth rinses against SARS-CoV-2.

Methods:A thorough literature search on electronic databases (PubMed, Scopus, and Google Scholar) was performed by two independent reviewers and data from articles addressing the aim of this article were extracted.

Results:After exclusion of articles not addressing the end point in question, 12 articles were included in this scoping review. Of the 12 articles, seven werein vitrostudies and five werein vivohuman clinical studies. Thein vitrostudies used a standardized methodology (endpoint dilution assay) to evaluate the efficacy of antimicrobial mouth rinses against SARS-CoV-2. Thein vivostudies were done utilizing polymerase chain reaction assay of samples obtained from saliva or nasopharyngeal swab or a combination of both nasopharyngeal and oropharyngeal swab. The reagents tested in these studies included povidone-iodine, chlorhexidine, hydrogen peroxide (H2O2), essential oils, and quaternary ammonium compounds and demonstrated varied efficacy against SARS-CoV-2.

Conclusion:Based on the available evidence fromin vitrostudies, it can be concluded that mouth rinses have a potential to reduce SARS-CoV-2 viral load; however, effectiveness inin vivoconditions is still inconclusive. Owing to the substantial heterogeneity in reporting of the anti–SARS-CoV-2 efficacy of mouth rinses, this review highlights the need to conduct future research with robust and standardized methodologies to confirm effectiveness of mouth rinses.

Inactivation of SARS-CoV-2 through Treatment with the Mouth Rinsing Solutions ViruProX® and BacterX® Pro

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic effects daily dental work. Therefore, infection control measures are necessary to prevent infection of dental personnel during dental treatments. The use of a preprocedural mouth rinse with chlorhexidine (CHX), cetylpyridinium chloride (CPC), or hydrogen peroxide (H₂O₂) solution for 30–60 s may reduce the viral load and may protect the personnel in a dental practice. In the present study the virucidal effect of the mouth rinsing solutions ViruProX^® with 0.05% CPC and 1.5% H₂O₂ and BacterX^® pro containing 0.1% CHX, 0.05% CPC, and 0.005% sodium fluoride (F^-) was investigated in vitro. The mouth rinsing solutions successfully inactivated infectious SARS-CoV-2 particles, the causative agent of coronavirus disease 2019 (COVID-19), within 30 s. To determine the effective components, CHX, CPC, H₂O₂, and a combination of CHX and CPC, were tested against SARS-CoV-2 in addition. While a combination of CPC and CHX as well as CPC alone led to a significant reduction of infectious viral particles, H₂O₂ and CHX alone had no virucidal effect against SARS-CoV-2. It can be assumed that preprocedural rinsing of the mouth with ViruProX^® or BacterX^® pro will reduce the viral load in the oral cavity and could thus lower the transmission of SARS-CoV-2 in dental practice.

COVID-19 salivary Raman fingerprint: innovative approach for the detection of current and past SARS-CoV-2 infections

The pandemic of COVID-19 is continuously spreading, becoming a worldwide emergency. Early and fast identification of subjects with a current or past infection must be achieved to slow down the epidemiological widening. Here we report a Raman-based approach for the analysis of saliva, able to significantly discriminate the signal of patients with a current infection by COVID-19 from healthy subjects and/or subjects with a past infection. Our results demonstrated the differences in saliva biochemical composition of the three experimental groups, with modifications grouped in specific attributable spectral regions. The Raman-based classification model was able to discriminate the signal collected from COVID-19 patients with accuracy, precision, sensitivity and specificity of more than 95%. In order to translate this discrimination from the signal-level to the patient-level, we developed a Deep Learning model obtaining accuracy in the range 89-92%. These findings have implications for the creation of a potential Raman-based diagnostic tool, using saliva as minimal invasive and highly informative biofluid, demonstrating the efficacy of the classification model.

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.

Dental Practitioners' Knowledge, Attitude and Practices for Mouthwash Use Amidst the COVID-19 Pandemic

Introduction

COVID-19 created a peculiar situation worldwide, thus altering the fundamental dynamics of clinical dentistry. This KAP survey was carried out to evaluate the knowledge, attitude and practices among dental practitioners regarding the use of mouthwashes and emphasize on pre-procedural utilization of mouthwashes.

Methodology

A descriptive, cross-sectional study was conducted during 1st to 15th July 2020, among working dental practitioners across the globe. A questionnaire was formed on Kwiksurveys.com, it comprised of demographic details, it further investigated the level of knowledge and new precautionary measures adopted. A total number of 707 dental practitioners from eighteen different countries responded.

Results

Data were analyzed using SPSS version 23. A "fisher exact test" was applied to assess the difference between the mouthwashes prescribed by various countries. Knowledge section revealed a requisite understanding regarding the disease and its transmission. Only 38.9% of the participants knew that Povidone-iodine (PVP-I) mouthwashes are more efficient in reducing coronaviruses in contrast to mouthwashes made of chlorhexidine (CHX). Whereas 33.9% knew that 0.23% of PVP-I had substantial virucidal activity against SARS-COV, MERS-CoV, influenza virus and rotavirus while 31.1% recognized that oral rinses of Cetylpyridinium chloride (CPC) remained successful in the oral cavity for up to 180-300 minutes.

Conclusion

There is an immense need to raise awareness among practitioners, regarding the viricidal activity of commercially available mouthwashes as demonstrated by numerous in-vitro studies and urge health workers to carry out more clinical trials and to get a translational step towards clinical practice.

Antiviral Activity of Reagents in Mouth Rinses against SARS-CoV-2

The oral cavity, an essential part of the upper aerodigestive tract, is believed to play an important role in the pathogenicity and transmission of SARS-CoV-2. The identification of targeted antiviral mouth rinses to reduce salivary viral load would contribute to reducing the COVID-19 pandemic. While awaiting the results of significant clinical studies, which to date do not exist, the commercial availability of mouth rinses leads us to search among them for reagents that would have specific antiviral properties with respect to SARS-CoV-2. The challenges facing this target were examined for 7 reagents found in commercially available mouth rinses and listed on the ClinicalTrials.gov website: povidone-iodine, chlorhexidine, hydrogen peroxide, cyclodextrin, Citrox, cetylpyridinium chloride, and essential oils. Because SARS-CoV-2 is an enveloped virus, many reagents target the outer lipid membrane. Moreover, some of them can act on the capsid by denaturing proteins. Until now, there has been no scientific evidence to recommend mouth rinses with an anti-SARS-CoV-2 effect to control the viral load in the oral cavity. This critical review indicates that current knowledge of these reagents would likely improve trends in salivary viral load status. This finding is a strong sign to encourage clinical research for which quality protocols are already available in the literature.

Can preprocedural mouthrinses reduce SARS-CoV-2 load in dental aerosols?

Dental professionals work closely with patients and present an increased risk of person-to-person transmission of SARS-CoV-2. Moreover, the use of ultrasonic scalers, air-water syringes, and slow and high-speed handpieces, which are common in the dental office, generate spatter and aerosol. The use of preprocedural mouthrinses has been proposed to reduce the viral load in saliva and oropharyngeal tissues, thus decreasing viral load in dental aerosol. Although some mouthrinses demonstrates an antiviral effect, there is limited evidence about the clinical efficacy of any mouthrinse in the reduction of SARS-CoV-2 in the dental aerosol. We hypothesized that mouthrinses may reduce SARS-CoV-2 viral load in the oropharynx and its fluids reducing viral load in dental aerosol. The potential use of mouthrinses is discussed, along with proposal of in vitro and clinical studies, in order to evaluate this hypothesis. If this hypothesis holds true, dental professionals and patients may benefit from the routine use of preprocedural mouthrinses.

Efficacy of commercial mouth-rinses on SARS-CoV-2 viral load in saliva: randomized control trial in Singapore

Purpose

One of the key approaches to minimize the risk of COVID-19 transmission would be to reduce the titres of SARS-CoV-2 in the saliva of infected COVID-19 patients. This is particularly important in high-risk procedures like dental treatment. The present randomized control trial evaluated the efficacy of three commercial mouth-rinse viz. povidone–iodine (PI), chlorhexidine gluconate (CHX) and cetylpyridinium chloride (CPC), in reducing the salivary SARS-CoV-2 viral load in COVID-19 patients compared with water.

Methods

A total of 36 SARS-CoV-2-positive patients were recruited, of which 16 patients were randomly assigned to four groups—PI group (n = 4), CHX group (n = 6), CPC group (n = 4) and water as control group (n = 2). Saliva samples were collected from all patients at baseline and at 5 min, 3 h and 6 h post-application of mouth-rinses/water. The samples were subjected to SARS-CoV-2 RT-PCR analysis.

Results

Comparison of salivary Ct values of patients within each group of PI, CHX, CPC and water at 5 min, 3 h and 6 h time points did not show any significant differences. However, when the Ct value fold change of each of the mouth-rinse group patients were compared with the fold change of water group patients at the respective time points, a significant increase was observed in the CPC group patients at 5 min and 6 h and in the PI group patients at 6 h.

Conclusion

The effect of decreasing salivary load with CPC and PI mouth-rinsing was observed to be sustained at 6 h time point. Within the limitation of the current study, as number of the samples analyzed, the use of CPC and PI formulated that commercial mouth-rinses may be useful as a pre-procedural rinse to help reduce the transmission of COVID-19.

ISRCTN (ISRCTN95933274), 09/09/20, retrospectively registered

In vitro virucidal activity of povidone iodine gargle and mouthwash against SARS-CoV-2: implications for dental practice

Introduction Virus particles in respiratory droplets and aerosols generated during medical/dental procedures are a potential source of SARS-CoV-2 cross infection. In the dental setting, oral decontamination could be an important adjunct to personal protective equipment and is recommended by a number of national COVID-19 guidance documents for dental settings.Aim To assess the in vitrovirucidal activity of an oral povidone iodine (PVP-I) product against SARS-CoV-2.Material and methods BETADINE gargle and mouthwash (1% PVP-I) was tested against SARS-CoV-2 virus under both clean and dirty conditions using a suspension assay based on EN14476 methodology. Virucidal activity of the product, undiluted and at 1:2 dilution, was tested at contact times of 15, 30 and 60 seconds. Viral titres were calculated using the Spearman-Kärber method and reported as median tissue culture infectious dose (TCID50/ml).Results The undiluted product achieved >5 log10 reduction in viral titres compared to the control at 15, 30 and 60 seconds under both clean and dirty conditions. At a twofold dilution (0.5% PVP-I), the test product demonstrated >4 log10 kill at 15 seconds and >5 log10 kill at 30 and 60 seconds in both clean and dirty conditions.Conclusion PVP-I gargle and mouthwash product, undiluted and at 1:2 dilution, demonstrated potent and rapid virucidal activity (≥4 log10 reduction of viral titre) in 15 seconds against SARS-CoV-2 in vitro. The PVP-I gargle and mouthwash product is widely available and could be readily integrated into infection control measures during dental treatment including pre-procedural oral decontamination.

A Pan-Canadian narrative review on the protocols for reopening dental services during the COVID-19 pandemic

The current coronavirus disease 2019 (COVID-19) pandemic is impacting the way in which dental services are provided. The aim of this narrative review was twofold: to summarize key areas from the Canadian protocols available for the reopening and restructuring of dental services across the country and to critically review these protocols based on existing evidence. A narrative review of the existing Canadian protocols, written in English and French, was undertaken between April 15 and July 13, 2020. The protocols were obtained by searching through regulatory bodies and websites from professional organizations, and from personal contacts through academic institutions and policy leaders. The data extraction form focused only on protocols related to dentistry, and the information was compiled by a hired assistant. Content was categorized via group discussions with the research team on eight areas: office management and procedures, patient and staff screening, treatment procedures, office layout, risk reduction, personal protective equipment, supporting information, and length and readability. Thirteen protocols were identified and offered substantial variation in the level of details provided. All but two protocols specified proper donning/doffing of personal protective equipment, while all protocols recommended daily monitoring of COVID-19 related signs and symptoms in staff and patients. They varied in terms of recommended mask types, eye and face shield protection, and head coverings. While all protocols aimed at restructuring emergency dental services, their recommendations were often not based on the published evidence. This narrative review summarized key areas from 13 provincial and territorial protocols in Canada to help oral health care providers plan the reopening of their services. The information conveyed across all documents was clear, but variance highlights the need for a coordinated effort to develop an evidence-based document for dental practitioners.

Current uses of chlorhexidine for management of oral disease: a narrative review

OBJECTIVES

Chlorhexidine (CHX) is a commonly used antiseptic mouthwash, used by dental practitioners and the public, due to its antimicrobial effects. The aim of this article was to provide a narrative review of current antimicrobial uses of CHX relevant to dentistry in the context of oral diseases, highlighting need for further studies to support its safe and appropriate use.

STUDY SELECTION, DATA AND SOURCES

Randomised controlled trials, systematic reviews and national (UK and US) guidelines were consulted where available, with search terms for each subject category entered into MEDLINE, PubMed, Google Scholar and the Cochrane database.

RESULTS

Some evidence existed to support adjunctive short-term use of CHX to manage dental plaque, and reduce clinical symptoms of gingivitis, dry socket, as well as reduce aerosolisation of bacteria. However, use must be weighed alongside the less desirable effects of CHX, including extrinsic staining of teeth, antimicrobial resistance to antiseptic agents and the rare, but fatal, allergic reactions to CHX. Conversely, evidence for the effectiveness of chlorhexidine to manage or prevent periodontitis, dental caries, necrotising periodontal diseases, peri-implantitis, and infections associated with extraction and aerosolised viruses remains less certain.

CONCLUSIONS

The use of CHX in dentistry and oral healthcare continues to be widespread and thus it is important that dental practitioners understand that, based on its differential mechanisms of action on different microbes, appropriate clinical and dental use of CHX should be oral disease specific. However, further scientific and clinical research is required before full recommendations can be made.

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 and Oral Surgery: A narrative review of preoperative mouth rinses

OBJECTIVE

To provide a narrative review of the preprocedural mouth rinse protocols suggested for oral surgery in order to contrast the presence of SARS-CoV-2 in aerosol.

SOURCES AND METHODS

Electronic searches were performed in medical databases PubMed, Medline, CINAHN and Scopus to identify relevant studies published up until the third week of April 2020. This research was supplemented by exploration through a web-based search engine as well as a manual search for international and national guidelines. Studies and protocols which suggested preoperative mouth rinsing as a recommended measure during the COVID-19 outbreak were included. Given the small number of studies, a narrative literature review was conducted. In total, 15 references (11 articles and 4 guidelines) were considered relevant and were critically analysed.

CONCLUSION

The findings show a high heterogeneity in the protocols suggested. Further research is required to better understand the viral features and epidemiologic characteristics of this new virus and to test the efficacy of commonly used antiseptics against SARS-CoV-2 in future clinical trials. However, the use of chlorhexidine, hydrogen peroxide, PVP-I and cetylpyridinium chloride in contrasting the spread of Covid-19 is described as advisable and substantial in different publications.

COVID-19: Topical agents and therapeutic prevention of nasal viral acquisition

Since the spread of SARS-CoV-2 became a pandemic, the number of cases has been continuously growing worldwide. Numerous recommendations and suggestions have been published to prevent the acquisition and spread of the SARS-CoV-2, especially to protect health workers and front-line caregivers. SARS-CoV-2 is transmitted by aerosol, rendering air defense with suitable ventilation and adequate mask use pivotal. Recently, locally applied antiseptic, antiviral, or structure competitive receptor blockers were suggested to attack the virus at its main point of invasion, the nasal mucosa and nasopharynx. We discuss the most plausible and safe ideas to reduce viral load at the point of entry, and subsequently the spread of SARS-CoV-2 to the lower respiratory tract, lungs, and other organs. In addition, we analyze the value and recommend clinical trials employing topical trichloroacetic acid (TCA), a substance well known from dermatologic and cosmetic procedures. It has been proven to successfully block the nasal entry for airborne allergens, preventing the development of allergic rhinitis and asthma, and to be curative for early stages of viral infections entering through the oral mucosa. For SARS-CoV-2, TCA in a single, short-time application is expected to remodel the nasal and nasopharyngeal epithelia, eliminating both the receptors and cells responsible for viral entry and subsequent viral spread to the lower respiratory tract. Moreover, this may have therapeutic benefits for those recently infected by reducing local viral replication. Such procedures are cheap, safe, and can be conducted in almost every setting, especially in regions with inadequate financial and logistic resources.

COVID-19: What do we know?

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

A Pathophysiological Model for COVID-19: Critical Importance of Transepithelial Sodium Transport upon Airway Infection

The Coronavirus Disease 2019 (COVID-19) pandemic remains a serious public health problem and will continue to be until effective drugs and/or vaccines are available. The rational development of drugs critically depends on our understanding of disease mechanisms, that is, the physiology and pathophysiology underlying the function of the organ targeted by the virus. Since the beginning of the pandemic, tireless efforts around the globe have led to numerous publications on the virus, its receptor, its entry into the cell, its cytopathic effects, and how it triggers innate and native immunity but the role of apical sodium transport mediated by the epithelial sodium channel (ENaC) during the early phases of the infection in the airways has received little attention. We propose a pathophysiological model that defines the possible role of ENaC in this process.

Virucidal Efficacy of Different Oral Rinses Against Severe Acute Respiratory Syndrome Coronavirus 2

The ongoing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic creates a significant threat to global health. Recent studies suggested the significance of throat and salivary glands as major sites of virus replication and transmission during early coronavirus disease 2019, thus advocating application of oral antiseptics. However, the antiviral efficacy of oral rinsing solutions against SARS-CoV-2 has not been examined. Here, we evaluated the virucidal activity of different available oral rinses against SARS-CoV-2 under conditions mimicking nasopharyngeal secretions. Several formulations with significant SARS-CoV-2 inactivating properties in vitro support the idea that oral rinsing might reduce the viral load of saliva and could thus lower the transmission of SARS-CoV-2.

Combating SARS-CoV-2: leveraging microbicidal experiences with other emerging/re-emerging viruses

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Wuhan City, China, late in December 2019 is an example of an emerging zoonotic virus that threatens public health and international travel and commerce. When such a virus emerges, there is often insufficient specific information available on mechanisms of virus dissemination from animal-to-human or from person-to-person, on the level or route of infection transmissibility or of viral release in body secretions/excretions, and on the survival of virus in aerosols or on surfaces. The effectiveness of available virucidal agents and hygiene practices as interventions for disrupting the spread of infection and the associated diseases may not be clear for the emerging virus. In the present review, we suggest that approaches for infection prevention and control (IPAC) for SARS-CoV-2 and future emerging/re-emerging viruses can be invoked based on pre-existing data on microbicidal and hygiene effectiveness for related and unrelated enveloped viruses.

Povidone-Iodine Demonstrates Rapid In Vitro Virucidal Activity Against SARS-CoV-2, The Virus Causing COVID-19 Disease

INTRODUCTION

As of 22 June 2020, Severe Acute Respiratory Syndrome (SARS)-coronavirus (CoV)-2 has infected more than 8.95 million people worldwide, causing > 468,000 deaths. The virus is transmitted through respiratory droplets and physical contact from contaminated surfaces to the mucosa. Hand hygiene and oral decontamination among other measures are key to preventing the spread of the virus. We report the in vitro virucidal activity of topical and oral povidone-iodine (PVP-I) products against SARS-CoV-2.

METHODS

Suspension assays were used to assess the virucidal activity of PVP-I against SARS-CoV-2. Products were tested at a contact time of 30 s for virucidal activity. Viral titres were calculated using the Spearman-Kärber method and reported as median tissue culture infectious dose (TCID50)/mL.

RESULTS

All four products [antiseptic solution (PVP-I 10%), skin cleanser (PVP-I 7.5%), gargle and mouth wash (PVP-I 1%) and throat spray (PVP-I 0.45%)] achieved ≥ 99.99% virucidal activity against SARS-CoV-2, corresponding to ≥ 4 log10 reduction of virus titre, within 30 s of contact.

CONCLUSION

This study provides evidence of rapid and effective virucidal activity of PVP-I against SARS-CoV-2. PVP-I-based products are widely available for medical and personal use for hand hygiene and oral decontamination, and could be readily integrated into coronavirus disease, COVID-19, infection control measures in hospital and community settings.

The Effects of Chloroquine and Hydroxychloroquine on ACE2-Related Coronavirus Pathology and the Cardiovascular System: An Evidence-Based Review

The ongoing pandemic of coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) poses a serious threat to global public health and there is currently no effective antiviral therapy. It has been suggested that chloroquine (CQ) and hydroxychloroquine (HCQ), which were primarily employed as prophylaxis and treatment for malaria, could be used to treat COVID-19. CQ and HCQ may be potential inhibitors of SARS-CoV-2 entry into host cells, which are mediated via the angiotensin-converting enzyme 2 (ACE2), and may also inhibit subsequent intracellular processes which lead to COVID-19, including damage to the cardiovascular (CV) system. However, paradoxically, CQ and HCQ have also been reported to cause damage to the CV system. In this review, we provide a critical examination of the published evidence. CQ and HCQ could potentially be useful drugs in the treatment of COVID-19 and other ACE2 involved virus infections, but the antiviral effects of CQ and HCQ need to be tested in more well-designed clinical randomized studies and their actions on the CV system need to be further elucidated. However, even if it were to turn out that CQ and HCQ are not useful drugs in practice, further studies of their mechanism of action could be helpful in improving our understanding of COVID-19 pathology.

Comparison of In Vitro Inactivation of SARS CoV-2 with Hydrogen Peroxide and Povidone-Iodine Oral Antiseptic Rinses

Purpose

To evaluate the in vitro inactivation of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) with hydrogen peroxide (H₂O₂) and povidone‐iodine (PVP‐I) oral antiseptic rinses at clinically recommended concentrations and contact times.

Materials and Methods

SARS‐CoV‐2, USA‐WA1/2020 strain virus stock was prepared prior to testing by growing in Vero 76 cells. The culture media for prepared virus stock was minimum essential medium (MEM) with 2% fetal bovine serum (FBS) and 50 µg/mL gentamicin. Test compounds consisting of PVP‐I oral rinse solutions and H₂O₂ aqueous solutions were mixed directly with the virus solution so that the final concentration was 50% of the test compound and 50% of the virus solution. Thus PVP‐I was tested at concentrations of 0.5%, 1.25%, and 1.5%, and H₂O₂ was tested at 3% and 1.5% concentrations to represent clinically recommended concentrations. Ethanol and water were evaluated in parallel as standard positive and negative controls. All samples were tested at contact periods of 15 seconds and 30 seconds. Surviving virus from each sample was then quantified by standard end‐point dilution assay and the log reduction value of each compound compared to the negative control was calculated.

Results

After the 15‐second and 30‐second contact times, PVP‐I oral antiseptic rinse at all 3 concentrations of 0.5%, 1.25%, and 1.5% completely inactivated SARS‐CoV‐2. The H₂O₂ solutions at concentrations of 1.5% and 3.0% showed minimal viricidal activity after 15 seconds and 30 seconds of contact time.

Conclusions

SARS‐CoV‐2 virus was completely inactivated by PVP‐I oral antiseptic rinse in vitro, at the lowest concentration of 0.5 % and at the lowest contact time of 15 seconds. Hydrogen peroxide at the recommended oral rinse concentrations of 1.5% and 3.0% was minimally effective as a viricidal agent after contact times as long as 30 seconds. Therefore, preprocedural rinsing with diluted PVP‐I in the range of 0.5% to 1.5% may be preferred over hydrogen peroxide during the COVID‐19 pandemic.