The role of the oral cavity in SARS-CoV-2- and other viral infections.

OBJECTIVE: This study aims to review the role of the oral cavity in SARS-CoV-2- and other viral upper respiratory tract infections. MATERIAL AND METHODS: Data reviewed in the text have been researched online and also reflect personal expertise. RESULTS: Numerous respiratory and other viruses replicate in the oral cavity and are transmitted via aerosols (< 5 µm) and droplets (> 5 µm). SARS-CoV-2 replication has been documented in the upper airways as well as in oral mucosa and salivary glands. These sites are also virus reservoirs that can infect other organs, e.g., the lungs and gastrointestinal tract, as well as other individuals. Laboratory diagnosis of viruses in the oral cavity and upper airways focuses on real-time PCR; antigen tests are less sensitive. For screening and monitoring infections, nasopharyngeal and oral swabs are tested; saliva is a good and more comfortable alternative. Physical means like social distancing or masks have been proven successful to reduce the risk of infection. Both wet-lab and clinical studies confirm that mouth rinses are effective against SARS-CoV-2 and other viruses. Antiviral mouth rinses can inactivate all viruses that replicate in the oral cavity. CONCLUSIONS: The oral cavity plays an important role in viral infections of the upper respiratory tract: it serves as a portal of entry, a site of replication, and a source of infection by droplets and aerosols. Physical means but also antiviral mouth rinses can help reduce the spread of viruses and contribute to infection control.

Development of a novel, entirely herbal-based mouthwash effective against common oral bacteria and SARS-CoV-2.

BACKGROUND: Parallel to the growth of the oral healthcare market, there is a constantly increasing demand for natural products as well. Many customers prefer products that contain fewer toxic agents, therefore providing an environmentally friendly solution with the benefit of smaller risk to the user. Medieval and early modern medicinal knowledge might be useful when looking for natural, herbal-based components to develop modern products. Along with these considerations we created, tested, and compared an entirely natural mouthwash, named Herba Dei. METHODS: The manufacturing procedure was standardized, and the created tincture was evaluated by GC/MS analysis for active compounds, experimentally tested in cell-based cytotoxicity, salivary protein integrity, cell-free antioxidant activity, anti-bacterial and anti-viral assays, and compared with three market-leading mouthwashes. RESULTS: Our tincture did not show significant damage in the cytotoxicity assays to keratinocyte and Vero E6 cells and did not disrupt the low molecular weight salivary proteins. Its radical scavenging capacity surpassed that of two tested, partly natural, and synthetic mouthwashes, while its antibacterial activity was comparable to the tested products, or higher in the bacterial aerobic respiratory assay. The active compounds responsible for the effects include naturally occurring phenylpropanoids, terpenes, and terpenoids. Our mouthwash proved to be effective in vitro in lowering the copy number of SARS-CoV-2 in circumstances mimicking the salivary environment. CONCLUSIONS: The developed product might be a useful tool to impede the transmission and spread of SARS-CoV-2 in interpersonal contact and aerosol-generating conditions. Our mouthwash can help reduce the oral bacterial flora and has an antioxidant activity that facilitates wound healing and prevents adverse effects of smoke in the oral cavity.

Efficacy of mouthrinses in reducing oral SARS-COV-2 load: a review.

Accumulated evidence has shown that the oral cavity may be an important reservoir for SARS-CoV-2. Some authors have suggested that the use of mouthrinses could reduce SARS-CoV-2 viral load in the saliva. Thus, the aim of this review was to synthesize evidence about the efficacy of mouthrinses in reducing the salivary viral load of SARS-CoV-2. 2. Nine randomized controlled trials (RCTs) have investigated the efficacy of different mouthrinses in reducing salivary SARS-CoV-2 loads. Various active ingredients have been tested in these trials: 0.5%,1% and 2% povidone-iodine, 0.2% and 0.12% chlorhexidine (CHX), 0.075% cetylpyridinium chloride (CPC), 0.075% CPC with Zinc lactate, 1% and 1.5% hydrogen peroxide (HP), 1.5% HP + 0.12% CHX and ß-cyclodextrin and citrox. The studies reported an intra-group reduction in the salivary levels of the virus, when compared with the baseline. However, the majority of these trials failed to demonstrate a significant inter-group difference between active groups and the control group relative to the decrease in salivary SARS-CoV-2 loads. Although promising, these results should be confirmed by larger trials.

Oral Microbiome, Mental Health, and Sleep Outcomes During the COVID-19 Pandemic: An Observational Study in Chinese and Korean American Immigrants.

COVID-19 is a systemic disease whose effects are not limited to the respiratory system. The oral microbiome (OM)-brain axis is of growing interest in understanding the broader, neuropsychiatric, impacts of the COVID-19 pandemic through a systems biology lens. In this context, mental health and sleep disturbance are often reported by Asian Americans. In a cross-sectional observational study design, we examined the associations of the oral microbiome with mental health among Asian Americans during the COVID-19 pandemic (between November 2020 and April 2021). Participants (n = 20) were adult Chinese and Korean American immigrants in Atlanta, Georgia, and primarily born outside the United States (60%) with a mean age of 34.8 years ±14 (standard deviation). Participants reported depressive symptoms, anxiety, and sleep disturbance, as measured by standard questionnaires. The OM was characterized by 16S rRNA V3-V4 gene using saliva. Depressive symptoms and anxiety were reported by 60% (n = 12) of participants, whereas 35% (n = 7) reported sleep disturbance. The α-diversity was significantly associated with depressive symptoms, and marginally with anxiety. Participants with depressive symptoms and anxiety had enriched Rothia and Scardovia, respectively, whereas those without symptoms had enriched Fusobacterium. Individuals with sleep disturbance had enriched Kingella. In conclusion, this study suggests significant associations of the OM diversity with certain mental health dimensions such as depressive symptoms and anxiety. Specific taxa were associated with these symptoms. The present observations in a modest sample size suggest the possible relevance of the OM-brain axis in studies of mental health during COVID-19.

Head and neck cancer recurrence with limited mouth opening, radiation fibrosis and confirmed COVID-19 infection: Approach to airway management.

We present a case that describes the airway management of a patient with recurrent head and neck cancer and confirmed COVID-19 infection. Securing airway of these patients with anticipated difficulty and at the same time limiting virus exposure to providers can be challenging. The risk of aerosolization during awake tracheal intubation is extreme as it carries a high risk of transmitting respiratory infections. A multidisciplinary team discussion before the procedure highlighted aspects of both airway management and the urgency of surgical procedure where particular care and modifications are required. Successful flexible bronchoscopy and intubation was done under inhalational anaesthetics with spontaneous breathing. Although fiberoptic intubation during sleep,in anticipated difficult airways, have led to enhanced intubation time, this technique was opted to minimize the risk of aerosol generation associated with topicalisation, coughing and hence reduced incidence of cross infection to health care workers.

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).

Oral Health Implications of SARS-CoV-2/COVID-19: A Systematic Review.

PURPOSES: The aim of this sytematic review was to evaluate the potential association of COVID-19 infection with oral health. MATERIALS AND METHODS: Screening in different databases (PubMed/MEDLINE, Google Scholar, and Embase databases) was performed to identify relevant articles, focusing on the oral health of patients with COVID-19, and published up to November 2021. 5194 articles were identified, and 29 fulfilled the inclusion criteria. RESULTS: Patients presenting more severe periodontal or dental diseases were at an increased risk of developing COVID-19 complications and being admitted to intensive care units. According to the included articles, U-shaped lingual papillitis and aphthous-like ulcers on the tongue are the most frequent lesions assessed in the oral cavity of COVID-19 patients, while xerostomia seems to be an early COVID-19 diagnostic symptom. Apart from the presence of the virus, the global lockdown had a detrimental impact on oral health. The occurrence of dental emergencies was augmented during this time due to the postponement of numerous non-emergency dental procedures. CONCLUSIONS: The presence of SARS-CoV-2 in periodontal tissues and salivary fractions may explain the presence of oral lesions during the infection. However, the virus's direct or indirect effect on oral mucosa is unclear. It is important to consider that these manifestations might be attributed to underlying comorbidities, or co-existing or subsequent lesions produced by local irritants.

The Role of the Plasminogen/Plasmin System in Inflammation of the Oral Cavity.

The oral cavity is a unique environment that consists of teeth surrounded by periodontal tissues, oral mucosae with minor salivary glands, and terminal parts of major salivary glands that open into the oral cavity. The cavity is constantly exposed to viral and microbial pathogens. Recent studies indicate that components of the plasminogen (Plg)/plasmin (Pm) system are expressed in tissues of the oral cavity, such as the salivary gland, and contribute to microbial infection and inflammation, such as periodontitis. The Plg/Pm system fulfills two major functions: (a) the destruction of fibrin deposits in the bloodstream or damaged tissues, a process called fibrinolysis, and (b) non-fibrinolytic actions that include the proteolytic modulation of proteins. One can observe both functions during inflammation. The virus that causes the coronavirus disease 2019 (COVID-19) exploits the fibrinolytic and non-fibrinolytic functions of the Plg/Pm system in the oral cavity. During COVID-19, well-established coagulopathy with the development of microthrombi requires constant activation of the fibrinolytic function. Furthermore, viral entry is modulated by receptors such as TMPRSS2, which is necessary in the oral cavity, leading to a derailed immune response that peaks in cytokine storm syndrome. This paper outlines the significance of the Plg/Pm system for infectious and inflammatory diseases that start in the oral cavity.

Large erupted complex odontoma mimicking maxillary osteomyelitis.

Odontoma is the most common benign odontogenic hamartoma. Odontomas are of two types, such as viz compound and complex odontoma. The complex type is a conglomeration of hard tissues of dental origin. They are primarily intraosseous and usually present in the second decade of life. Most odontomas are asymptomatic, but those erupting in the oral cavity may cause severe infection. They are often associated with impacted teeth and are present with the anterior maxilla showing the highest propensity.The present case report is of a male patient in his early 60s with a substantial solitary sclerotic odontoma of the middle and posterior segments of the maxilla erupted into the oral cavity communicating with the right maxillary sinus. The delayed presentation, size, location and active suppuration can misguide clinicians.

A comparative study of positive and negative electronic word-of-mouth on the SERVQUAL scale during the COVID-19 epidemic - taking a regional teaching hospital in Taiwan as an example.

BACKGROUND: In recent years, studies have shown that electronic WOM (eWOM) directly reflects consumers' post-purchase psychological perception and directly affects repurchase behavior. This information is valued by institutions in various fields. Within the scope of the evaluation of service characteristics, medical service is the least visible and most difficult service attribute to evaluate. Service organizations must have high trust attributes. Therefore, an eWOM review significantly influences people's decision-making process when choosing a healthcare provider. The purpose of this research is to combine eWOM reviews with the SERVQUAL scale in a comparative study of positive and negative eWOM reviews of a regional teaching hospital in Taiwan. METHODS: This research obtained data from publicly available eWOM reviews on Google Maps of a regional teaching hospital in Taiwan over the past 10 years (from June 24, 2011, to December 31, 2021) using website scraping technology. The semantic content analysis method was used in this study to classify eWOM reviews according to the revised PZB SERVQUAL scale. RESULTS: Statistical analysis was conducted. During the COVID-19 pandemic, positive reviews showed a downward trend. Among the five determinants of the SERVQUAL of PZB, positive eWOM reviews performed best in "assurance" with a positive review rate of 60.00%, followed by 42.11% for "reliability". For negative eWOM reviews, "assurance" performed the worst with a positive rate of 72.34%, followed by "responsiveness" at 28.37% and "reliability" at 26.95%. CONCLUSION: Since the onset of COVID-19 in 2020, negative eWOM has increased significantly and exceeded the amount of positive eWOM. Regardless of positive and negative reviews, what patients care most about is "assurance" of the professional attitude and skills of medical staff, which urgently needs to be strengthened. In addition, good "reliability" will help to develop positive eWOM. However, "responsiveness" as indicated by poor service waiting time can easily lead to the spread of negative eWOM. Hospital management should focus on these service-oriented qualities.

Long-Term Post-COVID-19 Associated Oral Inflammatory Sequelae.

The oral cavity remains an underappreciated site for SARS-CoV-2 infection despite the myriad oral conditions observed in COVID-19 patients. Recently, replicating SARS-CoV-2 was found inside salivary epithelial cells resulting in inflammation and atrophy of salivary glands. Saliva possesses healing properties crucial for maintaining the health of the oral mucosa. Specifically, salivary antimicrobial peptides, most notable, histatin-5 exclusively produced in salivary glands, plays a vital role in innate immunity against colonizing microbial species. The demonstration of SARS-CoV-2 destruction of gland tissue where histatin-5 is produced strongly indicate that histatin-5 production is compromised due to COVID-19. Here we present a case of a patient presenting with unexplained chronic oral dysesthesia and dysgeusia post-recovery from COVID-19. To explore potential physiological mechanisms behind the symptoms, we comparatively analyzed saliva samples from the patient and matched healthy subject for histatin-5 and key cytokines. Findings demonstrated significantly reduced histatin-5 levels in patient's saliva and activation of the Th17 inflammatory pathway. As histatin-5 exhibits potent activity against the opportunistic oral pathogen Candida albicans, we evaluated saliva potency against C. albicans ex vivo. Compared to control, patient saliva exhibited significantly reduced anti-candidal efficacy. Although speculative, based on history and salivary analysis we hypothesize that salivary histatin-5 production may be compromised due to SARS-CoV-2 mediated salivary gland destruction. With the current lack of emphasis on implications of COVID-19 on oral health, this report may provide lacking mechanistic insights that may lead to reassessment of risks for oral opportunistic infections and mucosal inflammatory processes in acutely-ill and recovered COVID-19 patients.

Determination of Internal Temperature by Measuring the Temperature of the Body Surface Due to Environmental Physical Factors-First Study of Fever Screening in the COVID Pandemic.

The SARS-CoV-2 virus pandemic has shown that the use of a contact thermometer to verify the elevated body temperature of a suspected person carries a risk of spreading disease. The perfect solution seems to be the use of thermal imaging as a diagnostic method in fever evaluation. The aim of the research is to develop an algorithm for thermovision measurements in fever screening standards in the context of the impact of various weather conditions on the temperature of people entering the public institution. Each examined person had two thermal images of the face-AP and lateral projection. Using a T1020 FLIR thermal camera with a resolution of 1024 × 768 pixels; the mean temperature was measured from the area of the forehead, the maximum forehead, the corners of the eyes, the inside of the mouth and the external auditory canal temperature. On the other hand, using classic contact thermometers, the temperature in the armpit and ear was measured. The obtained preliminary results showed very strong and positive correlations between the temperature in the ear measured with an ear thermometer and the maximum, minimum and average forehead temperature. These correlations oscillate at approximately r = 0.6, but the highest value of Spearman coefficient was obtained for the mean temperature of the forehead. Moreover, high correlations were also obtained between the temperature in the ear, measured with an ear thermometer, and the maximum temperature in the corners of the eyes and in the ear, measured with a thermal imaging camera. These values were, respectively, r = 0.54, r = 0.65. In summarizing, remote body temperature measurement taken with a thermal camera can be useful in the assessment of the body's core temperature.

Syzygium aromaticum as a bactericidal candidate: effects on the oral microbiota / Syzygium aromaticum como candidato a bactericida: efectos en la microbiota oral

El cavo de olor (Syzygium aromaticum) es un árbol, originario de Indonesia, con altura variable, pero que sobre pasa los 10 metros de altura, perteneciente a la familia de las Myrtaceae y cuyas flores que no han abierto, se convierten en botones, que al secar son los mencionados clavos de olor. Poseen como componente principal el Eugenol, entre otros compuestos orgánicos. Por sus características bioquímicas y organolépticas, le proporcionan varios beneficios para la salud, por actuar como estimulantes, antioxidante, con acción antibacterial, antiespasmódicas, además de su marcada acción analgésica y anestésica. Por su parte, la microbiota oral, está conformada por un amplio conjunto de microorganismos pertenecientes al ecosistema bucal y que a través del equilibrio de los mismos, se logrará un adecuado funcionamiento y desarrollo de las funciones fisiológicas en pro de la salud bucal del individuo. La presente investigación tiene como objetivo examinar los datos específicos en el uso del clavo de olor como agente bactericida en las afecciones bucodentales, encontrándose que si puede ser usado como agente bactericida por su marcado efecto sobre la microbiota oral a nivel de eliminar los microorganismos nocivos presentes en la misma, ya que actúa inhibiendo la recomposición de las proteínas, los ácidos nucleicos y la membrana de la pared celular, cambiando la permeabilidad de las células de los microorganismos, favoreciendo su muerte y a su ves favoreciendo el adecuado equilibrio de la microbiota oral, necesario para la adecuada salud bucodental(AU)

The clove (Syzygium aromaticum) is a tree, native to Indonesia, with variable height, but that exceeds 10 meters in height, belonging to the Myrtaceae family and whose flowers that have not opened, become buttons, that when drying are the aforementioned cloves. Their main component is Eugenol, among other organic compounds. Due to their biochemical and organoleptic characteristics, they provide several health benefits, for acting as stimulants, antioxidant, with antibacterial, antispasmodic action, in addition to their marked analgesic and anesthetic action. For its part, the oral microbiota is made up of a wide set of microorganisms belonging to the oral ecosystem and that through their balance, an adequate functioning and development of physiological functions will be achieved in favor of the oral health of the individual. The objective of this research is to examine the specific data on the use of cloves as a bactericidal agent in oral conditions, finding that it can be used as a bactericidal agent due to its marked effect on the oral microbiota at the level of eliminating harmful microorganisms present in it, since it acts by inhibiting the recomposition of proteins, nucleic acids and the cell wall membrane, changing the permeability of the cells of microorganisms, favoring their death and in turn favoring the proper balance of the oral microbiota, necessary for proper oral health(AU)

Hand-to-Face Contact of Preschoolers during Indoor Activities in Childcare Facilities in the Republic of Korea.

PURPOSE: This study aimed to characterize hand-to-face contact (HFC) in children and analyze the factors that affect HFC behaviors of preschoolers in childcare facilities in Korea. METHODS: Thirty preschoolers aged between 13 and 84 months were enrolled with parents' voluntary participation. Videotaping (10 children/childcare center/2 h) and video reading was performed from 23 November 2018 to 7 January 2019. RESULTS: A total of 2719 cases of HFC were observed in 30 participants within 2 h. The average contact with the facial mucosa (frequency/person/2 h) was 55.6 ± 42.2, of which the mouth (25.4 ± 23.9), the nose (20.4 ± 24.5), and the eye (9.8 ± 11.7) were the most frequent contacts, in that order. The average contact duration (sec/person/2 h) with the facial mucosa was 232.6 ± 169.7, of which the mouth (145.2 ± 150), the nose (57.6 ± 62.2), and the eyes (29.7 ± 42.3) were the longest in that order. The density distribution of the frequency and duration of mucosal contact was wider in boys than in girls. The mucosal and non-mucosal contact frequencies were significantly higher in boys (p = 0.027 and p = 0.030, respectively). CONCLUSION: Children's HFC frequency and duration were highest for the mouth, nose, and eyes. Boys tended to have a higher contact frequency than girls for both mucous and non-mucous HFC.

"I don't know whose mouth has been on this": youth nicotine and cannabis vaping practices in the context of the COVID-19 pandemic.

Early COVID-19 safety protocols urged physical and social distancing, resulting in minimal contact with others. As social contexts are central to vaping among youth, we used semi-structured interviews to describe how youth who vape are making sense of their use practices and adaptations. The qualitative analyses revealed changes in vaping frequency and access, social isolation shaping substance- and product-specific use, and motivations and outcomes of dual use of nicotine and cannabis which were closely linked to the pandemic. The findings indicate variation of youth vaping experiences within the early stages of the pandemic that should be attended to in future studies.

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

BACKGROUND: Some oral lesions have been described in patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2); the possibility has been raised that the buccal lesions observed in patients with the coronavirus disease 2019 (COVID-19) are due to this virus and the patient's systemic condition. The aim of this review was to integrate the knowledge related to the oral lesions associated with COVID-19 and the participation of the buccal cavity in the establishment of immunity against SARS-CoV-2. METHODS: A literature search on the manifestations of buccal lesions from the beginning of the pandemic until October 2021 was carried out by using the PubMed database. A total of 157 scientific articles were selected from the library, which included case reports and reports of lesions appearing in patients with COVID-19. RESULTS: Oral lesions included erosions, ulcers, vesicles, pustules, plaques, depapillated tongue, and pigmentations, among others. The oral cavity is a conducive environment for the interaction of SARS-CoV-2 with the mucosal immune system and target cells; direct effects of the virus in this cavity worsen the antiviral inflammatory response of underlying oral disorders, immunodeficiencies, and autoimmunity primarily. CONCLUSIONS: The oral cavity is an accessible and privileged environment for the interaction of SARS-CoV-2 with the mucosal immune system and target cells; the direct effects of the virus in this cavity worsen the antiviral inflammatory response of underlying oral disorders, in particular those related to immunodeficiencies and autoimmunity.

Impact of face masks and sunglasses on emotion recognition in South Koreans.

Due to the prolonged COVID-19 pandemic, wearing masks has become essential for social interaction, disturbing emotion recognition in daily life. In the present study, a total of 39 Korean participants (female = 20, mean age = 24.2 years) inferred seven emotions (happiness, surprise, fear, sadness, disgust, anger, surprise, and neutral) from uncovered, mask-covered, sunglasses-covered faces. The recognition rates were the lowest under mask conditions, followed by the sunglasses and uncovered conditions. In identifying emotions, different emotion types were associated with different areas of the face. Specifically, the mouth was the most critical area for happiness, surprise, sadness, disgust, and anger recognition, but fear was most recognized from the eyes. By simultaneously comparing faces with different parts covered, we were able to more accurately examine the impact of different facial areas on emotion recognition. We discuss the potential cultural differences and the ways in which individuals can cope with communication in which facial expressions are paramount.

Novel impacts of saliva with regard to oral health.

The maintenance of balanced oral homeostasis depends on saliva. A readily available and molecularly rich source of biological fluid, saliva fulfills many functions in the oral cavity, including lubrication, pH buffering, and tooth mineralization. Saliva composition and flow can be modulated by different factors, including circadian rhythm, diet, age, drugs, and disease. Recent events have revealed that saliva plays a central role in the dissemination and detection of the SARS-CoV-2 coronavirus. A working knowledge of saliva function and physiology is essential for dental health professionals.

Association of perturbation of oral bacterial with incident of Alzheimer's disease: A pilot study.

OBJECTIVE: This case-control study was designed to compare the composition of the predominant oral bacterial microbiome in Alzheimer's disease (AD) and control group. SUBJECT: A total of 30 adult participants (15 AD and 15 healthy individuals) were entered in this study. The composition of oral bacterial microbiome was examined by quantitative real-time polymerase chain reaction (qPCR) using bacterial 16S rDNA gene. The levels of systemic inflammatory cytokines in both groups were assessed using enzyme-linked immunosorbent assays (ELISA). RESULTS: The loads of Porphyromonas gingivalis, Fusobacterium nucleatum, and Prevotella intermedia were significantly more abundant in the AD compared to the control group (p < 0.05). Although Aggregatibacter actinomycetemcomitans and Streptococcus mutans were relatively frequent in the AD group, no significance difference was observed in their copy number between two groups. Although the concentrations of IL-1, IL-6, and TNF-α were higher in the AD group, there was a significant difference in their levels between the two groups (p < 0.05). Finally, there was a significant relationship between increased number of pathogenic bacteria in oral microbiome and higher concentration of cytokines in patient's blood. CONCLUSION: Our knowledge of oral microbiome and its exact association with AD is rather limited; our study showed a significant association between changes in oral microbiome bacteria, increased inflammatory cytokines, and AD.

Efficacy and hazards of 425 nm oral cavity light dosing to inactivate SARS-CoV-2.

OBJECTIVE: Using a battery of preclinical tests to support development of a light-based treatment for COVID-19, establish a range of 425 nm light doses that are non-hazardous to the tissues of the oral cavity and assess whether a 425 nm light dose in this non-hazardous range can inactivate SARS-CoV-2 in artificial saliva. METHODS: The potential hazards to oral tissues associated with a range of acute 425 nm light doses were assessed using a battery of four preclinical tests: (1) cytotoxicity, using well-differentiated human large airway and buccal epithelial models; (2) toxicity to commensal oral bacteria, using a panel of model organisms; (3) light-induced histopathological changes, using ex vivo porcine esophageal tissue, and (4) thermal damage, by dosing the oropharynx of intact porcine head specimens. Then, 425 nm light doses established as non-hazardous using these tests were evaluated for their potential to inactivate SARS-CoV-2 in artificial saliva. RESULTS: A dose range was established at which 425 nm light is not cytotoxic in well-differentiated human large airway or buccal epithelial models, is not cytotoxic to a panel of commensal oral bacteria, does not induce histopathological damage in ex vivo porcine esophageal tissue, and does not induce thermal damage to the oropharynx of intact porcine head specimens. Using these tests, no hazards were observed for 425 nm light doses less than 63 J/cm2 delivered at irradiance less than 200 mW/cm2. A non-hazardous 425 nm light dose in this range (30 J/cm2 at 50 mW/cm2) was shown to inactivate SARS-CoV-2 in vitro in artificial saliva. CONCLUSION: Preclinical hazard assessments and SARS-CoV-2 inactivation efficacy testing were combined to guide the development of a 425 nm light-based treatment for COVID-19. CLINICAL SIGNIFICANCE: The process used here to evaluate the potential hazards associated with 425 nm acute light dosing of the oral cavity to treat COVID-19 can be extended to other wavelengths, anatomical targets, and therapeutic applications to accelerate the development of novel photomedicine treatments.