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Salivary proteins play an important role in repairing mechanisms of damaged tissues and the maintenance of oral health. However, there is a dearth of information in the literature regarding the concentrations of salivary proteins in caries-free (CF) and caries-active (CA) subjects. Hence, this systematic review was conducted to update our previous systematic review published in 2013 that aimed to assess the association between caries and salivary proteins by comparing CF and CA individuals. Thereby, evaluating the possibility of whether salivary proteins can be regarded as biomarkers for caries. An extensive search of studies was conducted using PubMed, EMBASE, Clarivate Analytics’ Web of Science, and Elsevier’s Scopus between July 2012 and January 2022, without any language restriction. Manual searching in Google Scholar and evaluation of bibliographies of the included studies were also undertaken. The Newcastle-Ottawa Scale was used to assess the risk of bias (RoB) within the included studies. Of 22 included studies, 1,551 human subjects (range: 30–213 participants) were recruited, of which 848 individuals (54.7%) were CA and 703 (45.3%) were CF. Regarding the utilization of DMFT as the caries index, high variability was observed across different articles. A statistically significant increase in the salivary levels of alpha-amylase, acidic proline-rich protein-1, histatin-5, lactoperoxidase, and mucin-1 was found in CA patients, while the salivary levels of carbonic anhydrase 6, proteinase-3, and statherin were observed to be significantly increased in CF subjects. Conflicting results were found regarding the salivary levels of immunoglobulin A and total proteins among CA and CF subjects. The included studies were categorized as low RoB (n = 15), medium RoB (n = 4), and high RoB (n = 3). Due to significant heterogeneity among the included studies, no meta-analysis could be performed. In conclusion, the salivary levels of protein(s) might be a useful biomarker for caries diagnosis, especially alpha-amylase, acidic proline-rich protein-1, histatin-5, lactoperoxidase, mucin-1, carbonic anhydrase 6, proteinase-3, and statherin. However, their diagnostic value must be verified by large-scale prospective studies.

Dental caries is a multifactorial chronic disease resulting from the intricate interplay among acid-generating bacteria, fermentable carbohydrates, and several host factors such as saliva. Saliva comprises several proteins which could be utilized as biomarkers for caries prevention, diagnosis, and prognosis. Mass spectrometry-based salivary proteomics approaches, owing to their sensitivity, provide the opportunity to investigate and unveil crucial cariogenic pathogen activity and host indicators and may demonstrate clinically relevant biomarkers to improve caries diagnosis and management. The present review outlines the published literature of human clinical proteomics investigations on caries and extensively elucidates frequently reported salivary proteins as biomarkers. This review also discusses important aspects while designing an experimental proteomics workflow. The protein-protein interactions and the clinical relevance of salivary proteins as biomarkers for caries, together with uninvestigated domains of the discipline are also discussed critically.

Objectives: This study is aimed at describing changes in salivary flow rate and ionic composition present in the saliva of chronic kidney disease (CKD) patients by assessing the pH, calcium, phosphate, and phosphorus concentrations and comparing them to healthy individuals, along with exploring the influence of hemodialysis on these parameters. Methods: The bibliographical search was performed in nine databases to find all types of studies, including observational clinical studies, without restrictions regarding publication year or language. Two reviewers selected the studies, extracted the data, and assessed the risk of bias using JBI tools. Random-effect meta-analysis was performed with the standardized mean difference (SMD) as effect estimate, at a 95% confidence interval. Results: Thirty-three studies were included in the qualitative synthesis and 31 studies were included in the meta-analysis. Chronic kidney disease patients presented lower salivary flow rate (SMD: − 1.73; 95% CI = − 2.14; − 1.31), higher pH (SMD: 1.57; 95% CI = 1.11; 2.03), and higher phosphorus concentration (SMD: 0.86; 95% CI = 0.63; 1.09) in saliva. Concurrently, salivary flow rate and pH presented significant changes after hemodialysis, with higher salivary flow rate (SMD: 0.53; 95% CI = 0.25; 0.81) and lower pH (SMD: − 0.53; 95% CI = − 0.88; − 0.19) in patients on hemodialysis treatment. Conclusion: Chronic kidney disease patients present reduced salivary flow rate and increased pH and phosphorus concentration in saliva. Hemodialysis can increase the salivary flow rate of these patients.

Graphical abstract, Objective Viruses on environmental surfaces, in saliva and other body fluids represent risk of contamination for general population and healthcare professionals. The development of vaccines and medicines is costly and time consuming. Thus, the development of novel materials and technologies to decrease viral availability, viability, infectivity, and to improve therapeutic outcomes can positively impact the prevention and treatment of viral diseases. Methods Herein, we discuss (a) interaction mechanisms between viruses and materials, (b) novel strategies to develop materials with antiviral properties and oral antiviral delivery systems, and (c) the potential of artificial intelligence to design and optimize preventive measures and therapeutic regimen. Results The mechanisms of viral adsorption on surfaces are well characterized but no major breakthrough has become clinically available. Materials with fine-tuned physical and chemical properties have the potential to compromise viral availability and stability. Emerging strategies using oral antiviral delivery systems and artificial intelligence can decrease infectivity and improve antiviral therapies. Significance Emerging viral infections are concerning due to risk of mortality, as well as psychological and economic impacts. Materials science emerges for the development of novel materials and technologies to diminish viral availability, infectivity, and to enable enhanced preventive and therapeutic strategies, for the safety and well-being of humankind.

To assess the effectiveness of different anesthetic solutions for pain control immediately after the extraction of lower third molars. Nine databases were used to identify randomized clinical trials, without restriction of language or year of publication. The “JBI Critical Appraisal Tools for Systematic Reviews” was used to assess the risk of bias in the studies. The network meta-analysis was performed to compare the effectiveness of different anesthetics to control the pain immediately after the surgery of lower third molars, using the standardized mean difference (SMD) as the effect estimate. The GRADE approach was used to assess the certainty of evidence. The search presented 13,739 initial results, from which 45 met the eligibility criteria and presented low to moderate risk of bias. Thirteen studies were included in the meta-analysis. The 2% lidocaine + clonidine presented the lowest pain scores (SMD = − 1.44; − 2.72 to − 0.16) compared to 4% articaine + adrenaline, followed by 0.5% bupivacaine + adrenaline (SMD = − 1.36; − 2.13 to − 0.59). The certainty of evidence varied between very low to moderate. 2% lidocaine + clonidine and 0.5% bupivacaine + adrenaline were the anesthetics with the highest probability for pain control immediately after the surgical procedure of removing impacted lower third molars. The use of an adequate anesthetic with effective pain control can contribute to a more comfortable postoperative period.

Neutrophils, cells of the innate immune system, enter the mouth and release factors that are hypothesized to contribute to the degradation of tooth dentin, methacrylate resin composites, and adhesives at the restoration-tooth-dentin interface. The objectives were to characterize neutrophils' degradation towards resin composite, self-etch (SE) and total-etch (TE) adhesives, SE and TE resin-dentin interfaces and to identify proteins that could contribute to the degradation process. Neutrophils' degradation of cured resin composite, and SE and TE adhesives, was quantified by measuring the specific resin degradation by-product, bishydroxy-propoxy-phenyl-propane (bisHPPP), released after 30 days incubation of the materials with the cells. Neutrophils' degradative effect on resin-dentin interfaces was examined by recording the interfacial fracture toughness (FT), and surface analysis of the fracture mode following incubation of SE and TE miniature short-rod (mini-SR) specimens with the cells. Neutrophils increased degradation of polymerized resin composite, and TE adhesive, but not SE adhesive over 30 days (p 0.05). Incubation of SE and TE resin-dentin interfaces with neutrophils led to a reduction in FT over time (p 0.05). The effect was more pronounced for TE interfaces. Neutrophils also affected the fracture mode of SE and TE resin-dentin interfaces. Several proteins that could contribute to the degradative activity of neutrophils, including Neutrophil collagenase (MMP-8), Matrix metalloproteinase- 9 (MMP-9), Cathepsin G, Neutrophil- gelatinase associated lipocalin (NGAL) and Myeloperoxidase, were isolated. The ability of neutrophils to degrade resin, tooth dentin, and reduce the bond strength of resin-dentin interfaces suggest neutrophils' potential role in primary and recurrent caries and dental restoration failure.

To evaluate whether surface characteristics of different titanium modifications may influence the composition of the salivary pellicle on each surface by analyzing the salivary proteome through mass spectrometry–based proteomics. Titanium discs with three surfaces modifications (PT (machined titanium), SLA (sandblasted/large-grit/acid-etched), and SLActive (modified SLA)) were characterized (topography, chemistry, and energy) prior to being exposed to saliva for 2 h to form a protein pellicle. The resultant protein layer was retrieved and analyzed through mass spectrometry (nLC-ESI-MS/MS) to examine the surface specificity for protein binding, while the proteome profile of each surface was classified. The proteome analysis showed that the salivary pellicle composition was more complex on rough surfaces (SLA and SLActive). Although variability in protein composition was observed between surfaces, most proteins were detected on more than one surface, indicating a limited surface specificity for protein binding. Additionally, the salivary pellicle formed on the SLActive presented a larger number of proteins associated with immune response, biological adhesion, and biomineralization. Although topography, chemistry, and energy differed between the surfaces, they were not determinant to produce a salivary pellicle with high surface specificity. Also, we showed that several salivary proteins adsorbed on Ti surfaces are involved in biological functions important to the biointegration. This study sheds light on the necessity for the development of bioactive surfaces that favors the formation of a specific protein layer that can enhance tissue response to assist the biointegration of dental implants.

Background Dogs’ saliva is a complex mixture of inorganic and organic constituents, rich in proteins. Therefore, knowing the saliva composition of these animals is extremely important to identify the presence of proteins that may be involved in physiological and pathological mechanisms of their oral cavity. The present study aimed to characterize the proteomic profile of saliva from dogs with and without dental calculus. Results Saliva samples were collected from 20 dogs. Before the collection, a visual clinical examination was performed and 8 subjects (40%) did not present any signs of dental calculus, while 12 (60%) presented dental calculus. After saliva collection, the samples were submitted to protein quantification (mBCA), and then they were prepared for analysis by nLC-ESI-MS/MS. A total of 658 unique proteins were identified, of which 225 were specific to dogs without dental calculus, 300 were specific to dogs with dental calculus, and 133 were common to all subjects. These proteins presented functions including transportation, immune response, structural, enzymatic regulation, signal transduction, transcription, metabolism, and some proteins perform functions as yet unknown. Several salivary proteins in dogs with dental calculus differed from those found in the group without dental calculus. Among the abundant proteins detected in periodontal affected cases, can be highlighting calcium-sensing receptor and transforming growth factor beta. Enrichment analysis reveled the presence of Rho GTPases signaling pathway. Conclusions This research identified salivary proteins, that should be further investigated as potencial biomarkers of chronic periodontits with dental calculus formation in dogs.

This study is aimed at describing changes in salivary flow rate and ionic composition present in the saliva of chronic kidney disease (CKD) patients by assessing the pH, calcium, phosphate, and phosphorus concentrations and comparing them to healthy individuals, along with exploring the influence of hemodialysis on these parameters.The bibliographical search was performed in nine databases to find all types of studies, including observational clinical studies, without restrictions regarding publication year or language. Two reviewers selected the studies, extracted the data, and assessed the risk of bias using JBI tools. Random-effect meta-analysis was performed with the standardized mean difference (SMD) as effect estimate, at a 95% confidence interval.Thirty-three studies were included in the qualitative synthesis and 31 studies were included in the meta-analysis. Chronic kidney disease patients presented lower salivary flow rate (SMD: - 1.73; 95% CI = - 2.14; - 1.31), higher pH (SMD: 1.57; 95% CI = 1.11; 2.03), and higher phosphorus concentration (SMD: 0.86; 95% CI = 0.63; 1.09) in saliva. Concurrently, salivary flow rate and pH presented significant changes after hemodialysis, with higher salivary flow rate (SMD: 0.53; 95% CI = 0.25; 0.81) and lower pH (SMD: - 0.53; 95% CI = - 0.88; - 0.19) in patients on hemodialysis treatment.Chronic kidney disease patients present reduced salivary flow rate and increased pH and phosphorus concentration in saliva. Hemodialysis can increase the salivary flow rate of these patients.

In vitro biofilm models have been extensively used, but only few of the models available to date had been validated in terms of the dose-response effect of anti-caries and/or antimicrobial substances. Additionally, none of the validated models allow the use of microliter volumes of the treatment solutions, needed mainly to test (screen) novel but expensive substances under development. This study aimed at modifying an in vitro cariogenic Streptococcus mutans biofilm model and validating it by assessing the dose-response effect of fluoride on enamel demineralization. S. mutans cariogenic biofilms were developed on saliva-coated enamel slabs previously bonded to acrylic holders fixed to a lid of a culture plate. Biofilms were incubated 8 h/day in culture medium supplemented with 1% sucrose and then overnight in culture medium with glucose 0.1 mM. Biofilms were also treated 2×/day with 2.0 mL of solutions containing 0, 125, 275 and 1250 μg F/mL (n = 10/group). The replaced culture medium was used to: determine the biofilm acidogenicity; estimate the demineralization of enamel; and monitor the fluoride concentration. At 144 h, biofilms were collected for fluoride concentration analyses, and the fluoride uptake by enamel was determined in each slab. The model showed a dose-response effect of fluoride (R2 = 0.96, p

Oral health care settings carry a potentially high risk of causing cross-infection between dentists and patients and among dental staff members due to close contact and use of aerosol-generating procedures. The authors aimed to estimate COVID-19 incidence rates among Canadian dentists over a 6-month period.The authors conducted a prospective cohort study of 644 licensed dentists across Canada from July 29, 2020, through February 12, 2021. An online questionnaire, adapted from the World Health Organization's Unity Studies protocols for assessment of COVID-19 risk among health care workers, was used to collect data on self-reported severe acute respiratory syndrome coronavirus 2 infections every 4 weeks. A bayesian Poisson model was used to estimate the incidence rate and corresponding 95% credible intervals (CIs).Median age of participants was 47 years; most participants were women (56.4%) and general practitioners (90.8%). Median follow-up time was 188 days. Six participants reported COVID-19 infections during the study period, giving an incidence rate of 5.10 per 100,000 person-days (95% CI, 1.86 to 9.91 per 100,000 person-days). The incidence proportion was estimated to be 1,084 per 100,000 dentists (95% CI, 438 to 2,011 per 100,000 dentists) and 1,864 per 100,000 people (95% CI, 1,859 to 1,868 per 100,000 people) in the Canadian population during the same period.The low infection rate observed among Canadian dentists from July 29, 2020, through February 12, 2021, should be reassuring to the dental and general community.Although the infection rates were low among Canadian dentists, it is important to continue to collect disease surveillance data.

Dental caries has been the most widespread chronic disease globally associated with significant health and financial burdens. Caries typically starts in the enamel, which is a unique tissue that cannot be healed or regrown; nonetheless, new preventive approaches have limitations and no effective care has developed yet. Since enamel is a non-renewable tissue, we believe that the intimate overlaying layer, the acquired enamel pellicle (AEP), plays a crucial lifetime protective role and could be employed to control bacterial adhesion and dental plaque succession. Based on our identified AEP whole proteome/peptidome, we investigated the bioinhibitory capacities of the native abundant proteins/peptides adsorbed in pellicle-mimicking conditions. Further, we designed novel hybrid constructs comprising antifouling and antimicrobial functional domains derived from statherin and histatin families, respectively, to attain synergistic preventive effects. Three novel constructs demonstrated significant multifaceted bio-inhibition compared to either the whole saliva and/or its native proteins/peptides via reducing biomass fouling and inducing biofilm dispersion beside triggering bacterial cell death. These data are valuable to bioengineer precision-guided enamel pellicles as an efficient and versatile prevention remedy. In conclusion, integrating complementary acting functional domains of salivary proteins/peptides is a novel translational approach to design multifunctional customizable enamel pellicles for caries prevention.

Mandatory attendance, particularly in didactic settings, is a highly debated topic in higher education, including dental education. Within dental education, a large portion of education occurs in preclinical laboratories and clinical environments. There is little to no research on attendance in these settings in dental schools. This point/counterpoint paper examines the pros and cons of mandatory attendance in these highly specialized educational settings. With the backdrop of the COVID-19 pandemic that began in March 2020 and continues to impact dental education at the time of publication, this topic has become even more relevant. Viewpoint 1 claims that attendance should be mandatory because a greater exposure to preclinical and clinical environments helps foster better clinical hand skills, critical thinking, decision-making, problem-solving skills, and an overall sense of professional identity. It goes on further to suggest that there may be a link between attendance and performance in exams and that attendance is part of the dental school's responsibility. Viewpoint 2 argues that the rationale for attendance is complex, and that creating learning environments that are psychologically safe will incentivize students to attend, even without mandatory attendance policies. Furthermore, it explains that technological advances have allowed dental schools to think creatively about asynchronous learning, which by its very nature does not require attendance at a given time. The authors of both viewpoints conclude that the preclinical and clinical education and experience are critical dental education and that dental school leaders should focus on improving the quality of these experiences.

The aim of this study was to assess and compare RANK, RANKL, and OPG immunoexpression in dentigerous cyst, odontogenic keratocyst, and ameloblastoma. The protocol was registered in PROSPERO (CRD42018105543). Seven databases (Embase, Lilacs, LIVIVO, PubMed, Scopus, SciELO, and Web of Science) were the primary search sources and two databases (Open Grey and Open Thesis) partially captured the “grey literature”. Only cross sectional studies were included. The JBI Checklist assessed the risk of bias. A meta-analysis with random effects model estimated the values from the OPG and RANKL ratio reported by the individual studies and respective 95% confidence intervals. The heterogeneity among studies was assessed with I2 statistics. Only nine studies met the inclusion criteria and were considered in the analyses. The studies were published from 2008 to 2018. Two studies presented low risk of bias, while seven studies presented moderate risk. The meta-analysis showed the highest OPG>RANKL ratio for dentigerous cyst (ES=43.3%; 95% CI=14.3-74.8) and odontogenic keratocyst (ES=36.8%; 95% CI=18.8-56.7). In contrast, the highest OPG RANKL para cisto dentígero (ES=43,3%; IC95%=14,3-74,8) e ceratocisto odontogênico (ES=36,8%; IC95%=18,8-56,7). Por outro lado, a maior razão OPG

Hydrogen peroxide (H2O2)-based products are effective in tooth whitening; however, their safety is controversial as they may harm patient tissues/cells. These effects are suggested to be concentration-dependent; nonetheless, to date, there are no reports on H2O2-mediated oxidative damage in the gingival tissue, and neither whether this can be detected in gingival crevicular fluid (GCF) samples. We hypothesize that H2O2 whitening products may cause collateral oxidative tissue damage following in office application. Therefore, H2O2 and nitric oxide (NO) levels were investigated in GCF samples obtained from patients undergoing dental bleaching with H2O2 at different concentrations, in a randomized, double-blind, split-mouth clinical trial. A proteomic analysis of these samples was also performed. H2O2-based whitening products promoted inflammation which was detected in GCF samples and lasted for longer following 35% H2O2 bleaching. This included time-dependent changes in NO levels and in the abundance of proteins associated with NO synthesis, oxidative stress, neutrophil regulation, nucleic acid damage, cell survival and/or tissue regeneration. Overall, H2O2-based products used in office promote inflammation irrespective of their concentration. As the inflammation caused by 35% H2O2 is longer, patients may benefit better from using lower concentrations of this bleaching product, as they may result in less tissue damage.

Background Dental care settings potentially carry a high risk of cross-infection between dentists and patients and among dental staff due to close contact and use of aerosol-generating procedures. This study aimed to estimate COVID-19 incidence rates among Canadian dentists over a six-month period. Methods We conducted a prospective cohort study of 644 licensed dentists across Canada, from 29th July 2020 to 12th February 2021. An online questionnaire, adopted from WHO Unity Study protocols for assessment of COVID-19 risk among healthcare workers was used to collect self-reported SARS-CoV-2 infection, every four weeks. Bayesian Poisson model was used to estimate the incidence rate and corresponding 95% credible intervals (CI). Results The median age of participants was 47 years, with the majority being female (56.4%) and general practitioners (90.8%). The median follow-up time was 188 days. Six participants reported COVID-19 infection during the study period, giving an incidence rate of 5.10 per 100,000 person-days (95% CI = 1.86 – 9.91 per 100,000 person-days). The incidence proportion was estimated to be 1084 per 100,000 dentists (95% CI = 438 to 2011 per 100,000), while it was 1864 per 100,000 persons (95% CI = 1859 to 1868 per 100,000 persons) in the Canadian population during the same period. Conclusion The low infection rate observed among Canadian dentists over the period July 2020 to February 2021 is reassuring to the dental and general community.

SARS-CoV-2 is a novel respiratory virus that has quickly spread across the globe. The virus uses a protein called Spike and its associated receptor binding domain (RBD) to interact with angiotensin converting enzyme-2 (ACE-2) on the surface of epithelial cells in the respiratory tract. Although a definite correlate of protection against COVID-19 has yet to emerge, many studies have quantified anti-Spike and anti-RBD IgG antibody (Ab) levels, as well as neutralizing Ab in the blood to ascertain immunity. This approach misses out on Ab that are produced in the upper respiratory tract (URT) mucosa – the site of viral encounter. Whether intramuscularly (i.m.) administered COVID-19 vaccines can promote immunity in the mucosa is not well understood. We recently completed a study where we showed that anti-Spike/RBD IgG could be detected in the saliva following i.m. vaccination with either two doses of mRNA vaccines (Pfizer or Moderna) or with a heterologous dosing of Astra Zeneca followed by an mRNA vaccine. Administration of a second dose of mRNA boosted the IgG but not IgA response, with only 30% of participants remaining positive for IgA at this timepoint. At 6 months post-dose 2, these participants had diminished anti-Spike/RBD IgG levels, although secretory component associated anti-Spike Ab were more stable. Examining two prospective cohorts we found that participants who experienced breakthrough infections with SARS-CoV-2 had lower levels of vaccine-induced serum anti-Spike/RBD IgA at 2–4 weeks post-dose 2 compared to participants who did not experience an infection, whereas IgG levels were comparable between groups. These data suggest that COVID-19 vaccines that elicit a durable IgA response may have utility in preventing infection. We received funding support from CIHR (Fund #15992), a COVID-19 Immunity Task force grant, an “Ontario Together” province of Ontario grant, a CIHR team grant to CoVARR-Net, a Donation from the Royal Bank of Canada (RBC) and a donation from the Krembil Foundation to the Sinai Health System Foundation.

Salivary proteins such as histatins (HTNs) have demonstrated critical biological functions directly related to tooth homeostasis and prevention of dental caries. However, HTNs are susceptible to the high proteolytic activities in the oral environment. Therefore, pH-sensitive chitosan nanoparticles (CNs) have been proposed as potential carriers to protect proteins from enzymatic degradation at physiological salivary pH. Four different types of chitosan polymers were investigated and the optimal formulation had good batch to batch reproducibility, with an average hydrodynamic diameter of 144 ± 6 nm, a polydispersity index of 0.15 ± 0.04, and a zeta potential of 18 ± 4 mV at a final pH of 6.3. HTN3 encapsulation and release profiles were characterized by cationic polyacrylamide gel electrophoresis. The CNs successfully encapsulated HTN3 and selectively swelled at acidic pH to facilitate HTN3 release. Protection of HTN3 against enzymatic degradation was investigated in diluted whole saliva. HTN3 encapsulated in the CNs had a prolonged survival time compared to the free HTN3. CNs with and without HTN3 also successfully reduced biofilm weight and bacterial viability. The results of this study have demonstrated the suitability of CNs as potential protein carriers for oral applications, especially for complications occurring at acidic conditions.

The aim of this study was to investigate the atomic composition and the proteome of the salivary proteins adsorbed on the surface of orthodontic metallic bracket. For this, the atomic composition of orthodontic metallic brackets was analyzed with X-ray Photoelectron Spectroscopy (XPS). The acquired bracket pellicle was characterized after brackets were immersed in human whole saliva supernatant for 2 hours at 37°C. Hydroxyapatite (HA) discs were used as a control. Acquired pellicle was harvested from the HA discs (n = 12) and from the metallic brackets (n = 12). Proteomics based on mass spectrometry technology was used for salivary protein identification and characterization. Results showed that most of the proteins adsorbed on the surface of orthodontic metallic brackets and on the HA discs were identified specifically to each group, indicating a small overlapping between the salivary proteins on each study group. A total of 311 proteins present on the HA discs were unique to this group while 253 proteins were unique to metallic brackets, and only 45 proteins were common to the two groups. Even though most proteins were unique to each study group, proteins related to antimicrobial activity, lubrication, and remineralization were present in both groups. These findings demonstrate that the salivary proteins adsorbed on the bracket surface are dependent on the material molecular composition.

Saliva is an alternative biofluid to serum for detecting and monitoring IgG to SARS-CoV-2 spike and RBD antigens in COVID-19., While the antibody response to SARS-CoV-2 has been extensively studied in blood, relatively little is known about the antibody response in saliva and its relationship to systemic antibody levels. Here, we profiled by enzyme-linked immunosorbent assays (ELISAs) IgG, IgA and IgM responses to the SARS-CoV-2 spike protein (full length trimer) and its receptor-binding domain (RBD) in serum and saliva of acute and convalescent patients with laboratory-diagnosed COVID-19 ranging from 3–115 days post-symptom onset (PSO), compared to negative controls. Anti-SARS-CoV-2 antibody responses were readily detected in serum and saliva, with peak IgG levels attained by 16–30 days PSO. Longitudinal analysis revealed that anti-SARS-CoV-2 IgA and IgM antibodies rapidly decayed, while IgG antibodies remained relatively stable up to 105 days PSO in both biofluids. Lastly, IgG, IgM and to a lesser extent IgA responses to spike and RBD in the serum positively correlated with matched saliva samples. This study confirms that serum and saliva IgG antibodies to SARS-CoV-2 are maintained in the majority of COVID-19 patients for at least 3 months PSO. IgG responses in saliva may serve as a surrogate measure of systemic immunity to SARS-CoV-2 based on their correlation with serum IgG responses.

While the antibody response to SARS-CoV-2 has been extensively studied in blood, relatively little is known about the mucosal immune response and its relationship to systemic antibody levels. Since SARS-CoV-2 initially replicates in the upper airway, the antibody response in the oral cavity is likely an important parameter that influences the course of infection, but how it correlates to the antibody response in serum is not known. Here, we profile by enzyme linked immunosorbent assays (ELISAs) IgG, IgA and IgM responses to the SARS-CoV-2 spike protein (full length trimer) and its receptor binding domain (RBD) in serum (n=496) and saliva (n=90) of acute and convalescent patients with laboratory-diagnosed COVID-19 ranging from 3–115 days post-symptom onset (PSO), compared to negative controls. Anti-CoV-2 antibody responses were readily detected in serum and saliva, with peak IgG levels attained by 16–30 days PSO. Whereas anti-CoV-2 IgA and IgM antibodies rapidly decayed, IgG antibodies remained relatively stable up to 105 days PSO in both biofluids. In a surrogate neutralization ELISA (snELISA), neutralization activity peaks by 31–45 days PSO and slowly declines, though a clear drop is detected at the last blood draw (105–115 days PSO). Lastly, IgG, IgM and to a lesser extent IgA responses to spike and RBD in the serum positively correlated with matched saliva samples. This study confirms that systemic and mucosal humoral IgG antibodies are maintained in the majority of COVID-19 patients for at least 3 months PSO. Based on their correlation with each other, IgG responses in saliva may serve as a surrogate measure of systemic immunity.One Sentence SummaryIn this manuscript, we report evidence for sustained SARS-CoV-2-specific IgG and transient IgA and IgM responses both at the site of infection (mucosae) and systemically in COVID-19 patients over 3 months and suggest that saliva could be used as an alternative biofluid for monitoring IgG to SARS-CoV-2 spike and RBD antigens.

Purpose. This study evaluated the cytotoxicity of antimicrobial silver tungstate (Ag2WO4) or silver molybdate (Ag2MoO4) microcrystals coating biomaterials. Materials and Methods. The coating procedure was performed onto titanium, zirconia, and acrylic resin specimens. Eluates of the coated specimens were obtained, which were used for cytotoxicity analyses, including Alamar Blue, MTT, and CytoTox-ONE tests. Data were analyzed using two-way ANOVA, followed by the Tukey test (α = 0.05). The results of each experimental group were also compared to those of the control of living cells, taken as 100% cell viability. Results. In general, it was observed that the percentage of living cells from all biomaterials coated with both microcrystals was statistically different compared to the ones from the uncoated sample groups, except for the results from MTT of specimens of Ti coated with α-Ag2MoO4. All uncoated biomaterials were classified as noncytotoxic by the three assays used in the present study. It was observed that the microcrystals in solution were strongly cytotoxic, with death of almost 100% of cells, from the analysis of the results of the Alamar Blue assay. Conclusion. The most biomaterials coated with both microcrystals showed some degree of cytotoxicity in the different assays. The results described herein should be seen as an alert to the use of microcrystals, which can expose patients to health risks.

Cyclo-Gly-Pro (CGP) attenuates nociception, however its effects on salivary glands remain unclear. In this study, we investigated the acute effects of CGP on salivary flow and composition, and on the submandibular gland composition, compared with morphine. Besides, we characterized the effects of naloxone (a non-selective opioid receptor antagonist) on CGP- and morphine-induced salivary and glandular alterations in mice. After that, in silico analyses were performed to predict the interaction between CGP and opioid receptors. Morphine and CGP significantly reduced salivary flow and total protein concentration of saliva and naloxone restored them to the physiological levels. Morphine and CGP also reduced several infrared vibrational modes (Amide I, 1687-1594cm-1; Amide II, 1594-1494cm-1; CH2/CH3, 1488-1433cm-1; C = O, 1432-1365cm-1; PO2 asymmetric, 1290-1185cm-1; PO2 symmetric, 1135-999cm-1) and naloxone reverted these alterations. The in silico docking analysis demonstrated the interaction of polar contacts between the CGP and opioid receptor Cys219 residue. Altogether, we showed that salivary hypofunction and glandular changes elicited by CGP may occur through opioid receptor suggesting that the blockage of opioid receptors in superior cervical and submandibular ganglions may be a possible strategy to restore salivary secretion while maintaining antinociceptive action due its effects on the central nervous system.

To identify and characterize specific esterases from S. mutans with degradative activity toward methacrylate-based resin monomers.Out of several putative esterases, an esterase encoded in an Open Reading Frame as SMU_118c (The National Center for Biotechnology Information, NCBI), was found to have true hydrolase activities. SMU_118c was cloned, expressed, purified and further characterized for its respective hydrolytic activity towards ester-containing nitrophenyl substrates and the universal resin monomers bis-phenyl-glycidyl-dimethacrylate (bisGMA) and triethyleneglycol dimethacrylate (TEGDMA) at neutral (7.0) or cariogenic (5.5) pH. Mass spectrometry (MS) was used to verify the expression of SMU_118c protein in S. mutans UA159.Similar to the whole cell activity of S. mutans, SMU_118c showed the highest affinity toward para-nitrophenyl acetate (pNPA) and para-nitrophenyl butyrate (pNPB) vs. ortho-nitrophenyl butyrate (oNPB) and butyrylthiocholine iodide (BTC) (p 0.05). The esterase retained 60% of its activity after 21 days and hydrolyzed bisGMA at a higher rate than TEGDMA at both neutral and cariogenic pH (p 0.001), similarly to the predominant human salivary esterase degradative activity. MS confirmed that SMU_118c is an intracellular protein in S. mutans UA159 and expressed under pathogenic (pH 5.5) growth conditions.The similarity in the activity profile to the whole S. mutans bacterial cell, the stability over time at cariogenic pH, the preference to hydrolyze bisGMA and confirmed expression profile suggest that SMU_118c could be a significant contributor to the whole bacterial degradative activity of S. mutans toward the degradation of resin composites, adhesives and the restoration-tooth interface, potentially accelerating restoration's failure.The current study builds upon our highly-cited previous study by Bourbia et al., (JDR, 2013) that reported on that the cariogenic bacterium, S. mutans has esterase-like activities that enable the bacterium to degrade dental composites and adhesives. The current submission is the first to report on the isolation and characterization of the specific esterase activity (SMU_118c) from S. mutans that is a significant contributor to the whole bacterial degradative activity toward the hydrolysis of dental resins. This activity compromises the restoration-tooth interface, increases interfacial bacterial microleakage (Kermanshahi et al., JDR 2010), potentially contributing to the pathogenesis of recurrent caries around resin composite restorations. This represent a significant contribution to the field of biomaterials and their clinical performance.

The aim of this study was to test the hypothesis that duplication/hybridization of functional domains of naturally occurring pellicle peptides amplified the inhibitory effect of hydroxyapatite crystal growth, which is related to enamel remineralization and dental calculus formation. Histatin 3, statherin, their functional domains (RR14 and DR9), and engineered peptides (DR9-DR9 and DR9-RR14) were tested at seven different concentrations to evaluate the effect on hydroxyapatite crystal growth inhibition. A microplate colorimetric assay was used to quantify hydroxyapatite crystal growth. The half-maximal inhibitory concentration (IC50) was determined for each group. ANOVA and Student-Newman-Keuls pairwise comparisons were used to compare the groups. DR9-DR9 increased the inhibitory effect of hydroxyapatite crystal growth compared to single DR9 (p

Protein-protein interaction is a common physiological mechanism for protection and actions of proteins in an organism. The identification and characterization of protein-protein interactions in different organisms is necessary to better understand their physiology and to determine their efficacy. In a previous in vitro study using mass spectrometry, we identified 43 proteins that interact with histatin 1. Six previously documented interactors were confirmed and 37 novel partners were identified. In this tutorial, we aimed to demonstrate the usefulness of the STRING database for studying protein-protein interactions. We used an in-silico approach along with the STRING database (http://string-db.org/) and successfully performed a fast simulation of a novel constructed histatin 1 protein-protein network, including both the previously known and the predicted interactors, along with our newly identified interactors. Our study highlights the advantages and importance of applying bioinformatics tools to merge in-silico tactics with experimental in vitro findings for rapid advancement of our knowledge about protein-protein interactions. Our findings also indicate that bioinformatics tools such as the STRING protein network database can help predict potential interactions between proteins and thus serve as a guide for future steps in our exploration of the Human Interactome.Our study highlights the usefulness of the STRING protein database for studying protein-protein interactions. The STRING database can collect and integrate data about known and predicted protein-protein associations from many organisms, including both direct (physical) and indirect (functional) interactions, in an easy-to-use interface.