Impact of COVID-19 on Dental Practices in El Salvador and Mexico: A Comprehensive Survey Analysis.

BACKGROUND AND OBJECTIVES: This study aimed to identify the relationship between prevention measures and protective barriers in dental practice in El Salvador and Mexico during the COVID-19 pandemic in 2020 and 2021. MATERIALS AND METHODS: A longitudinal study was conducted from June 2020 to December 2021, involving 1,719 dentists divided into four groups based on location and year. A 20-question survey in Spanish was utilized and validated with a Cronbach's alpha value of 0.84. RESULTS: The use of phone triage (OR = 1.3), thermometers (OR = 1.4), physical distancing (OR = 1.7), and face shields (OR = 2.6) was significantly associated with dental practice in both countries during the pandemic. CONCLUSIONS: During 2020 and 2021, dental care in El Salvador and Mexico was significantly linked to COVID-19 preventive measures. Phone triage, thermometers, distancing, and face shields positively correlated with dental services. National health agencies should promote the use of minimum preventive measures in dental care, preparing for potential reinfections or new pandemics from emerging virus variants.

Application of Silver Nanoparticles to Improve the Antibacterial Activity of Orthodontic Adhesives: An In Vitro Study.

There is a significant change in the bacterial plaque populations in the oral cavity during and after orthodontic treatment. Numerous studies have demonstrated that 2−96% of patients could increase the risk of white spot lesions. Streptococcus mutans and Lactobacilli ssp. are responsible for these white spot lesions. In this work, silver nanoparticles (AgNPs) with a diameter of 11 nm and dispersed in water were impregnated onto three different commercial orthodontic adhesives at 535 µg/mL. The shear bond strength (SBS) was assessed on 180 human premolars and metallic brackets. The premolars were divided into six groups (three groups for the commercial adhesives and three groups for the adhesives with AgNPs). All the groups were tested for their bactericidal properties, and their MIC, MBC, and agar template diffusion assays were measured. After adding AgNPs, the SBS was not significantly modified for any adhesive (p > 0.05), and the forces measured during the SBS did not exceed the threshold of 6 to 8 MPa for clinical acceptability in all groups. An increase in the bactericidal properties against both S. mutans and L. acidophilus was measured when the adhesives were supplemented with AgNPs. It was concluded that AgNPs can be supplement commercial orthodontic adhesives without modifying their mechanical properties with improved bactericidal activity.

Traumatic dental injuries in 6 to 12 years old schoolchildren: a multicenter cross-sectional study in Mexico.

The aim of this study was to determine the prevalence of dental trauma in schoolchildren 6 to 12 years of age and associated clinical, sociodemographic, and socioeconomic variables. A cross-sectional study was conducted in 477 children from public elementary schools in four locations in Mexico. The dependent variable was dental trauma, which was dichotomized in 0 = without dental trauma and 1 = with dental trauma. For the statistical analysis, a multivariate binary logistic regression model was generated in Stata. Average age was 9.06±1.94 years and 51.1% were girls. The prevalence of dental trauma was 18.2%. Falls, automobile accidents and sports had the highest number of instances (p < 0.01). In the multivariate model, it was observed that the risk of dental trauma increased with age (OR = 1.28) and among boys (OR = 1.45). Schoolchildren with decreased overjet (OR = 0.38) had lower dental trauma. Father's age (OR = 1.03) and educational level (OR = 1.78) were associated with dental trauma. Schoolchildren without health insurance (OR = 0.62) presented dental trauma less often. This study provided important information regarding the association of different sociodemographic, socioeconomic and clinical variables with dental trauma in Mexican schoolchildren. Identifying factors associated with dental trauma may support health promotion opportunities to ameliorate the prevalence of dental trauma.

Proteomic analysis of an Enterococcus faecalis mutant generated against the exposure to silver nanoparticles.

INTRODUCTION: Nanoparticles (NPs) have been widely studied as an alternative to antibiotic use due to their antimicrobial properties at lower concentrations. Enterococcus faecalis is a facultative Gram-positive microorganism inhabiting the gastrointestinal tract of humans and animals. It can also be present in other environments such as the oral cavity, water, sewage, soil and food. AIMS: We evaluated whether E. faecalis could develop resistance to silver NPs (AgNPs) after exposure to sublethal concentrations of the NPs. METHODS AND RESULTS: Proteomic analyses revealed that different pathways were activated during the acquired resistance under sublethal concentrations, and selected genes were validated by qPCR. CONCLUSIONS: The results of this study showed that E. faecalis is capable of generating resistance to AgNPs. SIGNIFICANCE AND IMPACT OF THE STUDY: To avoid the generation of resistance against AgNPs, future use of these NPs should be combined with other NPs prepared with different metals to prevent the dissemination of resistant strains.

Traumatic dental injuries in 6 to 12 years old schoolchildren: a multicenter cross-sectional study in Mexico

Abstract The aim of this study was to determine the prevalence of dental trauma in schoolchildren 6 to 12 years of age and associated clinical, sociodemographic, and socioeconomic variables. A cross-sectional study was conducted in 477 children from public elementary schools in four locations in Mexico. The dependent variable was dental trauma, which was dichotomized in 0 = without dental trauma and 1 = with dental trauma. For the statistical analysis, a multivariate binary logistic regression model was generated in Stata. Average age was 9.06±1.94 years and 51.1% were girls. The prevalence of dental trauma was 18.2%. Falls, automobile accidents and sports had the highest number of instances (p < 0.01). In the multivariate model, it was observed that the risk of dental trauma increased with age (OR = 1.28) and among boys (OR = 1.45). Schoolchildren with decreased overjet (OR = 0.38) had lower dental trauma. Father's age (OR = 1.03) and educational level (OR = 1.78) were associated with dental trauma. Schoolchildren without health insurance (OR = 0.62) presented dental trauma less often. This study provided important information regarding the association of different sociodemographic, socioeconomic and clinical variables with dental trauma in Mexican schoolchildren. Identifying factors associated with dental trauma may support health promotion opportunities to ameliorate the prevalence of dental trauma.

Antimicrobial Activity of 3D-Printed Acrylonitrile Butadiene Styrene (ABS) Polymer-Coated with Silver Nanoparticles.

Medical devices with antimicrobial properties are a potential long-term solution to the high rate of multi-drug-resistant healthcare-associated infections. Silver nanoparticles (AgNPs) are an established agent for effectively eliminating a wide range of microbial strains. AgNPs have been commonly incorporated into traditional plastic materials; however, recently, there has been increased interest in using AgNPs combined with 3D-printing technology for medical devices due to the accessibility and customizability of 3D-printed products. This study reports a novel method of utilizing acetone to partially dissolve 3D-printed polymer acrylonitrile butadiene styrene (ABS) plastic to attach a layer of AgNPs. The antimicrobial properties of this AgNP-coated surface were tested against several microbial strains prevalent in healthcare-associated infections. AgNP-coated ABS (AgNP-ABS) plastic demonstrated significant elimination of viable bacteria within 4 h for all tested bacterial species (Acinetobacter baumannii, non-pathogenic and pathogenic Escherichia coli, Pseudomonas aeruginosa, and methicillin-resistant Staphylococcus aureus) and within 19 h for the tested fungus Candida albicans. The longevity of adhesion of AgNPs to the ABS plastic was assessed by checking antibacterial activity against A. baumannii after repeat use cycles. AgNP-ABS plastic showed decreased antibacterial efficacy with repeated use but maintained the ability to eliminate microbes within 3 h for up to eight use cycles. The AgNP-coated ABS plastic showed efficacy as an antimicrobial surface, and future studies will consider its applicability in the production of medical devices.

Effect of sodium hypochlorite in ground fluorotic enamel: Shear bond strength and surface analysis / Efecto del hipoclorito de sodio en esmalte fluorótico tallado: resistencia adhesiva al cizallamiento y análisis de la superficie

ABSTRACT: Evaluate the effect on the shear bond strength (SBS) of 5% NaOCl applied after acid etching on ground anterior teeth with fluorosis and analyze the surface with scanning electron microscopy (SEM), also compare fluorotic and healthy ground enamel by atomic force microscopy (AFM) and Vickers microhardness (VM). For the SBS test 30 anterior teeth with moderate and severe fluorosis according Dean index were selected by an examiner previously calibrated with an expert in fluorosis by using the intraclass correlation coefficient (ICC). With the help of a calibrated high speed diamond bur for veneer preparation and a parallel chamfer high speed diamond bur he vestibular face was prepared with a uniform reduction of .3 mm under water cooling. In one half of the vestibular face of the teeth the conventional adhesive procedure was carried out while in the other half was added an additional step with 5% NaOCl applied for 1 minute and washing after acid etchant. A resin post was adhered in each half and load was applied until fracture. The failure mode was evaluated and a SEM analysis was made. Posteriorly 10 samples of fluorotic and healthy ground enamel were used to measure the nanostructural characteristics by AFM (roughness average and absolute depth profile) and the VM in three operative steps (after ground, after etchant and after deproteinization). The Shapiro-Wilks and Brown-Forsythe methods were used to test the distribution of variables. The Paired Student's t-test was used to compare the differences between mean bond strength (MPa) in the two groups for SBS test. Chi- square analyzes were performed to compare the failure modes between groups. One- way ANOVA analysis and Tukey-Kramer post hoc test were used to compare groups for roughness average, absolute depth profile and Vickers microhardness. A greater SBS (32.17±4.20 MPa) and a surface more homogeneous and less contaminated were observed in the deproteinization subgruoup compared to the conventional subgroup (27.74±4.88 MPa). AFM parameters were greater in fluorosis subgroup than in healthy enamel subgroup. VM was lower in the fluorotic enamel in each operative step in comparation with healthy enamel. The use of 5% NaOCl as a deproteinizing agent after acid etchant in ground fluorotic enamel results in better adhesion, which may imply greater success in adhesive treatments. The ground surface of fluorotic enamel shows higher values of roughness and depth and lower values of VM which proves that there is a more irregular and less hard surface.

RESUMEN: Evaluar el efecto en la resistencia adhesiva al cizallamiento (SBS) de la aplicación de 5% de NAOCl después del grabado ácido en dientes anteriores fluoróticos tallados y analizar la superficie con microscopía electrónica de barrido (SEM), también comparar esmalte tallado fluorótico y sano por microscopía de fuerza atómica (AFM) y microdureza Vickers (VM). Para la prueba SBS 30 dientes anteriores con fluorosis moderada y severa de acuerdo al índice de Dean fueron seleccionados por un examinador previamente calibrado por un experto en fluorosis usando el coeficiente de correlación intraclase (ICC). La cara vestibular se preparó .3mm con la ayuda de una fresa calibrada para la preparación de carillas y una paralela con punta en chamfer de diamante a alta velocidad e irrigación. En una mitad de la superficie vestibular de los dientes se llevó a cabo el procedimiento adhesivo tradicional, mientras que en la otra mitad se incluyó un paso adicional con la aplicación de NaOCl al 5% por un minute y lavado posterior al grabado ácido. Un poste de resina fué adherido en cada mitad y se aplicó carga hasta la fractura. Se evaluó el modo de fallo y se realizó un análisis con SEM. Posteriormente se utilizaron 10 muestras de esmalte tallado fluorótico y sano para medir las características nano estructurales por medio de AFM (rugosisdad promedio y perfil de profundidad absoluta) y la VM en tres diferentes pasos operativos (posterior al tallado, posterior al grabado ácido y posterior a la desproteinización). Se utilizaron los métodos de Shapiro Wilks y Brown-Forsythe para conocer la distribución de las variables. Una T de student pareada se utilizó para comparar la diferencia entre los promedios de la fuerza de unión (MPa) entre grupos para la prueba SBS. Se llevaron a cabo análisis de chi cuadrada para comparer los modos de fallo entre los grupos. Análisis de ANOVA de una vía y Tukey-Kramer post hoc fueron utilizados para comparar los grupos para las variables rugosidad promedio, perfil de profundidad absoluta y microdureza Vickers. Se observó una mayor SBS (32,17±4,20 MPa) y una superficie más homogénea y menos contaminada en el subgrupo con desproteinización en comparación con el subgrupo convencional (27,74±4,88 MPa). Los parámetros de AFM fueron mayores en el subgrupo de fluorosis que en el subgrupo de esmalte sano. La VM fue más baja en el esmalte fluorótico en cada paso operativo en comparación con el esmalte sano. El uso de NaOCl al 5% como agente desproteinizante después del grabado ácido en el esmalte fluorótico tallado da como resultado una mejor adhesión, lo que puede implicar un mayor éxito en los tratamientos adhesivos. La superficie tallada del esmalte fluorótico muestra valores más altos de rugosidad y profundidad y valores más bajos de VM lo que prueba que existe una superficie más irregular y menos dura.

Identification of Gingival Microcirculation Using Laser Doppler Flowmetry in Patients with Orthodontic Treatment-A Longitudinal Pilot Study.

Background and Objectives: Orthodontic tooth movement is associated with inflammatory responses. The aim of this study was to identify gingival microcirculation using laser Doppler flowmetry in patients with orthodontic treatment. Materials and Methods: A longitudinal pilot study was performed. The participants were selected using a non-probability consecutive sampling. Of the twenty-five subjects, a total of six (four women and two men) complied with the criteria. Before and during the treatment, the oral hygiene index, gingival index, probing depth, level of epithelial attachment, and gingival microcirculation were evaluated with laser Doppler flowmetry (integrated parameters: 1. integrated primary basal flow (IPBF), 2. integrated total secondary real flow (ITSRF), and 3. difference between integration (DBI)) in all of the participants). Results: (a) An increase in gingival blood flow was identified at all time intervals with different arches during orthodontic treatment. (b) The IPBF and ITSRF (with treatment) identified after 20 min (treatment initial stage) were compared with the different time intervals, and we observed an increase in gingival perfusion at the 24th, 48th, and 72nd hours in some arches. (c) In the DBI, we found statistically significant differences (p < 0.005) in the Nitinol group of 0.016 inches among all the time intervals (24 h, 48 h, and 72 h) within the 30-day interval, observing a flow increase three times greater than the basal flow after 30 days. Conclusions: Healthcare professionals must identify the inflammatory processes in treatment to observe and discontinue use of harmful methods in clinical practice.

Should We Be Concerned about the Association of Diabetes Mellitus and Periodontal Disease in the Risk of Infection by SARS-CoV-2? A Systematic Review and Hypothesis.

The objective of this article was to conduct a systematic review of the literature to contrast the existing evidence regarding the relationship between periodontal disease (PD) and diabetes mellitus (DM) with the possibly increased risk of SARS-CoV-2 infection, as well as to establish a hypothesis that explains the ways in which this interaction could take place. A literature search up from 1 January 2020 to 21 March 2021 was conducted in three electronic databases, namely, PubMed, Web of Science, and Scopus, in order to identify studies on periodontal disease alone or in conjunction with diabetes mellitus, reporting any relation with SARS-CoV-2 infection as a primary outcome. Only articles published in the English language were included. Due to the lack of studies, we decided to collect all the theoretical and clinical evidence suggesting a possible biological pathway evidencing the relationship among PD, DM, and SARS-CoV-2 infection. From a total of 29 articles, 12 were included for final review studies (five reviews, two hypotheses, one Special Issue, one perspective, one commentary, one case-control study, and one case report). In addition, this systematic review article hypothesizes the correlation between PD and type 2 diabetes mellitus (T2DM) by expression of angiotensin-converting enzyme 2 (ACE2) in periodontal tissue and the risk of SARS-CoV-2 infection. T2DM is a metabolic disorder characterized by high blood glucose levels resulting from altered insulin secretion or action. Likewise, periodontitis and T2DM are inflammatory disorders with a bidirectional association, and both diseases have a similar immunomodulatory cascade and cytokine profile. ACE2 is a crucial component of the renin-angiotensin system (RAS) and the key factor of entry in the cells by the new SARS-CoV-2. ACE2 is widely distributed in the lung and kidneys, and interestingly has a great distribution in the oral cavity, principally in the tongue and periodontal tissue. ACE2 in periodontal tissue plays a crucial role between health and disease. Moreover, the ACE2/Ang-(1-7)/MasR axis is downregulated in the dysbiotic and inflammatory periodontal environment. Nevertheless, the balance of ACE2 activity is modified in the context of concurrent diabetes, increasing the expression of ACE2 by the uncontrolled glycemia chronic in T2DM. Therefore, the uncontrolled hyperglycemia possibly increases the risk of developing periodontitis and triggering overexpression of ACE2 in periodontal tissue of T2DM patients, with these events potentially being essential to SARS-CoV-2 infection and the development of mild-to-severe form of COVID-19. In this sense, we would like to point out that the need for randomized controlled trials is imperative to support this association.

Presence of SARS-CoV-2 and Its Entry Factors in Oral Tissues and Cells: A Systematic Review.

Background and Objectives: The aim of this systematic review is to summarize the current data about the presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its entry factors in oral tissues and cells. Materials and Methods: This systematic review was carried out based on the Preferred Reporting Items for a Systematic Review and Meta-Analysis (PRISMA). Three databases were analyzed (Pubmed, Web of science and Scopus) by three independent researchers. From the 18 identified studies, 10 of them met the inclusion criteria. The presence of SARS-CoV-2 or its entry factors (angiotensin-converting enzyme II (ACE2), transmembrane serine proteases (TMPRSS), and furin) was analyzed in these 10 studies during the pandemic. Results: ACE2 expression was analyzed in 9 of the 10 studies. ACE2 is expressed mainly in the tongue, oral mucosa, salivary glands and epithelial cells. The expression of the TMPRSS2 gene or protein was analyzed in 6 studies. These studies reported that the expression of TMPRSS2 was mainly in the salivary glands, tongue, sulcular epithelium and oral mucosa; as well as in cells of the salivary glands (ductal, acinar and myoepithelial cells) and the tongue (the spinous-based cell layer, horny layer and the epithelial surface). Other TMPRSS were also reported. The expression of TMPRSS3, TMPRSS4, TMPRSS5, TMPRSS7 and TMPRSS11D was reported mainly in salivary glands and in epithelial-type cells. Furan expression was analyzed in three studies. The expression of furin was detected mainly in epithelial cells of the tongue. A variety of methods were used to carry out the detection of SARS-CoV-2 or its input molecules. Conclusions: These results show that SARS-CoV-2 can infect a wide variety of oral tissues and cells, and that together with the theories dedicated to explaining the oral symptoms present in SARS-CoV-2 positive patients, it provides us with a good scientific basis for understanding the virus infection in the oral cavity and its consequences.

Levels of matrix metalloproteinase-8 and cold test in reversible and irreversible pulpitis.

ABSTRACT: Researchers have reported false positive/negative results of the cold test in the diagnosis of pulpitis. Knowledge of the correlation between results of the cold test and proteins could aid in decreasing the frequency of incorrect diagnosis. To associate the levels of matrix metalloproteinase-8 (MMP-8) with the responses (in seconds) to the cold test in teeth diagnosed with reversible and irreversible pulpitis.A cross-sectional study was performed. A total of 150 subjects were evaluated, of which 60 subjects met the selection criteria. The participants were divided into 3 groups: Group 1, healthy pulps, 20 subjects with 20 posterior teeth (premolars) with clinically normal pulp tissue; Group 2, reversible pulpitis, 20 patients with 20 teeth diagnosed with reversible pulpitis; and Group 3, irreversible pulpitis, 20 subjects with 20 teeth diagnosed with irreversible pulpitis. All participants were evaluated based on the following variables: medical and dental history, cold test, and expression of MMP-8 by enzyme-linked immunosorbent assay in dentin samples.Responses to the cold test between 4 to 5 seconds (second evaluation; P < .0001) were associated with high levels of MMP-8 (mean, 0.36 ng/mL) in the reversible pulpitis group. In the irreversible pulpitis group, the responses from 6 to ≥10 seconds (second evaluation; P < .0001) were associated with a higher average of MMP-8 levels (mean, 1.97 ng/mL).We determined that an increase in the duration of response to the cold test was associated with an increase in MMP-8 levels (Rho = 0.81, P < .0001) in teeth with pulpitis. The above correlations can be considered an adjunct to the clinical diagnosis of pulpitis.

Macrophage migration inhibitory factor gene polymorphisms as exacerbating factors of apical periodontitis.

BACKGROUND: Two polymorphisms in the macrophage migration inhibitory factor (MIF) gene have been associated with inflammatory diseases (-794 CATT5-8 and -173G>C); however, so far there are no reports of studies related to oral health. OBJECTIVES: To genotype the -794 CATT5-8 and -173G>C MIF polymorphisms in Mexican patients with apical periodontitis as a genetic risk of exacerbation. MATERIAL AND METHODS: The study involved 120 patients with apical periodontitis: 60 with a diagnosis of acute apical periodontitis (Group A) and 60 without previous episodes of exacerbation (Group B). Allelic discrimination was performed from peripheral blood DNA; the repeat polymorphism -794 CATT5-8 was genotyped with sequencing, while the -173G>C polymorphism was determined using real-time polymerase chain reaction (RT-PCR) using TaqMan probes. The associations between MIF polymorphisms, haplotypes and the risk of exacerbated apical periodontitis were assessed. RESULTS: The allele CATT7 was associated with the risk of a stage of acute inflammation (OR = 4.13; 95% CI = 1.82-9.63; p =< 0.001). Regarding the -173G >C polymorphism, a process of inflammation exacerbation was only associated with the CC genotype (OR = 4.1; 95% CI = 1.02-20.84; p = 0.045). The analysis of the haplotype showed that the combination CATT7/C increases the risk of exacerbation of apical periodontitis (OR = 3.57; 95% CI = 1.038-13.300; p = 0.021). CONCLUSIONS: The polymorphisms -794 CATT5-8 and -173G>C MIF seem to significantly influence the development of a state of exacerbated inflammation in patients with apical periodontitis.

Expression of calcitonin gene-related peptide and pulp sensitivity tests in irreversible pulpitis.

The aim of the present study was to identify the relationship between the expression of calcitonin gene-related peptide (CGRP) and the responses of pulp sensitivity tests in healthy pulps and irreversible pulps by performing a cross-sectional study on patients. Two hundred subjects were evaluated. A total of 75 subjects complied with the criteria. The participants were divided into two groups: a) Healthy pulp (subjects [n = 35] having posterior teeth with clinically normal pulp tissue), and b) Irreversible pulpitis (subjects [n = 40] having posterior teeth with irreversible pulpitis). All participants were evaluated using the following variables: a) medical and dental history, b) pulp sensitivity tests, c) expression of CGRP by the enzyme-linked immunosorbent assay (ELISA), and d) expression levels of mRNA CGRP and mRNA CGRP receptor genes. We determined that the responses of the cold test between 4 and ≥12 s presented a higher average of the expression of CGRP in the group having irreversible pulpitis (p = 0.0001). When we compared the groups with the value of the electrical impulse, we found statistically significant differences (p = 0.0001), observing positive responses to the test with electrical impulses of 7 to 10, with an average of 72.15 ng/mL of CGRP in the irreversible pulpitis group. High values of CGRP expression were observed in that group in the responses of pulp sensitivity.

Diagnostic accuracy of three placement sites for the cold test in subjects amongst different age groups.

BACKGROUND: The cold test is a specific test of pulp sensitivity and is part of the endodontic diagnosis. The aim of this study was to identify the diagnostic accuracy including sensitivity, specificity, accuracy, positive predictive value and negative predictive value in three sites for the cold test in teeth with a need for endodontic treatment within different age groups from both genders. METHODS: A cross-sectional study was performed, evaluating 425 subjects. Two hundred and fifty-eight subjects from both genders from the ages of 17-27, 28-39, 40-50, and 51-65 years-old participated in the study. The cold test studied was 1, 1, 1, 2-tetrafluoroethane, and the gold standard was established through direct pulp inspection. The sites evaluated in the study were: The sites evaluated in the study were: a) the middle third of the buccal surface; b) the cervical third of the buccal surface, and c) the middle third of the lingual surface. RESULTS: The highest diagnosted accuracy was observed on the middle third buccal surface with an accuracy of = 0.97, a sensitivity of = 1.00, a specificity of 0.95, a predictive value of = 0.95 and a negative predictive value of = 1.00. This was in the female group aged from 40 to 50 years old. CONCLUSION: The tables of this study can be used as an auxiliary for pulp sensitivity tests.

Molecular Mechanisms of Bacterial Resistance to Metal and Metal Oxide Nanoparticles.

The increase in bacterial resistance to one or several antibiotics has become a global health problem. Recently, nanomaterials have become a tool against multidrug-resistant bacteria. The metal and metal oxide nanoparticles are one of the most studied nanomaterials against multidrug-resistant bacteria. Several in vitro studies report that metal nanoparticles have antimicrobial properties against a broad spectrum of bacterial species. However, until recently, the bacterial resistance mechanisms to the bactericidal action of the nanoparticles had not been investigated. Some of the recently reported resistance mechanisms include electrostatic repulsion, ion efflux pumps, expression of extracellular matrices, and the adaptation of biofilms and mutations. The objective of this review is to summarize the recent findings regarding the mechanisms used by bacteria to counteract the antimicrobial effects of nanoparticles.

Expression of calcitonin gene-related peptide and pulp sensitivity tests in irreversible pulpitis

Abstract The aim of the present study was to identify the relationship between the expression of calcitonin gene-related peptide (CGRP) and the responses of pulp sensitivity tests in healthy pulps and irreversible pulps by performing a cross-sectional study on patients. Two hundred subjects were evaluated. A total of 75 subjects complied with the criteria. The participants were divided into two groups: a) Healthy pulp (subjects [n = 35] having posterior teeth with clinically normal pulp tissue), and b) Irreversible pulpitis (subjects [n = 40] having posterior teeth with irreversible pulpitis). All participants were evaluated using the following variables: a) medical and dental history, b) pulp sensitivity tests, c) expression of CGRP by the enzyme-linked immunosorbent assay (ELISA), and d) expression levels of mRNA CGRP and mRNA CGRP receptor genes. We determined that the responses of the cold test between 4 and ≥12 s presented a higher average of the expression of CGRP in the group having irreversible pulpitis (p = 0.0001). When we compared the groups with the value of the electrical impulse, we found statistically significant differences (p = 0.0001), observing positive responses to the test with electrical impulses of 7 to 10, with an average of 72.15 ng/mL of CGRP in the irreversible pulpitis group. High values of CGRP expression were observed in that group in the responses of pulp sensitivity.

Cytotoxic and Bactericidal Effect of Silver Nanoparticles Obtained by Green Synthesis Method Using Annona muricata Aqueous Extract and Functionalized with 5-Fluorouracil.

Nanomaterials obtained by green synthesis technologies have been widely studied in recent years owing to constitute cost-effective and environmental-friendly methods. In addition, there are several works that report the simultaneous performance of the reducer agent as a functionalizing agent, modifying the properties of the nanomaterial. As a simple and economical synthesis methodology, this work presents a method to synthesize silver nanoparticles (AgNPs) using Annona muricata aqueous extract and functionalized with 5-fluorouracil (5-FU). The processes of reduction, nucleation, and functionalization of the nanoparticles were analyzed by UV-Vis absorption spectroscopy, and it was found that they are the function of the contact time of the metal ions with the extract. The structural characterization was carried out by transmission electron microscopy (TEM) and X-ray diffraction patterns (XRD). The antibacterial properties of the synthetized nanomaterials were tested using minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against Enterococcus faecalis, Staphylococcus aureus, and Escherichia coli growth.

In Vitro Synergism of Silver Nanoparticles with Antibiotics as an Alternative Treatment in Multiresistant Uropathogens.

The increase in the prevalence of bacterial resistance to antibiotics has become one of the main health problems worldwide, thus threatening the era of antibiotics most frequently used in the treatment of infections. The need to develop new therapeutic strategies against multidrug resistant microorganisms, such as the combination of selected antimicrobials, can be considered as a suitable alternative. The in vitro activities of two groups of conventional antimicrobial agents alone and in combination with silver nanoparticles (AgNPs) were investigated against a set of ten multidrug resistant clinical isolate and two references strains by MIC assays and checkerboard testing, as well as their cytotoxicity, which was evaluated on human fibroblasts by MTT assay at the same concentration of the antimicrobial agents alone and in combination. Interesting results were achieved when the AgNPs and their combinations were characterized by Dynamic Light Scattering (DLS), Zeta Potential, Transmission Electron Microscopy (TEM), UV⁻visible spectroscopy and Fourier Transforms Infrared (FTIR) spectroscopy. The in vitro activities of ampicillin, in combination with AgNPs, against the 12 microorganisms showed one Synergy, seven Partial Synergy and four Additive effects, while the results with amikacin and AgNPs showed three Synergy, eight Partial Synergy and one Additive effects. The cytotoxic effect at these concentrations presented a statistically significant decrease of their cytotoxicity (p < 0.05). These results indicate that infections caused by multidrug resistant microorganisms could be treated using a synergistic combination of antimicrobial drugs and AgNPs. Further studies are necessary to evaluate the specific mechanisms of action, which could help predict undesirable off-target interactions, suggest ways of regulating a drug’s activity, and identify novel therapeutic agents in this health problem.

Identification of the Most Appropriate Site for the Cold Test in Molar Teeth / Identificación del sitio más apropiado para la prueba de frío en dientes molares

Abstract A test frequently used to complement endodontic diagnoses is the cold test; however, in the last 20 years, authors have reported incorrect results within pulp sensitivity tests. Specifically, a high frequency of false results in posterior teeth, were found. The aim of this study was to identify the most appropriate site for the cold test in molar teeth with a need for endodontic treatment, calculating predictive values, accuracy and reproducibility. A cross-sectional study was performed, evaluating 390 subjects. A total of 152 subjects of both genders from the ages of 15-65 years old participated. The ideal standard was established by direct pulp inspection, and the cold test agent used was 1,1,1,2-tetrafluoroethane. The patients were divided into four groups in relation to the molar tooth: (1) mandibular first molar, (2) mandibular second molar, (3) maxillary first molar, and (4) maxillary second molar. 169 teeth and 676 sites were studied. (a) The most appropriate sites for cold test were the middle third of the buccal surface and cervical third of the buccal surface in the mandibular molars with the following results: Middle third of the first molar: Accuracy 0.93, positive predictive value 0.90 and negative predictive value 0.96. Middle third of the second molar: Accuracy 0.93, positive predictive value 1.00 and negative predictive value 0.90. In relation to third cervical the results were: First molar: Accuracy 0.93, positive predictive value 0.89 and negative predictive value 0.97 y second molar: Accuracy 0.93, positive predictive value 1.00 and negative predictive value 0.90. (b) The highest reproducibility was observed in the middle third of the buccal surface with cervical third of the buccal surface in the mandibular second molar (1.00). The most appropriate site and reproducibility of the sites are auxiliary to complement endodontic diagnose with the cold test.

Resumen Una prueba frecuentemente utilizada para complementar los diagnósticos endodónticos es la prueba de frío. Sin embargo, en los últimos 20 años, los autores han reportado resultados incorrectos con las pruebas de sensibilidad pulpar. Específicamente, se ha observado una alta frecuencia de resultados falsos en dientes posteriores. El objetivo del estudio fue identificar el sitio más adecuado para la prueba de frío en dientes molares con necesidad de tratamiento endodóntico, calculando valores predictivos, exactitud y reproducibilidad. Se realizó un estudio transversal donde se evaluaron a 390 sujetos. 152 sujetos de ambos sexos de 15 a 65 años cumplieron con los criterios de inclusión. El estándar ideal que se utilizó en el estudio fue la inspección directa de pulpa en la cámara pulpar y la prueba de frío utilizada fue el 1,1,1,2-tetrafluoroetano. Los pacientes fueron divididos en cuatro grupos en relación al diente molar: (1) primer molar mandibular, (2) segundo molar mandibular, (3) primer molar maxilar, y (4) segundo molar maxilar. En el estudio se evaluaron 169 dientes con 676 sitios. (a) Los sitios más adecuados para la prueba de frío fueron el tercio medio y el tercio cervical de la superficie bucal en los molares mandibulares con los siguientes resultados: Tercio medio del primer molar: Exactitud 0.93, valor predictivo positivo 0.90 y valor predictivo negativo 0.96. Tercio medio del segundo molar: Exactitud 0.93, valor predictivo positivo 1.00 y valor predictivo negativo 0.90. En relación al tercio cervical los resultados fueron: Primer molar: Exactitud 0.93, valor predictivo positivo 0.89 y valor predictivo negativo 0,97 y segundo molar: Exactitud 0.93, valor predictivo positivo 1.00 y valor predictivo negativo 0.90. (b) La más alta reproducibilidad (1.00) se observó entre el tercio medio con el tercio cervical de la superficie bucal en el segundo molar inferior. El sitio más apropiado y la reproducibilidad de los sitios son auxiliares para complementar el diagnóstico endodóntico con la prueba de frío.

Evaluation of cardiovascular responses to silver nanoparticles (AgNPs) in spontaneously hypertensive rats.

Silver nanoparticles (AgNPs) are used in the medical, pharmaceutical and food industry. Adverse effects and toxicity induced by AgNPs upon cardiac function related to nitric oxide (NO) and oxidative stress (OS) are described. AgNPs-toxicity may be influenced by cardiovascular pathologies such as hypertension. However, the molecules involved under pathophysiological conditions are not well studied. The aim of this work was to evaluate perfusion pressure (PP) and left ventricle pressure (LVP) as physiological parameters of cardiovascular function in response to AgNPs, using isolated perfused hearts from spontaneously hypertensive rats (SHR), and identify the role of NO and OS. The results suggest that AgNPs reduced NO derived from endothelial/inducible NO-synthase and increased OS, leading to increased and sustained vasoconstriction and myocardial contractility. Additionally, the hypertension condition alters phenylephrine (Phe) and acetylcholine (ACh) classic effects. These data suggest that hypertension intensified AgNPs-cardiotoxicity. Nevertheless, the precise mechanism of action is still under elucidation.