Comparative Evaluation of Sealing Ability of Three Different Materials as Barriers to Coronal Microleakage in Root-Filled Teeth: An In Vitro Study.

Aim: To compare the sealing ability of three different materials when used as postendodontic restoration barriers to coronal microleakage in root-filled teeth. Materials and Methods: In the present study, 60 single-rooted mandibular premolars with single canals were selected. After endodontic treatment was done with protaper files, they were divided into three groups of 20 teeth each, which were restored with Zirconomer (Group I), Hi-Dense (Group II), and Surefil composite (Group III), respectively. After storing in artificial saliva for 10 days, all teeth were then immersed in Rhodamine 6G fluorescent dye. Teeth were then sectioned buccolingually in a longitudinal direction. The coronal microleakage was measured in both halves under a fluorescence microscope and images were taken with a digital camera. Data obtained from the study in the form of scoring as per specific criteria was subjected to statistical analysis. Result: Results of the study showed that the minimum amount of coronal microleakage was seen in Group II restored with Hi-Dense followed by Group III restored with Surefil Composite and the maximum amount of coronal microleakage was seen in Group I restored with Zirconomer. Conclusion: On the basis of the results of the present study, it may be concluded that Hi-Dense showed better coronal sealing ability in access cavities. Surefil composite exhibited coronal microleakage less than Zirconomer but more than Hi-Dense.

Attenuation of Las/Rhl quorum sensing regulated virulence and biofilm formation in Pseudomonas aeruginosa PAO1 by Artocarpesin.

The emergence of multidrug resistance and increased pathogenicity in microorganisms is conferred by the presence of highly synchronized cell density dependent signalling pathway known as quorum sensing (QS). The QS hierarchy is accountable for the secretion of virulence phenotypes, biofilm formation and drug resistance. Hence, targeting the QS phenomenon could be a promising strategy to counteract the bacterial virulence and drug resistance. In the present study, artocarpesin (ACN), a 6-prenylated flavone was investigated for its capability to quench the synthesis of QS regulated virulence factors. From the results, ACN showed significant inhibition of secreted virulence phenotypes such as pyocyanin (80%), rhamnolipid (79%), protease (69%), elastase (84%), alginate (88%) and biofilm formation (88%) in opportunistic pathogen, Pseudomonas aeruginosa PAO1. Further, microscopic observation of biofilm confirmed a significant reduction in biofilm matrix when P. aeruginosa PAO1 was supplemented with ACN at its sub-MIC concentration. Quantitative gene expression studies showed the promising aspects of ACN in down regulation of several QS regulatory genes associated with production of virulence phenotypes. Upon treatment with sub-MIC of ACN, the bacterial colonization in the gut of Caenorhabditis elegans was potentially reduced and the survival rate was greatly improved. The promising QS inhibition activities were further validated through in silico studies, which put an insight into the mechanism of QS inhibition. Thus, ACN could be considered as possible drug candidate targeting chronic microbial infections.

Evaluation of Anxiety Levels in Children While Using Rubber Dam and OptraDam Isolation Techniques.

Aim: The aim of the study was to evaluate the anxiety levels in children while using rubber dam and OptraDam isolation techniques. Materials and methods: This study was a crossover trial conducted on 27 selected 6-12-year-old children. The procedure of placement of either of the isolation techniques was told and demonstrated using audiovisual aid. The sequence of the proceedings on each child (rubber dam or OptraDam) was determined randomly using toss of coin. Second demonstration was carried out 7 days after the first demonstration. The anxiety experienced was recorded using Venham's anxiety scale at two time points-after verbal explanation and after the audiovisual demonstration. The study also objectively assessed the anxiety by measuring the salivary malondialdehyde (MDA) levels of two patients. Results: When mean values of Venham's anxiety scores after verbal explanation and after audiovisual demonstration were compared for each of the two techniques using paired Student's t test, there was statistically significant decrease in the anxiety score following audiovisual demonstration in both the techniques. When the scores between two groups after verbal explanation and after audiovisual demonstration were compared using repeated measures of analysis of variance (ANOVA), the reported anxiety scores were significantly lesser for the OptraDam technique (p = 0.000). Conclusion: Audiovisual demonstration reduced the anxiety of children when compared to verbal explanation for both isolation techniques. OptraDam isolation was found to be less anxiety generating in children compared to rubber dam isolation. Clinical significance: When using modern adhesive techniques, a good isolation of the working field is an important requirement for better prognosis. OptraDam being the latest addition to the rubber dam family, if found to be more children friendly can solve majority of the problems related to isolation in pediatric dentistry. How to cite this article: S Mahima, YM Karuna, Shenoy R, et al. Evaluation of Anxiety Levels in Children while using Rubber Dam and OptraDam Isolation Techniques. Int J Clin Pediatr Dent 2023;16(2):287-291.

Surveillance and mitigation of soil pollution through metagenomic approaches.

Soil pollution is one of the serious global threats causing risk to environment and humans. The major cause of accumulation of pollutants in soil are anthropogenic activities and some natural processes. There are several types of soil pollutants which deteriorate the quality of human life and animal health. They are recalcitrant hydrocarbon compounds, metals, antibiotics, persistent organic compounds, pesticides and different kinds of plastics. Due to the detrimental properties of pollutants present in soil on human life and ecosystem such as carcinogenic, genotoxic and mutagenic effects, alternate and effective methods to degrade the pollutants are recommended. Bioremediation is an effective and inexpensive method of biological degradation of pollutants using plants, microorganisms and fungi. With the advent of new detection methods, the identification and degradation of soil pollutants in different ecosystems were made easy. Metagenomic approaches are a boon for the identification of unculturable microorganisms and to explore the vast bioremediation potential for different pollutants. Metagenomics is a power tool to study the microbial load in polluted or contaminated land and its role in bioremediation. In addition, the negative ecosystem and health effect of pathogens, antibiotic and metal resistant genes found in the polluted area can be studied. Also, the identification of novel compounds/genes/proteins involved in the biotechnology and sustainable agriculture practices can be performed with the integration of metagenomics.

Soil carries diverse microorganisms which maintain plant and soil health.The different types of recalcitrant soil pollutants affect the ecosystem and human health.Complex pollutants can be degraded through bioremediation using microorganisms/plantsMetagenomic approaches help to explore novel organisms and enzymes involved in bioremediation.

Polymicrobial Infections and Biofilms: Clinical Significance and Eradication Strategies.

Biofilms are population of cells growing in a coordinated manner and exhibiting resistance towards hostile environments. The infections associated with biofilms are difficult to control owing to the chronicity of infections and the emergence of antibiotic resistance. Most microbial infections are contributed by polymicrobial or mixed species interactions, such as those observed in chronic wound infections, otitis media, dental caries, and cystic fibrosis. This review focuses on the polymicrobial interactions among bacterial-bacterial, bacterial-fungal, and fungal-fungal aggregations based on in vitro and in vivo models and different therapeutic interventions available for polymicrobial biofilms. Deciphering the mechanisms of polymicrobial interactions and microbial diversity in chronic infections is very helpful in anti-microbial research. Together, we have discussed the role of metagenomic approaches in studying polymicrobial biofilms. The outstanding progress made in polymicrobial research, especially the model systems and application of metagenomics for detecting, preventing, and controlling infections, are reviewed.

Patent foramen ovale: diagnostic evaluation and the role of device closure.

Although seemingly benign, the presence of a patent foramen ovale (PFO) may play an important role in the pathophysiology of disease, specifically a paradoxical embolism leading to cryptogenic stroke. The European Society of Cardiology recently published guidelines detailing how PFOs are associated with paradoxical embolism and how they are diagnosed and managed. This review guides physicians in the diagnostic and referral process to a multidisciplinary team involved in PFO closure. It reviews the clinical trials comparing device closure with medical therapy and highlights the current NHS England commissioning process on PFO management. Finally, we give an overview of other conditions where PFO device closure may need to be considered.

Metagenomic insights into taxonomic, functional diversity and inhibitors of microbial biofilms.

Microbial cells attached to inert or living surfaces adopt biofilm mode with self-produced exopolysaccharide matrix containing polysaccharides, proteins, and extracellular DNA, for protection from adverse external stimuli. Biofilms in hospitals and industries serve as a breeding ground for drug-resistant pathogens and ARG enrichment that are linked to pathogenicity and also impede industrial production process. Biofilm formation, including virulence and pathogenicity, is regulated through quorum sensing (QS), a means of bacterial cell to cell communication for cooperative physiological processes. Hence, QS inhibition through quorum quenching (QQ) is a feasible approach to inhibit biofilm formation. In contrast, biofilms have beneficial roles in promoting plant growth, biocontrol, and wastewater treatment. Furthermore, polymicrobial biofilms can harbour novel compounds and species of industrial and pharmaceutical interest. Hence, surveillance of biofilm microbiome structure and functional attributes is crucial to determine the extent of the risk it poses and to harness its bioactive potential. One of the most preferred approaches to delineate the microbiome is culture-independent metagenomics. In this context, this review article explores the biofilm microbiome in built and natural settings such as agriculture, household appliances, wastewater treatment plants, hospitals, microplastics, and dental biofilm. We have also discussed the recent reports on discoveries of novel QS and biofilm inhibitors through conventional, metagenomics, and machine learning approaches. Finally, we present biofilm-derived novel metagenome-assembled genomes (MAGs), genomes, and taxa of medical and industrial interest.

Multiple cell types contribute to the atherosclerotic lesion fibrous cap by PDGFRß and bioenergetic mechanisms.

Stable atherosclerotic plaques are characterized by a thick, extracellular matrix-rich fibrous cap populated by protective ACTA2+ myofibroblast (MF)-like cells, assumed to be almost exclusively derived from smooth muscle cells (SMCs). Herein, we show that in murine and human lesions, 20% to 40% of ACTA2+ fibrous cap cells, respectively, are derived from non-SMC sources, including endothelial cells (ECs) or macrophages that have undergone an endothelial-to-mesenchymal transition (EndoMT) or a macrophage-to-mesenchymal transition (MMT). In addition, we show that SMC-specific knockout of the Pdgfrb gene, which encodes platelet-derived growth factor receptor beta (PDGFRß), in Apoe-/- mice fed a Western diet for 18 weeks resulted in brachiocephalic artery lesions nearly devoid of SMCs but with no changes in lesion size, remodelling or indices of stability, including the percentage of ACTA2+ fibrous cap cells. However, prolonged Western diet feeding of SMC Pdgfrb-knockout mice resulted in reduced indices of stability, indicating that EndoMT- and MMT-derived MFs cannot compensate indefinitely for loss of SMC-derived MFs. Using single-cell and bulk RNA-sequencing analyses of the brachiocephalic artery region and in vitro models, we provide evidence that SMC-to-MF transitions are induced by PDGF and transforming growth factor-ß and dependent on aerobic glycolysis, while EndoMT is induced by interleukin-1ß and transforming growth factor-ß. Together, we provide evidence that the ACTA2+ fibrous cap originates from a tapestry of cell types, which transition to an MF-like state through distinct signalling pathways that are either dependent on or associated with extensive metabolic reprogramming.

Dendrimers: General Aspects, Applications and Structural Exploitations as Prodrug/Drug-delivery Vehicles in Current Medicine.

Dendrimers are hyper branched macro molecules with well-defined structure and high degree of functionality on the surface. The dendrimer architecture allows control over properties such as shape, size, density, polarity, reactivity, solubility etc. These special features can be exploited to design molecules having desired properties used for biomedical applications. Recent advancements in correlation between structure and biodegradability and in vivo performance are opening up new avenues for these molecules; particularly, in biological applications like drug delivery. The unique structure of dendrimers provides enough attachment sites for drugs. Further, it is possible to tune the molecules in such a way so that the drug molecules are encapsulated outside the target area and are released only in the local environment of targets. This review presents some general aspects of dendrimers and how their properties are exploited for drug delivery applications.

Role of polyfunctional organic molecules in the synthesis and assembly of metal nanoparticles.

The role of polyfunctional organic molecules in the synthesis of differently shaped metallic nanostructures and their assembly is investigated. These molecules could be used as spacer ligands and also for surface passivation of nanoparticles, especially with the objective of controlling their electronic and optical properties depending on their length scales. We investigate the role of several such molecules, such as 4-aminothiophenol, tridecylamine, Bismarck brown R and Y, mordant brown, fat brown, chrysoidin (basic orange), and 3-aminobenzoic acid in the synthesis and assembly of various nanoparticles of gold and silver. For example, the use of 4-ATP helps in the formation of rod shaped micelles in aqueous acetonitrile as confirmed by transmission electron microscopy (TEM) suggesting their role as soft templates. In addition, 4-ATP has also been used for the formation of heteroassembly of spherical nanoparticles of gold and silver at controlled pH. Significantly, triangular and hexagonal gold nanoplates are formed at room temperature by similar polyfunctional dye molecule, Bismarck brown R (BBR), while other analogous dye molecules give only arbitrary shaped gold nanoparticles. Further confirmation of their role in shape determination comes from linear amine molecules such as tridecylamine, which give only spherical nanoparticles both for silver and gold. In essence, our study confirms the role of various such organic molecules in shape controlled synthesis of nanoparticles. We also report optical and electrochemical properties of few of these nanostructures as a function of their shape.

Electrochemical organization of monolayer protected gold nanoclusters on single-walled carbon nanotubes: significantly enhanced double layer capacitance.

This paper reports a novel electrochemical route for anchoring monolayer protected gold nanoclusters (size 8 +/- 0.2 nm) on single-walled carbon nanotube bundles, resulting in the formation of hybrid materials. Monolayer protected gold nanoclusters prepared by modified Brust synthesis route were organized on SWNT bundles by cycling the potential in dichloromethane between -1 to +1 V at a scan rate of 50 mV/s. Monolayer protected nanoclusters in electrolyte solutions possess ionic space charge around them (double layer charging), making them suitable for organization on nanotube bundles, by tuning the electrostatic interactions. More significantly, analysis of the double layer capacitance of these hybrid materials shows almost ten times increase in capacitance compared to that of bare SWNT bundles. We believe that these hybrid materials are potentially useful in nanoelectronics.

Light-induced modulation of self-assembly on spiropyran-capped gold nanoparticles: a potential system for the controlled release of amino acid derivatives.

A photoswitchable double-shell structure on Au nanoparticles, consisting of photochromic spiropyran as the first shell, which regulates the assembly and release of an outer shell of amino acid derivatives upon irradiation, is being reported for the first time. The light-regulated changes in the topographic properties of spiropyran-capped Au nanoparticles (i.e., interconversion between the zwitterionic and neutral forms) are exploited for the assembly and release of amino acid-based therapeutic agents such as l-DOPA.