SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: Pulp

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Endodontic sealer residues remaining within the pulp chamber dentin after root canal obturation and cleaning with various solvents may compromise the appearance and the durability of dental restorations. Acid etching is routinely performed prior to application of dentine adhesive systems, but is effect on residual sealer material and the optimal time-point for performing etching, are unknown. Here, we evaluated the effect of acid etching on the dentin surface when performed either immediately or 7 days after removal of the endodontic sealer with two solvents, i.e., 95% ethanol or xylol. Forty crowns fragments from bovine incisors were impregnated with sealer and divided into 4 groups (n = 10 each), according to the dentin cleaning protocol and to the acid etching time-point: G1, 95.0% ethanol and immediate acid etching; G2, xylol and immediate acid etching; G3, 95.0% ethanol and acid etching after 7 days; and G4, xylol and acid etching after 7 days. Scanning electron microscopy (SEM) images (2000 ×) were obtained from each specimen and the number of open dentinal tubules counted and compared. Another 40 fragments were similarly prepared, and SEM images were obtained (500 ×) to score and compare the persistence of sealer residues on the dentin. G4 showed the most open dentinal tubules and the least epoxy resin-based sealer residues on the dentin surface (p < 0.05). The least epoxy resin-based sealer residues was obtained when acid etching, using 37% phosphoric acid, was performed after 7 days after cleaning the dentin with xylol.

Concepts: Acid, Ethanol, Phosphoric acid, Teeth, Dental caries, Scanning electron microscope, Dentin, Pulp

27

To investigate the cytotoxicity of BioAggregate and iRoot BP Plus root canal sealer (iRoot BP Plus) to human dental pulp cells (hDPCs) and their effect on proliferation and mineralization of hDPCs and to compare their performance with that of mineral trioxide aggregate (MTA).

Concepts: Dietary mineral, Mineral, Teeth, Endodontic therapy, Dentin, Pulp

27

Dental pulp inflammation and repair are closely related. Osteocalcin (OCN), a glycoprotein present in dentin matrix, is expressed by odontoblasts. Although OCN is considered a reparative molecule inside the dental pulp, it is not clear if it is involved in pulpal inflammation. The objective of this study was to localize OCN in reversible and irreversible pulpitis and to describe its possible function in inflammation.

Concepts: Gene expression, Teeth, Dental caries, Dentin, Expression, Pulp, Odontoblast, Dentinogenesis

27

The goal of this study was to examine the adhesive interface of pulp tissue to investigate subclinical failures after direct pulp capping (DPC) of human teeth by using a dentin adhesive system.

Concepts: Teeth, Tooth, Dentin, Pulp, Odontoblast

27

The aim of this study was to investigate the role of the steroid fluocinolone acetonide on the proliferation and mineralization of human dental pulp cells (DPCs). The potential effect of fluocinolone acetonide on reparative dentin formation and the recovery of injured dental pulp were evaluated.

Concepts: Corticosteroid, Teeth, Dental caries, Dentin, Pulp, Odontoblast, Fluocinolone acetonide, Dentinogenesis

24

Continuous-flow nanocatalysis by metal nanoparticle (NP) catalyst-anchored flow reactors has recently provided an excellent platform for effective chemical manufacturing. However, there has been limited progress in porous structure design and recycling systems for metal NP-anchored flow reactors to create more efficient and sustainable catalytic processes. Here, we renovated traditional paper as an efficient, recyclable, and renewable flow reactor by tailoring the ultra-structures of wood pulp. The ‘paper reactor’ offers hierarchically interconnected micro/nanoscale pores for efficient access of reactants to catalysts. In continuous-flow catalytic reduction of 4-nitrophenol, a gold NP-anchored paper reactor with the tailored micro/nanopores provided higher reaction efficiency than state-of-the-art flow reactors. Successful recycling and renewing of the paper reactors were also demonstrated. Our strategy offers potential for highly efficient and truly sustainable chemical manufacturing.

Concepts: Chemical reaction, Structure, Hydrogen, Nitrogen, Paper, Wood, Pulp, Paperboard

5

This is the first time a 100% natural, unmodified nanofibrous polymer-based membrane is demonstrated capable of removing viruses solely based on the size-exclusion principle, with log10 reduction value (LRV) ≥ 6.3 as limited by the assay lower detection limit and the feed virus titre, thereby matching the performance of industrial synthetic polymer virus removal filters.

Concepts: DNA, Protein, Life, Analytical chemistry, Paper, Filters, Pulp, Filter paper

4

The integration of smartphone with paper sensors recently has been gain increasing attentions because of the achievement of quantitative and rapid analysis. However, smartphone based upconversional paper sensors have been restricted by the lack of effective methods to acquire luminescence signals on test paper. Herein, by the virtue of 3D printing technology, we exploited an auxiliary reusable device, which orderly assembled a 980nm mini-laser, optical filter and mini-cavity together, for digitally imaging the luminescence variations on test paper and quantitative analyzing pesticide thiram by smartphone. In detail, copper ions decorated NaYF4:Yb/Tm upconversion nanoparticles were fixed onto filter paper to form test paper, and the blue luminescence on it would be quenched after additions of thiram through luminescence resonance energy transfer mechanism. These variations could be monitored by the smartphone camera, and then the blue channel intensities of obtained colored images were calculated to quantify amounts of thiram through a self-written Android program installed on the smartphone, offering a reliable and accurate detection limit of 0.1μM for the system. This work provides an initial demonstration of integrating upconversion nanosensors with smartphone digital imaging for point-of-care analysis on a paper-based platform.

Concepts: Measurement, Signal processing, Integral, Digital photography, Paper, Filter, Pulp, Filter paper

2

Lignin is a potential biorefinery feedstock for the production of value-added chemicals including vanillin. A huge amount of lignin is produced as a by-product of the paper industry, while cellulosic components of plant biomass are utilized for the production of paper pulp. In spite of vast potential, lignin remains the least exploited component of plant biomass due to its extremely complex and heterogenous structure. Several enzymes have been reported to have lignin-degrading properties and could be potentially used in lignin biorefining if their catalytic properties could be improved by enzyme engineering. The much needed improvement of lignin-degrading enzymes by high-throughput selection techniques such as directed evolution is currently limited, as robust methods for detecting the conversion of lignin to desired small molecules are not available.

Concepts: Bacteria, Metabolism, Enzyme, Fungus, Catalysis, Cellulose, Pulp, Biomass

1

Pulpal revascularization is commonly used in the dental clinic to obtain apical closure of immature permanent teeth with thin dentinal walls. Although sometimes successful, stimulating bleeding from the periapical area of the tooth can be challenging and in turn may deleteriously affect tooth root maturation. Our objective here was to define reliable methods to regenerate pulp-like tissues in tooth root segments (RSs). G1 RSs were injected with human dental pulp stem cells (hDPSCs) and human umbilical vein endothelial cells (HUVECs) encapsulated in 5% gelatin methacrylate (GelMA) hydrogel. G2 RSs injected with acellular GelMA alone, and G3 empty RSs were used as controls. White mineral trioxide aggregate was used to seal one end of the tooth root segment, while the other was left open. Samples were cultured in vitro in osteogenic media (OM) for 13 d and then implanted subcutaneously in nude rats for 4 and 8 wk. At least 5 sample replicates were used for each experimental group. Analyses of harvested samples found that robust pulp-like tissues formed in G1, GelMA encapsulated hDPSC/HUVEC-filled RSs, and less cellularized host cell-derived pulp-like tissue was observed in the G2 acellular GelMA and G3 empty RS groups. Of importance, only the G1, hDPSC/HUVEC-encapsulated GelMA constructs formed pulp cells that attached to the inner dentin surface of the RS and infiltrated into the dentin tubules. Immunofluorescent (IF) histochemical analysis showed that GelMA supported hDPSC/HUVEC cell attachment and proliferation and also provided attachment for infiltrating host cells. Human cell-seeded GelMA hydrogels promoted the establishment of well-organized neovasculature formation. In contrast, acellular GelMA and empty RS constructs supported the formation of less organized host-derived vasculature formation. Together, these results identify GelMA hydrogel combined with hDPSC/HUVECs as a promising new clinically relevant pulpal revascularization treatment to regenerate human dental pulp tissues.

Concepts: Tissues, Umbilical vein, Cardiovascular system, Teeth, Dentin, Dentistry, Pulp, Odontoblast