An innovative Fuller's earth-based film-forming formulation for skin decontamination, through removal and entrapment of an organophosphorus compound, paraoxon-ethyl.

Organophosphorus compounds (OPs), such as VX, pose a significant threat due to their neurotoxic and hazardous properties. Skin decontamination is essential to avoid irreversible effects. Fuller's earth (FE), a phyllosilicate conventionally employed in powder form, has demonstrated decontamination capacity against OPs. The aim of this study was to develop a formulation that forms a film on the skin, with a significant OP removal capacity (>95 %) coupled with sequestration capabilities, favorable drying time and mechanical properties to allow for easy application and removal, particularly in emergency context. Various formulations were prepared using different concentrations of polyvinyl alcohol (PVA), FE and surfactants. Their removal and sequestration capacity was tested using paraoxon-ethyl (POX), a chemical that simulates the behavior of VX. Formulations with removal capacity levels surpassing 95 % were mechanically characterized and cell viability assays were performed on Normal Human Dermal Fibroblast (NHDF). The four most promising formulations were used to assess decontamination efficacy on pig ear skin explants. These formulations showed decontamination levels ranging from 84.4 ± 4.7 % to 96.5 ± 1.3 %, which is equivalent to current decontamination methods. These results suggest that this technology could be a novel and effective tool for skin decontamination following exposure to OPs.

Examination of surface porosity of current pulp capping materials by micro-computed tomography (micro-CT) method.

When dental pulp is exposed, it must be covered with a biocompatible material to form reparative dentine. The material used, besides being biocompatible, should have an ideal surface structure for the attachment, proliferation and differentiation of dental pulp stem cells. This study aimed to evaluate the porosity of the microstructures of four pulp capping materials using micro-computed tomography (micro-CT). Biodentine, Bioaggregate, TheraCal and Dycal materials were prepared according to the manufacturer's instructions using 2 × 9 mm Teflon molds. A total of 60 samples, 15 in each group, were scanned using micro-CT. Open and closed pores and the total porosity of the microstructures of the materials were assessed. The findings obtained from the study were analyzed via the Kruskal-Wallis test followed by the Mann-Whitney U test. The porosity of Bioaggregate was significantly higher than that of Biodentine, Dycal and TheraCal in all porosity values. While Biodentine did not show a statistically significant difference in open and total porosity values from either TheraCal or Dycal, closed porosity values of Dycal were significantly higher than those of Biodentine and TheraCal. Because of the affinity of cells to porous surfaces, the pulp capping materials' microstructure may affect the pulp capping treatment's success. From this perspective, the use of Bioaggregate in direct pulp capping may increase the success of treatment.

The effect of three additives on properties of mineral trioxide aggregate cements: a systematic review and meta-analysis of in vitro studies.

BACKGROUND: Several efforts have been made to improve mechanical and biological properties of calcium silicate-based cements through changes in chemical composition of the materials. This study aimed to investigate the physical (including setting time and compressive strength) and chemical (including calcium ion release, pH level) properties as well as changes in cytotoxicity of mineral trioxide aggregate (MTA) after the addition of 3 substances including CaCl2, Na2HPO4, and propylene glycol (PG). METHODS: The systematic review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Electronic searches were performed on PubMed, Embase, and Scopus databases, spanning from 1993 to October 2023 in addition to manual searches. Relevant laboratory studies were included. The quality of the included studies was assessed using modified ARRIVE criteria. Meta-analyses were performed by RevMan statistical software. RESULTS: From the total of 267 studies, 24 articles were included in this review. The results of the meta-analysis indicated that addition of PG increased final setting time and Ca2+ ion release. Addition of Na2HPO4 did not change pH and cytotoxicity but reduced the final setting time. Incorporation of 5% CaCl2 reduced the setting time but did not alter the cytotoxicity of the cement. However, addition of 10% CaCl2 reduced cell viability, setting time, and compressive strength. CONCLUSION: Inclusion of 2.5% wt. Na2HPO4 and 5% CaCl2 in MTA can be advisable for enhancing the physical, chemical, and cytotoxic characteristics of the admixture. Conversely, caution is advised against incorporating elevated concentrations of PG due to its retarding effect. TRIAL REGISTRATION: PROSPERO registration number: CRD42021253707.

Comparative Evaluation of Push-out Bond Strength of Conventional Mineral Trioxide Aggregate, Biodentine, and Two Novel Antibacterial-enhanced Mineral Trioxide Aggregates.

AIM: To evaluate the push-out bond strength of two newly modified mineral trioxide aggregates (MTAs) with conventional MTA and biodentine. MATERIALS AND METHODS: Material preparation: Two commercially available bioactive bioceramics: Group I: Mineral trioxide aggregate; Group II: Biodentine; and two newly formulated modified MTAs: Group III: Doxycycline incorporated MTA formulation; Group IV: Metronidazole incorporated MTA formulation was used in the present study. All the test materials were then carried using a plastic instrument to the desired experimental design. Teeth sample preparation: A total of 120 teeth samples were collected and divided into four groups of test materials with 30 teeth samples per group. Single-rooted permanent teeth, that is, incisors were collected and stored in saline until the study was performed. Sectioning of the teeth into 2.0 ± 0.05-mm thick slices was performed perpendicular to the long axis of the tooth. The canal space was instrumented using Gates Glidden burs to achieve a diameter of 1.5 mm. All four prepared materials were mixed and placed in the lumen of the slices and placed in an incubator at 37°C for 72 hours. Push-out test and bond failure pattern evaluation: The push-out test was performed using a universal testing machine. The slices were examined under a scanning electron microscope (SEM) at 40× magnification to determine the nature of bond failure. All the collected data were recorded and statistically analyzed. RESULTS: The mean push-out bond strength was found to be the highest for group II (37.38 ± 1.94 MPa) followed by group III (28.04 ± 2.22 MPa) and group IV (27.83 ± 1.34 MPa). The lowest mean push-out bond strength was noticed with group I (22.89 ± 2.49 MPa). This difference was found to be statistically significant (p = 0.000). Group I samples had the predominantly adhesive type of failure (86.4%), while group II samples showed the cohesive type of failure (94.2%). Both the modified MTAs (groups III and IV) primarily showed mixed types of failures. CONCLUSION: Both the antibacterial-enhanced MTAs had better pushout bond strength compared to conventional MTA but did not outperform biodentine. Hence, it could serve as a substitute for conventional MTA due to its augmented physical properties. CLINICAL SIGNIFICANCE: Carious pulp exposure and nonvital open apices pose a critical challenge to pediatric dental practitioners. In such circumstances, maintaining the vitality of pulp and faster healing would help in a better prognosis. Novel MTAs without any cytotoxic components, and enhanced antibacterial contents with augmented physical properties can help in treating such clinical conditions. How to cite this article: Merlin ARS, Ravindran V, Jeevanandan G, et al. Comparative Evaluation of Push-out Bond Strength of Conventional Mineral Trioxide Aggregate, Biodentine, and Two Novel Antibacterial-enhanced Mineral Trioxide Aggregates. J Contemp Dent Pract 2024;25(2):168-173.

Biocompatibility and Bioactivity of a Dual-Cured Resin-Based Calcium Silicate Cement: In Vitro and in vivo Evaluation.

INTRODUCTION: This study aimed to assess the biocompatibility and bioactivity of a dual-cured resin-based calcium silicate cement in vitro and in vivo. METHODS: For in vitro analyses, standardized samples were prepared using TheraCal LC, TheraCal PT, and ProRoot MTA. The amount of residual monomer released from TheraCal LC and TheraCal PT was assessed using liquid chromatography/mass spectrometry. Calcium ion release from the materials was evaluated using inductively coupled plasma-optical emission spectroscopy. Scanning electron microscopy and energy-dispersive X-ray spectroscopy were used to determine the calcium weight volume in the materials. For in vivo analysis, a rat direct pulp capping model with TheraCal LC, TheraCal PT, and ProRoot MTA groups (n = 16 per group) was used. The rats were euthanized after 7 or 28 days, and histological and immunohistochemical analyses (CD68 and DSPP) were performed. RESULTS: Bisphenol A-glycidyl methacrylate and polyethylene glycol dimethacrylate release from TheraCal PT was lower than that from TheraCal LC (P < .05). Similar results were obtained for calcium-ion release and calcium weight volume, with ProRoot MTA showing the highest values. In the in vivo evaluation, TheraCal PT showed significantly greater hard tissue formation than TheraCal LC (P < .017). TheraCal PT showed lower CD68 expression and greater DSPP expression than TheraCal LC (P < .017). There were no significant differences in the expression of CD68 or DSPP between the TheraCal PT and ProRoot MTA groups. CONCLUSIONS: Within the limitations of this study, the biocompatibility and bioactivity of TheraCal PT could be comparable to those of ProRoot MTA.

Chemical analysis of mineral trioxide agregate mixed with hyaluronic acids as an accelerant.

MATERIALS AND METHOD: Mineral trioxide aggregate (MTA) has many clinical applications in dentistry; the main drawback is the long setting. The main objective is to investigate and compare the chemical effect of using two commercially available hyaluronic acid hydrogels (HA) instead of distilled water for mixing MTA as an accelerant of setting time. Test materials were divided into three groups; Group 1: (control) mixing MTA with distilled water supplied by the manufacturer; Group 2: mixing MTA with a hybrid cooperative complex of high and low molecular weight HA (Profhilo®); Group 3: mixing MTA with High molecular weight / non-cross-linked HA (Jalupro®). Mixing time, and setting time (initial and final) were determined, Fourier-transform infrared spectroscopy, Energy-dispersive X-ray spectroscopy, Field emission Scanning Electron Microscopy, and X-ray diffraction were performed. RESULTS: mixing time, initial, and final setting time for (MTA + HA) groups were significantly different and lower in comparison to the control group (p < 0.05). This study revealed higher expression of calcium silicate hydrate and calcium hydroxide expression with higher Ca release in the MTA + HA group than the control group. CONCLUSION: commercially available HA demonstrated better chemical properties when used as a mixing medium for MTA. The Mixing and setting time for MTA + HA group were significantly shorter than those of the control group were. Thus, commercially available HA can be used as a mixing medium for MTA.

Comparison of Marginal Adaptation, Surface Hardness and Bond Strength of Resected and Retrofilled Calcium Silicate-based Cements Used in Endodontic Surgery: An In Vitro Study.

AIMS: This study compared the effects of orthograde and retrograde methods on marginal adaptation, surface hardness, and push-out bond strength (POBS) of three calcium silicate-based used in endodontic surgery. MATERIALS AND METHODS: Ninety single-rooted human mandibular premolars were randomly assigned into six groups (n = 15/group): groups I and II, ProRoot mineral trioxide aggregate (MTA) with orthograde and retrograde methods; groups III and IV, Biodentine (BD) with orthograde and retrograde methods; groups V and VI, iRoot BP Plus (BP-RPM) with orthograde and retrograde methods. After obturation, the apical 3 mm of each root was sectioned into two 1-mm-thick root slices and evaluated for marginal adaptation using a scanning electron microscope, surface hardness using Vickers hardness tester and POBS using a universal testing machine. RESULTS: Orthograde placement had a higher maximum gap width than retrograde placement (p < 0.05), but there was no significant difference among the tested materials (p > 0.05). Biodentine exhibited lower surface hardness than ProRoot MTA and iRoot BP Plus (p < 0.05), but there was no significant difference between ProRoot MTA and iRoot BP Plus (p > 0.05). Orthograde placement had higher POBS compared with retrograde placement (p < 0.05). Biodentine had higher POBS than iRoot BP Plus (p < 0.05), but no significant difference from ProRoot MTA (p > 0.05). The failure mode was mainly mixed for all the tested materials regardless of material type or placement technique. CONCLUSION: The retrograde method had better marginal adaptation; however, the orthograde method provided better dislodgement resistance. Biodentine had lower surface hardness than MTA and iRoot BP Plus with both techniques, whereas iRoot BP Plus demonstrated lower dislodging resistance than BD. CLINICAL SIGNIFICANCE: The current findings suggest that orthograde technique, a simpler periapical surgery, with ProRoot MTA provides potentially better surface hardness and POBS than BD and iRoot BP Plus in single-canal teeth.

Designing Calcium Silicate Cements with On-Demand Properties for Precision Endodontics.

Calcium silicate (C3S) cements are available in kits that do not account for patients' specific needs or clinicians' preferences regarding setting time, radiopacity, mechanical, and handling properties. Moreover, slight variations in powder components and liquid content affect cement's properties and bioactivity. Unfortunately, it is virtually impossible to optimize several cement properties simultaneously via the traditional "one variable at a time" strategy, as inputs often induce trade-offs in properties (e.g., a higher water-to-powder ratio [W/P] increases flowability but decreases mechanical properties). Herein, we used Taguchi's methods and genetic algorithms (GAs) to simultaneously analyze the effect of multiple inputs (e.g., powder composition, radiopacifier concentration, and W/P) on setting time, pH, flowability, diametral tensile strength, and radiopacity, as well as prescribe recipes to produce cements with predicted properties. The properties of cements designed with GAs were experimentally tested, and the results matched the predictions. Finally, we show that the cements increased the genetic expression of odonto/osteogenic genes, alkaline phosphatase activity, and mineralization potential of dental pulp stem cells. Hence, GAs can produce cements with tailor-made properties and differentiation potential for personalized endodontic treatment.

Chemomechanical Properties and Biocompatibility of Various Premixed Putty-type Bioactive Ceramic Cements.

INTRODUCTION: This study aimed to evaluate the chemomechanical properties and biocompatibility of recently introduced premixed putty-type bioactive ceramic cements (PPBCs). METHODS: Including ProRoot MTA (PMTA) as a control, BC RRM fast-set putty (BCPT), Well-Root PT (WRPT), One-Fil PT (OFPT), and Endocem MTA premixed (ECPM) were compared to evaluate setting time, radiopacity, pH change, and microhardness. Biocompatibility on human dental pulp cells was compared using CCK-8 assay. Mineralization potential was evaluated using alkaline phosphatase activity, Alizarin Red S (ARS) staining, and quantitative real-time polymerase chain reaction with odontogenic gene marker. For data analysis, 1-way analysis of variance and Tukey's post hoc test were used at the significance level of 95%. RESULTS: Among the PPBCs, BCPT presented the longest (552 ± 27) setting time (minutes) and others showed significantly shorter time than PMTA (334 ± 22) (P < .05). WRPT (6.20 ± 0.54) and OFPT (5.82 ± 0.50) showed significantly higher radiopacity values (mmAl) and others showed similar value compared with PMTA (P > .05). All PPBCs showed high alkaline pH from fresh materials and tended to increase according to time periods from 30 minutes to 12 hours. ECPM showed the highest value of microhardness (81.62 ± 5.90), WRPT showed similar, and others showed lower than PMTA (P < .05). All PPBCs showed biocompatibility in CCK-8 assay. All PPBCs showed similar or better value compared with PMTA in ALP and ARS staining, and ALP and DSPP marker expression (P < .05). CONCLUSIONS: The PPBCs showed clinically acceptable chemomechanical properties and favorable mineralization potential.

The effect of acidity on the physicochemical properties of two hydraulic calcium silicate-based cements and two calcium phosphate silicate-based cements.

BACKGROUND: Bioceramic cements have been widely used in endodontic treatment. This study aimed to compare the microhardness, elastic modulus, internal microstructure and chemical compositions of Biodentine, WMTA, ERRM Putty, iRoot FS and IRM after exposure to PBS, butyric acid, and butyric acid followed by PBS. METHODS: Specimens of each material were prepared and randomly divided into 5 subgroups (n = 5): subgroup A: PBS (pH = 7.4) for 4 days, subgroup B: PBS (pH = 7.4) for 14 days, subgroup C: butyric acid (pH = 5.4) for 4 days, subgroup D: butyric acid (pH = 5.4) for 14 days, subgroup E: butyric acid for 4 days followed by 10 days in contact with PBS. The surface microhardness, elastic modulus, internal morphologic and chemical compositions of specimens were analyzed. RESULTS: The microhardness and elastic modulus values of all materials were significantly higher in the presence of PBS compared to exposure to butyric acid, with the same setting time (P < 0.01). After 4-day exposure to butyric acid followed by 10-day exposure to PBS, the microhardness values returned to the same level as 4-day exposure to PBS (P > 0.05). Biodentine showed significantly higher microhardness and elastic modulus values than other materials, while IRM displayed the lowest (P < 0.01). CONCLUSION: Biodentine seems the most suitable bioceramic cements when applied to an infected area with acidic pH. Further storage at neutral pH, e.g. PBS reverses the adverse effects on bioceramic cements caused by a low pH environment.

Nicotine-magnesium aluminum silicate complexes processed by blending: Characterization for usage as drug carriers in mucoadhesive buccal discs.

Complexation of nicotine (NCT) and magnesium aluminum silicate (MAS) has been formed in the dispersions that required multiple preparation steps. In this study, physical blending was used to produce NCT-MAS complexes. NCT, a free-base liquid state form, was adsorbed onto the MAS granules, where the diffusion and intercalation of NCT molecules into the MAS silicate layers occurred. These processes required a minimum of the 7-d-resting period to reach NCT complete distribution. FTIR, XRD, and 29Si NMR suggest that NCT could interact with MAS via hydrogen bonding, water bridging, and ionic electrostatic force. The 12 % NCT-MAS complexes enabled a sustained release of NCT, after a 2-min burst, in pH 6 phosphate buffer through a particle diffusion-controlled mechanism. Buccal discs formulated with NCT-MAS complexes and sodium alginate (SA) as drug carriers and matrix former could control NCT released through drug diffusion and swelling-controlled mechanisms. NCT release and membrane permeation increased with increasing NCT-MAS complexes or decreasing SA concentration. All NCT-MAS-containing buccal discs exhibited mucoadhesive properties related to the swelling characteristics of SA and MAS. Conclusively, NCT-MAS complexes can be produced through an uncomplicated single-step blending process, and the complexes obtained presented a potential to serve as drug carriers in buccal matrix formulations.

Bismuth release from endodontic materials: in vivo analysis using Wistar rats.

Calcium silicate-based materials are used to block the communication between the root canal and the periodontal ligament space. This brings the materials into contact with tissues and the potential for local and systemic elemental release and movement. The aim of the study was to evaluate the elemental release of bismuth from ProRoot MTA in contact with connective tissues after 30 and 180 days as well as any accumulation in peripheral organs using an animal model. Tricalcium silicate and hydroxyapatite containing 20% bismuth oxide (HAp-Bi) were used as controls. The null hypothesis was that bismuth migrates from tricalcium silicate-based materials when associated with silicon. The materials were examined using scanning electron microscopy, energy dispersive spectroscopy (SEM/EDS) and X-ray diffraction prior to implantation as well as using SEM/EDS, micro X-ray fluorescence and Raman spectroscopy after implantation to assess elemental presence in surrounding tissues. Histological analysis was used to evaluate the changes in tissue architecture and inductively coupled plasma mass spectrometry (ICP-MS) was used to investigate the elemental deposition. For the systemic investigation, routine blood analysis was performed and organs were obtained to evaluate the presence of bismuth and silicon using ICP-MS after acid digestion. In the histological analysis of the implantation sites, macrophages and multinucleated giant cells could be observed after 30 days which after 180 days became a chronic infiltrate; although, no major differences were identified in red and white blood cell analyses and biochemical tests. Implantation altered the materials as observed in the Raman analysis and bismuth was detected both locally and within kidney samples after both periods of analysis, indicating the potential for accumulation of bismuth in this organ. Smaller amounts of bismuth than observed in the kidney were also detected in blood, liver and brain for the ProRoot MTA and HAp-Bi after 180 days. Bismuth was released from the ProRoot MTA locally and was detected systemically and in samples without silicon; thus, the null hypothesis was rejected. The bismuth release demonstrated that this element accumulated both locally and systemically, mainly in the kidneys in comparison with brain and liver regardless of the material base.

Intramedullary bone tissue reaction of ion-releasing resin-modified glass-ionomer restoration versus two calcium silicate-based cements: an animal study.

This comparative study was conducted to assess the intramedullary bone tissue reaction of an ion-releasing resin modified glass-ionomer cement with claimed bioactivity (ACTIVA bioactive resin) restorative material versus Mineral Trioxide Aggregate High Plasticity (MTA HP) and bioceramic putty iRoot BP Plus. Fifty-six adult male Wistar rats were assigned into 4 equal groups (14 rats each). A surgical intramedullary bi-lateral tibial bone defects were performed in rats of the control group I (GI) and left without any treatment to be considered as controls (n = 28). The rats of groups II, III and IV were handled as group I except that the tibial bone defects were filled with ACTIVA, MTA HP and iRoot BP, respectively. In all groups, rats were euthanized after one month and specimens were processed to histological investigation, SEM examination and EDX elemental analysis. In addition, semi-quantitative histomorphometric scoring system was conducted for the following parameters; new bone formation, inflammatory response, angiogenesis, granulation tissue, osteoblasts and osteoclasts. The clinical follow-up outcome of this study revealed the recovery of rats after 4 days post-surgical procedure. It was observed that the animal subjects returned to their routine activities, e.g., walking, grooming and eating. The rats showed normal chewing efficiency without any weight loss or postoperative complications. Histologically, the control group sections showed scanty, very thin, new bone trabeculae of immature woven type located mostly at the peripheral part of the tibial bone defects. These defects exhibited greater amount of thick bands of typically organized granulation tissue with central and peripheral orientation. Meanwhile, bone defects of ACTIVA group showed an empty space surrounded by thick, newly formed, immature woven bone trabeculae. Moreover, bone defects of MTA HP group were partially filled with thick newly formed woven bone trabeculae with wide marrow spaces presented centrally and at the periphery with little amount of mature granulation tissue at the central part. The iRoot BP Plus group section exhibited an observable woven bone formation of normal trabecular structures with narrow marrow spaces presented centrally and at the periphery showed lesser amount of well-organized/mature granulation tissue formation. Kruskal Wallis test revealed total significant differences between the control, ACTIVA, MTAHP and iRoot BP Plus groups (p < 0.05). Meanwhile, Mann-Whitney U test showed significant difference between control and ACTIVA groups, Control and MTA HP groups, control and iRoot BP Plus groups. ACTIVA and MTA HP groups, ACTIVA and iRoot BP Plus (p Ë‚ 0.05) with no significant difference between MTA HP and iRoot BP Plus (p > 0.05). The elemental analysis outcome showed that the lesions of the control group specimens were filled with recently created trabecular bone with limited marrow spaces. EDX tests (Ca and P analysis) indicated a lower degree of mineralization. Lower amounts of Ca and P was expressed in the mapping analysis compared with other test groups. Calcium silicate-based cements induce more bone formation when compared to an ion-releasing resin modified glass-ionomer restoration with claimed bioactivity. Moreover, the bio-inductive properties of the three tested materials are likely the same. Clinical significance: bioactive resin composite can be used as a retrograde filling.

Functional evaluation of mineral trioxide aggregate cement with choline dihydrogen phosphate.

To improve the cytocompatibility of mineral trioxide aggregate (MTA) cement and its ability for reparative dentin formation, the effect of adding choline dihydrogen phosphate (CDHP), which is reported to be biocompatible, to MTA cement was investigated. The L929 cell proliferation showed that the addition of CDHP improved cell viability. The addition of CDHP shortened the setting time of MTA cement, with a significant decrease in consistency above 0.4 g/mL. Diametral tensile strength of the set cement was improved by the addition of 0.4 g/mL CDHP. Solubility was judged to be within the range of clinical application. The spontaneous precipitation of low crystalline hydroxyapatite was examined by immersing the set cement in phosphate buffer saline, and it was found that the ability of the cement with 0.4 g/mL of CDHP was significantly improved compared with that of the cement without CDHP.

Micro-shear bond strength of different calcium silicate materials to bulk-fill composite.

Introduction: This study aimed to compare the micro-shear bond strength (µSBS) performances of two resin-based calcium silicate-based cement (CSC) (TheraCal PT and TheraCal LC), Biodentine, and two modified-MTA CSC materials (NeoMTA 2 and BioMTA+) to bulk-fill restorative material. Materials and Methods: Fifty 3D printed cylindrical resin blocks with a central hole were used (2 mm in depth and 4 mm in diameter). CSCs were placed in the holes (per each group n = 10) and incubated for 24 h. Cylindrical polyethylene molds (2 mm in height and diameter) were used to place the bulk-fill restorative materials on the CSCs and polymerize for 20 s. Then, all specimens were incubated for 24 h at 37 °C at a humidity of 100%. Specimen's µSBSs were determined with a universal testing machine. Data were analyzed with one-way ANOVA (Welch) and Tamhane test. Results: Statistically higher µSBS was found for TheraCal PT (29.91 ± 6.13 MPa) (p < 0.05) respect to all the other materials tested. TheraCal LC (20.23 ± 6.32 MPa) (p > 0.05) reported higher µSBS than NeoMTA 2 (11.49 ± 5.78 MPa) and BioMTA+ (6.45 ± 1.89 MPa) (p < 0.05). There was no statistical difference among TheraCal LC, NeoMTA 2 and Biodentine (15.23 ± 7.37 MPa) and between NeoMTA 2 and BioMTA+ (p > 0.05). Conclusion: Choosing TheraCal PT as the pulp capping material may increase the adhesion and µSBS to the bulk-fill composite superstructure and sealing ability.

Graphene quantum dots incorporated NiAl2O4 nanocomposite based molecularly imprinted electrochemical sensor for 5-hydroxymethyl furfural detection in coffee samples.

5-Hydroxymethyl furfural (HMF) is an intermediate produced by dehydrating sugars, such as fructose, sucrose, and glucose, in an acidic medium or during the Maillard reaction. It also occurs due to the storage of sugary foods at inappropriate temperatures. In addition, HMF is seen as a quality criterion in products. In this study, a novel molecularly imprinted electrochemical sensor based on graphene quantum dots incorporated NiAl2O4 (GQDs-NiAl2O4) nanocomposite was presented for the selective determination of HMF in coffee samples. Various microscopic, spectroscopic, and electrochemical methods were carried out for the structural characterizations of GQDs-NiAl2O4 nanocomposite. The molecularly imprinted sensor was prepared by multi-scanning using cyclic voltammetry (CV) in the presence of 100.0 mM pyrrole monomer and 25.0 mM HMF. After method optimization, the sensor revealed linearity towards HMF in the range of 1.0-10.0 ng L-1 with a detection limit (LOD) of 0.30 ng L-1. The developed MIP sensor's high repeatability, selectivity, stability, and fast response ability can provide reliable HMF detection in beverages, such as coffee, which is heavily consumed.

Biocompatibility, bioactive potential, porosity, and interface analysis calcium silicate repair cements in a dentin tube model.

OBJECTIVES: This study is to evaluate biocompatibility, bioactive potential, porosity, and dentin/material interface of Bio-C Repair (BIOC-R), MTA Repair HP (MTAHP), and Intermediate Restorative Material (IRM). MATERIALS AND METHODS: Dentin tubes were implanted into subcutaneous of rats for 7, 15, 30, and 60 days. Thickness of capsules, number of inflammatory cells (ICs), interleukin-6 (IL-6), osteocalcin (OCN), and von Kossa were evaluated. Porosity and material/dentin interface voids were also analyzed. Data were submitted to ANOVA and Tukey's tests (p < 0.05). RESULTS: IRM capsules were thicker and contained greater ICs and IL-6-immunopositive cells at 7 and 15 days. BIOC-R capsules exhibited higher thickness and ICs at 7 days and greater IL-6 at 7 and 15 days than MTAHP (p < 0.05). At 30 and 60 days, no significant difference was observed among the groups. OCN-immunopositive cells, von Kossa-positive, and birefringent structures were observed in BIOC-R and MTAHP. MTAHP exhibited higher porosity and interface voids (p < 0.05). CONCLUSIONS: BIOC-R, MTAHP, and IRM are biocompatible. Bioceramics materials demonstrate bioactive potential. MTAHP presented the highest porosity and presence of voids. CLINICAL RELEVANCE: BIOC-R and MTAHP have adequate biological properties. BIOC-R demonstrated lower porosity and presence of voids, which may represent better sealing for its clinical applications.

Mechanism of action of Bioactive Endodontic Materials.

A continuous search for bioactive materials capable of supporting the replacement of damaged pulp tissue, with effective sealing potential and biocompatibility, has represented the attention of studies over the last decades. This study involves a narrative review of the literature developed by searching representative research in PUBMED/MEDLINE and searches in textbooks associated with the mechanism of action of bioactive materials (calcium hydroxide, mineral trioxide aggregate (MTA), and calcium silicate cements). The reflective analysis of the particularities of the chemical elements of these materials, considering the tissue and antibacterial mechanism of action, allows a better understanding of the characteristics and similarities in their tissue responses. Calcium hydroxide paste remains the antibacterial substance of choice as intracanal dressing for the treatment of root canal system infections. Calcium silicate cements, including MTA, show a favorable biological response with the stimulation of mineralized tissue deposition in sealed areas when in contact with connective tissue. This is due to the similarity between the chemical elements, especially ionic dissociation, the potential stimulation of enzymes in tissues, and the contribution towards an alkaline environment due to the pH of these materials. The behavior of bioactive materials, especially MTA and the new calcium silicate cements in the biological sealing activity, has been shown to be effective. Contemporary endodontics has access to bioactive materials with similar properties, which can stimulate a biological seal in lateral and furcation root perforations, root-end fillings and root fillings, pulp capping, pulpotomy, apexification, and regenerative endodontic procedures, in addition to other clinical conditions.

Physicochemical properties, cytotoxicity and bioactivity of a ready-to-use bioceramic repair material.

The aim of this study was to evaluate the physicochemical properties, cytotoxicity and bioactivity of a ready-to-use bioceramic material, Bio-C Repair (Angelus), in comparison with White MTA (Angelus) and Biodentine (Septodont). The physicochemical properties of setting time, radiopacity, pH, solubility, dimensional and volumetric changes were evaluated. Biocompatibility and bioactivity were assessed in Saos-2 osteoblast cell cultures by the MTT assay 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide), Neutral Red (NR), Alizarin Red (ARS), and cell migration tests. Statistical analysis was performed by ANOVA, Tukey or Bonferroni tests (α = 0.05). Bio-C Repair had the longest setting time (p < 0.05), but radiopacity and solubility were accordance with the ISO 6876/2012 standards, besides linear expansion. Bio-C Repair and MTA had similar volumetric change (p > 0.05); lower than Biodentine (p < 0.05). All the materials evaluated had an alkaline pH. Bio-C Repair was cytocompatible and promoted mineralized nodule deposition in 21 days and cell migration in 3 days. In conclusion, Bio-C Repair had adequate radiopacity above 3mm Al, solubility less than 3%, dimensional expansion, and low volumetric change. In addition, Bio-C Repair promoted an alkaline pH and presented bioactivity and biocompatibility similar to MTA and Biodentine, showing potential for use as a repair material.

Synergism of Fe and Al salts for the coagulation of dissolved organic matter: Structural developments of Fe/Al-organic matter associations.

Dissolved organic matter (DOM) is distributed ubiquitously in water bodies. Ferric ions can flocculate DOM to form stable coprecipitates; however, Al(III) may alter the structures and stability of Fe-DOM coprecipitates. This study aimed to examine the coprecipitation of Fe, Al, and DOM as well as structural developments of Fe-DOM coprecipitates in relation to changes in Fe/Al ratios and pHs. The results showed that the derived Fe/Al/DOM-coprecipitates could be classified into three categories: (1) at pH 3.0 and 4.5, the corner-sharing FeO6 octahedra associated with Fe-C bonds with Fe/(Fe + Al) ratios ≥0.5; (2) the Fe-C bonds along with single Fe octahedra having Fe/(Fe + Al) ratios of 0.25; (3) at pH 6.0, the ferrihydrite-like Fe domains associated with Fe-C bonds with Fe/(Fe + Al) ratios ≥0.5. At pH 3.0, the Fe and C stability of the coprecipitates increased with increasing Al proportions; nonetheless, pure Al-DOM coprecipitates were unstable even if they exhibited the maximum ability for DOM removal. The associations of Al-DOM complexes and/or DOM-adsorbed Al domains with external surfaces of Fe domain or Fe-DOM coprecipitates may stabilize DOM, leading to lower C solubilization at pH 4.5. Although the preferential formation of Fe/Al hydroxides decreased Fe/Al solubilization at pH 6.0, adsorption instead of coprecipitation of DOM with Fe/Al hydroxides may decrease C stabilization in the coprecipitates. Aluminum cations inhibit DOM releases from Fe/Al/DOM-coprecipitates, promoting the treatment and reuse efficiencies of wastewater and resolving water shortages. This study demonstrates that Al and solution pH greatly affect the structural changes of Fe-DOM coprecipitates and indirectly control the dynamics of Fe, Al, and C concentrations in water.