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1.
Chemosphere ; 286(Pt 2): 131664, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34358891

RESUMO

This work discussed the feasibility and stability of utilizing C-S-H phosphorus recovered products, HAP/C-S-H, to remove Zn(Ⅱ) from aqueous solution and in-situ immobilize Zn(Ⅱ) in contaminated soil. The removal mechanisms of Zn(Ⅱ) by HAP/C-S-H were relatively complex, combining multiple reactions including electrostatic attraction, ion exchange, surface complexation and (co-)precipitation. The removal rate of Zn(Ⅱ) by HAP/C-S-H raised with the increase of pH value, reaching 99.47% at pH of 8 in aqueous solution. The ion strength of background solution negatively affected the adsorption efficiency. The pseudo-second-order model and Langmuir model were more suitable to fit the Zn(Ⅱ) adsorption experimental data for the adsorbent. The adsorption process was endothermic and spontaneous naturally according to thermodynamic parameter. The maximum adsorption capacity of HAP/C-S-H can reach 114.0 mg/g at 308 K. After 28 days of immobilization, the release of Zn(Ⅱ) in soil with HAP/C-S-H remarkably decreased to 0.6 mg/L, compared with control group (2.9 mg/L). BCR sequential extraction results indicated that HAP/C-S-H could convert acid-soluble Zn(Ⅱ) into reducible and residual Zn(Ⅱ), reducing the bioavailability and ecotoxicity of Zn(Ⅱ) in contaminated soil. pH-dependent leaching tests revealed that the soil with HAP/C-S-H had stronger resistance to acid impact.


Assuntos
Solo , Zinco , Adsorção , Compostos de Cálcio , Durapatita , Fósforo , Silicatos
2.
Sci Total Environ ; 804: 150246, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34798753

RESUMO

Deep placement of slow-release nitrogen (N) fertilizers improves the growth and yield of soybean with a high N use efficiency. This study examined the effectiveness of deep placement of lime nitrogen (LN) in reducing N2O emissions in a soybean field and compared it with conventional fertilization. Before sowing soybeans, the starter N fertilizer (16 kg-N ha-1 ammonium sulfate) was mixed in the surface soil and the following four treatments were installed: the control with only the starter N (CT), conventional top-dressing of 60 kg-N ha-1 coated urea (CV), deep placement (20 cm depth) of 100 kg-N ha-1 urea (DU), and deep placement (20 cm depth) of 100 kg-N ha-1 LN (DL). The seasonal patterns of N2O emission rates measured using the closed chamber method differed among the treatments: in CT, N2O emissions were relatively low; in CV, N2O emissions derived from the top-dressed coated urea were observed from 91 days after sowing; in DU and DL, deeply-placed N was converted to N2O in the early growth stages. The cumulative N2O emissions in DL (1.8 kg-N ha-1) during the soybean cultivation period were significantly lower than those in DU (3.1 kg-N ha-1) and CV (2.8 kg-N ha-1), and slightly higher than CT (1.2 kg-N ha-1). The magnitude of N2O emissions was significantly lower in DL than DU, indicating that the choice of N fertilizer is important to reduce N2O emissions. Focusing on N2O emissions per unit coarse grain yield of soybeans, the value in DL was 0.45 g-N kg-1, which was significantly lower than 0.74 g-N kg-1 in CV. In conclusion, the deep placement of LN has the potential to be a sustainable farming method that can promote yields and reduce N2O emissions in soybean cultivation for high yield with N fertilization.


Assuntos
Óxido Nitroso , Soja , Agricultura , Compostos de Cálcio , Fertilizantes/análise , Nitrogênio/análise , Óxido Nitroso/análise , Óxidos , Solo
3.
Sci Total Environ ; 805: 150321, 2022 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-34543790

RESUMO

Limestone is a common amendment used to counteract soil acidity and metal pollution. Understanding the legacy effects of a one-time soil limestone application and subsequent afforestation is needed to evaluate the long-term success of remediation efforts. In this study, soil and tree chemistry were measured across 15 limed sites that were treated and planted 14 to 37 years ago in Sudbury, Ontario, along with two untreated sites. Soil pH and exchangeable base cation (calcium (Ca) and magnesium (Mg)) concentrations were generally elevated especially in surface organic [FH] horizons up to 37-years post limestone treatment. High site-to-site variation however, obscured clear patterns over time and base cation mass budgets were generally unable to account for the mass of added Ca and Mg. Metal partitioning (Kd) in soil was most influenced by soil pH rather than organic matter (OM) showing that metal availability increases as liming effects fade. This study shows that the legacy effects of soil liming can persist for several decades and are most apparent in the forest floor (FH), but legacy effects are quite modest, and it is likely that a considerable amount of limestone has been lost through erosion.


Assuntos
Poluentes do Solo , Solo , Compostos de Cálcio , Metais , Ontário , Óxidos , Poluentes do Solo/análise , Árvores
4.
Chemosphere ; 287(Pt 3): 132095, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34537456

RESUMO

This study investigated the mechanisms involved in CO2 sequestration under the sequence batch and semi-continuous operation using wollastonite in sludge anaerobic digestion. Wollastonite substantially elevated CH4 content in biogas and played a role in CO2 capture. It increased biogas yield of the glucose due to pH buffering effect but did not increase that of the hydrolysate from thermal alkali pretreated sludge. Under the semi-continuous operation, wollastonite improved the CO2 sequestration, but decreased the biogas yield from 166 to 24 mL/g soluble chemical oxygen demand, since seemingly wollastonite residues inhibited microbes in the sludge. However, the use of dialysis bags to wrap wollastonite offset the negative impact of the wollastonite residues in the sludge, thereby increased biogas yield. The present study is conducive to understanding the mechanisms involved in and proving the feasibility of the CO2 sequestration using wollastonite in sludge anaerobic digestion and its impacts on long-term operation. Consequently, the findings of the study provide key parameters and useful guidelines for scaling up and wollastonite application in anaerobic digestion of sewage sludge.


Assuntos
Dióxido de Carbono , Esgotos , Anaerobiose , Reatores Biológicos , Compostos de Cálcio , Diálise Renal , Silicatos
5.
J Colloid Interface Sci ; 605: 33-43, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34311313

RESUMO

HYPOTHESIS: The mechanism of calcium silicate hydrate (CSH) formation, a relevant component of cement, the largest used material by mankind, is well documented. However, the effects of nano-sized materials on the CSH formation have not yet been evaluated. To this aim, a kinetic study on CSH formation via the "pozzolanic reaction" of nanosilica and calcium hydroxide nanoparticles, and in the presence of hydroxypropyl cellulose (HPC) as hydration regulator, is reported in this paper. EXPERIMENTS: The reagents were mixed with water and cured at 10, 20, 30 and 40 °C. The reaction kinetics was studied with differential scanning calorimetry (DSC). A Boundary Nucleation and Growth model (BNGM) combined with a diffusion-limited model was used to analyze the data, yielding induction times, reaction rates, activation energies, nucleation and linear growth rates, and the related diffusion coefficients. FINDINGS: The rate constants kB and kG, which are, respectively, the rate at which the nucleated boundary area transforms, and the rate at which the non-nucleated grains between the boundaries transform, increase with temperature. Their different temperature dependence accounts for the prevailing effect of nucleation over nuclei growth at progressively lower temperatures. The nucleation rate, IB, is strongly enhanced when using nanomaterials, while the linear growth rate, G, is limited by the tightly packed structure of the transforming matrix. HPC influences the kinetics between 10 and 30 °C; at 40 °C the temperature effect becomes predominant. HPC delays induction and acceleration periods, increases Ea(kB), and enhances the reaction efficiency during the diffusion regime, by retaining and delivering water over the matrix, thus allowing a higher water consumption in the hydration reaction of CSH.


Assuntos
Hidróxido de Cálcio , Nanopartículas , Compostos de Cálcio , Cinética , Teste de Materiais , Microscopia Eletrônica de Varredura , Silicatos , Dióxido de Silício , Difração de Raios X
6.
J Hazard Mater ; 421: 126745, 2022 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-34364206

RESUMO

Sulfide precipitation is an efficient method to remove Cu(II) and As(III) from strongly acidic wastewater, but the instantaneous release of H2S from traditional sulfuration reagents causes serious H2S pollution. Moreover, the obtained precipitates are mixtures of CuS and As2S3, leading to difficulties in resource recovery. In this study, a calcium sulfide-organosilicon complex (CaS-OSCS), in which CaS was coated into a matrix of {[O1.5Si(CH2)3NH]CS}n (OSCS) via the coordination bonding, was developed. OSCS, as a matrix of CaS-OSCS, can ensure the sustained and stable release of H2S under strongly acidic conditions owing to its low swelling (1.75% swelling ratio) and excellent acid resistance. The release longevity of H2S from CaS-OSCS extended from 5 min up to 50 min compared with that from CaS because the hydrophobic OSCS prevented solution diffusing to the pores of CaS-OSCS and thus slowed down the hydrolysis of CaS in pores. 99% of Cu(II)/As(III) was precipitated without H2S escape, and the dosage of sulfuration reagents was reduced by 30%. In addition, CaS-OSCS improved the selective separation of copper from wastewater, and a separation factor between Cu(II) and As(III) reached 2376. This study provides a potential approach for the elimination of H2S pollution and selective recovery of copper.


Assuntos
Sulfeto de Hidrogênio , Águas Residuárias , Compostos de Cálcio , Preparações de Ação Retardada , Sulfetos
7.
J Environ Manage ; 301: 113855, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34597947

RESUMO

CaSO4 reduction decomposition for CaO preparation provides a theoretical basis for the utilization of the industrial byproduct, gypsum. In this study, the effects of temperature (950 °C-1150 °C), CO2/CO partial-pressure ratio (1-15), CO concentration (1%-5%), and O2 concentration (1%-7%) on the preparation of CaO from CaSO4 by CO reduction decomposition under different reaction atmospheres were investigated. The physical properties of CaO prepared by the decomposition of CaSO4 and CaCO3 were analyzed and compared. Finally, the reaction mechanism of the reduction decomposition of CaSO4 to CaO by CO was studied. The findings reveal that CaSO4 can be completely decomposed into CaO when the reaction temperature exceeds 1000 °C, CO% ≥ 2%, and P(CO2)/P(CO) ≥ 8. Furthermore, the addition of an appropriate amount of O2 can improve the yield of CaO in the products. In an O2-CO-N2 atmosphere, where O2% = 7% and CO% = 16%, CaSO4 can be completely decomposed into CaO without the addition of CO2. The physical properties of CaO prepared by the reduction and decomposition of CaSO4 are better than those prepared by the calcination of CaCO3. An analysis of the reaction mechanism of the reduction decomposition of CaSO4 by CO reveals that CaSO4 generates CaO and CaS simultaneously. In addition, CaS can react with unreacted CaSO4 to form CaO. Furthermore, it can react with CO2 to produce CaO if an appropriate amount of CO2 is added to the reaction atmosphere. The secondary interactions of CaS with CaSO4 and CO2 can significantly improve the yield of CaO in the product.


Assuntos
Compostos de Cálcio , Sulfato de Cálcio , Temperatura
8.
J Environ Manage ; 301: 113923, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34634722

RESUMO

Phosphate is a major pollutant that deteriorates water quality and causes eutrophication, a novel calcium silicate hydrate composite cryogel (Cry-CSH) was thus successfully prepared for phosphate removal and recovery in this work. Calcium silicate hydrate (C-S-H) was mixed with the gel precursor (7.5% w/w) prepared from native starch and limewater (saturated calcium hydroxide solution as the cross-linker). The mixture was frozen and thawed for 3 cycles giving an interconnected macroporous composite. This had C-S-H nanoparticles (75 mg) immobilized on a monolithic floatable cryogel network (2.5 cm diameter × 1.0 cm height) enabling an easier recovery and without the losses that occur when using C-S-H nanoparticles. The phosphate adsorption reaches equilibrium at 120 min with adsorption capacity of 2.50 mgPO43-/gCry-CSH (65.42 mgPO43-/gC-S-H) under optimum conditions. Adsorption equilibrium data were well fit by the Freundlich isotherm model, while kinetic results were well fit by the pseudo second-order model. The calculated activation energy (Ea) of 43.9 kJ/mol indicates chemical adsorption, while a positive change in enthalpy (ΔH0, 19.3 kJ/mol) indicates the endothermic nature of phosphate adsorption. Cry-CSH can remove phosphate from wastewater and effluent samples with excellent removal efficiency (>98%). It can float on water surface for at least 105 days without damage, while its phosphate adsorbed form can be biodegraded within 10 days under soil buried conditions. Thus, this work demonstrated the significant potential of Cry-CSH for practical and environmentally friendly phosphate removal and recovery.


Assuntos
Fosfatos , Poluentes Químicos da Água , Adsorção , Compostos de Cálcio , Criogéis , Cinética , Silicatos , Amido
9.
Food Chem ; 370: 131353, 2022 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-34788964

RESUMO

A highly effective molecularly imprinted electrochemiluminescence sensor was constructed for prometryn determination in environmental and biological samples by using perovskite quantum dots coated with a molecularly imprinted silica layer (MIP/CsPbBr3-QDs) as the recognition and response element. MIP/CsPbBr3-QDs were immobilized on a glassy carbon electrode (GCE) through electropolymerization, and the electrochemiluminescence (ECL) response of MIP/CsPbBr3-QDs could be motivated under the condition of H2O2 as co-reactant. ECL signal was selectively quenched with prometryn by hindering electron transfer and directly proportional to the logarithm of prometryn concentration (0.10-500.0 µg/L) with a correlation coefficient of 0.9960. Limits of detection in fish and seawater samples were 0.010 µg/kg and 0.050 µg/L, respectively. Excellent recoveries of 88.0%-106.0% were acquired for fish and seawater samples with a relative standard deviation below 4.2%. The constructed MIECL sensor based on MIP/CsPbBr3-QDs showed good stability, accuracy, and precision for sensitive detection of prometryn in aquaculture products and environmental samples.


Assuntos
Impressão Molecular , Pontos Quânticos , Animais , Compostos de Cálcio , Peróxido de Hidrogênio , Limite de Detecção , Polímeros Molecularmente Impressos , Óxidos , Prometrina , Titânio
10.
Braz. j. oral sci ; 20: e214073, jan.-dez. 2021. ilus
Artigo em Inglês | LILACS, BBO - Odontologia | ID: biblio-1282556

RESUMO

Aim: this study aimed to compare the sealing ability of two types of commercially available calcium silicate bioceramic based root canal sealers and a resin based root canal sealer. Methods: Twenty one single-rooted teeth were used, samples (n= 21) were randomly divided into three groups according to the sealer used (group A; ADSEAL, group B; Wellroot, group C; Ceraseal). Roots were then cleaved longitudinally in the labiolingual direction; all samples were then sectioned at three, six, and nine mm from the root tip. The penetration of sealers into the dentinal tubules was examined at 1000x with a scanning electron microscope. Data were tested for normality using Shapiro Wilk test. ANOVA test was used for analyzing normally distributed data followed by Bonferroni post hoc test for pair-wise comparison. Significance level p≤0.001. Results: groups B and C showed better sealing ability than group A in all the three sections. The coronal section showed higher sealing ability than the middle section followed by the apical section in the three tested groups. Conclusion: it can be concluded that both calcium silicate-based sealers had better sealing ability and higher bond strength than the resin epoxy- based sealer


Assuntos
Materiais Restauradores do Canal Radicular , Silicatos , Compostos de Cálcio , Resinas Epóxi , Tomografia com Microscopia Eletrônica
11.
Biosensors (Basel) ; 11(11)2021 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-34821630

RESUMO

CH3NH3PbBr3 perovskite thin film is used as a guided-wave layer and coated on the surface of an Au film to form the Au-perovskite hybrid structure. Using the hybrid structure, a perovskite-based guided-wave surface plasmon resonance (GWSPR) biosensor is proposed with high angular sensitivity. First, it is found that the electric field at the sensing interface is improved by the CH3NH3PbBr3 perovskite thin film, thereby enhancing the sensitivity. The result demonstrates that the angular sensitivity of the Au-perovskite-based GWSPR biosensor is as high as 278.5°/RIU, which is 110.2% higher than that of a conventional Au-based surface plasmon resonance (SPR) biosensor. Second, the selection of the coupling prism in the configuration of the GWSPR biosensor is also analyzed, and it indicates that a low refractive index (RI) prism can generate greater sensitivity. Therefore, the low-RI BK7 prism is served as the coupling prism for the proposed GWSPR biosensor. Finally, the proposed GWSPR sensing structure can not only be used for liquid sensing, but also for gas sensing, and it has also been demonstrated that the GWSPR gas sensor is 2.8 times more sensitive than the Au-based SPR gas sensor.


Assuntos
Técnicas Biossensoriais , Compostos de Cálcio , Óxidos , Refratometria , Ressonância de Plasmônio de Superfície , Titânio
12.
J Indian Soc Pedod Prev Dent ; 39(3): 303-309, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34810349

RESUMO

Background: Pulpotomy is a vital pulp therapy performed in carious pulp exposures in teeth in which the inflamed coronal pulp is removed and medicament is placed to conserve the vital root pulps. Recently, simvastatin which is a cholesterol-lowering drug has been found to be associated with the pulp regenerative potential. Aim: The aim of this parallel two-arm randomized control trial was to evaluate and compare the clinical and radiographic efficacy of diode laser (DL) and simvastatin gel (SG) in pulpotomy of carious primary molars. Methods: Hundred primary molars (in 98 children, 65 males, 33 females with age 4-8 years) requiring pulpotomy were randomized into the DL or SG group. Pulpotomy was performed as per the standardized protocol; thereafter, all teeth were restored with resin modified glass ionomer cement followed by stainless steel crowns. Follow-up evaluations were done at 3 and 12 months using clinical and radiographic criteria. Statistical analysis was done using Chi-square test at a significance level of 0.05. Results: At 12 months, out of 92 teeth available for clinical and radiographic evaluation by blinded evaluators, DL group showed clinical and radiographic success rates of 76.1% and 52.1%, while SG group showed 80.4% and 65.2% success rates, respectively. There was no statistically significant difference between the efficacy of two techniques clinically (P = 0.49) or radiographically (P = 0.30). Conclusions: Both SG and DL had similar efficacy for primary tooth pulpotomy, clinically and radiographically after 12 months. Considering its ease of application and low-cost, SG can be recommended as a potential pulpotomy medicament in primary molars.


Assuntos
Cárie Dentária , Pulpotomia , Compostos de Alumínio , Compostos de Cálcio , Criança , Pré-Escolar , Cárie Dentária/tratamento farmacológico , Combinação de Medicamentos , Feminino , Humanos , Lasers Semicondutores/uso terapêutico , Masculino , Dente Molar/diagnóstico por imagem , Dente Molar/cirurgia , Óxidos , Silicatos , Sinvastatina , Dente Decíduo , Resultado do Tratamento
13.
Braz Dent J ; 32(3): 65-74, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34755791

RESUMO

This study investigated the effect of three commercial calcium silicate-based materials (CSBM) on cytotoxicity and pro-and anti-inflammatory cytokines production in cultured human periodontal ligament stem cells (hPDLSCs). Culture of hPDLSCs was established and characterized. Extracts of Bio-C Sealer (Angelus, Londrina, PR, Brazil), MTA Fillapex (Angelus, Londrina, PR, Brazil) and PBS Cimmo HP (Cimmo Soluções em Saúde, Pouso Alegre, MG, Brazil) were prepared by placing cement specimens (5 x 3 mm) in culture medium. Then, the extracts were serially two-fold diluted (1, 1:2, 1:4, 1:8, 1:16) and inserted into the cell-seeded wells for 24, 48 and 72 h for MTT assays. TNF-α and IL-10 cytokines were quantified by ELISA at 24h-cell supernatants. Data were analyzed by ANOVA and Tukey's test (α = 0.05). All CSBM exhibited some cytotoxicity that varied according to extract concentration and time of evaluation. MTA Fillapex presented the highest cytotoxic effects with significant reduction of metabolic activity/cell viability when compared to Bio-C Sealer and Cimmo HP®. TNF-α was significantly upregulated by the three tested cements (p < 0.05) while only MTA Fillapex significantly upregulated IL-10 in comparison to control. Taken collectively, the results showed that PBS Cimmo HP®, Bio-C Sealer and MTA Fillapex present mild and transient cytotoxicity and slightly induced TNF-α production. MTA Fillapex upregulated IL-10 release by hPDLSCs.


Assuntos
Compostos de Cálcio/efeitos adversos , Ligamento Periodontal , Materiais Restauradores do Canal Radicular/efeitos adversos , Silicatos/efeitos adversos , Células-Tronco/efeitos dos fármacos , Compostos de Alumínio , Citocinas/metabolismo , Humanos , Teste de Materiais , Óxidos , Ligamento Periodontal/citologia
14.
Braz Dent J ; 32(3): 21-31, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34755787

RESUMO

This study assessed the fracture resistance of simulated immature teeth reinforced with calcium aluminate cement (CAC) or mineral trioxide aggregate (MTA) containing calcium carbonate nanoparticles (nano-CaCO3). The microstructural arrangement of the cements and their chemical constitution were also evaluated. Forty-eight canines simulating immature teeth were distributed into 6 groups (n=8): Negative control - no apical plug or root canal filling; CAC - apical plug with CAC; CAC/nano-CaCO3 - apical plug with CAC+5% nano-CaCO3; MTA - apical plug with MTA; MTA/nano-CaCO3 - apical plug with MTA+5% nano-CaCO3; and Positive control - root canal filling with MTA. The fracture resistance was evaluated in a universal testing machine. Samples of the cements were analyzed under Scanning Electron Microscope (SEM) to determine their microstructural arrangement. Chemical analysis of the cements was performed by Energy Dispersive X-ray Spectroscopy (EDS). The fracture resistance of CAC/nano-CaCO3 was significantly higher than the negative control (p<0.05). There was no significant difference among the other groups (p>0.05). Both cements had a more regular microstructure with the addition of nano-CaCO3. MTA samples had more calcium available in soluble forms than CAC. The addition of nano-CaCO3 to CAC increased the fracture resistance of teeth in comparison with the non-reinforced teeth. The microstructure of both cements containing nano-CaCO3 was similar, with a more homogeneous distribution of lamellar- and prismatic-shaped crystals. MTA had more calcium available in soluble forms than CAC.


Assuntos
Materiais Restauradores do Canal Radicular , Fraturas dos Dentes , Compostos de Alumínio , Compostos de Cálcio , Cimentos Dentários , Combinação de Medicamentos , Humanos , Óxidos , Obturação do Canal Radicular , Silicatos , Ápice Dentário
15.
Science ; 374(6569): 820-821, 2021 11 12.
Artigo em Inglês | MEDLINE | ID: mdl-34762481

RESUMO

[Figure: see text].


Assuntos
Compostos de Cálcio , Óxidos , Titânio
16.
J Clin Pediatr Dent ; 45(5): 306-311, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34740264

RESUMO

INTRODUCTION: Bioceramic materials, gray and white mineral trioxide aggregate (GMTA, WMTA), have been shown to have high rates of success in various endodontic applications. A major drawback is their tendency to discolor teeth compared to Biodentine (BD), that has been claimed not to discolor teeth. The aim of this study was to compare tooth discoloration after applying different pulpotomy base materials (BD, GMTA and WMTA). STUDY DESIGN: Forty human incisors teeth were used in this study. Coronal access was achieved by a Tungsten Carbide drill, and the pulp chambers were accessed and chemo-mechanically debrided. Each material was placed in the pulp chamber, up to the cervical sectioning level. All specimens were incubated at 37°C and 100% humidity for three months and have been evaluated before the study and weekly. Color was assessed according to the CIE L*a*b* color space system. RESULTS: ΔE of all experimental groups (GMTA, WMTA and BD) were significantly different from the control group at all time points (P<0.05). Color changes in the GMTA and WMTA groups, had no statistically significant differences, but showed higher discoloration compared to BD group in the cervical part of the crown, since week 1 (P<0.05). WMTA group showed significant discoloration in the cervical part as of week 1 (P<0.05), and gradually increased over time (Figure 2). BD group showed no significantly discoloration over time. GMTA group showed the significant discoloration at week 1 and week 14 (P<0.05). CONCLUSIONS: both GMTA and WMTA pulpotomy materials may discolor tooth structure over time in an extracted permanent anterior tooth model. When choosing bioceramic pulpotomy material, BD may be preferable in esthetic area.


Assuntos
Materiais Restauradores do Canal Radicular , Descoloração de Dente , Compostos de Alumínio/efeitos adversos , Compostos de Cálcio/efeitos adversos , Coroas , Combinação de Medicamentos , Humanos , Incisivo , Óxidos/efeitos adversos , Pulpotomia , Silicatos/efeitos adversos , Coroa do Dente , Descoloração de Dente/induzido quimicamente
17.
Braz Dent J ; 32(4): 1-7, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34787245

RESUMO

This study evaluated the 3D quality of root-end filling, assessing the presence (volume and percentage) of marginal gaps and internal voids formed after retro-filling with three calcium silicate-based materials: MTA Angelus (Angelus Soluçoes Odontologicas, Londrina, PR, Brazil), Biodentine (Septodont Ltd., Saint Maur-des-Faussés, France) and Neo MTA Plus (Avalon Biomed Inc., Bradenton, Florida, US). Thirty human, extracted, single rooted teeth were used. Orthograde root canal treatment, root resection (3mm shorter than the apex) and retrograde cavity preparation with ultrasonic tips were performed. Teeth were divided into 3 groups (n =10 each) following a stratified randomization according to the initial volume of the root-end cavity. After retrofilling, samples were stored for 7 days. Then, two rounds of micro-CT scans were performed: soon after root-end preparation (with the cavity still empty) and 7 days after root-end filling. Marginal gaps, internal voids volume (mm3 and %), as well as, the overall defects (sum of gaps and voids) were evaluated. Statistics compared the three groups in relation to those defects. There was not statistical difference between groups regarding the marginal gaps (P≥ 0.05), the internal voids (P≥ 0.05), and the overall defects (P≥ 0.05). Median (mm3) and % of overall air-entrapment defects (gaps and/or voids) was: 0.004mm3 and 1.749% for MTA Angelus, 0.018mm3 and 6.660% for Biodentine, and 0.012mm3 and 4.079% for Neo MTA Plus. All materials had gaps and/or voids. No differences were found between MTA Angelus, Biodentine and Neo MTA Plus.


Assuntos
Materiais Restauradores do Canal Radicular , Compostos de Cálcio , Humanos , Obturação do Canal Radicular , Tratamento do Canal Radicular , Silicatos , Microtomografia por Raio-X
18.
Braz Dent J ; 32(4): 8-18, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34787254

RESUMO

The aim of this study was to evaluate the physicochemical properties, cytocompatibility and antibiofilm activity of a new calcium silicate-based endodontic sealer, Sealer Plus BC (MK Life, Brazil), in comparison with TotalFill BC Sealer (FKG Dentaire SA, Switzerland) and AH Plus (Dentsply, Germany). Setting time and flow were evaluated based on ISO 6876 standard. The pH was evaluated after different periods, and radiopacity by radiographic analysis (mmAl). Solubility (% mass loss) and volumetric change (by micro-CT) were assessed after 30 days of immersion in distilled water. Cytocompatibility was assessed by methyltetrazolium (MTT) and neutral red (NR) assays, after exposure of Saos-2 cells to the sealer extract for 24 h. An additional analysis was performed by using MTT assay after 1, 3 and 7 days of exposure of Saos-2 to the sealers 1:8 dilution extracts. Antibiofilm activity against Enterococcus faecalis and/or Candida albicans was evaluated by crystal violet assay and modified direct contact test. The physicochemical properties were analyzed using ANOVA/Tukey tests; MTT and NR data were analyzed by ANOVA and Bonferroni tests; the antimicrobial tests were analyzed by Kruskal-Wallis and Dunn tests (α=0.05). Sealer Plus BC had proper setting time, radiopacity, flow and alkalization capacity. Sealer Plus BC was significantly more soluble than AH Plus (p<0.05) and presented volumetric change similar to AH Plus and TotalFill BC (p>0.05). Sealer Plus BC presented antibiofilm activity and no cytotoxic effect. In conclusion, although Sealer Plus BC had higher solubility, this sealer showed proper physicochemical properties, cytocompatibility, and antibiofilm activity.


Assuntos
Materiais Restauradores do Canal Radicular , Biofilmes , Compostos de Cálcio/farmacologia , Resinas Epóxi , Teste de Materiais , Materiais Restauradores do Canal Radicular/farmacologia , Silicatos/farmacologia
19.
Nanoscale Horiz ; 6(12): 939-970, 2021 11 22.
Artigo em Inglês | MEDLINE | ID: mdl-34652346

RESUMO

The unique electron spin, transfer, polarization and magnetoelectric coupling characteristics of ABO3 multiferroic perovskite materials make them promising candidates for application in multifunctional nanoelectronic devices. Reversible ferroelectric polarization, controllable defect concentration and domain wall movement originated from the ABO3 multiferroic perovskite materials promotes its memristive effect, which further highlights data storage, information processing and neuromorphic computing in diverse artificial intelligence applications. In particular, ion doping, electrode selection, and interface modulation have been demonstrated in ABO3-based memristive devices for ultrahigh data storage, ultrafast information processing, and efficient neuromorphic computing. These approaches presented today including controlling the dopant in the active layer, altering the oxygen vacancy distribution, modulating the diffusion depth of ions, and constructing the interface-dependent band structure were believed to be efficient methods for obtaining unique resistive switching (RS) behavior for various applications. In this review, internal physical dynamics, preparation technologies, and modulation methods are systemically examined as well as the progress, challenges, and possible solutions are proposed for next generation emerging ABO3-based memristive application in artificial intelligence.


Assuntos
Inteligência Artificial , Redes Neurais de Computação , Compostos de Cálcio , Armazenamento e Recuperação da Informação , Óxidos , Titânio
20.
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