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1.
J Clin Pediatr Dent ; 45(2): 112-116, 2021 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-33951168

RESUMEN

OBJECTIVE: Calcium silicate-based cements (CSCs) may lead to coronal staining in young permanent teeth over the time. The purpose of this study was to evaluate and compare the long-term tooth discoloration induced by different CSCs. STUDY DESIGN: Ninety freshly-extracted human molars were assigned randomly into 6 groups (n=15/group) according to the CSC used as a pulpotomy material: ProRoot MTA, MTA Angelus, NeoMTA, EndoSequence Putty, Biodentine and Negative control (No cement). The color was assessed at baseline, and thereafter at 3, 6, 12 and 24 months by using both a spectrophotometer and digital images taken with and without a cross-polarizing filter. The time-dependent changes in color (ΔE) were compared within and among groups using Analysis of Variance. RESULTS: Angelus MTA and ProRooT MTA showed severe coronal discoloration (p>0.05) starting at 3 months. ΔE values of NeoMTA, EndoSequence Bioceramic Putty and Biodentine were below the perceptibility threshold, with Biodentine showing greater ΔE values than NeoMTA and EndoSequence Putty in the absence of statistical significance (p>0.05). CONCLUSIONS: Discoloration elicited by CSCs may develop soon after placement, and continue to increase for up to two years. Angelus MTA and ProRooT MTA cannot be recommended for vital pulp therapies in the esthetic zone of young individuals.


Asunto(s)
Decoloración de Dientes , Diente , Compuestos de Aluminio/efectos adversos , Compuestos de Calcio/efectos adversos , Cementos Dentales/efectos adversos , Combinación de Medicamentos , Humanos , Óxidos/efectos adversos , Pulpotomía , Silicatos/efectos adversos , Decoloración de Dientes/inducido químicamente
2.
Water Sci Technol ; 83(8): 1973-1986, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33905366

RESUMEN

Long-term accumulation of cobalt-containing wastewater may also pollute groundwater and cause a large amount of loss of valuable metals. Therefore, the comprehensive utilization of cobalt-containing wastewater must be realized, especially as cobalt itself is a very important strategic resource. This paper proposes a membrane electroconversion method to separate cobalt ions from cobalt-containing wastewater and prepare cobalt hydroxide. In addition, the electrolysis process was optimized, and single-factor experiments such as the initial concentration, cobalt ions, current density, temperature etc., and economic calculations such as current efficiency were explored. The electrolysis product was calcined as the precursor to obtain the oxide Co3O4, and the calcination experiment was also optimized. In this concentration range, more than 90% of cobalt can be recovered within 2 h.


Asunto(s)
Cobalto , Aguas Residuales , Electrólisis , Óxidos
3.
Sensors (Basel) ; 21(5)2021 Mar 09.
Artículo en Inglés | MEDLINE | ID: mdl-33803466

RESUMEN

The breath gas analysis through gas phase chemical analysis draws attention in terms of non-invasive and real time monitoring. The array-type sensors are one of the diagnostic methods with high sensitivity and selectivity towards the target gases. Herein, we presented a 2 × 4 sensor array with a micro-heater and ceramic chip. The device is designed in a small size for portability, including the internal eight-channel sensor array. In2O3 NRs and WO3 NRs manufactured through the E-beam evaporator's glancing angle method were used as sensing materials. Pt, Pd, and Au metal catalysts were decorated for each channel to enhance functionality. The sensor array was measured for the exhaled gas biomarkers CH3COCH3, NO2, and H2S to confirm the respiratory diagnostic performance. Through this operation, the theoretical detection limit was calculated as 1.48 ppb for CH3COCH3, 1.9 ppt for NO2, and 2.47 ppb for H2S. This excellent detection performance indicates that our sensor array detected the CH3COCH3, NO2, and H2S as biomarkers, applying to the breath gas analysis. Our results showed the high potential of the gas sensor array as a non-invasive diagnostic tool that enables real-time monitoring.


Asunto(s)
Gases , Nanotubos , Biomarcadores , Pruebas Respiratorias , Óxidos
4.
Artículo en Inglés | MEDLINE | ID: mdl-33809051

RESUMEN

Selenium (Se) is an essential and crucial micronutrient for humans and animals, but excessive Se brings negativity and toxicity. The adsorption and oxidation of Se(IV) on Mn-oxide surfaces are important processes for understanding the geochemical fate of Se and developing engineered remediation strategies. In this study, the characterization of simultaneous adsorption, oxidation, and desorption of Se(IV) on δ-MnO2 mineral was carried out using stirred-flow reactors. About 9.5% to 25.3% of Se(IV) was oxidized to Se(VI) in the stirred-flow system in a continuous and slow process, with the kinetic rate constant k of 0.032 h-1, which was significantly higher than the apparent rate constant of 0.0014 h-1 obtained by the quasi-level kinetic fit of the batch method. The oxidation reaction was driven by proton concentration, and its rate also depended on the Se(IV) influent concentration, flow rate, and δ-MnO2 dosage. During the reaction of Se(IV) and δ-MnO2, Mn(II) was produced and adsorbed strongly on Mn oxide surfaces, which was evidenced by the total reflectance Fourier transform infrared (ATR-FTIR) results. The X-ray photoelectron spectroscopy (XPS) data indicated that the reaction of Se(VI) on δ-MnO2 produced Mn(III) as the main product. These results contribute to a deeper understanding of the interface chemical process of Se(IV) with δ-MnO2 in the environment.


Asunto(s)
Compuestos de Manganeso , Óxidos , Adsorción , Humanos , Cinética , Oxidación-Reducción , Ácido Selenioso
5.
Artículo en Inglés | MEDLINE | ID: mdl-33809592

RESUMEN

The ubiquitous occurrence of heavy metals in the aquatic environment remains a serious environmental and health issue. The recovery of metals from wastes and their use for the abatement of toxic heavy metals from contaminated waters appear to be practical approaches. In this study, manganese was recovered from groundwater treatment sludge via reductive acid leaching and converted into spherical aggregates of high-purity MnO2. The as-synthesized MnO2 was used to adsorb Cu(II) and Pb(II) from single-component metal solutions. High metal uptake of 119.90 mg g-1 for Cu(II) and 177.89 mg g-1 for Pb(II) was attained at initial metal ion concentration, solution pH, and temperature of 200 mg L-1, 5.0, and 25 °C, respectively. The Langmuir isotherm model best described the equilibrium metal adsorption, indicating that a single layer of Cu(II) or Pb(II) was formed on the surface of the MnO2 adsorbent. The pseudo-second-order model adequately fit the Cu(II) and Pb(II) kinetic data confirming that chemisorption was the rate-limiting step. Thermodynamic studies revealed that Cu(II) or Pb(II) adsorption onto MnO2 was spontaneous, endothermic, and had increased randomness. Overall, the use of MnO2 prepared from groundwater treatment sludge is an effective, economical, and environmentally sustainable substitute to expensive reagents for toxic metal ion removal from water matrices.


Asunto(s)
Agua Subterránea , Contaminantes Químicos del Agua , Purificación del Agua , Adsorción , Concentración de Iones de Hidrógeno , Cinética , Plomo , Compuestos de Manganeso , Óxidos , Aguas del Alcantarillado , Termodinámica , Contaminantes Químicos del Agua/análisis
6.
J Environ Manage ; 288: 112443, 2021 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-33827019

RESUMEN

Electrokinetic remediation (EK) is a promising in-situ technique for removing mercury (Hg) from contaminated sites; yet it demands long operational periods when conventional electrodes are used. Herein, we investigate the effectiveness of lab-prepared cathodes (Cu foam coated with reduced graphene oxide (rGO) or manganese oxide (MnO2)) to enhance Hg removal rates from sediment by EK. Although short term (2 h) Hg removal rates were insignificantly different (p-value > 0.05) when using the uncoated and coated Cu foam cathodes, long term (60 h) operations saw greater Hg removal by coated Cu foam cathodes over pure Cu foam, probably owing to the time required for Hg to migrate towards the electrodes from sediment. The highest Hg removal at the cathode was achieved when an αMnO2-coated Cu foam cathode was used with a strong-base anion exchange membrane (AEM) in the system. Using H3PO4, as a cathodic electrolyte resulted in a higher Hg removal efficiency than using NaCl and HCl electrolytes. Electromigration was found to be the dominant Hg-ions (e.g. HHgO2-, Hg2+) transport mechanism in the marine sediment during remediation. Overall, this research demonstrates that employing enhanced electrodes and AEMs can enhance Hg removal by EK processes in relatively shorter operating times than conventional EK processes.


Asunto(s)
Restauración y Remediación Ambiental , Mercurio , Contaminantes del Suelo , Electrodos , Sedimentos Geológicos , Compuestos de Manganeso , Óxidos , Contaminantes del Suelo/análisis
7.
BMC Oral Health ; 21(1): 192, 2021 04 13.
Artículo en Inglés | MEDLINE | ID: mdl-33849516

RESUMEN

BACKGROUND: The biocompatibility of NeoMTA Plus® (Avlon BioMed Inc., Bradenton, Fl) as a furcal perforation repair material is not fully understood. This study compares the biocompatibility of Mineral Trioxide Aggregate (MTA Angelus) and NeoMTA Plus® as delayed furcation perforation repair materials. METHODS: Pulpotomy and root canal obturation were performed in 72 premolars in six mongrel dogs and then a standardized furcal perforation was performed. The coronal access was left open for three weeks. After curetting, cleaning and drying of the perforations, these teeth were divided into three equal groups (N = 24 teeth/ 2 dogs each) according to the material used for perforation repair; group I: NeoMTA Plus®, group II: MTA Angelus and group III: no material (positive control). The coronal access cavities were sealed with a filling material. The inflammatory cell count and qualitative pathology (presence of calcific bridge, configuration of fibrous tissue formed, examination of tissue surrounding the furcation area, histology of intraradicular bone and the inflammatory nature of tissues) were carried out after one week (subgroup A, N = 8 teeth), one month (subgroup B, N = 8 teeth) and three months (subgroup C, N = 8 teeth). The inflammatory cell count was expressed as mean ± SD and statistically analyzed. P-value < 0.05 was considered significant. RESULTS: In all subgroups, the control group exhibited the highest number of inflammatory cell count, followed by MTA Angelus group and the least inflammatory cell count was shown by NeoMTA Plus® group. There was a significant difference in the inflammatory cell count between the NeoMTA Plus® and MTA Angelus after one week (P < 0.05) while no significant differences were recorded between them after one month and three months (P > 0.05). In contrast to group II, there was no significant differences in inflammatory cell count between the subgroups in groups I and III (P > 0.05). NeoMTA Plus® exhibited better qualitative pathological features than MTA Angelus after one week and nearly similar features after one month and three months of repair. CONCLUSION: NeoMTA Plus® has a better early biocompatibility than MTA Angelus after one week of delayed furcation perforation repair and a similar late biocompatibility after one month and three months.


Asunto(s)
Materiales de Obturación del Conducto Radicular , Silicatos , Resinas Acrílicas , Compuestos de Aluminio , Animales , Bismuto , Compuestos de Calcio/uso terapéutico , Perros , Combinación de Medicamentos , Óxidos/uso terapéutico , Pulpotomía , Silicatos/uso terapéutico
8.
Water Sci Technol ; 83(7): 1591-1604, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33843745

RESUMEN

Dairy plants produce 1 to 4 L of wastewater per 1 L of processed milk. The wastewater contains high values of chemical oxygen demand (COD) and biochemical oxygen demand (BOD) concentrations, in addition to high levels of dissolved solids. In this study, synthesized copper oxide nanoparticles (CuONPs) coupled with Sophora Japonica fruit, were used as an adsorbent, for the first time, to treat the effluent of dairy plants in a batch adsorption process. The analysis techniques, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) were utilized to characterize the adsorbent. The COD removal, using (CuONPs)-based adsorbent, was investigated by varying contact time, masses of the adsorbent, initial COD value and temperatures. The optimum conditions for highest removal percentage were contact time of 120 min, a temperature of 25 °C, pH value of 7.5, and 1 g of adsorbent. The initial COD values used were in the range of 100-700 ppm. The COD percent removal was in the range of 77 to 95%. Freundlich isotherm exhibited the best fitting for the results (R2 = 0.998) with a favorable spontaneous exothermic adsorption process. Based on the calculated normalized deviation value, the modified diffusion model, intra-diffusion, and pseudo-second-order kinetics all showed very good fitting for the adsorption data as indicated by the kinetics study.


Asunto(s)
Nanopartículas , Contaminantes Químicos del Agua , Adsorción , Cobre , Concentración de Iones de Hidrógeno , Cinética , Óxidos , Espectroscopía Infrarroja por Transformada de Fourier , Termodinámica , Aguas Residuales
9.
Viruses ; 13(3)2021 03 23.
Artículo en Inglés | MEDLINE | ID: mdl-33807081

RESUMEN

The emergent human coronavirus SARS-CoV-2 and its high infectivity rate has highlighted the strong need for new disinfection systems. Evidence has proven that airborne transmission is an important route of spreading for this virus. Therefore, this short communication introduces CLODOS Technology®, a novel strategy to disinfect contaminated surfaces. It is a product based on stable and 99% pure chlorine dioxide, already certified as a bactericide, fungicide and virucide against different pathogens. In this study, CLODOS Technology®, by direct contact or thermonebulization, showed virucidal activity against the human coronavirus HCoV-229E at non-cytotoxic doses. Different conditions such as nebulization, exposure time and product concentration have been tested to standardize and optimize this new feasible method for disinfection.


Asunto(s)
Coronavirus Humano 229E/efectos de los fármacos , Desinfectantes/farmacología , Desinfección/métodos , Línea Celular , Compuestos de Cloro/análisis , Compuestos de Cloro/farmacología , Infecciones por Coronavirus/prevención & control , Infecciones por Coronavirus/virología , Desinfectantes/análisis , Desinfección/instrumentación , Humanos , Nebulizadores y Vaporizadores , Óxidos/análisis , Óxidos/farmacología
10.
Bioresour Technol ; 331: 125065, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-33819908

RESUMEN

The co-existence of nitrate, manganese (Mn), and antibiotics are of a wide concern. In this study, a denitrifying and manganese-oxidizing Zoogloea Q7 bacterium was immobilized using polyvinyl alcohol/sodium alginate with sponge cube (PVA/SA@sponge cube) in the reactor. The optimal operation parameters of the bioreactor were explored. Maximum nitrate, Mn(II), and tetracycline (TC) removal efficiencies of 93.00, 72.34, and 57.32% were achieved with HRT of 10 h, pH of 6.5, Mn(II) concentration of 20 mg L-1, and TC of 1 mg L-1, respectively. Fluorescence excitation-emission matrix (EEM) proved that the microorganism in the bioreactor was greatly active. Scanning electron microscope (SEM) images demonstrated that Zoogloea Q7 was commendably immobilized on the novel material. X-ray diffraction (XRD) analysis suggested that the bioprecipitate was mainly composed of MnO2 and MnCO3. Through high-throughput analysis, Zoogloea sp. Q7 was considered to be the dominant bacteria present in the bioreactor.


Asunto(s)
Nitratos , Alcohol Polivinílico , Alginatos , Antibacterianos , Reactores Biológicos , Desnitrificación , Manganeso , Compuestos de Manganeso , Óxidos
11.
Int J Nanomedicine ; 16: 2761-2773, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33880022

RESUMEN

Purpose: The side effects of radiotherapy induced on healthy tissue limit its use. To overcome this issue and fully exploit the potential of radiotherapy to treat cancers, the first-in-class radioenhancer NBTXR3 (functionalized hafnium oxide nanoparticles) has been designed to amplify the effects of radiotherapy. Patients and Methods: Thanks to its physical mode of action, NBTXR3 has the potential to be used to treat any type of solid tumor. Here we demonstrate that NBTXR3 can be used to treat a wide variety of solid cancers. For this, we evaluated different parameters on a large panel of human cancer models, such as nanoparticle endocytosis, in vitro cell death induction, dispersion, and retention of NBTXR3 in the tumor tissue and tumor growth control. Results: Whatever the model considered, we show that NBTXR3 was internalized by cancer cells and persisted within the tumors throughout radiotherapy treatment. NBTXR3 activated by radiotherapy was also more effective in destroying cancer cells and in controlling tumor growth than radiotherapy alone. Beyond the effects of NBTXR3 as single agent, we show that the antitumor efficacy of cisplatin-based chemoradiotherapy treatment was improved when combined with NBTXR3. Conclusion: These data support that NBTXR3 could be universally used to treat solid cancers when radiotherapy is indicated, opening promising new therapeutic perspectives of treatment for the benefit of many patients.


Asunto(s)
Antineoplásicos/uso terapéutico , Hafnio/química , Nanopartículas/química , Neoplasias/radioterapia , Óxidos/química , Animales , Antineoplásicos/farmacología , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Cisplatino/farmacología , Cisplatino/uso terapéutico , Terapia Combinada , Endocitosis/efectos de los fármacos , Humanos , Ratones Desnudos , Nanopartículas/administración & dosificación , Nanopartículas/ultraestructura , Neoplasias/tratamiento farmacológico , Neoplasias/patología , Distribución Tisular/efectos de los fármacos , Resultado del Tratamiento
12.
Gen Dent ; 69(3): 46-51, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33908878

RESUMEN

This study aimed to compare the effects of different combinations of adhesive bases and restorative materials on the fracture strength and mode of maxillary premolars with mesio-occlusodistal (MOD) cavities after mineral trioxide aggregate (MTA) pulpotomy. Ninety-six extracted human maxillary premolars were divided into 8 groups (n = 12). Group 1 (negative control) consisted of intact teeth. In the other teeth, MOD and endodontic access cavities were prepared, and a layer of MTA was placed. Group 2 was left unrestored as the positive control. Group 3 was restored with a glass ionomer cement (GIC) base and amalgam. The remaining groups were restored with a microhybrid composite after application of different bases: 4, resin-modified GIC (RMGIC); 5, zirconia-reinforced GIC (ZRGIC); 6, self-adhesive flowable composite (SAFC); 7, self-adhesive resin cement (SARC); and 8, short fiber-reinforced composite (SFRC). After fracture strength testing via continuous compressive axial loading, the fracture mode was classified as restorable or unrestorable. Data were analyzed using 1-way analysis of variance and post hoc Tamhane tests (P < 0.05). The fracture strength of the negative control group was significantly higher than that of all other groups (P < 0.001). The fracture strengths of groups 2 and 3 were not significantly different (P > 0.05) from each other but were significantly lower (P = 0.002) than those of all composite-restored groups. Group 8 showed a significantly greater fracture strength than group 4 (P < 0.001). Unlike GIC/amalgam, all of the base/composite restoration groups partly restored the strength of pulpotomized premolars. Although their fracture strengths were statistically similar, the fracture modes were more favorable in groups with SAFC or SARC bases than in groups with RMGIC or ZRGIC bases. The SFRC/composite specimens revealed advantages in both fracture strength and fracture mode compared to RMGIC/composite specimens.


Asunto(s)
Fracturas de los Dientes , Diente no Vital , Compuestos de Aluminio , Diente Premolar , Compuestos de Calcio , Resinas Compuestas , Restauración Dental Permanente , Análisis del Estrés Dental , Combinación de Medicamentos , Resistencia Flexional , Humanos , Ensayo de Materiales , Óxidos , Pulpotomía , Silicatos
13.
Int J Oral Maxillofac Implants ; 36(2): 289-294, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33909718

RESUMEN

PURPOSE: The objective of this study was to evaluate the influence of the oxide layer removal procedure using acid on the roughness and internal fit of overcast universal castable long abutments (UCLAs) for a taper connection. MATERIALS AND METHODS: For this, maxillary first premolars were waxed on the plastic sleeve of 15 UCLAs with a premachined interface. The specimens were overcast using the NiCr alloy, and the frameworks were randomly distributed to undergo one of two different oxide layer removal methods: blasting with 100-µm particles of aluminum oxide at 0.60-MPa pressure or bathing for 5 hours in 0.5% hydrofluoric acid. The surface roughness was evaluated by a light interferometer at the subcritical contour of each abutment. Next, the frameworks were attached to the respective analogs for internal fit evaluation. The central cross section of each assembly was exposed, and three regions were visualized by scanning electron microscopy (SEM): taper interface, axial wall, and index region. The premachined base was used as the control. The groups were compared using analysis of variance (ANOVA) and Tukey post hoc test (α = .05). RESULTS: The results showed that acid bathing produced intermediary roughness between premachined and blasted surfaces (P < .05). SEM images showed a sealed interface at the taper region of all groups, despite some irregularities after alumina blasting. Increased discrepancies at the axial wall and index region were found after the alumina blasting procedure (P < .05). CONCLUSION: It was concluded that acid bathing should be used, instead of blasting to remove the oxide layer, to produce a better fit and smoother surface on UCLAs.


Asunto(s)
Pilares Dentales , Óxidos , Óxido de Aluminio , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Propiedades de Superficie
14.
An Acad Bras Cienc ; 93(3): e20190739, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33909753

RESUMEN

Nanotechnology is a field that, over the years, has been growing in several research areas, such as medicine, agriculture and cosmetics, among others. As a result, there is a continuous increase in the production, use and disposal of these materials in the environment. The behaviour and (bio) activity of these materials in the atmosphere, water and soil are not fully studied. Therefore, it is necessary to carry out an analysis of the risks of contamination, as well as the possible effects and impacts of nanoparticles (NPs) on the ecosystem. In an attempt to investigate these effects on plants, the present study aimed to investigate the impact of copper oxide nanoparticles (CuO NPs) on the seed germination process of Sesbania virgata. For this, the Sesbania virgata seeds were subjected to different concentration of CuO NPs (0, 100, 200, 300 and 400 mgL-1) and their germination and development were monitored by optical analysis (thermography and chlorophyll a fluorescence). The results show that the CuO NPs induced a reduction on the maximum emission of chlorophyll a, which was concentration-dependent. The data also showed that CuO NPs promoted an increase in the energy dissipated by non-photochemical pathways and the surface temperature of the seeds. Additionally, our findings revealed that CuO NPs caused a root growth inhibition. In summary, the present study demonstrates, for the first time, that CuO NPs can negatively affect the physiological status and development of the S. virgata plant, by altering the efficiency of the functioning of photosystem II in its initial developmental stage, depending on the concentration of CuO NPs.


Asunto(s)
Fabaceae , Nanopartículas , Sesbania , Clorofila A , Cobre/farmacología , Ecosistema , Germinación , Óxidos
15.
Braz Dent J ; 32(1): 42-47, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33914001

RESUMEN

New methodologies using micro-CT to evaluate solubility besides dimensional and morphological changes of endodontic materials are proposed. However, there is no standardization in the methods. The aim of this study was to assess the effect of different dimensions of test samples on volumetric change evaluation of different endodontic materials. AH Plus, FillCanal and Sealapex root canal sealers, Biodentine, IRM and MTA root-end filling cements were used in the tests. Samples of each material with a thickness of 1.5 mm and different diameters were manufactured: 6.3, 7.75, and 9.0 mm. The samples were scanned in micro-computed tomography (micro-CT) after setting and after 7 days of immersion in distilled water. The volumetric change was evaluated by means of the difference in the total volume of the specimens before and after immersion. Data were submitted to ANOVA and Tukey tests (p<0.05). The size of the samples did not affect the percentage of volumetric change of the materials (p>0.05). All sample sizes had greater volume loss for Sealapex among the sealers and Biodentine for the cements (p<0.05). In conclusion, Biodentine and Sealapex had the highest volume loss after immersion. Samples with 1.5 mm thickness, and diameters ranging between 6.3 and 9.0 mm can be used to assess the stability of endodontic materials using micro-CT without affecting the percentage of volumetric change.


Asunto(s)
Materiales de Obturación del Conducto Radicular , Compuestos de Calcio , Combinación de Medicamentos , Resinas Epoxi , Ensayo de Materiales , Óxidos , Obturación del Conducto Radicular , Microtomografía por Rayos X
16.
Braz Dent J ; 32(1): 53-58, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33914003

RESUMEN

The endodontic revascularization may be an alternative treatment for necrotic immature teeth, however, several treatment steps may cause tooth discoloration. This study evaluated the use of three calcium silicate-based cements with different radiopacifying agents on the color alteration (∆E) of extracted premolars after simulation of revascularization. Forty single rooted extracted premolars were shaped with #1-6 gates Glidden drills, rinsed with sodium hypochlorite, and filled with fresh human blood. Three calcium silicate-based cements with different radiopacifying agents (bismuth oxide - CSBi, calcium tungstate - CSW, and zirconium oxide - CSZr) were applied over the blood clot (n=10). The control group received the application of a temporary zinc oxide-based cement (TFZn) (n=10). ∆E was measured with a spectrophotometer, using the L*a*b* color system of the International Commission on Illumination (CIELab), in different times: prior to the preparation of the access cavity (t0); right after treatment (t1); and after one (t2), two (t3), three (t4) and four (t5) months. The tooth site for color evaluation was standardized by silicon matrix, the color reading was performed 3 times per tooth, and the teeth were stored in 37º water between evaluations. ∆E, whiteness (WID index) and yellowness (b*) were evaluated. Data were subjected to one-way ANOVA and repeated measures ANOVA, followed by Tukey's post hoc test (α=0.05). All groups were similar in ∆E1 (t0-t1). The ∆E was the lowest and constant in the control group. In all evaluation times, CSBi presented the highest ∆E (p<0.01). CSW and CSZr were similar in all evaluated times and presented intermediate ∆E values. WID index from CSBi and CSW presented more distancing from 'white' reference. CSBi presented the greatest decrease in yellowness (b* value). The cement containing bismuth oxide presented the highest color alteration values. All tested calcium silicate-based cements presented clinically perceptible discoloration. Calcium tungstate and zirconium oxide may be used as alternative radiopacifiers to decrease tooth discoloration after endodontic tooth revascularization.


Asunto(s)
Materiales de Obturación del Conducto Radicular , Decoloración de Dientes , Compuestos de Aluminio , Compuestos de Calcio , Cementos Dentales , Combinación de Medicamentos , Humanos , Óxidos , Silicatos
17.
Compend Contin Educ Dent ; 42(2): e1-e4, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33740381

RESUMEN

This case report describes the nonsurgical endodontic management of a distolingual floor perforation in a mandibular first molar using an internal matrix and mineral trioxide aggregate (MTA) cement. The pulp chamber was properly cleaned, and after placement of a synthetic collagen material that served as a barrier at the level of furcation, MTA was used to repair the perforation defect. Root canal treatment was completed and the tooth was restored with a composite restoration followed by a porcelain-fused-to-metal crown.


Asunto(s)
Materiales de Obturación del Conducto Radicular , Cemento de Silicato , Compuestos de Aluminio/uso terapéutico , Calcio , Compuestos de Calcio/uso terapéutico , Cementos Dentales/uso terapéutico , Combinación de Medicamentos , Humanos , Óxidos/uso terapéutico , Materiales de Obturación del Conducto Radicular/uso terapéutico , Silicatos/uso terapéutico
18.
Eur J Paediatr Dent ; 22(1): 19-25, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33719478

RESUMEN

AIM: There is insufficient evidence on the outcome of pulpotomies in carious exposed young permanent molars with newer biomaterials. This study aimed to compare Mineral Trioxide Aggregate (MTA) and Biodentine as pulpotomy materials in carious exposed vital immature mandibular first permanent molars. MATERIALS AND METHODS: Study design: Sixty immature first mandibular permanent molars, with carious exposure were randomly assigned to an MTA or Biodentine group in a split-mouth design. After the amputation of the coronal pulp, the pulp stumps were covered with one of the study materials and coronal restorations placed. Blinded clinical and radiographic evaluations were performed at baseline. Following this there were evaluations at 6, 12 and 18 months where comparisons between and within the two groups were made. RESULTS: A high success was observed in both groups for all outcome measures for clinical success, with no significant difference between them. The mean survival time for the Biodentine and MTA groups was (17.8 and 18 months) with 95% confidence interval (17.4-18.2) and (18 .0-18.0) months respectively. Similarly, there were no significant differences between the Biodentine and MTA groups for radiographic success (P<0.001) with an increase in root length and increasing apical closure observed in both groups. CONCLUSIONS: Both materials were equally effective in the treatment of cariously exposed vital immature mandibular first permanent molars.


Asunto(s)
Materiales de Recubrimiento Pulpar y Pulpectomía , Pulpotomía , Compuestos de Aluminio/uso terapéutico , Compuestos de Calcio , Combinación de Medicamentos , Humanos , Diente Molar/diagnóstico por imagen , Diente Molar/cirugía , Óxidos/uso terapéutico , Materiales de Recubrimiento Pulpar y Pulpectomía/uso terapéutico , Silicatos/uso terapéutico , Resultado del Tratamiento
19.
J Biomed Nanotechnol ; 17(1): 131-148, 2021 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-33653502

RESUMEN

Graphene, including graphene quantum dots, its oxide and unoxidized forms (pure graphene) have several properties, like fluorescence, electrical conductivity, theoretical surface area, low toxicity, and high biocompatibility. In this study, we evaluated genotoxicity (in silico analysis using the functional density theory-FDT), cytotoxicity (human glioblastoma cell line), in vivo pharmacokinetics, in vivo impact on microcirculation and cell internalization assay. It was also radiolabeled with lutetium 177 (177Lu), a beta emitter radioisotope to explore its therapeutic use as nanodrug. Finally, the impact of its disposal in the environment was analyzed using ecotoxicological evaluation. FDT analysis demonstrated that graphene can construct covalent and non-covalent bonds with different nucleobases, and graphene oxide is responsible for generation of reactive oxygen species (ROS), corroborating its genotoxicity. On the other hand, non-cytotoxic effect on glioblastoma cells could be demonstrated. The pharmacokinetics analysis showed high plasmatic concentration and clearance. Topical application of 0.1 and 1 mg/kg of graphene nanoparticles on the hamster skinfold preparation did not show inflammatory effect. The cell internalization assay showed that 1-hour post contact with cells, graphene can cross the plasmatic membrane and accumulate in the cytoplasm. Radio labeling with 177Lu is possible and its use as therapeutic nanosystem is viable. Finally, the ecotoxicity analysis showed that A. silina exposed to graphene showed pronounced uptake and absorption in the nauplii gut and formation of ROS. The data obtained showed that although being formed exclusively of carbon and carbon-oxygen, graphene and graphene oxide respectively generate somewhat contradictory results and more studies should be performed to certify the safety use of this nanoplatform.


Asunto(s)
Grafito , Nanopartículas , Puntos Cuánticos , Supervivencia Celular , Grafito/toxicidad , Humanos , Óxidos , Especies Reactivas de Oxígeno
20.
Environ Sci Process Impacts ; 23(4): 605-620, 2021 Apr 28.
Artículo en Inglés | MEDLINE | ID: mdl-33723564

RESUMEN

Double-stranded ribonucleic acid (dsRNA) molecules are novel plant-incorporated protectants expressed in genetically modified RNA interference (RNAi) crops. Ecological risk assessment (ERA) of RNAi crops requires a heretofore-missing detailed understanding of dsRNA adsorption in soils, a key fate process. Herein, we systematically study the adsorption of a model dsRNA molecule and of two double-stranded deoxyribonucleic acid (DNA) molecules of varying lengths to three soil iron (oxyhydr-)oxides - goethite, lepidocrocite, and hematite - over a range of solution pH (4.5-10), ionic strength (I = 10-100 mM NaCl) and composition (0.5, 1, and 3 mM MgCl2) and in the absence and presence of phosphate (0.05-5 mM) as co-adsorbate. We hypothesized comparable adsorption characteristics of dsRNA and DNA based on their structural similarities. Consistently, the three nucleic acids (NAs) showed high adsorption affinities to the iron (oxyhydr-)oxides with decreasing adsorption in the order goethite, lepidocrocite, and hematite, likely reflecting a decrease in the hydroxyl group density and positive charges of the oxide surfaces in the same order. NA adsorption also decreased with increasing solution pH, consistent with weakening of NA electrostatic attraction to and inner-sphere complex formation with the iron (oxyhydr-)oxides surfaces as pH increased. Adsorbed NA concentrations increased with increasing I and in the presence of Mg2+, consistent with adsorbed NA molecules adopting more compact conformations. Strong NA-phosphate adsorption competition demonstrates that co-adsorbates need consideration in assessing dsRNA fate in soils. Comparable adsorption characteristics of dsRNA and DNA molecules to iron (oxyhydr-)oxides imply that information on DNA adsorption to soil particle surfaces can inform dsRNA ERA.


Asunto(s)
Compuestos de Hierro , Hierro , Adsorción , Compuestos Férricos , Concentración de Iones de Hidrógeno , Minerales , Compuestos Orgánicos , Óxidos , Suelo
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