The effect of adding ytterbium trifluoride on the radiopacity, compressive strength, setting time and bioactivity of biodentine: an in vitro study / Efeito da adição de trifluoreto de itérbio na radiopacidade, resistência à compressão, tempo de presa e bioatividade da biodentina: estudo in vitro

Objective: This study aimed to evaluate the radiopacity, compressive strength, setting time and bioactivity of Biodentine after modification with Ytterbium Tri-Fluoride (YbF3) in three different concentrations. Material and Methods: Radiopacity was determined using the equivalence in millimeters of aluminum (mm Al) from digital radiographs. Compressive strength was evaluated using a universal testing machine. The initial and final setting times were evaluated using Gillmore needle. The bioactive potential was evaluated using the environmental scanning electron microscope (ESEM) connected with Energy Dispersive X-ray analysis (EDX) and X-ray Diffractometer (XRD) at three different time intervals. pH was measured using a pH-meter. Data were analyzed using one-way ANOVA followed by Tukey's post hoc tests (P≤ 0.05). Results: Radiopacity of Biodentine with 2.5%, 5% and 7.5% YbF3 was significantly higher than unmodified Biodentine (P ≤ 0.05). Unmodified Biodentine showed the highest mean compressive strength values compared to all other groups (p≤ 0.05). The addition of YbF3 to Biodentine has extended the final setting time except for the 2.5% YbF3 group that showed no significant difference compared to the control. All groups showed an alkaline pH at 28 days, ESEM coupled with EDX analysis showed evidence of dense globules of calcium phosphate on the surface indicating enhancement of bioactivity. Conclusion: 2.5% YbF3 can be a promising radiopacifying agent to Biodentine with improvement in radiopacity, bioactive potential and maintaining the setting time and compressive strength at acceptable level as indicated by the ISO standards (AU)

Objetivo: O estudo buscou avaliar a radiopacidade, resistência à compressão, tempo de presa e bioatividade da Biodentina modificada por Trifluoreto de itérbio (YbF3). Materiais e Métodos: YbF3 foi incorporado ao pó de Biodentina e dividido em 4 grupos (X0, X1, X2 e X3) de acordo com a concentração de YbF3; 0%, 2.5%, 5% e 7.5% do peso, respectivamente. Os espécimes foram preparados para cada experimento com um total de 40 espécimes para cada teste (n=10 por grupo). A radiopacidade foi determinada através do uso equivalente em milímetros de alumínio. A resistência a compressão foi avaliada através do uso de uma máquina de teste universal. O tempo inicial e final foi avaliado através de uma agulha de Gillmore. O potencial bioativo foi avaliado através do Microscópio Eletrônico de Varredura (ESEM), conectado com a análise de espectroscopia de raios X por energia dispersiva (EDX) e difração de raio X (DRX). O pH foi mensurado através do uso de um pHmetro. Os dados foram analisados pelo ANOVA seguido do Test Tukey. Resultados: A radiopacidade nos grupos X1, X2 e X3 foi significantemente maior do que no grupo X0. O grupo X0 mostrou a maior resistência à compressão comparado com os outros grupos. A adição de YbF3 a Biodentina excedeu o tempo final exceto pelo grupo X1, que não apresentou diferença estatística significante quando comparado com o grupo X0. Todos os grupos apresentaram um pH alcalino com 28 dias. ESEM com análise EDX mostrou evidência de densos glóbulos de fosfato de cálcio na superfície, indicando uma melhora na bioatividade. Conclusão: 2.5% YbF3 é um promissor radiopacificador para Biodentina, que aumentou a radiopacidade e potencial bioativo enquanto manteve o tempo definido e a resistência à compressão em níveis aceitáveis como indica a norma ISO.(AU)

Ytterbium oxide as radiopacifier of calcium silicate-based cements. physicochemical and biological properties

Abstract This study evaluated physicochemical properties, cytotoxicity and bioactivity of MTA Angelus (MTA), calcium silicate-based cement (CSC) and CSC with 30% Ytterbium oxide (CSC/Yb2O3). Setting time was evaluated using Gilmore needles. Compressive strength was evaluated in a mechanical machine. Radiopacity was evaluated using radiographs of materials and an aluminum scale. Solubility was evaluated after immersion in water. Cell viability was evaluated by means of MTT assay and neutral red staining, and the mineralization activity by using alkaline phosphatase activity and Alizarin Red staining. The data were submitted to ANOVA, Tukey and Bonferroni tests (5% significance). The bioactive potential was evaluated by scanning electron microscopy. The materials presented similar setting time. MTA showed the lowest compressive strength. MTA and CSC/Yb2O3 presented similar radiopacity. CSC/Yb2O3 showed low solubility. Saos-2 cell viability tests showed no cytotoxic effect, except to 1:1 dilution in NR assay which had lower cell viability when compared to the control. ALP at 1 and 7 days was similar to the control. MTA and CSC had greater ALP activity at 3 days when compared to control. All the materials present higher mineralized nodules when compared with the control. SEM analysis showed structures suggesting the presence of calcium phosphate on the surface of materials demonstrating bioactivity. Ytterbium oxide proved to be a properly radiopacifying agent for calcium silicate-based cement since it did not affected the physicochemical and biological properties besides preserving the bioactive potential of this material.

Resumo Este estudo avaliou as propriedades físico-químicas, citotoxicidade e bioatividade do MTA Angelus (MTA), cimento à base de silicato de cálcio (CSC) e CSC com 30% de óxido de itérbio (CSC/Yb2O3). O tempo de presa foi avaliado usando agulhas Gilmore. A resistência à compressão foi avaliada em uma máquina mecânica. A radiopacidade foi avaliada utilizando radiografias dos materiais e uma escala de alumínio. A solubilidade foi avaliada após imersão em água. A viabilidade celular foi avaliada por meio do ensaio MTT e coloração de vermelho neutro (NR), e a atividade de mineralização por meio da atividade da fosfatase alcalina e a coloração com Vermelho de Alizarina. Os dados foram submetidos aos testes ANOVA, Tukey e Bonferroni (5% de significância). O potencial bioativo foi avaliado por microscopia eletrônica de varredura. Os materiais apresentaram tempo de presa semelhante. O MTA mostrou menor resistência à compressão. MTA e CSC/Yb2O3 apresentaram radiopacidade semelhante. CSC/Yb2O3 apresentou menores valores de solubilidade. A viabilidade celular realizada pelos ensaios de MTT e NR não revelaram efeitos ctotóxicos em todas as diluições, exceto na diluição 1:1 no NR, o qual mostrou baixa viabilidade celular (p<0.05) em todos materiais testados quando comparado ao controle. A atividade de ALP em 1 e 7 dias foi similar ao controle (p>0.05). MTA e CSC tiveram significante aumento na atividade de ALP aos 3 dias quando comarados ao controle (p>0.05). Todos os materiais apresentaram grande produção de nódulos mineralizados quando comparados ao controle (P<0.05). A análise da SEM mostrou estruturas que sugerem a presença de depósitos de fosfato de cálcio na superfície dos materiais demonstrando bioatividade. O Yb2O3 mostrou ser um agente radiopacificador adequado em cimentos à base de silicato de cálcio uma vez que não afetou as propriedades físico-químicas e biológicas e ainda preservou o potencial bioativo desse material.

Influence of radiopaque fillers on physicochemical properties of a model epoxy resin-based root canal sealer

Objective: To verify the influence of radiopaque fillers on an epoxy resin-based sealer. Material and Methods: Experimental sealers were formulated by adding 20%, 40%, 60%, 80%, 100% and 120% of calcium tungstate, ytterbium trifluoride or barium sulphate by weight to an epoxy-resin-base. Setting time, flow, film thickness, radiopacity, sorption, solubility, pH and push-out bond strength were evaluated. Results: The setting time ranged from 373 to 612.66 min, the flow varied from 13.81±0.49 to 22.49±0.37 mm, and the film thickness ranged from 16.67±5.77 to 33.33±11.54 µm. The lowest pH was 5.47±0.53, and the highest was 6.99±0.03. Radiopacity varied from 0.38±0.04 to 2.57±0.21 mmAl and increased with the amount of filler. Calcium tungstate sealers had a higher sorption and solubility than other sealers. There was no significant difference in the push-out bond strength among the fillers at the 120% concentration. CONCLUSION: The inorganic fillers evaluated and their concentrations affect the physicochemical properties of an epoxy resin-based root canal sealer. .

A differential proteomic study on the influence of ytterbium citrate on HepG2 cells / 中华预防医学杂志

<p><b>OBJECTIVE</b>To explore the effects of ytterbium citrate on human liver carcinoma HepG2 cell line and the potential mechanisms.</p><p><b>METHODS</b>The HepG2 cells were cultured with DMEM medium and divided into different groups in the following media, in serum-free medium as control, different concentration (0.01 - 5.00 mmol/L) [YbCit(2)](3-)+serum-free medium as treatment group, MTT assay was used to measure the viability of the cells; 2.00 mmol/L [YbCit(2)](3-)+serum-free medium was used as treatment group, and Hoechst 33258 staining was used to detect apoptosis in HepG2 cells. Differential proteomic analysis, assay of intracellular H(2)O(2) levels and mitochondrial transmembrane potential were performed to study the effects of [YbCit(2)](3-) on HepG2 cells and the potential mechanisms.</p><p><b>RESULTS</b>The data showed that 72 h treatment of [YbCit(2)](3-) at 2.00 - 5.00 mmol/L significantly inhibited cell proliferation, and the IC(50) was (2.46 ± 0.23) mmol/L. After treatment with 2.00 mmol/L [YbCit(2)](3-) for 48 h and 72 h, Hoechst 33258 staining demonstrated that [YbCit(2)](3-) induced significantly increased apoptosis in HepG2 cells. After treatment with 2.00 mmol/L [YbCit(2)](3-) for 72 h, two dimensional gel electrophoresis and MALDI-TOF mass spectrometry analysis revealed 14 differentially expressed proteins between [YbCit(2)](3-)-treated cells and the control cells. These proteins mainly included cofilin1, peroxiredoxin6, S100 calcium-binding protein A6, and proteasome 26S non-ATPase subunit 13 isoform 3 and so on. These proteins played important roles in the processes of anti-apoptosis, oxidation reduction, cell proliferation and protein degradation. The mitochondrial membrane potential were investigated, the results showed the red and green fluorescence ratio was 2.45 ± 0.28 in the control group, 1.56 ± 0.23 in 24 h group, 1.16 ± 0.18 in 48 h group, compared with the control, the differences were significant (F = 23.97, P = 0.001). The results of H(2)O(2) detection showed the fluorescence intensity was 20.00 ± 2.08 in the control group, 40.00 ± 5.50 in 24 h group, and 48.00 ± 2.03 in 48 h group, compared with the control, the differences were significant (F = 48.40, P = 0.000). The results indicated a significant reduction in mitochondrial transmembrane potential and significant increase in H2O2 generation were observed in [YbCit(2)](3-)-treated cells.</p><p><b>CONCLUSION</b>These results suggested that [YbCit(2)](3-) could induce apoptosis of HepG2 cells through the mechanisms involving oxidative stress and mitochondrial dysfunction.</p>

A computer program for single-injection tracer clearance from one, two, or many blood samples

A computer program based on a Bayesian statistical model has been developed for calculating tracer clearance from any number of plasma samples drawn at arbitrary time intervals. Bayesian prior parameters were calculated from clinical data for Tc99m-MAG3, Tc99m-EC, I131-OIH, Tc99m-DTPA, and Yb169-DTPA and then used to calculate clearance from prospective data. Clearance estimates using only one or two plasma samples were found to closely approximate the results of using multiple samples. When only one or a few samples are available, the program supplements the observed data by a Bayesian prior probability distribution (based on prior clinical measurements) to achieve agreement with multisample clearance. When many points are available, the observed data overwhelm the prior probability, and results approach those of conventional curve fitting but with less sensitivity to bad data points and less risk of fitting failure.

Níveis de proteínas totais e o desenvolvimento embrionário de ovos de ouriço do mar (Lytechinus variegatus) tratados com YbC13

Foram estudados os níveis de proteínas totais e o desenvolvimento embrionário de ovos de ouriço do mar (Lytechinus variegatus) tratados com cloreto de itérbio na concentraçäo de 25 migrongrama/ml em água do mar durante uma hora. Após o tratamento os ovos se desenvolveram durante 24 horas, quando os níveis de proteínas totais foram determinados e as modificaçöes morfológicas foram examinadas, bem como o sincronismo do desenvolvimento embrionário.