Effect of aging and cementation systems on the bond strength to root dentin after fiber post cementation

Abstract This study evaluated the effect of aging and cementation of fiber posts using glass ionomer and resin cements on push-out bond strength, failure mode, and resin tag formation. One hundred and twenty bovine incisors were used. After post-space preparation, the specimens were randomly allocated into 12 groups (n = 10) according to the cementation system used: GC - GC Gold Label Luting & Lining); RL - RelyX Luting 2; MC - MaxCem Elite; RU - RelyX U200 and the aging periods (24 hours, 6 months, and 12 months). Slices from the cervical, middle, and apical thirds were obtained and analyzed by push-out bond strength test and confocal laser scanning microscopy. One-way ANOVA and Tukey's post-hoc test was used at a significance level of 5%. For the push-out bond strength test, no differences among GC, RU, and MC in the cervical and middle thirds were observed, regardless of the period of storage (P > 0.05). In the apical third, GC and RU showed similar bond strength but higher than other groups (P > 0.05). After 12 months, GC showed the highest bond strength (P < 0.05). Bond strength to post-space dentin decreased over time, regardless of the cementation system used. Cohesive failure was the most frequent, regardless of the period of storage, cementation system, and post-space third. Tag formation was similar among all groups. After 12 months, GC showed the highest bond strength values.

Resumo Avaliar o efeito do envelhecimento e sistemas de cimentação usando ionômero de vidro e cimentos resinosos na resistência de união à dentina após a cimentação do pino de fibra. Cento e vinte incisivos bovinos foram utilizados. Após o preparo do pós-espaço, os corpos de prova foram distribuídos aleatoriamente em 12 grupos (n = 10) de acordo com o período de envelhecimento (24 horas, 6 meses e 12 meses) e o sistema de cimentação utilizado: GC - cimento de ionômero de vidro (GC Gold Label Cimentação e Revestimento); RL - RelyX Luting 2; MC - MaxCem Elite; RU - RelyX U200. Cortes dos terços cervical, médio e apical foram obtidos e analisados por teste de resistência de união push-out e microscopia confocal de varredura a laser. ANOVA one-way e teste de Tukey foi usado a um nível de significância de 5%. Para o teste de resistência de união, não foram observadas diferenças entre GC, RU e MC nos terços cervical e médio, independentemente do período de armazenamento (P > 0,05). No terço apical, GC e RU apresentaram resistência de união semelhante, porém superior aos demais grupos (P > 0,05). Após 12 meses, o GC apresentou a maior resistência de união (P < 0,05). A resistência de união à dentina no espaço para pino diminuiu ao longo do tempo, independentemente do sistema de cimentação utilizado. A formação de tags foi semelhante entre todos os grupos. Após 12 meses, o GC apresentou os maiores valores de resistência de união.

Comparison of Sealing Ability of MTA and Retroplast as Root End Filling Materials Evaluated Under a Stereomicroscope Using Rhodamine B Dye: An In vitro Study

Aim: The aim of the study was to compare the sealing ability of Mineral Trioxide Aggregate (MTA) and Retroplast as root end filling materials using the Rhodamine B dye penetration method in vitro. Methodology: Forty freshly extracted human single?rooted teeth were randomly divided into two groups of 20 teeth each, and standard root?end cavities were prepared in all teeth. The cavities were filled with MTA and Retroplast in groups 1 and 2, respectively. The specimens were then stored in 1% Rhodamine B dye for a week, following which the dye penetration with all samples was analysed under a stereomicroscope and scored according to Tronstad’s criteria. The observations were compared with Chi square test at a 0.220 level of significance. Results: 5% of the samples in both the groups showed no significant leakage. The leakage was deeper with the Retroplast group than with the MTA group; however, there was no statistically significant difference between the two groups. Conclusion: Both MTA and Retroplast are similar in their sealing potential as root?end cavity fillings with Retroplast reporting slightly deeper microleakage than MTA within the limits of the present study.

Investigation of Skin Irritation of Essential Oils from Interior-warming Medicines / 中国实验方剂学杂志

Objective:To investigate the skin irritation of essential oils(EOs) extracted from interior-warming medicines. Method:Three EOs from interior-warming medicines(Cinnamomi Cortex, Caryophylli Flos and Alpiniae Officinarum Rhizoma) were selected as research objects.The in vitro skin cytotoxicity and in vivo skin irritation of these EOs were determined and compared.Moreover, the skin irritation was also predicted by the novel skin test panels. Result:Toxicity of these three EOs to human skin fibroblasts(HSF) was significantly different, half-inhibitory concentration(IC50) values of EOs from Cinnamomi Cortex, Alpiniae Officinarum Rhizoma and Caryophylli Flos were (11.16±0.28), (53.33±1.71), (226.70±17.61) mg·L-1, respectively.However, in vivo skin irritation evaluation showed that the local toxicity of these three EOs was in the order of EO of Cinnamomi Cortex > EO of Caryophylli Flos > EO of Alpiniae Officinarum Rhizoma. The evaluation results of skin test panels for these three EOs were in accordance with the results of in vivo skin irritation evaluation. Conclusion:Toxicity of these three EOs against skin cells in vitro is inconsistent with their in vivo skin irritation. Skin test panels are expected to be able to accurately predict in vivo skin irritation of EOs instead of cytotoxicity evaluation.

Facile Solvothermal Synthesis of Reduced Graphene Oxide-BiPO4 Nanocomposite with Enhanced Photocatalytic Activity / 分析化学

Reduced graphene oxide-BiPO4 ( RGO-BiPO4 ) nanocomposite was synthesized successfully via a one-pot solvothermal method using graphene oxide and bismuth nitrate as precursors and glycerin as solvent at 200℃ for 1 h. The morphology and structure of as-prepared nanocomposite were characterized by SEM, TEM, XRD, XPS, SERS and UV-Visible spectrum. The photocatalytic activity of the nanocomposite was evaluated by the photodegradation of Rhodamine B ( RhB) dye under UV irradiation and it was found that RGO-BiPO4 nanocomposite possessed higher photocatalytic activity than that of pure BiPO4 . RhB could be decomposed 87. 5% within 2 h. Under the same conditions, only 45. 7% of the RhB dye could be decomposed by BiPO4 . The enhancement of photocatalytic activity could be attributed to the effective charge separation due to the electron-accepting and transporting properties of graphene.

Stable Cu2 O@Au for Accurate and Rapid Surface Enhancement Raman Scattering Analysis of Rhodamine B / 分析化学

A simple and efficient method for fabricating a novel surface-enhanced Raman scattering ( SERS) substrate with good reproducibility and high SERS activity was reported. Cu2 O was prepared by mixing CuCl2 ·2H2 O with ascorbic acid, which was then used as the templates for depositing of gold nanoparticles ( AuNPs) on their surfaces, forming Cu2 O@ Au with heterostructures. Transmission electron microscopy, scanning electron microscopy and X-ray diffraction observation revealed that Cu2 O had polyhedral structure and smooth surface, and AuNPs were closely deposited on the surface of Cu2 O. It was used as SERS substrate for detection of Rhodamine B with linear detection range of 1 × 10-2-5 × 10-6 mol/L, and detection limit of 3 ×10-7 mol/L. Cu2 O@Au showed good chemical stability, remained stable in acid, PBS and river samples, and could be used in the SERS detection of target in water sample.

Based on in vivo fluorescence imaging technology, to extablish a fluorescence modification method for amphipathic block polymers / 药学学报

Rhodamine B (RhB) was used to decorate an amphipathic block polymers (β-CD-[P(AA-co-MMA)-b-PVP]4) in this study. First, after activated by 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, rhodamine B was marked with hydroxyethyl methacrylate (HEMA) through ester exchange reaction. Second, the labeled amphipathic block polymers (β-CD-[P(AA-(HEMA-RhB)-MMA)-b-PVP]4) were synthesized after polymerization reaction of double bones between RhB-HEMA and other reactants. Finally, the structure of product was measured by FT-IR spectra and fluorospectro photometer (FLUORO). The critical micelle concentration of RhB-labeled and unlabeled amphipathic block polymers were 4.96×10-3, 5.09×10-3 mg·L-1, respectively, indicating no change of their micellization behavior. In vivo tissue distribution and whole-body fluorescent imaging were studied by vinpocetine (VP)-loaded polymeric micelles which were prepared through a solvent evaporation method. Compared to the result of in vivo tissue distribution and whole-body fluorescence imaging, a similar bio-distribution behavior of VP-loaded polymeric micelles was found. Those proved the successful fluorescence modification with a labeling yield of 4.13%. With in vivo fluorescence imaging technology, we established a fluorescence method for modification of amphipathic block polymers.

Analytical method to evaluate chelating capacity of constituents in decoction of Chinese materia medica with free iron ions / 中草药

Objective: To establish the in vitro screening method for determining what kinds of Chinese materia medica (CMM) and which main constituents in the medicine used for the treatment of Alzheimer's disease, Parkinson's disease, and osteoporosis can chelate with free iron ions (Fe3+) and evaluating the chelating strength. Methods: Based on the catalytic effect of Fe3+ on the spirolactam (nonfluorescence) to ring-open amide reaction (fluorescence), the catalytic spectrophotometric method was established to determine the free Fe3+ in the decoction of CMM, by adding a certain amount of iron ion and determinig the chelating level to evaluate the chelating strength of the constituents in CMM. Results: The chelating strength of kidney-tonifying CMM is stronger. The catalytic spectrophotometric method could be used to determine the free Fe3+ in the decoction of CMM and the linearity was good in the range of 1.68-22.4 mg/L, r = 0.999 0. The average recovery was between 90.45% and 104.11% with RSD < 5%. Conclusion: This method can be used to evaluate the chelating capacity of constituents in CMM with Fe3+.

Equilibrium and kinetic studies of methylene blue and rhodamineb onto prepared activated kaza’s carbons.

Three Activated Kaza’s Carbons viz. NPTC, NLLC andNCC, are prepared from some Bio- Materials – Phaseolus trilobus, Leucena leucocephala and Casurina. These carbonsare used to adsorb dyes Methylene blue and Rhodamine B from aqueous solution. Adsorption equilibrium data and kinetic processes were studied. The Langmuir isotherm provides the best correlation for the experimental data, where as Temkin and Dubinin – Radushkevich (D-R) isotherms also fit to the experimental data. In the kinetic studies the best fit Model was assessed by the squared some of errors (SSE) values. Adsorption of dyes, Methylene Blue ( MB ) and Rhodamine B ( RB ) ,on to adsorbents could be described by pseudosecond order equation. The adsorption process has good co-ordinance with pore diffusion and Elovich equations.

Influência da estratificação térmica no volume útil e no comportamento hidrodinâmico de lagoa de estabilização: determinação experimental e teórica / Influence of thermal stratification in useful volume and in hydrodinamic behavior of stabilization pond: theoretical and experimental evaluation

Lagoas de estabilização localizadas em regiões com variações elevadas de temperatura ao longo do dia tendem a apresentar estratificação térmica, um fenômeno que altera o volume útil da lagoa. Neste trabalho, apresentam-se resultados experimentais obtidos em duas lagoas, facultativa e maturação, construídas na região central do estado de São Paulo. O acompanhamento do perfil de temperatura mostrou a ocorrência de estratificação térmica com ciclo nictimeral nas duas lagoas. Os ensaios hidrodinâmicos indicaram comportamento semelhante ao de reatores com mistura completa, com zonas mortas, volume útil de aproximadamente 60 por cento na lagoa facultativa e 30 por cento na lagoa de maturação. Os experimentos corroboraram os resultados teóricos obtidos com o modelo matemático para previsão da estratificação térmica.

Stabilization ponds located in places that present high temperature variations along the day have a tendency to present thermal stratification, a phenomenon that changes the useful volume of the pond. This paper presents experimental results from two stabilization ponds, facultative and maturation, built in the central area of the state of São Paulo, Brazil. The observation of the temperature profile showed the occurrence of thermal stratification with the nictimeral cycle in both ponds. Hydrodynamic tests showed a pattern that resembles the behavior of complete mixing reactors with dead zones, resulting in useful volumes close to 60 percent for the facultative pond and 30 percent for the maturation pond. The experiments confirm the theoretical results obtained based on a mathematical model to predict thermal stratification.

Determination of acyclovir and gancyclovir using flow-injection chemiluminescence method / 西安交通大学学报(医学版)

Objective To develop a new flow-injection chemiluminescence(FI-CL) method for the determination of acyclovir and gancyclovir by using the CL system of Ce(IV)-Rhodamine B.Methods The redoxreaction of Ce(IV) and acyclovir/gancyclovir in H2SO4 medium could generate CL signal.Rhodamine B could obviously sensitize this signal,and the CL intensity was proportional to the concentration of acyclovir and gancyclovir.Therefore,a new FI-CL method has been described for the determination of acyclovir and gancyclovir.Results For acyclovir,the determination range was 3.0?10-5g/L-7.0?10-2g/L,with 1.56?10-5g/L as its determination limit.During 11 repeated measurements for 1.0?10-3g/L acyclovir,the relative standard deviation was 2.08%.For ganciclovir,the determination range was 5.0?10-5g/L-7.0?10-2g/L,with 2.35?10-5g/L as its determination limit.The relative standard deviation was 2.83%,with 11 repeated measurements of 1.0?10-3g/L ganciclovir.Conclusion This method has broad linear range,high sensitivity,and convenience and speediness,it therefore,can be successfully used to determine the content of ganciclovir in injections.