Avaliação da sorção e solubilidade de água em cimentos de ionômero de vidro com e sem agente de proteção / Evaluation of water sorption and solubility in glass ionomer cements with and without protective agent

Objetivo: Avaliar o efeito de um protetor de superfície na sorção e solubilidade de cimentos de ionômero de vidro. Materiais e Métodos: Quatro materiais foram selecionados: ionômero modificado por resina encapsulado (Riva Light Cure); modificado por resina pó/líquido (Vitremer); convencional encapsulado (Equia Forte) e convencional pó/líquido (Fuji IX). Foram confeccionados 20 espécimes de cada, sendo metade com proteção superficial do Equia Forte Coat. As amostras foram mantidas em estufa a 37°C em repouso por 5 dias. Em seguida, esses foram pesados em intervalos de 24 horas. A espessura e o diâmetro foram medidos com um paquímetro digital para o cálculo do volume. Novas pesagens foram realizadas para a obtenção da massa intermediária. Em seguida, as amostras foram mantidas em repouso por 5 dias a 37°C e realizada nova pesagem. Resultados: Os dados obtidos de sorção e solubilidade foram submetidos à análise de variância (ANOVA dois fatores, material e protetor de superfície) e teste Tukey ( =0,05). Para sorção, houve diferença significativa apenas para o fator material (p<0,05), Vitremer > Equia Forte > Riva Light Cure > Fuji IX. O ionômero Fuji IX apresentou os menores valores de sorção, diferindo significativamente dos demais materiais, independentemente do uso do protetor superficial. Não houve diferença significativa para o fator proteção de superfície (p>0,05). Para solubilidade não houve diferença significativa no fator material, protetor de superfície ou interação material*protetor. Conclusão: O uso do protetor superficial não influenciou nos valores de sorção e solubilidade dos ionômeros avaliados e o ionômero convencional Fuji IX apresentou menores taxas de sorção.

Objective: evaluate the effect of a surface coating agents on the sorption and glass ionomer cements solubility. Materials and Methods: Four materials were selected: Encapsulated resin-modified ionomer (Riva Light Cure); Powder/liquid Encapsulated resin-modified (Vitremer); Encapsulated conventional (Equia Forte) and powder/ liquid conventional (Fuji IX). Twenty samples of each were made, half with surface protection of Equia Forte Coat. The samples were kept in an oven for 5 days. These were then weighed at 24-hour intervals. The thickness and diameter were measured using a digital caliper to calculate their volume. New weightings were performed to obtain the intermediate mass. Then, the samples were kept at rest for 5 days and weighed again. Results: The sorption and solubility data obtained were subjected to analysis of variance (two-way ANOVA, material and surface coating agents) and Tukey test ( =0.05). For sorption, there was a significant difference only for the material factor (p<0.05), Vitremer > Equia Forte > Riva Light Cure > Fuji IX. The Fuji IX ionomer showed the lowest sorption values, differing significantly from the other materials, regardless of the use of surface coating agents. There was no significant difference for the surface protection factor (p>0.05). For solubility there was no significant difference for the material factor, surface coating agents or material*surface coating agent interaction. Conclusion: The use of surface coating agents did not influence the sorption and solubility values of the evaluated ionomers and the conventional Fuji IX ionomer showed lower sorption rates.

Effect of rewetting solutions on micropush-out dentin bond strength of new bioceramic endodontic material

Abstract To evaluate the influence of rewetting solutions on bond strength to root dentin of conventional gutta-percha (GP) or niobium phosphate glass-based gutta-percha (GNb) associated with a bioceramic sealer. The root canals of 80 human mandibular premolars were prepared using nickel-titanium instruments and irrigation with sodium hypochlorite and EDTA. The teeth were randomly divided into four groups according to the gutta-percha used: GNb or GP associated with EndoSequence BC Sealer (BC) and the solution for rewetting dentin before filling (distilled water; phosphate buffer saline solution - PBS; simulated body fluid - SBF; or no solution). The root canals were filled with a single cone using warm vertical condensation. Micropush-out bond strengths associated with the filling materials in slices from middle root thirds was determined 30 days after root filling. The failure mode was analyzed with stereoscopic lens. The data were statistically analyzed by two-way ANOVA and Holm-Sidak test (p < 0.05). There was significant difference in the types of gutta-percha (p < 0.001) and in the different rewetting solutions (p = 0.003). The interaction between gutta-percha and rewetting solutions was not significant (p = 0.53). The SBF solution provided an increase in bond strength for both gutta-percha solutions. The GNb+BC (3.42 MPa) association increased bond strength when compared with GP+BC (2.0 MPa). The use of SBF as a dentin rewetting solution increased bond strength in the groups studied. Association of GNb with bioceramic sealer was beneficial, increasing the bond strength to dentin when compared with the association with GP.

Simultaneous determination of naphazoline hydrochloride, chlorpheniramine maleate and methylene blue in their ternary mixture

Validated spectrophotometric and chemometric methods were developed for determination of Naphazoline Hydrochloride [NAP], Chlorpheniramine maleate [CLO] and Methylene blue [MB] in their ternary mixture. Method A was a spectrophotometric method, where NAP and MB were determined using second derivative [D2] spectrophoto metric method using the peak amplitudes at 299 nm and 337 nm for NAP and MB respectively, while CLO was determined using second derivative ratio [DD[2]] spectrophotometric method using the peak amplitude at 276.6 nm. Method B used the chemometric techniques; principal component regression [PCR] and partial least squares [PLS] for determination of NAP, CLO and MB using the information contained in the absorption spectra of their ternary mixture solutions. The proposed methods have been successfully applied for the analysis of NAP, CLO and MB in their pharmaceutical formulation and the obtained results were statistically compared with the reported methods

Methylparaben concentration in commercial Brazilian local anesthetics solutions

OBJECTIVE: To detect the presence and concentration of methylparaben in cartridges of commercial Brazilian local anesthetics. MATERIAL AND METHODS: Twelve commercial brands (4 in glass and 8 in plastic cartridges) of local anesthetic solutions for use in dentistry were purchased from the Brazilian market and analyzed. Different lots of the commercial brands were obtained in different Brazilian cities (Piracicaba, Campinas and São Paulo). Separation was performed using high performance liquid chromatography (HPLC) with UV-Vis detector. The mobile phase used was acetonitrile:water (75:25 - v/v), pH 4.5, adjusted with acetic acid at a flow rate of 1.0 ml.min-1. RESULTS: When detected in the solutions, the methylparaben concentration ranged from 0.01% (m/v) to 0.16% (m/v). One glass and all plastic cartridges presented methylparaben. CONCLUSION: 1. Methylparaben concentration varied among solutions from different manufacturers, and it was not indicated in the drug package inserts; 2. Since the presence of methylparaben in dental anesthetics is not regulated by the Brazilian National Health Surveillance Agency (ANVISA) and this substance could cause allergic reactions, it is important to alert dentists about its possible presence.

Antioxidant activity by DPPH assay of potential solutions to be applied on bleached teeth

The aim of this study was to assess, using the DPPH assay, the antioxidant activity of several substances that could be proposed to immediately revert the problems caused by bleaching procedures. The percentage of antioxidant activity (AA percent) of 10 percent ascorbic acid solution (AAcidS), 10 percent ascorbic acid gel (AAcidG), 10 percent sodium ascorbate solution (SodAsS), 10 percent sodium ascorbate gel (SodAsG), 10 percent sodium bicarbonate (Bicarb), Neutralize® (NE), Desensibilize® (DES), catalase C-40 at 10 mg/mL (CAT), 10 percent alcohol solution of alpha-tocopherol (VitE), Listerine® (LIS), 0.12 percent chlorhexidine (CHX), Croton Lechleri (CL), 10 percent aqueous solution of Uncaria Tomentosa (UT), artificial saliva (ArtS) and 0.05 percent sodium fluoride (NaF) was assessed in triplicate by 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) free radical assay. All substances exhibited antioxidant activity, except for CL. AAcidS, AAcidG and VitE exhibited the highest AA percent (p<0.05). On the contrary, CHX, NE, LIS and NaF showed the lowest AA percent (p<0.05). In conclusion, AAcidS, AAcidG, SodAsS, SodAsG and VitE presented the highest antioxidant activity among substances tested in this study. The DPPH assay provides an easy and rapid way to evaluate potential antioxidants.

O objetivo deste estudo foi avaliar, por meio do DPPH, a atividade antioxidante de substâncias que poderiam ser propostas para reverter de imediato os problemas causados pelos procedimentos de clareamento. A porcentagem de atividade antioxidante (AA por cento) da solução de acido ascórbico 10 por cento (AAcidS), gel de ácido ascórbico a 10 por cento (AAcidG), solução de ascorbato de sódio 10 por cento (SodAsS), gel de ascorbato de sódio 10 por cento (SodAsG), bicarbonato de sódio 10 por cento (Bicarb), Neutralize® (NE), Desensibilize® (DES), catalase C-40 10 mg/mL (CAT), solução alcoólica 10 por cento de alfa-tocoferol (VitE), Listerine® (LIS), clorexidina 0,12 por cento (CHX), CrotonLechleri (CL), solução aquosa 10 por cento de Uncaria Tomentosa (UT), saliva artificial (ArtS) e fluoreto de sódio 0,05 por cento (NaF) foi avaliada em triplicata pelo teste de radicais livres 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH). Todas as substâncias apresentaram atividade antioxidante, exceto a CL. AAcidS, AAcidG e VitE mostraram os maiores valores de AA por cento (p<0,05). Por outro lado, CHX, NE, LIS e NaF mostraram os valores mais baixos de AA por cento (p<0,05). Em conclusão, AAcidS, AAcidG, SodAsS, SodAsG e VitE apresentaram os mais altos valores de atividade antioxidante entre as substâncias testadas. O teste DPPH é um método rápido e fácil para avaliar o potencial antioxidante.

Effect of conventional and experimental gingival retraction solutions on the tensile strength and inhibition of polymerization of four types of impression materials

In the present study, two types of tests (tensile strength test and polymerization inhibition test) were performed to evaluate the physical and chemical properties of four impression materials [a polysulfide (Permlastic), a polyether (Impregum), a condensation silicone (Xantopren) and a polyvinylsiloxane (Aquasil) ,3; when polymerized in contact with of one conventional (Hemostop) and two experimental (Vislin and Afrin) gingival retraction solutions. For the tensile strength test, the impression materials were mixed and packed into a steel plate with perforations that had residues of the gingival retraction solutions. After polymerization, the specimens were tested in tensile strength in a universal testing machine. For the polymerization inhibition test, specimens were obtained after taking impressions from a matrix with perforations that contained 1 drop of the gingival retraction solutions. Two independent examiners decided on whether or not impression material remnants remained unpolymerized, indicating interference of the chemical solutions. Based on the analysis of the results of both tests, the following conclusions were reached: 1. The tensile strength of the polysulfide decreased after contact with Hemostop and Afrin. 2. None of the chemical solutions inhibited the polymerization of the polysulfide; 3. The polyether presented lower tensile strength after polymerization in contact with the three gingival retraction agents; 4. The polyether had its polymerization inhibited only by Hemostop; 5. None of the chemical solutions affected the tensile strength of the condensation silicone; 6. Only Hemostop inhibited the polymerization of the condensation silicone; 7. The polyvinylsiloxane specimens polymerized in contact with Hemostop had significantly lower tensile strength; 8. Neither of the chemical solutions (Afrin and Vislin) affected the tensile strength of the polyvinylsiloxane and the condensation silicone; 9. Results of ...

Influence of method and period of storage on the microtensile bond strength of indirect composite resin restorations to dentine

This study evaluated the influence of the method and period of storage on the adhesive bond strength of indirect composite resin to bovine dentin. Ninety bovine incisors were stored in three different solutions: 0.2 percent thymol, 10 percent formalin, and 0.2 percent sodium azide, during 3 periods of storage: 7 days, 30 days and 6 months, resulting in 9 groups (n = 10). The roots were cut off and the buccal surface was ground with #600-grit silicon carbide paper. The surface was conditioned with 37 percent phosphoric acid for 15 s and a composite resin restoration (TPH Spectrum) was fixed using a one-bottle adhesive system (Adper Single Bond) and a dual-cured resinous cement (Rely X ARC) under a load of 500 g for 5 minutes. The samples were serially cut perpendicular to the bonded interface to obtain slices of 1.2 mm in thickness. Each slab was trimmed with a cylindrical diamond bur resulting in an hourglass shape with a cross-sectional area of approximately 1 mm². The microtensile bond strength (μTBS) testing was performed in a testing machine (EMIC 2000 DL) at a 0.5 mm/minute crosshead-speed until failure. After fracture, the specimens were examined under SEM to analyze the mode of fracture. μTBS Means were expressed in MPa and the data were analyzed by two-way ANOVA (3X3) and the Tukey test (α = 0.05). The storage times of 7 and 30 days produced no significant difference irrespective of the solution type. The formalin and thymol solutions, however, did have a negative influence on bond strength when the teeth were stored for 6 months.

Biosorption of Cu2+ from aqueous solutions by pretreated Cladosporium sp.

In this paper, adsorption properties of a pretreated of Cladosporium sp. for Cu2 were studied. The fungi pretreated with some chemical reagents exhibited higher Cu2+ removal capacities than native biomass. The optimum chemical reagent was 0.2M NaOH. After 0.2M NaOH pretreatment, optimum conditions of biosorption were found to be pH 5.0, temperature 35 degrees C, and stirring speed of 100rpm. Equilibrium isotherms were obtained from adsorption experiments and the biosorption maximun capacity obtained was at 28.31mg/g. The biosorbed metal ions were effectively eluted by 0.05M HNO3 solution. After eluting, the biosorbed metal ions biomass was regenerated by washing with deionized water and then contacted with a solution containing 0. 1M of Ca2+, Mg2+ ions before further adsorption tests. The pretreated fungi biomass could be used for three cycles: biosorption, elution of biosorbed ion, regeneration of biomass.

Sensitometric comparisons of Insight and Ektaspeed Plus films: effects of chemical developer depletion

O objetivo do presente estudo foi comparar as propriedades sensitométricas dos filmes Insight e Ektaspeed Plus processados manual e automaticamente em soluções novas e degradadas. Foram expostas 10 séries de cada tipo de filme (1 série = 5 filmes), sendo 5 séries processadas manualmente e 5, automaticamente. As primeiras duas séries de cada filme foram processadas em líquidos novos (uma série para cada tipo de processamento) e as demais foram processadas nas mesmas soluções progressivamente degradadas, uma vez por semana, até a conclusão do experimento dentro de 4 semanas. Curvas características foram construídas a fim de se comparar as propriedades sensitométricas dos filmes: contraste, latitude e sensibilidade. A degradação das soluções apresentou comportamentos distintos entre os tipos de processamento, o que pôde ser visto pelo padrão das curvas características que apresentaram modificações em sua forma, na terceira semana no processamento automático e na quarta semana no processamento manual. O filme Ektaspeed Plus apresentou uma redução de 11% nos seus valores de contraste no processamento manual e 53% no automático, já o Insight, 25% e 59%, respectivamente. O filme Insight, no entanto, apresentou uma menor perda de sensibilidade e um menor aumento de latitude. Concluiu-se que a degradação é mais rápida no processamento automático do que no manual. Em soluções degradadas, ambos os filmes apresentaram aumento de latitude e redução de contraste e sensibilidade. O Insight foi mais resistente em relação à latitude e sensibilidade, mas quanto ao contraste, o Ektaspeed Plus se apresentou mais estável.

Eletrophysiological properties of L-type Ca2+ currents in isolated adult mouse ventricular myocytes

The Whole-cell configuration of the patch-clamp technique was used to analyze the electrophysiological characteristics of the L-type calcium current (Ica) in single ventricular myocytes from hearts of adult mice. In Tyrode solution, ICa activated at -30 mV peaked at 0mV, and reverted near +60 mV. At 0mV, the peak current density was -8.1 + 2.5 pA/pF (N = 14). In a Na+ - and K+ -free solution containing 12 muM tetrodotoxin, and 10 mM Ca2+ or Ba2+ as charge carrier, the current-voltage relationship and the voltage dependence of inactivation were shifted about 10 mV to more depolarized voltages. The maximum Ba2+ current was two-times greater than the maximum Ca2+ current. The voltage dependencies of steady-state activation and inactivation were determined within the range of -70 to +50 mV and fitted with Boltzmann relations. The Ca2+ current showed half-maximal activation at -9.94 + 3.86 mV (slope factor (k) = 5.9 + 0.68 mV) and half-maximal inactivation at -27.65 + 5.74 mV (k = 6.37 + 2.79 mV), while the Ba2+ current showed half-maximal activation at -0.35 + 2.43 mV (k = 6.0 + 0.84 mV) and half-maximal inactivation at -20.33 + 2.40 mV (k = 5.36 + 1.10 mV). The time course of recovery of Ba2+ current from inactivation could be described using a single exponential function with a time constant of 83.37 msec. The overlap of activation and inactivation curves suggests the existence of an L-type Ca2+ window current with a maximal amplitude near -20mV.

The crystalloid vs colloid controversy in the era os hypertonic/hyperoncotic resuscitations: is the debate over?

The crystalloid vs. colloid controversy has been further complicated by the inclusion of hypertonic levels of sodium chloride (HTS) in both types of regimens. In this paper the recent literature on the controversy is reviewed. Colloids raise the intravascular colloid osmotic pressure and increase the fluid retention in the vessels. Crystalloids however, distribute into the interstitial and intravascular spaces at a ratio of approximately 3 to 1. It is therefore necessary to infuse a large volume of crystalloids in order to complete resuscitation. The advantage of colloids over isotonic crystalloids focuses primarily on the incidence of pulmonary edema. In an analysis of clinical trials, however, colloids were not proven to be superior to crystalloids. The use of HTS decreases the amount of crystalloid required for resuscitation. Pulmonary and systemic vasodilation, an increase in cardiac output and stroke volume, decreased intracranial pressure and an enhanced immunologic response have been noted experimentally, and the clinical evidence seems to corroborate these findings. HTS with dextran (HSD) has been used in an attempt to combine the rapid cellular fluid shift of hypertonicity with the vascular fluid shift of colloids. The experimental evidence is compelling. Whereas HTS has proven itself to be a superior resuscitation regimen, HSD has not yet warranted in a clinical setting the optimism which its experimental studies seem to indicate.

Nutrición parenteral total en hiperemesis gravídica grave / Total parenteral nutrition in acute hyperemesis gravidarum

La hiperemesis gravídico (HG) grave es una condición poco frecuente asociado al embarazo sin embargo representa un alto riesgo materno-fetal. En estos casos la nutrición parenteral total (NPT) representa una efectiva forma de tratamiento. Se presentan 8 pacientes con HG grave tratados con NPT por vía venosa central. La edad media fue de 27,5 (rango 23 a 36 años), la edad gestacional fluctuó entre las 8-19 semanas (media 15 semanas), y el volumen diario vómito pretratamiento fue de 840 cc (rango 400-1600 cc). Cinco pacientes tenían alteración nutricional calórico-proteica o proteico-visceral con compromiso parcial de la función hepática. Se administró solución glucosada 20-30 por ciento, solución de aminoácidos 8,5 por ciento, emulsión lipídica (3 casos), vitaminas, electrólitos y oligoelementos. El período de NPT hasta la mejoría osciló entre 5-16 días (media=7 días) con un total de 77 días. Los resultados perinatales fueron 7 RN AEG y 1 aborto retenido. Se obtuvo mejoría clínica satisfactoria en todos los casos y no hubo complicaciones