RESUMO
In this study, two new nanohybrids (NH-A and NH-B) were synthesized through carbodiimide-assisted coupling. The reaction was performed between carboxymethyl-scleroglucans (CMS-A and CMS-B) with different degrees of substitution and commercial amino-functionalized silica nanoparticles using 4-(dimethylamino)-pyridine (DMAP) and N,N'-dicyclohexylcarbodiimide (DCC) as catalysts. The morphology and properties of the nanohybrids were investigated by using transmission (TEM) and scanning electron microscopy (SEM), electron-dispersive scanning (EDS), attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FT-IR), X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (XRD), inductively coupled plasma atomic emission spectroscopy (ICP-OES), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic light scattering (DLS). The nanohybrids exhibited differences in structure due to the incorporation of polyhedral oligomeric silsesquioxane (POSS) materials. The results reveal that hybrid nanomaterials exhibit similar thermal properties but differ in morphology, chemical structure, and crystallinity properties. Finally, a viscosity study was performed on the newly obtained nanohybrid materials; viscosities of nanohybrids increased significantly in comparison to the carboxymethyl-scleroglucans, with a viscosity difference of 7.2% for NH-A and up to 32.6% for NH-B.
RESUMO
The objective of this study is to evaluate the effect of 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) and chitosan (CHI) on the adhesive interface of resin cements to root dentine. Forty-five upper canines were sectioned, endodontically treated, prepared and divided into three groups according to dentine treatment (distilled water-DW, CHI 0.2% and EDC 0.5) and in three subgroups according to resin cement: RelyX ARC, Panavia F 2.0 or RelyX U200. Slices were obtained, with five slices of each third submitted to the analysis of the adaptation of the adhesive interface through scores and the perimeter with gaps in confocal laser scanning microscopy and one slice of each third later evaluated qualitatively in scanning electron microscopy. The results were analyzed using with Kruskal-Wallis and Spearman correlation tests. There was no difference in adaptation for the different resin cements (p = .438). EDC presented better adaptation when compared to the groups treated with DW and CHI (p < .001), while the CHI and DW presented similar adaptation values (p = .365). No difference was observed in the perimeter referring to the gap areas for the different resin cements (p = .510). EDC showed a lower percentage of perimeters with gaps when compared to CHI (p < .001), with the percentage of perimeter with gaps of teeth treated with CHI being lower than DW (p < .001). A positive correlation coefficient equal to 0.763 was obtained between the perimeter with gaps and the adaptation data of the adhesive interface (p < .001). EDC resulted in better adaptation of the adhesive interface and a lower percentage of perimeters with gaps compared to chitosan.
Assuntos
Quitosana , Colagem Dentária , Técnica para Retentor Intrarradicular , Cimentos de Resina , Cimentação/métodos , Carbodi-Imidas , Dentina , Teste de MateriaisRESUMO
Abstract The aim of this study was to evaluate the effect of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) on bond strength of fiberglass posts in root canals obturated with different endodontic sealers. Seventy-eight mandibular premolars were obturated with three sealers (n=26): Endofill (END), AH Plus (AHP), and Endosequence BC Sealer (EBS). After preparation of the post space, two subgroups were formed according to the cementation of the posts (n=13): with EDC (EDC), and without EDC (control - CON). The specimens were submitted to a pull-out test, failure mode classification, and root canal surface evaluation by scanning electron microscopy after post displacement. Regarding the bond strength, a significant difference between the EDC and CON subgroups occurred only in the END (p=0.001). No difference was detected among the CON subgroups (p=0.339). However, among the EDC subgroups, AHP presented significantly higher values (END versus AHP: p=0.001; AHP versus EBS: p=0.016). Upon classification of failure modes, score 1 (≥ 50% of cement) was the most commonly observed, except for the END + EDC. Remains of endodontic sealers and resin cements were found in the cervical third, but without statistical difference (p=0.269), while in the middle third, difference occurred (p=0.004). In conclusion, EDC decreases bond strength when associated with END sealer, without changing the failure mode between the resin cement and fiberglass post. The best performance was observed when EDC was combined with AHP sealer.
Resumo O objetivo deste estudo foi avaliar o efeito da 1-etil-3- (3-dimetilaminopropil) carbodiimida (EDC) na resistência de união de pinos de fibra de vidro em canais radiculares obturados com diferentes cimentos endodônticos. Setenta e oito pré-molares inferiores foram obturados com três cimentos endodônticos (n=26): Endofill (END), AH Plus (AHP) e Endosequence BC Sealer (EBS). Após o preparo do espaço para pino, dois subgrupos formaram-se conforme a cimentação dos pinos (n=13): com EDC e sem EDC (controle - CON). Os espécimes foram submetidos ao teste pull-out, classificação do modo de falha e avaliação da superfície do canal radicular por microscopia eletrônica de varredura após o deslocamento. Quanto à força de resistência de união, uma diferença estatisticamente significativa ocorreu entre os subgrupos EDC e CON apenas no END (p=0,001). Não foi detectada diferença entre os subgrupos CON (p=0,339). Contudo, no subgrupo EDC, o AHP apresentou maiores valores (END versus AHP: p=0,001; AHP versus EBS: p=0,016). Acerca da classificação dos modos de falha, o escore 1 (≥50% de cimento) foi o mais comumente observado, exceto para END + EDC. Restos de cimentos endodônticos e cimentos resinosos foram encontrados no terço cervical, mas sem diferença estatística (p=0,269), enquanto no terço médio, houve diferença (p=0,004). Em conclusão, o EDC diminui a resistência de união quando associado ao cimento END, sem alterar o modo de falha entre o cimento resinoso e o pino de fibra de vidro. O melhor desempenho foi observado quanto o EDC foi usado com o cimento AHP.
Assuntos
Técnica para Retentor Intrarradicular , Colagem Dentária , Carbodi-Imidas , Cimentação , Cimentos de ResinaRESUMO
AIM: To evaluate the effect of carbodiimide (EDC) and chlorhexidine (CHX) on the bond strength (BS) of resin cement to root dentine of teeth submitted to radiotherapy. METHODOLOGY: One hundred and twenty extracted maxillary canines were selected and assigned to 2 groups (n = 60): nonirradiated and irradiated (30 cycles of 2 Gy, total 60 Gy). Roots lengths were standardized, and canals were prepared and filled. Post spaces were then prepared, and the samples were redistributed according to dentine treatment (n = 20): saline solution (SF); CHX 2%; or EDC 0.5M. After drying the post space, fibreglass posts were cemented. Cross-sectioned slices were obtained, and in half of the specimens of each subgroup (n = 10), the analysis was performed immediately; the others (n = 10) were stored for 10 months before analyses. The most cervical slice of each third was subjected to a push-out test and failure pattern analysis (n = 10), and the most apical slice submitted to the analysis of the adhesive interface by SEM (n = 5). The bond strength data were submitted to anova and Tukey tests, the adhesive interface adaptation was submitted to Kruskal-Wallis and Dunn's tests, and the Chi-square test was used to evaluate the type of failure. RESULTS: The irradiated specimens had significantly lower bond strength (13.8 ± 4.3) than the nonirradiated (18.1 ± 3.1; P < 0.001). For the irradiated teeth, the bond strengths were significantly lower in the SF and CHX groups (P < 0.001). Also, the bond strengths reduced significantly after 10 months in the SF and CHX groups (P < 0.001). Cohesive failures occurred in dentine for irradiated specimens. Poorer interface adaptation, dentine fractures and microfractures were observed in irradiated specimens, and better adaptation was observed for specimens after EDC treatment. CONCLUSIONS: Radiotherapy was associated with lower bond strength and worse interface adaptation. Dentine treatment with EDC contributed to adhesive interface longevity during the cementation of glass fibre posts in nonirradiated and irradiated teeth.
Assuntos
Colagem Dentária , Técnica para Retentor Intrarradicular , Carbodi-Imidas , Clorexidina , Cavidade Pulpar , Análise do Estresse Dentário , Dentina , Vidro , Teste de Materiais , Cimentos de ResinaRESUMO
Sodium alginate (Alg) reacted with antibiotic gentamicin sulfate (GS) in an aqueous-phase condition mediated by carbodiimide chemistry, in the molar ratios Alg: GS of (1:0.5), (1:1) and (1:2). The Alg-GS conjugated derivatives were characterized by elemental analysis for nitrogen content, Fourier transform infrared spectroscopy in the attenuated total reflection mode (FTIR-ATR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), thermogravimetric analyses (TGA) and water sorption measurements. XPS and FTIR-ATR analyses clearly indicated that GS molecules covalently attached to the backbone of the alginate chains by amide bond formation. The highest amount of GS bound to Alg (43.5⯱â¯0.4â¯wt%) and the highest swelling ratio (4962⯱â¯661%) were observed for the Alg-GS (1:2) sample. Bioluminescence assays with Pseudomonas aeruginosa PAO1/lecA:lux and colony forming counting of Staphylococcus aureus and Escherichia coli upon contact with all Alg-GS conjugates revealed microbicidal activity; however, Alg-GS (1:2) was the most efficient, due to the highest GS content.
Assuntos
Alginatos/química , Anti-Infecciosos/química , Gentamicinas/química , Hidrogéis/química , Carbodi-Imidas/química , Quitosana/química , Ácido Glucurônico/química , Ácidos Hexurônicos/química , Pseudomonas aeruginosa/efeitos dos fármacos , Espectroscopia de Infravermelho com Transformada de Fourier , Staphylococcus aureus/efeitos dos fármacos , TermogravimetriaRESUMO
Eicosanoids are bioactive lipids derived from enzymatic metabolism of arachidonic acid via the cyclooxygenase (COX) and lipoxygenase (LOX) pathways. These lipids are newly formed and nonstorable molecules that have important roles in physiological and pathological processes. The particular interest to determine intracellular compartmentalization of eicosanoid-synthetic machinery has emerged as a key component in the regulation of eicosanoid synthesis and in delineating functional intracellular and extracellular actions of eicosanoids. In this chapter, we discuss the EicosaCell protocol, an assay that enables the intracellular detection and localization of eicosanoid lipid mediator-synthesizing compartments by means of a strategy to covalently cross-link and immobilize eicosanoids at their sites of synthesis followed by immunofluorescent-based localization of the targeted eicosanoid. EicosaCell assays have been successfully used to identify different intracellular compartments of synthesis of prostaglandins and leukotrienes upon cellular activation. This chapter covers basics of EicosaCell assay including its selection of reagents, immunodetection design as well as some troubleshooting recommendations.
Assuntos
Bioensaio/métodos , Eicosanoides/biossíntese , Animais , Imunofluorescência , Processamento de Imagem Assistida por Computador/métodos , Espaço Intracelular/metabolismo , Metabolismo dos Lipídeos , Camundongos , Microscopia de Fluorescência , Imagem Molecular/métodos , Imagem Óptica , Fagossomos , Software , Coloração e Rotulagem/métodosRESUMO
Tem sido demonstrado que a carbodiimida (EDC) apresenta notável potencial inibidor de proteases (MMPs) e de melhorar as propriedades mecânicas do colágeno quando aplicada sobre a dentina desmineralizada. Entretanto, não existem informações a respeito de sua ação antimicrobiana sobre microrganismos comumente encontrados em lesões de cárie ou mesmo após a sua remoção. Objetivo: Investigar a atividade antimicrobiana do EDC em diferentes concentrações sobre microrganismos presentes em cavidades cariosas. Métodos: Soluções de EDC foram preparadas e testadas contra S. mutans e sobrinus, L. acidophilus e Candida albicans. Inicialmente, foi utilizado o teste de difusão em ágar, no qual discos de papel filtro foram impregnados com EDC 2, 1, 0,5, 0,3 ou 0,1 mol/L, clorexidina 0,12%, nistatina 1% ou tampão Sorensen pH 6,2 (n=6). Em seguida, foi determinada a concentração inibitória mínima (CIM) e bactericida mínima (CBM) do EDC sobre L. acidophilus em suspensão planctônica (n=9), por meio de turvamento. Por fim, a atividade do EDC (de 0,01 à 2 mol/L) sobre L. acidophilus em biofilme monoespécie foi definida por meio do ensaio de XTT (n=6). Os dados foram submetidos aos testes estatísticos de ANOVA e Tukey ou Mann-Whitney (p<0,05). Resultados: No teste de difusão em ágar, nenhuma atividade antimicrobiana foi observada para EDC nas concentrações de 0,1 e 0,3 mol/L, assim como para o grupo controle. EDC 0,5, 1 e 2 mol/L exerceu efeito antimicrobiano apenas sobre L. acidophilus. A CIM do EDC foi de 0,01 mol/L e a CBM foi de 0,03 mol/L. Todas as concentrações de EDC igual ou superiores a 0,05 mol/L foram capazes de reduzir significantemente o metabolismo do biofilme formado por L. acidophilus. Essa redução variou de 84,2 para 0,05 mol/L até 93,4% para 2 mol/L. Conclusão: O EDC apresentou atividade antimicrobiana apenas contra L. acidophilus reduzindo significantemente o crescimento deste microrganismo quando em suspensão planctônica e o seu metabolismo quando em biofilme monoespécie a partir de 0,05 mol/L
It has been demonstrated that carbodiimide (EDC) is a potent protease inhibitor (MMPs) and is able to improve the mechanical properties of collagen when applied on the demineralized dentin. However, there is no information about its antimicrobial effect on microorganisms commonly found in caries lesions or even after its removal. Objective: To investigate the antimicrobial activity of different concentrations of EDC against microorganisms present in caries lesions. Methods: EDC solutions were prepared and tested against S. mutans and sobrinus, L. acidophilus and Candida albicans. Initially, the agar diffusion test was used, where paper discs were impregnated with 2, 1, 0.5, 0.3 or 0.1 mol/L EDC, 0.12% chlorhexidine, nistatin 1% or Sorensen's buffer pH 6.2 (control) (n=6). Then, the minimum inhibitory (MIC) and bactericide concentrations (MBC) of EDC were determined against L. acidophilus using turbidity. Finally, the growth inhibitory activity of EDC (from 0.01 to 2 mol/L) against L. acidophilus in monoespecies biofilm was defined using the XTT assay (n=6). Data were submitted to ANOVA and Tukey tests or Mann-Whitney (p<0.05). Results: For the agar diffusion test, lack of antimicrobial activity was seen for EDC at 0.1 and 0.3 mol/L, as well as for the control group. 0.5, 1 and 2 mol/L EDC exerted a growth inhibitory effect only against L. acidophilus. The MIC for EDC was set as 0.01 mol/L and the MBC as 0.03 mol/L. Concentrations equal to or greater than 0.05 mol/L were capable of significantly reducing the metabolism of L. acidophilus when in monospecies biofilm. This reduction ranged from 84.2% for 0.05 mol/L to 93.4% for 2 mol/L. Conclusion: EDC exerted antibacterial activity only against L. acidophilus significantly reducing its growth in planktonic suspension and its metabolism in biofilms in the concentration of 0.05 mol/L or higher