Hepatic enzymes and immunoinflammatory response to Bio-C Temp bioceramic intracanal medication implanted into the subcutaneous tissue of rats.

Our purpose was to evaluate the biocompatibility and hepatotoxicity of a new bioceramic intracanal medicament, Bio-C Temp (BIO). The biological properties of BIO were compared with calcium hydroxide-based intracanal medicament (Calen; CAL), used as gold pattern. Polyethylene tubes filled with BIO or CAL, and empty tubes (control group, CG) were implanted into subcutaneous tissue of rats. After 7, 15, 30 and 60 days, the samples were embedded in paraffin for morphological, quantitative and immunohistochemistry analyses. At 7 and 60 days, blood samples were collected for analysis of serum glutamic-oxaloacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) levels. The data were submitted to two-way ANOVA and Tukey's test (p ≤ 0.05). No significant difference was detected in serum GOT and GPT levels among BIO, CAL and CG specimens. In all periods, BIO specimens exhibited lower number of inflammatory cells and immunoexpression of IL-6, a pro-inflammatory cytokine, than CAL specimens. The reduction of these parameters was accompanied by significant increase in the collagen content and in the immunoexpression of IL-10, a cytokine involved in the tissue repair, over time. Our findings indicate that Bio-C Temp is biocompatible and had no hepatotoxicity effect.

Pseudoboehmite as a drug delivery system for acyclovir.

Herpes simplex virus is among the most prevalent sexually transmitted infections. Acyclovir is a potent, selective inhibitor of herpes viruses and it is indicated for the treatment and management of recurrent cold sores on the lips and face, genital herpes, among other diseases. The problem of the oral bioavailability of acyclovir is limited because of the low permeability across the gastrointestinal membrane. The use of nanoparticles of pseudoboehmite as a drug delivery system in vitro assays is a promising approach to further the permeability of acyclovir release. Here we report the synthesis of high purity pseudoboehmite from aluminium nitrate and ammonium hydroxide containing nanoparticles, using the sol-gel method, as a drug delivery system to improve the systemic bioavailability of acyclovir. The presence of pseudoboehmite nanoparticles were verified by infrared spectroscopy, transmission electron microscopy, and X-ray diffraction techniques. In vivo tests were performed with Wistar rats to compare the release of acyclovir, with and without the addition of pseudoboehmite. The administration of acyclovir with the addition of pseudoboehmite increased the drug content by 4.6 times in the plasma of Wistar rats after 4 h administration. We determined that the toxicity of pseudoboehmite is low up to 10 mg/mL, in gel and the dried pseudoboehmite nanoparticles.

Antimicrobial alumina nanobiostructures of disulfide- and triazole-linked peptides: Synthesis, characterization, membrane interactions and biological activity.

Due to the its physical-chemical properties, alumina nanoparticles have potential applications in several areas, such as nanobiomaterials for medicinal or orthodontic implants, although the introduction of these devices poses a serious risk of microbial infection. One convenient strategy to circumvent this problem is to associate the nanomaterials to antimicrobial peptides with broad-spectrum of activities. In this study we present two novel synthesis approaches to obtain fibrous type alumina nanoparticles covalently bound to antimicrobial peptides. In the first strategy, thiol functionalized alumina nanoparticles were linked via disulfide bond formation to a cysteine residue of an analog of the peptide BP100 containing a four amino acid spacer (Cys-Ala-Ala-Ala). In the second strategy, alumina nanoparticles were functionalized with azide groups and then bound to alkyne-decorated analogs of the peptides BP100 and DD K through a triazole linkage obtained via a copper(I)-catalyzed cycloaddition reaction. The complete physical-chemical characterization of the intermediates and final materials is presented along with in vitro biological assays and membrane interaction studies, which confirmed the activity of the obtained nanobiostructures against both bacteria and fungi. To our knowledge, this is the first report of aluminum nanoparticles covalently bound to triazole-peptides and to a disulfide bound antimicrobial peptide with high potential for biotechnological applications.

Surface modification using the biomimetic method in alumina-zirconia porous ceramics obtained by the replica method.

The modification of biomaterials approved by the Food and Drug Administration could be an alternative to reduce the period of use in humans. Porous bioceramics are widely used as support structures for bone formation and repair. This composite has essential characteristics for an implant, including good mechanical properties, high chemical stability, biocompatibility and adequate aesthetic appearance. Here, three-dimensional porous scaffolds of Al2 O3 containing 5% by volume of ZrO2 were produced by the replica method. These scaffolds had their surfaces chemically treated with phosphoric acid and were coated with calcium phosphate using the biomimetic method simulated body fluid (SBF, 5×) for 14 days. The scaffolds, before and after biomimetic coating, were characterized mechanically, morphologically and structurally by axial compression tests, scanning electron microscopy, microtomography, apparent porosity, X-ray diffractometry, near-infrared spectroscopy, inductively coupled plasma optical emission spectroscopy, energy dispersive X-ray spectroscopy and reactivity. The in vitro cell viability and formation of mineralization nodules were used to identify the potential for bone regeneration. The produced scaffols after immersion in SBF were able to induce the nodules formation. These characteristics are advantaged by the formation of different phases of calcium phosphates on the material surface in a reduced incubation period. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2615-2624, 2018.

Comparative study of the cytotoxic and genotoxic effects of titanium oxide and aluminium oxide nanoparticles in Chinese hamster ovary (CHO-K1) cells.

The aim of this study was to analyze the cytotoxicity and genotoxicity of titanium oxide (TiO(2)) and aluminium oxide (Al(2)O(3)) nanoparticles (NPs) on Chinese hamster ovary (CHO-K1) cells using neutral red (NR), mitochondrial activity (by MTT assay), sister chromatid exchange (SCE), micronucleus (MN) formation, and cell cycle kinetics techniques. Results showed a dose-related cytotoxic effect evidenced after 24h by changes in lysosomal and mitochondrial dehydrogenase activity. Interestingly, transmission electronic microscopy (TEM) showed the formation of perinuclear vesicles in CHO-K1 cells after treatment with both NPs during 24h but no NP was detected in the nuclei. Genotoxic effects were shown by MN frequencies which significantly increased at 0.5 and 1 microg/mL TiO(2) and 0.5-10 microg/mL Al(2)O(3). SCE frequencies were higher for cells treated with 1-5 microg/mL TiO(2). The absence of metaphases evidenced cytotoxicity for higher concentrations of TiO(2). No SCE induction was achieved after treatment with 1-25 microg/mL Al(2)O(3). In conclusion, findings showed cytotoxic and genotoxic effects of TiO(2) and Al(2)O(3) NPs on CHO-K1 cells. Possible causes of controversial reports are discussed further on.

Influência do tratamento superficial na resistência à traçäo da colagem do Artglass / Influence of superficial treatment on the Art Glass shear bond strength

O objetivo deste foi avaliar a influência do jateamento com óxido de alumínio, do condicionamento com ácido fluorídrico e ácido fosfórico no tratamento superficial do polímero de vidro Artglass (HERAEUS, Kulzer - Germany), verificando o efeito da aplicaçäo de agentes ativadores de superfície na resistência a traçäo. Os autores concluíram que o maior valor de resistência de uniäo é obtido com jateamento com óxido de alumínio associado ao silano; a análise por M.E.V. da morfologia superficial demonstrou um padräo favorável ao embricamento micromecânico quando do jateamento com óxido de alumínio

Dental enamel: qualitative evaluation of the surface after application of aluminum oxide (microetching) using the scanning electron microscope / Esmalte dental: avaliaçäo qualitativa da superfície tratada com jato de óxido de alumínio (\"microetching\") por meio de microscopia eletrônica de varredura

A odontologia de nossos tempos conta com inúmeros recursos para o tratamento de pacientes. Com o desenvolvimento dos materiais adesivos e a introduçäo de novas técnicas restauradoras, a estrutura dental pode receber diferentes tipos de tratamentos superficiais. O uso do fluxo de óxido de alumínio em alta velocidade para a remoçäo de estrutura dental foi descrito por Black em 1945, no entanto, a literatura pertinente ao uso do jato de óxido de alumínio ainda permanece escassa no que se refere às alteraçöes produzidas na estrutura dental. Atualmente, com o desenvolvimento de novos equipamentos de ar abrasivo, o procedimento de microabrasäo vem sendo incorporado a várias técnicas restauradoras adesivas no preparo de superfícies dentais e superfícies internas de restauraçöes indiretas, as quais receberäo a aplicaçäo de materiais adesivos. O objetivo simples deste estudo foi avaliar as alteraçöes produzidas pelo uso do ar abrasivo sobre o esmalte dental por meio de microscopia eletrônica de varredura, observando-se as alteraçöes micromorfológicas superficiais. A importância deste estudo baseia-se no fato de que tratamentos superficiais alternativos químicos e mecânicos venham a ser introduzidos para o condicionamento de superficies, inclusive do esmalte dental