ABSTRACT Among titanium alloys with non-toxic elements, the Ti-25Nb-25Ta alloy has good elastic behavior for applications in osseous implants, biocompatibility, and excellent corrosion resistance. The present study aimed to better the biocompatibility characteristics of Ti-25Nb-25Ta alloy modifying its surface through Plasma Electrolytic Oxidation (PEO) treatment. The formed oxide coating is amorphous and composed of two distinct porous formations: smaller hole-shaped pores and larger volcano-like pores. The regions with the formation of smaller pores and in the hole shaped presented the highest atomic percentage of the chemical element phosphorus. Nanoindentation tests have shown that the hardness of the Ti-25Nb-25Ta alloy is slightly lower than the commercially pure grade 2 titanium (a material used as reference), while elastic modulus measurements of Ti-25Nb-25Ta presented more suitable values for implant application (lower values when compared with titanium reference). After PEO treatment there were significant mechanical surface improvements (increased fairly surface hardness and decreased elastic modulus) for application in osseous tissue. Despite the Ti-25Nb-25Ta alloy presented excellent characteristics for applications in hard biological tissues, the PEO treatment better its features.

RESUMO As estratégias atuais no design de biomateriais incluem a alteração das propriedades da superfície do biomaterial para direcionar sistematicamente o comportamento celular. O titânio é o material mais prevalente para uso em implantes devido às suas propriedades mecânicas. Modificações na superfície de titânio podem otimizar a osseointegração de um implante modulando a resposta imunossupressora, acelerando o processo de cicatrização e reduzindo o tempo de tratamento. O crescimento de nanotubos de TiO2 através da anodização pode alterar as propriedades da superfície do titânio comercialmente puro, permitindo uma melhor resposta quando inserido no corpo humano. Objetivo do presente trabalho foi o crescimento de nanotubos de TiO2 na superfície de discos de titânio comercialmente puro e a redução do tempo de anodização, com agitação durante a oxidação anódica, tensão de 30V e eletrólito composto por 90-10% (v/v) de etilenoglicol-H2O e 1% NH4F (m/m). Para determinar a melhor intensidade de agitação foi estabelecido um tempo de 20 minutos. A classificação da intensidade da agitação foi feita pelo método de observação, classificada como fraca, moderada e vigorosa. Para determinar o melhor tempo de oxidação anódica, foi estabelecida intensidade de agitação moderada. O tempo de anodização deve permitir que a estrutura se reorganize e aumente o grau de auto-organização, assim, foram estabelecidos tempos de 20, 30 e 40 minutos. Em seguida, as amostras foram submetidas à calcinação em forno mufla EDG com taxa de aquecimento de 5ºC/minuto, mantida por 1 hora a 450ºC. A morfologia da superfície foi analisada por microscopia eletrônica de varredura (MEV), ângulo de contato e difração de raios X (DRX).

ABSTRACT Current strategies in the design of biomaterials include altering the surface properties of the biomaterial to systematically direct cellular behavior. Titanium is the most prevalent material for use in implants due to its mechanical properties. Modifications to the titanium surface can optimize the osseointegration of an implant by modulating the immunosuppressive response, accelerating the healing process and reducing treatment time. The growth of TiO2 nanotubes through anodization can alter the surface properties of commercially pure titanium, allowing a better response when inserted into the human body. Objective of the present work was the growth of TiO2 nanotubes on the surface of commercially pure titanium discs and the reduction of anodization time, with agitation during anodic oxidation, voltage of 30V and electrolyte composed of 90-10% (v/v) ethyleneglycol-H2O and 1% NH4F (w/w). To determine the best agitation intensity, a time of 20 minutes was established. The agitation intensity was classified by the observation method, classified as weak, moderate and vigorous. To determine the best anodic oxidation time, moderate agitation intensity was established. The anodizing time should allow the structure to reorganize and increase the degree of self-organization, thus, times of 20, 30 and 40 minutes have been established. Then, the samples were subjected to calcination in an EDG muffle furnace with a heating rate of 5ºC/minute, maintained for 1 hour at 450ºC. The surface morphology was analyzed by scanning electron microscopy (SEM), contact angle and X-ray diffraction (XRD).

Resumo Introdução Adultos com sequelas de doenças periodontais tendem a apresentar perda óssea, com consequente vestibularização dos incisivos superiores. Objetivo A influência da perda óssea e da inclinação do incisivo superior na distribuição de tensões devido a forças mastigatórias simuladas foram avaliadas nesse estudo. Material e método Modelos em resina epóxi foram confeccionados em três condições (sem perda óssea e com perda óssea de 5mm e 8mm). Aumentos na inclinação vestibular do incisivo superior de 10° e 20° foram obtidos com um bloco metálico chanfrado. Cargas de 100N foram aplicadas cinco vezes em cada condição usando uma máquina de ensaio universal. Os modelos foram observados e filmados com um polariscópio circular. Ordens de franjas isocromáticas (tensões) nas faces vestibular, lingual e apical foram registradas. A concordância dos dados foi avaliada pelo teste kappa ponderado e os resultados foram 0,89 e 0,82 para intra e interexaminadores, respectivamente. Resultado Os resultados dos testes de Kruskal-Wallis e SNK indicaram maiores tensões (2,0) com aumento da inclinação vestibular na face vestibular; maiores tensões (2,67) com aumento da perda óssea; maior tensão com a associação de perda óssea e inclinação vestibular (3,6); e as maiores tensões tenderam a concentrar-se na face vestibular, exceto em casos de inclinação normal e sem perda óssea (0,45). Conclusão Concluiu-se que aumentos tanto da inclinação vestibular dos incisivos superiores quanto da perda óssea aumentam as tensões perirradiculares, e a combinação desses fatores aumenta ainda mais as tensões devido às forças mastigatórias, com a maior concentração na face vestibular.

Abstract Introduction Adults with sequelae of periodontal disease tend to have bone loss, with consequent flaring of the maxillary incisors. Objective The influence of bone loss and the inclination of the maxillary incisor in the distribution of stresses due to simulated bite forces was studied. Material and method Models in epoxy resin were made in three conditions (without bone loss and with bone loss of 5mm and 8mm). Increases in the labial inclination of the maxillary incisor of 10° and 20° were obtained with a beveled metallic block. Loads of 100N were applied five times in each condition using a universal test machine. The models were observed and filmed with a circular polariscope. Orders of isochromatic fringes (stresses) on the labial, lingual, and apex surfaces were recorded. The agreement of the data was evaluated using the weighted kappa test, and the results were 0.89 and 0.82 for intra- and inter-examiners, respectively. Result The results of the Kruskal–Wallis and SNK tests indicated higher stresses (2.0) with increased labial inclination in the labial surface; higher stresses (2.67) with increased bone loss; higher greater stresses with the association of bone loss and labial-inclination (3.6); and the highest stresses tended to concentrate on the labial surfaces, except in cases of normal inclination and without bone loss (0.45). Conclusion It was concluded that increases in both the labial inclination of the maxillary incisors and bone loss increase periradicular stresses, and the combination of these factors further increases the stresses due to bite forces, with the highest concentration on the labial side.

The purpose of this study is the surface modification of Ti10Mo8Nb experimental alloy by using TiO2 nanostructure growth. Ingots of the Ti10Mo8Nb experimental alloy were produced by fusion from sheets of molybdenum, niobium, and titanium commercially pure in an arc melting furnace under argon atmosphere. The potentiostatic anodic oxidation was performed using an electrolyte formed of glycerol and H2O (1: 1 by vol.) with the addition of 2.7% (w/v) NH4F under 20 V for 3 h at room temperature. After the surface treatment, the samples were annealing. The surface of the alloy was analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), contact angle, surface energy measurements. In vitro studies, such as cell and bacterial adhesion, were performed to evaluate the response of this treatment. The Ti10Mo8Nb alloy exhibited beta phase after the processing. After the surface treatment, a nanoporous layer of TiO was obtained. The anatase phase was found in the annealed samples (450 ºC for 3 hours). In vitro analyzes showed cell growth viability and decreased bacterial proliferation due to the larger specific surface area.

Titanium (Ti) and its alloys are widely used for medical and dental fields due to their excellent biocompatibility, high corrosion resistance, high specific strength and excellent mechanical properties. Different methods have been developed to improve the surface properties of titanium-based implant materials, and consequently the bone-bonding ability. The Ti-7.5Mo alloy was activated by an alkaline treatment with 5M NaOH, heat treatment and subsequent immersion in SBFx5 to investigate the in vitro response of osteoblastic-like cells MG-G3 on altered biomimetic surfaces. Sample surfaces were characterized by scanning electron microscopy. Cytotoxicity was assessed by the MTT assay, total protein content, alkaline phosphatase activity (ALP) and mineralized bone-like nodule formation. It was shown the que alkali treatment led to the formation of sodium titanate and immersion in SBFx5 formed a film of calcium phosphate. The alkaline treatment and heat treatment of 7.5 Ti-Mo alloys followed by soaking them in SBFx5 for 24 hours is a suitable technique once the final samples were biocompatible, allowed the attachment of the osteoblastic-like cells (MG-G3), and increased the mineralized like-bone nodules formation by these cells.

In this study the corrosion resistance of Ti30Ta experimental alloy was evaluated when submitted to different deformation rates. Alloys were processed in arc melting, furnace, forged and treated. The samples were machined in accordance with ASTME9-09 standard to carry out compression tests. The influence of deformation was evaluated by optical microscopy and XRD, and Eletrochemical parameters were analyzed in the most severe condition of deformation (22%). Corrosion resistance exhibited the same behavior for two conditions, 22% and without deformation.

In this study, the effects of the parameters such as applied potential difference, time and annealing temperature in the titania nanotubes formation were evaluated. The morphology of the nanotubes was evaluted by using Field Emission Gun - Scanning Electron Microscope (FEG-SEM), Atomic Force Microscope (AFM), contact angle and X-rays diffraction (XRD). Self-organized nano-structures were formed on the Ti-7.5Mo alloy surface from the same electrolyte (glycerol/NH4F) for all conditions. It was observed that the potential influenced the diameter while the length was changed according to the anodization time lenght. The presence of the phases anatase and rutile was altered by annealing temperature. Results showed that 20V-48h-450 ºC was the better than other conditions for application as biomaterial.

RESUMO Introdução: a deposição de filme de polímero a plasma foi criada para modificar as propriedades de superfície dos braquetes ortodônticos metálicos, com o intuito de inibir a adesão bacteriana. Métodos: filmes finos de polímero de hexametildisiloxano (HMDSO) foram depositados em braquetes ortodônticos de aço inoxidável convencionais (n = 10) e autoligáveis (n = 10), utilizando a técnica de radiofrequência PECVD (Plasma-Enhanced Chemical Vapor Deposition). As amostras foram divididas em dois grupos, de acordo com o tipo de braquete, e dois subgrupos após o tratamento de superfície. A microscopia eletrônica de varredura (MEV) foi realizada para avaliar a presença de adesão bacteriana sobre as superfícies das amostras (região de ranhura horizontal e aletas) e a integridade da camada de filme. A Interferometria Confocal (CI) avaliou a rugosidade, e a molhabilidade superficial foi avaliada por goniometria. Para análise de adesão bacteriana, as amostras foram expostas durante 72 horas a uma solução de Streptococcus mutans, para formação de biofilme. Os valores obtidos para a rugosidade da superfície foram analisados pelo teste de Mann-Whitney, enquanto a adesão do biofilme foi avaliada pelos testes de Kruskal-Wallis e SNK. Resultados: observaram-se diferenças estatisticamente significativas (p <0,05) para a rugosidade superficial e redução da adesão bacteriana em braquetes convencionais após o tratamento da superfície, e entre braquetes convencionais e autoligáveis. Não foram observadas diferenças estatísticas significativas entre os grupos autoligáveis (p> 0,05). Conclusão: a deposição de polímero a plasma só foi efetiva na redução da rugosidade superficial e adesão bacteriana em braquetes convencionais. Observou-se, também, que os braquetes convencionais apresentaram menor adesão ao biofilme do que os braquetes autoligáveis, apesar da ausência de filme.

ABSTRACT Introduction: Plasma-polymerized film deposition was created to modify metallic orthodontic brackets surface properties in order to inhibit bacterial adhesion. Methods: Hexamethyldisiloxane (HMDSO) polymer films were deposited on conventional (n = 10) and self-ligating (n = 10) stainless steel orthodontic brackets using the Plasma-Enhanced Chemical Vapor Deposition (PECVD) radio frequency technique. The samples were divided into two groups according to the kind of bracket and two subgroups after surface treatment. Scanning Electron Microscopy (SEM) analysis was performed to assess the presence of bacterial adhesion over samples surfaces (slot and wings region) and film layer integrity. Surface roughness was assessed by Confocal Interferometry (CI) and surface wettability, by goniometry. For bacterial adhesion analysis, samples were exposed for 72 hours to a Streptococcus mutans solution for biofilm formation. The values obtained for surface roughness were analyzed using the Mann-Whitney test while biofilm adhesion were assessed by Kruskal-Wallis and SNK test. Results: Significant statistical differences (p< 0.05) for surface roughness and bacterial adhesion reduction were observed on conventional brackets after surface treatment and between conventional and self-ligating brackets; no significant statistical differences were observed between self-ligating groups (p> 0.05). Conclusion: Plasma-polymerized film deposition was only effective on reducing surface roughness and bacterial adhesion in conventional brackets. It was also noted that conventional brackets showed lower biofilm adhesion than self-ligating brackets despite the absence of film.

Titanium and its alloys have been used in dentistry to due their excellent corrosion resistance and biocompatibility. However, titanium coating is bioinert material and it cannot chemically bond to bone tissue. The purpose of this work was evaluating the bioactivity of Ti-7,5Mo alloy after chemical treatment using H2SO4 / H2O2 and soaking in SBF. Samples were chemically treated at room temperature for 4 h with a solution consisting of equal volumes of concentrated H2SO4 (200 ml) and 30% aqueous solution H2O2 (200 ml). The oxidized samples were rinsed with distilled water and were heat treated at 600°C for 1h in a electrical furnace in air. Then, all samples were immersed in SBF (Simulated Body Fluid) for 7 and 14 days to form a calcium phosphate (Ca/P) coating on the surface. Surfaces were characterized by using SEM, AFM and contact angle. The results indicated that calcium phosphate (Ca/P) was formed on surface of Ti-7.5Mo experimental alloy.

Titanium alloys are widely used in the manufacture of biomedical implants because they possess an excellent combination of physical properties and outstanding biocompatibility. Today, the most widely used alloy is Ti-6Al-4V, but some studies have reported adverse effects with the long-term presence of Al and V in the body, without mentioning that the elasticity modulus value of this alloy is far superior to the bone. Thus, there is a need to develop new Ti-based alloys without Al and V that have a lower modulus, greater biocompatibility, and similar mechanical strength. In this paper, we investigated the effect of Nb as a substitutional solute on the mechanical properties of Ti-Nb alloys, prepared in an arc-melting furnace and characterized by density, X-ray diffraction, optical microscopy, hardness and elasticity modulus measurements. The X-ray and microscopy measurements show a predominance of the α phase. The microhardness values showed a tendency to increase with the concentration of niobium in the alloy. Regarding the elasticity modulus, it was observed a nonlinear behavior with respect to the concentration of niobium. This behavior is associated with the presence of the α phase.

With the increase in life expectancy, biomaterials have become an increasingly important focus of research because they are used to replace parts and functions of the human body, thus contributing to improved quality of life. In the development of new biomaterials, the Ti-15Mo alloy is particularly significant. In this study, the Ti-15Mo alloy was produced using an arc-melting furnace and then characterized by density, X-ray diffraction, optical microscopy, hardness and dynamic elasticity modulus measurements, and cytotoxicity tests. The microstructure was obtained with β predominance. Microhardness, elasticity modulus, and cytotoxicity testing results showed that this material has great potential for use as biomaterial, mainly in orthopedic applications.