Search

A titanium surface nitrided by plasma contains nitrogen ions that guarantee resistance to corrosion and biocompatibility. Despite this, no descriptions concerning the influence of the expression of cell adhesion proteins and their influence on osteogenic cell differentiation are available. Thus, the present study aimed to assess the response of murine pre‐osteoblastic cells (MC3T3‐E1) cultured on nitrided titanium surfaces. Pre‐osteoblastic cells were grown on polished titanium discs, used as controls, and on previously characterized plasma‐nitrided titanium discs. Cells from both groups were submitted to the MTT cell viability test. The expressions of α5, α2, and β1 integrin were assessed by flow cytometry and immunofluorescence, while osteocalcin expression was assessed by flow cytometry. The nitrided surface presented higher α2 and β1 integrin expressions, as well as osteocalcin expression, when compared to the polished surface, with no alterations in cell viability. These findings seem to suggest that the plasma nitriding treatment produces a titanium surface with the potential for effective in vitro osseointegration.

Biomedical devices introduced in the human body interact initially with blood cells, their success being dependent on the result of this interaction. This work aimed to obtain optimum biocompatibility and hemocompatibility of the titanium by plasma treatment. For this, discs of commercially pure titanium (CP) were subjected to plasma nitriding using different mixture of nitrogen and hydrogen; the effect of addition of hydrogen to the nitriding plasma was investigated. Before and after treatment, samples were evaluated in terms of topography and wettability using atomic force microscopy and sessile drop tests, respectively. The titanium biological response was evaluated in vitro through the application of platelet-rich plasma (PRP) on the surfaces modified and analysis of their behaviour from the point of view of surface tension and cell adhesion. Surface properties, such as roughness and wettability, were sensitive to the hydrogen/nitrogen ratio in the nitriding plasma, suggesting a strategy for producing different surfaces of biomedical devices. Results showed to be possible to obtain surfaces with different response to the adhesion of platelets, covering different applications.

We evaluated the effects of titanium plasma nitriding and oxidation on live endothelial cell viscoelasticity. For this, mechanically polished titanium surfaces and two surfaces treated by planar cathode discharge in nitriding (36N2 and 24H2) and oxidant (36O2 and 24H2). Surfaces were characterized regarding wettability, roughness and chemical composition. Rabbit aortic endothelial cells (RAECs) were cultured on the titanium surfaces. Cell morphology, viability and viscoelasticity were evaluated by scanning electron microscopy (SEM), methyl thiazolyl tetrazolium (MTT) assay and atomic force microscopy (AFM), respectively. Grazing Incidence X-ray Diffraction confirmed the presence of TiN0,26 on the surface (grazing angle theta 1°) of the nitrided samples, decreasing with depth. On the oxidized surface had the formation of TiO3 on the material surface (Theta 1°) and in the deeper layers was noted, with a marked presence of Ti (Theta 3°). Both plasma treatments increased surface roughness and they are hydrophilic (angle < 90°). However, oxidation led to a more hydrophilic titanium surface (66.59° ± 3.65 vs. 76.88° ± 2.68; p = 0.001) due to titanium oxide films in their stoichiometric varieties (Ti3O, TiO2, Ti6O), especially Ti3O. Despite focal adhesion on the surfaces, viability was different after 24 h, as cell viability on the oxidized surface was higher than on the nitrided surface (9.1 × 103 vs. 4.5 × 103cells; p < 0.05). This can be explained by analyzing the viscoelastic property of the cellular cytoskeleton (nuclear and peripheral) by AFM. Surface oxidation significantly increased RAECs viscoelasticity at cell periphery, in comparison to the nucleus (2.36 ± 0.3 vs. 1.5 ± 0.4; p < 0.05), and to the RAECs periphery in contact with nitrided surfaces (1.36 ± 0.7; p < 0.05) and polished surfaces (1.55 ± 0.6; p < 0.05). Taken together, our results have shown that titanium plasma treatment directly increased cell viscoelasticity via surface oxidation, and this mechanobiological property subsequently increased biocompatibility.

The research of the interaction between bacteria-surface has great importance for titanium biomedical applications once microorganisms offer risks because promoting implant loss. Therefore, study bacterial adhesion and colonization on titanium is interesting because are principal factors infections pathogeny on biomaterials. In this study, commercial grade II titanium was submitted to nitriding treatment to plasma at 2.2 mbar, using gas mixtures of 80% hydrogen (H2) and 20% nitrogen (N2) during 1 hour and 3 hour. The surfaces were physically and chemically characterized. In order to evaluate bacterial response, the surfaces were exposed to Pseudomonas aeruginosa. The titanium surface modified in nitriding plasma, although exposes a higher roughness as compared with untreated samples, exhibited lower bacterial growth. The nitrided sample for 3 hour exhibited the higher amount of TiN phase and the higher concentration of atomic nitrogen on surface and lower bacterial adhered count. These results were confirmed by scanning electron microscopy. Based on these results can be said to the thermochemical treatment of plasma nitriding on titanium samples results a significant reduction of adherence of Pseudomonas aeruginosa. It was found that the Ti surface nitrided offers significant reduction of bacterial adherence which prevent biofilm formation and offersing lower risk of infection and implant remotion.

There is a growing quest for an ideal biomaterial that shows appropriate cellular response and is not susceptible to microbial adhesion. In this study, commercial grade II titanium was submitted to RF/DC plasma surface modification at 2.2 mbar, using gas mixtures of argon, nitrogen, and oxygen at proportions 4:1:2 and 4:1:3. The surfaces were physically and chemically characterized. In order to evaluate bacterial response, the surfaces were exposed to Staphylococcus epidermidis. Oxynitrided samples, although having a higher roughness as compared with untreated samples, exhibited lower bacterial growth. This observation is probably due to the formation of different crystalline phases of nitrides and oxides caused by plasma treatment. The surface with highest contact angle and highest surface tension showed lower bacterial adhesion. These results were confirmed by scanning electron microscopy. The role of nitrogen in reducing bacterial adhesion is clear when this material is compared with untreated titanium, on which only an oxide film is present.

Bacterial adhesion on three different surfaces: untreated Ti, plasma nitriding, and plasma carbonitriding Ti substrates were investigated. The samples were placed in bacterial cultures of Pseudomonas aeruginosa to assess biofilm formation. The correlation between the amount of bacteria attached to the surface after a lapse of time with nanotopography and physicochemical properties was performed. TiN showed the highest capacity to avoid bacterial adhesion, while presenting intermediate roughness and wettability. Although the surface of TiCN had the highest surface roughness and low contact angle (high wettability), bacterial adhesion was intermediate on this sample. Untreated Ti, even though presenting a smooth surface and low wettability, had the highest tendency to form biofilms.

Cathodic cage discharge was developed recently in order to eliminate phenomena as edge effect and overheating, which occurs during conventional processes. In this study, the effect of cage configuration in active species during the deposition process and optical properties of TiN film were studied. TiN compound was chosen because its optical properties are very sensitive to slight variations in microstructure and film thickness, becoming a good monitoring tool in fabrication process control. Cages were made of titanium and have different holes numbers and holes diameter. Electrical efficiency of the system and optical properties of TiN films were strongly influenced by experimental conditions. It was found that with more holes at the top of cage, deposition rate and crystallinity were higher, if compared to cages with a small number of holes at the top. On the other hand, the opposite behavior was observed when more holes were located at the sidewall of cage.

Highly-porous titanium was produced by metal injection molding (MIM) of feedstock containing potassium chloride particles as a space holder. Macroporosity was generated by dissolving the potassium chloride particles in water. Challenges for MIM of highly-porous parts include shape retention during debinding and sintering and achieving open surface porosity. This study demonstrates that plasma treatment can remedy both these effects for highly-porous titanium. Plasma treatment of unsintered MIM samples enables attaining porosities of up to 64% in combination with good dimensional accuracy. The effect of plasma treatment on the uptake of interstitial impurities, dimensional accuracy, sintered microstructure and porosity, as well as the interaction of the plasma with partially-debinded MIM samples, was investigated. Highly-porous titanium produced by MIM and plasma treatment is attractive for biomedical implants due to its low impurity content, good dimensional accuracy and shape stability in combination with enhanced open porosity, the latter contributing to bone ingrowth and implant fixation.

There is a need for new techniques that modify metallic implant surfaces, resulting in good bone response for low density areas. Among the different techniques, plasma nitriding is being applied in biomedicine with excellent results. However, its use in titanium dental implants is very limited owing to high process temperatures (between 700 and 800°C) that result in distortions. In order to solve this problem, the authors used a new plasma method with a hollow cathode discharge configuration. Ti grade II dental implants were nitrided in a 20% N2–H2 atmosphere at a temperature of 450°C, 150 Pa (1·5 mbar), for 1 h and inserted into rabbit tibias to assess osseointegration. The results showed that plasma nitriding caused a significant change in the surface texture of the nitrided implants and greater removal torque than that of the control implants.

Titanium (Ti) is currently the most widely used material for the manufacture of orthopedic and dental implants. Changes in the surface of commercial pure Ti (cp Ti) can determine the functional response of cells, and is therefore a critical factor for the success of the implant. However, the genotoxicity of titanium surfaces has been poorly studied. Thus, the purpose of this study was to evaluate the genotoxic potential of a new titanium surface developed by plasma treatment using argon-ion bombardment and compare it with an untreated titanium surface. Accordingly, comet assay, analysis of chromosomal aberrations (CAs), and Cytokinesis Block Micronucleus (CBMN) assay were carried out, using CHO-K1 (Chinese hamster ovary) cells grown on both titanium surfaces. Our results show that the untreated titanium surface caused a significant increase in % tail moment, in the number of cells with CAs, tetraploidy, micronucleus frequency, and other nuclear alterations when compared with the negative control and with the plasma-treated titanium surface. This difference may be attributed to increased surface roughness and changes in titanium oxide layer thickness.

In recent years, several technologies that modify implant surfaces have been emerged. Among these techniques, the plasma nitriding process has been successfully applied in biomedical field. Nevertheless, its use in dental implants is quite limited owing to the high temperatures of the process (between 700 and 800°C), which causes distortion. In order to solve this problem, a new approach is proposed in the present paper, by which nitriding under a hollow cathode discharge is used to modify surfaces. Grade II Ti plates were submitted to nitriding under hollow cathode discharge conditions and treated at a temperature 450°C and pressure of 150 Pa for 1 h. These showed that plasma nitriding helped bring about a significant change in the surface texture of the treated plates. Furthermore, cell proliferation was 2⋅5 times as high as that of the untreated plates.

Thin films of titanium were deposited onto Al2O3 substrate by hollow cathode discharge method for the formation of a ceramic-ceramic joint using indirect brazing method. An advantage of using this technique is that a relatively small amount of titanium is required for the metallization of the ceramic surface when compared with other conventional methods. Rapidly solidified brazing filler of Cu49Ag45Ce6 in the form of ribbons was used. The thickness of deposited titanium layer and the brazing temperature/time were varied. The quality of the brazed joint was evaluated through the three point bending flexural tests. The brazed joints presented high flexural resistance values up to 176 MPa showing the efficiency of the technique.

There is a growing quest for an ideal biomaterial that shows appropriate cellular response and is not susceptible to microbial adhesion. In this study, commercial grade II titanium was submitted to RF/DC plasma surface modification at 2.2 mbar, using gas mixtures of argon, nitrogen, and oxygen at proportions 4:1:2 and 4:1:3. The surfaces were physically and chemically characterized. In order to evaluate bacterial response, the surfaces were exposed to Staphylococcus epidermidis. Oxynitrided samples, although having a higher roughness as compared with untreated samples, exhibited lower bacterial growth. This observation is probably due to the formation of different crystalline phases of nitrides and oxides caused by plasma treatment. The surface with highest contact angle and highest surface tension showed lower bacterial adhesion. These results were confirmed by scanning electron microscopy. The role of nitrogen in reducing bacterial adhesion is clear when this material is compared with untreated titanium, on which only an oxide film is present.

To evaluate the effect of topography in nanoscale, titanium surfaces were bombarded by argon ions (a chemically inert gas), in an atmosphere of plasma. The effects of surface parameters on morphology, adhesion, proliferation, and MC3T3-E1 preosteoblasts differentiation were analyzed. Nontreated (smooth) surfaces were used as a control. The levels of average roughness (Ra) observed in bombarded and smooth titanium surfaces were of 95 and 14 nm, respectively. The wettability increased on treated surfaces. The number of attached cells (30 and 60 min) was significantly higher on the bombarded surface. The cell proliferation after 3 and 7 days was also significantly higher on the ion-bombarded surface. In addition, the ALP activity and expression of osteocalcin were higher in cells grown on the treated surface. The results showed that bombardment with argon ions increased the roughness and the wettability of the Ti surface, promoting a significant increase in the adhesion, proliferation, and differentiation of preosteoblasts.

As intensidades de emissão das espécies N2+, H, C, NH, N2, Ar e CN do plasma de carbonitretação (usando os gases Ar+N2+CH4) foram medidas por espectroscopia de emissão óptica (OES) em pressão e temperatura constantes (2mbar e 500 °C) variando o fluxo de CH4. Em seguida, amostras de Ti comercialmente puro (Ti CP) foram carbonitretadas em plasma nas mesmas condições do estudo por OES. O objetivo desse trabalho é avaliar a influência das espécies presentes no plasma, detectadas por seus padrões de emissão, na composição de fases superficiais, nas características topográficas e no perfil de microdureza do revestimento de TiCN. Foi observado que o aumento da concentração de CH4 no plasma gerou as espécies H (dissociado do CH4) N2+, C, NH e CN. A evolução contínua de CN e uma queda progressiva na espécie N2+ influenciaram a composição da superfície e as propriedades aqui avaliadas. A análise de difração de raios X em ângulo rasante revelou a presença de nitreto e carbonitreto de titânio na superfície com composição química correlacionada com as alterações das intensidades de emissão das espécies CN e N2+. As topografias das amostras, avaliadas por microscopia de força atômica, apresentaram aumento nos parâmetros de rugosidade comparados com a amostra padrão. A rugosidade Ra aumentou com o aumento da intensidade de emissão óptica de CN e redução de N2+. Com auxílio da espectroscopia micro-Raman foi encontrado carbono não reagido com o titânio na forma de um filme que se desenvolveu com o aumento da intensidade da linha de emissão do CN. Este filme pode, hipoteticamente, ter sido o responsável pela queda progressiva da dureza superficial do revestimento. The optical emission intensities of the species N2+, H, C, NH, N2, Ar e CN in a carbonitriding plasma (using Ar+N2+CH4 gases) were studied with optical emission spectroscopy in an atmosphere of constant pressure and temperature, changing the CH4 flow. Afterwards a commercially pure Ti was exposed to a carbonitriding plasma in similar conditions. The objective of this work is to evaluate the influence of the gaseous species on the superficial properties (chemical composition, topography, and microhardness profile) of the TiCN layer. When the CH4 flow was increased, the species H, N2+, C, NH, and CN were observed. The continuous increase of CN and a progressive reduction of N2+were detected. Grazing incidence X-ray diffraction revealed titanium nitride and carbonitride with variable chemical compositions, related to the changes observed in the emission patterns of the species CN and N2+. The topography, evaluated by atomic force microscopy, showed that the roughness increased when CN increased and N2+ decreased. Micro-Raman spectroscopy showed unreacted carbon on the surface that developed with de increase of the CN emission. This carbon film may be responsible for the progressive decrease of surface hardness.

For titanium implants, a final porosity in the range of 60–65 vol% is required to achieve a network of interconnected macropores, which enables adequate fixation of the implant to the bone tissue and suitable mechanical properties. In addition, an open porosity at the implant surface is crucial for the success of the implant. In the present study, highly porous titanium foams were produced by warm compaction of MIM feedstock with the addition of space holder in a heatable die. Plasma treatment was performed on the Ti foams before the final sintering step aiming to increase the open pores at the surface. The results obtained so far demonstrate that plasma treatment is a promising technique for increasing open porosity at the surface. It even improved the dimensional accuracy of highly porous samples.

In the present work we use a plasma jet system with a hollow cathode to deposit thin TiO 2 films on silicon substrates. The cylindrical cathode, made from pure titanium, can be negatively polarized between 0 and 1200 V and supports an electrical current of up to 1 A. An Ar/O 2 mixture, with a total flux of 20 sccm and an O 2 percentage ranging from 0 to 20%, is passed through a cylindrical hole machined in the cathode. The influence of the cathode's parameters on the properties of deposited TiO 2 films and their deposition rate is studied. When discharge occurs, titanium atoms are sputtered/evaporated. They are transported by the jet and deposited on the Si substrates located on the holder placed facing the plasma jet system at a distance ranging from 10 to 50 mm from the cathode. The working pressure is 10 − 3 mbar and the deposition time is 10–60 min. The deposited films are characterized by X-ray diffraction to analyze qualitatively the phases present.

Standard plasma nitriding of commercially pure Ti or various Ti alloys for human body implants (e.g., hip, knee, shoulder and ankle implants) has already proven useful. However, its use in dental implantology is rather limited due to high nitriding temperatures. The small dental implants of complex geometries are frequently distorted. To solve this problem and benefit from the ability of the plasma treatment to modify the implant surface properties (needed for faster osseointegration process), such as creating different surface topographies, increasing surface roughness, changing local chemical properties by formation of different phases, cleaning/sterilizing contaminated surface and increasing the surface wettability, the titanium disk samples and industrial dental implants were nitrided using a hollow cathode discharge (HCD) configuration of a plasma nitriding system in a 20% N2–H2 atmosphere at pressures of 150 or 250 Pa and temperatures ranging from 400 to 500 °C for 1 or 2 h. The topography of the samples was characterized by optical and electron microscopy. Phases were determined by X-ray diffraction. The surface roughness and wettability were also quantified. Nitrided layer formation having better stability, increased surface roughness and higher wettability has been observed for samples treated at 450 and 500 °C and at a pressure of 150 Pa. Industrially fabricated dental implants were then nitrided at 500 °C/150 Pa for 2 h. The results show capability of HCD in treating dental implants. A significant change in the surface texture and superior wettability of the plasma-treated dental implants, with no geometric distortions, have been observed.

Aim: To evaluate the proliferative capacity of mesenchymal cells derived from human periodontal ligament on polished and plasma-treated titanium surfaces. Methods: Eighteen titanium disks were polished and half of them (n=9) were submitted to plasma nitriding using the cathodic cage technique. Mesenchymal cells were isolated from periodontal ligament of impacted third molars (n=2) and cultured on titanium disks (polished and nitrided) and on a plastic surface as a positive control of cell proliferation. Cell proliferation was analyzed and growth curves were constructed for the different groups by determining the number of cells adhered to the different surfaces at 24, 48 and 72 h after plating. Results: Higher cell number was observed for the nitrided surface at 24 and 48 h. However, no statistically significant difference in cell proliferation was observed between the two different surface treatments (p>0.05). Conclusions: We concluded that plasma nitriding produced surfaces that permitted the proliferation of human periodontal ligament mesenchymal cells. Associated to other physical and chemical properties, it is possible to assume the feasibility of plasma nitriding method and its positive effect on the early cellular events of osseointegration.

Se ha investigado la producción de titanio metálico (Ti) mediante de la reducción de óxido de titanio (TiO2) por técnica de reducción aluminotérmica, usando plasma de hidrógeno como desencadenante de la reacción. El polvo de TiO2 y Al utilizados se procesaron previamente por molienda de alta energía durante 4, 6 y 10 h. Se realizó también un estudio de análisis térmico, con el objetivo de conocer la temperatura de reacción para el proceso aluminotérmico de la mezcla TiO2-Al. El producto obtenido fue caracterizado mediante difractometría de rayos y microscopia electrónica de barrido, y se usó el método Rietveld para el refino en la determinación de la estructura. Los resultados comprueban la existencia de titanio metálico en el producto de la reacción aluminotérmica, cuando se utiliza el proceso de plasma The production of metallic titanium (Ti) through the reduction of titanium oxide (TiO2) by aluminothermic reduction technique, using hydrogen plasma to trigger the reaction has been investigated. Titanium oxide and aluminum powders were previously processed by high energy grinding during 4, 6 and 10h. Also, a thermal analysis study was done to know the temperature for the aluminothermic process in TiO2-Al mixtures. The product obtained was characterized by X-ray diffraction and scanning electron microscopy and Rietveld method was used in the microstructure refinement. The results show that is possible to obtain a titanium rich compound through the hollow cathode plasma technique.

Se ha investigado la producción de titanio metálico (Ti) mediante de la reducción de óxido de titanio (TiO2) por técnica de reducción aluminotérmica, usando plasma de hidrógeno como desencadenante de la reacción. El polvo de TiO2y Al utilizados se procesaron previamente por molienda de alta energía durante 4, 6 y 10 h. Se realizó también un estudio de análisis térmico, con el objetivo de conocer la temperatura de reacción para el proceso aluminotérmico de la mezcla TiO2-Al. El producto obtenido fue caracterizado mediante difractometría de rayos y microscopia electrónica de barrido, y se usó el método Rietveld para el refino en la determinación de la estructura. Los resultados comprueban la existencia de titanio metálico en el producto de la reacción aluminotérmica, cuando se utiliza el proceso de plasma. The production of metallic titanium (Ti) through the reduction of titanium oxide (TiO2) by aluminothermic reduction technique, using hydrogen plasma to trigger the reaction has been investigated. Titanium oxide and aluminum powders were previously processed by high energy grinding during 4, 6 and 10h. Also, a thermal analysis study was done to know the temperature for the aluminothermic process in TiO2-Al mixtures. The product obtained was characterized by X-ray diffraction and scanning electron microscopy and Rietveld method was used in the microstructure refinement. The results show that is possible too btain a titanium rich compound through the hollow cathode plasma technique.

With the aim of studying the topographic influence on wettability of plasma-treated surfaces, we used eighteen commercially pure titanium (CP Titanium) disks (grade II), 10 mm in diameter and 1 mm thick, and in atmospheres of Argon (Ar), Hydrogen H 2 and Ar–H 2 . These samples were submitted to plasma produced by hollow cathode discharge (HCD) for 20 and 60 min at a voltage of 500 V and pressure of 220 Pa. After pre-treatment, the state of the sample surfaces was assessed for surface phases with grazing incidence X-ray diffraction (GIXRD), and XPS (X-ray photoelectron spectroscopy), evaluated by atomic force microscopy (AFM) and wettability, using the sessile drop test. It was found that all the conditions were effective in reducing oxide, resulting in different wettability values. Correlation between average roughness (Ra) parameters and the ratio between maximum peak height and average distance between the highest peak and lowest valley (Rp/Rz) and wettability for the different treatment conditions were analyzed. Given the results obtained, it was concluded that Ra and Rp/Rz are not appropriate for correlating with wettability and it is suggested that a new topographic parameter be adopted for the Cassie–Baxter equation. XPS analysis showed that reduction efficacy was greater for the Ar–H 2 mixture, followed by Ar and H 2 .

In this study, we evaluated the effect of new plasma-nitrided Ti surfaces on the progression of osteoblast cultures, including cell adhesion, proliferation and differentiation. Ti surfaces were treated using two plasma-nitriding protocols, hollow cathode for 3 h (HC 3 h) and 1 h (HC 1 h) and planar for 1 h. Untreated Ti surfaces were used as control. Cells derived from human alveolar and rat calvarial bones were cultured on Ti surfaces for periods of up to 14 days and the following parameters were evaluated: cell morphology, adhesion, spreading and proliferation, alkaline phosphatase (ALP) activity, extracellular matrix mineralization, and gene expression of key osteoblast markers. Plasma-nitriding treatments resulted in Ti surfaces with distinct physicochemical characteristics. The cell adhesion and ALP activity were higher on plasma-nitrided Ti surfaces compared with untreated one, whereas cell proliferation and extracellular matrix mineralization were not affected by the treatments. In addition, the plasma-nitrided Ti surfaces increased the ALP, reduced the osteocalcin and did not affect the Runx2 gene expression. We have shown that HC 3 h and planar Ti surfaces slightly favored the osteoblast differentiation process, and then these surfaces should be considered for further investigation using preclinical models.

The aim of this study was to evaluate the characteristics of various titanium surfaces modified by cold plasma nitriding in terms of adhesion and proliferation of rat osteoblastlike cells.Samples of grade 2 titanium were subjected to three different surface modification processes: polishing, nitriding by plasma direct current, and nitriding by cathodic cage discharge. To evaluate the effect of the surface treatment on the cellular response, the adhesion and proliferation of osteoblastlike cells (MC3T3) were quantified and the results were analyzed by Kruskal-Wallis and Friedman statistical tests. Cellular morphology was observed by scanning electron microscopy.There was more MC3T3 cell attachment on the rougher surfaces produced by cathodic cage discharge compared with polished samples (P.05).Plasma nitriding improves titanium surface roughness and wettability, leading to osteoblastlike cell adhesion.

Titanium samples have been used as the substrate that was submitted to a plasma discharge nitriding for the surface treatment of dental implants. Two different arrangements regarding the electrode shapes were tested: planar and hollow cathode. The treated samples were evaluated regarding surface phases, texture, roughness, layer thickness, wettability and visual appearance. The roughness of the surface of all samples submitted to the plasma nitriding process was lower compared to those treated by commercially available technology plasma spray, on the other hand, better wettability was achieved. Some commercially available implants were also treated under the best conditions found with the experiment at titanium samples. After plasma nitriding these implants, tests were carried out to evaluate both wettability and surface texture. As a result the treated implants had both their surface texture and wettability improved.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior Plasma diagnostics by Optical Emission Spectroscopy were performed for electrical discharge in three gas mixture respecting the combinations z N2 y Ar x H2, z N2 y Ar x O2 e z N2 y Ar x CH4, in which the indexes z and y systematically vary from 1 to 4 and x varies from 0 to 4, every one has dimension SCCM, resulting in 80 combinations. From the all obtained spectrums, the species CH (387,1 nm), N2+ (391,4 nm), Hβ (486,1 nm), Hα (656,3 nm), Ar (750,4 nm), O (777,4 nm) e O (842,6 nm) were analyzed because of their abundance and importance on the kinetic of reaction from the plasma to surface, besides their high dependences on the gases flows. Particularly interesting z, y and x combinations were chosen in order to study the influence of active species on the surface modification during the thermochemical treatment. From the mixtures N2 Ar O2 e N2 Ar CH4 were chosen three peculiar proportions which presented luminous intensity profile with unexpected maximum or minimum values, denominated as plasma anomaly. Those plasma concentrations were utilized as atmosphere of titanium treatment maintaining constant the control parameters pressure and temperature. It has been verified a relation among luminous intensity associated to N2+ and roughness, nanohardness and O atoms diffusion into the crystalline lattice of treated titanium and it has been seen which those properties becomes more intense precisely in the higher points found in the optical profile associated to the N2+ specie. Those parameters were verified for the mixture which involved O2 gas. For the mixture which involves CH4 gas, the relation was determinate by roughness, number of nitrogen and carbon atoms diffused into the titanium structure which presented direct proportionality with the luminous intensity referent to the N2+ and CH. It has been yet studied the formation of TiCN phases on the surface which presented to be essentially directly proportional to the increasing of the CH specie and inversely proportional to the increasing of the specie N2+ Diagnósticos de plasma por Espectroscopia de Emissão Óptica foram realizados para descarga elétrica em três misturas gasosas, dentro das seguintes combinações: z N2 y Ar x H2, z N2 y Ar x O2 e z N2 y Ar x CH4, com os índices z e y variando sistematicamente de 1 a 4 e x de 0 a 4, todos com dimensão de SCCM, resultando em 80 combinações. Dos espectros obtidos, foram analisadas as espécies CH (387,1 nm), N2+ (391,4 nm), Hβ (486,1 nm), Hα (656,3 nm), Ar (750,4 nm), O (777,4 nm) e O (842,6 nm) por serem mais abundantes e importantes na cinética de reação do plasma à superfície, além de suas altas dependências dos fluxos de gás. Foram escolhidas combinações z, y e x, particularmente interessantes para estudar a influência das espécies ativas na modificação da superfície durante o tratamento termoquímico. Das misturas N2 Ar O2 e N2 Ar CH4 foram escolhidas três proporções peculiares que apresentavam perfis de intensidade luminescente com máximos ou mínimos inesperados classificados aqui como anomalias de plasma. Essas concentrações de plasma foram utilizadas como atmosfera de tratamento de amostras de titânio, mantendo-se constante os parâmetros pressão e temperatura. Verificou-se relação entre intensidade luminosa associada à espécie N2+ e a rugosidade, nanodureza e a difusão do oxigênio na rede cristalina do titânio tratado e viu-se que essas propriedades se intensificam precisamente nos pontos de máximo encontrados no perfil óptico dessa espécie. Esses parâmetros foram verificados para mistura que envolvia o gás O2. Para a mistura em que se fez presente o gás CH4, a relação foi determinada por meio da rugosidade, número de átomos de nitrogênio e carbono difundidos no titânio, que apresentou proporcionalidade direta com a intensidade luminosa referente às espécies N2+ e CH. Ainda foi estudada a formação de fases TiCN na sua superfície, que essencialmente se mostra diretamente proporcional ao crescimento da espécie CH e inversamente proporcional ao crescimento da espécie N2+

This work aims to develop a methodology for analysis of images using overlapping, which assists in identification of microstructural features in areas of titanium, which may be associated with its biological response. That way, surfaces of titanium heat treated for 08 (eight) different ways have been subjected to a test culture of cells. It was a relationship between the grain, texture and shape of grains of surface of titanium (attacked) trying to relate to the process of proliferation and adhesion. We used an open source software for cell counting adhered to the surface of titanium. The juxtaposition of images before and after cell culture was obtained with the aid of micro-hardness of impressions made on the surface of samples. From this image where there is overlap, it is possible to study a possible relationship between cell growth with microstructural characteristics of the surface of titanium. This methodology was efficient to describe a set of procedures that are useful in the analysis of surfaces of titanium subjected to a culture of cells O presente trabalho tem como objetivo desenvolver uma metodologia de análise de imagens, utilizando sobreposições, que auxilie na identificação de características microestruturais, em superfícies de titânio, que possam estar associadas com a sua resposta biológica. Desse modo, superfícies de titânio tratadas termicamente de 08(oito) diferentes maneiras foram submetidas a um ensaio de cultura de células. Buscou-se uma relação entre os grãos, textura e contornos de grãos da superfície de titânio (atacada) procurando relacionar com o processo de proliferação e adesão. Foi utilizado um software open source para a contagem das células aderidas à superfície do titânio. A justaposição das imagens antes e após a cultura de células foi obtida com o auxílio de impressões de micro-dureza feita sobre a superfície das amostras. A partir desta imagem onde há a sobreposição, é possível o estudo de uma possível relação entre o crescimento celular com as características microestruturais da superfície de titânio. Essa metodologia se mostrou eficiente ao descrever um conjunto de procedimentos que são úteis na analise de superfícies de titânio submetidos a uma cultura de células

Conselho Nacional de Desenvolvimento Científico e Tecnológico Titanium is a biomaterial widely employed in biomedical applications (implants, prostheses, valves, stents). Several heat treatments are usually used in order to obtain physical properties required to different applications. This work studied the influence of the heat treatment on microstructure of commercial pure titanium, and their consequences in growth and proliferation of MC3T3-E1 cells. Discs of titanium were treated in different temperatures, and characterized by optical microscopy, image analysis, wettabillity, roughness, hardness and X-ray diffraction. After the heat treatment, significant modifications in these properties were observed. Pattern images of titanium, before and after the cell culture, were compared by overlapping to analyze the influence of microstructure in microstructure and preferences guidance cells. However, in general, titanium discs that showed a higher residual strength also presented an increase of cells numbers on surface O titânio como biomaterial é amplamente utilizado em dispositivos biomédicos (implantes, próteses, válvulas, stents entre outros). Diversos tratamentos térmicos são usualmente utilizados na obtenção das propriedades necessárias para as diferentes aplicações. Este trabalho estudou a influência desses tratamentos na microestrutura do titânio comercialmente puro e suas conseqüências no crescimento, forma e proliferação de células pré-osteoblástica. Para tanto foram utilizados discos de titânio submetidos a diferentes tratamentos e caracterizados por microscopia ótica, análise de imagens, molhabilidade, rugosidade, dureza e difração de raios-X. Após os tratamentos térmicos foram verificado modificações significantes nestas propriedades. Padrões de imagens de superfícies do titânio antes e após a cultura de célula foram comparados através de sobreposição para analisar a influência da microestrutura na resposta biológica, não sendo verificadas correlações entre a microestrutura e as preferências orientacionais das células. Entretanto de um modo geral verificou-se que os discos que presentaram maior estado de tensão residual apresentaram também maior número de células em sua superfície