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Os implantes dentários de titânio comercialmente puro (Ticp) grau 4 e os de titânio-alumínio-vanádio (Ti6Al4V) grau 5, possuem boas propriedades mecânicas. No entanto, algumas situações clínicas com restrição de espessura óssea impedem a utilização dos implantes com 3.75mm de diâmetro tradicionalmente fabricados em titânio 4 e que apresentam resistência mecânica testada em profusão. Como a liga de grau 5 possui superior resistência à tração e à fadiga, este estudo objetiva analisar a resposta óssea do titânio grau 4 e grau 5 em implantes curtos e estreitos através da análise do contato osso-implante (BIC) e da área de neoformação óssea. Para este fim, o presente estudo utilizou 15 coelhos da raça New Zealand, que receberam um total de trinta implantes divididos em suas tíbias direita e esquerda. Os implantes de grau 4 e de grau 5, com dimensões de 3.5x8mm e 2.9x7mm, respectivamente, foram fornecidos pela empresa NEODENT® (Curitiba-Brasil). Neste estudo, dois grupos foram formados, um com implantes de titânio grau 4 e outro com implantes de titânio grau 5, ambos contendo quinze implantes curtos e estreitos. Cortes histológicos foram realizados após duas semanas de osseointegração. Mensurações no analisador de imagens ImageJ foram feitas para verificar o BIC e a área de osso neoformado. Para a análise dos dados estatísticos, utilizou-se o teste t de Student para amostras independentes com nível de significância de p<0.05. Os resultados mostraram que não houve diferença estatisticamente significante entre os grupos nos dois tipos de análises. A média dos valores de BIC do titânio grau 4 obteve o valor médio mais alto de 56,53%, variando de 95,74% a 9,4%. O grupo de titânio grau 5 apresentou média de 50,63%, variando entre 84,3% e 13,12%. Com base em imagens com fluorescência, realizou-se análise da área óssea. O grupo de titânio grau 5 apresentou valor de 46,3% (variando entre 79% a 14,21%) em fluorescência, número ligeiramente maior do que o verificado no grupo de titânio grau 4 (44,73%, com variância entre 78,93% e 18,36%). Com isso, concluiu-se que implantes de titânio de grau 4 e de grau 5 obtiveram respostas biológicas equivalentes, quando avaliados o BIC e a área óssea neoformada. / Commercially pure titanium implants (Ticp) of degree IV and of titanium-aluminum-vanadium degree V have good mechanical properties. However some clinical situations with limited bone thickness preclude the use of traditionally implants with 3.75mm diameter made from titanium IV and present strength tested in profusion. In addition, degree V alloy shows higher resistance to traction and fatigue, this study aims to analyze the bone response to degree IV and degree V titanium in short and narrow implants with the same surface treatment through the analysis of the bone-to-implant contact (BIC) and the area of the new bone formation. For such purpose, this study used15 New Zealand white rabbits which had a total of thirty implants inserted in their right and left tibiae. Both degree IV and degree V implants, measuring 3.5x8mm and 2.9x7mm, respectively, were provided by dental implant manufacturer NEODENT® (Curitiba-Brazil). The implants were allocated into two distinct groups. Fifteen short and narrow implants of degree IV were utilized in a group, whereas fifteen short and narrow implants of degree V were employed in the other group. Histological sections samples were carried out after a two-week period of osseointegration. Subsequently, measurements were calculated using ImageJ software in order to verify the BIC and the area of the newly grown bone. Analysis of statistical data of independent samples with significance level p<0.05 was carried out via Student\'s t-test. Results showed no statistically substantial difference between both groups regarding both measurement activities. The media values BIC for the degree IV titanium group reached the highest average value of 56,53%, varying from 95,74% to 9,4%. The degree V titanium group averaged 50,63%, oscillating between 84,3% and 13,12%. The bone areas were analyzed based on images with fluorescence. The degree V titanium group reached the percentage of 46,3% (varying from 79% to 14,21%) in fluorescence whereas the degree IV titanium group had a percentage of 44,73% (varying between 78,93% and 18,36%). Therefore, both degree IV and degree V implants had equivalent biological responses based on the analysis of BIC and newly grown bone areas.

A realização do presente trabalho permitiu o estudo dos micromecanismos de deformação e fratura da liga de titânio Ti-6Al-4V, utilizada comercialmente para a fabricação de biomateriais metálicos. As técnicas empregadas para a análise do material em estudo foram: microscopia eletrônica de varredura (MEV), microscopia eletrônica de transmissão (MET) e a difração de raios X (DRX). Estudar a influência e comportamento das diversas fases existentes em ligas de titânio é importante para se avaliar o comportamento de trincas nas ligas de titânio com alta resistência mecânica, que possuem microestrutura fina, relacionando a presença das fases alfa (&alpha;), beta (&beta;) e alfa+beta (&alpha;+&beta;) com a resistência do material. A avaliação in situ dos micromecanismos de deformação e fratura foi realizada por MET e também foi feito o estudo das transformações de fase durante o resfriamento em ligas de titânio, por MET, utilizando-se as técnicas de campo claro, campo escuro e difração de elétrons (DEAS), em área selecionada. Após tratamento térmico foram observadas as diferenças entre a quantidade das fases &alpha; e &beta;, em relação à microestrutura original do material para diferentes condições utilizadas no tratamento térmico aplicado à liga metálica. Observou-se a presença da microestrutura lamelar, formada durante o resfriamento no campo &beta;, promovendo a transformação de parte da estrutura alfa secundária em beta, que se encontrava retida entre as lamelas de alfa. / This present work allowed the study of deformation and fracture micromechanisms of titanium alloy Ti-6Al-4V, used commercially for the manufacture of metallic biomaterials. The techniques employed for the analysis of the material under study were: scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The study of the influence and behavior of the phases present in titanium alloys is important to evaluate the behavior of cracks in titanium alloys with high mechanical strength, which have fine alpha (&alpha;), beta (&beta;) and alpha+beta (&alpha;+&beta;) microstructure, linking the presence of the phases with the strength of the material. The evaluation in situ of deformation and fracture micromechanisms were performed by TEM and was also a study of phase transformations during cooling in titanium alloys, using the techniques of bright field, dark field and diffraction of electrons in the selected area. After heat treatment differences were observed between the amount of in relation to the original microstructure of the &beta; and &alpha; phases material for different conditions used in heat treatment applied to the alloy. The presence of lamellar microstructure formed during cooling in the &beta; field was observed, promoting the conversion of part of the secondary alpha structure in &beta; phase, which was trapped between the lamellar of alpha.

The aims of this thesis are fabrication of Ti/APC-2 hybrid nanocomposite laminates and investigation of their mechanical properties at elevated temperature. The prepregs of APC-2 were stacked into cross-ply [0/90]s and quasi-isotropic [0/45/90/-45] laminates spread uniformly with nanoparticles SiO2. The sheet surface was treated by chromic acid anodic method to achieve perfectly bonding with matrix PEEK. The prepregs were sandwiched with the Ti alloy sheets. The modified diaphragm curing process was adopted to produce Ti/APC-2 hybrid nanocomposite laminates. The nanocomposite laminates were a five-layer composite with two 0.55 mm thick APC-2 layers sandwiched by three 0.5 mm thick Gr.1 titanium alloy sheets. The MTS 810 material testing machine was used to conduct the tension and fatigue tests. In addition, the MTS 651 environmental chamber was installed to control and keep the experimental temperature, such as 25¢XC, 75¢XC, 100¢XC, 125¢XC and 150¢XC. The mechanical proper&not;ties, such as ultimate tensile strength, longitudinal stiffness of cross-ply and quasi-isotropic nanocomposite laminates, were obtained from the static tensile test. The stress-strain diagrams were plotted in the corresponding temperature. The constant stress amplitude tension-tension cyclic tests were carried out by using load-control mode at a sinusoidal loading with frequency of 5Hz and stress ratio R=0.1. The received fatigue data were plotted in normalized S-N curves at variously elevated temperature. From the summarized results, some conclusions were made. First, the ultimate strength of Ti/APC-2 nanocomposits was better than Ti/APC-2 composites at room temperature; Second, Both two type nanocomposite laminates¡¦ ultimate strength and S-N curves go downwards as temperature rising, especially at 150¢XC; Third, The fatigue tensile strength of both hybrid composite laminates was the lowest at 150¢XC. Fourth, Ti/APC-2 quasi-isotropic nanocomposite laminates had better fatigue resistance than Ti/APC-2 cross-ply nanocomposite laminates. Finally,The longitudinal stiffness was in good agreement with prediction by using the modified ROM because of the changed curve fitting ranges.

The aims of this thesis to investigate the two step loading of Ti/APC-2 hybrid nanocomposite laminates and their notched effect. Ti/APC-2 laminates were composed of three layers of titanium sheets and two layers of APC-2. Nanoparticles SiO2 were dispersed uniformly on the interfaces of APC-2 with the optimal amount of 1 wt %. Then, APC-2 was stacked according to cross-ply [0/90]s and quasi-isotropic [0/45/90/-45] sequences. The modified diaphragm curing process was adopted to fabricate the hybrid panels for minimal impact of production. The panels were cur into samples and drilled an diameter hole in the center with diameters of 4 or 6 mm. Both tension and fatigue tests were carried out with MTS 810 universal testing machine at room temperature. Also, two-step loading tests include high¡÷low and low¡÷high tests, were conducted. 0.9£mnom is denoted as high load and 0.7£mnom low load for two-step loading spectrum. In both high¡÷low and low¡÷high step loadings the first step is to do cyclic tests at a half life of the corresponding load, and then finish it due to last step load. From the received results, some conclusions were made. First, the ultimate load of notched cross-ply samples was reduced about 50% and the notched quasi-isotropic samples reduced about 30% compared to their unnotched counterparts. Second, the S-N curves are very close for both centrally notched samples of diameters 4 mm and 6 mm in cross-ply and quasi-isotropic samples. Third, quasi-isotropic samples had higher average values of cumulative damage than cross-ply samples. Because of notched effect centrally notched samples of diameters 4 mm had higher average values of cumulative damage than centrally notched samples of diameters 6 mm.

Dans cette étude, nous avons combiné les bonnes propriétés mécaniques de l'alliage de titane Ti6Al4V avec les excellentes propriétés biologiques apportées par le greffage d’un polymère « bioactif » le poly(styrène sulfonate de sodium) (poly(NaSS)). Le greffage chimique du poly(NaSS) réalisé à partir de la surface de l'alliage a permis de générer des biomatériaux « fonctionnalisés » et « bioactifs ». Sur ces substrats, la réponse de cellules ostéoblastiques de la lignée MC3T3-E1 a été étudiée en présence et en absence de protéines d’intérêt (seules ou en mélange). Nous avons pu mettre en évidence l’effet de ces protéines, de leur conformation et de leur compétitivité sur la réponse cellulaire (adhésion, étalement, différenciation). Dans des conditions de culture sans sérum, la seule présence du poly(NaSS) améliore la réponse cellulaire en augmentant l’adhérence, l’étalement et en prolongeant la viabilité cellulaires. Nous avons montré qu’en présence du poly(NaSS) la Fn joue un rôle majeur dans l'attachement précoce des cellules quel que soit le milieu de culture même « déplété » en certaines protéines. D’autre part nous avons également montré que le poly(NaSS) modifie la conformation des protéines adsorbées en augmentant l'exposition de leurs sites de liaison « actifs », tels que le peptide RGD dans la molécule Fn favorisanr ainsi l’adhésion et la fixation cellulaires par le biais des intégrines. Entre toutes les protéines étudiées, Col I a été identifiée comme la protéine qui stimule de manière la plus significative la minéralisation de la matrice ostéoblastique, en augmentant l'activité de la phosphatase alcaline et la production de phosphate et de calcium. Les surfaces greffées de poly(NaSS) pré-adsorbées du mélange protéique Fn & Col I favorisent l'expansion cytoplasmique des ostéoblastes, leur force d'attachement, leur différenciation et leur minéralisation. La compétitivité des protéines Fn, Col I et BSA protéine a également été étudiée. En résumé, le poly(NaSS) greffé sur des surfaces de Ti6Al4V propose une solution prometteuse pour l'ostéointégration rapide des biomatériaux, avec des applications possibles dans les domaines orthopédiques et dentaires. / In this investigation, we combined the good mechanical properties of the titanium (Ti) alloy Ti6Al4V with the biological properties, namely bioactivity, of the polymer poly(sodium styrene sulfonate) (poly(NaSS)). By chemically grafting the poly(NaSS) on the surface of the Ti alloy we generated biofunctionalized biomaterials. On these substrates, the MC3T3-E1 osteoblast-like cells response was followed in the presence and absence of individual proteins and important information about the competitive behavior of proteins and their effect on the cell development was uncovered. In serum free medium conditions, poly(NaSS) influenced positively the cells response, by enhancing their attachment strength and by extending their viability and inherent morphology. Fn together with poly(NaSS) was found to play a major role in the cell early attachment, even when in double depleted medium. It was also seen, that poly(NaSS) alters the proteins conformation by increasing the exposure of active binding sites, such as the RGD peptide in the Fn molecule, and this way promoting integrin-mediated cell attachment. Between all proteins, Col I was found to stimulate more significantly the osteoblast-like cells matrix mineralization, by increasing the alkaline phosphatase activity and the calcium and phosphate productions. Grafted surfaces pre-adsorbed with Fn & Col I mixtures promoted the cell cytoplasmatic expansion, attachment strength, differentiation and mineralization. The competitive behavior of Fn and Col I was seen to prevail over BSA. In summary, the poly(NaSS) together with the Ti6Al4V material offers a promising solution for fast biomaterial osteointegration to be used in the orthopedic and dental fields.

A realização do presente trabalho permitiu o estudo dos micromecanismos de deformação e fratura da liga de titânio Ti-6Al-4V, utilizada comercialmente para a fabricação de biomateriais metálicos. As técnicas empregadas para a análise do material em estudo foram: microscopia eletrônica de varredura (MEV), microscopia eletrônica de transmissão (MET) e a difração de raios X (DRX). Estudar a influência e comportamento das diversas fases existentes em ligas de titânio é importante para se avaliar o comportamento de trincas nas ligas de titânio com alta resistência mecânica, que possuem microestrutura fina, relacionando a presença das fases alfa (&alpha;), beta (&beta;) e alfa+beta (&alpha;+&beta;) com a resistência do material. A avaliação in situ dos micromecanismos de deformação e fratura foi realizada por MET e também foi feito o estudo das transformações de fase durante o resfriamento em ligas de titânio, por MET, utilizando-se as técnicas de campo claro, campo escuro e difração de elétrons (DEAS), em área selecionada. Após tratamento térmico foram observadas as diferenças entre a quantidade das fases &alpha; e &beta;, em relação à microestrutura original do material para diferentes condições utilizadas no tratamento térmico aplicado à liga metálica. Observou-se a presença da microestrutura lamelar, formada durante o resfriamento no campo &beta;, promovendo a transformação de parte da estrutura alfa secundária em beta, que se encontrava retida entre as lamelas de alfa. / This present work allowed the study of deformation and fracture micromechanisms of titanium alloy Ti-6Al-4V, used commercially for the manufacture of metallic biomaterials. The techniques employed for the analysis of the material under study were: scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The study of the influence and behavior of the phases present in titanium alloys is important to evaluate the behavior of cracks in titanium alloys with high mechanical strength, which have fine alpha (&alpha;), beta (&beta;) and alpha+beta (&alpha;+&beta;) microstructure, linking the presence of the phases with the strength of the material. The evaluation in situ of deformation and fracture micromechanisms were performed by TEM and was also a study of phase transformations during cooling in titanium alloys, using the techniques of bright field, dark field and diffraction of electrons in the selected area. After heat treatment differences were observed between the amount of in relation to the original microstructure of the &beta; and &alpha; phases material for different conditions used in heat treatment applied to the alloy. The presence of lamellar microstructure formed during cooling in the &beta; field was observed, promoting the conversion of part of the secondary alpha structure in &beta; phase, which was trapped between the lamellar of alpha.

Os implantes dentários de titânio comercialmente puro (Ticp) grau 4 e os de titânio-alumínio-vanádio (Ti6Al4V) grau 5, possuem boas propriedades mecânicas. No entanto, algumas situações clínicas com restrição de espessura óssea impedem a utilização dos implantes com 3.75mm de diâmetro tradicionalmente fabricados em titânio 4 e que apresentam resistência mecânica testada em profusão. Como a liga de grau 5 possui superior resistência à tração e à fadiga, este estudo objetiva analisar a resposta óssea do titânio grau 4 e grau 5 em implantes curtos e estreitos através da análise do contato osso-implante (BIC) e da área de neoformação óssea. Para este fim, o presente estudo utilizou 15 coelhos da raça New Zealand, que receberam um total de trinta implantes divididos em suas tíbias direita e esquerda. Os implantes de grau 4 e de grau 5, com dimensões de 3.5x8mm e 2.9x7mm, respectivamente, foram fornecidos pela empresa NEODENT® (Curitiba-Brasil). Neste estudo, dois grupos foram formados, um com implantes de titânio grau 4 e outro com implantes de titânio grau 5, ambos contendo quinze implantes curtos e estreitos. Cortes histológicos foram realizados após duas semanas de osseointegração. Mensurações no analisador de imagens ImageJ foram feitas para verificar o BIC e a área de osso neoformado. Para a análise dos dados estatísticos, utilizou-se o teste t de Student para amostras independentes com nível de significância de p<0.05. Os resultados mostraram que não houve diferença estatisticamente significante entre os grupos nos dois tipos de análises. A média dos valores de BIC do titânio grau 4 obteve o valor médio mais alto de 56,53%, variando de 95,74% a 9,4%. O grupo de titânio grau 5 apresentou média de 50,63%, variando entre 84,3% e 13,12%. Com base em imagens com fluorescência, realizou-se análise da área óssea. O grupo de titânio grau 5 apresentou valor de 46,3% (variando entre 79% a 14,21%) em fluorescência, número ligeiramente maior do que o verificado no grupo de titânio grau 4 (44,73%, com variância entre 78,93% e 18,36%). Com isso, concluiu-se que implantes de titânio de grau 4 e de grau 5 obtiveram respostas biológicas equivalentes, quando avaliados o BIC e a área óssea neoformada. / Commercially pure titanium implants (Ticp) of degree IV and of titanium-aluminum-vanadium degree V have good mechanical properties. However some clinical situations with limited bone thickness preclude the use of traditionally implants with 3.75mm diameter made from titanium IV and present strength tested in profusion. In addition, degree V alloy shows higher resistance to traction and fatigue, this study aims to analyze the bone response to degree IV and degree V titanium in short and narrow implants with the same surface treatment through the analysis of the bone-to-implant contact (BIC) and the area of the new bone formation. For such purpose, this study used15 New Zealand white rabbits which had a total of thirty implants inserted in their right and left tibiae. Both degree IV and degree V implants, measuring 3.5x8mm and 2.9x7mm, respectively, were provided by dental implant manufacturer NEODENT® (Curitiba-Brazil). The implants were allocated into two distinct groups. Fifteen short and narrow implants of degree IV were utilized in a group, whereas fifteen short and narrow implants of degree V were employed in the other group. Histological sections samples were carried out after a two-week period of osseointegration. Subsequently, measurements were calculated using ImageJ software in order to verify the BIC and the area of the newly grown bone. Analysis of statistical data of independent samples with significance level p<0.05 was carried out via Student\'s t-test. Results showed no statistically substantial difference between both groups regarding both measurement activities. The media values BIC for the degree IV titanium group reached the highest average value of 56,53%, varying from 95,74% to 9,4%. The degree V titanium group averaged 50,63%, oscillating between 84,3% and 13,12%. The bone areas were analyzed based on images with fluorescence. The degree V titanium group reached the percentage of 46,3% (varying from 79% to 14,21%) in fluorescence whereas the degree IV titanium group had a percentage of 44,73% (varying between 78,93% and 18,36%). Therefore, both degree IV and degree V implants had equivalent biological responses based on the analysis of BIC and newly grown bone areas.