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Made available in DSpace on 2020-12-10T19:47:51Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-01-25 LORXI at UFPR, Brazil Hydroxyapatite (HA) is a bioactive calcium phosphate capable of enhancing the implant/bone connection improving osteoconductivity and osseointegration process. However, the HA presents mechanical properties limiting its application. A good way to resolve this limitation is to combine the excellent biological properties of HA with materials with suitable mechanical behavior, like Ti-25Nb-25Ta alloy. The Ti-25Nb-25Ta alloy is cornposted by non-toxic and corrosion-resistant elements, presenting good biological compatibility. In this work, Plasma Electrolytic Oxidation (PEO) (using direct current-DC) was applied in conventional mode and Two-Step PEO aiming to produce a porous coating containing HA. It was not possible to produce a satisfactory coating applying conventional PEO due to successive spalling during the oxidation process. Adding a pretreatment to the conventional PEO changed the process to Two -Step PEO allowing to form a porous coating containing HA. The pretreatment was made by PEO using phosphoric electrolyte to produce a pre-coating. After that, the pre-coating was re-oxidized with calcium/phosphorus electrolyte. The Two -Step oxidized surface presented well-known good characteristics to applications in osseous implant devices such as porous formation, roughness in the micrometrical range, surface containing calcium and phosphorus, bioactive crystalline titanium oxide, and well adhered HA formation. However, the coating morphology and chemical composition of pre-coating and Two Step oxidized surfaces were not uniform. The non-uniformity of the Two -Step oxidized surface follows a similar non-uniformity pattern of the pre-coating surface. Two distinct morphologies were identified on the Two-Step oxidized surface: a velvety morphology with HA formation and a highly porous morphology. Regarding the Ti-25Nb-25Ta alloy, the Two-Step oxidation produced an adhered coating with porous apatite distribution interspersed with calcium-rich porous oxide. Univ Fed Parana, Postgrad Program Mat Engn & Sci PIPE, Curitiba, Parana, Brazil Athlone Inst Technol, MRI, Athlone, Ireland Univ Tecnol Fed Parana, Dept Mech Engn Curitiba, Curitiba, Parana, Brazil Univ Fed Parana, Dept Phys, Curitiba, PR, Brazil Univ Estadual Paulista, Dept Mat & Technol, Guaratingueta, SP, Brazil Univ Estadual Paulista, Dept Mat & Technol, Guaratingueta, SP, Brazil LORXI at UFPR, Brazil: FINEP CT-INFRA 793/2004 LORXI at UFPR, Brazil: 3080/2011

The aim of this work was to evaluate the ability of a bioactive glass-ceramic to induce the apatite nucleation on the titanium oxide layer produced by micro-arc oxidation. “ In vitro ” tests were carried out on a simulated body fluid solution in two different manners: one group was soaked in the SBF, while the other group was soaked together with the bioactive glass-ceramic. Results revealed that after 7 days, the specimens soaked in SBF were covered with an amorphous calcium phosphate layer, while the specimens soaked in SBF plus glass-ceramic formed a crystalline apatite layer, suggesting thus, that the glass-ceramic provides silanol groups that accelerated the hydroxyapatite apatite precipitation on the anodic TiO 2 layer.