14 documents found, page 1 of 2
Multi-material cellular structured orthopedic implants design: In vitro and bio...
Costa, M.M.; Lima, R.; Alves, N.; Silva, N.A.; Gasik, M.; Bartolomeu, F.; Miranda, G.In this study, Selective Laser Melting (SLM) was used to produce mono-material Ti64Al4V- and NiTi-cubic cellular structures with an open-cell size and wall thickness of 500 μm and 100 μm, respectively. Bioactive beta-tricalcium phosphate (βTCP) and polymer poly-ether-ether ketone (PEEK) were used to fill the produced structures open-cells, thus creating multi-material components. These structures were character...
NiTi laser textured implants with improved in vivo osseointegration: an experim...
Costa, M.M.; Miranda, A.; Bartolomeu, F.; Carvalho, O.; Matos, S.; Miranda, Georgina; Silva, F.S.Laser surface texturing is a versatile approach for manufacturing implants with suitable surfaces for osseointegration. This work explores the use of laser to fabricate NiTi textured implants, testing two different groove-based designs. Their performance was evaluated in vivo through implantation in Sprague Dawley rats’ femur, being then analyzed after 4 and 12 weeks of implantation. Push-out experiments and hi...
Effect of Dietary Laminaria digitata with Carbohydrases on Broiler Production P...
Costa, M.M.; Pestana, José; Osório, Diogo; Alfaia, Cristina; Martins, Cátia Falcão; Mourato, M.; Rego, Andreia; Lemos, J. P. C.; Fontes, Carlos M.G.A.ABSTRACT - We hypothesized that dietary inclusion of 15% Laminaria digitata, supplemented or not with carbohydrases, could improve the nutritional value of poultry meat without impairing animal growth performance. A total of 120 22-day old broilers were fed the following dietary treatments (n = 10) for 14 days: cereal-based diet (control); control diet with 15% L. digitata (LA); LA diet with 0.005% Rovabio® Exc...
Engineering the elastic modulus of NiTi cellular structures fabricated by selec...
Bartolomeu, F.; Costa, M.M.; Alves, N.; Miranda, G.; Silva, F.S.Nickel-titanium (NiTi) cellular structures are a very promising solution to some issues related to orthopaedic implant failure. These structures can be designed and fabricated to simultaneously address a combination of mechanical and physical properties, such as elastic modulus, porosity, wear and corrosion resistance, biocompatibility and appropriate biological environment. This ability can enhance the modest ...
Additive manufacturing of NiTi-Ti6Al4V multi-material cellular structures targe...
Bartolomeu, F.; Costa, M.M.; Alves, N.; Miranda, G.; Silva, F.S.The amount of hip revision surgeries is significantly increasing due to the loss of fixation between implant and bone, that leads to implant failure. The stiffness mismatch between Ti6Al4V hip implants and bone tissue, the non-uniform implant-bone contact pressure, and the poor wear resistance of Ti6Al4V are pointed as three critical issues that contribute to these implant’s failure. In this study, a multi-mate...
Development of β-TCP-Ti6Al4V structures: Driving cellular response by modulatin...
Costa, M.M.; Lima, R.; Melo-Fonseca, F.; Bartolomeu, F.; Alves, N.; Miranda, A.; Gasik, M.; Silva, F.S.; Silva, N.A.; Miranda, G.Load-bearing implants success is strongly dependent on several physical and chemical properties that are known to drive cellular response. In this work, multi-material β-TCP-Ti6Al4V cellular structures were designed to combine Ti6Al4V mechanical properties and β-Tricalcium Phosphate bioactivity, in order to promote bone ingrowth as the bioactive material is being absorbed and replaced by newly formed bone. In t...
Ti6Al4V-PEEK multi-material structures – design, fabrication and tribological c...
Bartolomeu, F.; Abreu, C.S.; Moura, C.G.; Costa, M.M.; Alves, N.; Silva, F.S.; Miranda, G.A multi-material concept that gathers Ti6Al4V and PEEK properties in a cellular structured component was designed, fabricated and investigated targeting hip implants. SLM and pressure assisted injection techniques were used to obtain Ti6Al4V-PEEK multi-material structures. Aiming to reproduce to some extension the tribological phenomena occurring during and after hip implant insertion, five tribological tests w...
Corrosion behaviour of PEEK or β-TCP-impregnated Ti6Al4V SLM structures targeti...
Costa, M.M.; Dantas, T.A.; Bartolomeu, F.; Alves, N.; Silva, F.S.; Miranda, G.; Toptan, F.Ti6Al4V cellular structures were produced by selective laser melting (SLM) and then filled either with beta-tricalcium phosphate (β-TCP) or PEEK (poly-ether-ether-ketone) through powder metallurgy techniques, to improve osteoconductivity and wear resistance. The corrosion behavior of these structures was explored considering its importance for the long-term performance of implants. Results revealed that the inc...
Tribological behavior of bioactive multi-material structures targeting orthoped...
Costa, M.M.; Bartolomeu, F.; Alves, N.; Silva, F.S.; Miranda, G.The following study proposes a multi-material solution in which Ti6Al4V cellular structures produced by Selective Laser Melting are impregnated with bioactive materials (hydroxyapatite or β-tricalcium phosphate) using press and sintering technique. To assess the tribological response of these structures, an alumina plate was used as a counterpart in a flat-on-flat reciprocating sliding test. Ti6Al4V cellular st...
Multi-material Ti6Al4V & PEEK cellular structures produced by Selective Laser M...
Bartolomeu, F.; Buciumeanu, M.; Costa, M.M.; Alves, N.; Gasik, M.; Silva, F.S.; Miranda, G.Ti6Al4V-alloy is commonly used in dental and orthopedic applications where tribochemical reactions occur at material/bone interface. These reactions are one of the main concerns regarding Ti6Al4V implants due to the generation of wear particles, linked to the release of metallic ions in toxic concentration which occurs when TiO2 passive film is destroyed by means of wear and corrosion simultaneously. In the pre...