Functionally graded porous scaffolds made of Ti-based agglomerates

Nazari, Keivan A.; Hilditch, Tim; Dargusch, Matthew S.; Nouri, Alireza

doi:10.1016/j.jmbbm.2016.06.016

Cited by 27 publications

(10 citation statements)

References 17 publications

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“…Different methods have been introduced to control and reduce the stresses around the implant body. Examples of this are changes to the implant neck, design changes to the implant thread configurations, and implant surface modifications …”

Section: Implant Design and Load Transfermentioning

confidence: 99%

“…This is because these differences in roughness produce different friction coefficients, and those surfaces with higher friction coefficients are responsible for the bone‐implant interlocking, therefore favoring stress dissipation. Apparently rougher and porous titanium surfaces acquire elastic properties, closer to those of bone, and facilitate stress shielding at the surrounding bone . Meanwhile, smooth machined surfaces with low friction coefficients transfer more shear forces to the adjacent bone .…”

Section: Implant Design and Load Transfermentioning

confidence: 99%

“… Apparently rougher and porous titanium surfaces acquire elastic properties, closer to those of bone, and facilitate stress shielding at the surrounding bone . Meanwhile, smooth machined surfaces with low friction coefficients transfer more shear forces to the adjacent bone . Examples of different implant surfaces with differences in roughness are presented in Figure .…”

Section: Implant Design and Load Transfermentioning

confidence: 99%

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Effects of occlusal forces on the peri‐implant‐bone interface stability

Delgado-Ruíz

Calvo-Guirado

Romanos

2019

Periodontology 2000

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The Glossary of Prosthodontic Terms defines occlusion as the 'act or process of closure, being closed or shut off and the static relationship between the incising or masticating surfaces of the maxillary or mandibular teeth or tooth analogs'. 1 To achieve the dental occlusion, the skeletal and muscular systems work simultaneously to produce the mandibular movement, which transfers force to the prosthesis, teeth, implants, and adjacent supporting bone. 2 But the dental/implant occlusion is not just a simple contact between opposite surfaces. It is complex, and also includes the friction of multiple inclined planes and different force vectors (axial and nonaxial). 3 These force vectors occur simultaneously and are transient and therefore the concept of a unidirectional occlusal force should be replaced by the concept of multidirectional occlusal forces. 4 Additional forces of swallowing and sometimes parafunctions are applied to the system and overloading can appear. 2 Occlusal overload has been defined as the load greater than prostheses, implant components, or interface that tissues are capable of withstanding without damage. 1 For Laney, overload is occurring if the occlusal load exerted through function or parafunctions exceeds the resistance of the prosthesis, implant components, implant, and osseointegrated interface, resulting in structural or biological damage. 5 At the biological level, overload is produced when the amount of force overextends the adaptation capabilities of the host site. 6All the structures subject to occlusal forces can be exposed to physiological loading or overloading. 6 In the case of physiological loading, forces <3000 microstrains are dissipated through the occlusal surfaces, prosthetic structure, implant-abutment connection, retention screw, implant body, implant bone interface, and surrounding, supporting bone (Figure 1). 7 Meanwhile, overload strains >3000 microstrains might affect the weakest part of the system producing structural and/or biological failures. 8The applied occlusal bite forces are extremely difficult to quantify because they are not absolute and have great variability, which is influenced by factors such as duration, distribution, direction, and magnitude of forces. 9 Also, other factors such as the number and location of teeth and implants, their inclinations within the dental arch, the kind of restoration, and the bone quality can influence the resultant forces and therefore their accurate measurement. 10,11 In relation to the maximum biting forces produced in patients with osseointegrated implants, different magnitudes of occlusal forces have been recorded, with values ranging between 25 and 1000 N. [12][13][14][15][16][17][18][19][20][21][22][23] These studies agree that the forces transmitted by the anterior teeth are lower than those transmitted by the posterior teeth, that among the posterior teeth the second molar exerts the maximum levels of force, and that gender influences the bite force, with higher biting forces being generated by men compared with w...

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Section: Implant Design and Load Transfermentioning

confidence: 99%

Section: Implant Design and Load Transfermentioning

confidence: 99%

Section: Implant Design and Load Transfermentioning

confidence: 99%

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Effects of occlusal forces on the peri‐implant‐bone interface stability

Delgado-Ruíz

Calvo-Guirado

Romanos

2019

Periodontology 2000

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“…Titanium and its alloys exhibit frequent utilization in a wide range of application fields, from aircraft industry [1][2][3] to medicine [2][3][4]. Nowadays, titanium with commercial purity has been very popular for structural applications [4][5][6][7]. The main reason is that the impurities present in commercially pure titanium (mainly oxygen and iron) do not limit the possibility of medical application, unlike some other potentially harmful alloying elements.…”

Section: Introductionmentioning

confidence: 99%

Structure and Properties of High-Strength Ti Grade 4 Prepared by Severe Plastic Deformation and Subsequent Heat Treatment

et al. 2020

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Severe plastic deformation represented by three passes in Conform SPD and subsequent rotary swaging was applied on Ti grade 4. This process caused extreme strengthening of material, accompanied by reduction of ductility. Mechanical properties of such material were then tuned by a suitable heat treatment. Measurements of in situ electrical resistance, in situ XRD and hardness indicated the appropriate temperature to be 450 °C for the heat treatment required to obtain desired mechanical properties. The optimal duration of annealing was stated to be 3 h. As was verified by neutron diffraction, SEM and TEM microstructure observation, the material underwent recrystallization during this heat treatment. That was documented by changes of the grain shape and evaluation of crystallite size, as well as of the reduction of internal stresses. In annealed state, the yield stress and ultimate tensile stress decreased form 1205 to 871 MPa and 1224 to 950 MPa, respectively, while the ductility increased from 7.8% to 25.1%. This study also shows that mechanical properties of Ti grade 4 processed by continual industrially applicable process (Conform SPD) are comparable with those obtained by ECAP.

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“…One approach for obtaining stiffness gradation is the insertion of a porosity gradation in the piece. Orthopedic implants with a solid core and a porous surface are desirable when better biological fixation is required because a porous surface allows the growth of bone tissue through the pores [21,22]. Additionally, this configuration decreases the implant weight and the effective stiffness in the bone/implant contact zone.…”

Section: -Introductionmentioning

confidence: 99%

Less-rigid coating in Ti obtained by laser surface alloying with Nb

Carvalho

Sallica-Leva

Encinas

et al. 2018

Surface and Coatings Technology

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The fabrication of parts with stiffness gradation specifically designed to attain higher mechanical and/or biomedical performance is receiving increasing scientific and technological interest. This work reports the use of laser surface alloying to introduce Nb into the surface layer of Ti pieces and thus obtain continuous coatings composed of Ti-Nb alloys. By controlling the laser processing parameters, coatings with lower Young`s modulus and higher hardness compared to the substrate, practically free of cracks and with very low porosity were obtained, using energy densities in the range of 24 to 65 J/mm 2. However, compositional heterogeneity mainly due to microsegregation during the solidification process was observed. Increasing the energy density resulted in deeper fusion zones, which increased the substrate fusion and thus decreased the Nb content and produced a coating with a microstructure predominantly composed of α/α' acicular phase. On the other hand, the Nb content of the coatings produced with lower energy densities was high enough (~20-30 % in mass) to (meta)stabilize the less-rigid α'' and β phases, which promoted the highest reductions in the Young`s modulus of the investigated coatings. Besides the lower stiffness, all coatings presented at least twice the hardness of the substrate. Maps of the properties constructed from the nanoindentation results showed that, despite the compositional heterogeneity, homogenous values of Young`s modulus and hardness were attained and *Manuscript Click here to view linked References the change in the interface region was gradual, in agreement with the concept of functionally graded materials.

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Functionally graded porous scaffolds made of Ti-based agglomerates

Cited by 27 publications

References 17 publications

Effects of occlusal forces on the peri‐implant‐bone interface stability

Effects of occlusal forces on the peri‐implant‐bone interface stability

Structure and Properties of High-Strength Ti Grade 4 Prepared by Severe Plastic Deformation and Subsequent Heat Treatment

Less-rigid coating in Ti obtained by laser surface alloying with Nb

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