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Tribocorrosion of Porous Titanium Used in Biomedical Applications

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Arjun Manoj
Arjun Manoj
Arjun Manoj
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Ashish Kumar Kasar at University of Nevada, Reno
Ashish Kumar Kasar
Pradeep L Menezes at University of Nevada, Reno
Pradeep L Menezes
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Titanium and its alloys have become increasingly important in the dental and orthopedic fields due to its good machinability, high yield strength, good ductility, excellent corrosion resistance, and superior biocompatibility compared to other materials. However, an inherent drawback of using pure titanium and its alloys as implant material is the significant mismatch between the moduli of bone and titanium, resulting in the stress shielding effect, fibrous tissue ingrowth, and bone resorption, and therefore reducing the lifespan of the implant. Porous titanium is thus a suitable candidate as implant material due to its ability to be manufactured to a specific Young’s modulus—typically that of bone. Porous titanium has the unique advantage of allowing bone tissue ingrowth into the open space of the implants, thereby accelerating the osseointegration process. The human body as well as the oral cavity is a highly complex environment in which the simultaneous interaction between wear and corrosion, namely tribocorrosion, takes place. Thus, understanding these interactions is of great interest in order to characterize the degradation mechanisms of porous titanium materials used as implants. This paper reviews the state-of-the-art of porous titanium as a viable biomedical implant material. A significant part of this paper is focused on how porous titanium is manufactured and how its parameters are controlled. The following sections focus on the corrosion, wear, and tribocorrosion aspects of porous titanium implant materials. Finally, this review also determines the current limitations in the field and provides future directions in this field.
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Vol.:(0123456789)
1 3
Journal of Bio- and Tribo-Corrosion (2019) 5:3
https://doi.org/10.1007/s40735-018-0194-4
Tribocorrosion ofPorous Titanium Used inBiomedical Applications
ArjunManoj1· AshishK.Kasar1· PradeepL.Menezes1
Received: 31 July 2018 / Revised: 9 October 2018 / Accepted: 20 October 2018 / Published online: 30 October 2018
© Springer Nature Switzerland AG 2018
Abstract
Titanium and its alloys have become increasingly important in the dental and orthopedic fields due to its good machinability,
high yield strength, good ductility, excellent corrosion resistance, and superior biocompatibility compared to other materials.
However, an inherent drawback of using pure titanium and its alloys as implant material is the significant mismatch between
the moduli of bone and titanium, resulting in the stress shielding effect, fibrous tissue ingrowth, and bone resorption, and
therefore reducing the lifespan of the implant. Porous titanium is thus a suitable candidate as implant material due to its
ability to be manufactured to a specific Young’s modulus—typically that of bone. Porous titanium has the unique advantage
of allowing bone tissue ingrowth into the open space of the implants, thereby accelerating the osseointegration process.
The human body as well as the oral cavity is a highly complex environment in which the simultaneous interaction between
wear and corrosion, namely tribocorrosion, takes place. Thus, understanding these interactions is of great interest in order
to characterize the degradation mechanisms of porous titanium materials used as implants. This paper reviews the state-of-
the-art of porous titanium as a viable biomedical implant material. A significant part of this paper is focused on how porous
titanium is manufactured and how its parameters are controlled. The following sections focus on the corrosion, wear, and
tribocorrosion aspects of porous titanium implant materials. Finally, this review also determines the current limitations in
the field and provides future directions in this field.
Keywords Implant· Porous titanium· Corrosion· Wear· Tribocorrosion
1 Introduction
In recent years, titanium and its alloys have become increas-
ingly important and widely used in the dental and orthopedic
fields due to its high yield strength, good ductility, excellent
corrosion resistance, and superior biocompatibility com-
pared to other materials [1–3]. Musculoskeletal disorders
are one of the most significant health problems facing the
world today, with an estimated cost $254billion to soci-
ety each year, and has been increasing over the past decade
[4, 5]. Due to improvements in surgical techniques and the
development in more intelligent assistive technologies, there
has been a significant increase in the demand for prostheses,
orthopedic implants, and dental implants. Examples of hip
and knee biomedical implants are shown in Fig.1. Over
the past few decades, dental implants have come to be a
significant part of rehabilitation in oral cavity due to tooth
loss or disease. Further, it has been predicted that over one
million implants will be used per year [6]. In the field of
dentistry, survival rates of dental implants exceeded 94% in
the first 10years, indicating their relative success [7]. How-
ever, it has been seen that every fifth dental implant placed
develops peri-implantitis in the initial stages of placement
[1, 4–6]. The proportion of peri-implant mucositis ranged
from 19 to 65% and peri-implantitis ranged from 1 to 47%,
respectively [8, 9]. This shows that there is significant risk of
acquiring these conditions, especially earlier in the implanta-
tion stage. Figure2 shows the various causes of failure for
biomedical implants and when a replacement or revision sur-
gery is needed. The two most important aspects to consider
when choosing implant materials are the relative biocompat-
ibility and its corrosion resistance in the body. Titanium has
been a promising material for biological implants due to its
superior biocompatibility and high corrosion resistance in
the body. A major issue facing the use of titanium implants,
however, is the significant difference between the Young’s
modulus of titanium (110GPa) and bone (10–30GPa) [5–7].
* Pradeep L. Menezes
pmenezes@unr.edu
1 Department ofMechanical Engineering, University
ofNevada Reno, Reno, NV89557, USA
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
... One of the main causes of failures of orthopedic implants is the mechanical mismatch between the bone and the implant [2][3][4]. This difference leads to stress shielding, causing bone resorption, [5] and, in some cases, aseptic loosening and implant failure. ...
... In this context, porous materials have attracted attention in the last years, as they present lower stiffness when compared to solid bulk materials, which can help avoid stress shielding [4,7]. Porous metallic materials can be manufactured by diverse methods, such as powder sintering, gas expansion, investment casting, and, more recently, additive manufacturing [3,8]. Among them, additive manufacturing has as its main advantage the ability to produce architected cellular materials such as lattice structures, which are open porosity non-stochastic solids formed by unit cells [9][10][11][12]. ...
... However, lattice structures have a high area-per-volume ratio [18], and the possible consequences of this feature as part of an implant in the body's environment have not been completely understood. The human body is a dynamic and complex environment [3], and an orthopedic implant material is commonly subjected to various aggressive conditions, such as corrosion, wear, fatigue, and high mechanical loadings. These aggressive conditions can lead to implant failure [2,19]. ...
Effect of designed pore size on electrochemical, wear, and tribocorrosion behavior of additively manufactured Ti-6Al-4V lattice structures
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The advent of additive manufacturing has been a disruptive technology in various fields, including medicine. One of the main causes of orthopedic implant failure is the mismatch between the implant material and the bone, causing bone resorption and aseptic loosening. In this regard, the use of additively manufactured lattice structures as orthopedic implant material has several advantages, such as producing a material with an adequate stiffness match with bone. Nevertheless, its behavior in service is not fully understood: the human body is a complex environment, and an orthopedic implant material is subjected to corrosion, wear, and tribocorrosion. In this work, Ti-6Al-4V solid and lattice structured samples were designed with pore sizes of 500, 700, and 900 µm and produced by PBF-EB. Microstructural and geometrical characterization was made on produced samples. The effect of pore sizes was analyzed under corrosion, wear, and tribocorrosion conditions, and compared with solid bulk samples. During corrosion tests, porous samples presented pitting attacks at high potentials, as the solid samples did not. The porous and solid samples presented similar behaviors under wear and tribocorrosion, with abrasive and adhesive wear as the predominant mechanism, and no statistical difference in the specific wear rates was found.
View
... In those processes, the compression pressure is a key parameter. A high compaction pressure leads to isolated pores, as an example [19]. ...
... First, MAO allows adhesion, proliferation, and differentiation of the cells [37]. The hydrophobia of the surface decreases which increases the quantity of 60 reached for 22% of porosity [19] 200 MPa (Yield stress) [19] High temperature and pressure [19] Porosity morphology dependent on Ti powder and wide diversity [19] Complex device [19] Freeze casting 45-63% [3] Simple and look like trabecular bone [3] 3D printing 40-75% [9] 100-1000 [9] Personalized, able to mimic human pores oriented strut to enhance fatigue toughness [3,9,18,21] Very expensive and not possible to create closed cell [3,9,18,21] Space-holder Dependent on the space-holder Higher porosity and more control over it [19] Collapse risk if removed before sintering [19] Fig. 5 Surface modification purpose [4] Content courtesy of Springer Nature, terms of use apply. Rights reserved. ...
... First, MAO allows adhesion, proliferation, and differentiation of the cells [37]. The hydrophobia of the surface decreases which increases the quantity of 60 reached for 22% of porosity [19] 200 MPa (Yield stress) [19] High temperature and pressure [19] Porosity morphology dependent on Ti powder and wide diversity [19] Complex device [19] Freeze casting 45-63% [3] Simple and look like trabecular bone [3] 3D printing 40-75% [9] 100-1000 [9] Personalized, able to mimic human pores oriented strut to enhance fatigue toughness [3,9,18,21] Very expensive and not possible to create closed cell [3,9,18,21] Space-holder Dependent on the space-holder Higher porosity and more control over it [19] Collapse risk if removed before sintering [19] Fig. 5 Surface modification purpose [4] Content courtesy of Springer Nature, terms of use apply. Rights reserved. ...
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The porous structure needs to be interconnected (raw diameter of 300 µm) to promote vascularization. In order to promote some soft tissue ingrowth, roughness has to reach some right order of magnitude, i.e., between 1 and 10 µm. The stress/strain relation of the bone should not be affected by the scaffold. Even if bulk titanium is widely used in the biomedical field, it will not be a good candidate for such an application. The bulk material’s Young’s modulus is too high and the surface is bio-inert. Usually used in the aeronautic field, the porous form can be a good alternative: the foam’s Young’s modulus being much lower than bulk titanium’s one. This could help avoid stress shielding. The foam’s interconnected pores are also adapted to the bone’s ingrowth and will give better mechanical anchors to the implant. This article gives an overview of the results of titanium foam on the biomedical field, especially on 3 different topics: 1—the different manufacturing processes and the properties of the resulting foam; 2—the surface treatments available and their advantages and drawbacks; 3—the tribocorrosion behavior of the foam and the different parameters influencing the results. The need to control the porosity and the evolution of the mechanical properties of the bones depending on the gender and age of the patient are in favor of a tailor-made foam. Additive manufacturing may be a solution to those issues.
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... Titanium and titanium alloys are frequently utilized in biomedical implants due to their biocompatibility, strong mechanical qualities, and corrosion resistance (Geetha et al., 2009;Singh et al., 2013;Liu et al., 2017;Takizawa et al., 2018;Zhang and Chen, 2019;Chen L. Y. et al., 2020). However, because the elastic modulus of metal is substantially larger than that of bone, this results in a "stress shielding" effect that prevents the necessary stress from reaching the neighboring bone matrix, which eventually causes local osteoclast production and implant loss (Engh et al., 2003;Niinomi and Nakai, 2011;Manoj et al., 2018;Raffa et al., 2021). Bone is made of cancellous and cortical components. ...
... Bone density gradually increases from the inner cancellous bone to the outer cortical bone, revealing uneven and porous structure (Hadjidakis and Androulakis, 2006;Currey, 2011;Chen H. et al., 2020). By altering the size and structure of pores in implants, bone-like mechanical characteristics can be achieved (Engh et al., 2003;Niinomi and Nakai, 2011;Manoj et al., 2018;Raffa et al., 2021). In addition to assisting cell attachment, growth, division and differentiation, biocompatible metal implants should also facilitate the movement of nutrients and metabolic wastes (Ryan et al., 2008;Koolen et al., 2020;Lv et al., 2021;Rana et al., 2021). ...
Porous construction and surface modification of titanium-based materials for osteogenesis: A review
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Titanium and titanium alloy implants are essential for bone tissue regeneration engineering. The current trend is toward the manufacture of implants from materials that mimic the structure, composition and elasticity of bones. Titanium and titanium alloy implants, the most common materials for implants, can be used as a bone conduction material but cannot promote osteogenesis. In clinical practice, there is a high demand for implant surfaces that stimulate bone formation and accelerate bone binding, thus shortening the implantation-to-loading time and enhancing implantation success. To avoid stress shielding, the elastic modulus of porous titanium and titanium alloy implants must match that of bone. Micro-arc oxidation technology has been utilized to increase the surface activity and build a somewhat hard coating on porous titanium and titanium alloy implants. More recently, a growing number of researchers have combined micro-arc oxidation with hydrothermal, ultrasonic, and laser treatments, coatings that inhibit bacterial growth, and acid etching with sand blasting methods to improve bonding to bone. This paper summarizes the reaction at the interface between bone and implant material, the porous design principle of scaffold material, MAO technology and the combination of MAO with other technologies in the field of porous titanium and titanium alloys to encourage their application in the development of medical implants.
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... [15][16][17] In addition, some metal chips produced by abrasion may cause adverse effects, such as cell damage, inammation, allergic reactions, and rash. [18][19][20] The passive lm of titanium alloys can be effectively regenerated to achieve a passivation state aer the surface is mechanically damaged. 21,22 As a result, rapid passivation can prevent the corrosion dissolution of and release of Al and V elements from titanium alloys. ...
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Tribocorrosion is one of the most common forms of failure of biomedical titanium alloys. As the passive film of titanium alloys is highly dependent on oxygen conditions, the passivation behavior and the microstructure of the passive film of Ti-6Al-4V under tribocorrosion in 1 M HCl with a low dissolved oxygen concentration (DOC) were studied by means of electron probe microanalysis (EPMA), Ar-ion etched X-ray photoelectron spectroscopy (XPS), focused ion beam (FIB) milling and high resolution transmission electron microscopy (HRTEM). The results showed that the protective ability of the regenerated passive film decreased sharply under low DOC. Al and V ions dissolved in excess, and a large number of oxygen atoms entered the matrix, leading to internal oxidation. Structural characterization indicated that Ti atoms occupied more metal lattice points in the regenerated passive film and that the high dislocation density in the deformed layer caused by wear facilitated the diffusion of Al and V. Finally, the first-principles calculation showed that Al had the minimum vacancy formation energy.
View
... In this study, the chemical environment of the anodic site in crevice corrosion was simulated, not the geometrical environment. Mechanically assisted crevice corrosion (MACC) has been reported especially for the taper region in artificial hip joints and is the combination of corrosion and mechanical stress or micromotions [18] while tribocorrosion is the combination of wear and corrosion resulting from the mechanical action on the surface due to the friction between two surfaces in a corrosive environment [19] . ...
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Ti6Al4V has been used widely as a biomedical alloy and is increasingly manufactured by additive manufacturing due to customized shapes. As implant material, it is frequently exposed to both friction and corrosive environments. This study investigates the effect of the fabrication process (laser powder bed fusion and forging) on the tribocorrosion behavior of Ti6Al4V in various environments including diluted hydrochloric acid to simulate the acidic environment in a crevice (HCl), phosphate-buffered saline (pH 7.3) with 10 g/L bovine serum albumin (PBS+BSA), and PBS+BSA with 30 mM H2O2. While the presence of BSA hindered the repassivation (reforming of the protective passive surface oxide), the presence of H2O2 accelerated it. HCl resulted in a localized tribocorrosion process. The highest plastic deformation rate was found in the PBS+BSA solution followed by HCl and PBS+BSA+H2O2. In addition, AM parts presented a higher microhardness and smaller grain sizes compared to forged materials. There was no influence of the manufacturing process on the coefficient of friction (COF) in HCl and PBS+BSA solutions, however, a significantly higher COF was found for forged samples in PBS+BSA+H2O2 than AM samples. Tribocorrosion was more extensive for forged than AM Ti6Al4V in all solutions.
View
... For this reason, researchers focus on developing a test method with more than one parameter such as tribo-corrosion, fatigue-corrosion mechanisms. [1][2][3] To evaluate the mechanical, esthetic, and chemical effects of test parameters on biomaterials, ...
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Titanium alloys have emerged as the most successful metallic material to ever be applied in the field of biomedical engineering. This comprehensive review covers the history of titanium in medicine, the properties of titanium and its alloys, the production technologies used to produce biomedical implants, and the most common uses for titanium and its alloys, ranging from orthopedic implants to dental prosthetics and cardiovascular devices. At the core of this success lies the combination of machinability, mechanical strength, biocompatibility, and corrosion resistance. This unique combination of useful traits has positioned titanium alloys as an indispensable material for biomedical engineering applications, enabling safer, more durable, and more efficient treatments for patients affected by various kinds of pathologies. This review takes an in-depth journey into the inherent properties that define titanium alloys and which of them are advantageous for biomedical use. It explores their production techniques and the fabrication methodologies that are utilized to machine them into their final shape. The biomedical applications of titanium alloys are then categorized and described in detail, focusing on which specific advantages titanium alloys are present when compared to other materials. This review not only captures the current state of the art, but also explores the future possibilities and limitations of titanium alloys applied in the biomedical field.
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Porous Titanium Alloy for Prosthesis Attachment
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Description The symposium on Titanium Alloys in Surgical Implants was held in Phoenix, Ariz., on 11-12 May 1981. Sponsoring the event were ASTM Committee F04 on Medical and Surgical Materials and Devices and ASTM Committee B10 on Reactive and Refractory Metals and Alloys. The symposium chairmen were Hugh A. Luckey, 3M Orthopedic Products, and Fred Kubli, Jr., RMI Company, both of whom also served as editors of this publication.
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In this study, Ti-15Zr-xMo (5, 10, 15, and 20 wt%) alloys were submitted to solution and aging treatments and their effects evaluated in terms of phase composition and selected mechanical properties (Vickers microhardness and Young's modulus) for use as biomedical implants. The solution treatment was performed at 1123 K for 2 h, while aging treatments were carried out at 698 K for 4, 8, and 12 h, followed by water quenching. Phase composition and microstructure were dependent of the heat treatments, with Ti-15Zr-5Mo (α + β type) and Ti-15Zr-10Mo (metastable β type) alloys exhibiting intense α phase precipitation. The α-phase precipitates were related to α″ → α and β → α phase decompositions. The Ti-15Zr-10Mo alloy exhibited an intermediary isothermal ω-phase precipitation after aging for 4 h. Vickers microhardness and Young's modulus values changed gradually with the amount of α phase. Aged Ti-15Zr-15Mo and Ti-15Zr-20Mo alloys presented better combinations of hardness and Young's modulus than CP-Ti and Ti-64 ELI for biomedical applications.
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Is Metal Particle Release Associated with Peri-implant Bone Destruction? An Emerging Concept
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Peri-implant diseases affecting the surrounding structures of endosseous dental implants include peri-implant mucositis and peri-implantitis. The prevalence of peri-implantitis ranges between 15% and 20% after 10 y, highlighting the major challenge in clinical practice in the rehabilitation of dental implant patients. The widespread nature of peri-implant bone loss poses difficulties in the management of biological complications affecting the long-term success of osseointegrated implant reconstructions. Metal and titanium particles have been detected in peri-implant supporting tissues. However, it remains unclear what mechanisms could be responsible for the elicitation of particle and ion release and whether these released implant-associated materials have a local and/or systemic impact on the peri-implant soft and hard tissues. Metal particle release as a potential etiologic factor has been intensively studied in the field of orthopedics and is known to provoke aseptic loosening around arthroplasties and is associated with implant failures. In dental medicine, emerging information about metal/titanium particle release suggests that the potential impact of biomaterials at the abutment or bone interfaces may have an influence on the pathogenesis of peri-implant bone loss. This mini-review highlights current evidence of metal particle release around dental implants and future areas for research.
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Corrosion and surface modification on biocompatible metals: A review
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Corrosion prevention in biomaterials has become crucial particularly to overcome inflammation and allergic reactions caused by the biomaterials' implants towards the human body. When these metal implants contacted with fluidic environments such as bloodstream and tissue of the body, most of them became mutually highly antagonistic and subsequently promotes corrosion. Biocompatible implants are typically made up of metallic, ceramic, composite and polymers. The present paper specifically focuses on biocompatible metals which favorably used as implants such as 316L stainless steel, cobalt-chromium-molybdenum, pure titanium and titanium-based alloys. This article also takes a close look at the effect of corrosion towards the implant and human body and the mechanism to improve it. Due to this corrosion delinquent, several surface modification techniques have been used to improve the corrosion behavior of biocompatible metals such as deposition of the coating, development of passivation oxide layer and ion beam surface modification. Apart from that, surface texturing methods such as plasma spraying, chemical etching, blasting, electropolishing, and laser treatment which used to improve corrosion behavior are also discussed in detail. Introduction of surface modifications to biocompatible metals is considered as a “best solution” so far to enhanced corrosion resistance performance; besides achieving superior biocompatibility and promoting osseointegration of biocompatible metals and alloys.
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Degradation mechanisms and future challenges of titanium and its alloys for dental implant applications in oral environment
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Objective: For many decades the failure of titanium implants due to corrosion and wear were approached individually and their synergic effect was not considered. In recent past, developments and understanding of the tribocorrosion aspects have thrown deeper understanding on the failure of implants and this has been reviewed in this article extensively. Methods: Medline, google scholar and Embase search was conducted to identify studies published between 1993 and 2016 which were related to the analysis of degradation mechanism which the dental implants undergo after implantation. Results: In-vitro tests has been extensively carried out to evaluate the tribocorrosion behavior of titanium based dental implants. However, there is still a lack of knowledge about the tangible behavior of materials under in-vivo condition, because the in-vitro experiments are conducted using different testing protocols and conditions (solutions, pH, time, equipment, and testing parameters). Hence, there is an urgent need to perform round-robin test in different laboratories which will help to overcome the gap between in-vitro and in-vivo conditions. Conclusion: Tribocorrosion has been identified as the major degradation mechanisms that result in the failure of dental implants. Hence, it is of utmost importance to improve the service period of dental implants by reducing the tribocorrosion effects through developing new dental implant materials using nobler alloying elements or through modifying the surface of the implants. In order to have a thorough understanding of tribocorrosion behavior and failure mechanisms, round robin test are to be conducted and new protocols/standards are to be developed for the testing of implants.
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Corrosion resistance and cytocompatibility of tantalum-surface-functionalized biomedical ZK60 Mg alloy
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Tantalum (Ta) is introduced to the surface of the ZK60 Mg alloy by reactive magnetron sputtering to enhance the corrosion resistance and cytocompatibility. The film thickness and composition, corrosion behavior, and cytocompatibility are studied by various techniques systematically. The surface layer composed of Ta2O5, Ta suboxide, and Ta increases the corrosion resistance of ZK60 while simultaneously improving cell attachment, spreading, and proliferation in vitro. The enhancement mechanism is proposed and discussed.
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