Indonesia is a country with a fairly high elderly population, reaching 25 million people in 2019 and increasing over time. With a highly elderly population, the risk of osteoporosis, osteoarthritis, and other bone diseases also increases. This causes the need for orthopedic implants to be felt even higher. In orthopedic implants, titanium is the most widely used metal material due to its high mechanical properties, good corrosion resistance, and biocompatibility. However, the use of titanium implants for a long time can lead to implant failure due to the large difference in modulus of elasticity between titanium (110 GPa) and bone (4-20 GPa).
One of the developments in the application of titanium as an orthopedic implant that can be done is to form a porous material structure to increase osseointegration (the process of attaching bone to the implant). Development can also be carried out by increasing the properties of bioinert (materials that do not affect or do not interact with body tissues) to become bioactive (interface properties that trigger the formation of bonds between tissues and implant materials). With the presence of bioactive properties on the surface, cell adhesion and new cell growth will be better. This is what prompted Dyah Annur to take up this theme in her dissertation entitled “Development of Porous Titanium Materials Using Powder Metallurgy Methods and Hydroxyapatite/Chitosan Coatings for Orthopedic Implant Applications”.
In this research, Dyah studied the manufacture of porous titanium using the powder metallurgy (PM) method with a partial sintering approach and using a space holder as well as using spark plasma sintering (SPS), arc plasma sintering (APS), and argon sintering. After optimizing the pore formation, the research continued with surface modification with chitosan hydroxyapatite coating. Microstructure characterization was carried out with an optical microscope to determine pore size and porosity as well as phase analysis with an X-Ray diffractometer (XRD) followed by electrochemical testing to determine corrosion resistance and cytotoxicity testing to determine biocompatibility properties.
Based on the pore characteristics produced, the space holder method can produce pores with a larger percentage of porosity and pore sizes that are more suitable for orthopedic implants. Improvement of mechanical properties in terms of reducing the modulus of elasticity can be achieved either by partial sintering or space holder methods. Based on the evaluation of pore formation, the T1-20 1000 specimen, namely porous titanium with 20% by weight of NaCl (34% by volume) has the potential as a porous titanium material for orthopedic implants. Pores have an average size of 282+95 μm with a porosity of 37%.
“The mechanical strength of Ti 20 1000 is quite good (E = 4.9 GPa, Yield Strength is 157 MPa). The properties of corrosion resistance and biocompatibility are also quite good. Furthermore, coating hydroxyapatite chitosan (HA/Kit) by electrophoretic deposition (EPD) with parameters 6V-15 minutes, appeared to improve the biocompatibility properties of porous titanium. Thus, Ti 20 1000 with HA/Kit 6V-15 minutes has the potential to be used as an orthopedic implant,” Dyah said at the end of his dissertation conclusion.
“Congratulations to Dyah Annur for conferring a Doctoral degree. Dyah is the 59th Doctor from the Department of Metallurgy and Materials Engineering and the 481st Doctor of FTUI. Hopefully, Dyah’s research results regarding porous titanium materials can be utilized for the development of porous orthopedic implants in the future. This research will help people who are constrained by osteoporosis, osteoarthritis, and other bone diseases in their daily lives,” said the Dean of FTUI, Prof. Dr. Heri Hermansyah, ST., M.Eng., IPU.
A research dissertation on the development of porous titanium for orthopedic implants succeeded in earning Dyah Annur a doctorate degree on December 22, 2022. The Promotion Session was chaired by Prof. Dr. Ir. Yanuar, M.Eng., M.Sc., with promoter Prof. Dr. -Ing. Ir. Bambang Suharno and co-promoter Sugeng Supriadi, ST., M.S.Eng., Ph.D. While the examiner team consisted of Prof. Dr. Ir. Akhmad Herman Yuwono, M. Phil. Eng.; Dr. Ika Kartika, S.T., M.T.; Dr. Deni Ferdian, ST., M.Sc; Dr. Ir. Myma Ariati Mochtar, M.S.; and Dr. Ir. Donanta Dhaneswara, M.Sc.
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Faculty of Engineering, Universitas Indonesia