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Biomaterials in Tissue Engineering
Published in Rajesh K. Kesharwani, Raj K. Keservani, Anil K. Sharma, Tissue Engineering, 2022
Blessing Atim Aderibigbe, Shesan John Owonubi
Selected metals such as surgical cobalt–chromium (Co–Cr) alloys, stainless steel (316L), and titanium (Ti) alloys are commonly used metals for fracture fixation and bone remodeling (Prasad et al., 2017). They exhibit long-term stability resulting from their low corrosion, excellent mechanical properties, and friction. Surgical stainless-steel alloys (316L) made with varying amounts of nickel, iron, and chromium have been used in the manufacture of prostheses (Yoo et al., 2008). The low carbon content in surgical stainless steel reduces corrosion and metal allergic reactions (Yoo et al., 2008). However, it is prone to stress corrosion and cracking. Its use is often limited in biomedical application where strength is not required for a prolonged period (Pruitt and Chakravartula, 2012). Stainless steels are less expensive when compared to other alloys. However, some metals lack a biologically active surface that can induce osteointegration or prevent infections resulting in more research which involves the coating of implants. In the selection of coatings for metal implants used for bone replacement, factors such as biocompatibility, the capability to induce osteoblasts, good mechanical stability, and antimicrobial activity must be considered (Godbole et al., 2016; Kiel et al., 2008). Metal implants are used for artificial hip joints, bone plates, spinal fixation devices, and artificial dental roots. The mechanical biocompatibility of metals used for implants is measured by Young’s modulus, which describes the response of a material to stress and strain (Niinomi and Nakai, 2014). Metals with Young’s modulus, equal to that of the bone, are ideal for metallic implants, thereby reducing the stress shielding effect (Niinomi and Nakai, 2014).
Prediction of abrasive wears behavior of dental composites using an artificial neural network
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2023
Abhijeet Shivaji Suryawanshi, Niranjana Behera
The tribological behavior of four different dental composite materials immersed in the chewable tobacco solution was carried out using a pin-on-disc tribometer (ASTM G99-04) (Nuraliza et al. 2016). The cylindrical pins made of these dental composite materials were prepared by utilizing an elastomer mold. A layer of a thickness of 1 to 3 mm is condensed in the mold. An LED curing light is used for condensing and polymerizing each layer in the mold. The curing time was set according to the manufacturing catalogue. After that, the samples were submerged in distilled water for seven days. The disc was made of stainless steel 316 L grade, which is also known as “Surgical Stainless Steel” and is mostly used for biomedical equipment (Yildirim Bicer et al. 2015). The required surface roughness of 0.8 µm for both the pin and disc specimens was achieved by using 600 grit sandpaper (Suryawanshi and Behera, 2020). To recreate the real oral environment, various test parameters are taken into consideration for the experimentation, such as track width of 50 mm, disc speed of 100 rpm, and test duration of 10 minutes (Callaghan et al. 2006).
Prediction of wear of dental composite materials using machine learning algorithms
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2023
Abhijeet Suryawanshi, Niranjana Behera
A pin-on-disc tribometer (ASTM G99-04) was used to measure the tribological properties of four different dental composite materials immersed in the chewable tobacco solution (Nuraliza et al. 2016). These dental composite materials were used to create the cylindrical pins, which were then prepared using an elastomer mold. In the mold, a layer is condensed that ranges in thickness from 1 to 3 mm. Each layer in the mold is condensed and polymerized using an LED curing light. Curing time was decided based on the data given in the manufacturing catalog. Following this, the samples were then immersed in distilled water for seven days. The disc was constructed from stainless steel of grade 316 L, sometimes referred to as ‘Surgical Stainless Steel’, and is typically seen in biomedical equipment. Sandpaper with a 600-grit rating was used to produce the required surface roughness of 0.8 m for both the pin and disc specimens (Suryawanshi and Behera 2020a). Different test settings, including track width of 50 mm, disc speed of 100 rpm, and test time of 10 min, are taken into consideration for the experiment to simulate the real oral environment (Callaghan et al. 2006).
Rheological study of the developed medium and its correlation with surface roughness during abrasive flow finishing of micro-slots
Published in Machining Science and Technology, 2020
Sachin Singh, Mamilla Ravi Sankar
As discovered from the literature survey, very few authors conducted a rheological study of the developed medium for finishing of micro-features. There is a vast unexplored area in the development of the AFF medium, which is not only economical, but can also help in achieving nanosurface roughness on the micro-feature of the component. Micro-featured components are widely found in medical industry. The surface roughness on such components plays a vital role in deciding their functional performance, one such critical component is drug eluting stents (DES). DES have micro-features (micro-slots) for delivering drugs. These micro-slots are commonly micro-machined by thermal-based manufacturing processes (lasers, electric discharge machining (EDM)). Due to the inherent nature of such processes, these generate workpieces with high surface roughness because of the presence of recast layer on their machined surfaces. If DES with micro-slots having high surface roughness are used to deliver the medicine in the patient's body it can cause a change in the flow rate of medicine, and there are chances of medicine retention in the high surface roughness valleys, as well as potential contamination of medicine due to the addition of loosely bonded metal debris. All these can be harmful for patient’s health. Thus, finishing micro-features on the medical components is very important. Micro-dimensions of the component’s features offer great resistance to the medium flow during the finishing process. In the present work, to overcome such challenges, an economical in-house viscoelastic medium with dominant viscous properties is developed. In order to ensure that the developed medium meets the requirement for finishing of micro-features by AFF process, rheological study is carried out. Rheological properties (static and dynamic) of the developed medium are studied by using MCR-101 rheometer. Later, to study the performance of the developed medium, inner walls of micro-slots fabricated on surgical stainless steel (SS 316L) are finished by AFF process. Experiments are performed to study the role of AFF input parameters (extrusion pressure, AFF cycles, abrasive particle size (D) and wt.% of the abrasive particles) on the AFF output response (percentage change in surface roughness (% ΔRa).