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Scaffold-Based Tissue Engineering for Craniofacial Deformities
Published in Atul Babbar, Ranvijay Kumar, Vikas Dhawan, Nishant Ranjan, Ankit Sharma, Additive Manufacturing of Polymers for Tissue Engineering, 2023
Jasmine Nindra, Mona Prabhakar
Bioceramics mimic the bone tissue, as they provide higher osteoblastic adherence and proliferation (Ducheyne & Qiu, 1999). The mechanical strength of ceramics is superior than polymers; however, in terms of tensile and torsion strength, they are still inferior to natural bone. They show both osteoconductive and osteoinductive properties. Common types of calcium phosphate ceramics used are tricalcium phosphate, hydroxyapatite, and their combinations as biphasic and amorphous calcium phosphates (Dorozhkin & Epple, 2002). Studies have shown that doping tricalcium phosphate scaffolds with ZnO (0.25%) and SiO2 (0.5%) bring about a 2.5-fold increase in compressive strength and 92% increase in cell viability (Fielding et al., 2012).
Applications of Thin Films in Metallic Implants
Published in Sam Zhang, Materials for Devices, 2023
Katayoon Kalantari, Bahram Saleh, Thomas J. Webster
One of the main components of teeth and bone in vertebrates is calcium phosphate salts. Among calcium phosphate salts, hydroxyapatite (HAp) with the chemical formula of [Ca10(PO4)6(OH)2] is the most stable crystalline phase in body fluids, and is similar to the mineral part of bone [96]. It has been well known that HAp has the ability to promote bone ingrowth without any inflammation or toxicity and can be used as a dental material, middle ear and bioactive coating on metallic osseous implants [97–99]. A HAp coating can be deposited on the surface of metal alloys to support the osseointegration of implants with the surrounding bone [100]. Some mechanical properties, like load-bearing ability, can be maintained by using a HAp coating and they also show good biocompatibility with bone [101]. Some disadvantages such as poor thickness uniformity, poor adhesion to an underlying substrate, high porosity, impurity in phases, and limited crystallinity are common in HAp coatings. Nevertheless, low coating adhesion has been known as the main disadvantage in using HAp as an implant commercially; thus, as a general requirement, the strength of bonding between a ceramic coating and metallic substrate should be improved, regardless of the method utilized [100].
Thin Films for Biomedical Applications
Published in Fredrick Madaraka Mwema, Tien-Chien Jen, Lin Zhu, Thin Film Coatings, 2022
Fredrick Madaraka Mwema, Tien-Chien Jen, Lin Zhu
Bioactive ceramics include calcium phosphate and glass-based ceramics. Some of the calcium phosphates used as biomaterials include tetracalcium phosphate (TTCP), hydroxyapatite (HA), tricalcium phosphate (TCP), octacalcium phosphate (OCP), brushite, tetracalcium dihydrogen phosphate (TDHP), etc. The most commonly used bioactive ceramic for bone replacement is HA because of its chemical similarity to bone and teeth. It has a chemical formula of Ca10(PO4)6(OH)2 and has a Ca/P molar ratio of 1.67. These calcium phosphates are used in bone and teeth replacement and tend to dissolve during bone regeneration. Bioactive glass® is another ceramic biomaterial that has close structural similarity to the bone and can bond directly with tissues. The bioactive glasses have a higher rate of reactivity and bonding with the tissues although their applications are limited by the low fracture toughness.
Electrochemical deposition of a biofunctionalised silver and strontium substituted hydroxyapatite nanocomposite coating on a β-type titanium alloy
Published in Transactions of the IMF, 2023
Azadeh Esmaeil Nejad, Hanieh Nojehdehian, Amir Pasha, Negin Nikmanesh
Calcium phosphates are frequently used to add biofunctionality to implant surfaces due to their properties, such as bioactivity, osteoconductivity, biocompatibility, non-immunogenicity, and chemical similarity to the mineral apatite of bone tissue.5 As found in most of the previous studies, implant clinical success rate will improve as implant surface similarities to the surrounding bone structure increase.6 The principal bone tissue mineral component is rod-shaped or needle-like, nanometre-sized hydroxyapatite(nano-HAp); its chemical composition varying from the stoichiometric HAp(Ca10(PO4)6(OH)2) and substitution of Ca by several ions – Na, Mg, Zn, etc. – in its structure could explain this discrepancy.7,8 Ionic substitutions have been suggested as a method to add further biological functions, i.e. antibacterial efficiency, of HAp. From Huang et al.’s study in 2017, strontium (Sr) and silver (Ag) are appropriate dopants for adding osteoinductivity and an antibacterial property to it.9 Ag has long term antimicrobial efficacy from a single dose application and a low chance of microbial resistance in comparison with conventional antibiotics.10,11 In the same way, Sr as a secondary dopant is of paramount interest due to Sr’s biological role in enhancing osteoblast activity and inhibiting osteoclast activity.12
Sintering behavior and mechanical properties of calcium phosphate–alumina composite porous scaffolds
Published in Advanced Composite Materials, 2023
Calcium phosphate ceramics, such as hydroxyapatite (HA, Ca10(PO4)6(OH)2) and tricalcium phosphate (TCP, Ca3(PO4)2), which are composed of phosphate and calcium ions, are components of living bone [1,2]. These ceramics can gradually transform into living tissues and have attracted considerable attention because of their application as artificial bones and highly biocompatible biomaterials. The biodegradation rate varies depending on the crystalline structure and chemical composition and increases in the order of HA, β-TCP, and α-TCP, with HA classified as almost non-biodegradable. In 1977, Akao et al. [3] reported that HA can bond directly with living bones. As HA can exist stably for a long period while gradually integrating with living bones in vivo, HA scaffolds have been the subject of intense research [4].
Microhardness and microstructural properties of a mixture of hydroxyapatite and β-tricalcium phosphate
Published in Journal of Asian Ceramic Societies, 2023
Se Woong Lee, Yurian Kim, Hyung Tay Rho, Sang-il Kim
Life expectancy for humans has been increasing, and bone tissue engineering using biomaterials for bone tissue defects is gaining traction. Currently, calcium phosphates have attracted attention for bone grafting applications owing to their high osteoconductivity [1–3]. One of the most important advantages of calcium phosphates is their similarity to the mineral phase of the human bone. Calcium phosphates such as hydroxyapatite (HA), α-tricalcium phosphate (α-TCP), biphasic calcium phosphate (BCP), and β-tricalcium phosphate (β-TCP) are widely used as bone-grafting materials for bone regeneration in dental and orthopedic applications. A mixture of HA and β-TCP has been widely used in dental applications, like a mixture of calcium silicates (dicalcium silicate and tricalcium silicate) [4].