Bioceramic
Rather, bioceramics are closely related to either the body's own materials or are extremely durable metal oxides.
Joint replacements are commonly coated with bioceramic materials to reduce wear and inflammatory response.
[6] Bioceramics are meant[clarification needed] to be used in extracorporeal circulation systems (kidney dialysis, for example) or engineered bioreactors; however, they are most common as implants.
They have the advantage of being inert in the human body, and their hardness and resistance to abrasion makes them useful for bone and tooth replacement.
Some ceramics also have excellent resistance to friction, making them useful as replacement materials for malfunctioning joints.
The material can be used in middle ear ossicles, ocular prostheses, electrical insulation for pacemakers, catheter orifices and in numerous prototypes of implantable systems such as cardiac pumps.
The ceramic-polymer composites are a potential way to fill cavities, replacing amalgams suspected to have toxic effects.
[10][12] Zirconia doped with yttrium oxide has been proposed as a substitute for alumina for osteoarticular prostheses.
Such synthetic bone substitute or scaffold materials are typically porous, which provides an increased surface area that encourages osseointegration, involving cell colonisation and revascularisation.
Other natural materials — generally of animal origin — such as bioglass and other composites feature a combination of mineral-organic composite materials such as HAP, alumina, or titanium dioxide with the biocompatible polymers (polymethylmethacrylate): PMMA, poly(L-lactic) acid: PLLA, poly(ethylene).
[11] Bioceramics' properties of being anticorrosive, biocompatible, and aesthetic make them quite suitable for medical usage.
Carbon is another alternative with similar mechanical properties to bone, and it also features blood compatibility, no tissue reaction, and non-toxicity to cells.
The ceramic particulate reinforcement has led to the choice of more materials for implant applications that include ceramic/ceramic, ceramic/polymer, and ceramic/metal composites.
Ceramic/ceramic composites enjoy superiority due to similarity to bone minerals, exhibiting biocompatibility and a readiness to be shaped.
[10] This can be achieved by the inclusion of grain refining dopants and by imparting defects in the crystalline structure through various physical means.
The prospect of using these relatively low processing temperatures opens up possibilities for mineral organic combinations with improved biological properties through the addition of proteins and biologically active molecules (growth factors, antibiotics, anti-tumor agents, etc.).
However, these materials have poor mechanical properties which can be improved, partially, by combining them with bonding proteins.
[13] Currently, numerous commercial products described as HA are available in various physical forms (e.g. granules, specially designed blocks for specific applications).
Ongoing research involves the chemistry, composition, and micro- and nanostructures of the materials to improve their biocompatibility.
