Context

Ceramic implants can regenerate broken bones and will help to regrow the bones as well.

Background

• Prior to 1925, the materials used in implant surgery were primarily relatively pure metals.
• The success of ceramic materials was surprising considering the relatively primitive surgical techniques.
• The 1930s marked the beginning of the era of better surgical techniques as well as the first use of alloys such as vitallium.
• Ceramics are now commonly used in the medical fields as dental and bone implants.
• These are surgical cermet, used for Joint replacements are commonly coated with bio-ceramic materials to reduce wear and inflammatory response.
• Other examples of medical uses for bio-ceramics are in pacemakers, kidney dialysis machines, and respirators.

About

• A bone replacement following a fracture, it is often based on a metal part.
• But metal parts are sometimes toxic over time, and will not help the original bone regrow.
• The Tokyo Medical and Dental University (TMDU) research found that, Calcium phosphate ceramicsare in principle an ideal alternative to conventional metals because bone can eventually replace the ceramic and regrow.
• Calcium phosphate ceramics are substitutes for the bone mineral hydroxyapatite.
• The researchers have reported that most of the studied ceramics underwent chemical transformations into particulate or fibrous hydroxyapatite within a few days.

Analysis

What are Bioceramics?

• Bioceramics are typically used as rigid materials in surgical implants, though some bioceramics are flexible.
• The ceramic materials used are not the same as porcelain type ceramic materials. Rather, bioceramics are closely related to either the body's own materials or are extremely durable metal oxides.
• Bioceramics are meant to be used in extracorporeal circulation systems (dialysis for example) or engineered bioreactors; however, they're most common as implants.
• Ceramics show numerous applications as biomaterials due to their physico-chemical properties.
• They have the advantage of being inert in the human body, and their hardness and resistance to abrasion makes them useful for bones and teeth replacement.
• Some ceramics also have excellent resistance to friction, making them useful as replacement materials for malfunctioning joints.
• Properties such as appearance and electrical insulation are also a concern for specific biomedical applications.

How does it work?

• Calcium phosphate-based ceramics constitute the preferred bone substitute material in orthopaedic and maxillofacial applications, as they are similar to the main mineral phase of bone in structure and chemical composition.
• Such synthetic bone substitutes are typically porous, which provides an increased surface area that encourages absorption, involving cell colonisation and revascularisation.
• However, such porous materials generally exhibit lower mechanical strength compared to bone, making highly porous implants very delicate.
• Since the elastic modulus values of ceramic materials are generally higher than that of the surrounding bone tissue, the implant can cause mechanical stresses at the bone interface.

Future prospects

• Bioceramics have been proposed as a possible treatment for cancer.
• Two methods of treatment are hyperthermia and radiotherapy. 
• Hyperthermia treatment involves implanting a bioceramic material that contains a ferrite or other magnetic material. The area is then exposed to an alternating magnetic field, which causes the implant and surrounding area to heat up. Alternatively, the bioceramic materials can be doped with β-emitting materials and implanted into the cancerous area.
• Other trends include engineering bioceramics for specific tasks.
• On-going research involves the chemistry, composition, and micro- and nanostructures of the materials to improve their biocompatibility.