Bioceramics and bioglasses are ceramic materials that are biocompatible[1]. Bioceramics are an important subset of biomaterials[2][3]. Bioceramics range in biocompatibility from the ceramic oxides, which are inert in the body, to the other extreme of resorbable materials, which are eventually replaced by the materials which they were used to repair. Bioceramics are used in many types of medical procedures. A primary medical procedures where they are used is implants[4]. This article is primarily concerned with rigid materials commonly used as 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.
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Prior to 1925 the materials used in implant surgery were primarily relatively pure metals, however these are not considered to be ceramics and are therefore outside the scope of this article. The success of these materials was surprising considering the relatively primitive surgical techniques. The 1930's marked the beginning of the era of better surgical techniques and also the first use of alloys such as Vitallium.
In 1969 L. L. Hench and others discovered that various kinds of glasses and ceramics could bond to living bone[5][6] Hench was inspired with the idea on his way to a conference on materials. He was seated next to a colonel who had just returned from the Vietnam War. The colonel shared that after an injury the bodies of soldiers would oftentimes reject the implant. Hench was intrigued and began to investigate materials that would be biocompatible. The final product was a new material which he called Bioglass. This work inspired a new field called bioceramics[7]. With the discovery of bioglass interest in bioceramics grew rapidly.
On April 26, 1988 the first international symposium on bioceramics was held in Kyoto Japan
Ceramics are now commonly used in the medical fields as dental, and bone implants.[8][9] Artificial teeth, and bones are relatively commonplace. Surgical cermets are used regularly. Joint replacements are commonly coated with bioceramic materials to reduce wear and inflammatory response. Other examples of medical uses for bioceramics are in pacemakers, kidney dialysis machines, and respirators.[10] The global demand on medical ceramics / ceramic components was about US$9.8 billion in 2010. It is forecast to have an annual growth of 6-7% in the following years, and the world market value will increase to US$15.3 billion by 2015 and reach US$18.5 billion by 2018. [11]
One proposed use for bioceramics is the treatment of cancer. Two methods of treatment have been proposed; treatment through hyperthermia, and radiotherapy. Hyperthermia treatment involves implanting a bioceramic material that contains a ferrite or other magnetic material. The area is then exposed to 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.[12].
Other trends include engineering the materials for specific tasks. Ongoing research involves the chemistry, composition, and micro and nanostructures of the materials to improve their biocompatibility[13][14][15].
Bioceramic materials are commonly subdivided by their bioactivity. Bioinert materials are non-toxic, non-inflammation causing. These materials must be long lasting, structural failure resistant, and corrosion resistant. Bioceramics additionally must have a low Young’s modulus to help prevent cracking of the material.