Common Use of Ceramics in Dental and Orthopaedic Applications

Ceramics are most commonly used in dental applications as restorative materials for crowns, cements and dentures.

Some ceramics are used in orthopaedic applications such as bone repair, bone augmentation and joint replacement but their use in this field is not as extensive or widespread as metals and polymers because ceramics have poor fracture toughness. This severely limits the use of ceramics in load bearing applications (Davis, 2003).

Ceramics have high hardness and wear resistance, making them suitable for applications such as the articulating surfaces in joints and bone bonding surfaces in implants. Ceramics like alumina and zirconia are more appropriate to use in joint replacements and dentistry whereas hydroxyapatite or calcium phosphate cements are useful for bone bonding applications which is assist with bone growth and implant integration with surrounding natural bone and tissues (http://www.azom.com/article.aspx?ArticleID=108).

Alumina and zirconia ceramics have been widely used in orthopaedic hip replacements for the past 30 years. The advantage of using these was lower wear rates than those observed using polymers and metals. Because of the ionic bonds and chemical stability of ceramics, they are relatively biocompatible and therefore more preferable to use than metals and polymers. Alumina is most commonly used as a femoral head component instead of a metal in a hip prosthesis because this would reduce the polyethylene wear that is generated. Alumina is a desirable biomaterial to use in hard tissue implants because of characteristics like excellent wear resistance, high hardness, bio inert, low abrasion rate and good frictional behaviour. Furthermore, it has excellent surface finish as well as high fatigue streng...

... middle of paper ...

...stainless steel and Co-Cr alloys which results in poor rigidity. Alongside this, titanium is a light material which would make it difficult to see under x-ray imaging (Hanawa, 2009).

Metal alloys and precious metals are also used to make certain aspects of a cochlear implant. The electrode arrays that provide electrical stimulation in order to excite neurons are made out of platinum because they have very high corrosion resistance, good biocompatibility, easier to work with than iridium and have low chemical reactivity. On the other hand, metallic alloys like titanium are used to make the casing for the receiver/stimulator. Titanium is suitable for such an application because it is a light material with high corrosion resistance and rigidity and these properties are essential for the material that is going to be used to make the casing (Stöverl and Lenarz, 2009).