What are Ceramics?

Ceramics are hard materials that are inorganic and nonmetallic. They are materials which are formed by the action of heat.

The word ceramic comes from the Greek keramikos. Examples of ceramics are clay, glass, cement, and porcelain.

Ceramics are used in many structures including bricks, tiles, china dishes, and pottery. Ceramic materials can also be used for medical and scientific purposes.

Ceramics have a high resistance to wear and corrosion. They tend to be more heat resistant than most metals. They are, however, very hard and brittle.

Ceramic on ceramic arthroplasties are another attempt to use alternative bearing surfaces to reduce wear and debris.

Ceramics have been used for more than 30 years, but recent designs have become more popular. Both ceramic on ceramic and ceramic on polyethylene combinations have been tried.

The two most common types of ceramic that are used in hip replacements are alumina and zirconia. These materials are hard and inert. They have good wettability and the opposing surfaces are well lubricated against one another.

They are resistant to wear and to corrosion and are not known to cause any local reaction. In contrast to metal, there is no ion release which could cause long-term effects in other organs of the body.

Although ceramic materials are very hard and firm, they are also very brittle. There has been a small incidence of component fracture when ceramics are used.

In addition, ceramic on ceramic bearings are some-times noted to have a clicking or squeaking effect. This occurs in a small number of ceramic replacements. The cause is not clear.

It is felt that careful placement of the components to avoid scratching and impingement will help prevent a ceramic hip from squeaking.

Further research and long-term studies are required to determine the relative risks and benefits of alternative bearings such as ceramics and metal on metal.

The goal is to provide bearing surfaces that will be durable and not have any long-term local or systemic effects.