17th Science Apéro
Material research for dental implants
| The first speaker was Dr. Christoph Hämmerle, a professor of dentistry at the University of Zurich, who talked about the use of implants in dental practice. | ||||
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The perfect
tooth Implants have created a revolution in dental treatment, because thanks to them it is now possible to completely replace a lost tooth with man-made materials. An implant cannot be distinguished from a natural tooth, either visually or in terms of functional performance. Ten years after insertion into the patients’ mouths, up to 95% of all implants still function properly, although it must be said that a patient’s habits play an important role here. Nicotine, alcohol or drug abuse can dramatically reduce the success rate. |
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Implants, usually made of titanium, are inserted into the jawbone to create an artificial root, to which a man-made tooth is attached. Within a few weeks the implant and bone fuse together, and the surrounding soft tissue grows around the new root. The crown – the visible part of the replacement tooth – is made of ceramic and is screwed onto the new root implant. It demands skill and experience in preparing the new crown so that the darker titanium root is not visible through the ceramic as a shadow, detracting from the cosmetic effect. |
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Ceramic implants The use of ceramic root implants would solve this particular aesthetic problem, although this is not the only reason why for many years there has been interest in non-metallic materials for implants. Some patients are extremely sensitive to the use of metallic compounds in the mouth. The second speaker, Dr. Wolfram Weber of Metoxit AG in Thayngen, Switzerland, was therefore confident that ceramics could offer an alternative to titanium for making implants. He revealed to the audience the results of the latest research into ceramic materials for dentistry. The introduction of zirconium oxide (ZrO2) for orthopedic use in 1995 cleared the way for the use of this material, which with a mechanical strength of 1200MPa is stronger than titanium, in dentistry too. While there are no doubts about the biocompatibility of ceramics, it is essential for the success of the treatment that the root implant fuses together with the jawbone. Research on the surface properties and bone-integration characteristics of ceramic implants is currently underway to optimize this effect. |
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The interaction of cells with materials This was the topic of the last presentation, by Dr. Arie Bruinink of Empa’s MaTisMEd team. The interaction between human cells and the implant material plays a decisive role in the bone growth process. The surface properties of the implant material, i.e. the structure and chemistry of the surface layer, together with the substances which it releases, determine the response of cells in the surrounding tissue. Mechanical loading is another factor which influences cell function. To gain a better understanding of material-cell interactions, research on cell cultures is in progress to determine how particular cells respond to various environments. |
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| For long term observation of cell behavior, the Empa team is using a confocal laser scanning microscope. Images of different focal planes are taken periodically (e.g. every 15 minutes) and combined to create a film clip. This method allows the researchers to determine the location, movement and shape of individual cells, as well as the behavior of a specific cell in response to surface structures. | ||||
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It should as a result be possible in the near future to be able to state with confidence which surface characteristics are important for particular cell types, and which are of less significance.
The next Science Apéro will take place on June 29th 2004
on the topic “Nanotechnology – the opportunities and
risks”
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