Going to the dentist is like playing in a rare metals toybox!

May 4, 2011 (Ian London, Editor www.RMBApps.com) — Modern dentistry can be quite the marvel, especially with respect to observing rare metal material science at work. These metals enable the latest diagnostic technologies, as well as faster, smaller, and quieter tools.  In a modern dental office, rare earths and rare metals are also found in LED lamps, flatscreen display units and film-less X-ray techniques.  Material science is also contributing to significant advances in prosthetics, be they crowns, veneers or implants.

Here are just two simple examples of rare metals at work — lithium disilicate and zirconia in dental restoration materials. These restorative materials are applied to restore the function and integrity of missing tooth structure.

Thus far, gold, amalgam*, resin-reinforced glass, and porcelain are amongst the most popular materials used for these purposes. [*dental amalgams are composed of 43% to 54% by weight of mercury, with the remaining powder made up of mainly silver (~20-35%) and some tin, copper (~10%), and zinc (~2%].

Lithium disilicate glass-ceramic provides highly aesthetic results and, compared to other glass-ceramics, demonstrates a strength that is 2.5 to 3 times higher. It is available in ingots for pressing, and in blocks that can be milled with several different CAD/CAM milling machines.  Furthermore, it is available in many shades, and thus a highly suitable product for dental veneers. When supported with zirconium oxide, lithium disilicate may also be used for bridge applications.

A monolithic material, lithium disilicate enables less invasive preparations, more aesthetic restorations, easier fabrication techniques, improved laboratory production, improved laboratory economy, standardized laboratory protocols, and facilitates laboratory standards

Before the 1990s, porcelain-fused-to-metal was used to provide strength to a crown or bridge. These restorations are very strong, durable, and resistant to wear, because the combination of porcelain and metal creates a stronger restoration than porcelain used alone. Since the 1990s, however, all-ceramic dentures have been considered an alternative solution to porcelain-fused-to-metal, primarily because of advancements of the material itself. The reliability of porcelain restorations has increased considerably, especially with zircon (or zirconium, or zirconium oxide). Zirconium oxide is a high performance all-ceramic, which offers better stability and usability than conventional all-ceramic (porcelain).

Zirconium-oxide, with its high strength and comparatively higher fracture toughness, can be used in virtually every full ceramic prosthetic solution. Zirconia displays excellent biocompatibility with significant reduction of plaque and bacterial adhesion on surfaces. And with zirconia, dentists seldom find themselves replacing crowns and bridges every few years due to daily wear and tear.

Also, for all-important aesthetics, these materials are available in a range of shades (e.g. white, light, medium, intense) that are guaranteed to be consistent.

There are not a lot of folks who love going to a dentist's office. If you're a rare metals type, with an eye for advances in technology, and the materials that make them possible, you may actually be able to find something that holds your interest. At least until that drill comes out.