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May 6, 2009 | DentalProductsReport.com Exclusive
Clinical 360°: Cosmetic/Restorative

Impression materials today
and in the near future

There are plenty of choices—new and old—for dentists looking to make the best possible impressions.

by Dr. Gary Radz

The set-up

“This month Dr. Gary Radz will discuss materials and devices currently used to create a 'master model' of the patient on which the dental ceramist can construct the definitive restorations for the patient. Do the 'new' types of impression materials offer any advantage over those that have been on the market and have a proven ‘track record’?  What about digital impression making…..is there a cost/benefit ratio for these emerging technologies?  Dr. Gary Radz answers these questions in this month's article.” —Dr. Robert Lowe

Today’s marketplace is filled with new dental impression technology ranging from improved traditional material and new hybrid silicone materials to new CAD/CAM systems. Each of these products has its own new “bell and whistle” bringing the promise of the “perfect” impression. How do we make sense of all the information that is out there? What do we need? What are we looking for? Do we really need to make a change and if so at what cost?

What’s out there?
In the world of traditional dental impression materials there have been improvements in providing dentists with many excellent options. Certainly most popular are the polyvinyl silicone (PVS) materials. PVS materials represent a majority of the marketplace today. Many of these materials have been around for years. They’ve also been updated and/or improved over time, including Dentsply Caulk’s  Aquasil Ultra and Kerr Corp.’s  Take 1 Advanced. There have also been some new introductions to the marketplace (Panasil initial contact by Kettenbach) that have dentists and dental labs taking notice, including Kettenbach LP’s Panasil initial contact, which was launched at the Chicago Dental Society’s Midwinter meeting in February.

The PVS materials are popular because they come in multiple viscosities, colors, scents/tastes, and set times. PVS materials are consistently predictable and work well in many different clinical situations. Improvements in flow characteristics and more hydrophilic-like properties have made PVS materials the impression material of choice for many dentists.

Polyether benefits
There still is a significant percentage of the dental market that prefers using polyether (PE) materials. The Impregum line of impression materials from 3M ESPE is one of the most popular and recognizable brands. Dentists who use PE materials are very loyal to them. This is because PE impression materials have been viewed as being more hydrophilic in nature than PVS materials, making PE impression materials ideal for the most challenging of clinical situations where tissue management is difficult and/or compromised. Many dentists also like using PE impression materials for implant impressions and removable prosthetic work.

Recently GC America has introduced EXA’lence impression material to the market with claims of it being a hybrid silicone material thus bringing to the dentists the best of PVS and PE materials. Certainly this is an interesting concept. However, this material is so new that it’s hard to comment on the material, but certainly the idea has merit. This year at the IDS in Cologne, Kettenbach launched Identium®, a vinylsiloxanether® (VSXE®), which is currently only available in select European markets. This technology could be the catalyst for the next wave of chemical impression materials.

Alternatives

Refer to slideshow
for figures

A recent subcategory of the PVS impression materials has been the introduction of “alginate alternatives” (AA). AlgiNot by Kerr, Status Blue by DMG America, PositionPenta by 3M ESPE, and most recently Silginat by Kettenbach LP are all materials available with the intention of using these materials instead of alginate.

There are numerous benefits of this concept. AA materials though more expensive than alginate, are less expensive than conventional PVS materials. AA materials all have set times that are similar to alginate. Additionally, they have a significant advantage over alginate in that they can be poured repeatedly and they have long-term stability. These characteristics make them ideal materials for impression for study models and as the pre-operative matrices for provisional restorations.

Additionally, these materials are accurate enough for using as the impression material for sports mouthguards, occlusal splints, and opposing models. The last significant advantage of using AA materials is the time savings. With the AA materials the assistant takes the dental impression, quickly disinfects it and encloses it in a “ZipLoc” bag. The impression can be poured whenever time permits, or the impression can be poured at the dental laboratory. There is no messy cleaning of metal trays, or the expense of using disposable trays (Fig. 1).  

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