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Compendium

July/August 2009, Volume 30, Issue 6
Published by AEGIS Communications


GC America Offers Cutting-Edge Nanocomposite

In May 2009 GC America Inc. introduced Kalore, an innovative, light-cured,universal nanocomposite with a new monomer technology licensed exclusively by GC from DuPont.

“Most of the advances in composite technology in the last three decades have been in filler size, type, shape—basically filler composition,” Dr. Robert Lee, Director of Marketing, GC America, explains. “There has been very little focus on the monomer side—until now. DuPont brings a newparadigm shift to dental composite technology along with a proven history of scientific success in acrylic technology.”

Dr. Doug Anton, a Research Fellow at DuPont Central Research in Wilmington, DE, says, “Only about a half a dozen monomers are used by all of the dental manufacturers, and dental composites are distinguished primarily by their fillers. There has not been much of a push in monomers, and we thought it was time to work on that side. We exclusively licensed a family of ‘tunable’ acrylic monomers to GC, so they could pick and choose the right handling characteristics and properly tune the product to develop a truly universal material.”

A combination of a hard segment and soft segments are used in the new monomer family, making it significantly different from the typical polyurethane monomer. Bis-GMA, which has served the industry well for 50 years, is a rigid molecule with short chains and is not as flexible as the long-chain material. Kalore’s unique long-chain monomer with flexible arms provides the basis for very low shrinkage stress, according to Lee. This is ultimately a very important feature because shrinkage stress remains after the composite is cured.

“Stress from shrinkage results in the biggest complaint about light-cured composites—postoperative sensitivity. Each aspect from esthetics to polishability and durability can be followed down to the monomer,” Lee explains. The Kalore monomer, which has the longest chain of any on the market, combined with GC’s patented High Density Radiopaque (HDR) prepolymerized filler, creates a very unique, proprietary interface between the filler and monomer matrix. Less shrinkage stress results in less filler material dropping out of the matrix over time and consequently, sustained gloss and fewer surface stains. According to Anton, another advantage that composites formulated with this monomer family have is that they remain compatible with the other bonding agents dentists are using.

To best serve the subjective needs of dentists and their patients, Kalore is available in three opacities and 26 shades for precision shade matching and blending. Its optimization of the refractive index helps scatter the light so fewer shades are necessary to achieve the chameleon effect. “Esthetics is a very high attribute of Kalore,” says Dr. Wynn Okuda, Past President of the American Academy of Cosmetic Dentistry, who clinically tested the product during development. “It allows better disbursement of light, and the chameleon effect is astonishing. You don’t have to be a ‘super clinician’ to develop beautiful restorations with Kalore. Plus, it’s a universal composite. To me, this is smart technology.”

Okuda has used Kalore in all types of cases, including Class I, Class II, Class IV, Class V, posterior restorations, and veneers. He says Kalore has the best handling characteristics he has ever used. “It’s like spreading butter. It’s not sticky, and it’s not too soft. It’s firm enough to pack in the posterior and flexible enough to be easily spread in the anterior. This is highly sculptable; I feel I have total control. And the polishability is just like a microfill,” Okuda continues. “You can achieve a mirror-like finish with a simple polishing technique—one bur and a couple of polishing wheels.”

DuPont, a global leader in chemistry, had been developing dental monomer technology for several years and was chosen by GC because of DuPont’s recognized excellence in R&D. The contribution of DuPont to the well-established technical strength of GC in the chemistry of dental materials further reinforces GC America’s slogan, “GC America: Enhancing Nature Through Science.”

GC America Inc.
3737 W. 127th Street, Alsip, IL 60803
(800) 323-7063
(800) GCFAXME [fax]
www.gcamerica.com


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Figure 1  No gap on prepolymerized filler interphase. No dropout fillers were observed.

Figure 1