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October 2009
Volume 30, Issue 8

Kuraray Adhesives Offer Advanced Technology, Proven Performance

When conducting product research and development, Kuraray scientists have an extremely focused vision. “We try to develop products for rebuilding and reinforcing natural tooth structure so that dentists can use the most conservative procedures and patients enjoy their own teeth their entire life,” says Junichi “Johnny” Ohtsuki, Senior Technical Manager. “Our goal is to manufacture products that improve patients’ quality of life.”

One of the results of this dedication is Kuraray’s well-received, highly effective dental adhesive systems. “Clearfil™ SE Bond has been the top brand of self-etch adhesives globally for over 10 years,” Ohtsuki says. Kuraray is also very proud of its improved sister product to Clearfil SE Bond: the award-winning Clearfil™ Protect Bond, which features FDA-certified antibacterial cavity cleansing and fluoride-releasing technology components.

The chemistry of Clearfil Protect Bond is based on that of the highly regarded Clearfil SE Bond, which contains MDP, an epoch-making adhesive monomer in dentistry. MDP forms extremely strong chemical bonds to calcium and polymerized adhesive resin; the incorporation of MDP provides excellent water resistance. Kuraray’s original self-etching process with MDP promotes penetration of the primer into tooth structure and enhances the dissolving and hybridization of the smear layer and tooth structure. MDP-based Clearfil SE Bond shows high hydrolytic stability in the adhesion interface, contributing to long-term clinical reliability.

In addition, a large body of scientific research has demonstrated the antibacterial effects of Clearfil Protect Bond and its monomer, MDPB, which has a functional group that provides an antibacterial effect. The mechanism of this antibacterial effect is similar to the well-known antibacterial agent CPC in toothpastes and mouth rinses. However, a critical difference between MDPB and CPC is MDPB polymerization after penetrating the tooth structure. MDPB is fixed in the polymer at the adhesion interface and will not leak after the bonding process. “Therefore, Clearfil Protect Bond with MDPB monomer provides a biologically safe antibacterial effect with excellent cavity sealing against microleakage,” Ohtsuki explains.

Kuraray developed a polymer-encapsulated NaF for resin adhesive materials. Ohtsuki says, “In Clearfil Protect Bond, the encapsulated fluorides maintain mechanical strength after releasing the fluoride.”

As a pioneer and leader of dental adhesive technology, Kuraray also has assumed responsibility to promote and disseminate reliable research on dentistry’s cutting-edge issues, including the question of total-etch vs self-etch adhesives. As Ohtsuki notes, the advantages and disadvantages of total-etch and self-etch bonds, especially comparisons between 5th generation, etch-and-rinse adhesives and 6th generation, 2-step self-etch bond (such as Clearfil SE Bond), have been comprehensively and frequently noted in the research literature. The general conclusions indicate significantly decreased post-operative sensitivity with enhanced long-term bond strength for the self-etch systems when compared to the technique sensitive etch-and-rinse bonding agent systems. The two major clinical benefits are especially demonstrated by Clearfil SE Bond.

Careful review of the literature will also show that for self-etch systems there are both “good self-etch” and “bad self-etch” systems, especially regarding long-term reliability and durability. There is a tendency to discuss differences between generations or types of bonding agents and generally link and view products by “generation” when, instead, we would choose a good adhesive, not the generation of adhesive.

Top researchers in adhesive dentistry, and Kuraray scientists, think that the most important factors to consider about “adhesion” is “quality and durability of the adhesion interface.” Even though we compare bonding agents in the same category, different types of adhesive monomers and different chemical compositions produce different quality adhesion layers. For example, if the chemical bonding to minerals in the tooth structure is not good, or if the adhesion layer absorbs too much water, an earlier degradation of adhesion layer will result.

Recent studies evaluating adhesion interface quality and bond strength showed that one 4th generation, 3-step, etch-primer-bond system showed equivalent quality to the results of Clearfil SE Bond. On the other hand, studies for technique sensitivity of SE Bond and other types/generations of bonding agents showed a significant advantage for SE Bond in clinical use. The studies included comparisons of products in other generations as well as products in the 6th generation. Kuraray is very honored and proud to have introduced 2-step, MDP-based bonding agents, products that have major market share and are the most reliable bonding agents with simple and easy clinical procedures. The newest self-etching technology from Kuraray includes antibacterial, cavity cleansing and fluoride releasing: new technology to reinforce our legendary self-etching technology for even better long-term reliability.

The company has initiated a series of discussions with key opinion leaders and top researchers in adhesive dentistry on how to educate dentists about the global research in adhesive technology. Findings from the first meeting in April 2009 are available on the Kuraray website at “We plan to continue these types of discussions, focusing on providing both scientific and educational information to help clinicians make decisions based on the most current information,” Ohtsuki concludes.

Kuraray America, Inc.
600 Lexington Avenue, New York, NY 10022
Phone: (800) 879-1676
Fax: (888) 700-5200

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