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“The multi-layered aspect of KATANA Zirconia is excellent”

In recent years, zirconia has emerged as the preferred choice for dentists who wish to perform restorative procedures with a reliable and metal-free material. With the recent development of multi-layered aesthetic high-translucency options, zirconia’s popularity has further increased. In comparison to the opaque whiteness of older generations of zirconia, these newer versions have an enhanced appearance and functionality that makes them suitable for natural-looking anterior restorations.

Kuraray Noritake Dental’s KATANA Zirconia disc range is made with a proprietary zirconia powder—processed in-house—that gives it its natural appearance. Suitable for zirconia prostheses, from single crown to full arch, it is an ideal option for restorations in both the anterior and posterior regions. We spoke with Dr Imad Ghandour, a prosthodontist with a strong scientific background and a private practice in Le Cannet in France, about his experiences with the KATANA Zirconia range in restorative procedures.

Dr Ghandour, when did you first start using zirconia as a material for your restorations?

In 1998, when I was still sintering manually, I began using zirconia alumina. It was nice to have an alternative to metal alloys that was much more aesthetic. From 2003, however, I started with VITA blocks, but only for frameworks—I would still build up with ceramics. Now, with so much of dentistry being digitally focused, there is a need for a material that can be milled without changing anything in the morphology of the teeth. Why? Because we need to be able to reproduce the treatment plan as accurately as possible. Simply put, the KATANA Zirconia range solves this need for me.

With respect to dentistry being digitally focused, how has this changed the role of the dentist regarding performing restorative procedures?

Well, it is clear that we have entered the age of digital dentistry. Around 80 per cent of restorations are conducted via CAD/CAM systems and without dentists even touching the materials themselves. There are great advances being made in the technologies that are available for everyday use in dental practices worldwide, and many of them can be used to assist dentists performing restorative procedures. It is important, though, to keep in mind that these technological advancements alone will not lead to better results—they should supplement the requisite hands-on skills and techniques that all dentists must first learn. With this base of fundamentals, we can then use digital dentistry to make restorative procedures more predictable and reproducible. Of course, to ensure the best results in restorative procedures, dentists also need to use the materials that have the best aesthetic and mechanical properties.

For how long have you been using Kuraray Noritake Dental’s KATANA Zirconia range, and what has your experience been?

I have been using KATANA Zirconia for a little bit more than one year. In that time, I have primarily used the KATANA Zirconia STML (Super Translucent Multi Layered) line and have been pleasantly surprised by how natural-looking the restorations I have made with the material are. For example, when I sinter a crown made of Katana Zirconia STML, I am amazed at how much the sintered material is reminiscent of a pearl—it truly brings to mind the idea of one’s teeth being one’s pearly whites.

When using KATANA, how do you ensure that you select the correct shade to achieve a natural look?

Firstly, no one—not a dentist nor a dental technician—can be absolutely certain that the shade and chroma of the restoration that is in one’s hand will be the same once it is in position in the oral cavity. This is due to the complexities of the oral environment—the pinkness of the gingivae, for one, can have a large impact on how the restoration appears, often making it seem far duller than it does in the light of a dental laboratory. This can cause dental practitioners to compensate and make prostheses that appear far brighter than they will when they are in place.

With a product like KATANA and its related glazing materials, however, I can create crowns and other restorations that have an optimal fluorescence and translucency and are able to maintain their shading better than any other ceramic material I have used. I am able to select a shade with the confidence that it will look exactly the same once placed inside the mouth, with its chroma remaining unabsorbed by the gingiva. Achieving a natural look, then, depends on choosing a shade that is as close to that of the surrounding dentition as possible. Since KATANA Zirconia UTML (Ultra Translucent Multi Layered) is available in 16 standard shades and a further four enamel shades, there is no shortage of options in this regard.

How does the multi-layered technology of KATANA Zirconia help you to achieve optimal and natural-looking aesthetic results?

Well, firstly, the layering of the material is designed to replicate the colour and translucency progression of natural teeth, which allows for restorations to blend in as much as possible. This multi-layered technology has also proved itself to be very handy when I am sintering crowns made of KATANA Zirconia. Simply put, if one sinters a crown quickly, it will be a little more opaque. If one sinters it at a higher temperature and quite slowly, it will be much more translucent. The multi-layered aspect of KATANA Zirconia is excellent in that it gives me the ability to make restorations more or less translucent depending on what is required.

Get to know the CLEARFIL MAJESTY family

Kuraray Noritake Dental is proud to present the CLEARFIL MAJESTY family, a series of universal composites designed for reliable, natural-looking restorations. With its brightness-based shade system for direct composites, CLEARFIL MAJESTY is another symbol of our company’s dedication to research and development, promising ease of use and reproducibility for the dentist.

CLEARFIL MAJESTY ES-2 Classic and Premium

A universal nano-hybrid composite resin with a high refractive matrix, CLEARFIL MAJESTY ES-2 Classic was introduced to the world at the 2013 International Dental Show in Germany. It combines easy sculpting with a predictable and aesthetic finish for a composite that will benefit both the dentist and the patient. With 15 precisely matched VITA shades and some special shades for whitening, it is suitable for a range of anterior and posterior restorations, including all cavity classes, composite facings, intra-oral repairs of fractured crowns and bridges, and corrections of tooth positioning and shape. CLEARFIL MAJESTY ES-2 Classic uses Kuraray Noritake Dental’s Light Diffusion (LD) technology to accurately replicate the diffusive properties of dentine. This feature means that restorations blend in with the existing tooth structure, rendering them virtually undetectable.

Through its fixed shade combinations of dentine and enamel, CLEARFIL MAJESTY ES-2 Premium is able to cover three VITA shades at once, making natural-looking restorations easily achievable. This dual-layer aspect means that there is an optimal built-in pairing of enamel translucency and dentine opacity, eliminating the need for any complicated shading schemes. By also incorporating LD technology, CLEARFIL MAJESTY ES-2 Premium is able to adjust the colour saturation and tint to that of the neighbouring tooth issue automatically. The small particle size of its proprietary nano-filled composite ensures easy polishing with a durable gloss, promising an aesthetic and seamless restoration.

CLEARFIL MAJESTY ES Flow

A light-curing universal, flowable composite, CLEARFIL MAJESTY ES Flow combines easy handling, high polishability and impressive mechanical strength to provide a material for all cavity classes. Thanks to Kuraray Noritake Dental’s silane technology, its submicron filler particles adhere reliably to the resin and maintain long-term stability. These small yet durable particles allow restorations made with CLEARFIL MAJESTY ES Flow to keep their high level of enamel gloss over time, with special cluster fillers providing a light diffusion property similar to that of natural teeth. The gloss itself is remarkably simple to achieve: just wipe the cured resin with an ethanol-moistened gauze or cotton roll to produce a smooth surface.

CLEARFIL MAJESTY ES Flow’s excellent handling characteristics allow for better sculpting. The material does not stick to the needle tip or to any instruments, only adhering to the area to which it is applied, and the proprietary design of the syringe itself minimises air bubbles when dispensing. A truly universal composite, CLEARFIL MAJESTY ES Flow allows dentists to create highly aesthetic restorations with ease.

Kuraray Noritake Dental concludes a patent license agreement with 3M In March 2018, Kuraray Noritake Dental Inc. (President: Kiyoyuki Arikawa), with its Head Office in Chiyoda-ku, Tokyo, concluded a license agreement with the 3M Company, whose Head Office is in Saint Paul, Minnesota, USA. The agreement concerns a patented method for producing multilayered ceramics, European patent No. 2024300, held by Kuraray Noritake Dental Inc.

Summary of Kuraray Noritake Dental Inc. ceramic business

Kuraray Noritake Dental Inc. launched the zirconia disc that has been commercialized through the use of our layered ceramic production method in 2012. The product has multi-layered structure with four different colored zirconia powders that feature a smooth transition of color gradation between layers. We took advantage of the dental ceramic coloring technology we had accumulated through the development of porcelains. Success was achieved in controlling the shrinkage of the layers by optimizing the amounts of pigments added, thereby achieving great accuracy in terms of adaptation. In 2015, we also launched a new series zirconia which has the high degree of translucency of natural tooth enamel and is suitable for the esthetic restorations of anterior teeth. In January 2018, zirconia block joined the zirconia family as our new solution for the fabrication of zirconia restorations. This new product achieves a well-balanced combination of appropriate mechanical properties and good esthetics with a short baking time. Kuraray Noritake Dental Inc. is committed to developing new dental materials that contribute to the dental industry. Our products have become even more competitive on the global market because of our intense pursuit of technological innovation.

Read the official statement here

No other resin cement offers such ease of use and consistency in procedure. Indeed, the unrivalled simplicity and predictability of PANAVIA V5 is nothing less than astonishing.

Always the same cementation procedure. Always the special PANAVIA V5 Tooth Primer for the pretreatment of the tooth. And always CLEARFIL CERAMIC PRIMER PLUS to prime the restoration. 

In 1983, Kuraray introduced the PANAVIA EX resin cement and, with it, our patented MDP adhesive monomer. Since then, the MDP monomer has repeatedly been clinically proved and has set the industry’s adhesive standard for over 30 years. PANAVIA V5 is the newest addition to the PANAVIA cement line and sets a new adhesive benchmark for resin cements by providing self-cure dentine bond strengths equal to our gold standard light-cure bonding agent CLEARFIL SE BOND.

PANAVIA V5 is able to provide strong bonding not just to hydroxyapatite but to metals and zirconia as well. It can be used for all clinical cementation indications, including on crowns, veneers, inlays/onlays, bridges, crowns/abutments on implants, and posts. With PANAVIA V5, you always follow the same procedures prior to prosthetic cementation: roughen and prime the prosthesis, prime the tooth, and apply the cement to the prosthesis.

Aesthetic stability in shading 

When it comes to maintaining shade in aesthetic cementation, conventional composite cements tend to discolour over time. With PANAVIA V5, Kuraray Noritake Dental presents an amine-free paste in five different shades—Universal (A2), Clear, Brown (A4), White and Opaque (only in self-cure mode)—that has been scientifically proved to demonstrate a lower level of post-curing colour variance than amine-based cements do. In addition, the new PANAVIA V5 try-in paste allows you to accurately simulate the shading of your cementation before it has been performed. As part of Kuraray Noritake Dental’s continued commitment to excellence in adhesion, this combination aims to enable the continued stability and natural appearance of the cement shading after curing.

PANAVIA V5 Tooth Primer

Almost all dual-cure resin cements available have been scientifically demonstrated to require light curing to achieve an acceptable bond strength. Thanks to Kuraray Noritake Dental’s focus on research and development, the MDP monomer-based PANAVIA V5 Tooth Primer contains a new catalyst that solves this issue. It provides an accelerated curing process from the moment the cement touches the primer, which, in turn, leads to a high degree of conversion from monomer to polymer. PANAVIA V5 presents a milestone in adhesion, as it offers improved bond strength for all tooth structures, even when used in the self-cure mode.

Prime with CLEARFIL CERAMIC PRIMER PLUS

PANAVIA V5 is designed for use in conjunction with CLEARFIL CERAMIC PRIMER PLUS, a stable universal primer that contains both Kuraray Noritake Dental’s original MDP monomer and a silane monomer. This allows it to bond to all silica-based ceramics (including lithium disilicate), zirconia, composites and metals. It provides excellent bond strengths to all of these materials, as well as procedural simplicity.

To find out more about integrating PANAVIA V5 into your restorative workflow, visit www.kuraraynoritake.eu/en/panavia-v5.html

PRESS RELEASE

EXPERTS PRESENT IMPORTANT FINDINGS ON THE ADVANCED BONDING PROPERTIES OF THE NEW ONE-BOTTLE UNIVERSAL ADHESIVE: CLEARFIL™ UNIVERSAL BOND QUICK

Hattersheim, Germany – January 2017  

The 2nd December 2016 saw the annual Kuraray Noritake Expert Symposium in Frankfurt with more than 60 leading adhesives and composites experts from universities all over Europe meeting to discuss and share new advances in the world of adhesive technology, notably CLEARFIL™ Universal Bond Quick: the new one-bottle universal adhesive by Kuraray Noritake Dental which is to be launched in Europe in February. Prof. Dr. Bart Van Meerbeek from the KU Leuven - BIOMAT - University Hospitals Leuven/Belgium, acted as Symposium Moderator.

Starting off the day’s proceedings, Yusuke Fujimura, Technical Manager and Chief Developer at Kuraray Noritake Dental demonstrated how, unlike most other bonding agents, CLEARFIL™ Universal Bond Quick works instantly, removing the need for waiting time, extensive rubbing or multiple layer application. This was followed by Professor Dr Bart Van Meerbeek who discussed the problems associated with conventional total-etch methods whereby strong phosphoric acid is applied to the dentin, dissolving the natural tooth protector hydroxyapatite and exposing the collagen matrix. He posed the fundamental question:” Why demineralise the tooth with strong acids only to remineralise it again?”

Also on the agenda were four individual studies, each tested far over and above the legally-required ISO standards, providing insights into the fact that the longevity prognosis for bonded restoration is absolutely dependent on both the quality of the adhesives and the effect of the procedural steps. Luc Randolph, Materials Research Engineer at the University of Louvain-la-Neuve/Belgium, reported on shear bond strength tests using the new universal adhesive CLEARFIL™ Universal Bond Quick concluding that: “Among the all-in-one universal alternatives, the new CUBQ technology appears equally efficient despite the absence of waiting time after application, making it a more user-friendly and convenient option than its competitors.”

Prof. Dr. Amélie Mainjot from the University of Liège/Belgium went a step further demonstrating highly positive bond results for zirconia which showed, even after thermocycling, comparable bond strength to Vita Mark II class-ceramic instead of pre-test failures when not treated with CLEARFIL™  Universal Bond Quick.

Finally, Prof. Dr. Mutlu Özcan from the University of Zurich/Switzerland, concluded that, whereas the described method of air-abrasion increases the adhesion results for the majority of adhesives, air-abrasion may not be needed for CLEARFIL™ Universal Bond Quick.

Over the course of the day the speakers presented many enlightening research results which participants were able to take away with them. However, before they left, Prof Van Meerbeek called for a panel discussion so that speakers could collaborate with the audience on requests for future development and findings.

CLEARFIL™ Universal Bond Quick is launched in Europe on the 1st of February 2017. 

Read the full report: Kuraray Noritake Symposium Report (PDF: 360 Kb)

Kuraray celebrates its 90th anniversary in 2016. We take the opportunity of this occasion to offer you a glimpse of the history of Kuraray from a new perspective. The name Kuraray represents more than 8,300 employees and an annual turnover of approximately 3.7 billion euros. Kuraray was founded in Kurashiki, Japan, in June 1926, by Magosaburo Ohara. Kuraray began with the domestic production of Rayon, a synthetically produced cellulose fibre referred to as artificial silk, a new and innovative product at the time. 

The name KURARAY is derived from the location: Kurashiki and the product manufactured: Rayon. The development of this branch of production developed very quickly in Japan, with many other major manufacturers establishing themselves during this period. Whereas others recruited their technicians and experts from elsewhere, Kuraray established the Kyoko Research Laboratory, which was managed by the University of Kyoto to generate expertise and support for the development of the required technologies. Ohara also committed himself to cultural and social projects. The building of an art gallery and the financing of an orphanage represent only two of his many projects in Kurashiki. The Ohara Museum of Art was the first private museum of Western art in Japan.

Ohara considered the dreadful conditions in which employees commonly worked and lived at the time to be unacceptable; he was not a profit-driven employer, and attempted to solve such issues. He ensured that decent accommodation, fitness facilities and nursery schools were built to provide young employees, or families who had left their homes to work for Kuraray, with everything they needed for education and a healthy and culturally rich lifestyle.
One of the largest general hospitals in the west of Japan, the Kurashiki Central Hospital, was originally founded by Kuraray to promote the well-being of employees and their families. It is still considered to be one of the most famous hospitals in Japan.

With the production of Kuralon in 1950, developed from the in-house manufactured products PVA and vinyl acetate, Kuraray expanded to become the specialist chemical company it is today. Always intent on making a contribution to the good of society, Kuraray addressed the subject of environmental protection very early on. The visionary Ohara was aware of the seriousness of environmental pollution, and made great efforts to prevent it.

Internationally too, Kuraray has remained aware of its social responsibilities. After the war, a production facility was opened in China which helped to improve the poor post-war living conditions of the Chinese population.
Today, Kuraray is a leading global manufacturer of the specialist chemicals used in many aspects of daily life. Kuraray has always viewed its employees as its most important asset, and continues to do so to this day.

During my presentations I am often asked why clinical research into bonding systems is conducted using class V situations.

The non-carious class V lesion is most suitable for this type of research for a number of reasons. Unquestionably, the main reason is the fact that such lesions present little or no macro retention. It must be remembered that if a cavity presents macro retention, loss of adhesive strength in the bonding interface will not automatically lead to loss of retention.

Other major reasons (in no particular order) are that such lesions occur relatively often, but also that in general they are situated in an easily accessible area and do not demand complex restoration technology. The configuration factor is low (ratio between free and bonded areas) and does not therefore cause much shrinkage stress. In addition, both enamel and dentine are involved in the restoration, although in some studies efforts are made to limit bonding to enamel (for example, in Van Dijken et al., Clinical long-term retention of etch-and-rinse and self-etch adhesive systems in non-carious cervical lesions. A 13 year evaluation. Dent Mat 2007).

The restoration is then re-assessed periodically. Obviously, loss of retention is considered, and sometimes restorations are also assessed on marginal integrity, marginal discolouring and aesthetics.

Whenever a restoration goes wrong, this is noted as a failure. The survival/lifetime of restorations is expressed in an Annual Failure Rate; for example, an AFR of 4.6 means that, on an annual basis, 4.6% of the restorations failed in the course of the study.

Phosphoric acid, sometimes also called orthophosphoric acid, is a substance that is used frequently in the practice of dentistry, mostly in concentrations between 30 and 40%. It is a proven substance for the etching of enamel (Buonocore 1955). It also entails hazards, because contact with the eyes and skin may cause severe irritation, blistering and burns.

The substance should only be applied where its use is intended, and proper control is of the essence. The use of a coloured gel is therefore recommended, preferably of a thixotropic type. The application of a cofferdam is also definitely recommended, and the patient should wear protective glasses ( the practitioners should obviously also wear protective glasses). When removing the etching gel, the main volume should first be sucked away using a saliva ejector without a cap. The area should then be rinsed clean with a spray mist suction device under continued suction.

If the etching gel should unintentionally get onto the skin or, even worse, into the eyes, the affected area should be rinsed with plenty of water until the patient no longer feels any pain in the affected area. In such a case, it is recommended that medical assistance be sought.

This article is based on a publication in the British Dental Journal Vol 217 No.2 Jul 25 2014
Link to the publication. 

I would like to refer to a recently conducted study by Garcia et al. to reply to this question, which derives from practice. The study examines the effect of three desensitisers on the bonding strength to dentine of a composite cement.

The study concluded that the effect is dependent on the material. Gluma Desensitizer (Heraeus Kulzer) and Super Seal (Phoenix Dental) decreased the bonding strength, whereas TeethmateTM Desensitizer (Kuraray Noritake) improved the bonding strength. The researchers obviously consider it necessary to conduct further research into the workings of TeethmateTM Desensitizer, a cement that contains calcium phosphate.

Clinical significance:

TeethmateTM Desensitizer, a material containing calcium phosphate, may serve as a useful new generation of desensitisers for use prior to the cementing of indirect restorations.

Click here for the research abstract.

Clinically proven

13 years of clinical evaluation show exceptional results for SE Bond.

The clinical effect of CSE in non-carious class V lesions remained excellent after 13 years. Selective etching on the enamel margins had only a limited positive effect on marginal integrity and absence of marginal colouring.

This is the conclusion of the study that was published last year:

A thirteen-year randomised, controlled clinical trial of a two-step self-etch adhesive in non-carious cervical lesions, by M. Peumans and colleagues from KU Leuven BIOMAT. Dental Materials 31 (2015) 308-314

This publication comprises the evaluation of the study after 13 years; the evaluations after 3, 5 and 8 years have already been published. NCCL’s (non-carious cervical lesions) are the most suitable treatments for the clinical testing of bond effectiveness. Only a limited number of studies with long-term results are available, and 13 years is the longest evaluation period to date.

So far, CSE is the only bonding to perform so well over such a long period of time.

Loss of retention is the most objective parameter in establishing the effectiveness of bonding in such a clinical test. The 13 year retention rate of CSE was high in this clinical test: no less than 96%!

In the course of this study, half the cavities were treated with CSE without the etching of the enamel margins with phosphoric acid; the other half were treated with selective etching of the enamel. Etching or non-etching of the enamel margins had no effect on the retention rate.