KATANA™ Zirconia ML (Kuraray Noritake Dental) was the first zirconia on the dental market with integrated shade gradation. First presented at IDS 2013, this material has revolutionized the world of zirconia. Over the course of time, KATANA™ Zirconia UMTL, STML and the change from ML to HTML completed the product portfolio. This article highlights the differences.

By Attila Kun, Hüde in Lower Saxony, Germany

In daily clinical and laboratory routine, we become aware of the diversity of characteristics of natural teeth. Natural teeth impress with their individual optical properties and characteristics, as well as the variety in their shape and texture. The challenge of imitating these aspects with ceramic restorations is a task that we handle in the lab with passion and motivation.

Imitation of the natural tooth requires the appropriate framework material (e.g. KATANA™ Zirconia HTML), an appropriate veneering ceramic or stain system (e.g. Noritake CZR™), along with sensitivity and skill. Although modern materials lay an important foundation, implementation of the restoration is to a large extent an artistic skill. In order to select the appropriate material, depending on the indication, the dental technician should pay attention to the facts and material science (material properties, parameters). Dental sensitivity and craftsmanship are also required for aesthetic realization of the prosthetic. Whether monolithic restoration, thin-layer veneer or individually layered, zirconia offers various advantages as a restorative material (e.g. good mechanical properties, high biocompatibility). In recent years, zirconia has been further developed and optimised through material modifications, and now, new zirconia generations are available. These materials are remarkable due to their translucency and outstandingly aesthetic properties. For certain indications, monolithic restorations can be realized in such way that the optical properties hardly differ from those of a veneered restoration.

Looking back at KATANA’s history

KATANA™ Zirconia ML (Kuraray Noritake Dental) was launched in 2013. This was the first zirconia on the market with a polychromatic shade gradient (ML = Multi-Layered) and has revolutionized the market since. The chroma and saturation of KATANA™ Zirconia ML decrease from cervical to incisal. The market responded very well to the polychromatic discs, so Kuraray Noritake Dental took the next step. In 2015, the KATANA™ family grew with two new translucent materials: KATANA™ Zirconia STML (super-translucent) and UTML (ultra-translucent). Translucency studies have revealed the very high light transmission of KATANA™ Zirconia UTML (43%) and STML (38%). It should be noted that the strength of the material drops with rising translucency. In 2019, KATANA™ ML became KATANA™ HTML. This change included a shade extension from 6 to 14 shades and the adaptation to the VITAPAN Classical shades to ensure an even simpler shade selection for the dental technician for an even better communication between dentist and dental technician. A few years back, the new zirconia stains (CZR™ FC Paste Stain, Kuraray Noritake Dental) were also launched on the market, thus perfecting the KATANA™ potpourri for highly aesthetic yet durable zirconia restorations.

The KATANA™ Zirconia STML layered structure.

Same translucency level as glass-ceramic (e.max Press LT).

With higher flexural strength than glass-ceramic (e.max Press LT).

Comparison of KATANA™ HTML, STML, UTML with comparable ceramic products (Kuraray Noritake overview graphics)

The Japanese word KATANA™ denotes a special kind of traditional Samurai sword. A special feature is the exquisite raw material. The KATANA™ sword combines expedient form with artistic design. We dental technicians aspire to this in our work too. KATANA™ Zirconia offers us the optimal foundation here. The multi-layered KATANA™ materials show a smooth progression of shade and brightness from cervical to incisal. Our experience shows that a functional and aesthetic restoration can thus be implemented in an efficient way.

Application of polychromatic zirconia

Fully anatomical, partially anatomical or as a framework — the polychromatic KATANA™ materials can be used in a variety of ways. The integrated shade gradient displays gentle nuances of enamel, dentin and cervical shade and, in the case of STML, also a translucency gradient. Depending on the indication, the zirconia blanks open up different ways of achieving aesthetic restoration. Especially for complex repairs and anterior restorations, the set-up is an indispensable foundation for us, because the "right" material alone is no guarantee for success. Precise planning is called for. This why we have to first conceive an overall picture. The surface structure, shape and contour are built up manually in wax and after a double scan the wax-up is virtually reduced. This creates a dentin structure or framework that can be milled out of the respective zirconia.

KATANA™ multi-layered materials allow the framework to become a shade-bearing foundation. The CAD construction of the restoration is made in a reduced anatomical crown shape. A dentin core is then milled from zirconia. The ceramic veneer is reduced to a minimum. For a vivid result, the framework can also be characterised with internal stain. Shrinkage during baking is not likely. Shade stability comes from the framework. In addition, the thin veneer layer ensures low shrinkage and lays the secure foundation for high stability and a low risk of chipping. The result is a natural looking restoration. Shine, warmth, naturalness — the optical properties mainly come from the KATANA™ framework!

Differences between and indications for KATANA™ Zirconia HTML, UTML, STML.

KATANA™ Zirconia HTML

KATANA™ Zirconia HTML has high flexural strength. Crowns and bridges (also with a large span) are typical indications. KATANA™ HTML is available in numerous shades, which cover individual requirements in the lab. The material offers optimal optical properties for frameworks. The incident light is transmitted and yet the stump is concealed. The flexural strength is about 1125 MPa.

The framework is designed following a cut-back. The challenge of ceramic veneers (CERABIEN™ ZR, Kuraray Noritake Dental) lies in the subtle, often diffuse, shade variety of the neighboring natural teeth. These characteristics can be implemented using the internal stain technique. The intensive stains can be mixed, for example with Bright (Dilution). Shade depth and three-dimensionality are created once the layering is then covered with luster compound. Luster compounds are a special feature of the Kuraray Noritake ceramic system. The compounds envelop the actual layering like a fine cocoon. Depth and liveliness are achieved thanks to the opalescent properties.

KATANA™ Zirconia STML

Aesthetic restorations need light and translucency, which KATANA™ Zirconia STML offers. The zirconia is modified by the manufacturer adding yttrium oxide, by varying the particle sizes, and increasing its translucency. KATANA™ Zirconia STML also has a polychromatic shade gradient from cervical to incisal. In addition to the shade intensity, its translucency also varies. Therefore, this material is well suited for frameworks in the anterior region (up to three units). The lower translucency in the cervical area is optimal for the shade-bearing framework foundation. The balanced combination of graduated chroma and translucency allow the optical properties of natural teeth to be imitated to the best effect. The flexural strength is 748 MPa.

KATANA™ Zirconia UTML

UTML offers the highest translucency in the KATANA™ family. By modifying the material, the optical properties come close to those of a glass-ceramic. This extends the range of indications to include monolithic restorations in the esthetically visible region, e.g. veneers. KATANA™ UTML has less chroma than conventional zirconia. This is achieved through a consistently high degree of transparency, which brings out the intrinsic shade of the dentin (chameleon effect). KATANA™ UTML is indicated for veneers, onlays or full-contour crowns. The flexural strength is 550 to 600 MPa.

For the purpose of phantom work, we used KATANA™ UTML to produce full-contour veneers. The wafer-thin veneers were milled with a minimum thickness of 0.3 mm. Despite the thinness of the layer, there were no fractures or chipping at the edges. Individual characterization was achieved through the staining technique. The milled veneers display beautiful transparency. In order to perfectly bring out the optical properties, an adhesive bonding cement (e.g. PANAVIA™ V5, Kuraray Noritake Dental) can be used for such delicate restorations.

Wafer-thin veneers (0.3 mm) of KATANA™ Zirconia UTML on the model.

Light and shadow

Something that is often said also applies to aesthetic restorations: "What is essential is invisible to the eye". In order to obtain a perfect ceramic restoration, besides layering, the lifelike, the shape, contour and surface texture are important factors. Therefore—no matter whether monolithic or veneered—suitable preparation of micro- and macro-textures should never be overlooked. The application of gold powder, for example, has proven to be helpful. Even the finest structures become visible under the gold powder. As with black and white images, the eye is not distracted by shade effects. After incorporating the textures and the final touches, manual polishing and adjustment of the shine was undertaken.

Conclusion

The KATANA™ Zirconia series allows us flexible application and the possibility of reproducing the variety of natural teeth in an efficient way. The materials differ in their translucency and mechanical properties.

• KATANA™ Zirconia UTML is suitable for full-contour crowns in the anterior and posterior regions, veneers, inlays/onlays and single crowns in the posterior region.
• KATANA™ Zirconia STML is ideal for crowns and small posterior bridges.
• KATANA™ Zirconia HTML is a high strength framework material for crowns and bridges.

With this selection of zirconia materials, dental technicians are well-equipped and prepared for everyday work and can devote themselves to dental precision work based on individual specifications.

Dental technician Attila Kun
Hannker Dental
Ludwig-Gefe-Straße 28
49448 Hüde
info@hannker-dental.de

If you're looking for a new way to keep up to date with the latest news from Kuraray Noritake, we now have a brand new app.

Available for free on both iOS and Android devices, the clean and tidy interface is the easiest way to follow our news updates and make use of cementation guides, find procedures and make use of colour simulations.

We are committed to bringing our users the latest news, interviews, research, in-depth features and exclusive content for both Dental Technicians and Dentists.

Check it out for yourself!

KURARAY NORITAKE DENTAL app is available on the Google play and App Store.

Our commitment to you:

Kuraray Noritake dental products offer dental professionals all over the world high-quality products using simple procedures with long-lasting results. With the COVID-19 outbreak, all of us are now going through difficult times which we were not prepared for. Our thoughts are with all those people who are affected by the coronavirus pandemic.

We, at Kuraray Europe GmbH, as the European sales office of Kuraray Noritake Dental Inc., feel a strong responsibility towards our customers and partners, colleagues and communities and we would like to inform you that, in spite of the challenges we are now facing, we will do our best to provide you with the services that you require:

1. Business as usual.

It is both important that we continue to provide products and services to all our customers and at the same time secure the safety of our employees. With that in mind, we have transitioned most of our employees not involved in manufacturing to working remotely and eliminated all non-essential and cross-border travel. This change should not impact in any way how you, our dear customers, contact us. We are ready, willing and able to support you. Clearly, to keep face-to-face interactions to a minimum, we will focus our communication on what is most convenient for you – either a phone call, through email or video chat (Skype, FaceTime or Google Hangout). Whatever is convenient for you!

2. Delivery

As of today, we have sufficient inventory for both dentists and dental labs, as well as reliable logistics. Thanks to our global network of dealer-depots, dental professionals all over the world will continue to have direct local access to our wide range of Kuraray Noritake Dental products. Kuraray Europe GmbH will exert every effort possible to deliver your orders on time. Parallel to this, we kindly ask you to make sure that somebody in your office will be available to receive the parcel. In case, for whatever reason this is not possible, please notify your supplier in advance.

3. Technical Services.
   Our technical service is available to meet your needs.

If there is anything else that we can do to support you, please let us know.

We wish you all the best. Take good care and stay healthy.

Sincerely,

Kuraray Europe GmbH

BU Medical

By Daniele Rondoni, RDT

A middle-aged patient sought dental advice because she felt uncomfortable with the aesthetic appearance of her upper front jaw, specifically regions 11, 12, 21 and 22. Additionally, she was not happy about the diastema between her upper central incisors.

Fig. 1: Initial situation.

The oral examination showed four crown regions (12-22) and revealed that all of them have deteriorated. Tooth 21 had undergone an endodontic treatment, while teeth 11 to 22 have been newly built up. Due to the deteriorated conditions, all affected teeth were taken into consideration in the planning and designing of new restorations, including the intention to close the diastema between the width-to-length-ratio for the incisors.

The best suitable material for a natural look in combination with a close gingival attachment to the restoration is, in this case, zirconia, because of its biocompatibility and gentleness to the gingival region. The KATANA^TM Zirconia series from Kuraray Noritake Dental, offers a line-up of high-quality materials combined with true-to-life aesthetics, due to its natural color gradient within the material.

Fig. 2: Preparations, showing discoloration in the cervical area of tooth 21.

Fig. 3: Occlusal view of the preparations.

Fig. 4: The four zirconia crowns after designing followed by milling.

Fig. 5: Result directly after sintering.

To achieve an even more natural-looking and aesthetic restoration, CZR FC Paste Stains were used externally on the zirconia surface.

Fig. 6: Characterization of the restoration.

As often done, Cervical 2 was used to give an orange tint to the cervical area, to accentuate even better the natural tooth gradation. For the incisal areas, Grayish Blue in combination with Value was used to enhance transparency and opalescence. Same procedure applied to the approximal areas. Mamelon Orange 2 was used to reproduce dark orange stain on the mamelons.

Fig. 7: Result after cementation of the four new zirconia crowns. Their shape and chroma blend harmoniously with the arch.

Fig. 8: The vestibular view showing natural-looking characterization.

During a period of five years, annual check-ups showed intact crowns and a healthy gingiva. Additionally, the durability of the restorations, including their mechanical and optical properties revealed no signs of deterioration.

Na Kuraray Noritake Dental Inc. estamos orgulhosos de que os nossos produtos estão a ser desenvolvidos utilizando tecnologias inovadoras, prestando atenção aos detalhes e tendo em mente as necessidades dos nossos clientes.

Estamos empenhados em oferecer produtos excepcionais que proporcionam aos profissionais dentários a flexibilidade para a auto-expressão e criatividade, acrescentando valor e proporcionando excelentes resultados estéticos a todos e cada um dos procedimentos.

Usabilidade, simplicidade e, claro, qualidade sempre em mente - fornecendo aos profissionais de medicina dentária materiais que tornarão a sua prática diária livre de stress.

Como prova de que os nossos produtos satisfazem as necessidades tanto dos dentistas como dos técnicos de laboratório, temos o prazer de partilhar convosco os Certificados CE de Sistema de Garantia de Qualidade Total que recebemos do Organismo Notificado. Estes podem ser descarregados abaixo.

Produtos para consultório dentário

Produtos para laboratórios dentários

As the manager of a dental practice and the co-founder of the Deutsches Zahnärztinnen Symposium (DZÄS), an event that provides a forum for female dentists in Germany, Dr Frederike Fehrmann is an extremely busy woman. In this interview, she discusses her experiences as a woman working in dentistry and offers advice for those who are considering entering the field.

How did you decide to enter the field of dentistry?

I knew very early that I wanted to study dentistry. My mother is an orthodontist and I always liked what she was doing. During my studies, though, things looked different—I wanted to do oral and maxillofacial surgery for a period. But then I was offered the dental practice where I now work, and though it was different from what I had expected, I was still able to develop my skills in many directions, arriving finally at CAD/CAM and laser dentistry, which have been my favourite areas in recent years.

My professional life is constantly changing and developing, and that is what makes it exciting. High-tech dental surgery is exactly what I want to do and work with.

In your experience, are there any advantages or disadvantages to being a woman in dentistry? Have these changed over time?

I think dentistry is great, but it’s the same in this field as in many other professions in which women work. We often have a double burden simply because of our responsibility to bring the next generation into the world. This is a topic that has been on my mind for a long time. In fact, the DZÄS will be hosting a symposium in Frankfurt later this year where we will highlight the balancing act between technology and mindfulness, between career and family. I’m looking forward to it very much.

In my experience, women tend to have certain advantages—for example, we often find it easier to deal with children as patients than male dentists do. However, we still have to assert ourselves constantly. But things are changing. At the university near us, there are hardly any male dental students. It is time to rethink and adapt dental education to empower women to fulfil their potential.

How important is it to have peers and mentors with whom you can discuss dental issues?

Having other women with whom one can exchange ideas is worth its weight in gold. Sometimes you discuss your problems and suddenly find there is a simple answer that you yourself would not have thought of, one that makes your life easier. It’s possible to do without a mentor, of course, but things do become more difficult. Both peers and mentors make you strong and help you progress continuously. Besides, women often talk and listen differently and understand even without words.

What qualities and skills do you think are needed to succeed in the dental world?

I have had feedback from many patients who say that they like to see women providing treatment, as we can often read between the lines and might be more likely to recognise when they are afraid, for example.

Nevertheless, we frequently have to prove ourselves repeatedly. How often haven’t I heard the questions, especially as a young professional, “Are you able do that? Are you strong enough to remove that tooth?” I don’t think that a male dentist would be asked this.

Do you have any advice for girls and women considering a career in dentistry?

Just do it! Network and never, ever give up. Find a focus, something you do better than everyone else. Find mentors and colleagues who can help and guide you when needed. Educate yourself and find out what you’re passionate about.

Which Kuraray Noritake products do you employ in your daily workflow?

I use both KATANA™ AVENCIA™ Blocks and KATANA™ Zirconia Blocks in my CEREC workflow to produce CAD/CAM dentures. A colleague who works a lot with Kuraray Noritake told me about these blocks, and so I tried them out. The zirconia blocks impressed me by being super-translucent and variable in their colour texture. Their fit is excellent and the CEREC workflow is easy. The AVENCIA™ blocks are very simple to use because after milling they only need to be polished, not fired. This is particularly useful when supplying inlays.

Though traditionally a male-dominated discipline, dentistry is increasingly welcoming women into the fold, and female dental students now outnumber their male counterparts in many countries. The Paris-based dental surgeon Dr Anne Longuet Tuet recently spoke with Kuraray Noritake Dental about the challenges that women may face in dentistry and what it takes to succeed in this environment.

Dr Longuet Tuet, how did you decide to enter the field of dentistry?

I have always wanted to work in a medical profession. Initially, I wanted to be a veterinarian, but then, at a certain point, I spent a lot of time in a dentist’s office. She was also a woman, a teacher at the local university, and I saw what she could do and was inspired to help people in a similar way in order to let them smile again.

In your experience, are there any advantages or disadvantages to being a woman in dentistry? Has the situation changed over time?

I regularly lecture, and this still tends to be a very male-dominated arena. For example, at a lecture last year in Tunis, there were ten of us on stage and I was the only woman. Being a female lecturer can sometimes be a bit of a disadvantage, as we often have to work harder than the average male lecturer to prove ourselves and receive the same level of recognition. However, this will hopefully change in the future as more women prove themselves to be highly capable in this field.

Do you have any female mentors or role models in dentistry that you look up to?

Someone I really admire is Dr Francesca Vailati, who has contributed so much to modern adhesive dentistry through her lectures and research articles.

How important is it to have peers and mentors with whom you can have discussions?

I think it’s very important to have female peers and mentors, but it’s also worth remembering that men should also be part of your network. It’s nice to see other women when I give lectures or attend conferences, of course, but I also have plenty of male peers I admire and who help me grow professionally.

If you don’t consider men for mentorship, you can really limit yourself in the dental world, so it’s better to be open-minded in this respect. Good mentorship isn’t necessarily related to sex but instead to knowledge, experience, charisma and a willingness to share your expertise.

What do you need to succeed in the dental world?

I think the most important quality is a commitment to lifelong learning. It’s dangerous to think that you know everything there is to know about dentistry—there’s always an area in which you can improve. Even when you’re at a certain level and have been practising for many years, there’s always some new technology or technique that you can learn or something that you can improve on.

Of course, this is not just on the personal level. Dental materials and technologies are constantly evolving, and if you stop learning about them, you stop being up to date, right?

This is especially true if you work in adhesive dentistry. You need to be aware of the new bonding products and materials that are introduced to the market, since this can be a way of improving your work and the cases you treat.

How were you first introduced to Kuraray Noritake Dental’s wide range of adhesive solutions?

It was about four years ago, just after I really began to develop my restorative and adhesive dentistry skills. I was looking for a way to improve my composites and the way I bonded my ceramic restorations, and a friend of mine told me that the company’s CLEARFIL MAJESTY™ range of composites was very good. I was sent some samples soon afterwards and have been using the company’s products ever since.

Which Kuraray Noritake products do you use in your daily workflow?

Since 80% of my work at the practice is now restorative dentistry, I use the CLEARFIL MAJESTY™ ES-2 composite every day, as well as Kuraray’s PANAVIA™ adhesive cement. In addition, the dental lab that I work with uses KATANA™ Zirconia regularly to manufacture dental crowns.

This BOND edition covers the pursuit for durable dental aesthetics.

Unique insightful articles from renowned clinicians and researchers of the likes of Prof. Bart Van Meerbeek, Prof. Dr. Florian Beuer and Dr. Hendrik Zellerhoff are waiting for you. 

BOND | VOLUME 6 | 03/20

We post the BOND also here for your convenience; Enjoy!

Previous versions:

BOND | VOLUME 5 | 05/2019

BOND | VOLUME 4 | 06/2018

BOND | VOLUME 3 | 10/2017

BOND | VOLUME 2 | 04/2017

BOND | VOLUME 1 | 12/2016

To achieve excellence it is crucial to know the properties of modern materials and their correct clinical procedure. With this premise, surprising clinical results can also be achieved by combining different materials in the same clinical case.

This clinical case follows the aesthetic request of the patient who wanted to solve the pathology concerning the incisors with a direct composite restoration on 2.1 and a KATANA^TM STML crown on 1.1.

Following the mock-up the patient wanted larger incisor shapes with a strong character. The 2.1 was restored only with the MAJESTY^TM ES-2 Classic A2 mass exploiting the extraordinary ability of mimicry that comes from the Kuraray Noritake Dental light diffusion technology - LDT. The restoration on the 2.5 was performed with a CAD/CAM hybrid ceramic block - KATANA^TM AVENCIA^TM.

KATANA^TM AVENCIA^TM Block was characterized with a staining resin before cementation with the new PANAVIA^TM SA Cement Universal. PANAVIA^TM SA Cement Universal includes in its formulation a new type of silane coupling agent – LCSi monomer and this ensures strong and durable chemical bond to glass ceramics and composite resins without pretreatment with silane.

A strong and durable bond between the tooth and the restoration is a decisive factor influencing the long-term performance of dental restorations. The quality of the bond, however, is not only affected by the bonding agent or cementation solution used, but also by the condition of the bonding surface. For those who would like to ensure clean tooth and restoration surfaces in an easy way, Kuraray Noritake Dental has developed KATANA™ Cleaner, a universal cleaner with MDP salt and a pH of 4.5 for intra- and extra-oral application.

It has been proven that proteins present in saliva and blood have a negative effect on the performance of dental adhesives. Especially in indirect procedures, however, it is impossible to keep the bonding surfaces free of oral fluids. At try-in at the latest, the prepared tooth and the restoration are contaminated and need to be cleaned. Rinsing with water does not have the desired effect, and even with many available cleaners, a certain amount of proteins are usually left on the surface. Tests show that by using KATANA™ Cleaner or by sandblasting, the desired high cleaning effect needed is obtained, without compromising bond strength. This is true for KATANA™ Zirconia restorations, while KATANA™ Cleaner also leads to the desired results on dentin and enamel – surfaces in the oral cavity for which sandblasting and most of the other cleaners are not indicated.

The use of KATANA™ Cleaner offers yet another advantage: the cleaning procedure is extraordinarily simple, quick and neat. The universal cleaner comes in a bottle with an innovative flip-top cap, enabling single-handed dispensing onto the dish. It is then rubbed into the surface of the restoration and the prepared tooth structure or the abutment for ten seconds, rinsed with water and dried. Thanks to the high surface activity of MDP salt, these ten seconds are sufficient to remove the proteins on the substrate almost completely, creating conditions very similar to those found on a non-contaminated bonding surface. Subsequently, the selected bonding agent or cementation solution – e.g. PANAVIA™ V5 or PANAVIA™ SA Cement Universal – is applied according to the maufacturer’s usage instructions.

The result is a strong long-lasting bond, which gives users a peace of mind. Pilot users who have already tested the product agree that KATANA™ Cleaner is the easy way to optimise bond quality and streamline any adhesive procedure.