429 Too Many Requests

An interview with Dr. Tomohiro Takagaki, DDS, PhD by Dr. Jorge Espigares, DDS, PhD

Due to its increased usability, one-step universal adhesives are becoming more popular and are the choice of many clinicians all around the world. Nonetheless, some studies have shown lower performance for one-step universal adhesives than previous generations.

Dr. Jorge Espigares, DDS, PhD, Planning and Development Department at Kuraray Noritake Dental Inc., interviewed Dr. Tomohiro Takagaki, DDS, PhD, lecturer and former assistant professor at Tokyo Medical and Dental University (TMDU), pioneer in the field adhesive dentistry, author of many publications, and currently lecturing at Asahi University, Japan.

Dr. Takagaki, in your opinion, what are the most important factors for a good and durable adhesion?

Dr. Takagaki: Good resin infiltration (penetration) and good polymerization are essential factors for good bonding. This is the basic concept for the formation of the hybrid layer. Additionally, there are other important factors such as low water sorption for bonding durability and the demineralization depth, which should be the same as the depth that the resin is capable of penetrating to.

Nowadays, the trend seems to be one-step universal adhesives. Do you believe that this reduction in steps has brought any limitations compared to previous generations?

Dr. Takagaki: Traditionally, one-bottle adhesives are too hydrophilic. This hydrophilicity also brings high water sorption, therefore the durability of the interface is compromised. At TMDU, we did not accept one-step bonding agents in clinical usage based on results we obtained in our research in that area.

Water sorption/solubility of different bonding agents.
Data provided by Tokyo Medical and Dental University.

What do you think of the new MDP-Amide chemistry (included in CLEARFIL™ Universal Bond Quick) for overcoming such limitations?

Dr. Takagaki: The MDP monomer has proved through research to be the best monomer for adhesion to tooth substrate. Nowadays, many manufacturers include MDP. Although the MDP purity and performance differs from Kuraray Noritake’s original one, in one-step bonding agents only MDP is not enough. The differential factor is the amide monomer that provides the desired high penetration and low water sorption.

You and your work at TMDU are very well known in the field of adhesive dentistry. Did your research show results that would support the above mentioned statements?

Dr. Takagaki: In our research results, we observed indeed a lower water sorption compared to previous one-step generations. Actually, we were surprised to see water sorption levels equivalent to the two step bonding agent gold standard: CLEARFIL™ SE BOND. (1. Graph). The amide monomer behaves as hydrophilic before the polymerization and as hydrophobic after, which is the desired situation for one bottle self-etching systems.

Would you recommend, therefore, the usage of universal bonding agents in daily practice?

Dr. Takagaki: Yes, but as mentioned, the MDP-amide chemistry is essential. It is noteworthy that another company is also using an amide monomer. However, our results at TMDU indicate that the performance in terms of penetration is not that good. Actually, we still saw lesion formation with that other company’s amide. Kuraray Noritake’s MDP-amide chemistry is the only one that avoids lesion formation (2. SEM images). In addition, CLEARFIL™ Universal Bond Quick releases fluoride that helps protecting the interface degradation and its “no waiting time” makes it ideal for challenging conditions as pediatric and/or geriatric patients.

Let’s get out of the laboratory, according to your clinical experience is there any extra advice that you could provide for a reliable adhesion?

Dr. Takagaki: One important point that sometimes is missed is to properly air-dry the solvent for at least 5 seconds after the bond application. I also recommend selective enamel etch for achieving aesthetic margins, even if all universal bonding agents allow self-etching. Finally, I would like to talk about simplicity. We dentists tend to shorten the necessary time and sometimes the rubbing time is not respected. With CLEARFIL™ Universal Bond Quick, our research showed not significant difference in bond strength with rubbing time (3. Graph). Therefore, it reduces the risk of error, allowing consistent results. I believe that simplicity is required so the fact that CLEARFIL™ Universal Bond Quick and PANAVIA™ SA Cement Universal can cover direct and indirect restorations, is ideal for daily practice. CLEARFIL™ Universal Bond Quick achieves what I am looking for in my practice: easy, quick and reliable.

Although the amount of available universal adhesives market is large, key properties like the ones above-mentioned may help in the complicated process of selecting a one-step adhesive that offers the best performance, simplicity, consistency and predictable results.

Bond strength upon rubbing time. Data courtesy of Tokyo Medical and Dental University.

PROVEN SCIENCE AND ARTISTRY LEAD TO QUALITY

Kuraray Noritake Dental enables the unique in-house production of raw materials. In contrast to our competitors, who source their raw materials externally (well known: Tosoh Cooperation), Kuraray Noritake Dental distinguishes itself by its unique in-house production of zirconia raw materials. Many years of expertise in manufacturing the company’s own powder have brought the material quality of KATANA™ to completely new dimensions, not only by controlling the degree of purity and particle sizes, but also by creating an optimal balance of binders, color pigments, stabilizers and other ingredients.

“WE CONTROL EVERY DETAIL.”

KATANA™ Zirconia STML NW with CERABIEN™ ZR FC Paste Stain
Sergio R. Arias DDS, MS Sung Bin Im, MDC, CDT

NEW SINTERING SCHEDULE

In addition to the new sintering programs, the traditional KATANA™ sintering programs can also be used, if desired.

The Function that becomes aesthetics

Italian dental technician, CDT Stefano Lograno, demonstrates how it is possible for the medical-technical prosthetic team to adopt a protocol from diagnostics to cementation, in which aesthetics can be functionally guided in a simple, predictable and standardized workflow following the criteria of the gnathological school of Vienna of Prof. Rudolf Slavicek.

Click here to read. Enjoy!

Start Reading: BOND | SPECIAL EDITION | 6/2021

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BOND | VOLUME 7 | 10/2020

Technological progress has enabled the development of products with a wide range of applications, as well as resulting in simplified procedures. These products offer multiple benefits for the user; less laborious procedures come to mind, not to mention fewer steps and faster processing. The direct result is a reduced potential for the sort of procedural mistakes that can lead to serious consequences. As for stock levels, far fewer products are now required to achieve the envisaged end result. This means that the risk of stored products exceeding their best-before dates is greatly reduced, leading to cost savings as well as contributing to shrinking the waste mountain.

Under the umbrella name Universal Excellence, Kuraray Noritake Dental Inc's product range includes a well-balanced selection of universal bonding and cementing products, making it possible for dentists to perform a wide range of treatments with only a limited product range.

CLEARFIL™ Universal Bond Quick is the basis for adhesive treatments; a one-step universal bonding that can be used, at the dentist's discretion, as a self-etching or fully-etched bonding option or as a combination of selective enamel etching. Rapid Bond Technology is used for this bonding, which also contains fluoride. This technological development makes it possible to realise maximum penetration in tooth tissue, followed by hydrophobic sealing after light-curing. The original MDP monomer constitutes the backbone of CLEARFIL™ Universal Bond Quick, as it does in our other bonding systems.

The recently introduced CLEARFIL MAJESTY™ ES-2 Universal composite is truly a game changer. This material is universal both in terms of indication spectrum and colour adaptation. CLEARFIL MAJESTY™ ES-2 Universal may not be the only composite in this relatively new segment, but it is by far the most forgiving. This is due to the meticulously calculated amount of refractory fillers, or so-called light diffusion fillers, in a composite of optimum translucency. The composite blends effortlessly with the colour of the teeth without the need for additional opaque composites in small or large anterior or posterior restorations.

CLEARFIL MAJESTY™ ES Flow is a flowable composite available in three levels of flowability. This flowable integrates seamlessly with the Universal Excellence concept, thanks to its wide range of indications. The unparalleled Kuraray silane technology and the specific resin used provide that CLEARFIL MAJESTY™ ES Flow is not only flowable, but also strong; in fact, this flowable is actually stronger than most paste composites. It is also a genuine pleasure to work with. Unlike other flowables, CLEARFIL MAJESTY™ ES Flow can be applied and manipulated easily because it does not stick to the application needle or instrument.

Wouldn’t it be good to have adhesive resin cements without the need for additional primers? This is now possible with PANAVIA™ SA Cement Universal. Only one product needed to bond to tooth tissue and to most prosthetic materials. It will even bond to glass-based ceramics such as lithium disilicate without the use of a separate silane primer. That is because – in addition to MDP – PANAVIA™ SA Cement Universal includes the unique, long carbon chain silane (LCSi) also used in CLEARFIL MAJESTY™ ES Flow. How universal can a product be?

Finally, we would like to highlight KATANA™ Cleaner, a universal cleaning agent for both intra-oral and extra-oral use. Clean, decontaminated surfaces are the most effective basis for adhesive procedures, and because KATANA™ Cleaner is based on MDP, it is also fully compatible with our bonding and adhesive/cementing products.

You can rely on Universal Excellence both in terms of providing the very best treatments in your practice, and to avoid the holding of unnecessary stock and the risk of being confronted with unused products that have exceeded their best-before date.

Dr Max Andrup, a 2010 graduate of Umeå University, currently runs a private practice in the city of Hudiksvall in Sweden, where he maintains a passion for restorative dentistry with a biomimetic approach. In this interview, he discusses the future of restorative dentistry and explains why he relies on Kuraray Noritake Dental’s products for his daily workflow.

Dr Andrup, could you please tell us a bit about your dental career to this point?

For the first few years of my career, I pursued a residency as an oral and maxillofacial surgeon. For various reasons, I ended up buying my own practice instead, and I couldn’t be happier with that decision! It allows me to take my time with patients and focus on delivering high-quality treatment together with co-workers with whom I really enjoy working.

How did your passion for restorative dentistry develop?

I have always enjoyed bringing patients’ dentition back to a functional and aesthetic state. I’m not sure why exactly, but I started looking for dental accounts on social media to broaden my horizons and to see how others solved challenging clinical situations. This was a turning point for my career, as I found so much inspiration and learnt a great deal from what others shared.

Do you have a dental philosophy? If so, what are its guiding principles?

Knowing that many people don’t really like going to the dentist, my goal in my practice has always been not just to provide excellent oral care but also to offer a comfortable and relaxing experience. My ultimate goal is that no patient should feel anxious about his or her visit. The patients don’t necessarily have to look forward to their visits, but they shouldn’t be something over which they lose sleep.

When were you first introduced to Kuraray Noritake Dental's portfolio of products?

About three years ago, I found these Instagram accounts talking about gold standard adhesives and biomimetic restorative dentistry. This piqued my interest, and I started to read many scientific papers in order to understand why some adhesives worked better than others, why certain composites are preferable when replacing deep dentine, and so on. Products from one particular company kept coming up: Kuraray Noritake Dental. I had never worked with their products before but, convinced as a result of what I’d read and seen, I ordered a starter pack with CLEARFIL™ SE Protect adhesive, CLEARFIL MAJESTY™ Flow and CLEARFIL™ AP-X and haven’t looked back since!

Which Kuraray Noritake Dental products do you use on a daily basis in your workflow and why?

The one product I couldn’t survive without is the CLEARFIL™ SE Protect adhesive. It brings a level of research and clinical backing that gives me a feeling of confidence when conducting restorative dentistry. It contains the MDPB monomer, which results in lower levels of bond degradation. If you want to achieve a bond strength to dentine in the range of 40-50 MPa* it all starts with the right dentine bonding agent, and CLEARFIL™ SE Protect is just that.

*depending on testing method

What do you think will be trends, or points of emphasis, in restorative dentistry moving forward?

Unfortunately, I believe that the trend in the field of dentistry will continue to move towards simplification regarding bulk-fill restoratives and one-step adhesives. I can understand why-simple procedures are faster, and many clinicians have very limited time. The truth is, however, that developing a strong bond to dentine takes time, and you need to have an understanding of how the materials work to make the bond last.

In the past few years, new technologies have emerged that make it easier to study what happens in the bottom of a cavity when placing bulk-fill restoratives and, as expected, the contraction stress from the polymerisation process forms gaps in the cavity floor. This results in postoperative sensitivity and eventually a degraded bond. Getting a strong and durable bond to dentine starts with a gold standard adhesive like CLEARFIL™ SE Protect, but if you don’t respect the hybrid layer and place bulk fill over it, it will most likely fail.

By Prof. Dr. Florian Beuer

Zirconia has been the most popular all-ceramic material in dentistry for more than two decades. While the earlier generations of zirconia had to be veneered with porcelain to achieve acceptable aesthetics, recent developments showed higher translucency, allowing them to be used as full-contour restorations with partial veneering on the buccal aspects. However, the higher translucency was paid off by reduced mechanical stability.

In the past, we had to decide whether we want high stability or high translucency. With the introduction of the new KATANA™ Zirconia YML, both characteristics are combined in one disc. Analogue to previous multi-layer materials, the graded translucency is now combined with graded mechanical strength. The three apical layers (body 1 to body 3) consist of high strength zirconia with a flexural strength of 1000 MPa, while the enamel layer shows a flexural strength of 750 MPa. Thanks to this combination, aesthetics can be achieved much easier with higher buffers for mechanical stress. On the other hand, there is the potential to reduce thickness of the restoration and save tooth tissue during preparation.

At the KATANA™ Zirconia YML symposium (www.kuraraysymposium.info) on July 3^rd, we will look at the developments of zirconia in the last years and point out the significance of monolithic restorations, their strengths and the crucial issues in the treatment protocol. Join us!

Dentist:

PROF. DR. FLORIAN BEUER

Professor and Chair, Department of Prosthodontics, Geriatric Dentistry and Craniomandibular Disorders, Charité – Universitätsmedizin Berlin, Germany.

The fact that different zirconia materials are used depending on the indication is both a blessing and a curse: Blessing because it allows dental technicians to achieve the best possible outcomes in every situation, and curse because the approach requires a extensive inventory and a lot of decisions. For those who prefer to take a more efficient route without compromising the outcomes, KATANA™ Zirconia YML is the new go-to solution. With its strong core and translucent outer layer, this new generation of multi-layered zirconia offers the properties needed for a broad indication range and easily obtained aesthetics.

KATANA™ Zirconia YML is the reinvention of the original multi-layer technology developed by Kuraray Noritake Dental Inc. (Kuraray Noritake Dental) more than a decade ago. It features new raw materials of different yttria concentrations integrated into the well-liked four-layer colour structure. The result is a disc with a well-balanced combination of chroma, translucency and flexural strength gradation.

As all body layers have a flexural strength of at least 1,000 MPa, the new zirconia fulfills the requirements for a broad range of indications even including monolithic long-span restorations. With its proven colour gradient and super-high translucency enamel layer, the aesthetic potiential is so high that it is often sufficient to opt for a monolithic design of the desired restorations and a time-saving finishing procedure such as polishing or ultra-micro layering with liquid ceramics (e.g. CERABIEN™ ZR FC Paste Stain).

The different layers in the blank are perfectly adjusted to each other through an in-house production procedure which ensures easy positioning of the restorations within the blank, a seamless multi-layer structure required for flawless aesthetics, a precise fit and predictable long-term behaviour.

The advanced fabrication and material composition comes with another advantage: A 54-minute high-speed sintering procedure is available for single-tooth restorations and bridges with up to three units. The optical and mechanical properties of the restorations are comparable to those after the alternative 90-minute or seven-hour sintering cycle.

KATANA™ Zirconia YML will be available July 1^st 2021. To celebrate the launch of the new member to our KATANA™ Zirconia family, we invite you to join us for a virtual kick-off symposium on July 3^rd, 2021 at 10:00 CET. We will show you how aesthetic outcomes are achieved with minimal effort, how design flexibility puts you in control and how the pace of procedures is accelerated without compromising quality.

Registration and further information: www.kuraraysymposium.info

Download brochure:

Discover the next step in the evolution of multi-layered zirconia!

Let us introduce you to KATANA™ Zirconia YML, the next step in the evolution of multi-layered zirconia! The material of superlatives will take center stage at the KATANA™ Zirconia YML Virtual Kick-Off Symposium on July 3, 2021. Renowned experts from the scientific and practical field will share important facts and first-hand information on the unique allrounder and its ability to empower dental laboratories.

Celebrating the launch of the new member to our KATANA™ Zirconia family, we will show you how aesthetic outcomes are achieved with minimal effort, how design flexibility puts you in control and how the pace of procedures is accelerated without compromising quality.

Hence, participation is highly recommended for everyone striving for more: more safety, more reliability, more simplicity and, ultimately, more time.

Registration and further information: www.kuraraysymposium.info

Interview with Peter Schouten, Technical Manager, Kuraray Europe Benelux

PRECISION - STRENGTH - POLISHABILITY

When creating KATANA™ AVENCIA™ Block for CAD/CAM, our goal was to develop a block that would be easy to grind while delivering a smooth surface. Of course, its mechanical properties had to be first-rate, and we aimed for excellent gloss retention. Finally, it goes without saying that KATANA™ AVENCIA™ Block restorations had to be durable as well as being suitable for adhesive cementing.

Existing hybrid ceramic blocks on the market (except for VITA™ Enamic) are produced in the same way as direct dental filling composites, namely, silanized filler mixed with synthetic resin. The composite is then formed into a block or a mold and polymerised. The disadvantages are a non-uniform distribution of the filler particles and an increased risk of trapped air which can result in voids. Instead, KATANA™ AVENCIA™ Block uses the unique Filler Press and Monomer Infiltration method, developed by Koichi Okada et al. The treatment of the filler is what makes this method so unique.

Nano-sized silica fillers pre-treated with silane combined with nano-sized alumina fillers are densely compressed into a block which is subsequently impregnated with resin. Finally, the blocks are polymerized by heat to achieve a maximized degree of polymerization. Blocks manufactured in this way have a dense, homogenous and virtually void-free structure.

SEM photos show the microstructure of KATANA™ AVENCIA™ Block, in a comparison with other materials. KATANA™ AVENCIA™ Block is filled densely and uniformly with only nano-sized filler.

Smooth

Owing to the high filler content with filler particles of up to a maximum of 40 μm, KATANA™ AVENCIA™ Block is not only strong but also extremely easy to grind. Thanks to smooth result the next step - polishing - is simplicity itself.

Strong

The KATANA™ AVENCIA™ Block is yet another example of how we have fully exploited our knowledge and expertise in the silanisation of fillers. The nano-sized, optimally silanised silica fillers establish tight connection between silica and resin-matrix. This is essential when aiming to achieve strong and stable prosthetics.

*Not a trademark of Kuraray Noritake Dental Inc.
** Test Condition: Toothbrush wear test using tooth paste. Load: 250 g.
Source: Kuraray Noritake Dental Inc.

Polishability

The dense, homogenous, and void free structure of KATANA™ AVENCIA™ Block is the reason that the high gloss easily achieved with polishing only will be long-lasting. KATANA™ AVENCIA™ Block shows virtually no reduction of gloss after tens of thousands of brushing movements in the toothbrush test.

For optimum, long-lasting and durable results, it goes without saying that KATANA™ AVENCIA™ Block restorations should be affixed with one of the products from the PANAVIA™ family.

Wouldn’t it be great to have a single dental material indicated for the treatment of all kinds of hypersensitivities? A product that effectively and durably occludes exposed dentinal tubules caused by gingival recession, dental erosion or excessive toothbrushing, but also works in the context of professional tooth cleaning, scaling and root planning, tooth whitening or restorative procedures? The fact that Kuraray Noritake Dental Inc.’s TEETHMATE™ DESENSITIZER is ideally suited for all those indications by providing lasting hypersensitivity relief is surely one of the reasons for its winning of a Dental Advisor award for the seventh consecutive year.

Designed to crystallize hydroxyapatite (HAp) from the ground up, TEETHMATE™ DESENSITIZER reliably seals exposed dentinal tubules and enamel cracks.

Consisting of natural calcium and phosphate, the product may even be applied to freshly prepared tooth structure without negatively affecting the bond strength of subsequently utilized dental adhesives or cements.

The consultants of the Dental Advisor conducted a six-month clinical study to be able to evaluate the performance of TEETHMATE™ DESENSITIZER. They selected 27 patients with hypersensitivity issues in their dental practices. Thermal testing with cold air was used to identify the affected teeth, 54 of which were included in the evaluation. For the initial assessment, patients were asked to evaluate their level and frequency of hypersensitivity per tooth on a five-point scale (1 = severe, persistent sensitivity to 5 = no sensitivity). Subsequently, TEETHMATE™ DESENSITIZER was applied according to the instructions for use. Sensitivity was evaluated again immediately after the treatment and six months later. At baseline, 91 percent of the patients stated that they had no or only mild, sporadic sensitivity, which was still the case for 85 percent after six months. This indicates that the product is very effective in providing immediate and even long-term hypersensitivity relief.

Hence, it is not surprising that TEETHMATE™ DESENSITIZER has been among the winners of the Dental Advisor’s Top Product Award every year between 2015 and 2021.

Study results that confirm the material’s effectiveness in reducing pre- and post-operative sensitivity in the context of tooth whitening¹ and indirect restoration procedures² are also available, so that users can count on a reliable performance in a wide range of indications.

References

1. Mehta D, Jyothi S, Moogi P, Finger WJ, Sasaki K. Novel treatment of in-office tooth bleaching sensitivity: A randomized, placebo-controlled clinical study. J Esthet Restor Dent. 2018 May;30(3):254-258.
2. Shetty R, Bhat AN, Mehta D, Finger WJ. Effect of a Calcium Phosphate Desensitizer on Pre- and Postcementation Sensitivity of Teeth Prepared for Full-Coverage Restorations: A Randomized, Placebo-Controlled Clinical Study. Int J Prosthodont. 2017 Jan/Feb;30(1):38-42.