429 Too Many Requests

The use of highly translucent, gradient pre-shaded zirconia brings more efficiency into the dental laboratory. Due to the advanced properties of the materials, e.g. from the KATANA™ Zirconia Multi-Layered Series, true-to-life restorations may be created without any or with only a small vestibular layer of veneering porcelain. This saves a lot of time usually required for manual work around steps in the veneering of zirconia frameworks. At the same time, this also allows for a reduced wall thickness, beneficial in the context of minimally invasive dentistry.

In order to leverage the high aesthetic potential and balanced mechanical properties of these types of zirconia, however, it is essential that the restorations are processed under ideal conditions. The most advanced materials with the highest translucency are particularly sensitive to contamination during and after wet milling, contamination of the furnace chamber, and temperature variations during sintering. Possible undesirable effects include a grayish appearance of the restorations and low chroma, green, yellow, blue or gray traces in the restorations, white spots on the surface and variations in colour and translucency.

If carried out on a regular basis, the following measures will effectively eliminate these effects. Hence, they will support users in ensuring consistently beautiful results.

Optimizing the milling process

Blue or gray traces visible in the final restoration are usually the result of contamination of the cooling water with extrinsic particles in the context of wet milling, (which is usually conducted in chairside procedures). In most cases, silica particles left over from the processing of glass or silicate ceramics with the same milling unit are the root of the problem. The effect is easily avoided by thorough cleaning of the milling chamber, the water tank and the filter insert of the milling machine every time a different material needs to be processed. Another solution is dry instead of wet milling, which offers additional benefits such as shorter processing time and better quality edges and surfaces.

Decontamination of the furnace chamber

In general, the chamber of the sintering furnace should be cleaned before sintering. Important measures include the removal of dust inside the sintering chamber and cleaning of the heating elements, both done with a soft brush. The use of compressed air is contraindicated.

Unwanted optical effects that occur on restorations due to contamination of the sintering chamber include white spots on the restoration surface, a blue-grayish appearance and low chroma, and green or yellow traces in the material. White spots on a restoration surface are usually indicators of contaminated alumina sintering beads or the use of the wrong instruments for surface modification and sprue removal. The effect is avoidable through a monthly or even more frequent replacement of the sintering beads (as soon as they show any signs of discoloration) as well as the exclusive use of fine-grid diamond instruments for adjustments prior to sintering.

Alumina sintering beads may be the cause of white spots on a restoration surface if not replaced on a regular basis.

The blue-grayish appearance and low chroma may be attributed to mineral residues from dipping liquids in the chamber. They are effectively removed with the aid of a decontamination program to be selected in the furnace menu, which is run after inserting several residual pieces of a highly translucent, white zirconia blank. As soon as the decontamination cycle is completed, the chromatic intensity of the residual blank parts indicates whether a second cycle is required. In order to prevent the occurrence of a grayish appearance in new restorations, it is recommended to perform a decontamination program at least once per month.

Pieces of a white zirconia blank left over after milling.

MoSi₂ heating elements: Regeneration needed

If a restoration appears to be green or yellowish, it is most likely that the furnace is equipped with aging molybdenum disilicide (MoSi₂) heating elements in need of regeneration or replacement. The inner part of the elements is made of molybdenum (Mo), which is usually covered by a protective layer of silica (SiO₂). This layer is naturally built up during sintering at a temperature range between 1,000 and 1,600°C. As the thickness of the layer grows, its intrinsic residual compressive stress increases. This stress, as well as possible extrinsic influences, e.g. originating from acidic dipping liquids, may finally lead to cracks and a breakup of the protective layer. Once damaged, the molybdenum core is exposed. At a low temperature range of 400 to 600°C, the molybdenum reacts with oxygen in the sintering chamber, a process referred to as pest oxidation. The resulting molybdenum oxide (MoO₃), together with ions or metal oxides from colouring agents, is responsible for the green-yellowish discoloration on the surface of the restorations.

Restorations displaying greenish surface pigmentation.

Molybdenum disilicide heating element with a protective silica layer bursting off, leading to pest oxidation and the contamination of elements in the sintering chamber.

Regeneration firing, which involves a rapid heating rate and a long firing phase at approx. 1,450°C, aims at regenerating the layer of silica. This measure, however, works only a limited number of times, as a repeated process of pest oxidation and regeneration leads to aging of the heating element itself. Hence, it will ultimately lead to the need for replacement. The whole issue of pest oxidation may be effectively avoided by the use of a furnace with silicon carbide heating elements, which are highly aging-resistant and do not cause any discoloration. A positive side effect is that these types of heating elements deliver more constant temperatures.

Temperature control

Variations in translucency or chroma and pigmentation of restoration surfaces are often due to deviations of the actual sintering temperatures from the recommended temperature curve. The only way to solve this issue is temperature calibration. This measure is not only a prerequisite for aesthetic results, but also has a decisive impact on the mechanical properties of the restorations: if the maximum temperatures are too high, for example, the flexural strength of the zirconia materials may be expected to decrease¹.

Effect of temperature differences during sintering on restorations made of KATANA™ Zirconia UTML: The restorations were sintered at the same nominal temperatures in three different furnaces!

Temperature control is usually carried out with the aid of TempTABs or PTCRs (process temperature control rings). They are placed into the furnace on a sintering tray and typically processed by running a calibration cycle. After sintering, the tab or ring diameter is determined. As TempTABs and PCTRs exhibit controlled shrinkage, it is possible to calculate the actual sintering temperature based on the measured diameter. A conversion table supports the user in determining the deviation between the temperature actually reached and the temperature displayed on the furnace. Subsequently, the values displayed on the furnace are adjusted if necessary.

TempTAB on a sintering tray with restorations ready for sintering.

General recommendations

In order to set the stage for brilliant aesthetics and ideal properties of zirconia restorations, it is essential to ensure optimal processing conditions. Instead of troubleshooting carried out whenever discoloration appears after sintering, it is advisable to take the following actions on a regular basis as preventive measures:

• Cleaning of the milling machine’s water tank every time before starting to mill (wet milling only)
• Strict adherence to the sintering protocols recommended by the material manufacturer
• Removal of the dust from the sintering chamber and heating elements with a soft brush before each use
• Replacement of the alumina sintering beads whenever they show signs of discoloration (at least once per month)
• Exclusive use of fine-grid diamond instruments for sprue-removal and pre-sintering adjustments
• If possible: Use of furnace with silicon carbide heating elements
• Furnaces with molybdenum disilicide heating elements require constant visual control and regular regeneration cycles
• Running of a decontamination program with decontaminating powder or white zirconia residues (y-TZP) at least once per month
• Temperature control and calibration at least once per month

With these simple measures, it is possible to maximise the full potential of KATANA™ Zirconia Multi-Layered Series from Kuraray Noritake.

References
¹ Stawarczyk, B., Özcan, M., Hallmann, L. et al. The effect of zirconia sintering temperature on flexural strength, grain size, and contrast ratio. Clin Oral Invest 17, 269–274 (2013).

Dentistry is currently experiencing an interesting evolution. While dentists are becoming increasingly specialised, the demand for products that can be used for all indications continues to grow. These systems and materials are part of a universal trend in dentistry—a trend that Kuraray Noritake Dental is extremely well suited to accommodate.

Advancing adhesive dentistry

As the technology has developed, dental adhesives have progressed from no-etching to total-etching and then self-etching systems. In 1978, Kuraray Noritake Dental introduced CLEARFIL™ BOND SYSTEM-F, the world’s first total-etching adhesive system. More than four decades later, the company is still setting standards with CLEARFIL™ Universal Bond Quick, a one-step dental bonding agent that can be used in total-etching, self-etching and selective-etching modes.

Combining Kuraray’s original MDP monomer with hydrophilic amide monomers, CLEARFIL™ Universal Bond Quick is designed to be less technique-sensitive than other one-step solutions and has been proved scientifically to deliver stronger, more stable bonds.

It is not just bonding agents that are becoming universally applicable either. A dental cement like Kuraray Noritake’s PANAVIA™ SA Cement Universal builds upon the success of previous generations of PANAVIA™ to deliver optimal bonding to dental tissue as well as to metal and zirconia materials. This self-adhesive resin cement always requires the same procedure, even when bonding porcelain, lithium disilicate and composites, without the need for a primer. The reason? It’s the addition of a unique long carbon chain silane.

Universal composites and cleaners

The silane technology behind PANAVIA™ SA Cement Universal can also be found in CLEARFIL MAJESTY™ ES Flow, a universal flowable composite suitable for all cavity classes. Its small, durable filler particles help to ensure excellent flexural and mechanical strength, while special cluster fillers provide a light diffusion effect similar to that of natural teeth. Creating aesthetically natural and reliable restorations is easier than ever with CLEARFIL MAJESTY™ ES Flow.

As the latest addition to the CLEARFIL MAJESTY™ ES series, CLEARFIL MAJESTY ES-2 Universal offers a smart and easy-to-use system that will work for the vast majority of your daily cases. Its light-cure, radiopaque restorative material which provides accurate color matching, high polishability and excellent physical properties, makes the product ideal for both anterior and posterior restorations. What makes this Universal series truly special is that the shades cover all shades of the VITA classical A1-D3 shade standard with a limited number of syringes/PLTs depending on the cavity class. If you opt for CLEARFIL MAJESTY™ ES-2 Universal, just a few shades will do the trick.

And when considering Kuraray Noritake’s forays into universal solutions, let us not forget the new KATANA™ Cleaner, a non-abrasive cleaner that, unlike other options on the market, can be used both intra- and extra-orally. Backed by extensive scientific research, the KATANA™ Cleaner comes with a single-handed delivery cap and an extremely straightforward method of application: simply apply with a rubbing motion for at least 10 seconds, rinse with water and air-dry before cementation.

Making dentistry more streamlined

The modern dental practice is often multidisciplinary in its nature, which can result in the need to store many more products than there might be space for. Through these universal products and others, Kuraray Noritake is aiming to make dentistry simpler and more efficient.

At Kuraray Noritake Dental Inc. we are proud that our products are being developed using innovative technologies, paying attention to detail and keeping in mind the needs of our customers.

We are committed to offering outstanding products that provide dental professionals with the flexibility for self-expression and creativity, adding value and delivering superb aesthetic results to each and every procedure.

Usability, simplicity and, of course, quality always in mind - providing dental professionals with materials that will make their daily practice stress free.

As a prove that our products meet the needs of dentists and lab technicians alike, we are happy to share with you the EC Certificates of Full Quality Assurance System that we have received from The Notified Body.  Those can be downloaded below.

Chairside products

Labside products

When it was first introduced to restorative dentistry in the early 2000s, zirconia was an opaque, unnatural-looking substance with a chalk-like whiteness. Two decades later, technological and material advances have meant that zirconia is now a highly aesthetic and durable ceramic solution for a variety of procedures. Leading the way is Kuraray Noritake Dental’s KATANA™ Zirconia series, which can now be integrated at every step of the restorative workflow.

The pioneering nature of KATANA™ Zirconia

Key reasons for zirconia’s improvements as a dental material are continued innovations in the powder that forms the basis of the discs. While a majority of dental zirconia manufacturers rely on a single shared provider of powder, Kuraray Noritake’s zirconia materials are unique in that they are produced in an end-to-end in-house process. From the proprietary powder technology through to disc pressing and pre-sintering, KATANA™ Zirconia is produced to ensure unparalleled purity and unmatched quality.

Multilayered technology

Three of the four types of KATANA™ Zirconia—UTML, STML and HTML—incorporate Kuraray Noritake’s original multilayered build-up technology. This innovative four-layer structure faithfully replicates the translucency and colour gradation of natural dentition, resulting in an eye-pleasing final restoration. Furthermore, each member of the KATANA™ Zirconia series possesses different translucency and mechanical properties, allowing clinicians to cover a wide range of anterior and posterior restorations.

A zirconia series embedded in a system of products

Thanks to Kuraray Noritake’s emphasis on research and development, the KATANA™ Zirconia family is embedded in a complete system of products for polishing, staining, glazing, porcelain veneering and cementation in order to deliver outstanding treatment outcomes.

CERABIEN™ ZR FC Paste Stain allows for the easy characterisation of full-contour zirconia restorations. Available in 27 different shades, it delivers an extremely controllable transparency that enables the creation of highly aesthetic restorations.

When cementing a zirconia restoration during the trial fitting stage, the new KATANA™ Cleaner will surely come in handy. This non-abrasive universal cleaner from Kuraray Noritake helps to remove contamination, thereby delivering the bond strength patients deserve. Its relatively low pH value of 4.5 also means that, unlike other dental cleaners, it can be used both intra-orally and extra-orally.

Of course, when finally cementing the restoration, the dentist needs to be confident that the cementation will be both reliable and durable. PANAVIA™ V5 is Kuraray Noritake’s strongest cement yet and offers unrivalled procedural simplicity and predictability. This amine-free paste is available in five different shades that have been scientifically demonstrated to exhibit less post-polymerisation colour variance than amine-based cements. For aesthetic and stable cementation, PANAVIA™ V5 is the best option.

It is clear that, with the translucent KATANA™ Zirconia series and these associated products, Kuraray Noritake has established a fully integrated system that can work for almost any prosthetic workflow. KATANA™ Zirconia is key to durable metal-free restorations.

Phosphoric acid is not only used for etching enamel and dentin surfaces within dental bonding procedures, but also frequently as an intra- and extra-oral cleaning agent for tooth structure and dental restorations. But is phosphoric acid always the right choice?

Direct Restorations

Many bonding procedures are performed using self-etch adhesive systems. When applied to the prepared tooth surface, the acidic monomers in the primer and/or the bond partially remove and modify the smear layer, resulting in a thin hybrid layer. A substantial amount of hydroxyapatite crystals remain on the slightly etched surface, enabling both chemical and mechanical adhesion between the adhesive and the dental tissue. If the bonding surface in the cavity is contaminated e.g. with blood or saliva, and phosphoric acid is applied for cleaning and decontamination, it etches the tooth structure, too, resulting in the removal of HAp. This will prevent the desired chemical adhesion, between the bonding system and the tooth, which may lead to compromised bond strength. Hence, cleaning with phosphoric acid may have a negative effect in this context and cannot be recommended.

Great cleaning results with no negative effect on the performance of the dental adhesive are obtained with the universal cleaning solution KATANA™ Cleaner. It contains an MDP salt of triethanolamine (MDP-TEA), as well as 'free' MDP. With a pH of 4.5, KATANA™ Cleaner is essentially neutral, meaning that, unlike phosphoric acid, it does not remove hydroxyapatite from the tooth. However, it does still effectively eliminate any saliva and/or blood contamination.

Indirect Restorations

For materials containing glass, such as lithium disilicate and feldspathic porcelain, phosphoric acid is a tried-and-tested agent for removing contamination, such as deposits produced when etching these materials with hydrofluoric acid. However, routine use of phosphoric acid to remove contamination from indirect restorations may not be wise. In fact, its use on zirconia is not recommendable, as it could inhibit the desired chemical adhesion of phosphate monomers in the bonding agent to the surface of the zirconia restoration.

When cementing prosthetics using self-adhesive resin cements like PANAVIA™ SA Cement Universal or cements that use self-etching primers (e.g. PANAVIA™ F2.0 or PANAVIA™ V5), the use of phosphoric acid on dentin is not recommended for the same reasons as in the case of direct restorations.

No pitfalls, no restrictions

Unlike 35% phosphoric acid, KATANA™ Cleaner is a product that cleans reliably without inducing negative side effects – independent of the type of tooth structure, kind of restorative material and planned bonding procedure. Hence, it is a universal cleaning solution that allows you to streamline your procedures.

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

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.

As co-editor-in-chief of the Journal of Adhesive Dentistry, Prof. Bart Van Meerbeek is one of the most respected authorities on the topic of dental bonding agents. Here, he discusses how they have advanced over the last three decades and what the future of adhesive dentistry might look like.

Prof. Van Meerbeek, how have bonding agents changed and advanced since you first began studying them?

I believe that the great progress dental adhesive technology has undergone in the last 30 years, and the progress in bonding agents in particular, has had a great impact on the field of dentistry and particularly on restorative dentistry, of course. Many of the current restorative dental procedures make use of adhesive materials and techniques and have advanced greatly compared with when I wrote my dissertation more than two decades ago on the topic of adhesion to dentine. Adhesion to enamel is, of course, relatively easy to achieve in comparison with adhesion to dentine, and when I first started researching this topic, I was limited to conducting clinical trials in which we were confronted with a relatively high number of restoration losses in the short term. I was lucky to have been able to witness first-hand the fast advancements dental bonding has made, having conducted research in this field now for nearly 30 years.

At a certain point, the research community started to realise that there is a smear layer in-between, which is created through cavity preparation, and that this layer interferes with bonding. If you want to achieve successful micromechanical and chemical bonding to the substrate, you first need to do something with this smear layer.

After this, we entered the era of conditioners and primers. In the past, the restorative community had been a little bit afraid of using phosphoric acid owing to its potential for pulp irritation. More and more, however, dental professionals began to use etchants with this chemical in them, as well as primers that effectively promoted bonding between the adhesive resin and dentine. While having achieved excellent bonding performance with multistep adhesives in the laboratory, as was later confirmed in clinical studies, further design and development of adhesive materials next focused on simplification and shortening of bonding procedures.

Out of this, two kinds of adhesives, making use essentially of two different bonding modes, arose: the etch-and-rinse adhesives and the self-etch, or etch-and-dry, adhesives. The newest generation of universal adhesives now enables dental practitioners to choose which of the two bonding modes to apply with one single adhesive formulation.

What advantages do bonded restorations offer over more traditional methods?

Bonded restorations are minimally invasive—the dentist doesn’t have to remove non-diseased tissue to create undercuts to keep the restoration in place, allowing for a more conservative approach. Keeping as much enamel as possible should be a goal of any restorative procedure, as it is simply the best tissue to bond to. Although bonding to dentine has always remained more challenging and has actually slowed down our adhesive endeavours for a long time, adhesively restoring teeth, involving also effective bonding to dentine, can today be achieved in a reliable, predictable and durable way.

Along with highly successful implantology to replace missing teeth, lessening the need for bridges, solitary tooth restorations have substantially increased in number. Bonding promoted the additional shift from conventional tissue-invasive crowns to tissue-preserving partial tooth restorations, as modern adhesives can hold such partial restorations in place on rather flat and even non-retentive surfaces. In addition, bonding procedures allow for more natural-appearing restorations to be achieved by techniques to adhesively lute aesthetic restorations made of glass-ceramics and even the strong zirconia ceramics that no longer can be considered non-bondable.

What is your opinion regarding the current generation of universal adhesive solutions?

I think that this generation is very good, but that they are still not always as good as the more traditional gold standard two-step self-etch and three-step etch-and-rinse adhesives when it comes to their intrinsic bonding potential to dental tissue. However, I do see it as a positive that many of these universal adhesives integrate the MDP monomer, which should be considered to be one of the best functional monomers available today, though it needs to be present at a high concentration and purity level.

The MDP monomer is, generally speaking, excellent at bonding to zirconia as well. When it comes to bonding to different kinds of ceramic as well as resin-based composite restorative materials, it is always helpful to know which universal adhesives contain silane and are claimed to no longer need further treatment of the restoration. This has the advantages of lower technique sensitivity and fewer procedural steps—provided that it does, of course, work. There is current scientific evidence that the silane incorporated in today’s acidic aqueous universal adhesives is, however, insufficiently stable. Fortunately, research is underway to develop new universal adhesives that contain other silanes with higher stability in water at higher acidity.

Overall, I believe that a restoration primer that contains a high concentration of silane along with the MDP monomer is still more effective than many universal adhesives for bonding to restorative materials, since these universal adhesives can contain many other ingredients that create a kind of competition within the material to reach and interact with the substrate surface, leading to lesser bonds.

Another shortcoming of universal adhesives is their thin film thickness and relatively high hydrophilicity, promoting water uptake and hence making them sensitive to hydrolytic degradation. In this light, it’s important to note that, when a viscous and hydrophobic flowable composite is applied on top of a universal adhesive, it can make up for this somewhat and allow for durable bonding to take place.

Is the MDP monomer crucial to the ultimate success of universal adhesives? Are there other factors that can influence this?

Well, it’s very clear that the MDP monomer is one of the most effective monomers available, given its primary chemical binding potential to hydroxyapatite. However, there are significant differences in the MDP monomer purity and concentration levels between these products, factors that are affected by whether or not the monomer is synthesised by the company itself or whether this process is outsourced. Essentially, a universal adhesive that contains a high concentration of very pure MDP monomer should perform the best.

Are there any specific advantages that a self-etch adhesive possesses?

The biggest advantage is that it doesn’t remove all hydroxyapatite and minerals present in dentine and so keeps the weaker dentinal collagen protected. Phosphoric-acid etching results in relatively deep and complete demineralisation with collagen exposure, making the bond more prone to degradation. Partially maintaining minerals around collagen using a mild self-etch adhesive additionally allows for strong ionic bond formation to take place when the adhesive in particular contains the functional monomer MDP. In addition, one should be aware that, while chemical binding doesn’t necessarily lead to higher bond strength, it can create better long-term bond durability.

What do you see as the next step in adhesive dentistry?

One possibility is to reduce the number of steps in the adhesion process with the final goal of having self-adhering restorative materials. There have been developments in this direction, including studies and commercial products, though the products haven’t always proved to be very effective and their bond durability is unclear. Now, however, there are newer materials coming to market with claims that they can be used with no pretreatment. Their clinical effectiveness, nevertheless, still needs to be proved and guaranteed before such self-adhering restorative materials could be used as true amalgam alternatives in routine dental practice.

Another possibility, and current R & D hype, is the development of bioactive adhesives. Many dental researchers and many companies want adhesives not only to deliver good bonding performance but also to have certain therapeutic benefits. What exactly a bioactive adhesive is depends on who you’re talking to. Some researchers believe that they should have antibacterial qualities, whereas others state that remineralisation of dentine and pulpal cell interaction are needed to qualify for the term “bioactive”. We certainly need to investigate whether we can give these materials these additional properties, but on one condition: that the adhesive material does not lose any of its original bonding abilities. That, in my opinion, is the biggest challenge for the future of adhesive dentistry.

Produkts CLEARFIL MAJESTY^TM ES Flow ir ieguvis Dental Advisor galveno balvu jau piecus gadus pēc kārtas un tagad ir pieejams ar trīs veidu plūsmām. Tādējādi tiek piedāvāta pavisam jauna līmeņa daudzpusīga darbība, lai zobārstniecības speciālists varētu ātrāk un ērtāk panākt vēlamo restaurācijas rezultātu.

CLEARFIL MAJESTY^TM ES Flow universālais plūstošais kompozītmateriāls ir jaunākais uzņēmuma Kuraray Noritake Dental produkts. Šis uzņēmums ir izpelnījies atzinību visā pasaulē, jo ir apliecinājis savas zināšanas par restaurācijai nepieciešamajiem materiāliem. Uzņēmums Kuraray Noritake Dental izmantoja materiāla CLEARFIL MAJESTY^TM Flow panākumus, lai izstrādātu īpaši uzlabotu produktu, kas nodrošina restaurāciju, reparāciju un cementēšanu bez citu kompozītmateriālu izmantošanas.

Pateicoties Kuraray Noritake Dental patentētajam silāna savienojošajam līdzeklim, kas izmantots kompozītmateriālam CLEARFIL MAJESTY^TM ES FLOW, gan submikronu, gan nanoklasteru pildviela tiek stabili piesaistīta kompozītmateriālam. Līdz ar to materiālam CLEARFIL MAJESTY^TM ES FLOW ir arī lielāka pildvielas noslodze, saglabājot produkta plūstamību. Estētiku bagātina nanoklasteri jeb gaismas difūzijas pildviela, kas gādā par kompozītmateriāla nemanāmu iekļaušanos apkārtējā zoba struktūrā.

CLEARFIL MAJESTY^TM ES FLOW priekšrocības

• Efektīva un ērta apstrāde – tūlītēja ievade, izmantojot šļirci, vienkārša un ērta pulēšana.
• Izturīgums – kompozītmateriāla lieces izturība ir 150 MPa, bet spiedes izturība ir 373 MPa.
• Plašs indikāciju diapazons – visas kavitāšu klases, cementēšana un labošana.
• Estētika – lieliska krāsu adaptācija, ko nodrošina gaismas difūzijas tehnoloģija.

KOMPOZĪTMATERIĀLS, KAS ZOBĀRSTIEM VIENMĒR JĀTUR PA ROKAI.

Plašāka informācija ir pieejama vietnē: kuraraynoritake.eu/lv/clearfil-majesty-es-flow
Kuraray Europe Benelux B.V., Nordics & Baltics l infobaltics@kuraray.com

Uzņēmums Kuraray Noritake Dental Inc. ir radies pēc uzņēmuma Kuraray Medical Inc. un Noritake Dental Supply Co. apvienošanās 2012. gada aprīlī. Šī uzņēmuma priekšrocības ir izcilas zināšanas par organisko un neorganisko ķīmiju, kas palīdzējušas izstrādāt arī citus augsta līmeņa zobārstniecības produktus – gan keramiskos, gan kompozītmateriālus un pat biomateriālus.

As a company, Kuraray Noritake Dental is committed not just to creating innovative products, but also to building upon our successes. A perfect example of this approach is CLEARFIL Universal Bond Quick, our newest universal dental bonding agent. A descendant of the original CLEARFIL BOND SYSTEM F and CLEARFIL SE BOND, this one-step adhesive eliminates the need for waiting, rubbing or applying additional layers. With the introduction of a flip-top cap, CLEARFIL Universal Bond Quick is now more compact and efficient than ever.

Easier than ever to use

Thanks to the new flip-top cap, the bottle can easily be opened, manipulated and closed with just one hand. In addition, its unique nozzle allows for controlled dispensing of the adhesive and ensures that there is minimal wastage. Together, these improvements are intended to enable ideal results for both the dentist and the patient.

Rapid bond technology

Though its container may be different, the patented monomer technology of Kuraray Noritake Dental still forms the backbone of this product. Other adhesives tend to rely on “slow monomers” with relatively slow dentinal penetration, but CLEARFIL Universal Bond Quick combines Kuraray’s famous MDP monomer—scientifically proven to deliver stronger and more stable bonds than other manufacturers’ MDP—with hydrophilic amide monomers. This allows it to penetrate the dentine faster and more efficiently and provide a stable, moisture-resistant sealing of the cavity.

Combine with PANAVIA SA Cement Universal and CLEARFIL DC CORE PLUS

This universal adhesive pairs excellently with CLEARFIL DC CORE PLUS, a dual-cure, radiopaque core build-up material, to deliver durable, long-lasting restorations that dentists can trust. Delivered in a convenient automix system, CLEARFIL DC CORE PLUS possesses excellent compressive and flexural strength, with a filler loading weight of 74wt%.

CLEARFIL Universal Bond Quick is also suited for use with PANAVIA SA Cement Universal, a resin cement that similarly utilises MDP monomer technology for durable bonding. PANAVIA SA Cement Universal possesses a stable three-year shelf life at room temperature, effectively eliminating the need for refrigeration, and its improved endo tip allows for greater precision and control over cement placement during post cementation.

By combining excellence in performance with simplicity in use, Kuraray Noritake Dental’s CLEARFIL Universal Bond Quick represents an evolution in dental bonding agents. 

As a dental technician with many years of experience, Björn Roland has always pursued one goal in his lab: restorations that seamlessly mimic natural dentition and possess reliable functionality. Here, he discusses how he integrates Kuraray Noritake Dental’s dental solutions into his daily workflow and shares some tips for creating aesthetically-pleasing dental restorations.

Could you speak a little bit about your dental journey and how you were first introduced to Kuraray Noritake Dental’s range of products?

ROLAND: Well, I was first introduced to these products when I was in Japan about 15 years ago. I was there to undertake a course at the Osaka Ceramic Training Center of Shigeo Kataoka, but I had the possibility during this time to visit courses conducted by Hitoshi Aoshima. Aoshima is the person primarily responsible for Noritake Porcelain and who had the idea for the colouring, and he was also responsible for the idea of internal staining. I also had the possibility to complete a course with Aoshima and visit his dental lab in Tokyo, which enabled me to begin working with Noritake porcelain when I arrived back in Germany.

You spoke at IDS 2019 about the evolution of the KATANA™ Zirconia range, starting with the 2013 introduction of KATANA™ Zirconia ML. When did you first start working with this product?

When Kuraray Noritake Dental was formed in 2012, I was lucky enough to be one the first dental technicians to experience the multilayered technology that forms the backbone of KATANA™ Zirconia, to test it out before it was released to the German market. Prior to this, there was only a monocoloured zirconia material available, which you could stain yourself by dipping it into a staining solution, but I was never a big fan of it. From the moment that Kuraray Noritake came up with its multilayered approach, I could see the potential of KATANA™ Zirconia -simply put, it was easy to use and had a nice and aesthetic colour shift when used for restorations.

As a dental technician, do you use KATANA™ Zirconia in your everyday workflow?

In our laboratory we only use KATANA™. Of course, not everything is made from the multilayered variety—we have primarily used the monocoloured KATANA™ HT for the framework in the past, though we do use the multilayered option for monolithic restorations and for certain frameworks.

Do you use KATANA™ Zirconia in combination with CERABIEN™ ZR porcelain?

Yes, always. For me, it is a perfect combination. Not only are they easy to use together, but they also combine to create aesthetic restorations with great, natural colour and a high level of flexural strength. In our laboratory, everyone uses CERABIEN™ ZR porcelain, from those who are just starting with ceramics through to the experienced and highly skilled dental technicians. Even technicians who have come from other dental laboratories and tried other porcelain materials have adapted very quickly to using it and seem to really like it. The chipping risk with CERABIEN™ ZR porcelain is very low, and we truly admire the brilliance of the colour.

Is CERABIEN™ ZR porcelain a material, in your opinion, that can benefit those with expert knowledge of porcelains?

Of course. For those who are experienced in dealing with ceramic materials and understand how they behave, they can absolutely achieve high-end results with CERABIEN™ ZR. It’s important to remember, though, that even dental technicians who aren’t so familiar with ceramic veneering are also getting good results out of it - it’s not too difficult to use and get good results.

Do you use any other Kuraray Noritake Dental products in your dental lab?

Apart from KATANA™ and CERABIEN™ ZR, one product that I personally like and use from Kuraray Noritake Dental is Meister Cones, which are these small paper cones that assist with the finishing and polishing of porcelain surfaces. I brought them back with me to Germany from Japan and find them to be very handy in the laboratory.