429 Too Many Requests

Virtual Kick-Off KATANA Zirconia Symposium

Lecture 1 of 3, Prof. Dr. Beuer
Watch how Prof. Dr. Beuer explains his experience with the new material. Two in one: Combining High Strength and High Translucent Zirconia.

Lecture 2 of 3, MDT Rondoni + MDT Rossi
Watch the recording of the KATANA Zirconia YML Online Symposium on July 3rd 2021, the second lecture plus hand-on which details the experience of MDT Rondoni and MDT Rossi with this new material.

Lecture 3 of 3 + Q&A, MDT Nondas Vlachopoulos
Mister Vlachopoulos deepdives in to a full procedure executed with the new material and demonstrates how liquid ceramics compliment the material establishing a very high-end aesthetic result.

Case by Dr. Shoji Kato of Takanawa Dental Office, Japan

1. After preparing the abutments

An anterior bridge made of crown and bridge resin has become dislodged. The abutments are vital teeth.

2. Prosthesis

A PFZ bridge with a frame fabricated using KATANA™ Zirconia HT12.

3. Application of Try-in Paste

Evaluate the shade of the cement before cementation.

4. Try-in

After checking the cement’s shade, rinse the prosthesis and tooth surface with water to remove Try-in Paste.

5. Pretreatment of the prosthesis (A)

Sandblast the prosthesis (at 0.3 to 0.4 MPa), clean with an ultrasonic cleaner for 2 minutes, then dry.

6. Pretreatment of the prosthesis (B)

Apply CLEARFIL™ CERAMIC PRIMER PLUS and blow dry with air.

7. Pretreatment of the abutments (C)

Apply Tooth Primer, allow it to react for 20 seconds, then blow dry with air.

8. Application of Paste

Use Universal.

9. Placement of the prosthesis

After placement, remove excess cement using a piece of gauze, a small brush, etc.

10. Light-curing

Light-cure the entire surface of the prosthesis, including the margins.

11. Final polymerization

Make sure the prosthesis is left in place, unmoved, for 3 minutes.

Article by Peter Schouten.

We've seen them all: composite fillings that function present clinically, but are too ‘visible’ to be called aesthetic. The much-used term 'white filling' is probably quite appropriate here. In comparison to the tooth structure, these restorations are too opaque, or sometimes too transparent.

How much better would it be if the composite helped to create a seamless transition between tooth structure and composite? The so-called 'blending'.

But what enables this 'blending’ of composite and tooth structure to occur? The secret lies in utilizing the right mix of different filler particles and resins which give CLEARFIL MAJESTY™ ES-2 its light-diffusing properties. By varying the proportion of light-diffusing particles and the amount of pigment, it's possible to create composites with differing light-scattering properties and opacities. The most opaque variants contain more light-diffusing particles and more pigment. The more translucent ones contain obviously less.

All CLEARFIL MAJESTY™ ES-2 variants have the same filler content. This is important, as it means that the mechanical properties of all the CLEARFIL MAJESTY™ ES-2 variants are the same. The more translucent variants contain more barium glass than the more opaque variants. A higher barium glass content can lead to a less workable composite. With CLEARFIL MAJESTY™ ES-2, this is not the case. Kuraray has mastered the silanization process to such an extent that all variants, whether translucent or opaque, have the same filler amount, without compromising on workability.

Light diffusion test

Light diffusion properties are easy to see if the thin composite slices are placed on a black and white paper background and then held a few millimeters above the paper. Composites with high diffusion properties make the black strip virtually invisible. They blend in more readily with their surroundings.

Since 2010, thanks to its increased translucency, KATANA™ HT has become paramount in fully meeting the ever more demanding aesthetics in restorations where a zirconia frame is used in combination with new generation ceramics CZR. Such ceramics feature an enhanced leucite balancing, which makes them stronger and more durable.

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Since 2013, ML-Multi Layer technology has made it possible to skip the infiltration phase through multi-layered dentine/enamel millable discs. Such Multi-layered discs allow CUT-BACK solutions that definitely improve the function-related result as the palatal part of the restoration can be manufactured by using KATANA™ ML Zirconia only. Thus, without limiting the aesthetic results (which are reached by enamel-ceramic LUSTER porcelain with “MICRO LAYERING technique”, the restoration benefits of the low abrasiveness of the functional-occlusal areas which is reached through simple and effective mechanical polishing without either surface staining or glasuring.

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New generation KATANA™ UTML and STML introduced in 2015 can be used for anterior restoration thanks to the cubic zirconia based products that have been made available to make it possible to conceive a bi-layer to mono-layer transition in most clinical situations.

Cubic zirconia features superior optical behavior. Although mechanically inferior in performance to conventional zirconia, KATANA™ UTML and STML are aging-resistant, while UTML offers the same translucency as lithium disilicate based solution.

“ZERO-CUTBACK technique” is one of the ideal techniques that can be achieved with cubic zirconia solution. They can perfectly replicate digital projects without any need for subsequent layering and can be easily painted and mechanically polished in the palatal area.

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Kuraray Noritake Dental has also developed CZR FC Paste Stain with a wide range of coloring pastes specially designed for full anatomical solution of multi-layered zirconia. Their effectiveness is proven to be enhanced when used with “ULTRA MICRO LAYERING technique” on thin glasure or thin transparent ceramic mass.

Another advantage with STML and UTML products is the lower thickness, respectful of the latest micro-invasive dentistry standards and current market requests.

Fig. 16.

Excellent flexural strengths higer than 550/750 MPa allow restoration to feature micro-invasive thicknesses from 0.4 mm on, p.e. on laminates. Unlike PFZ, zirconia lower thicknesses ensure better results.

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Above all, new generation zirconia makes the digital work-flow more efficient and performing, from the intra-oral impression to the final product which can be manufactured “model-free”.

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Thus a new procedure standard is introduced, where simplified adhesive cementation through composite cements opens the the way to zirconia-based adhesive restoration techniques. Regarding adhesion, unlike glass-ceramic, zirconia is not etchable, yet it can be fixed through phosphate monomer MDP, i.e. Panavia™ V5

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Dentist:

DANIELE RONDONI, MDT

• Graduating in 1979, Daniele Rondoni opened a laboratory in 1982, which is also the home of the AAT Community College he founded.
• Teacher and counsellor for the “Italian School for Dental Technicians”at the University of Chieti, University of Sienna and University of Rome Tor Vergata.
• EAED and IAED Active Member and a SICED Associate and O.L.
• International Instructor for Kuraray Noritake Dental products.
• Author of “Tecnica della Multistratificazione in ceramica” (Ceramic Multilayering Technique) and a lab manual about the use of composite materials, introducing his own method – the “Inverted Hardness Layering System”.

Case by Dr. Salvatore Scolavino

After decades of developing and improving the matrix chemistry and filler technology contained in resinbased composites, the products available for direct restorative procedures finally seemed technically mature. What remained challenging, however, was the management of the extremely wide range of tooth shades and opacities available for each product: The dentin, body and enamel masses had to be selected and combined in the right way to obtain a perfect colour match and optical integration with the surrounding tooth structure. The difficulties associated with shade selection and calibration of layer thicknesses (particularly the top enamel layer) required to obtain the desired optical (desaturation) effects have now also finally been overcome.

The reason is that further improvements of the composites’ optical properties, mainly achieved through a careful selection and combination of fillers, have enabled the production of materials with optimized light diffusion properties. These properties enable the restorations to blend in smoothly with the adjacent tooth structure, thus paving the way for a single-shade concept (SSC). This concept involves the use of a single mass of composite to restore the function and aesthetics compromised by the loss of dental structure.

This translates into a significant saving of chair time and a high predictability of aesthetic outcome. A composite material supporting a single-shade technique needs to have medium opacity and a technology ensuring that the incoming light is absorbed, reflected and scattered in the right way to merge effortlessly with the surrounding natural dentition and create a biomimetic effect. The following clinical case reveals how the Light Diffusion Technology used in the CLEARFIL MAJESTY™ ES-2 Universal composite system (Kuraray Noritake Dental Inc.) leads to a highly predictable aesthetic integration obtained using the SSC.

Case description

The 30-year-old female patient presented for a check-up, during which it appeared that her composite restorations in the second quadrant (the maxillary left first and second molar) needed to be replaced due to marginal leakage (Fig. 1). Once the rubber dam was in place (Fig. 2), the existing composite restorations were removed using a round multi-blade bur, which allowing for a selective removal of composite and carious tissue. The extension of the cavity was performed with a truncated cone diamond bur (fine). Once the cavity preparation was completed (Fig. 3), the enamel and dentin surfaces were cleaned by sandblasting with aluminium oxide (50 μm). Selective etching of the enamel was performed with K-ETCHANT Syringe (Kuraray Noritake Dental; Fig. 4), followed by thorough rinsing and drying of the tooth (Fig. 5). For the adhesive procedure with CLEARFIL™ SE BOND 2 (Kuraray Noritake Dental), the primer was applied first (Fig. 6), rubbed into the tooth surface for 40 seconds and air-dried. The bond was subsequently applied in the same manner (Fig. 7). After several seconds of air flowing to create homogeneous surface the adhesive was light-cured for 40 seconds (Fig. 8). As the last phase of the adhesive procedure, a 1-mm-thick layer of flowable composite (CLEARFIL MAJESTY™ ES-Flow Super Low A3, Kuraray Noritake Dental) was applied to cover the adhesive on the dentin (Figs. 9 and 10).

Fig. 1. Pre-operative clinical image.

Fig. 2. Isolation with rubber dam.

Fig. 3. First and second molar after cavity preparation.

Fig. 4. Selective etching of the enamel.

Fig. 5. Cavities ready for the adhesive procedure.

Fig. 6. Application of the tooth primer.

Fig. 7. Glossy appearance of the cavities after application of the bond.

Fig. 8. Light-curing of the adhesive layer.

Fig. 9. Application of flowable composite.

Fig. 10. Cusp-by-cusp modelling of the universal composite.

In the modelling phase, the posterior shade U of the composite CLEARFIL MAJESTY™ ES-2 Universal was placed using the cusp-by-cusp technique (Figs. 11 and 12). In order to improve the optical integration of the restorations, some brown stain (CHROMA ZONE™ COLOR STAIN Dark Brown, Kuraray Noritake Dental) was added to the fissures (Fig. 13). For finishing, we used a multi-blade ball-shaped bur and an Arkansas Flame abrasive stone (Fig. 14). Polishing of the restorations was accomplished with the TWIST™ DIA system (EVE; Fig. 15). After rubber dam removal, the occlusal check was performed with articulating paper (Fig. 16), minimal adjustments were made and the surfaces repolished. The integration of the restorations after 30 days fully meets the clinical expectations (Figs. 17 to 20).

Fig. 11. Glossy appearance of the cavities after application of the bond.

Fig. 12. Completed occlusal anatomy.

Fig. 13. Stained fissures.

Fig. 14. Matte surfaces after finishing.

Fig. 15. High-gloss surfaces after polishing.

FINAL SITUATION

Fig. 16. Whole quadrant after rubber dam removal and the occlusal check.

Fig. 17. Whole quadrant at the 1-month-recall.

Fig. 18. Occlusal view of the restorations …

Fig. 19. … after one month.

Conclusion

The innovative composite system CLEARFIL MAJESTY™ ES-2 Universal, which consists of two shades for the anterior and a single shade option for the posterior region, offers the properties needed for a successful implementation of the single shade technique. Used in the posterior region, the material is sufficiently opaque to mask optical irregularities of the underlying tooth structure, while it is translucent enough to provide for an imperceptible optical transition from the tooth structure to the restoration. Irrespective of the tooth shade, the restoration merges smoothly with the surrounding natural dentition, creating a harmonic overall picture.

Dentist:

DR. SALVATORE SCOLAVINO

Dr. Salvatore Scolavino, graduated with honors in Dentistry and Dental Prosthesis from the University of Naples. Dr. Salvatore is a specialist in aesthetics and direct and indirect anterior and posterior adhesive restorations. His focus lies with Conservation, Endodontics and Prosthetics in particular. He is an active member of prestigious academies and scientific societies: AIC -Italian Academy of Conservation, IAED -Italian Academy of Esthetic Dentistry and SIDOC (Italian Society of Conservative Dentistry. Since 2004, he has private practice Nola, Italy.

Dr. Scolavino is a founder of werestoreit.it, an inspiring site that offers abundance and variety of aesthetic clinical cases. Author of the book published by Quintessence Publishing „Direct Restorations in the posterior regions“, author of scientific publications in national and international journals, he is speaker at courses and conferences in Italy and abroad.

By Univ.-Prof. Dr. Florian Beuer MME

There is still some confusion among dental practitioners about how to cement zirconia restorations. In general, all types of cements – adhesive or self-adhesive resin cements and conventional cements – are compatible with all types of zirconia. The actual choice should be based on the restoration design (retentive or non-retentive), the translucency of the zirconia and the clinical situation (feasibility of working field isolation).

When to use which type of cement

The use of adhesive resin cements is mandatory whenever the highest possible bond strength is required. This is the case with one-wing Maryland bridges and other types of restorations lacking micromechanical retention, and with two-piece implant abutments.

In some other situations where retention is not an issue, adhesive or self-adhesive resin cements may have a beneficial effect. The major reason is their more esthetic appearance compared to conventional cements, which offers advantages whenever a highly translucent restorative material is used (e.g. KATANA Zirconia UTML). An important precondition for adhesive luting, however, is a dry working field. Consequently, conventional cements are preferable in the context of placing crowns, bridges and other types of restorations with retentive designs whenever opaque zirconia framework materials are used and / or it is difficult to ensure a dry working field.

How to pre-treat the tooth and the restoration

The highest bond strength of adhesive resin cements to zirconia is obtained after sandblasting with alumina (particle size max. 50 µm, pressure approx. 1 bar). Hence, this procedure is highly recommended. Subsequent steps may be different depending on the cement system employed and should be carried out according to the manufacturer’s instructions for use. On the side of the tooth, enamel etching is important independent of the products used.

Which products to use

In each of the cement classes, there are many different products to choose from. My recommendation is to select a proven and easy-to-use luting material. Among those products achieving the same high bond strength, the solution requiring the fewest application steps seems preferable as it reduces the risk of application errors. At Charité – University Medicine Berlin, we count on PANAVIA cements, which are based on many years of expertise in developing products for adhesive luting of zirconia.

Dentist:

PROF. DR. FLORIAN BEUER

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

Case by Daniele Rondoni, MDT

Evolution in the field of aesthetic dentistry never stops: KATANA™ Zirconia proves its aesthetic potential while also being great function-wise. The full zirconia palatal area is combined with an aesthetic buccal part where CZR Luster mass is only used.

Fig. 1. KATANA™ Zirconia HTML with vestibular cut-back opalescence bio-design.

Fig. 2. Palatal ”zirconia-free“ solution.

Fig. 3. Aesthetic vestibular layering with Luster porcelain.

Fig. 4. Manually polished palatal surface with Pearl Surface Z diamond paste.

Fig. 5. Self glazing in furnace for vestibular porcelain.

Fig. 6. Initial case.

Fig. 7. Hybrid solution.

Fig. 8. Palatal Zirconia free.

FINAL SITUATION

Fig. 9. 4 Years follow-up.

Dentist:

DANIELE RONDONI, MDT

Born in Savona in 1961 where he lives and has worked in his own laboratory since 1982 with his collaborators. Graduated from the dental technician school IPSIA “P. Gaslini” in Genoa in 1979. He continued his education by attending relevant workshops for the “Italian dental school“ and broadened his professional experience in Switzerland, Germany and Japan. Since 2011 Kuraray Noritake Dental International Instructor.

With CLEARFIL MAJESTY™ ES-2, the shade transition from composite to tooth is virtually invisible. The secret to this lies in light diffusion technology. How does this work?

Before we discuss the technology in detail, here are some more information about our CLEARFIL MAJESTY™ ES-2 composites. All CLEARFIL MAJESTY™ ES-2 composites are suitable for both anterior and posterior applications. The different variants within the ES-2 family are characterized by supreme handling and a long working time, and the fact that they do not slump during modeling. A key feature of these composites is the ease with which restorations blend into their surroundings. This results in durable and aesthetic restorations.

In CLEARFIL MAJESTY™ ES-2 composites, two types of fillers are used. Barium glass particles form the basis of the filler. Alongside this, advanced prepolymerized filler particles are added. The latter type is called light diffusion filler, since it is primarily these filler particles that achieve a light-scattering effect within the composite.

The way in which a restoration 'adjusts itself', to the shade of the tooth to be restored, is not the same for all composites. Most composite manufacturers make use of the so-called 'chameleon effect'. A composite that is sufficiently translucent allows light to pass through. Light is reflected off the walls of the cavity, whereby the composite restoration assumes the shade of the adjacent tooth structure.

In cavities that aren't too large with a sufficient amount of surrounding tooth structure, this chameleon effect works well enough. However, with larger cavities or in the absence of underlying tooth structure, as is often the case with anterior restorations, the aesthetic blending effect is limited. The brightness is far from satisfactory, and the restoration looks gray.

At Kuraray Noritake Dental Inc., we do things differently.

Besides the optimized translucency in CLEARFIL MAJESTY™ ES-2 composites, it's the light diffusion technology that makes the restoration blend seamlessly with the adjacent tooth structure. Thanks to the combination of these two parameters — translucency and light diffusion — the capabilities are far more extensive than with just translucency.

The different dental tissues have different opacities. Enamel is more translucent than dentin. However, the degree of translucency/opacity of both tissues is not always the same. Age, thickness of the structure and various intrinsic and extrinsic factors all play a role.

Depending on the desired end result, the most appropriate member(s) of the CLEARFIL MAJESTY™ ES-2 family is/are selected for the restoration.

In aesthetic restorations in which opacity differences need to be considered, a layering system is necessary. More uniform restorations are easily constructed with a composite that has broad shade and opacity coverage.

CLEARFIL MAJESTY™ ES-2 Premium for highly esthetic restorations.

CLEARFIL MAJESTY™ ES-2 Universal for routine aesthetic restorations involving few or no opacity differences.

By Kazunobu Yamada, RDT

With the new KATANA™ Zirconia YML it is extraordinarily easy to produce beautiful restorations. Brilliance and vitality may be added simply by applying CERABIEN™ ZR FC Paste Stain to the monolithic restoration after surface preparation.

A possible technique is demonstrated by Kazunobu Yamada, RDT, in this video.

What if Kuraray Noritake Dental had not developed the MDP monomer?

What would the quality of adhesive dentistry be if Kuraray Noritake had not developed the MDP monomer? MDP has proved to be a very effective functional monomer for creating durable bonding to enamel, dentine and metals. The best-known products containing MDP are CLEARFIL™ SE BOND and PANAVIA™.

Structure of Adhesive monomer MDP

Adhesion to various substrates is possible Thanks to MDP (methacryloyloxydecyl dihydrogen phosphate), which has been shown to create a long term, durable and stable bond to both dental tissue and metal oxides. Research conducted over the past few decades has demonstrated the effectiveness of MDP. The first Kuraray Noritake Dental product to contain MDP was PANAVIA EX. Various other adhesive and cementation systems followed. Our latest products, PANAVIA™ V5 and CLEARFIL™ Universal Bond, also rely to a large extent on the performance of the original MDP monomer. MDP has the following structure:

1. terminal double bond group for polymerisation
2. hydrophobic alkylene group to maintain a delicate balance between hydrophobic and hydrophilic properties and
3. hydrophilic phosphate group for performance of the acid demineralisation and chemical bonding to tooth structure.

Fig. 1. The chemical structure of adhesive monomer (MDP).

History

In the years between 1978 and the late 1990s, it became possible to increase the bond strength to dentine to more than the intrinsic strength of the dentine itself. MDP played a major role in these developments. The solid ionic bond with calcium from the HAp in dental tissue means that such failures as occur are cohesive in the dentine rather than being failures of the adhesive. Apart from in vitro studies confirming this bond strength, the long term clinical durability recorded over 13 years is also impressive.

Research

Research from Yaun et al., 2007, shows that defects along the interface are largely responsible for degradation of the hybrid layer. CLEARFIL™ SE BOND exhibited no such defects. So it was expected that SE BOND would also prove to have a stable connection to dental tissue. Recently, Peumans et al. From Leuven University, Belgium found CLEARFIL™ SE BOND to still have excellent clinical effectiveness after 13 years.

In their publication in the Journal of Dental Research 83, 2004, Yoshida et al. concluded that the choice of the adhesive monomer played a significant role in the effectiveness of the adhesive. They found MDP to be the best and fastest in tests for chemical adhesion (ionic bonding) and stability in a moist environment (insoluble) – better and more stable than 4-MET and Phenyl-P, in that order.

After 35 years, MDP is still in a class of its own. To date, no manufacturer has been able to develop an adhesive monomer with better adhesion properties combined with durable bond strength. Many attempts have been made, but none have succeeded. In the meantime, Kuraray’s patent on MDP has expired. This has opened up the market for other manufacturers to synthesise their own MDP. Only a few non-dental chemical companies are supplying MDP to other manufacturers of adhesive systems, and the synthesis of high-purity MDP remains extremely difficult.

More recently, Kumiko Yoshihara et al. published ‘Functional monomer impurity affects adhesive performance’, in Dental Materials 31 (2015) 1493-1501. They concluded that the three MDP’s they studied exhibited different levels of purity. Differences in the resultant hybrid layers were observed in all three MDP versions: both impurities and the presence of dimers had an effect on the etching efficacy of the HAp, and also on the intensity of nano-layer presence and the immediate bond strength.

μTBS of MDP’s from different origin

Yoshihara Ket al. Functional monomer impurity affects adhesive performance Dent Mater 31, 1493-1501, 2015.

Fig. 2.

Explanation

The three 10-MDP’s studied in this study clearly revealed a different purity. Differences in the ultrastructure of the resultant hybrid layers were observed for the three 10-MDP versions. Both the impurities and the presence of dimers affected the etching efficacy of HAp, the intensity of nano layering and the ïmmediate’ bond strength.

“The purity of 10-MDP present in commercial dental primers, adhesives and cements can be expected to influence bonding performance.”