Satoshi Yamaguchi, President, Kuraray Noritake Dental Inc.

KURARAY NORITAKE DENTAL INC. EXCELS IN DENTAL TECHNOLOGY, FOCUSING ON STRENGTH, AESTHETICS AND GLOBAL ADAPTABILITY

Kuraray Noritake Dental Inc., a leader in dental materials and technology, blends innovation with a deep commitment to oral health. Established from the merger of Kuraray Medical Inc. and Noritake Dental Supply Co., Limited, the company excels in providing dental bonding agents, fillings, cements, porcelains, zirconia and CAD/CAM blocks. This synergy has allowed the company to push the boundaries of dental science.

“We aim to enhance global oral health and wellness.”

President Satoshi Yamaguchi highlights the company's approach: "We focus on strength, aesthetics and speed in our products. By developing our own zirconia powder and partnering with CAD/CAM system manufacturers, we achieve high-quality, durable and efficient dental solutions." This commitment is evident in the firm's flagship product, KATANA™ Zirconia Block, renowned for its durability and aesthetic appeal.

Kuraray Noritake Dental is also striving to develop new products for more longterm predictable dental treatment with bioactive properties. The company is not just focused on developed markets like the U.S. and Europe. Mr. Yamaguchi explains: "Understanding local treatment situations is key. In addition to the U.S. and Europe, having sales offices in places like Brazil and China helps us tailor our products to regional demands." This global presence ensures the company remains at the forefront of dental technology, adapting to diverse market needs.

Tooth crown made from KATANA™ Zirconia

Looking ahead, Mr. Yamaguchi envisions Kuraray Noritake Dental as more than just a technological innovator. "In five years, I hope we are seen not only as a tech company but as a holistic provider of oral care solutions," he says. With a commitment to reducing "invisible stress" for dental professionals and patients, the company aims to enhance global oral health and wellness.Original article published in Newsweek Magazine on September 20th, 2024 Written by The Worldfolio

Article by Dr. Florian Zwiener

Modern multi-layered zirconia such as KATANA™ Zirconia STML (Kuraray Noritake Dental Inc.) already meets high aesthetic demands due to its natural colour gradient and high translucency. To achieve further characterisation and optical adjustment to the adjacent teeth, there are essentially two options: veneering with feldspathic ceramic or glazing and individualisation with ceramic stains.

While there are still many indications for veneering, especially in the anterior area, more and more cases can now be solved with monolithic restorations. This allows for a time-efficient chairside workflow with same-day treatment, eliminating the need for temporary restorations. Additionally, the absence of a porcelain layer reduces the wall thickness of the restoration and thus the space required, allowing for less invasive preparation. This also reduces the risk of endodontic complications induced by tooth preparation (grinding trauma). Another advantage is a significant reduction in the chipping risk.

Below are the essential steps for individualisation using ceramic stains, demonstrated through the example of a molar crown.

PREPARATION

The restoration is designed in full contour as usual, ideally dry-milled, and then sintered. After sintering, the restoration is first sandblasted (aluminium oxide 50 μm, 1 to 1.5 bar pressure). This microscopic roughening of the ceramic surface enables an optimal bond with the glaze. Subsequently, the restoration should be cleaned using a steam cleaner or an ultrasonic cleaner to remove all blasting residue.

The functional restoration surfaces must then be polished to avoid the risk of excessive abrasion on the enamel of the opposing dentition, as zirconia is harder than enamel. Following this, optional glazing and characterization with ceramic stains can be performed. However, for areas not in the aesthetic zone, such as the palatal surfaces of maxillary anterior teeth, this is not necessarily required.

PREPARATION: STEPS AT A GLANCE

1. Sandblasting of the sintered restoration (Al2O3 50 μm, 1-1.5 bar)
2. Cleaning (steam cleaner or ultrasonic cleaner)
3. Polishing the occlusal/palatal contact areas

Fig. 1. Sintered and sandblasted zirconia crown.

Fig. 2. Occlusal high-gloss polish.

Fig. 3. TWIST™ DIA for Zirconia (Kuraray Noritake Dental Inc.) enables efficient polishing of zirconia in three steps.

STAINING AND GLAZING

The shades A+, B+, C+, and D+ of the paste-like ceramic stain CERABIEN™ ZR FC Paste Stain (Kuraray Noritake Dental Inc.) enhance the chroma in the cervical area when applied in the respective tooth shade. They are used to strengthen the multicolour effect of the zirconia or to darken the restoration overall. By mixing the stains with glaze or clear glaze in different ratios, the intensity can be adjusted.

Cervical 1 and 2 are suitable for replicating exposed cervical areas or discolouration. Cervical 1 is also useful for marking fissures, as it gives the crown depth and structure without appearing overly dark. Patients typically reject excessively pronounced fissure effects. Since fissure areas in multi-layered materials generally lie in the lightest part of the block (in the enamel layer), it may make sense to darken them slightly with A+, while white hypermineralisations can be replicated on the cusp tips. A narrow band of Grayish Blue below the cusp tips creates an optical translucency effect. In cases where this translucency appears too dark blue or greyish, mixing Grayish Blue with Dark Grey can modify the appearance.

By mixing various colours, numerous different tones can be created. For instance, by adding Yellow to A+, its slightly brownish colour can be adjusted to a warmer, more yellowish tooth shade. It is generally advisable to capture the patient‘s tooth shade with a photo and a custom-made colour ring of the corresponding material before preparation. This can serve as a reference during production, especially in the laboratory, where lighting conditions may differ.

For pronounced characterisations or fine details, it may be necessary to carry out multiple firings to avoid unwanted running effects between the colours and the glaze. This is particularly recommended when replicating anatomical details with high sharpness, such as enamel cracks or local discolourations. For this, a glaze and base shade are first applied and fired, and finer structures are added in a second firing. Alternatively, a fixative firing of the stains without glaze can be performed first, with only a glaze layer fired in the second step. A benefit of CERABIEN™ ZR FC Paste Stain is that its appearance during application closely matches the final firing result. In thick consistency, glaze can also be used to easily rebuild missing proximal contacts.

STAINING AND GLAZING: STEPS AT A GLANCE

1. Glaze with Glaze/Clear Glaze
2. Increase chroma (in the cervical area or over large areas) with A+, B+, C+, or D+
   - Adjust intensity by mixing with Glaze/Clear Glaze
   - Create a warmer tone by mixing with Yellow
3. Replicate discolouration/exposed cervical areas: Cervical 1 and 2
4. Customise fissure areas
   - Darken with A+, B+, C+, or D+
   - Accentuate fissures with Cervical 1
5. Customise cusp tips
   - Replicate hypermineralisations with White
   - Create a band below with Grayish Blue (translucency effect)
   - Adjust translucency effect below cusp tips by mixing with Dark Grey
6. Firing

Alternatives:

1. First firing: Glaze plus base shade, second firing: Finer structures
2. First firing: Fixative stain firing without glaze, second firing: Glaze firing

Fig. 4. CERABIEN™ ZR FC Paste Stain assortment for the practice laboratory.

Fig. 5. Discoloured fissures can be accurately replicated with an ISO10 endodontic file.

Fig. 6 and 7. Glazing and staining in one firing.

Fig. 8. Shade determination using a custom-made KATANA™ Zirconia STML colour ring (A3.5).

Fig. 9. Bridge made from KATANA™ Zirconia STML, sandblasted and occlusally polished.

Fig. 10. Finished glazed and characterised restoration.

Fig. 11. Bridge 14-16 in place.

FINAL SITUATION

Fig. 11. Bridge 14-16 in place.

Dentist:

FLORIAN ZWIENER

Case by MDT Daniele Rondoni and Dr. Enzo Attanasio.

Veneers made of zirconia? In some cases, like the one presented below, monolithic zirconia veneers may be an option. Reasons for selecting a latest-generation zirconia such as “KATANA™ Zirconia” YML include its very high translucency and a wall thickness of only 0.3 to 0.4 mm supporting minimally invasive tooth preparation. Due to a highly automated production procedure, the manual effort involved may be reduced, while highly aesthetic outcomes are possible.

Fig. 1. Initial situation: Young female patient with misshaped and misaligned maxillary incisors. Digital smile design is used to reveal the ideal proportions and positions of the anterior teeth.

Fig. 2. Ideal tooth proportions and positions displayed over a picture of the teeth after orthodontic treatment and the creation of a mock-up. The positions are ideal and the tooth shapes obtained with the mock-up only need some minor adjustments.

Fig. 3. Facial view of the patient with the planned veneers blended in.

Fig. 4. Guided tooth structure removal with the aid of a silicone index. The minimum wall thickness of the selected material – “KATANA™ Zirconia” YML – is 0.4 mm.

Fig. 5. Matched digital impressions of the maxilla and mandible taken after tooth preparation.

Fig. 6. Monolithic restoration made of “KATANA™ Zirconia” YML placed on the resin model after the 7-hour final sintering.

Fig. 7. Lateral view of the master cast with the six veneers individualized with the liquid ceramic system CERABIEN™ FC Paste Stain.

Fig. 8. Tooth-like translucency of the veneers on the model.

Fig. 9. Intra-oral try-in with two different shades of the PANAVIA™ V5 Try-in Paste: A2 is used in the right and Clear in the left quadrant. It was decided by the dentist to use A2 shade.

Fig. 10. Lateral view of the cemented veneers. The result is a natural surface texture, which contributes to a natural appearance of the restorations.

Fig. 11. Frontal view of the veneers in place.

Fig. 12. Treatment outcome immediately after rubber dam removal.

FINAL SITUATION

Fig. 13. Treatment outcome with healthy soft tissues two weeks after treatment.

Fig. 14. Gums are healthy and the restorations show a great optical integration with the adjacent posterior teeth.

Dentists:

CLEARFIL MAJESTY™ ES FLOW RECEIVES “NIOM TESTED” QUALITY SEAL

Before being allowed to market a dental composite filling material, it must, among other things, meet the set standards within ISO 4049:2019 Dentistry - Polymer-based restorative materials. Prompted by the tremendous positive response Kuraray Noritake Dental Inc. received from users of the CLEARFIL MAJESTY™ ES Flow series, we asked the Nordic Institute of Dental Materials (NIOM), an independent research institute, to test this product line on key aspects within the said ISO standard.

While it was not mandatory for us to have the CLEARFIL MAJESTY™ ES Flow series tested, our confidence in the quality of our product prompted us to do so. NIOM thoroughly evaluated CLEARFIL MAJESTY™ ES Flow in all three different levels of flowability: High, Low, and Super Low (Fig. 1). Among the properties assessed were depth of cure, flexural strength, water sorption and solubility, and colour stability after irradiation and water sorption. NIOM found that regarding all properties, the three flowabilities and different shades proved to comply with the requirements.

We are pleased to have gone the extra mile and proud that an independent party verified that our product meets the stringent ISO standards.

Fig. 1. CLEARFIL MAJESTY™ ES Flow in its three different levels of flowability.

IMPLICATIONS FOR CLINICAL USE

These test results are an external proof for users of the popular flowable composite series that they safely can be used as specified by Kuraray Noritake Dental Inc. in the product’s instructions for use. The NIOM test results obtained regarding the depth of cure imply that, when applied to the recommended layer thickness, the composite will polymerise adequately – which is essential for a great long-term performance. In addition, all three flowabilities offer sufficient strength and water sorption/solubility behaviour even to be suitable for restorations, including the occlusal surface of molars and pre-molars. This means that the materials are very well suited for a wide range of indications, including restoring all cavity classes and repairing existing restorations and cementing (Fig. 2).


Fig. 2. Three variants of CLEARFIL MAJESTY™ ES Flow and the suggested use areas.

GREAT AESTHETICS AND HANDLING

On top of these well-balanced mechanical properties, CLEARFIL MAJESTY™ ES Flow in its innovative syringe handles well due to an easy dispensing, bubble-free application, easy sculpting facilitated by its non-sticky formulation, and easy polishing behaviour. Coming in a variety of shades (Fig. 3) and equipped with proprietary Light Diffusion Technology, the material in its three different levels of flowability blends nicely and effortlessly with the surrounding tooth structure, creating a natural overall look. Both handling and aesthetics have been rated very good to excellent by dental advisor consultants in the context of a clinical evaluation.

Fig. 3. Overview of shades available per flowability.

NIOM also provides proof of the positive aesthetic properties: the institute's tests to evaluate colour stability after irradiation and water sorption reveal that CLEARFIL MAJESTY™ ES Flow is expected to remain stable over time. This feature is important for the long-term aesthetics of the restorations created with the materials.

Choose a reliable, high-quality, flowable, direct restorative material that withstands rigorous testing.

Case by Dr. Enzo Attanasio

The selection of the restorative material is a crucial step in prosthodontics. Hybrid ceramics offer a range of properties well-suited for various therapeutic situations, both in the presence of vital teeth and of endodontically treated teeth. Using the example of a clinical case, this article will explore the advantages associated with the use of hybrid ceramics in a cracked tooth syndrome scenario.

INITIAL SITUATION

The affected tooth in this case was a mandibular right second premolar (45 according to the FDI notation) with an old amalgam restoration (Figs. 1 and 2). The patient experienced pain upon chewing (specifically upon release). Clinically, there were visible horizontal and vertical crack lines. The tooth was vital and showed no signs of pulpal pathology. It was decided to replace the amalgam restoration and restore the tooth with an overlay made of the hybrid ceramic KATANA™ AVENCIA™ Block. There were two main reasons for this decision. First, whenever root canal treatment would be necessary in the future, the hybrid ceramic material would facilitate endodontic access cavity preparation (compared to any other ceramic material) and subsequent restoration with composite filling material. Second, hybrid ceramics offer greater resistance and improved mechanical properties compared to composite filling materials applied in an incremental layering technique.

Fig. 1. Initial situation: Occlusal view.

Fig. 2. Initial situation: Buccal view.

PREPARATION AND IMMEDIATE DENTIN SEALING

To remove the amalgam restoration and weakened surrounding tooth structure, the occlusal surface of the tooth was reduced by approximately 2 mm. For a smooth colour transition between the tooth and the restoration, the preparation outline was created at the level of interproximal boxes with a vestibular inclined plane (Fig. 3). Subsequently, Immediate Dentinal Sealing (IDS) was carried out (Figs. 4 to 10). This technique involves the use of a universal adhesive like CLEARFIL™ Universal Bond Quick, which is applied to the preparation without prior etching of the peripheral enamel. In the second step, a highly filled flowable composite is applied. In the present case, the material of choice was CLEARFIL MAJESTY™ ES Flow Super Low, applied in a thickness of just 0.5 mm. The preparation was refined using ultrasonic instrumentation: Sonic tips SFM7 and SFD7 (Komet Dental) for refining the boxes; SFD1F and SFM1F (Komet Dental) for margins and steps. Sharp edges were rounded with abrasive discs and then polished with fine polishers. It is crucial that the residual occlusal thickness (prosthetic space) is 1.5 mm, as required by the selected material.

Fig. 3. Prepared tooth structure prior to immediate dentin sealing.

Fig. 4. IDS: Application of the universal adhesive.

Fig. 5. IDS: Light curing of the adhesive layer.

Fig. 6. Thin layer of flowable composite applied to the preparation.

Fig. 7. Contouring, …

Fig. 8. … rounding off sharp edges …

Fig. 9. … and polishing of the sealed surface with dedicated instruments.

Fig. 10. Sealed tooth preparation ready for impression taking.

FROM SCANNING TO TRY-IN

Following digital scanning with the intraoral scanner Primescan™ (Dentsply Sirona), MDT Daniele Rondoni produced the restoration (Figs. 11 and 12). The cementation process involves an initial try in phase to assess the marginal fit of the overlay and the contact areas. Testing occlusion at this stage could be risky as it may lead to fracture of the restoration in case of excessive premature contacts. After try-in (when carried out without rubber dam), the restoration may be contaminated by blood, saliva, or glycerin gel used for the evaluation of fit and aesthetics. Therefore, it is necessary to clean the restoration before proceeding with adhesive phases. The use of a cotton pellet soaked in alcohol is an option, a cleaning agent like KATANA™ Cleaner may be even better as it chemically cleans the restoration and eliminates the contaminants.

Fig. 11. Hybrid ceramic overlay on the printed model.

Fig. 12. Separate overlay.

CONDITIONING OF THE TOOTH AND THE RESTORATION

Afterwards, the restoration was sandblasted (as recommended for most hybrid ceramics) with 50 μm aluminum oxide using AquaCare (Akura Medical) (Fig. 13), and then immersed in distilled water in an ultrasonic bath for 5 minutes. Meanwhile, rubber dam was placed over the entire sextant, the build-up was sandblasted like the intaglio of the overlay and a phosphoric acid etchant (Ultra Etch, Ultradent) was applied to the enamel, rinsed off and the area dried (Figs. 14 to 17). The clean restoration was subsequently conditioned with a silane containing 10-MDP (CLEARFIL™ Ceramic Primer Plus, Kuraray Noritake Dental Inc.) according to the manufacturer’s instructions (Fig. 18). What followed was the application of the universal adhesive (CLEARFIL™ Universal Bond Quick) to the intaglio of the overlay and to the preparation and light curing on both sites (Figs. 19 and 20). One of the advantages of universal adhesives compared to three-step adhesive systems is their minimal film thickness, which does not compromise the fit of the restoration.

It is important to protect adjacent teeth with metal matrix strips during adhesive phases to provide for proper fitting. These elements do not create operational difficulties, but serve their purpose: After restoration placement, the composite or cement used for placement will be easily removable from the mesial and distal surfaces of the adjacent teeth, as they are free of adhesive.

Fig. 13. Sandblasting of the overlay …

Fig. 14. … and the tooth structure.

Fig. 15. Selective etching of the enamel, …

Fig. 16. … followed by thorough rinsing. Adjacent teeth are protected by a metal matrix strip.

Fig. 17. Tooth structure after selective etching, rinsing and drying.

Fig. 18. Silane application.

Fig. 19. Application of the universal adhesive into the overlay.

Fig. 20. Treatment of the tooth structure with the universal adhesive.

DEFINITIVE PLACEMENT

In the present case, a heated composite paste (heated to a temperature of 55 °C) was extruded into the restoration, which was then placed by applying slow, gradual, and strong pressure (Figs. 21 and 22). Excess composite was removed with a scaler in the buccal and lingual areas and floss (e.g. SuperFloss®, Oral-B) in the interproximal areas. Several pressurization phases were performed until no more composite was observed at the tooth-restoration interface.

Fig. 21. Heated composite paste used for definitive placement.

Fig. 22. Restoration placed under rubber dam isolation.

Then, the composite was polymerized for 30 seconds from the buccal and lingual sides with two curing lights, before applying glycerin gel to the margins and polymerizing from occlusal for another minute (Fig. 23). If thorough attention is given to removing excess composite during placement phases, subsequent finishing steps will be quick and easy (Figs. 24 to 27). Finishing and polishing of the interproximal areas was accomplished with an EVA handpiece and 3M™ Sof-Lex™ Finishing Strips (3M). For finishing of the buccal and lingual areas, a medium-grit, flame-shaped diamond bur (diameter 14/16) was used. Finally, the margins should be polished using composite polishers like TWIST™ DIA for Composite (Kuraray Noritake Dental Inc.). After the local anesthesia wears off, one should observe the cessation of pain symptoms, as seen in the present case. The treatment outcome is displayed in Figures 28 and 29.

Fig. 23. Light curing through a layer of glycerin gel blocking the oxygen.

Fig. 24. Finishing of the buccal and lingual margin with a medium-grid, flame-shaped diamond bur.

Fig. 25. Finishing of the interproximal areas with EVA handpiece (fine grain).

Fig. 26. Checking the occlusal contacts.

Fig. 27. Occlusal polishing.

FINAL SITUATION

Fig. 28. Treatment outcome – buccal view.

Fig. 29. Treatment outcome – occlusal view.

CONCLUSION

For posterior teeth restored with amalgam and a significant level of destruction, restoration replacement with hybrid ceramic overlays can be a great option. Mechanical material properties are usually superior to those of layered composites, processing is possible chairside or labside and comparatively quick (no firing required), while the clinical placement procedure is similar to that involved in placing glass ceramics – with the major difference of sandblasting instead of etching the intaglio of the restoration. One of the most important benefits of hybrid ceramics over glass ceramics, however, is the ability to modify the restoration whenever desired. Endodontic access cavities are easily prepared and closed with composite, contact points are quickly adjusted and the surface is polished or re-polished in next to no time. Moreover, the wear properties are similar to those of tooth structure and patients are happy about a natural touch and feel. The aesthetic properties are quite impressive, too.

Dentist:

ENZO ATTANASIO

Enzo Attanasio graduated in 2008 in Dentistry and Dental Prosthetics from the Magna Graecia University of Catanzaro. In 2009, he went on to specialize in the use of laser and new technologies in the treatment of oral and perioral tissues at the University of Florence. That year he also attended Prof. Arnaldo Castellucci’s course in Clinical Endodontics at the Teaching Center of Microendodontics in Florence where, in 2012, he went on to complete his training in Surgical Microendodontics. In 2017 he attended a course on Direct and indirect Adhesive Restorations at Prof. Riccardo Becciani’s Think Adhesive training center in Florence where he later become a tutor. Today, as a member of the Italian AIC and based in Lamezia Terme, Italy, Dr Attanasio has a special interest in Endodontics and Aesthetic Conservative.

Clinical case by Dr. Frank Heldenbergh

The advancements in zirconia in contemporary dentistry nowadays allow for a wider range of applications, including in the anterior sector, and for chairside production using dedicated CAD/CAM systems. Even without a cutback, KATANA™ Zirconia Block (STML), combined with CERABIEN™ ZR FC Paste Stain (both Kuraray Noritake Dental Inc.), offer an extremely satisfactory aesthetic solution.

In the present patient case, the materials were chosen to replace old PFM crowns on the maxillary central incisors. The planned treatment was in accordance with the patient's wishes, and carried out in a single appointment.

CASE DESCRIPTION

The patient asked for a replacement of the existing crowns on the two maxillary central incisors (teeth 11 and 21, FDI notation). The porcelain-fused-to-metal (PFM) restorations had been in place for about thirty years (Figure 1). She desired aesthetic improvements and slight repositioning of these two teeth.

TREATMENT PLAN

In agreement with the patient, it was decided to perform the entire procedure in one appointment: removal of the existing crowns, digital impressions, production, and bonding of new restorations. The periodontium was healthy with no bleeding. The only uncertainty was whether the existing crowns were cemented onto inlay-cores or if they were Richmond crowns. A preliminary silicone impression was taken as a precautious measure: in case something unexpected prevented the new crowns from being bonded during the session, it would be easily possible to produce temporary crowns.

Fig. 1. Initial clinical situation.

TREATMENT

Using a diamond bur followed by a tungsten carbide bur, the existing crowns were removed, revealing that they indeed were Richmond crowns. Because the anatomy of the intra-radicular posts clearly contraindicates an attempt to remove these posts, it was decided to trim the crowns to transform them into inlay cores rather than risk further damage. The corono-peripheral preparations were reworked at the same time. One of the major challenges was related to the necessity of masking the metal of the transformed coronal-radicular reconstructions. Luckily, the space available was sufficient for the production of full zirconia crowns with a significant thickness (Figure 2). The target shade of the crowns was chosen in consultation with the patient (Figure 3).

Fig. 2. Situation after removal of the existing restorations.

Fig. 3. Shade determination using a shade tab: A2 was the appropriate shade.

Subsequently, impressions were taken using and intraoral scanner, the virtual models were checked and the crowns designed, considering the patient's request to have her two incisors slightly retracted (Figures 4 and 5).

Fig. 4. Virtual models of the patient’s teeth with the newly designed crowns, revealing the space available for a slight retraction.

Fig. 5. Designing of the two crowns.

The two crowns were milled from KATANA™ Zirconia Block 14Z A2 (Figure 6). A quick reminder: unlike lithium disilicate, zirconia prosthetic parts cannot be tried in immediately after milling, as they are around 20 percent larger than their final size after sintering. Final sintering was performed within about 18 minutes using the furnace SINTRA CS (ShenPaz Dental Ltd). After this process, the crowns may be tried on to check their fit, shape, shade and optical integration.

Fig. 6. Milled crowns in the CAD/CAM blocks.

For finishing of the restorations, different options are available. In this case, we decided not to limit ourselves to mechanical polishing of the prosthetic parts, as zirconia does not fluoresce like natural teeth. To add fluorescence as an optical feature, the surface was lightly stained and glazed with CERABIEN™ ZR FC Paste Stain (Figure 7).

Fig. 7. Crowns in the furnace after staining and glazing with liquid ceramics.

After firing, the two incisor crowns were tried in again using a try-in paste corresponding to the chosen resin cement system (PANAVIA™ V5, Kuraray Noritake Dental). In this way, the final appearance was simulated to validate the shade of the cement. The intaglio surfaces of the crowns were then sandblasted before applying CLEARFIL™ CERAMIC PRIMER PLUS as the restoration primer. The prepared teeth were treated with KATANA™ Cleaner (Kuraray Noritake Dental Inc.) to decontaminate the surface from proteins in saliva and possibly blood. Those clean surfaces are ideal for bonding. After thorough rinsing and drying, PANAVIA™ V5 Tooth Primer (containing MDP monomer for bonding with the hydroxyapatite and metal of the preparation) was applied according to the manufacturer’s instructions (Figure 8).

Fig. 8. Selected cementation system and try-in.

Subsequently, PANAVIA™ V5 Paste was applied into the first crown, which was then seated, followed by tack curing (brief photopolymerization for three to five seconds), excess removal and final light curing from all sides.

The procedure was then repeated for the second maxillary central incisor. The result instantly satisfied the patient, both in terms of aesthetics (adaptation, position of the new crowns, mimicry) and the comfort provided (Figures 9 and 10).

Fig. 9. Crowns immediately after placement.

Fig. 10. Aesthetically pleasing and comfortable result.

At a recall after four months, soft tissue conditions were ideal and the patient was happy with the outcome (Figures 11 to 13). The selected zirconia had nice optical properties, masking of the metal posts was successful and the natural surface texture contributed its share to a nice overall picture. The retracted position of the teeth was also perceived positively by the patient, while comfort and function were excellent.

DISCUSSION

Although lithium disilicate has so far been considered the material of choice for prosthetic work in the anterior region, zirconia is nowadays proving to be an extremely satisfactory alternative from every point of view: milling, strength, aesthetics, assembly (among other things, no hydrofluoric acid is required for bonding). KATANA™ Zirconia Blocks (STML) with a multi-layered colour structure in a single 4Y-TZP zirconia block, combined with CERABIEN™ ZR FC Paste Stain, offer a remarkable solution. This applies to treatments around the replacement of existing crowns as well as first-line treatments with less invasive preparations (verti-prep) than those required by other types of ceramics.

Fig. 11. The patient’s smile at a recall after four months.

Fig. 12. Great optical integration.

Fig. 13. Natural surface texture contributing to success Control pictures after four months taken by Emmanuel Charleux.

Dentist:

FRANK HELDENBERGH

Dr. Frank Heldenbergh graduated with a Doctor of Dental Surgery degree from the University of Reims in 1988.Driven by a passion for prosthetics, he pursued further specialization as a Prosthetic Resident at the UFR Odontology of Reims from 1990 to 1992. Dr. Heldenbergh’s dedication to advancing dental practices led him to join the Board of the Academy of Adhesive Dentistry in 1999. His commitment to this field has been unwavering, and he currently serves as the Vice President of A.D.D.A.-R.C.A.

Recognized for his expertise in ceramic veneers, inlays and onlays, Dr. Heldenbergh supervised practical work for the Paris Odontological Society from 2000 to 2018, shaping the skills of many aspiring dentists. His influence extended to the A.D.F. Congress, where he supervised practical work on ceramic veneers from 2000 to 2016. In 2017, he was the Head of Practical Work at A.D.F., a role that allowed him to further contribute to the advancement of dental education and practices. In 2018, he was the Head of Practical Work for ceramic veneers at the Paris Odontological Society.

Recognizing the importance of technology in modern dentistry, Dr. Heldenbergh pursued a University Degree in CAD/CAM from Toulouse in 2022. This addition to his qualifications highlights his dedication to staying at the forefront of dental innovation.

Case by Aleksandra Łyżwińska DMD, Warsaw, Poland

Dental injuries can be stressful for patients, parents of pediatric patients, and dentists alike. The following tips offer support in turning the treatment of crown fractures into a simple, quick and predictable procedure. In the case described, we opted for a reattachment of fractured crown fragments.

YOUNG PATIENT WITH A FRACTURED CENTRAL INCISOR

A 16-year-old patient presented immediately after an accident. Her maxillary left central incisor was fractured, involving half of the coronal enamel and dentin (Fig. 1). The pulp was not involved, but the fracture line was quite close to the pulp (Fig. 2). After examination and radiographic evaluation, the patient was anesthetized. When placing the rubber dam, it tore between the left central and lateral incisor (Figs. 3 and 4). Due to the patient’s young age and limited willingness to cooperate, the decision was made to proceed without replacing the rubber dam. This was expected to work well in this specific region due to the limited flow of saliva from the palate and a low associated risk of contamination.

Fig. 1. Fractured maxillary left central incisor at the day of the accident.

Fig. 2. Occlusal view of the maxillary anterior teeth with the pulp of the fractured central incisor shining through.

Fig. 3. Rubber dam placed and torn between the left central and lateral incisor.

Fig. 4. Occlusal view of the teeth isolated with rubber dam.

REMOVAL OF UNSUPPORTED ENAMEL PRISMS

In order to provide for a high-quality bond and natural aesthetics, unsupported enamel prisms should be removed. As the use of burs might be too invasive (removing too much structure) and thus hinder the alignment of crown fragments, air-abrasion with 50 μm alumina particles was the method of choice. To avoid iatrogenic pulp exposure, the deepest part of the affected tooth was protected with a colored flowable composite before sandblasting (Fig. 5). The adjacent teeth were protected using a metal strip (Fig. 6). Several seconds of air abrasion were sufficient to remove the enamel prisms and obtain a homogeneous enamel surface (Fig. 7). Subsequently, the colored flowable composite was removed from the dentin surface and the tooth fragment was treated in the same way.

Fig. 5. Preparations for sandblasting: Dentin area near the pulp protected with flowable composite.

Fig. 6. Protection of the adjacent teeth with a metal strip.

Fig. 7. Homogeneous enamel surface after air abrasion.

JOINING OF THE FRAGMENT WITH THE REMAINING TOOTH STRUCTURE

After air-abrasion treatment, the fit of the tooth and the fragment was checked and approved (Fig. 8). To improve retention of the fractured crown portion, it was bonded to a micro applicator using composite resin. Alternatively, prefabricated prosthetic carriers may be used. Then, selective etching of the enamel was performed on the tooth and the fragment (Figs. 9 and 10). During this procedure, the adjacent teeth were protected with a celluloid strip (Fig. 11). To better adapt the strip to the distal surface, a curved wedge was placed interproximally (Fig. 12).

The bonding system of choice was CLEARFIL™ SE Bond 2 (Kuraray Noritake Dental Inc.). After applying this adhesive to the tooth and the fragment (Fig. 13), a small portion of CLEARFIL MAJESTY™ ES Flow Super Low (Kuraray Noritake Dental Inc.) in the shade A2 was applied to the part of the fragment treated with adhesive.* After careful repositioning of the fragment and while holding it in place with the micro applicator, the composite was light cured.

Fig. 8. Perfect fit of the fragment to the tooth.

Fig. 9. Selective etching of the enamel on the tooth …

Fig. 10. … and the fragment.

Fig. 11. Position of the wedge …

Fig. 12. … used for better adaptation to the distal surface.

Fig. 13. Fragment treated with CLEARFIL™ SE Bond 2 PRIMER and BOND, which were both carefully air-dried, while the Bond was also light cured.

Fig. 14. Fragment back in place.

Fig. 15. Occlusal view of the teeth with the reattached fragment perfectly fitting the mould.

EXCESS REMOVAL AND POLISHING

Excess composite was removed with a scalpel blade and abrasive discs. The entire restoration was then polished using TWIST™ DIA for Composite (Kuraray Noritake Dental Inc., Fig. 16). A nice optical integration was obtained immediately after finishing due to fact that the fragment was stored in water during the waiting time and treatment. As observed with teeth isolated with rubber dam during treatment, teeth undergo dehydration outside the oral cavity. The effect is much stronger in the latter setting, making a fragment become chalky white. By keeping the fragment in water, dehydration is limited to a minimum and it is possible to properly evaluate the aesthetic outcome. This has a positive impact on patient satisfaction. In the present case, the fragment and the tooth structure had a similar appearance, both showing a slightly increased brightness as a result of manipulation under rubber dam or in the air, respectively.

Fig. 16. Immediately after polishing, the fragment has almost the same brightness as the tooth thanks to water storage. A slight dehydration effect is visible.

TREATMENT OUTCOME

To achieve optimal aesthetics and long-lasting gloss, the composite was repolished one week later (Fig. 17). This was accomplished with a light blue high-shine rubber polisher of the TWIST™ DIA for Composite system, followed by polishing with diamond paste and a goat hair brush.

Fig. 17. Treatment outcome after one week.

Teeth previously isolated with a rubber dam and the fractured crown fragment had undergone rehydration and returned to their natural colour. The colour adaptation is satisfactory. Harmonious light reflections on the labial surface of the treated tooth a beautiful, natural shine have made the fracture site nearly invisible. In addition to aesthetic value, good therapeutic results were also achieved - the tooth responds appropriately to stimuli and is pain-free.

CONCLUSION

The described approach is a valuable treatment option for anterior trauma cases with relatively large fragments that are still available. By reattaching the natural structure, the need for complicated and time-consuming multi-shade layering and free-hand modeling is eliminated, while all the remaining natural tooth structure is saved. Instead of preparing the tooth, a removal of the unsupported enamel prisms and roughening of the surface is absolutely sufficient. Key elements for a great optical integration and long-lasting success are the proper use of a high-performance adhesive as well as the selection of a composite that has the ability to properly blend into its environment and offers a nature-like gloss retention. The selected materials offer precisely these features, so that the great outcome may be expected to last.

*CLEARFIL MAJESTY™ ES Flow Super Low is indicated for cementation purposes. The cementation of tooth fragments, however, is not explicitly mentioned in the instructions for use. The decision to use the product in this context was made by the dental practitioner in charge of the treatment.

Dentist:

ALEKSANDRA ŁYŻWIŃSKA DMD

Aleksandra Łyżwińska graduated from the Medical University of Warsaw, where she later served as a lecturer and assistant in the Department of Conservative Dentistry with Endodontics. In her daily practice, she focuses on the broad field of adhesive dentistry. She is passionate about minimally invasive techniques and vital pulp therapy. Since 2020, she has been conducting courses in conservative dentistry, collaborating with major training centers in Poland and around the world. She is a key opinion leader for Kuraray Noritake. In her training sessions, she demonstrates that dental caries management doesn‘t have to be boring, and that the bond in the bottle is just as exciting as a spy movie. Instagram users know her as the creator of the educational profile for dentist @aleksandra.lyzwinska.

Technical Specialist for Chairside, Volkan Kacmaz, Introduces Himself

Volkan Kacmaz not only worked as a dentist in Turkey, but he also managed two clinics and earned a Master of Business Administration in Berlin. His diverse experiences seem to have led him to his current role as a Technical Specialist at Kuraray Noritake Dental Inc., headquartered near Frankfurt. Who is this friendly, smiley, and curious team member, and why did he specifically choose Kuraray?

While most dentists continue practicing dentistry throughout their careers, Volkan Kacmaz chose a different path. After graduating in 2011, he established his own dental clinic in Istanbul. A few years later, he served in the military for a year as a military dentist. Afterward, he founded two more franchise clinics, taking on the dual roles of manager and dentist. It was during this time that he realized dentistry wasn’t limited to clinical practice. “I’m eager to learn and have always been curious about how products work, the processes behind them, research and development, and the launch of new innovations,” he explains.

INNOVATION

In 2022, Kacmaz became the first dentist to enrol at the Berlin School of Economics and Law, where he learned about marketing, sales, negotiation, and regulations. Upon completing his Master of Business Administration, he made a deliberate decision to join Kuraray Noritake. “Kuraray Noritake's products are of very high quality, both labside and chairside. I already knew this from my experience as a dentist. The company has an excellent and trustworthy reputation among dental professionals,” he says.

Kacmaz also admires the innovative nature of the company. “Kuraray Noritake is responsible for some of the most significant innovations in dentistry. Just look at products like PANAVIA™ cement, the original MDP monomer, and multi-layered zirconia discs and blocks. It’s easy to see that Kuraray Noritake is a major force in the dental market. With their commitment to continuous improvement and innovation, you could call them the Apple of the dental world,” he adds.

Another aspect Kacmaz appreciates is Kuraray Noritake's product lineup. “The catalog isn't extensive, but it’s highly specialized. The company doesn’t produce just any product, but focuses on the ones it excels at, ensuring top-notch quality.” Lastly, Kacmaz loves the company culture. “It's a very respectful environment. I’ve had some bad experiences with respect in the past,” he says with a laugh, referring to his time in the military. “But at Kuraray Noritake, you can feel the respect for employees, which is very important to me. I’m very happy to be part of the Kuraray Noritake family.”

COURAGE

When comparing dentistry in Turkey to Western Europe, Kacmaz doesn’t see significant differences. “The brands, quality, and approaches are all the same.” However, he has noticed one small distinction: German dentists aren’t as enthusiastic about digital dentistry as their Turkish counterparts.

Kacmaz draws on all his previous experiences and knowledge in his role as part of the scientific marketing team. His responsibilities include finding scientific support for marketing initiatives. He collaborates with lecturers and dentists to manage research studies using Kuraray Noritake products, works to update measurements in response to market dynamics, and evaluates new products.

His goal? “To become an authority in the dental world,” he says with a smile. It may sound like an ambitious goal, but Kacmaz has learned to dream big. “The biggest decision of my life was leaving my comfort zone and moving to a country where I didn’t speak the language. But I believe it’s a courage you have to show. If you don’t, your dreams and plans will fade, and you’ll miss out on everything.”

LEARNING NEW THINGS

Moving to Germany, which Kacmaz describes as "the epicentre of the dental market," hasn’t always been easy. Coming from a Mediterranean culture, he was used to a more communal and lively environment. In Germany, he noticed that shops close early, and people value their privacy. Another challenge has been the language. While he prefers English, he says, “ein bisschen Deutsch, nicht so gut.”  Fortunately, Kuraray Noritake provides him with German lessons, and he has the best teacher at home—his three-year-old daughter, who learns the language faster than he does and sometimes corrects him.

Despite the challenges, all the adapting and hard work have been worth it. “I’ve realized that there are no limits to learning. Whether you’re in your 40s, 50s, or even 60s, there’s always something new to discover. You just have to be open to it.”

CONTACT

Volkan Kacmaz can be reached at +49 69 305 35134 or via volkan.kacmaz@kuraray.com.

ABOUT KURARAY NORITAKE DENTAL INC.

Kuraray was founded in 1926 in Kurashiki, Japan. Today, it is a leading global manufacturer of medical products, materials, textiles, chemicals, resins, and more. In 2012, Kuraray Medical and Noritake Dental Supply merged to form Kuraray Noritake Dental Inc. The company continues to deliver reliable dental bonding agents, ceramics, and other products to over 90 countries worldwide. Well-known products include the KATANA™ Zirconia range, CLEARFIL™ Universal Bond Quick, and PANAVIA™ resin cements.

Case by Dr. Jusuf Lukarcanin

For all cases that require a particularly bright tooth shade – e.g. children or patients with bleached teeth / asking for a bleached effect in their restorations – CLEARFIL MAJESTY™ ES-2 Universal in the shade UW is likely to be the first choice. The young patient aged 28 shown below asked for diastema closure including shape and shade correction: She wanted to have a brighter, more beautiful smile.

Fig. 1. Initial clinical situation.

Fig. 2. Shape and shade correction were desired in this case.

Fig. 3. Treatment outcome …

Fig. 4. … leading to the beautiful smile the patient desired.

Reasons for selecting universal white:

- Cases requiring a particularly high brightness or value

- Restorations in deciduous teeth

- Restorations in bleached teeth

Universal white properties:

- Well-balanced translucency

- High light-scattering effect

CONCLUSION

One universal composite, four shades: In the case of CLEARFIL MAJESTY™ ES-2 Universal, this portfolio is absolutely sufficient for single-shade restorations even in the aesthetically demanding anterior region. Properties such as a nice blend-in effect, a great polishability and gloss retention over time support dental practitioners in creating beautiful restorations. As shade determination may be based on very few criteria instead of a complex shade guide, the whole restoration procedure becomes less stressful and more efficient. Furthermore, with only four shades to stock and usually no blocker needed, the number of materials on stock is reduced, leading to facilitations in stock management as well.

Dentist:

JUSUF LUKARCANIN

Dr. Jusuf Lukarcanin is a Certified Dental Technician (DCT) and a Doctor of Dental Science (DDS). He studied dentistry at the Ege University Dental Faculty in Izmir, Turkey, where he obtained a Master‘s degree in 2011. In 2017, he received a Ph.D. degree from the Department of Restorative Dentistry of the same university. Between 2012 and 2019, Dr. Lukarcanin was the head doctor and general manager at a private clinic in Izmir.

Between 2019 and 2020, he worked at Tinaztepe GALEN Hospital as a Restorative Dentistry specialist, between 2020-2022 he worked at MEDICANA International Hospital Izmir as a Restorative Dentistry specialist. Currently he is an owner of a private clinic for aesthetics and cosmetics in Izmir.

Some companies mainly make use of basic technologies developed by others to improve their products and introduce new ones, while other companies conduct fundamental research and technology development inhouse. Is this difference relevant for someone who uses the resulting products in the dental practice or laboratory on a daily basis? It is – as companies with a deep understanding of the underlying components, chemistry and technologies are able to solve existing problems and respond to market needs flexibly and quickly. This article describes the impact of several basic technologies developed by Kuraray Noritake Dental Inc. on the cementing of indirect restorations.

Adhesive cementation then and now

The possibility of milling dental restorations from different kinds of ceramics has opened up new opportunities in prosthodontics: highly aesthetic restorations can be produced and placed. What is often undervalued in this context is the role of adhesive cementation systems, which not only support the aesthetic appearance of the translucent, tooth-coloured restorations, but also pave the way for less invasive preparation and restoration designs. Early systems that provided for chemical adhesion between teeth and indirect restorations unfortunately offered a compromised long-term behaviour and high technique-sensitivity, while the application procedure was extremely complex. Technology development at Kuraray Noritake Dental Inc. made significant contributions to an improved long-term bonding performance of the systems and a simplified handling.

Optimizing the long-term bonding performance

In order to achieve long-term bonding of early cementation systems to tooth structure (especially dentin), Kuraray, a parent company of Kuraray Noritake Dental Inc., decided to focus on the development of a more powerful adhesive monomer in the 1970s. As a first step on its road to excellence, it introduced the phosphate monomer Phenyl-P in 1976. Five years later, continued efforts in improving and refining its molecular structure led to the introduction of the popular MDP Monomer that is capable of establishing a particularly strong and long-lasting bond to enamel, dentin, metal and zirconia.

The fact that it is still part of every adhesive and adhesive cementation system from Kuraray Noritake Dental Inc., and meanwhile also used by other manufacturers to optimize the bond strength and bond durability of their products, stresses the ingenuity of the invention. Compared to MDP synthesized elsewhere, the Original MDP Monomer from Kuraray Noritake Dental Inc. stands out due to an unmatched level of purity. Independent Studies show that this level of purity has a positive effect on its bonding behaviour¹. By offering stability in a moist environment, the MDP Monomer has contributed to a more consistent performance of the products containing it.

Different MDP Monomers offer different levels of purity and a different bonding performance.

Three experimental self-etch primers were prepared consisting of 15 wt.% 10-MDP provided by different sources: KN (Kuraray Noritake Dental), PCM (Germany) or DMI (Designer molecules Inc., USA). Data courtesy of Dr. Kumiko Yoshihara.

For adhesive resin cement systems to deliver a strong bond with an outstanding marginal seal, however, simply containing an adhesive monomer is not enough. Effective polymerization of this monomer is necessary as well – and not always that easily accomplished. In order to provide for an effective light-cure and dark-cure performance of PANAVIA™ V5, Kuraray Noritake Dental Inc. developed the Touch-Cure Technology. The key part of this technology is a newly developed, highly-active polymerisation accelerator in PANAVIA™ V5 Tooth Primer that is able to coexist with the acidic MDP Monomer promotes polymerisation starting from the interface between the tooth and the cement as soon as PANAVIA™ V5 Paste is applied to the already primed tooth surface. In PANAVIA™ Veneer LC – a light-curing resin cement system that works with the same primers – the polymerisation accelerator in PANAVIA™ V5 Tooth Primer shows the same mechanism of action. It contributes to the polymerization of the adhesive interface, while PANAVIA™ Veneer LC Paste offers excellent ambient light stability and is polymerized by light curing.

For example, this phenomenon was evaluated for PANAVIA™ F2.0, the predecessor of PANAVIA™ V5. The result of the study: PANAVIA™ F2.0 showed much better marginal sealing properties than other cement systems evaluated². This documented secure sealing of the interface leads to a lower incidence of marginal leakage, to a very high polymerisation ratio even in the self-cure mode (without light curing or wherever the light is blocked by the restorative material) and hence to a particularly strong bond.

An additional benefit arising from the incorporation of the polymerisation accelerator is its function as a strong reductant. It neutralizes sodium hypochlorite, which is commonly used as an irrigation solution during endodontic treatment, and thus eliminates its negative effect on the bond strength of the subsequently applied cement paste.

A highly active polymerisation accelerator in PANAVIA™ V5 Tooth Primer promotes effective polymerisation of the cement at the adhesive interface.

Simplifying glass-ceramic cementation

Fewer bottles, fewer steps and streamlined cementation procedures: that is why self-adhesive resin cements have been developed and introduced in the early 2000s. Most of these products, however, have a limited indication range. They work well on zirconia, metal, enamel and dentin, but are either not recommended or need an extra silane primer for glass-ceramic bonding. The MDP-containing PANAVIA™ SA Cement Universal is different due to another proprietary technology from Kuraray Noritake Dental Inc.: the LCSi Monomer, a Long Carbon-chain Silane coupling agent. This monomer forms a strong chemical bond with resin composite, porcelain and silica-type ceramics (like lithium disilicate), so that the need for a separate silane component (a primer or adhesive) is eliminated. By leveraging the benefits of this technology, PANAVIA™ SA Cement Universal clearly sets itself apart from other self-adhesive resin cements as a true single-component cementation system even for restorations made of glass ceramics.

If desired, the product’s bond strength to tooth structure can be increased by use of the popular universal adhesive CLEARFIL™ Universal Bond Quick featuring Rapid Bond Technology. This technology has been developed by Kuraray Noritake Dental Inc. to solve problems related to the slow penetration of tooth structure, especially wet dentin, typical for universal adhesives. In order to provide proper penetration, these adhesives need to be actively rubbed into the tooth structure for a long time or users have to wait for some time before light-curing the layer. Consisting of the Original MDP monomer combined with hydrophilic amide monomers, the proprietary Rapid Bond Technology provides for a high affinity to water leading to a rapid and deep penetration of wet dentin. As a consequence, application times are shortened and handling is simplified without negatively affecting the bonding performance.

Conclusion

Technologies developed by Kuraray Noritake Dental Inc. have strongly contributed to an improved bonding performance of adhesive cementation systems and a truly universal use of self-adhesive resin cements. As a consequence, the company offers a streamlined portfolio of high-performance resin cements for every user, for the typical clinical situations. Fewer components and fewer steps are necessary and procedures simplified – for fewer errors and aesthetic restorations that last. Apart from the technology-related benefits, the products mentioned offer many additional beneficial features. A detailed description is found online at kuraraynoritake.eu.

References

1) Functional monomer impurity affects adhesive performance.; Yoshihara K, Nagaoka N, Okihara T, Kuroboshi M, Hayakawa S, Maruo Y, Nishigawa G, De Munck J, Yoshida Y, Van Meerbeek B. Dent Mater. 2015 Dec;31(12):1493-501.
2) Touch-Cure Polymerization at the Composite Cement-Dentin Interface.; Yoshihara K, Nagaoka N, Benino Y, Nakamura A, Hara T, Maruo Y, Yoshida Y, Van Meerbeek B.J Dent Res. 2021 Aug;100(9):935-94.