We are proud and delighted to announce that Kuraray Noritake Dental has been honored as the INNOVATIVE COMPANY OF THE YEAR by DENTAL ADVISOR.

DENTAL ADVISOR conducts annual practice-based clinical evaluations and product performance tests. The results are published online in the January/February issue, aiding potential users in identifying high-quality new dental materials and selecting those best suited to their individual requirements.

Quoting DENTAL ADVISOR: “Kuraray Noritake was chosen as innovative company of the year because of their constant ability to adapt to market needs and change. Their products are universally accepted by dental professionals as market leaders due to their ease of use and consistently high laboratory performance, making them ideal choices for long-term clinical results.”

In addition to being recognized as an innovative company, our products underwent testing and received prestigious DENTAL ADVISOR medals:

• CLEARFIL MAJESTY™ ES Flow (Low) received the Top Product Award for the 9th consecutive year in the Highly-Filled Flowable Composites category.
• CLEARFIL™ SE Protect, a Top Product Award winner in the Self Etch Bonding Agent category, has held this honor for the 10th consecutive year.
• Our very own PANAVIA™ SA Cement Universal secured the Self-Adhesive Cement category win.
• CLEARFIL™ Universal Bond Quick was honored with the Preferred Product Award in the Universal Bonding Agents category.
• Lastly, our most recent cement, PANAVIA™ Veneer LC, received the Research Award.

We extend our heartfelt gratitude to the dedicated practitioners worldwide who have placed their trust in Kuraray Noritake Dental products. Your unwavering commitment to excellence fuels our ongoing pursuit of innovation and quality. We are honored to stand alongside you in advancing dental care, and we look forward to continuing this journey together.

Thank you for choosing Kuraray Noritake Dental – where innovation meets trust, and quality meets precision.

2024 MARKS THE YEAR OF THE DRAGON

• Dragons, those mythical beings, embody innate courage, unyielding tenacity, and boundless intelligence. They fearlessly embrace challenges and eagerly venture into uncharted territories.
• The Year of the Dragon is hailed as a time of great power, auspicious beginnings, and transformative possibilities.
• This image, inspired by the traditional Japanese art of kirigami, combines age-old craftsmanship with cutting-edge AI technology. Just like the dragon, it represents a harmonious blend of ancient wisdom and modern innovation.

EMBRACE 2024 WITH OPEN ARMS –
IT BRINGS FORTH A YEAR OF NEW POSSIBILITIES

It is probably the best-known component of a dental product Kuraray Noritake Dental Inc. (Kuraray Noritake Dental) has ever developed: 10-Methacryloyloxydecyl Dihydrogen Phosphate, in short, the MDP monomer. Invented more than 40 years ago – the first product containing it was introduced in 1983 – MDP is still the leading functional monomer used to establish a long-term, durable and stable bond to hydroxyapatite in tooth structure and to metal oxides in restorative materials (oxide ceramics and metal alloys).

Nowadays, it is found in every dental adhesive and every component of a resin cement system with adhesive properties from Kuraray Noritake Dental. These include:

In addition, MDP has become an integral part of most universal adhesives and many adhesive cementation systems of other manufacturers as well. However, not all MDP is alike …

MDP: Chemical structure and mechanism of adhesion

The MDP monomer consists of three essential parts: A polymerizable group, a hydrophobic group and a hydrophilic group. The co-polymerizable methacrylate group has a terminal double bond enabling polymerisation. The large hydrophobic alkylene group – also referred to as the spacer – has the task to maintain a delicate balance between hydrophobic and hydrophilic properties of the monomer and offers great resistance to degradation. Finally, the hydrophilic phosphate group is responsible for acidic demineralisation, for chemical bonding with calcium in hydroxyapatite and for bonding with zirconia¹ (as well as with metal).

Bonding performance

Lots of in-vitro studies have been carried out to investigate the bonding behaviour of 10-MDP in the context of direct and indirect restorative procedures. No matter whether a cavity is to be filled with resin composite or an indirect restoration is to be placed, a strong and long-lasting bond to tooth structure needs to be established.Chemical structure of adhesive monomer 10-Methacryloyloxydecyl Dihydrogen Phosphate (MDP).

The critical substrate in this context is dentin, while bonding to enamel is found to be less challenging. That is why it is so important that (self-etch) adhesives containing 10-MDP show an extraordinarily high bond strength to tooth structure, particularly to dentin². In fact, 10-MDP also provides for a high bond stability over time by establishing an acid-base resistant zone on the adhesive interface³. This means that a great long-term performance may be expected. Fortunately, a great clinical long-term performance of products containing the MDP monomer has already been confirmed: A group from the University of Leuven (Belgium) has presented excellent results of a thirteen-year clinical trial involving the use of CLEARFIL™ SE Bond in 2015⁴.

When bonding to indirect restorations made of zirconia, the surface area of the ceramic should be increased by sandblasting⁵. Pre-treated in the recommended way, the bond strength to zirconia tends to be particularly high when MDP-based resin cement systems are used⁶. It is thus widely recommended by experts in the field of adhesive dentistry to employ MDP-containing primers or resin cements for the placement of zirconia-based restorations, especially those with a non- or less retentive preparation. The fact that products containing 10-MDP work well in this context has been confirmed in different clinical studies with observation periods of up to 10 years^7,8. The products used in these studies were PANAVIA™ 21, PANAVIA™ F2.0 and the latest version of the multi-component cementation system from Kuraray Noritake Dental, PANAVIA™ V5, which performed best.

Not all MDP is alike

Ever since the basic patent for MDP has expired, other manufacturers of dental adhesives and adhesive resin cements have started integrating the functional monomers in their own products. However, it has been revealed that there are differences in the purity of the MDP monomers synthesized and used, and that these differences have an impact on the long-term bonding performance of the products containing the MDP⁹. According to in-vitro test results, the Original MDP Monomer synthesized by Kuraray Noritake Dental stands out due to an unmatched level of purity. This purity has a positive effect on the microstructure and thickness of the hybrid layer formed on dentin, the intensity of nano-layering and the bond strength measured immediately as well as after artificial aging⁹.

Conclusion

The data summarized above reveals that after 40 years in clinical service, the Original MDP Monomer from Kuraray Noritake Dental is still a class of its own. It has everything needed to establish a strong and long-lasting bond to tooth structure, resin composite and metal oxides, and is therefore a valuable component in virtually every adhesive system. In order to provide for a high bond quality, however, it may be best to use an MDP monomer with a confirmed high purity – the Original MDP Monomer.

References

1. Nagaoka N, Yoshihara K, Feitosa VP, Tamada Y, Irie M, Yoshida Y, Van Meerbeek B, Hayakawa S. Chemical interaction mechanism of 10-MDP with zirconia. Sci Rep. 2017 Mar 30;7:45563.
2. Fehrenbach J, Isolan CP, Münchow EA. Is the presence of 10-MDP associated to higher bonding performance for self-etching adhesive systems? A meta-analysis of in vitro studies. Dent Mater. 2021 Oct;37(10):1463-1485.
3. Carrilho E, Cardoso M, Marques Ferreira M, Marto CM, Paula A, Coelho AS. 10-MDP Based Dental Adhesives: Adhesive Interface Characterization and Adhesive Stability-A Systematic Review.
4. Peumans M, De Munck J, Van Landuyt K, Van Meerbeek B. Thirteen-year randomized controlled clinical trial of a two-step self-etch adhesive in non-carious cervical lesions. Dent Mater. 2015 Mar;31(3):308-14.
5. Kern M, Barloi A, Yang B. Surface conditioning influences zirconia ceramic bonding. J Dent Res. 2009; 88: 817–822.
6. Özcan M, Bernasconi M. Adhesion to zirconia used for dental restorations: a systematic review and meta-analysis. J Adhes Dent. 2015 Feb;17(1):7-26.
7. Kern M, Passia N, Sasse M, Yazigi C. Ten-year outcome of zirconia ceramic cantilever resin-bonded fixed dental prostheses and the influence of the reasons for missing incisors. J Dent. 2017 Oct;65:51-55.
8. Bilir H, Yuzbasioglu E, Sayar G, Kilinc DD, Bag HGG, Özcan M. CAD/CAM single-retainer monolithic zirconia ceramic resin-bonded fixed partial dentures bonded with two different resin cements: Up to 40 months clinical results of a randomized-controlled pilot study. J Esthet Restor Dent. 2022 Oct;34(7):1122-1131.
9. Yoshihara K. et al. Functional monomer impurity affects adhesive performance. Dent Mater. 2015 Dec;31(12):1493–1501.

Is it safe to use the single-component PANAVIA™ SA Cement Universal to lute virtually all your indirect restorations?

Did you ever ask yourself how many components are really needed to safely cement your silicate-ceramic, zirconia or resin-based restorations? With PANAVIA™ SA Cement Universal, a single component is usually sufficient. Containing an unreacted silane coupling agent – the LCSi monomer – and the original MDP monomer, the dual-cure, self-adhesive resin cement adheres to tooth structure and to various restorative materials including the popular silica-based ceramics without the need for a separate primer.

For those wondering how it works and if it really works as well as desired, Kuraray Noritake Dental Inc. has created a scientific brochure. It contains in-depth information about the drivers of chemical adhesion contained in PANAVIA™ SA Cement Universal and its characteristic properties. The main part, however, focuses on the results of scientific studies – most of which have been conducted in external laboratories. With the aid of artificial aging, different testing devices and various experimental set-ups, the researchers have checked the resin cement thoroughly. The study results shed light on the behaviour of the material when used in the context of bonding to different restorative materials and different types of tooth structure. Self- and light-curing modes are compared, aging effects investigated and different moisture conditions taken into account.

As a whole, the collected data allows for a precise prediction of the clinical behaviour of PANAVIA™ SA Cement Universal. This valuation has already been confirmed by clinical experience of dental practitioners from all around the world. Moreover, the results of a first clinical study, which is also found in this compilation, are a proof of its exceptional performance.

Download the brochure to learn more about the properties and behaviour of the single-component universal resin cement!

VOUS ÊTES-VOUS DÉJÀ DEMANDÉ POURQUOI LES PRODUITS DE LA MARQUE PANAVIA™ OFFRENT D‘AUSSI BONNES PERFORMANCES?

Vous savez probablement qu‘ils contiennent tous le monomère MDP original développé au début des années 1980. Ce monomère adhésif a beaucoup fait parler de lui pour son excellence. Monomère d‘ester de phosphate, il forme une très forte adhésion à la structure dentaire, à la zircone et aux métaux dentaires. Il a été utilisé dans chaque produit PANAVIA™. Outre le MDP, d‘autres technologies et ingrédients catalytiques sont d‘importants contributeurs qui soutiennent les performances de nos solutions de collage.

INGRÉDIENTS INFLUANÇANT LA RÉACTION DE POLYMÉRISATION

Parmi ces autres technologies et ingrédients déterminants, notons le catalyseur qui provoque le processus de polymérisation. Différent du monomère MDP utilisé dans chaque produit PANAVIA™, le catalyseur de polymérisation a été amélioré en permanence depuis l’introduction de PANAVIA™ EX en 1983. Ainsi, de nouvelles versions ont été développées pour PANAVIA™ 21, PANAVIA™ Fluoro Cement et PANAVIA™ V5, entre autres. Un autre important composant qui influence également le processus de polymérisation est la Touch Cure Technology utilisée dans deux des trois principaux produits de la ligne PANAVIA™ actuelle : PANAVIA™ V5 et PANAVIA™ Veneer LC. Cette technologie est intervenue pour la première fois dans PANAVIA™ 21, qui a été lancé en 1993. Lorsque l’activateur chimique de polymérisation contenu dans l’apprêt à auto-mordançage entre en contact avec la pâte de ciment de résine, la polymérisation de la colle de l’interface adhésive est accélérée, apportant ainsi une meilleure adhésion du ciment de résine. En développant PANAVIA™ V5, nous avons revu et actualisé considérablement la composition chimique des produits PANAVIA™ existants. La Touch Cure Technology a également été adoptée pour le cas d’une utilisation de PANAVIA™ V5 Tooth Primer en concomitance avec PANAVIA™ V5 Paste. Pour coller des facettes avec PANAVIA™ Veneer LC, nous utilisons aussi PANAVIA™ V5 Tooth Primer afin de préparer les dents. Cet apprêt recourt lui aussi à la Touch Cure Technology pour obtenir une connexion adhésive avec la dent sans affecter le temps de travail de la pâte de ciment.

MONOMÈRES ADHÉSIFS ADDITIONNELS

Dans le domaine des monomères adhésifs également, nous n’avons pas ménagé nos efforts : Nous avons développé le monomère LCSi, un agent combinant le silane à longue chaîne carbonée qui a permis d’intégrer la fonction d’un apprêt céramique à notre ciment de résine auto-adhésif universel PANAVIA™ SA Cement Universal. Avec son degré élevé d’hydrophobie, ce monomère apporte une force d’adhésion stable sur le long terme. D’une manière générale, on peut dire que la durabilité d’adhésion peut baisser en raison d’une réaction hydrolytique endommageant l’adhésion chimique entre la silice contenue dans la vitrocéramique et l’agent combinant le silane.

TROIS PRODUITS COUVRANT PRATIQUEMENT TOUS LES BESOINS

En combinant intelligemment ces technologies et ingrédients, nous avons réussi à développer une gamme de ciments de résine qui couvre pratiquement tous les besoins. Avec PANAVIA™ V5, PANAVIA™ SA Cement Universal et PANAVIA™ Veneer LC, il est possible de traiter une grande variété de cas. Ces produits permettent l’assemblage de nombreux types de restaurations, d’appareils prothétiques et la pose de tenons pour offrir d’excellents résultats à condition d’être utilisés conformément aux consignes d’utilisation.

PANAVIA™ V5 est le ciment de résine offrant le champ d’utilisation le plus vaste parmi les trois systèmes de collage que nous venons d’évoquer. Il couvre pratiquement toutes les utilisations visées par les deux autres ciments. C’est pourquoi le praticien dentaire peut, en fonction des cas se présentant à la clinique et des besoins des patients, trouver le bon système de collage pour le traitement en choisissant parmi ces trois principaux produits de ciment de résine : PANAVIA™ V5, un ciment de résine avec un vaste champ d’applications, PANAVIA™ SA Cement Universal, un ciment de résine auto-adhésif simple et facile à manipuler et PANAVIA™ Veneer LC quand il s’agit d’adhésion de facettes stratifiées.

EXPLORER DE NOUVELLES OPPORTUNITÉS

L’avantage du développement de technologies au sein d’une société telle Kuraray Noritake Dental est que leur application ne se limite pas à un certain produit ou groupe de produits. Le département R&D étudie toujours comment tirer profit des bénéfices de ces technologies pour d’autres applications. C’est le cas par exemple pour KATANA™ Cleaner, qui a été mis sur le marché en 2019. Ce nettoyant peut être utilisé pour éliminer la salive, le sang, la colle provisoire et d’autres contaminants qui peuvent adhérer aux surfaces des dents ou des appareils prothétiques pendant les essayages et le collage provisoire d’une prothèse. Ce produit unique a été développé en exploitant la fonction tensioactive du monomère MDP.

CONCLUSION

L’excellence de la gamme PANAVIA™ actuelle découle principalement de nos connaissances et de notre expérience de longue date dans le développement de ciments de résine et solutions adhésives dentaires. Nous savons comment améliorer nos technologies existantes, ne cessons jamais d’en développer de nouvelles et recherchons continuellement la meilleure façon de combiner les composants éprouvés avec les nouveaux pour obtenir le meilleur résultat possible. Au fil des étapes de la procédure de développement de produits, des tests cliniques sont réalisés et les retours de praticiens dentaires sont recueillis afin de prendre en compte les conditions extrêmes dans l’environnement bucco dentaire. Cette stratégie a brillamment fait ses preuves tout au long des 40 dernières années, et nous sommes convaincus qu’elle nous aidera à développer de nombreux autres produits innovants qui offrent un soutien idéal dans nos efforts pour améliorer la santé bucco-dentaire des patients.

ADHESIVE LUTING: A DRIVER OF INNOVATION

What would modern restorative treatments be like without the availability of high-performance (self-)adhesive resin cements? Tooth preparations would still be much more invasive due to the need for sufficient mechanical retention between the tooth and the restoration. At the same time, it would be impossible to restore teeth with many innovative, tooth-coloured materials such as low-strength ceramics and composite. In short, restorative dentistry would be much less developed than it is today.

When the first resin cements were introduced several decades ago, however, the achieved progress came at the expense of simplicity: Adhesive luting procedures were highly complex and the many different components quite technique sensitive. Luckily, this has changed over the years due to continued development efforts ultimately resulting in the products that are currently available. The resin cement line-up of Kuraray Noritake Dental Inc. consists of three main products: the dual-cure three-component system PANAVIA™ V5, the single-component dual-cure universal resin cement PANAVIA™ SA Cement Universal and the light-curing PANAVIA™ Veneer LC.

For those who would like to learn more about the three systems, this 10^th issue of the BOND Magazine is definitely worth reading. It reveals important details about the 40-year history of the PANAVIA™ brand, sheds light on the strengths of each resin cement to facilitate indication-specific cement selection and provides in-depth information about their clinical use. In addition, two articles are dedicated to hot topics around the luting of restorations made of zirconia, a popular restorative material that some still consider to be unsuitable for adhesive luting procedures. For everyone wondering how it is possible to successfully lute minimally invasive restorations made of zirconia, the article titled “Innovative resin cements forming the basis of minimally invasive prosthodontics” is highly recommended. Those unsure about how to proceed with 5Y-TZP should read the article “How to cement restorations made of high-translucency zirconia”. Interesting information about cleaning options prior to adhesive luting rounds out the content of this magazine.

Click here to read. Enjoy reading!

Start Reading: BOND | VOLUME 10 | 10/2023

Previous versions:

BOND | VOLUME 9 | 08/2022

BOND | VOLUME 8 | 12/2021

BOND | VOLUME 7 | 10/2020

Photo credits to Giuliano Moustakis

Can you imagine a world without multi-layered zirconia? The invention of a zirconia material with natural colour gradation and well-balanced translucency and strength led to fundamental changes in the way zirconia-based restorations are produced. When the first product of its kind – KATANA™ Zirconia ML – was introduced to the dental market exactly ten years ago, dental technicians all over the world suddenly started rethinking their manufacturing concepts.

Since then, the trend towards a decreased thickness of the porcelain layer, a limiting of this layer to the vestibular area and the production of monolithic restorations is clearly perceivable. Technicians have developed their own concepts of micro-layering, which allow for more patient-centred approaches. This is also due to the fact that the total wall thicknesses of the restorations may be decreased without compromising the aesthetics. The line-up of multi-layered zirconia currently available from Kuraray Noritake Dental Inc. (KATANA™ Zirconia UTML, STML, HTML Plus and KATANA™ Zirconia YML with additional translucency and strength gradation) enables users to make indication-related material choices for the production of restorations that are precisely aligned to the individual demands of each case.

The reasons to choose KATANA™ quality

But why choose KATANA™ Zirconia instead of any other multi-layered zirconia disc? According to experienced users of the KATANA™ Zirconia Multi-Layered series, there are many reasons to opt for KATANA™.

For Jean Chiha, owner at North Star Dental Laboratories and Milling Center in Santa Ana, California, it is the combination of optical and mechanical properties that makes the difference: 

“KATANA™ Zirconia is the game changing material with well-balanced esthetics and strength!”. 

Naoki Hayashi, president of Ultimate Styles Dental Laboratory in Irvine, California, aesthetics is the most decisive argument to opt for the discs from Kuraray Noritake Dental Inc. He states:

“KATANA™ Zirconia discs offer trusted esthetics which gives me confidence in my clinical cases”.

Naoto Yuasa, chief ceramist at Otani Dental Clinic in Tokyo, adds predictability as an important factor:

“KATANA™ sustains my passions for aesthetic restorations and those of a predictable future in the long run”, whereas dependability is the key element.

For Hiroki Goto, the laboratory manager at Sheets and Paquette Dental Practice in Newport Beach, California reports:

“Without KATANA™ there is no pride. Haven’t experienced it yet? You have to see how reliable it is!”

Finally, we have asked Kazunobu Yamada, a pioneer in making porcelain laminate veneers using complementary color techniques and a first-hour user of KATANA™ Zirconia, what comes to his mind when thinking about KATANA™ Zirconia. According to the president of CUSP Dental Laboratory in Nagoya City, there is a clear link between the product name and its characteristics:

“Did you know that the word "KATANA" also means "protection against misfortune and evil"? Katana zirconia, the culmination of many years of research and development by Kuraray Noritake, has an unparalleled quality. KATANA™, for me, is truly "Protection for all technicians".”

The origin of well-balanced properties

It seems that the KATANA™ Zirconia Multi-Layered line-up stands out due to set of valuable properties enabling a dental technician to produce beautiful, high-quality restorations every time. The secret of success lies in meticulous raw material selection and controlled processing from the powder to the pre- sintered blank carried out at the production facilities of Kuraray Noritake Dental Inc. in Japan. They provide for the high product quality that is responsible for the materials’ outstanding behaviour supporting the best possible outcomes.

Case by Kanstantsin Vyshamirski

A male patient (47 years of age) presented to his dentist with severe damage to his teeth. His main request was to increase aesthetics, to achieve a more pleasing envisaged aesthetic area. A side request was to achieve a ‘whitening but natural look’. This was achieved by using a lighter colour palette of zirconia and porcelain materials. The final result was achieved through the creation of a wax-up, followed by a mock-up, provisional restoration and finally adhesive bonding of the zirconia crowns.

Initial situation

Fig. 1. Initial situation. Male patient (47 years of age)

Fig. 2. Planning the new smile according to patient’s aesthetic and functional parameters.

Fig. 3. Mock-up in place to check the new look in the patient’s mouth.

Fig. 4. KATANA™ Zirconia YML shade A1 crowns with labial cutback after milling.

Fig. 5. Crowns after sintering on on the plaster model.

Fig. 6. Noritake CERABIEN™ ZR porcelain layering map.

Fig. 7. Finishing the labial surface using both polishing and selfglaze. On the palatal side of the crowns only CERABIEN™ FC Paste Stain stains and glaze were used for finishing. To aid in optimisation of the soft tissue condition the palato-cervical and near proximal areas were polished.

Fig. 8. Finished crowns on the plaster model.

Fig. 9. Try-in using PANAVIA™ V5 White try-in paste, to confirm the proper appearance. For the final adhesive cementation PANAVIA™ V5 White has been used.

Final situation

Fig. 10. Situation after seven months. The result is aesthetically pleasing and the gingival condition excellent.

Fig. 11. Recall after 1.5 years

Click here for the product page for more details

What can you expect to find online

- General information about:
- KATANA™ Zirconia YML
- CERABIEN™ ZR porcelains
- FC Paste Stain
- PANAVIA™ V5
- Full Product Assortment
- Safety Data Sheets
- Instructions For Use
- Technical Information

Kanstantsin started his dental technician career in 2014. His speciality is aesthetic prosthetic porcelain works. Kanstantsin is an experienced user of KATANA™ Zirconia and Noritake porcelains. He owns his lab in Riga, Latvia.

Certaines entreprises utilisent principalement des technologies de base développées par d‘autres afin d‘améliorer leurs produits et d‘en introduire de nouveaux, alors que d‘autres sociétés mènent des recherches fondamentales et développent la technologie en interne. Cette différence est-elle importante pour ceux qui utilisent les produits en résultant au cabinet ou laboratoire dentaire au quotidien ? C‘est le cas - étant donné que les entreprises qui développent tout à partir de rien disposent généralement d‘une compréhension plus approfondie des produits et de leurs procédures de production, ce qui leur permet de modifier plus facilement certaines caractéristiques, de résoudre certains problèmes et de répondre aux besoins sur le marché. Cet article décrit l‘impact de plusieurs technologies de base développées par Kuraray Noritake Dental Inc. concernant le flux de travail associé à la création de restaurations composite directes.

Les restaurations directes - de la complexité à la simplicité

La dentisterie restaurative adhésive utilisant des adhésifs dentaires et résines composites haute performance est actuellement l‘un des plus populaires traitements des dents avec lésions carieuses. De nos jours, un flacon unique d‘adhésif universel et une ou deux nuances et opacités de composite universel suffisent généralement pour obtenir des résultats esthétiques et durables, à condition de sélectionner les bons matériaux. Toutefois, cela n‘a pas toujours été le cas. Pendant longtemps, les techniques utilisées pour créer des restaurations directes étaient assez complexes : les adhésifs étaient des flacons multiples sensibles à la technique appliquée et des systèmes à étapes multiples avec des temps d‘application longs. D‘un autre côté, les matériaux de charge composites ne produisaient des résultats naturels qu‘à grands renforts de nuances et opacités différentes et combinées correctement. Et, même lorsque les procédures complexes étaient mises en oeuvre correctement, le risque de microfuite, décoloration et caries secondaires au final était relativement élevé. Kuraray Noritake Dental Inc. a misé sur le solutionnement de ces problèmes à un stade relativement précoce, en commençant par l‘utilisation du monomère MDP original développé en 1981.

Optimiser la perfomance d'adhésion

Le monomère MDP original répondait au problème de durabilité limitée de la performance d‘adhésion des systèmes adhésifs. Le groupe hydrophile (phosphate) du MDP forme une liaison chimique particulièrement solide et durable avec le calcium de l‘hydroxyapatite, le principal composant de l‘émail et de la dentine. Le sel MDP-Ca formé procure la base pour une couche hybride stable, solide et durable. En combinaison avec la résine de l‘agent adhésif, le résultat est un scellement hermétique de la cavité après photopolymérisation. Jusqu‘à l‘heure actuelle, le MDP est un composant essentiel de tout produit adhésif de Kuraray Noritake Dental Inc., et c‘est le composant clé qui a fait de CLEARFIL™ SE Bond le système adhésif à auto-mordançage de référence absolue.

Cependant, convaincue que les adhésifs dentaires devaient apporter davantage qu‘une seule adhésion solide et durable, Kuraray Noritake Dental Inc. a commencé à se pencher sur un autre problème : le risque de déminéralisation et de cavitation causé par les bactéries restées dans la cavité. Sur la base de son expérience dans le développement d‘autres monomères adhésifs, Kuraray Noritake Dental Inc. a inventé le monomère MDPB qui a pour une action de nettoyage antibactérien de cavité. Différent d‘autres agents antibactériens qui pourraient nuire à la solidité de l‘adhésion d‘un adhésif appliqué ultérieurement, le monomère MDPB détruit les bactéries persistantes sans affecter la performance d‘adhésion. Il est contenu dans l‘apprêt de l‘adhésif à auto-mordançage en deux flacons CLEARFIL™ SE Protect et est immobilisé par polymérisation.

Le mécanisme bactéricide du MDPB est supposé similaire à celui de l‘agent antibactérien bien connu qu‘est le CCP (chlorure de cétylpyridinium), qui est contenu dans de nombreux dentifrices et bains de bouche.

Si l‘adhésif à auto-mordançage en deux flacons a simplifié la procédure d‘adhésion, la version en flacon unique a permis d‘aller encore plus loin. Réunir les ingrédients des systèmes en étapes multiples dans un seul flacon sans compromettre la stabilité du produit relève du défi. La technologie actuelle permet désormais cela. Pour sceller la surface le plus tôt possible après l‘application, la pénétration des monomères dans le tissu dentaire doit être rapide et efficace. En général, la pénétration est toutefois ralentie par les monomères qui ont besoin de temps pour pénétrer la structure dentaire - en particulièrement la dentine humide - et requièrent parfois même un mouvement de friction à cette fin. C‘est pourquoi Kuraray Noritake Dental Inc. s‘est concentrée sur le développement de la Rapid Bond Technology. Elle consiste dans le monomère MDP original associé aux monomères hydrophiles à réticulation d‘amide nouvellement développés et intégré à CLEARFIL™ Universal Bond Quick. Les monomères amides hydrophiles permettent une pénétration rapide, complète et profonde dans la dentine et forment avec la polymérisation un dense réseau polymère réticulé responsable d‘une adhésion solide et durable. Ainsi, les temps de friction et d‘attente sont supprimés et un scellement hermétique et durable de la cavité est réalisé après photopolymérisation.

En raison de leur hydrophilie (affinité avec l‘eau), les monomères amide de la Rapide Bond Technology pénètrent très bien la dentine. Après photopolymérisation, l‘adhésion présente une faible absorption d‘eau et donc une grande résistance dans le temps.

Optimiliser les restaurations directs

Combiner plusieurs couches, nuances et opacités : Heureusement, l‘utilisation de techniques de stratification très complexes pour créer des restaurations composite naturelles appartient au passé dans de nombreuses situations cliniques. En effet, les résines composites hautement développées se mélangent parfaitement à la structure dentaire adjacente. Pour fournir cette caractéristique favorable, Kuraray Noritake Dental Inc. a développé sa propre technologie de diffusion de la lumière (« Light Diffusion Technology », LDT). Cette technologie est incorporée dans des charges spécialement pré-polymérisées qui agissent comme des millions de micro-prismes transmettant et réfractant la lumière et la couleur depuis la structure dentaire alentour. Optimisés en taille, distribution et indice de réfraction par rapport à la matrice, les charges offrent un mélange naturel incomparable. L‘ensemble de la gamme de composites CLEARFIL MAJESTY™ contient cette technologie de charge maison. CLEARFIL MAJESTY™ ES-2 Universal, le dernier produit dans lequel Kuraray Noritake Dental Inc. fait usage du niveau supérieur de LDT permet une technique à nuance unique avec simplification de la sélection de nuance : il est disponible en deux nuances pour la zone antérieure et en une nuance unique pour la zone postérieure, mais se mélange si bien qu‘une couverture de quasiment chaque nuance du nuancier VITA classique A1-D4 est obtenue.

La réfraction et la transmission de la lumière sont le moyen d‘obtenir une excellente intégration optique : les charges de diffusion de la lumière de CLEARFIL MAJESTY™ ES-2 de Kuraray Noritake Dental Inc.

Étant donné qu‘un excellent aspect ne dépend pas seulement de l‘intégration optique et de marges de restauration indétectables, Kuraray Noritake Dental Inc. a également développé des charges qui assurent le reste, à savoir une brillance de surface naturelle et une rétention de polissage durable. La solution intégrée dans CLEARFIL MAJESTY™ ES Flow avec ses trois niveaux de fluidité est appelée « Submicron Filler Technology », consistant en des charges brillantes de taille submicronique. Ces charges sont si petites que les réflexions lumineuses offrent un effet naturel, même après usure. L‘exceptionnelle technologie silane de Kuraray Noritake Dental Inc. est utilisée pour rassembler des millions de ces charges submicroniques et les maintenir ensemble dans la durée. Elle permet des charges élevées dans les composites de faible viscosité et limite l‘absorption d‘eau qui entraînerait autrement une dégradation du composite polymérisé. L‘équilibre parfait entre les charges submicroniques brillantes, les charges de diffusion de la lumière, la matrice de résine et la propre technologie silane offre une combinaison équilibrée de propriétés mécaniqueset optiques.

Exemple d‘une restauration « single-shade » avec CLEARFIL MAJESTY™ ES-2 Universal.

Conclusion

Monomères adhésifs, technologies de charge et technologie silane procurent une solide combinaison de charges, clusters et matrice résine : Clairement, Kuraray Noritake Dental Inc. est un expert de confiance dans le domaine des restaurations adhésives. Ses propres technologies développées au cours des dernières décennies ont incontestablement contribué à améliorer (à long terme) la performance des restaurations directes et à faciliter l‘obtention de résultats fiables et esthétiques.

Interview with Andreas Chatzimpatzakis

Fewer bakes, fewer ceramic powders - there is clearly a trend toward simplification in the production of zirconia-based prosthetic work. This is also true for implant-based restorations, which often involve gum parts. DT Andreas Chatzimpatzakis, international trainer for Kuraray Noritake Dental Inc., and the owner of ACH Dental Laboratory in Athens, Greece, shares his approach to high aesthetics in implant prosthodontics in the following conversation.

You are a user of the CERABIEN™ ZR portfolio from the outset. When did you test the products for the first time and why?

Well, it was many years ago when I finished my very first zirconia-based restoration. The reason to test CERABIEN™ ZR was that when I asked the dental technician who had milled the framework which porcelain system to use. He suggested to use CERABIEN™ ZR, which I did. I was immediately impressed by the system and by the outcome I was able to achieve on the first attempt.

Did you ever test any other porcelain systems for ceramic layering?

Yes. Before I becoming an international trainer for Kuraray Noritake Dental Inc., I had the opportunity to test many other porcelain systems for layering on zirconia. Based on this experience, I can say that CERABIEN™ ZR is unique and the best system I have ever used. The reason is that its translucency and chroma are extremely close to natural teeth. In addition, due to a controlled firing shrinkage, a One-Bake Technique may be employed even in long-span restorations.

Your hands-on demonstration at the Kuraray Noritake Dental booth during the IDS 2023 in Cologne focused on White and Pink Aesthetics achieved with CERABIEN™ ZR. Is there a specific concept you use?

Nowadays, everyone producing dental restorations – no matter whether based on natural teeth or on implants – is confronted with increasing aesthetic demands of patients and dental practitioners. The high demands are developed because life-like restorations and cosmetic dental treatment outcomes are presented everywhere in the web and on social media. The showcased quality of outcomes is simply expected, even if the financial budget is limited. To be able to fulfil these demands in the field of implant-based prosthodontics, I have developed an approach that allows me to achieve high aesthetics with little effort. My concept is based on using not too many ceramic powders. For extra chroma and special characterization, I rely on the power of the internal live stain technique, first introduced by Hitoshi Aoshima-sensei.

Please summarize the most important details of your presentation.

The first important detail is the design and characterization of the framework. Before sintering, I apply Esthetic Colorant for KATANA™ Zirconia. After the sintering process, shade base stain and internal stains are mixed and applied. In this way, I create a nice canvas that helps me to achieve a life-like result with only a few selected ceramic powders. In most cases, three to five powders are enough to produce a great result. Among the powders used most frequently are Opacious Body, Body, LTX, Mamelon and CCV. After the first bake and a little grinding, I make use of internal stains again. They offer support in the controlling of the chroma and the integration of special characteristics. When this step is completed, the final build-up is done with one or two ceramic powders, most of the times LT1 and Enamel or LT0. Pink aesthetics are usually created with Tissue 1, 3 and 5. For the free gingiva, LT Coral is my go-to solution. The major goal is always to obtain maximum quality in a minimum of time. To achieve this, a good knowledge of the materials and of course practicing – on both, porcelain build-up and morphology – are strictly required.

Fig. 1. Complex implant-based restoration: Framework design.

Fig. 2. Esthetic Colorant …

Fig. 3.  … applied prior to the final sintering procedure.

Fig. 4. Appearance after sintering.

Fig. 5. Final outcome.

Are there any concrete tips and tricks you would like to share?

For the characterization of the framework, I mix the internal stains with shade base stain powders; mostly with SS Fluoro. For the first bake, especially when the restoration is large and the amount of ceramic to be applied huge, I reduce the heating rate up to 38 degrees per minute. I also increase the drying process up to 17 or even 20 minutes depending to the restoration. Experience shows that these measures optimize the aesthetic outcomes.

You often mention that it is extraordinarily important to understand the morphology of natural teeth to be able to produce beautiful restorations. Why is this the case?

A successful prosthetic restoration needs to offer proper function and aesthetics. Function means a precise fit, perfect contact points and occlusion, a proper emergence profile and interproximal embrasures for self-cleaning etc. All this is described by the term morphology. Aesthetics, on the other hand, is guided by shape and colour. The effort required to establish a proper morphology is much higher (about 70 percent of the total work) than the effort involved in obtaining the right translucency, opalescence and chroma.

What instruments do you use to imitate the morphology of natural teeth and how do you do it?

I usually make use of the Optimum™ Spring Ceramic Brush Size 8 (MPF Brush Co.), stones and diamond burs for detailed grinding and carving after the final bake. I studied morphology at the Osaka Ceramic Training Centre in Japan with Shigeo Kataoka-sensei. According to him, a key factor in creating a perfect macro and micro morphology lies in the shadows. To be able to take into account the interference of light and shadow during grinding, a light source is placed on one side of the restoration.

How many bakes do you need to produce highly aesthetic restorations?

It depends on the case, although in many situations, I nowadays opt for some kind of micro-layering. Lately, I have used micro-layering a lot with internal stain directly on the zirconia framework. In other cases, I do a quick first bake, then the internal staining, a final bake and glazing. For small or single-unit restorations in the posterior region, a One-Bake Technique is often sufficient. Even a Zero-Bake approach using Esthetic Colorant on a monolithic zirconia restoration may be appropriate here, and it is very convenient. If there is a restoration with high aesthetic demands – these are typically single anterior restorations – the technique I select depends on the shade. In some cases, using only the internal stain technique is enough to reach a high aesthetic level, while in other cases, additional steps need to be taken. To my mind, there is no single technique that fits all cases. As mentioned before, I try to achieve high aesthetics in a minimum of time.

Fig. 6. Clinical example of achieving high aesthetics in a minimum of time: Before …

Fig. 7. … and after crown placement.

Fig. 8. High aesthetics …

Fig. 9. … achieved in a minimum of time.

Did your approach change due to the availability of high-translucency zirconia materials with colour (and flexural strength) gradation?

Well, yes! My overall approach changed more to micro-layering. Several years ago, we needed to consider how to mask the framework and how to achieve translucency in areas with limited space. The problem was solved for single-unit and small anterior bridge restorations with the availability of KATANA™ Zirconia UTML and STML. With the introduction of KATANA™ Zirconia YML, a high-translucency material became available for long-span or implant-based restorations as well. We have strength and translucency all in one disc. In most of my cases, the framework material replaces the dentin with regard to morphology and shade. Hence, I need to focus on adding the enamel by applying the transparent and translucent powders. The powders of the internal stain technique are used to characterize the framework, and with a micro-layer of porcelain, the goal of creating an aesthetic restoration in the minimum of time is achieved. This is exactly why I am sure that micro-layering is the future.

What drives you to share your knowledge with others?

My passion! I love my work! And I love to see technicians become better and better. Dental technology is an exciting journey, a journey that begins when the first impression arrives in the dental laboratory, and it ends when the final restoration is cemented into the patient’s mouth. And this journey is so exciting because we change lives. We change people’s personalities, we give them back their smile, we give them back their self-respect. Consider that every day, every single moment working on our bench trying to imitate nature… there is nothing more exciting than that!!!

My approach as an instructor is to lead dental technicians to master the art of observing natural teeth. This is the way every individual will understand morphology and shade. You need no special talent to be a very good dental technician. You need to observe! Your eyes see, your mind understands, and your hands will follow.