When art meets technology;
Logical evolution of design and techniques: Microlayering with Kuraray Noritake new porcelains. 

DANIEL RONDONI
Born in Savona in 1961, he lives and works in his hometown where he has been the manager and director of his own laboratory since 1982.

Tvirtas ir patvarus dantų ir protezų sukibimas yra lemiamas veiksnys, turintis įtakos ilgalaikiam dantų protezų efektyvumui. Tačiau sukibimo kokybei turi įtakos ne tik rišamoji medžiaga ar cementavimo tirpalas, bet ir rišamosios medžiagos paviršiaus būklė. Tiems, kurie nori paprastai užtikrinti švarius dantis ir protezų paviršių, „Kuraray Noritake Dental“ sukūrė „KATANA™ Cleaner“ – universalią valymo priemonę su MDP druska ir 4,5 pH vidiniam ir išoriniam naudojimui burnoje.

Įrodyta, kad seilių ir kraujo baltymai turi neigiamą poveikį dantų klijų efektyvumui. Ypač atliekant netiesiogines procedūras, tačiau neįmanoma rišamosios medžiagos paviršiaus apsaugoti nuo skysčių. Pritaikymo metu paruošti dantys ir protezai yra užteršiami ir juos reikia nuvalyti. Skalavimas vandeniu neturi pageidaujamo poveikio ir net naudojant daugelį įsigijamų valymo priemonių tam tikras baltymų kiekis dažniausiai lieka ant paviršiaus. Bandymai parodė, kad naudojant KATANA™ Cleaner arba šlifavimą smėlio srove pasiekiamas pageidaujamas švaraus valymo poveikis nepažeidžiant sukibimo stiprumo. Tai taikoma KATANA™ Zirconia protezams, o KATANA™ Cleaner taip pat užtikrina dentino ir emalio – burnos ertmės paviršių, kuriems negalima taikyti šlifavimo smėlio srove ir daugelio kitų valymo priemonių – pageidaujamus rezultatus.

KATANA™ Cleaner naudojimas turi ir kitų privalumų: valymo procedūra yra labai paprasta, greita ir švari. Universali valymo priemonė tiekiama buteliukuose su naujovišku atlenkiamu dangteliu, todėl į indą galima dozuoti viena ranka. Tada jis įtrinamas į protezo ir paruoštos danties struktūros paviršius arba atraminį dantį dešimčiai sekundžių, kurioms praėjus nuskalaujamas vandeniu ir išdžiovinamas. Dėl MDP druskos didelio paviršiaus aktyvumo, šių dešimties sekundžių pakanka iš substrato pašalinti beveik visus baltymus, todėl sukuriamos sąlygos, labai panašios į neužteršto rišamosios medžiagos paviršiaus sąlygas. Galiausiai, taikoma rišamoji medžiaga arba cementavimo tirpalas, t. y. PANAVIA™ V5 arba PANAVIA™ SA Cement Universal pagal gamintojo naudojimo instrukcijas.

Rezultatas – ilgalaikis sukibimas, kuris suteikia naudotojams ramybę. Eksperimente dalyvavę naudotojai, kurie jau išbandė gaminį, sutinka, kad naudojant KATANA™ Cleaner lengvai optimizuojama sukibimo kokybė ir klijavimo procedūros eiga.

Žiniasklaidos ir klientų užklausos
Kuraray Europe Benelux, Nordics & Baltics
infobaltics@kuraray.com l kuraraynoritake.eu/lt/katana-cleaner

Kuraray Noritake Dental Inc. įkurta 2012 m. balandžio mėn. sujungus Kuraray Medical Inc. ir Noritake Dental Supply Co. Sujungusi šių dviejų tarptautinių įmonių stiprybes, Kuraray Noritake Dental siekia sukurti pasaulyje pirmaujančią sinergiją tarp produktų kūrimo, gamybos ir pardavimo.

Įmonė turi neįkainojamos patirties neorganinės chemijos srityje, todėl ir toliau gali kurti aukštos kokybės stomatologinius produktus – nuo keramikos ir kompozitų iki biologinių medžiagų.

Kuraray Noritake Dental tiki, kad paciento šypsena yra svarbiausia. Todėl įmonė visada siekė įkvėpti odontologus tiek dabar, tiek ateityje pristatydama mažai invazinius ir biologinių priedų turinčius tirpalus, kuriuos naudojant pacientas visą likusį gyvenimą gali džiaugtis savo dantimis.

Our commitment to you:

Kuraray Noritake dental products offer dental professionals all over the world high-quality products using simple procedures with long-lasting results. With the COVID-19 outbreak, all of us are now going through difficult times which we were not prepared for. Our thoughts are with all those people who are affected by the coronavirus pandemic.

We, at Kuraray Europe GmbH, as the European sales office of Kuraray Noritake Dental Inc., feel a strong responsibility towards our customers and partners, colleagues and communities and we would like to inform you that, in spite of the challenges we are now facing, we will do our best to provide you with the services that you require:

1. Business as usual.

It is both important that we continue to provide products and services to all our customers and at the same time secure the safety of our employees. With that in mind, we have transitioned most of our employees not involved in manufacturing to working remotely and eliminated all non-essential and cross-border travel. This change should not impact in any way how you, our dear customers, contact us. We are ready, willing and able to support you. Clearly, to keep face-to-face interactions to a minimum, we will focus our communication on what is most convenient for you – either a phone call, through email or video chat (Skype, FaceTime or Google Hangout). Whatever is convenient for you!

2. Delivery

As of today, we have sufficient inventory for both dentists and dental labs, as well as reliable logistics. Thanks to our global network of dealer-depots, dental professionals all over the world will continue to have direct local access to our wide range of Kuraray Noritake Dental products. Kuraray Europe GmbH will exert every effort possible to deliver your orders on time. Parallel to this, we kindly ask you to make sure that somebody in your office will be available to receive the parcel. In case, for whatever reason this is not possible, please notify your supplier in advance.

3. Technical Services.
   Our technical service is available to meet your needs.

If there is anything else that we can do to support you, please let us know.

We wish you all the best. Take good care and stay healthy.

Sincerely,

Kuraray Europe GmbH

BU Medical

„Dental Advisor“ išrinktas kaip pagrindinio prizo laimėtojas penkis metus iš eilės, „CLEARFIL MAJESTY^TM ES Flow“ dabar galimas su trimis srautais, todėl yra dar universalesnis ir suteikia galimybę stomatologams greičiau ir lengviau pasiekti pageidaujamą atkūrimo rezultatą.

„CLEARFIL MAJESTY^TM ES Flow“ universalus srautinis kompozitas yra pagrindinė „Kuraray Noritake Dental“, pasaulyje pripažintos įmonės dėl atkuriamųjų medžiagų, naujovė. „Kuraray Noritake Dental“ sėkmę pasiekė sukurdama labai pažangų produktą „CLEARFIL MAJESTY^TM Flow“, kuris atkuria, taiso ir cementuoja, todėl nereikia naudoti kitų kompozitų.

Dėl „Kuraray Noritake Dental“ patentuotos silano jungiamosios medžiagos, naudojamos „CLEARFIL MAJESTY^TM ES FLOW“, tiek submikroniniai, tiek nanoklasteriniai užpildai stabiliai sujungiami į kompozitą. Todėl „CLEARFIL MAJESTY^TM ES FLOW“ pasižymi labai geromis užpildo ir srautinėmis savybėmis. Estetinį vaizdą pabrėžia nanoklasteris arba lengvi difuziniai užpildai, kurie leidžia kompozitui sklandžiai susilieti su aplinkine danties struktūra.

„CLEARFIL MAJESTY^TM ES FLOW“ privalumai

• Efektyvus ir lengvas tvarkymas: švirkščiamas tiesiai iš švirkšto, paprastai ir lengvai poliruojamas.
• Stiprus: kompozito lenkimo stipris – 150 MPa, o atsparumas gniuždymui – 373 MPa.
• Platus pritaikymas: visos ėduonies klasės, cementavimas ir taisymas.
• Estetika: puikus spalvos pritaikymas dėl lengvos difuzinės technologijos.

Vienintelis kompozitas, kurio pakaks stomatologui.

Daugiau informacijos rasite: kuraraynoritake.eu/lt/clearfil-majesty-es-flow
Kuraray Europe Benelux B.V., Nordics & Baltics l infobaltics@kuraray.com

„Kuraray Noritake Dental Inc“ įkurta 2012 m. balandžio mėn. sujungus „Kuraray Noritake Dental Inc“ ir „Noritake Dental Supply Co“. Įmonė turi neįkainojamos patirties neorganinės chemijos srityje, todėl ir toliau gali kurti aukštos kokybės stomatologinius produktus – nuo keramikos ir kompozitų iki biologinių medžiagų.

Praėjus vos vieniems metams po to, kai rinkai buvo pristatytas naujoviškas produktas „KATANA™ Zirconia Block“, įmonė „Kuraray Noritake Dental“, plačiai žinoma dėl savo naujovių ir patirties restauracinių odontologinių medžiagų srityje, didžiuodamasi pristato „KATANA™ Zirconia Block for Bridge“.

„KATANA™ Zirconia Block“ pasižymi įvairiais privalumais – odontologas gauna naujovišką daugiasluoksnį cirkonio bloką, kuris tuo pat metu atrodo natūraliai ir yra patvarus. Naudojant produktą kartu su „Dentsply Sirona“ sistema CEREC, sukepinimo procesas yra greitesnis nei bet kada anksčiau – tik 18 minučių, todėl visą atkuriamąjį protezą iš cirkonio (įskaitant projektavimą, frezavimą ir sukepinimą) galima paruošti maždaug per 35 minutes odontologo kabinete.

Pasiūlius rinkai „KATANA™ Zirconia Block for Bridge“, odontologai gavo dar universalesnį produktą, turintį visus „KATANA™ Zirconia Block“ privalumus. Naudojant šį produktą galima pagaminti atkuriamuosius protezus, pasižyminčius puikiu lenkimo stipriu. Be to, jie tolygūs ir permatomi, taigi labai panašūs į natūralius dantis.

Ryšiams su žiniasklaida ir klientų užklausoms:
Kuraray Europe Benelux, Nordics & Baltics
infobaltics@kuraray.com l kuraraynoritake.eu/lt/katana-zirconia-block

Įmonė „Kuraray Noritake Dental Inc,“ buvo įkurta 2012 m. balandžio mėn. sujungus „Kuraray Medical Inc“ ir „Noritake Dental Supply Co“. Naudodamasi šių dviejų tarptautinių įmonių pajėgumais „Kuraray Noritake Dental“ siekia sukurti pirmaujančią pasaulyje odontologinių produktų kūrimo, gamybos ir pardavimo sinergiją.

Išskirtinė patirtis organinės ir neorganinės chemijos srityse – tai privalumas, kuris padeda įmonei kurti ir tobulinti pažangius odontologijos produktus – nuo keramikos iki kompozitų ir netgi biologinių medžiagų.

„Kuraray Noritake Dental“ mano, kad visų svarbiausia – paciento šypsena. Todėl įmonė siekė ir ateityje sieks įkvėpti odontologijos specialistus, siūlydama minimaliai invazinius sprendimus ir biologinius priedus, kad pacientai galėtų džiaugtis savo dantimis visą gyvenimą.

„KATANA™ AVENCIA™ Block“ – naujausias revoliucinis „Kuraray Noritake Dental“ gaminys. „Kuraray Noritake Dental“ plačiai žinoma dėl savo naujovių ir patirties, įgytos ilgus metus dirbant su atkuriamosiomis odontologinėmis medžiagomis ir jas tobulinant.

Sukurtas naudojant unikalų ir naujovišką gamybos metodą, „KATANA™ AVENCIA™ Block“ leidžia odontologijos specialistams pasiekti ilgalaikį nepriekaištingą blizgesį. Be to, šis produktas atsparus dilimui ir jo nereikia sukepinti. Taigi dabar odontologai visapusiškai puikų rezultatą gali pasiūlyti greičiau ir įdėdami mažiau pastangų nei iki šiol.

Naujojo produkto „KATANA™ AVENCIA™ Block“ išskirtinumą lemia nanodalelių dydžio užpildai, kurie suspaudžiami į tankų bloką. Po to blokas tolygiai impregnuojamas dervos monomeru ir polimerizuojamas šiluma. Rezultatas – visiškai naujos rūšies hibridinė keramika, pakankamai stipri, kad išlaikytų okliuzinį spaudimą, ir ilgiau išlaikanti nepriekaištingą blizgesį.

Ryšiams su žiniasklaida ir klientų užklausoms:
Kuraray Europe Benelux, Nordics & Baltics
infobaltics@kuraray.com l kuraraynoritake.eu/lt/katana-avencia-block

Įmonė „Kuraray Noritake Dental Inc,“ buvo įkurta 2012 m. balandžio mėn. sujungus „Kuraray Medical Inc“ ir „Noritake Dental Supply Co“. Naudodamasi šių dviejų tarptautinių įmonių pajėgumais „Kuraray Noritake Dental“ siekia sukurti pirmaujančią pasaulyje odontologinių produktų kūrimo, gamybos ir pardavimo sinergiją.

Išskirtinė patirtis organinės ir neorganinės chemijos srityse – tai privalumas, kuris padeda įmonei kurti ir tobulinti pažangius odontologijos produktus – nuo keramikos iki kompozitų ir netgi biologinių medžiagų.

„Kuraray Noritake Dental“ laikosi nuomonės, kad visų svarbiausia – paciento šypsena. Todėl įmonė siekė ir ateityje sieks įkvėpti odontologijos specialistus, siūlydama minimaliai invazinius sprendimus ir biologinius priedus, kad pacientai galėtų džiaugtis dantimis visą gyvenimą.

Pradėjusi nuo naujovių klijavimo ir silano technologijos srityse „Kuraray Noritake Dental“ dabar siūlo visiškai naują cementavimo lipnia derva metodą. „PANAVIA™ SA Cement Universal“.

„PANAVIA™ SA Cement Universal“ su unikalia silano adhezine medžiaga – LCSi monomeru užtikrina tvirtą, patikimą cheminį sukibimą praktiškai su bet kokiomis odontologijoje naudojamomis medžiagomis: porcelianu, ličio disilikatu, kompozitine derva ir net stiklo keramika, nenaudojant atskiro grunto. Be po, didelė pradinė MDP monomero koncentracija leidžia pagerinti cheminį reaktyvumą su cirkoniu, dentinu ir emaliu.

„PANAVIA™ SA Cement Universal“ parduodamas su „Automix“ švirkštais, tad jį galima lengvai tepti be dalytuvo. Šis produktas tinka dantų vainikėliams, tiltams, įklotams, užklotams, kaiščiams ir netgi klijuojamiems tiltams, nes unikalus kietėjimo technologijų derinys užtikrina greitą kietėjimą ir patikimą sukibimą. Todėl dabar cementavimas tapo universalesnis ir paprastesnis nei bet kada anksčiau, o jo rezultatai – tvirtesni.

Ryšiams su žiniasklaida ir klientų užklausoms:
Kuraray Europe Benelux, Nordics & Baltics
infobaltics@kuraray.com l kuraraynoritake.eu/lt/panavia-sa-cement-universal

„PANAVIA™ SA Cement Universal“ – naujovė, kurią siūlo įmonė „Kuraray Noritake Dental Inc,“ įkurta 2012 m. balandžio mėn. sujungus „Kuraray Medical Inc“ ir „Noritake Dental Supply Co“. Naudodamasi šių dviejų tarptautinių įmonių pajėgumais „Kuraray Noritake Dental“ siekia sukurti pirmaujančią pasaulyje odontologinių produktų kūrimo, gamybos ir pardavimo sinergiją.

Išskirtinė patirtis organinės ir neorganinės chemijos srityse – tai privalumas, kuris padeda įmonei kurti ir tobulinti pažangius odontologijos produktus – nuo keramikos iki kompozitų ir netgi biologinių medžiagų.

„Kuraray Noritake Dental“ laikosi nuomonės, kad visų svarbiausia – paciento šypsena. Todėl įmonė siekė ir ateityje sieks įkvėpti odontologijos specialistus, siūlydama minimaliai invazinius sprendimus ir biologinius priedus, kad pacientai galėtų džiaugtis dantimis visą gyvenimą.

Kuraray celebrates its 90th anniversary in 2016. We take the opportunity of this occasion to offer you a glimpse of the history of Kuraray from a new perspective. The name Kuraray represents more than 8,300 employees and an annual turnover of approximately 3.7 billion euros. Kuraray was founded in Kurashiki, Japan, in June 1926, by Magosaburo Ohara. Kuraray began with the domestic production of Rayon, a synthetically produced cellulose fibre referred to as artificial silk, a new and innovative product at the time. 

The name KURARAY is derived from the location: Kurashiki and the product manufactured: Rayon. The development of this branch of production developed very quickly in Japan, with many other major manufacturers establishing themselves during this period. Whereas others recruited their technicians and experts from elsewhere, Kuraray established the Kyoko Research Laboratory, which was managed by the University of Kyoto to generate expertise and support for the development of the required technologies. Ohara also committed himself to cultural and social projects. The building of an art gallery and the financing of an orphanage represent only two of his many projects in Kurashiki. The Ohara Museum of Art was the first private museum of Western art in Japan.

Ohara considered the dreadful conditions in which employees commonly worked and lived at the time to be unacceptable; he was not a profit-driven employer, and attempted to solve such issues. He ensured that decent accommodation, fitness facilities and nursery schools were built to provide young employees, or families who had left their homes to work for Kuraray, with everything they needed for education and a healthy and culturally rich lifestyle.
One of the largest general hospitals in the west of Japan, the Kurashiki Central Hospital, was originally founded by Kuraray to promote the well-being of employees and their families. It is still considered to be one of the most famous hospitals in Japan.

With the production of Kuralon in 1950, developed from the in-house manufactured products PVA and vinyl acetate, Kuraray expanded to become the specialist chemical company it is today. Always intent on making a contribution to the good of society, Kuraray addressed the subject of environmental protection very early on. The visionary Ohara was aware of the seriousness of environmental pollution, and made great efforts to prevent it.

Internationally too, Kuraray has remained aware of its social responsibilities. After the war, a production facility was opened in China which helped to improve the poor post-war living conditions of the Chinese population.
Today, Kuraray is a leading global manufacturer of the specialist chemicals used in many aspects of daily life. Kuraray has always viewed its employees as its most important asset, and continues to do so to this day.

In 1978, Kuraray shook up the dental market with the introduction of CLEARFIL BOND SYSTEM F, the world’s first total-etch adhesive system. Having inaugurated the era of adhesive dentistry, we steadily introduced new dental products over the following years. In 1983, Kuraray introduced the PANAVIA EX resin cement. By utilising our patented MDP monomer technology developed in-house, PANAVIA EX enabled Kuraray to set the industry standard for adhesion—a position we have held in the decades since. This year marks the 40th anniversary of Kuraray’s entry into the commercial dental products market, providing a perfect opportunity to reflect on how far we have come since.

Kuraray—Rooted from a true trailblazer 
Founded in June 1926 by Magosaburo Ohara in Kurashiki in Japan, Kuraray has transcended our humble origins as a producer of rayon to become a leading global manufacturer of medical products, materials, textiles, chemicals, resins and much more. Our commitment to research and development in the fields of chemistry and engineering has led to many market firsts and a reputation as a pioneer of new products and technologies. 

A history of innovation
From the very beginning, Kuraray has been focused on the manufacture of high value-added products. At the time of the business’s birth, rayon was a new type of synthetic material, and over the ensuing years, Kuraray was able to master its production. In 1950, we became the first company in the world to develop the technology to mass-produce POVAL (polyvinyl alcohol), paving the way for the production of the new synthetic fibre Vinylon in the same year. CLARINO, a water-resistant synthetic leather substitute for shoes, bags and other items, was released in 1964 after extensive research and testing, and quickly collected international awards for its technology.

Kuraray’s continued emphasis on independently developed proprietary technologies and techniques, rather than relying on imported alternatives, has enabled our company to provide original, high-quality products for a variety of different industries. High on this list is dentistry.

The Kuraray Noritake Dental era
In April 2012, Kuraray Medical and Noritake Dental Supply merged to form Kuraray Noritake Dental. By bringing together the materials and technologies developed by each of these market-leading companies, Kuraray Noritake Dental has continued to deliver dental bonding agents, ceramics and other reliable products to over 90 countries worldwide. The KATANA Zirconia range, for example, employs our unique multi-layered zirconia technology to provide a ceramic restorative material with superior translucency and perfect blending properties, while rapid bond technology ensures that CLEARFIL Universal Bond Quick delivers a lasting bond faster and easier than ever. 

Through a focus on research and production, Kuraray Noritake Dental is ideally positioned to continue providing leading-edge solutions to dental issues both now and in the future. 
 

Reliable adhesive cementation of zirconia

10-Methacryloyloxydecyl Dihydrogen Phosphate is a bit of a tongue-twister for anyone who is not a chemist by profession, so in everyday communication, this adhesive monomer is referred to by the three initial letters: MDP. MDP is indispensable in the dentistry business. For example, reliable adhesive cementation of zirconia restorations would not be possible without MDP. This adhesive monomer was developed by Kuraray Noritake Dental in 1981.

Requirements
Indirect restorations in modern dentistry must fulfil at least three requirements. First of all, they must be tissue-saving. This implies that a full crown is not the first choice, because approximately 70% of the tooth tissue has to be sacrificed for such a restoration. Nevertheless, full crowns are often still indicated by virtue of their mechanical retention. But given that the retention which can be achieved by adhesive cementation is now sufficiently reliable, a less invasive restoration than a crown should be chosen more often. And this choice may very well be for a zirconia restoration. Combined with the preliminary sandblasting of such an adhesive restoration, this choice is now an appropriate one thanks to MDP.

Durability is the second requirement for an indirect restoration. This quality of a restoration is largely associated with the flexural strength of the restoration material. While it has become clear that zirconia achieves the best durability scores, it should be pointed out that the cementation method also contributes significantly to the durability of a facing, inlay, onlay, etching bridge etc., which can nowadays all be realised in zirconia.

KATANA Zirconia UTML

KATANA Zirconia STML

KATANA Zirconia ML

AESTHETICS
Aesthetic acceptability is the third requirement for a modern indirect restoration. This means that porcelain baked on metal has become a thing of the past; full-ceramic materials are now the standard. Zirconia still has a relatively poor reputation in terms of aesthetics due to the extreme whiteness of the earliest examples from the turn of the century. Types of zirconia are now available with varying translucencies, and there are even so-called multi-layer varieties (KATANA Zirconia ML, STML and UTML by Kuraray Noritake), and these new zirconia no longer have to be porcelain-baked. Obviously, baking is still possible, and partial baking is a choice that is frequently made. One of the results of a multi-layer build-up is that the transparency is higher incisally than cervically, as it is in natural elements; the light falls through the incisal margin, but is blocked at the cingulum of the restoration. With a modern zirconia material such as KATANA Zirconia ML, this variable transparency goes hand in hand with a natural colour gradient from cervical to incisal. In a given colour, A1 for example, the cingulum has the corresponding dentine shade body and it passes to incisal in the appropriate enamel colour via two transition shades.

These veneers were made from KATANA Zirconia UTML and coloured using CERABIEN ZR External Stain

SURFACE
The new zirconia materials are changing the way dental technicians operate, as illustrated by the experience of Daniele Rondoni, a renowned dental technician. This professional, from Savona in Italy, has specialised in the use of Multi-Layering technology for ceramic materials (Tecnica della Multistratificazione in Ceramica). According to his philosophy, the choice of restoration materials should be so wide that customised solutions can be realised. Among other things, he believes that there will still be room for baked porcelain on a core of lithium disilicate or zirconia. Using baked porcelain, the dental technician can modify the surface texture of an aesthetic restoration to lend, as it were, a certain age to the restoration.

As for surface structure, the fact that the material allows for the smooth polishing of the occlusal plane is crucial to counteract abrasion by the antagonist and to maintain the occlusal balance. In this respect, the hardness of the material selected is not the main factor; the smoothness and resistance of the surface are far more important.

FLEXURAL STRENGTH
When selecting material for restorations, the dental technician also has the option to choose KATANA Zirconia Ultra Translucent Multi-Layered for veneers or anterior crowns; a zirconia with a translucence comparable to that of glass. This translucence is especially important with anterior restoration which is to be fitted between flawless natural elements, a situation that often occurs after anterior traumas. Such a restoration effected using KATANA Zirconia UTML harmonises with the neighbouring natural teeth, not least because this type of zirconia does not cause the frequently-occurring white appearance common in anterior crown. The modern aesthetic zirconia materials of the second generation are sintered at a temperature of 1,550°. This temperature is maintained for two hours. The dental technician needs to be aware that this temperature differs from the sintering temperature for KATANA Zirconia High Translucent Multi-Layered (1,500 °C). Wide-span bridges can be realised with the latter product, whereas the size of bridges made from KATANA Zirconia Super Translucent Multi-Layer remains limited to a maximum of four elements. KATANA Zirconia UTML can be used for small anterior bridges, but is more suitable for anterior crowns and veneers. The reason for this is that the flexural strength of these highly aesthetic zirconia materials is lower than the flexural strength of the standard zirconia, in which the flexural strength – 1,125 MPa – is sufficient for the production of durable widespan bridges. The flexural strength of the highly aesthetic zirconia varieties (approximately 750 MPa (STML) and 550 MPa (UTML)) is amply sufficient to ensure the durability of solitary aesthetic restorations and limited-span bridges.

Minimum wall thickness of KATANA*

* Maintain 0.8 mm thickness of pressed ceramic in all areas. When trimming of the zirconia framework the framework should be at least 0.4 mm.

PREPARATION
Flexural strength is not the only decisive factor for durability; the method of preparation is also crucial to properties of this material. Chamfer preparation is the required form of preparation,
with no knife-edge outline, no deep shoulder and, obviously, no undercuts. Since the restorations are fixed adhesively, parallel walls or grooves in the preparation are undesirable, and sharp
edges and transitions must be rounded off. If a preparation for a full crown has nevertheless been made, a substantial height difference between the vestibular and palatal/lingual outline is
contra-indicated.
 

Using the new zirconia materials means that a thickness of only 0.4 to 0.8mm need be removed for a veneer in the incisal and cervical area, and only 0.5mm is required in the labial plane,
which corresponds with the requirement to save tissue. For inlays, too, only 1mm is sufficient to achieve a durable result. If the inlay is extended to an onlay, 1mm is also sufficient for the
area where the cusps are capped. For a full crown in the lateral parts, a 1mm space must be kept as a minimum, which thickness must also be maintained for the upright walls of the preparation.

FIXATION
A wide range of possibilities have already been suggested for the durable fixation of zirconia-based restorations. All of these options have also been researched, but according to Prof. Matthias
Kern, there is no point in conducting further research into the best cementation procedure. This scientist and practitioner, who currently works at Kiel University, in Germany, has been involved
in the adhesive cementation of zirconia for nearly twenty years.Based on his wide experience, Kern is convinced that three requirements have to be met to achieve the reliable cementation
of zirconia. First of all, a rubber dam must be applied for the operation, which is obviously easier for partial restorations than for total restorations. It is not only from the perspective of tissuesaving that it is useful to keep the preparation limited for this reason. The second condition is that micro-mechanical adhesion needs to be achieved. For zirconia restorations, the necessary adhesion is obtained by sandblasting the surface. Obtaining chemical adhesion is the third condition. Based on extensive research, Kern is fully convinced that chemical adhesion can only be achieved by using MDP. His first publication on this subject dates back to 1998. It was the use of Kuraray Noritake’s PANAVIA, which did indeed contain MDP, which made it possible to achieve durable synthetic resin bonding to zirconia
after sandblasting.
 

SANDBLASTING
Dentists and dental technicians are apparently somewhat averse to sandblasting*, as evidenced by the extensive research conducted in an attempt to find an alternative. No such alternative has yet
been found. Efforts have been made to fuse a silica layer onto the zirconia to improve bonding, but according to Kern, the results of this procedure – the Rocatec method, for example – have been
disappointing. Nor is the silanisation of a zirconia restoration effective, because zirconia does not react to silan. Dentists who want to achieve the durable cementation of their zirconia restorations therefore have no other option than the purchase of a sandblasting device. Sandblasting can be carried out in a small cabin to prevent the surrounding area of the practice from being
affected. Soft air abrasion is carried out at 0.5 bar, while tight air abrasion is performed at 2.5 bar. The exact pressure is not all that crucial to the adhesion of the zirconia, providing that it is between
0.5 and 2.5 bar**. Kern advises sandblasting at a pressure of 1 bar, so that the surface to be bonded becomes somewhat rougher without this being visible to the naked eye. Obviously, the part of
the restoration that does not require bonding, such as the outside
of a veneer or the dummy of an etching bridge, has to be protected from the effect of the abrasive grains. It is also advisable to apply a colorant (waterproof marker pen) to the area to be sandblasted
prior to the operation. The colour disappears during sandblasting, making it easy to check that the entire adhesive surface has actually been abraded.

SANDBLASTING
Sandblasting of zirconia oxide at a lower pressure is a requirement for an effective adhesion. The
combination of sandblasting and MDP ensures both mechanical adhesion in the micro-roughness and
chemical adhesion between zirconia dioxide and MDP. There is extensive research material to corroborate the effectiveness of this method.

* It had long been assumed that the tetragonal and/or cubic structure would relapse into a
monoclinic state due to sandblasting, as a result of which fracturing would occur because
of the associated expansion. Sandblasting with aluminium oxide particles of 50 micron as a
maximum and a maximum air pressure of 2.5 bar does not, however, cause any damage.
** Airpressure is different from manufacturer‘s recommendation.

Adhesive monomer
The restoration surface can be cleaned using alcohol after the
sandblasting process. This step is optional. If the alcohol becomes
contaminated, for example, by saliva residues, the effect will be
negated, because the sandblasted surface would be contaminated
as well. The choice of the fixation procedure is relatively simple
provided MDP is used. This adhesive monomer was developed in
1981 by Kuraray Noritake Dental to improve the adhesive strength
to hydroxyapatite, and has proved its strength ever since. MDP is
not present in the glass ionomer cements (GIC’s), which, because
of their ease of use, are also sometimes used for the cementation
of zirconia restorations. ‘Don’t!’ warns Kern. It is clear from all the
studies that the composite cements containing MDP provide the
most durable results. The oldest known cement from this category
is PANAVIA EX, which was introduced in 1983. The optimised
PANAVIA V5 was presented recently as the single cement for
all cementation indications guaranteed to work according to a
predictable procedure. All the cements and bondings produced by
Kuraray Noritake contain MDP.

Possibly because Kern conducted his research in Maryland for
two years, he has recorded remarkable results with adhesively
cemented Maryland bridges (etching bridges). It has also become
apparent that, most of the time, an adhesion bridge functions best
with only one wing. For example, if a one-wing zirconia adhesion
bridge is cemented using a cement containing MDP instead of
a lateral upper incisive adhesive, such an adhesion bridge may
remain in place for up to 20 years, to the satisfaction of both
dentist and patient. This restoration, with its survival rate of 95.2%
after five years, therefore qualifies as a permanent restoration.

And the same goes for an onlay bridge made from zirconia.
Sandblasting and MDP; the formula for the durable bonding
of zirconia restorations.

So bear in mind: MDP also stands for a Mega Durable Product.

PANAVIA V5 for the adhesive fixation of zirconia
Achieving a reliable bonding to zirconia – it can be done! Read all about it in the preceding article.

PANAVIA V5 is the successful successor to both PANAVIA F2.0 and CLEARFIL ESTHETIC CEMENT. Thanks to its excellent adhesive bond with both dental tissue and all indirect materials, superior aesthetics, and unambiguous processing, PANAVIA V5 is a popular bonding cement. PANAVIA V5
provides a single cement for all cementation indications and features an unambiguous procedure.

CONCISE INSTRUCTIONS FOR USE
1. Sandblast the zirconia surface to be bonded with aluminium oxide powder (30-50 μm) at low pressure, then clean the restoration in an ultrasound bath and allow it to dry.

2. Apply CLEARFIL CERAMIC PRIMER PLUS to the restoration surface, then proceed to Apply & Go. Dry the entire surface using a gentle air flow.

3. Apply PANAVIA V5 Tooth Primer to the element and leave it to take effect for 20 seconds. Dry the surface with air.

4. Apply PANAVIA V5 Paste to the restoration surface and
position the restoration.

Applying the paste.

Positioning
After placement, remove excess cement using a gauze, a small brush, or something similar.

5. Remove surplus cement and light-cure. Always take account of the self-curing time needed for opaque elements and the use of PANAVIA V5 Opaque..

Daniele Rondoni

Owner of a dental laboratory in Savona

Professor Matthias Kern

Christian-Albrechts University