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!

AR KADA NORS SUSIMĄSTĖTE, KODĖL PREKĖS ŽENKLO „PANAVIA™“ GAMINIAI PASIŽYMI TOKIOMIS IŠSKIRTINĖMIS SAVYBĖMIS?

Tikriausiai žinote, kad visų jų sudėtyje yra originalaus MDP monomero, sukurto devintojo dešimtmečio pradžioje.  Jis sulaukė daug dėmesio, nes yra išties puikus adhezinis monomeras. Šis fosfatų esterio monomeras sudaro  labai tvirtą jungtį su danties struktūra, cirkonio oksidu ir odontologiniais metalais. Jis naudojamas visuose  PANAVIA™ gaminiuose. Vis dėlto kartu su MDP svarbūs ir kiti technologiniai veiksniai, padedantys užtikrinti mūsų  cementavimo sprendimų sėkmę, t. y. kitos katalizinės technologijos ir sudedamosios medžiagos.

SUDEDAMOSIOS DALYS, TURINČIOS ĮTAKOS POLIMERIZACIJOS REAKCIJAI

Viena iš šių lemiamų papildomų technologijų ir  sudedamųjų dalių yra polimerizacijos katalizatorius,  sukeliantis kietėjimo procesą. Polimerizacijos katalizatorius, kuris skiriasi nuo MDP monomero, naudojamo visuose PANAVIA™ gaminiuose, buvo nuolat tobulinamas nuo pat 1983  m., kai buvo pristatytas PANAVIA™  EX. Sukurtos naujos tokių produktų, kaip, pavyzdžiui, PANAVIA™ 21, „PANAVIA™ Fluoro Cement“ ir PANAVIA™ V5, versijos. Kitas svarbus elementas, taip pat turintis įtakos kietėjimo procesui, yra technologija „Touch Cure“, naudojama dviejuose iš trijų pagrindinių dabartinio PANAVIA™ asortimento gaminių – PANAVIA™ V5 ir „PANAVIA™ Veneer LC“. Pirmą kartą ši technologija panaudota 1993 m. pradėtame gaminti PANAVIA™ 21. Cheminio polimerizacijos aktyvatoriaus, esančio savaiminio ėsdinimo praimerio sudėtyje, kontaktas su dervos cemento pasta pagreitina cemento polimerizaciją nuo adhezinio vidinio paviršiaus, todėl užtikrinama geresnė dervos cemento adhezija. Kurdami PANAVIA™ V5, peržiūrėjome esamų PANAVIA™ gaminių cheminę sudėtį ir ją iš esmės atnaujinome. Technologija „Touch Cure“ taip pat buvo pritaikyta praimeriui „PANAVIA™ V5 Tooth Primer“ ir kartu naudojamai pastai „PANAVIA™ V5 Paste“. Cementuodami laminates su „PANAVIA™ Veneer LC“, dantims apdoroti naudojame ir praimerį „PANAVIA™ V5 Tooth Primer“. Šiame praimeryje taip pat naudojama technologija „Touch Cure“, kad adhezinė jungtis su dantimi būtų sukuriama nesumažinant cemento pastos veikimo laiko.

PAPILDOMI ADHEZINIAI MONOMERAI

Net ir adhezinių monomerų kūrimo srityje nesustojome vietoje: Sukūrėme IASi monomerą – ilgos anglies grandinės silano jungiamąją medžiagą, kuri suteikė galimybę integruoti keraminio praimerio funkciją į mūsų universalų savaiminės adhezijos dervos cementą „PANAVIA™  SA Cement Universal“. Šis monomeras pasižymi dideliu hidrofobiškumu, todėl užtikrina stabilų ir ilgalaikį surišimo stiprį. Apskritai galima teigti, kad surišimo patvarumas gali sumažėti dėl hidrolitinio skilimo reakcijos, pažeidžiančios stiklo keramikoje esančio silicio dioksido ir silano sujungimo medžiagų cheminį ryšį.

TRYS GAMINIAI, TENKINANTYS BEVEIK VISUS POREIKIUS

Sumaniai derindami šias technologijas ir sudedamąsias dalis sukūrėme dervos cemento asortimentą, kuris tenkina beveik visus poreikius. Naudojant PANAVIA™V5, „PANAVIA™ SA Cement Universal“ ir „PANAVIA™ Veneer LC“ galima gydyti įvairiausius atvejus. Šiais gaminiais galima cementuoti įvairių tipų restauracijas, protezus bei šakninius įklotus ir tinkamai naudojant pagal naudojimo instrukcijas pasiekti puikius rezultatus.

PANAVIA™ V5 yra dervos cementas, pasižymintis plačiausiu panaudojimo spektru iš visų trijų minėtų cemento sistemų. Jis apima beveik visus kitų dviejų cementų naudojimo būdus. Todėl gydytojas odontologas, atsižvelgdamas į klinikoje pasitaikančius atvejus ir paciento poreikius, gydymui gali pasirinkti tinkamą cemento sistemą iš šių trijų pagrindinių dervos cemento gaminių: PANAVIA™  V5 – dervos cementą, pasižymintį plačiu panaudojimo spektru; „PANAVIA™SA Cement Universal“ – paprastą ir lengvai naudojamą savaiminį adhezinį dervos cementą, ir „PANAVIA™Veneer LC“, kai reikia klijuoti laminates.

NAUJŲ GALIMYBIŲ TYRINĖJIMAS

Tokiose įmonėse kaip „Kuraray Noritake Dental“ geras dalykas yra tai, kad technologijų kūrimas neapsiriboja tik tam tikru gaminu ar gaminių grupe. Mokslinių tyrimų ir plėtros departamentas visada atlieka tyrimus, kaip panaudoti technologijų privalumus kitose srityse. Paimkime, pavyzdžiui, „KATANA™ Cleaner“, pradėtą gaminti 2019 m. Ši valymo priemonė gali būti naudojama seilėms, kraujui, laikinam cementui ar kitoms medžiagoms, kurios gali prilipti prie dantų ar protezų paviršių bandomojo primatavimo ir laikino cementavimo metu, pašalinti. Šis unikalus gaminys sukurtas pasinaudojant MDP monomero paviršiaus aktyvumo medžiagų funkcija.

IŠVADA

Dabartinio PANAVIA™ asortimento išskirtinumą daugiausia lemia mūsų ilgametės žinios ir patirtis tobulinant odontologinius dervos cementus ir adhezinius sprendimus. Mes žinome, kaip svarbu tobulinti esamas technologijas, nenustoti kurti naujų ir nuolat ieškoti geriausių būdų, kaip sujungti patikrintus ir naujus elementus, kad pasiektume geriausius įmanomus rezultatus. Kuriant gaminį atliekami klinikiniai bandymai ir renkami gydytojų odontologų atsiliepimai, siekiant atsižvelgti į ekstremalias burnos aplinkos sąlygas. Per 
pastaruosius 40 metų ši strategija pasiteisino ir esame tikri, kad ji mums padės sukurti daug kitų inovatyvių gaminių, idealiai padedančių gerinti pacientų burnos sveikatą.

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.

Vienos bendrovės iš esmės naudojasi kitų bendrovių sukurtomis pagrindinėmis technologijomis, kad galėtų tobulinti savo gaminius ir pristatyti naujus, o kitos pačios atlieka reikšmingus mokslinius tyrimus ir vysto technologijas. Ar šis skirtumas svarbus žmogui, kuris kasdien naudoja taip sukuriamus gaminius odontologijos kabinete ar laboratorijoje? Taip, nes bendrovės, gerai išmanančios pagrindines sudedamąsias dalis, chemiją ir technologijas, geba lanksčiai ir greitai spręsti iššūkius ir reaguoti į rinkos poreikius. Šiame straipsnyje aprašoma kelių pagrindinių „Kuraray Noritake Dental Inc.“ sukurtų technologijų įtaka netiesioginių restauracijų cementavimui.

Adhezinis cementavimas anksčiau ir dabar

Galimybė frezavimo būdu kurti dantų restauracijas iš įvairių rūšių keramikos atvėrė naujų galimybių dantų protezavimo srityje: galima gaminti ir naudoti labai estetiškas restauracijas. Šiame kontekste dažnai nepakankamai įvertinamas adhezinio cementavimo sistemų vaidmuo. O išties jos ne tik palaiko skaidrių dantų spalvos restauracijų estetinę išvaizdą, bet ir atveria kelią mažiau invaziniam preparavimui ir restauracijoms. Deja, ankstesnės sistemos, kuriose buvo numatyta cheminė dantų ir netiesioginių restauracijų adhezija, pasižymėjo netinkamomis ilgalaikėmis savybėmis ir būtinybe griežtai laikytis gamintojo rekomendacijų, o naudojimo procedūra buvo labai sudėtinga. „Kuraray Noritake Dental Inc.“ vystomos technologijos labai prisidėjo prie geresnio ilgalaikio sistemų surišimo efektyvumo ir paprastesnio naudojimo.

Ilgalaikio surišimo efektyvumo optimizavimas

Siekdama užtikrinti ilgalaikį ankstesnių cementavimo sistemų surišimą su danties struktūra (ypač dentinu), „Kuraray“ („Kuraray Noritake Dental Inc.“ pagrindinė bendrovė) XX amžiaus aštuntajame dešimtmetyje nusprendė pabandyti sukurti stipresnį adhezinį monomerą. Pirmas žingsnis siekiant tobulumo buvo fosfatų monomero fenil-P pristatymas 1976 m. Po penkerių metų, toliau tobulinant ir gerinant jo molekulinę struktūrą, buvo sukurtas populiarusis MDP monomeras, užtikrinantis ypač stiprų ir ilgalaikį surišimą su emaliu, dentinu, metalu ir cirkonio oksidu.

Išradimo sumanumą pabrėžia tai, kad šis monomeras tebėra visų „Kuraray Noritake Dental Inc.“ adhezyvų ir adhezinių cementų dalis, be to, jį naudoja ir kiti gamintojai, siekdami optimizuoti savo gaminių surišimo stiprumą ir ilgaamžiškumą. Palyginti su kitur susintetintu MDP, autentiškas „Kuraray Noritake Dental Inc.“ MDP monomeras išsiskiria neprilygstamu grynumu. Nepriklausomi tyrimai rodo, kad toks grynumo lygis turi teigiamą poveikį surišamosioms savybėms1. Dėl MDP monomero stabilumo drėgnoje aplinkoje gaminiai, kurių sudėtyje jo yra, laikosi stabiliau.

Skirtingi MDP monomerai pasižymi skirtingu grynumu ir skirtingu surišimo efektyvumu.

Buvo paruošti trys eksperimentiniai savaiminio ėsdinimo praimeriai, sudaryti iš 15 % 10-MDP masės ir gauti iš skirtingų šaltinių: KN („Kuraray Noritake Dental“), PCM (Vokietija) arba DMI („Designer Molecules Inc.“, JAV). Informaciją suteikė gyd. Kumiko Yoshihara.

Vis dėlto tam, kad adhezinės dervos cementas užtikrintų tvirtą surišimą ir išskirtinį kraštinį sandarumą, nepakanka vien adhezinio monomero. Būtina ir veiksminga šio monomero polimerizacija, o ją pasiekti ne visada lengva. Siekdama užtikrinti veiksmingą PANAVIA™ V5 kietinimą šviesoje ir tamsoje, „Kuraray Noritake Dental Inc.“ sukūrė technologiją „Touch- Cure“. Pagrindinė šios technologijos dalis – dantų praimerio PANAVIA™ V5 sudėtyje esantis naujai sukurtas labai aktyvus polimerizacijos akceleratorius, kuris yra suderinamas su rūgštiniu MDP monomeru ir skatina polimerizaciją nuo danties ir cemento ribos, kai tik PANAVIA™ V5 pastos užtepama ant praimeriu jau padengto danties paviršiaus. „PANAVIA™ Veneer LC“ – šviesoje kietėjančiame dervos cemente, kuris veikia su tais pačiais praimeriais – ir „PANAVIA™ V5 Tooth Primer“ sudėtyje esantis polimerizacijos akceleratorius pasižymi tuo pačiu veikimo mechanizmu. Jis prisideda prie adhezinio paviršiaus polimerizacijos, o „PANAVIA™ Veneer LC“ pasta pasižymi puikiu stabilumu aplinkos šviesoje ir polimerizuojasi kietėdama šviesoje.

Pavyzdžiui, šis reiškinys buvo vertinamas su PANAVIA™ F2.0, kuris yra PANAVIA™ V5 pirmtakas. Tyrimo rezultatas: PANAVIA™ F2.0 pasižymėjo daug geresnėmis kraštų sandarinimo savybėmis nei kitos vertintos cemento sistemos2. Dėl šio dokumentuose užfiksuoto saugaus paviršiaus sandarinimo rečiau pasitaiko kraštinis pralaidumas, užtikrinamas labai didelis polimerizacijos lygis net ir savaiminio kietėjimo režimu (be kietinimo šviesa arba kai šviesą užstoja restauravimo medžiaga), todėl surišimas yra ypač tvirtas.

Papildoma polimerizacijos akceleratoriaus nauda – tai, kad jis veikia kaip stiprus reduktorius. Jis neutralizuoja natrio hipochloritą, kuris paprastai naudojamas kaip irigacinis tirpalas per endodontinio gydymo procedūras, ir taip panaikina jo neigiamą poveikį vėliau užteptos cemento pastos surišimo stiprumui.

Supaprastintas stiklo keramikos cementavimas

Tam, kad reikėtų mažiau buteliukų, mažiau etapų ir būtų paprastesnės cementavimo procedūros, šio amžiaus pradžioje buvo sukurti ir pradėti naudoti savaiminės adhezijos dervos cementai. Visgi daugumos šių produktų indikacijų diapazonas yra nedidelis. Jie gerai tinka cirkoniui, metalui, emaliui ir dentinui, tačiau nerekomenduojami stiklo keramikai klijuoti (nebent būtų naudojamas papildomas silano praimeris). PANAVIA™ SA universalus cementas, kurio sudėtyje yra MDP, skiriasi dėl kitos „Kuraray Noritake Dental Inc.“ patentuotos technologijos: IASi monomero – ilgos anglies grandinės silano jungiamosios medžiagos. Šis monomeras sukuria stiprų cheminį ryšį su kompozito derva, porcelianu ir silicio dioksido tipo keramika (pvz., ličio disilikatu), todėl nereikia atskiro silano komponento (praimerio arba adhezyvo). Dėl šios technologijos privalumų PANAVIA™ SA universalus cementas aiškiai išsiskiria iš kitų savaiminės adhezijos dervos cementų kaip tikra vieno komponento cementavimo sistema, tinkama net ir iš stiklo keramikos pagamintoms restauracijoms.

Jei pageidaujama, gaminio surišimo su danties struktūra stiprumą galima padidinti naudojant populiarų universalų adhezyvą „CLEARFIL™ Universal Bond Quick“, pasižymintį greito surišimo technologija. Šią technologiją „Kuraray Noritake Dental Inc.“ sukūrė siekdama išspręsti problemas, susijusias su lėtu įsiskverbimu į danties struktūrą, ypač į drėgną dentiną, būdingu universaliems adhezyvams. Kad šie adhezyvai tinkamai įsiskverbtų, juos reikia ilgai aktyviai trinti į danties struktūrą arba prieš kietinant šviesa kurį laiką palaukti. Iš originalaus MDP monomero ir hidrofilinių amidinių monomerų sudaryta patentuota greito surišimo technologija pasižymi didele trauka vandeniui, todėl į drėgną dentiną įsiskverbia greitai ir giliai. Taigi darbas sutrumpėja ir supaprastėja, bet tai neturi neigiamos įtakos surišamosioms savybėms.

Išvada

„Kuraray Noritake Dental Inc.“ sukurtos technologijos reikšmingai prisidėjo prie geresnių adhezinių cementavimo sistemų surišamųjų savybių ir tikrai universalaus savaiminės adhezijos dervos cementų naudojimo. Bendrovė siūlo supaprastintą aukštos kokybės dervos cementų asortimentą, skirtą kiekvienam vartotojui ir tipiškoms klinikinėms situacijoms. Sudedamųjų dalių ir veiksmų reikia mažiau, o procedūros yra paprastesnės – padaroma mažiau klaidų ir gaunamos estetiškos ilgalaikės restauracijos. Be privalumų, susijusių su technologijomis, minėti gaminiai turi daug papildomų naudingų savybių. Išsamų aprašymą rasite internete adresu kuraraynoritake.eu.   

Literatūra

*) 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.
**) 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

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.

Alexander (Alek) Aronin is a master dental technician who dedicated himself to the creation of high-end, handmade porcelain restorations. He runs a dental laboratory and morphology school in Spain, and travels the world as a lecturer and teacher.

The greatest source of inspiration in his professional life is the book Collection of Ceramic Works by Hitoshi Aoshima. Through reading it in 1996, he discovered superb outcomes of working with dental ceramics. Moreover, the book’s content made him realize that the creation of handmade porcelain work is a result of special education and manual skills. Those who want to become masters need a lot of commitment and a striving for continuous improvement, which Alek shows in his work and his classes. We talked to him about his philosophy and his enthusiasm for the creation of lifelike restorations. He shared with us his perspective on the future of dental technology and gave some practical tips on how to achieve a high level of professional satisfaction.

Photo courtesy of Dennis Debiase

Alek, many dental technicians decide to focus on CAD/CAM technology and automated processing of dental ceramics. Due to improvements on the material side, a handmade porcelain layer is no longer necessary in many clinical cases. In this context, the manual refinement process is reduced to a minimum. Why did you decide to take a completely different path and focus on fully manual dental craftsmanship?

The shift towards automated processing is not a matter of choice for dental technicians rather, it is a natural response to the evolution of technology. The high-end manual refinement process remains unchanged. The human element, from communication to hand crafting among skilled individuals and demanding clients, has been a constant so far throughout history. This traditional connection remains stable for centuries.

Digitalisation is not the revolution in the dental industry, and I do not see the benefit of it in our narrow specialization yet. In the area we are working, we do all steps of our case faster, incomparably more precise and more profitable. But we are keeping eye on machines and waiting for a suitable one.

Machines and automated processes widely serve mass production businesses focused on fast, affordable and uniform results in a highly competitive field. Our goal and workflow are different - we provide individual work and personal attention to each of our partners and patients.

So, we do not compete with the production labs and do not interrupt each other, we coexist in parallel worlds as always. A small number of dentists and their patients will always demand personal attention and valued restorations and service of the highest quality.

Many dental technicians admire your work. Yet, you continue to strive for improvement. Why is this the case?

On one side, we are limited by static ceramic material used to mimic dynamic natural teeth that keep changing for a lifetime. On the other side, we are limited by our manual skills. I am still far away from my teachers and Japanese colleagues. My target is to improve the fabrication process. My goal is to achieve the simplicity and imperfectness like Aoshima-sensei.

Alek lecturing at the IDS 2023 in Cologne.
Photo courtesy of Dennis Debiase

We are enjoying the outcome, but prefer to focusing on the improvement of the process, and move on to create a better one. This is what I am learning in Japan, and this is what I teach my students.

Talking about learning: What are the most important aspects a dental technician who wants to improve his skills should have in mind when looking for a good teacher?

Manual skills are very important, but not the only aspect that should be taken into account. Every individual should be motivated and guided and this is a teacher’s job.

I love the traditional Japanese way of teaching and learning: The teachers are passionate, leading the way by evoking emotions and manual skills to bring the best out of every single student. My personal advice for dental technicians who want to become masters in the creation of lifelike high-end dental restorations is to select their teachers carefully and go to a private school or courses whenever they have the chance.

What are the most important tools a dental technician needs to use when trying to create high-end lifelike restorations?

I suggest to focus on four aspects:

1. Documentary dental photography - required for documentation and communication with the dental office and patients using constant (once set and never changed) parameters of the photo equipment.
2. Focus to the biomimetic additive dentistry. This is a minimum machine invasive field. Dental technicians and dentists should be able to develop a deep knowledge about clinical and lab-side procedures to be able communicate with each other.
3. Mastering morphology and function (shape carving), and anatomy (internal staining), which comes with value control and mimicking fine tooth details for best integration in the mouth.
4. Written communication (stop phone calls) is very important, this is the way how to exchange the information between the patient, clinic and lab by strict protocols.

I teach these complex skills in my morphology school and in many of my trainings worldwide. Focusing on the four aspects, a dental technician has a great chance to become a good specialist in a relatively short period of time in a narrow field.

Is material selection important for achieving great results?

I’ve been using Noritake ceramic for most of my life, and the reason is simple: Noritake created their EX-3 porcelain over 40 years ago, and it was so well-made that it has not needed any changes since.

This is showing their consistently high quality and creates unbroken succession in the valuable tradition of passing on techniques and knowledge.

Today, among different generations of dental technicians, we can use and share the same methods, vocabulary and abbreviations, powders, and temperature charts developed by our skilled teachers 30 to 40 years ago. This unique feature sets Noritake and Creation porcelains apart from all other brands and systems in the world.

The other Noritake porcelain I use quite frequently is CERABIEN™ ZR, which is also well-tried and tested and has even some more advantages than EX3.

Is there any final advice you would like to give?

To become a good professional, I suggest to developing in four parallel directions:

1. Practicing on phantoms - fabricating cases and ceramic samples. It helps to experiment and practice with varied materials and techniques.
2. Implementing the achieved techniques in clinical cases.
3. Working with case presentation PowerPoint or Keynote: documenting the working steps in pictures and videos from beginning to end.
4. Mastering the communication using e-mails. Constantly calibrate and adjust the information exchange process between the clinic and lab. Acquire deeper knowledge about the work of each other.

Good luck!

Vienos bendrovės iš esmės naudojasi kitų bendrovių sukurtomis pagrindinėmis technologijomis, kad galėtų tobulinti savo gaminius ir pristatyti naujus, o kitos pačios atlieka reikšmingus mokslinius tyrimus ir vysto technologijas. Ar šis skirtumas svarbus žmogui, kuris kasdien naudoja taip sukuriamus gaminius odontologijos kabinete ar laboratorijoje? Taip, nes bendrovės, kurios viską kuria nuo nulio, paprastai turi didesnį supratimą apie gaminius ir jų gamybos procesus, todėl joms lengviau keisti konkrečias savybes, spręsti problemas ir reaguoti į rinkos poreikius. Šiame straipsnyje aprašoma kelių pagrindinių „Kuraray Noritake Dental Inc.“ sukurtų technologijų įtaka tiesioginių kompozito restauracijų darbo eigai.

Tiesioginės restauracijos – nuo sudėtingų iki paprastų

Adhezinė restauracinė odontologija, kurios procedūroms naudojami aukštos kokybės adhezyvai ir dervos kompozitai, yra vienas populiariausių ėduonies pažeistų dantų gydymo būdų. Šiuo metu, norint sukurti gražų ir patvarų rezultatą, paprastai pakanka vieno buteliuko universalaus adhezyvo ir vieno ar dviejų atspalvių ir matiškumo variantų universalaus kompozito, jei pasirenkamos tinkamos medžiagos. Visgi taip buvo ne visada. Ilgą laiką tiesioginės dantų restauracijos metodai buvo gana sudėtingi: adhezyvai buvo ilgo aplikacijos laiko, kelių buteliukų ir etapų sistemos, kurias reikėjo naudoti griežtai pagal gamintojo rekomendacijas. Kita vertus, realistiškas rezultatas naudojant kompozitines restauracijų medžiagas pasiekiamas tik tuomet, kai tinkamai derinami įvairūs atspalviai ir matiškumo variantai. Net jei sudėtingos procedūros būdavo atliekamos taisyklingai, išlikdavo palyginti didelė mikropralaidumo, spalvos pasikeitimo ir galiausiai antrinio ėduonies atsiradimo rizika. „Kuraray Noritake Dental Inc.“ gana anksti susitelkė į šių problemų sprendimą, pradėdama nuo 1981 m. sukurto originalaus MDP monomero naudojimo

Surišimo efektyvumo optimizavimas

Pirmasis MDP monomeras išsprendė nepakankamai gero ilgalaikio surišimo naudojant adhezines sistemas problemą. MDP hidrofilinė (fosfatinė) grupė sukuria ypač stiprią ilgalaikę cheminę jungtį su kalciu, esančiu hidroksiapatite – pagrindinėje emalio ir dentino sudedamojoje dalyje. Susiformavusi MDP Ca druska yra stabilaus, stipraus ir patvaraus hibridinio sluoksnio pagrindas. Adhezyve yra ir dervos, tad po kietinimo šviesa ertmė užsandarinama itin patikimai. Iki pat šių dienų MDP yra pagrindinis visų „Kuraray Noritake Dental Inc.“ adhezinių gaminių komponentas. O „CLEARFIL™ SE Bond“ dėl jo tapo savaiminio ėsdinimo adhezijos sistemos auksiniu standartu.

Vis dėlto bendrovė „Kuraray Noritake Dental Inc.“, tvirtai tikėdama, kad adhezyvai turėtų užtikrinti ne tik tvirtą ir ilgalaikį surišimą, ėmėsi spręsti dar vieną problemą – demineralizacijos ir ertmės susidarymo riziką, kurią sukelia ertmėje likusios bakterijos. Remdamasi patirtimi, įgyta kuriant kitus adhezyvų monomerus, „Kuraray Noritake Dental Inc.“ išrado MDPB monomerą, pasižymintį antibakteriniu ertmių valymo poveikiu. Skirtingai nuo antibakterinių medžiagų, kurios gali sumažinti po to naudojamų adhezyvų surišimo stiprumą, MDPB monomeras likusias bakterijas sunaikina nekeisdamas surišamųjų savybių. Šio monomero yra dviejų buteliukų savaiminio ėsdinimo adhezyvo „CLEARFIL™ SE Protect“ praimerio sudėtyje. Jis yra užfiksuotas polimerizacijos būdu.

Manoma, kad MDPB baktericidinis mechanizmas yra panašus į gerai žinomos antibakterinės medžiagos CPC (cetilo piridinio chlorido), kurios yra daugelio dantų pastų ir burnos skalavimo skysčių sudėtyje.

Adhezijos procedūrą jau supaprastino dviejų buteliukų savaiminio ėsdinimo adhezyvai, o vieno buteliuko universalūs klijai – dar labiau. Viename buteliuke suderinti sudedamąsias dalis, paskirstytas daugiapakopėse sistemose, nepakenkiant gaminio stabilumui yra iššūkis. Dabartinės technologijos leidžia tai padaryti. Kad paviršius būtų užsandarinamas kuo greičiau po užtepimo, monomerų skverbimasis į danties audinius turi būti greitas ir veiksmingas. Vis dėlto monomerai paprastai lėtina įsiskverbimą: jiems reikia laiko įsiskverbti į danties struktūrą, ypač į drėgną dentiną, o kartais tenka net įtrinti. Todėl „Kuraray Noritake Dental Inc.“ sutelkė dėmesį į „Rapid Bond“ technologijos kūrimą. Ją sudaro originalus MDP monomeras, sujungtas su naujai sukurtais susisiekiančiais hidrofiliniais amidiniais monomerais ir integruotas į „CLEARFIL™ Universal Bond Quick“. Hidrofiliniai amidiniai monomerai greitai, giliai ir visiškai įsiskverbia į dentiną, o kietėdami sudaro tankų polimerinį tinklą, kuris užtikrina tvirtą ir ilgalaikį surišimą. Taigi nereikia laukti ir trinti, o po kietinimo šviesa ertmė yra užsandarinta patikimai ir ilgam.

Dėl savo hidrofiliškumo (traukos vandeniui) „Rapid Bond“ technologijos amidiniai monomerai labai gerai įsiskverbia į dentiną. Po kietinimo šviesoje surišimas pasižymi maža vandens absorbcija, todėl yra itin atsparus senėjimui.

Tiesioginių restauracijų optimizavimas

Derinami keli sluoksniai, atspalviai ir matiškumo variantai. Laimei, daugelyje klinikinių situacijų labai sudėtingų sluoksniavimo metodų naudojimas kuriant tikroviškas kompozito restauracijas yra praeitis. Priežastis – ištobulinti dervos kompozitai, nepastebimai susiliejantys su greta esančia danties struktūra. Siekdama užtikrinti šią palankią savybę, „Kuraray Noritake Dental Inc.“ sukūrė patentuotą šviesos difuzijos technologiją (ŠDT). Ši technologija integruojama į specialias iš anksto polimerizuotas užpildo daleles, kurios veikia kaip milijonai mikroprizmių, praleidžiančių ir laužiančių šviesą ir atspindinčių spalvą iš aplinkinės danties struktūros. Užpildo dalelės, kurių dydis, pasiskirstymas ir lūžio rodiklis optimizuoti matricos atžvilgiu, garantuoja neprilygstamą natūralų susiliejimą. Ši patentuota užpildų technologija integruota į visus serijos CLEARFIL MAJESTY™ kompozitus. Naujausias gaminys – „CLEARFIL MAJESTY™ ES-2 Universal“, kuriame „Kuraray Noritake Dental Inc.“ panaudojo kito lygio ŠDT – išsiskiria vieno atspalvio technika ir supaprastintu atspalvio pasirinkimu: yra du atspalviai priekinei ir vienas atspalvis galinei daliai, tačiau jie taip gražiai susilieja, kad padengia beveik visus VITA klasikinių A1–D4 atspalvių paletės atspalvius.

Tinkamas laužimas ir šviesos pralaidumas, siekiant puikios optinės integracijos: „Kuraray Noritake Dental Inc.“ gaminamos šviesą sklaidančios užpildo dalelės „CLEARFIL MAJESTY™ ES-2“.

Kadangi puiki išvaizda priklauso ne tik nuo optinės integracijos ir nepastebimų restauracijos kraštų, „Kuraray Noritake Dental Inc.“ taip pat sukūrė užpildo daleles, kurios užtikrina visa kita – natūralų paviršiaus blizgesį ir ilgalaikį poliravimo rezultato išlaikymą. Trijų klampumo lygių medžiagoje „CLEARFIL MAJESTY™ ES Flow“ integruotas sprendimas vadinamas submikroninių užpildo dalelių technologija. Šios užpildo dalelės – tokios mažos, kad šviesos atspindžiai palaiko natūralų vaizdą net kai restauracija nusidėvi. Išskirtinė „Kuraray Noritake Dental Inc.“ silano technologija naudojama tam, kad milijonai submikroninių užpildo dalelių būtų sujungiamos ir laikui bėgant išlaikomos neatsiskyrusios. Tai leidžia mažo klampumo kompozitus užpildyti dideliu kiekiu dalelių ir taip apriboti vandens įgertį, kuri priešingu atveju sukeltų sukietėjusio kompozito irimą. Tobula blizgių submikroninių užpildo dalelių, šviesą sklaidančių užpildo dalelių, dervos matricos ir patentuotos silano technologijos pusiausvyra sukuria subalansuotą mechaninių ir optinių savybių derinį.

„CLEARFIL MAJESTY™ ES-2 Universal“ vieno atspalvio restauracijos pavyzdys.

Išvada

Adhezyvo monomerai, užpildo dalelių technologijos ir silano technologija, užtikrinančios tvirtą užpildo dalelių, klasterių ir dervos matricos derinį, liudija, kad bendrovė „Kuraray Noritake Dental Inc.“ yra patikima adhezinių restauracijų ekspertė. Pastaraisiais dešimtmečiais sukurtos patentuotos technologijos neabejotinai prisidėjo prie geresnių (ilgalaikių) tiesioginių restauracijų, taip pat patikimo ir lengviau pasiekiamo estetinio rezultato.

Interview with Mitsunobu Kawashima
Manager, Technology Division of Kuraray Noritake Dental Inc.

In 1983 – exactly 40 years ago – PANAVIA™ EX was introduced in Japan as the first product of the PANAVIA™ family and the first product containing the original MDP monomer. Since then, the PANAVIA™ family of resin cements has been continuously expanded by developing new resin-cement materials that are precisely adjusted to the contemporary demands of dental practitioners. The current line-up of easy-to-use, high-performance adhesive luting materials is globally available and used by dental practitioners with high quality standards.

We had a conversation with Mr. Mitsunobu Kawashima about PANAVIA™ EX as a ground-breaking innovation in the field of dental resin cements and subsequent steps toward the current well-balanced resin cement portfolio. He is currently responsible for the development of chair-side materials in the Technology Division of Kuraray Noritake Dental Inc. (Kuraray Noritake Dental) and has been part of the team developing the many products of the PANAVIA™ family for more than 30 years.

The resin cements developed by the company before the introduction of PANAVIA™ EX contained the adhesive monomer Phenyl-P. Why did you decide not to use Phenyl-P in the new formulation?

At the time we decided to develop PANAVIA™ EX, we were engaged in the development of new adhesive monomers to replace Phenyl-P. The main aim of this project was an improvement of our products’ bond strength to metal alloys and dentin. Among the new adhesive monomers being developed, we decided to use the MDP monomer, because it features excellent bonding to tooth structure and metal alloys used in dentistry, as well as superb resistance to water. Incidentally, our first products to contain the original MDP monomer were the resin cement PANAVIA™ EX and the bonding agent CLEARFIL™ NEW BOND.

Where did the name PANAVIA™ come from?

The name “PANAVIA™” is a compound word consisting of “PAN” and “VIA”. The former is of Greek origin, and the latter is of Latin origin. “PAN” means “everything” and “VIA” means “way” or “method”. Consequently, the name “PANAVIA” describes a “method for bonding everything”; it represents our desire to have products launched under the umbrella of the PANAVIA™ brand recognized as dental materials that can bond to all types of restoration and tooth structure.

Would you please tell us the story behind the development of PANAVIA™ EX?

Back in the early 1980s, it was indispensable for us to develop new adhesive monomers as a part of our project to develop a new resin cement with unprecedented adhesive properties. In this context, we conducted a comprehensive literature search for compounds thought to be involved in adhesion. At the same time, we carried out a variety of R&D activities, including basic research to quantitatively clarify the relationship between the molecular structures of monomers and their adhesive qualities, synthesis trials of various monomers and bond strength tests. Consequently, we succeeded in developing the MDP monomer that had the physical properties we were working to obtain. Following the development of that MDP adhesive monomer, we were finally able to create PANAVIA™ EX in our laboratory. In early 1982, we completed the first prototype of PANAVIA™ EX for external evaluation and asked a dental college in Japan to evaluate it. He found that the prototype cement might cure too quickly in clinical use. This was due to the fact that we had not taken into account the difference between room temperature and intraoral temperature, which has a huge impact on the curing time. This error led us to recognize how important clinical evaluations are during the development of dental materials. To this day, we continue to place great importance on the opinions of clinicians whenever a new material is being developed.

The name “PANAVIA™” is a compound word consisting of “PAN” and “VIA”. The former is of Greek origin, and the latter is of Latin origin. “PAN” means “everything” and “VIA” means “way” or “method”.

What were the key technological features of this new PANAVIA™ EX cementation system?

The system had five key features: Appropriate film thickness, appropriate flow properties of the paste, radiopacity, improved bond strength and improved surface-cure characteristics. At the time that PANAVIA™ EX was developed, a film thickness of 30 μm or less was desired for luting cements. The largest components we wanted to use in the formulation – the silica filler particles present in our composite resin – had a maximum particle diameter of 50 μm. We were able to achieve a film thickness of 30 μm or less by significantly extending the silica grinding time, which made the filler particles much finer. An appropriate paste consistency – a low level of viscosity and good flowability – was achieved by using low-viscosity monomers for PANAVIA™ EX. In order to make the cement radiopaque, we dispersed radiopaque filler within the powder component. In fact, we were convinced that it was essential to be able to check for the presence of excess cement under the gingival margins after a restoration was placed. The increase in bond strength was achieved by blending the MDP monomer into the liquid component.

What about the surface-cure characteristics of the cement?

Every dental practitioner knows that the surface of resin cements must be protected from oxygen in the air in order to cure properly. For this purpose, we developed OXYGUARD, a water-soluble gel material. It is applied to the restoration margins to cover the unpolymerized resin cement surface and protect it from exposure to oxygen. In this way, the formation of an oxygen inhibition layer – a layer of uncured resin on the surface that compromises the marginal integrity of the restoration – is prevented and an intact, fully polymerized cement surface can develop. In this way, the use of OXYGUARD has contributed greatly to improving the cure characteristics of cements.

What do today’s PANAVIA™ products and PANAVIA™ EX have in common?

The PANAVIA™ family of products, including PANAVIA™ EX, share the concept of “being a resin cement product that opens new dimensions in dentistry”. PANAVIA™ EX was our first resin cement, and it was conceived as a cement for a new era. It can bond to tooth structure and dental metals very well, thanks to the use of the MDP monomer. This important adhesive monomer is still used today in many of our products. Ever since the launch of PANAVIA™ EX, Kuraray Noritake Dental has continued to take on new challenges and has developed many new products in the growing PANAVIA™ family. These include PANAVIA™ 21, a cement in paste form that has a self-etching primer as an accessory; PANAVIA™ Fluoro Cement, a dual-cure cement paste that releases fluoride; and PANAVIA™ F2.0, which can be used with an LED curing unit. The current portfolio consists of PANAVIA™ V5, which features the substantially improved bonding performance that was achieved after a major review of the basic composition of the series, PANAVIA™ SA Cement Universal, which works as a standalone product without separate primers, and PANAVIA™ Veneer LC, PANAVIA™ family’s latest product. The latter is a light-curing resin cement with the specialized purpose of bonding laminate veneers.

In retrospect, what did the introduction of PANAVIA™ EX mean to Kuraray Noritake Dental?

In the development of new resin cements, it is important to quickly respond to the rapidly changing trends in the market. Whenever new prosthodontic treatment concepts appear – like adhesive bridges as a minimally invasive treatment option replacing a single tooth – or new restorative materials are introduced, such as different types of ceramics – we need to check if our resin cement systems are compatible with the tasks that come with these changes, as well as possibly developing new ones. Following the launch of PANAVIA™ EX, we received a wide range of feedback from experts working at dental clinics and laboratories. We leveraged this feedback in subsequent development projects, always striving to stick close to the clinical setting. After Kuraray Medical Inc. merged with Noritake Dental Supply Co., Limited, this ethos was embedded in the work ethic of all employees of Kuraray Noritake Dental.

Can you give us a brief history of the PANAVIA™ EX journey to the currently available PANAVIA™ family portfolio?

Since the launch of PANAVIA™ EX 40 years ago, six different PANAVIA™ products have been released. Each of them has received high acclaim for their unique features, both in the Japanese resin cement market and abroad. For 40 years, we have been improving PANAVIA™ in response to the demands of the times. We developed a product with increased adhesion when non-retentive preparation designs (adhesive bridges) and smaller bonding surfaces (due to less invasive preparations) became popular. And for users concerned about secondary caries, we developed a material with fluoride-releasing properties. At the same time, we focused strongly on making dental cementation easier by finding ways to make our resin cements bond well to various types of crown-restoration materials, including precious metals and ceramics. During these drives towards improvement, “achieving reliable general luting” has always been at the forefront of our goals. We believe that the successful evolution of the PANAVIA™ brand owes a great deal to our incessant efforts to obtain a high level of bond strength to dentin after chemical polymerisation”.

How did the R&D department evolve over the years?

Initially, our efforts in the development of dental materials had focused on bonding agents and restorative composite resins. PANAVIA™ EX was just one of our new development projects and only a few staff members were assigned to that product. After PANAVIA™ EX was launched in 1983 and it was accepted worldwide, our product line-up of resin cements was expanded considerably. Consequently, we have increased the number of development staff assigned to resin cements and set up a special development team responsible for the self-adhesive resin cement product line that includes PANAVIA™ SA Cement Universal. As a result, the size of the team assigned to resin cements has expanded substantially.

How did production change?

When PANAVIA™ EX was launched in 1983, the product was manufactured exclusively for the Japanese market in a relatively small facility. Today, in order to produce all products of the PANAVIA™ family for the global market, we have automated our production facilities and increased the production equipment and systems dedicated to producing the resin cement paste. To support our product quality, we have also set up a quality control system that assures we turn out safe and high-quality products, drawing on over 40 years of technical knowhow and experience in the production of resin cements.

For 40 years, we have been improving PANAVIA™ in response to the demands of the times.

When did external researchers start showing interest in PANAVIA™?

The development of PANAVIA™ EX was carried out with the active participation of researchers at a dental college in Japan, involving such activities as performing basic adhesion tests and experimenting with clinical applications using adhesive bridges. At that time, resin cements that provided a strong bond to tooth structure or metal alloys were not widely used. I believe that overseas researchers were interested in the development of PANAVIA™ EX at a relatively early stage, for this reason.

What current concept do you have in mind as you continue developing your adhesive cements?

We have two basic central concepts: “Achieving greater bond strength” and “Delivering easier handling characteristics”. I think that the shades of resin cements are also devised in each product in order to get the most of the characteristics of aesthetic restorative materials. At our company, we have embodied “achieving greater bond strength” in PANAVIA™ V5, and “delivering easier handling characteristics” in PANAVIA™ SA Cement Universal. We will continue to explore the development and introduction of various new technological applications, to bring even higher performance products to market.

What do you think is the strength of Kuraray Noritake Dental’s R&D team?

We conduct R&D activities continuously, focusing on the development of luting materials. In our product development department, the same person is often responsible for one product category over long period of time. For example, I have been engaged in the development of PANAVIA™ products for much of my time with the company. The result is that each person in the development department can be said to be an expert in a certain category of products. They leverage the technical knowledge acquired in the past for the development of new products, resulting in entirely new discoveries.

Do you have any ideas about what the future of PANAVIA™ will be?

We will continue to focus on the development of even simpler, easier-to-use resin cements suitable for a wide range of applications – products based on the concept of universality. This should allow users to focus more on the actual treatment than ever before, while of course delivering a strong and durable bond between the tooth structure and the restoration.

MITSUNOBU KAWASHIMA

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.