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TIPS AND TRICKS

Case by MDT Daniele Rondoni and MDT Roberto Rossi

Recently, Kuraray Noritake Dental Inc. has introduced Esthetic Colorant for KATANA™ Zirconia – dyeing liquids applied after milling of the company’s multi-layered zirconia. Enthusiastic users of the KATANA™ Zirconia Multi-Layered Series may wonder when and how to use the innovation: In combination with external stains, veneering porcelains or liquid ceramics, or as a replacement of those products? On the monolithic surface or on a dentin structure (framework)? And how much liquid produces the desired effect? Some technical guidance is provided in this article.

The good news: Esthetic Colorant fits perfectly into any existing approach, no matter whether you prefer a full-contour or cutback design. You may apply the liquids solely in a zero-bake technique – just individualize the milled restorations with Esthetic Colorant, fix the colours during the final sintering procedure and polish the surface. On the other end of the spectrum of options is the use underneath different layers of internal stains, porcelains and glaze.

WE UTILIZE ESTHETIC COLORANT MAINLY FOR THREE PURPOSES:

1. To add specific individual characteristics to the restoration, which are not generated by the multi-layered material structure, yet difficult to create with internal stains (examples are a more chromatic body area of a canine in comparison to the adjacent lateral incisor or pronounced mamelon structures). As the liquids diffuse into the structure, a depth effect is created.
   
   Eight liquids are available for the abovementioned purpose: A, B, C and D Plus for changing the brightness and creating shadows, BLUE, GRAY, ORANGE and BROWN for general characterization.

2. To pre-treat tissue areas to produce a perfectly shaded basis for the application of liquid ceramics (CERABIEN™ ZR FC Paste Stain) or Tissue Porcelain.
   
   Two liquids are available for this purpose: PINK AND VIOLET.

3. To prevent a greyish effect caused by the shining through of discoloured abutment teeth or metal parts (posts or implant abutments) – in this case, Esthetic Colorant OPAQUE or WHITE is applied to the intaglio of the restoration. The effect: the incoming light is blocked on the side of the dark element, while the natural translucency in the outer surface area of the restoration is maintained.

PURPOSE 1

An example of how to add specific individual characteristics to the surface of the restoration is the following full-arch case. After sintering, we just added a micro-layer of CERABIEN™ ZR Luster Porcelain and CERABIEN™ ZR FC Paste Stain Clear Glaze.

Fig. 1a. Frontal view of the complex restoration made of KATANA™ Zirconia HTML Plus after milling and the application of different shades of Esthetic Colorant.

Fig. 1b. Occlusal view of the complex restoration after milling and the application of different shades of Esthetic Colorant. Important: Every restoration characterized with Esthetic Colorant should be left to dry for at least 30 minutes prior to sintering.

Fig. 1c. Frontal view of the restoration after the final sintering procedure.

Fig. 1d. Occlusal view of the restoration after sintering.

Fig. 1e. Addition of a micro-layer of CERABIEN™ ZR Luster Porcelain.

FINAL SITUATION

Fig. 1f. Frontal view of the definitive restoration finished with CERABIEN™ ZR FC Paste Stain Clear Glaze.

Fig. 1g. Occlusal view of the final restoration.

Fig. 1h. Great incisal translucency.

PURPOSE 2

The effect of a pre-treatment of the tissue area of a complex restoration is illustrated with the aid of the following example case. Again, we opted for a nearly monolithic design with a minimal cutback in the incisal area of the teeth. The appearance of the originally tooth-coloured tissue area is modified visibly through the application of Esthetic Colorant in the shades PINK and GRAY. Some individual effects are added to the teeth as well.

Fig. 2a. Vestibular view of the milled restoration (material: KATANA™ Zirconia YML).

Fig. 2b. Palatal view of the milled restoration.

Fig. 2c. Vestibular pattern of application of Esthetic Colorant.

Fig. 2d. Palatal pattern of application of Esthetic Colorant.

Fig. 2e. Vestibular view of the restoration after the final sintering procedure.

Fig. 2f. Palatal view of the restoration after the final sintering procedure.

PURPOSE 3

Comparison of restorations on an implant abutment with and without Esthetic Colorant (EC):

HOW TO APPLY ESTHETIC COLORANT?

Essentially, Esthetic Colorant may be applied with any metal-free brush or pen. In our opinion, the best results are obtained by using the Liquid Brush Pen that has been specifically developed for the dyeing liquids. The pen’s housing is filled with the selected shade of Esthetic Colorant and allows for a controlled application, as the tip always dispenses the right amount of liquid and does not dry out. We utilize a separate Liquid Brush Pen for every shade that is frequently in use.

SINTERING PARAMETERS

After drying, which is essential for a good outcome, the restorations treated with Esthetic Colorant may be put into the sintering furnace and sintered according to the schedule recommended for the KATANA™ Zirconia Multi-Layered series. The parameters do not need to be adjusted.

CONCLUSION

The controlled application of Esthetic Colorant is easily accomplished by using the appropriate equipment, while the desired effects are obtained predictably. The liquids’ ease of use, the appropriate number of shades available and the achievable effects are just a few of the many benefits you will find when trying out the new system in your dental laboratory.

Dentists:

É possível reduzir o número de cimentos utilizados num consultório dentário? Na maioria dos casos, sim. A Kuraray Noritake Dental Inc. está convencida de que três sistemas de cimentação são suficientes para cobrir todas as indicações e todas as necessidades de cimentação. A escolha dos produtos pode variar consoante as preferências pessoais e o foco em tratamentos dentários específicos.

É por isso que a empresa oferece três cimentos de resina de alta qualidade, com os quais podem ser satisfeitas as necessidades e desejos de cada dentista e paciente. Está disponível um cimento para aqueles que desejam manter a máxima simplicidade enquanto tiram partido das muitas vantagens que os cimentos de resina oferecem em relação aos cimentos convencionais. Outro sistema foi concebido para quem necessita de uma força de adesão e estética máximas. Por fim, foi desenvolvido um sistema de fotopolimerização como solução especializada para a cimentação de facetas.

Aqui está uma informação aprofundada sobre cada um dos três sistemas de cimentação PANAVIA™.

Cimento quotidiano

É possível manter a cimentação simples e eficiente minimizando o número de etapas e componentes de trabalho e resolvendo os desafios existentes. O cimento resinoso de dupla polimerização e autoadesivo PANAVIA SA Cement Universal foi concebido para estes fins. O desafio de remover o excesso de cimento pegajoso é ultrapassado graças a uma fórmula que permite que o excesso seja limpo com facilidade.

Os componentes são reduzidos porque o produto incorpora o monómero MDP original da Kuraray Noritake Dental Inc. e o agente de acoplamento de silano, o monómero LCSi original, para uma adesão forte e duradoura. Enquanto o MDP estabelece uma ligação química forte e duradoura com o esmalte, a dentina, o metal e a zircónia, o LCSi é responsável pela adesão à resina composta, às cerâmicas e às cerâmicas à base de sílica (como o dissilicato de lítio), eliminando a necessidade de primários separados.

Isto significa que só é necessário um componente, o que simplifica o procedimento, poupando tempo e reduzindo o potencial de erro. Graças às suas propriedades, o PANAVIA SA Cement Universal é ideal para procedimentos quotidianos, como a cimentação permanente de coroas e pontes feitas de zircónia, dissilicato de lítio, cerâmica híbrida ou mesmo metal.

O cimento mais forte e esteticamente mais agradável da gama

Para aqueles que pretendem a máxima força de ligação e estética, o PANAVIA V5 é a solução. O fiável sistema de cimentação de dupla polimerização, composto por um primário dentário, um cimento em pasta e um primário cerâmico, oferece a mais elevada força de adesão e estética da gama de cimentos PANAVIA.

É uma excelente escolha para toda uma gama de restaurações indirectas e procedimentos de pinos e cotos. Uma vez que os componentes bem alinhados são sempre combinados e aplicados da mesma forma, promove-se a normalização e obtêm-se resultados previsíveis.

O especialista em facetas

Ao realizar tarefas exigentes como a cimentação de facetas, todos os dentistas precisam de tempo. Especialmente quando se colocam várias facetas ao mesmo tempo para obter os melhores resultados estéticos, ter de correr contra o tempo de colocação é contraproducente. Por este motivo, a Kuraray Noritake Dental Inc. desenvolveu o PANAVIA Veneer LC, um sistema de cimento resinoso fotopolimerizável com um tempo de trabalho alargado de 200 segundos*, que lhe permite começar a polimerizar quando estiver pronto para isso.

PANAVIA Veneer LC também oferece uma viscosidade e consistência de pasta bem alinhadas para uma fácil distribuição e colocação, e está disponível em quatro cores altamente estáveis do ponto de vista cromático para uma estética duradoura. Por fim, o sistema garante uma fácil remoção do excesso após a cura e uma excelente força de adesão ao longo do tempo.

** Tempo de trabalho: sensibilidade à luz (8000 lux, ISO 4049)

Satisfazer as expectativas

Os três produtos mencionados são exactamente o que é necessário para satisfazer todas as preferências pessoais e indicações específicas. São baseados na longa experiência da Kuraray Noritake Dental Inc. no desenvolvimento de cimentos de resina adesivos. O primeiro produto da marca PANAVIA foi introduzido na década de 1980 e, desde então, a empresa nunca parou de melhorar o portfólio, combinando tecnologias existentes, como o monómero MDP original, com tecnologias recentemente desenvolvidas, como o monómero LCSi e a tecnologia Touch Cure. Isto conduziu à actual gama de cimentos de resina fáceis de utilizar e altamente estéticos que oferecem um nível muito elevado de força de adesão.

Case by Michal Jaczewski

This patient came to the clinic to improve the aesthetics of her smile. After an aesthetic and functional analysis, it was decided to align and restore the teeth using a minimally invasive protocol with flowable composite.

INITIAL SITUATION

Fig. 1. The patient had worn teeth, visible abrasion, erosion and crowding in the lower arch.

Fig. 2. Situation after orthodontic treatment, full arch ready to restore.

Fig. 3. A silicon mould is used for the Flowable Injection Technique to restore the teeth with flowable composite. The silicone injection mould had injection channels prepared and was placed to check for proper fit.

Fig. 4. For this case it was decided to use CLEARFIL MAJESTY™ ES Flow Low in shade XW.

Fig. 5. Teflon tape was used, in order to separate the teeth.

Fig. 6. The restoration is completely additive; the teeth are not prepared at all. Total etching of the enamel is the best pre-treatment in this situation. K-Etchant Syringe (35% phosphoric acid) was applied for 10 seconds.

Fig. 7. A surgical suction tip was used in order to carefully remove the phosphoric acid gel and protect the isolations on the teeth. Followed by rinsing off completely with water in the usual manner.

Fig. 8. Each tooth was gently air dried for 10 seconds. CLEARFIL™ Universal Bond Quick was applied with a rubbing motion without additional waiting time. Followed by drying of the entire bonding treated surfaces by blowing mild air for more than 5 seconds until the bonding no longer moves.

Fig. 9. Light curing of each bonded tooth for 10 sec.

Fig. 10. The silicon mould is used to inject CLEARFIL MAJESTY™ ES Flow Low (optimal flowability, and properties for a case like this).

Fig. 11. Using the protocol „Treat one, skip one” several teeth are restored simultaneously.

Fig. 12. Situation directly after first round of injections.

Fig. 13. Situation after restoring all teeth, before polishing.

Fig. 14. To create a natural gloss the following polishing protocol was used: 1.) Sof-Lex™* discs, 2.) CLEARFIL™ Twist DIA for Composite polishing wheels, 3.) diamond paste and finally zinc oxide paste.

*Not a brand name of Kuraray Noritake Dental.

Fig. 15. High-shine results after polishing.

FINAL SITUATION

Fig. 16. Final restoration, immediately after treatment.

Fig. 17. Final restoration after 2 days.

Dentist:

MICHAL JACZEWSKI

Michał Jaczewski graduated from Wroclaw Medical University in 2006 and today runs his private practice in the city of Legnica, Poland. He specializes in minimally invasive dentistry and digital dentistry and is the founder of the Biofunctional School of Occlusion. Here he lectures and runs workshops with focus on full comprehensive patient treatments.

O pré-requisito para a cimentação adesiva é uma ligação fiável entre o dente e o material de restauração. A qualidade da união depende do cimento resinoso e da sua correcta aplicação. O estado da superfície de aderência também desempenha um papel decisivo. As superfícies dos dentes e das restaurações devem ser condicionadas e limpas.
Falámos com o Dr. Adham Elsayed.

Como é que a superfície deve ser pré-tratada ou condicionada para a cimentação adesiva?

O pré-tratamento da superfície depende da estrutura ou microestrutura da cerâmica. As cerâmicas de silicato (por exemplo, cerâmicas de vidro) têm uma fase vítrea e podem ser gravadas. O condicionamento aumenta a área da superfície, preparando-a assim para a cimentação adesiva. Em contraste, as cerâmicas à base de óxido, como a zircónia e os compósitos, não têm fase vítrea ou têm uma fase vítrea insignificante. Não podem ser gravados. A sua superfície é condicionada por abrasão a ar (com óxido de alumínio). Este é o único método actualmente comprovado cientificamente para conseguir uma ligação fiável com estes materiais.

Qual a importância de uma limpeza correcta do dente e da superfície da restauração para a qualidade da adesão?

A superfície da restauração deve ser descontaminada imediatamente antes da cimentação. A contaminação deve ser cuidadosamente removida. A lavagem com água ou álcool revelou-se insuficiente. Por conseguinte, foram desenvolvidas soluções de limpeza como o KATANA Cleaner.

Esfregar, enxaguar e secar: alguns passos para procedimentos de colagem óptimos. Ao contrário de outros produtos de limpeza, que têm de ser esfregados durante mais tempo e só são adequados para utilização extra-oral devido ao seu elevado valor de pH, o KATANA Cleaner é aplicado em 10 segundos e é adequado tanto para utilização intra-oral como extra-oral.

Qualquer contaminação é prejudicial para a ligação adesiva. Quando a restauração é testada, por exemplo, a sua superfície fica contaminada. A saliva, eventualmente o sangue, etc. acumulam-se e as proteínas contidas actuam isolando todos os componentes aplicados posteriormente (por exemplo, o iniciador). Por conseguinte, qualquer contaminação deve ser cuidadosamente removida antes do procedimento de colagem. Isto também se aplica às restaurações adesivas directas. O KATANA Cleaner oferece uma forma rápida e fácil de realizar esta tarefa.

O que torna o KATANA Cleaner tão interessante para o utilizador?

As características especiais do KATANA Cleaner são o sal MDP integrado e o valor de pH suave. Vejamos a função do sal MDP. Ao esfregar (durante 10 segundos), o detergente faz com que as partículas contaminantes (por exemplo, resíduos de processos, proteínas da saliva, sangue, etc.) adiram ao sal MDP como um íman. A contaminação é removida da superfície através de uma lavagem com água. Esta capacidade é atribuível ao sal MDP e torna o KATANA Cleaner atractivo e fácil de utilizar. Além disso, o valor do pH permite-nos utilizar a solução de limpeza tanto intra-oral como extra-oral, outra característica especial. Em geral, recomendamos a utilização do KATANA Cleaner para restaurações directas e indirectas. Graças à aplicabilidade universal da solução de limpeza, é necessário apenas um material e o tempo necessário é extremamente reduzido. Ao colar pilares a uma base de titânio, recomenda-se também a limpeza com KATANA Cleaner, uma vez que proporciona uma base ideal (antes da aplicação do primário). Neste caso, a contaminação (por exemplo, gordura dos dedos, resíduos de abrasivos do ar) também pode actuar como isolante e prejudicar a qualidade da ligação.

Referências:

1. Ladha K, Verma M. Conventional and contemporary luting cements: an overview. J Indian Prosthodont Soc. 2010;10(2):79-88.
2. Edelhoff D, Özcan M. To what extent does the longevity of fixed dental prostheses depend on the function of the cement? Working Group 4 materials: cementation. Clin Oral Implants Res. 2007;18 Suppl 3:193-204.
3. Güth JF, Stawarczyk B, Edelhoff D, Liebermann A. Zirconia and its novel compositions: What do clinicians need to know? Quintessence Int. 2019;50(7):512-20.
4. Smith CT, Gary JJ, Conkin JE, Franks HL. Effective taper criterion for the full veneer crown preparation in preclinical prosthodontics. J Prosthodont. 1999;8(3):196-200.
5. Uy JN, Neo JC, Chan SH. The effect of tooth and foundation restoration heights on the load fatigue performance of cast crowns. J Prosthet Dent. 2010;104(5):318-24.

KATANA™ Zirconia STML e PANAVIA™ SA Cement Universal

KATANA™ Zirconia STML é um material muito popular utilizado em muitos laboratórios dentários em todo o mundo. Em comparação com os materiais de estrutura de zircónia convencionais com uma estrutura policristalina predominantemente tetragonal, o KATANA™ Zirconia STML tem um teor de ítria mais elevado, o que leva a uma estrutura de material diferente com um impacto nas propriedades ópticas e físicas (a translucidez aumenta, a resistência à flexão diminui). Consequentemente, o campo de indicações é limitado a restaurações de um único dente e pontes de duas ou três unidades nas regiões anterior e posterior. A maior vantagem reside num potencial estético muito mais elevado, razão pela qual este material é utilizado principalmente para o fabrico de restaurações monolíticas ou com um corte de micro cerâmica individualizado.

Embora as indicações e o procedimento técnico sejam bem conhecidos, parecem existir algumas obscuridades relativamente ao manuseamento no consultório dentário. A cimentação convencional é possível e recomendada ou é preferível um procedimento de cimentação adesiva? O pré-tratamento da superfície é o mesmo que para a zircónia tetragonal ou é necessário um procedimento diferente? E o que se pode esperar relativamente ao comportamento a longo prazo das restaurações de KATANA™ Zirconia STML? Um olhar atento sobre a literatura científica disponível fornece algumas orientações.

Colocação final das restaurações KATANA Zirconia STML

Cimentação convencional ou adesiva? Em princípio, ambos os procedimentos são possíveis quando a restauração a ser colocada tem um desenho retentivo. É geralmente aceite que uma coroa de cobertura total proporciona retenção suficiente para a cimentação convencional quando o pilar dentário tem pelo menos 4 mm de altura e o ângulo de convergência das paredes axiais se situa entre 6 e 12 ou, no máximo, 15 graus.^1,2

A razão é que a resistência à flexão do material é superior a 350 MPa,³ o valor crítico para o endurecimento por cimentação convencional. No entanto, uma vez que os cimentos convencionais são opacos e só estão disponíveis numa cor, a utilização de um cimento de resina (auto-)adesivo pode ser preferível com todos os materiais de restauração altamente translúcidos por razões estéticas. Em todo o caso, estes produtos são obrigatórios quando a preparação macro-retentiva não é possível ou não é desejada. Em resumo, a utilização de um cimento resinoso auto-adesivo ou adesivo é preferível em muitas situações. Um argumento a favor dos cimentos de resina auto-adesivos é o menor esforço envolvido na sua utilização.

Mas o que acontece com o pré-tratamento da zircónia? Independentemente do tipo de zircónia dentária utilizada, o condicionamento com ácido fluorídrico é ineficaz devido à falta de matriz vítrea no material. No entanto, é evidente que a modificação da superfície é necessária para estabelecer uma ligação forte e duradoura com qualquer sistema de cimento resinoso.^4,5

O método geralmente recomendado para a zircónia de alta resistência é o jacto de areia com partículas de óxido de alumínio ou revestimento triboquímico de sílica.⁴ O tamanho da partícula deve ser pequeno (≤ 50 µm) e a pressão baixa (aprox. 1 bar) para evitar um enfraquecimento das propriedades mecânicas do material.^3,4 Para variantes de material de baixa resistência, este risco de enfraquecimento do material parece ser maior,5 pelo que se torna ainda mais importante trabalhar com uma pressão e tamanho de partícula baixos.^5-8 No caso da zircónia KATANA™, no entanto, foi relatado que "o jacto de areia com alumina aumentou significativamente a resistência à flexão biaxial da KATANA STML".⁹ Isto significa que o jacto de areia adequado das restaurações de zircónia KATANA STML não afectou a resistência à flexão do material, que foi até aumentada devido às propriedades específicas da zircónia da Kuraray Noritake Dental.

Com base nestes resultados, são recomendados os seguintes procedimentos para a zircónia de alta translucidez:

Opção 1

Abrasão a ar com óxido de alumínio seguida da utilização de um cimento resinoso auto-adesivo contendo 10-MDP.⁶

Opção 2

Revestimento triboquímico de sílica seguido de silanização da superfície de ligação.⁶

Uma vez que o cimento resinoso auto-adesivo de dupla cura PANAVIA SA Cement Universal contém tanto o monómero MDP original como o agente de acoplamento de silano de cadeia de carbono longa (monómero LCSi), é adequado para ambos os procedimentos.

O PANAVIA SA Cement Universal está disponível numa seringa de mistura automática e num sistema de mistura manual, que consiste numa formulação pasta-pasta. Uma pasta contém o monómero MDP original num ambiente de monómero hidrofílico e a outra contém o monómero LCSi inactivo num ambiente de monómero hidrofóbico. Quando as pastas são extrudidas, são misturadas na ponta de mistura da seringa (automix) ou distribuídas num bloco de mistura e misturadas à mão (handmix). Posteriormente, o material é simplesmente aplicado no entalhe da restauração e a restauração é colocada. A limpeza do excesso de cimento é mais fácil após a cura (2 a 5 segundos).

Funciona bem no ambiente clínico?

A melhor maneira de testar se o procedimento descrito é bem sucedido no ambiente clínico é realizar um estudo clínico. Foi exactamente isto que uma equipa de investigadores da Universidade Complutense de Madrid, Espanha, fez com a combinação dos materiais KATANA Zirconia STML e PANAVIA SA Cement Universal.¹⁰ No estudo clínico prospectivo, foram colocadas 30 coroas posteriores feitas de KATANA Zirconia STML em 24 indivíduos que necessitavam de restaurações de dentes posteriores. Os dentes foram preparados como recomendado para restaurações de cerâmica pura, permitindo uma espessura de parede de aproximadamente 1 mm (espessura mínima recomendada do KATANA Zirconia STML para coroas na região posterior): 1,0 mm). As restaurações foram sinterizadas, caracterizadas e glazeadas de acordo com as recomendações do fabricante do material e posteriormente testadas. Antes da cimentação, o entalhe das restaurações foi pré-tratado com partículas de óxido de alumínio (50 µm, 1 bar de pressão) seguido de limpeza ultra-sónica. A utilização do PANAVIA SA Cement Universal também estava de acordo com as recomendações do fabricante.

A avaliação clínica das coroas foi efectuada após 6, 12 e 24 meses, utilizando o sistema de avaliação da qualidade da California Dental Association (CDA). Os parâmetros avaliados neste sistema são a superfície e a cor das restaurações, a sua forma anatómica e a integridade marginal das coroas. Após 24 meses, as taxas de sucesso e de sobrevivência eram de 100%. Para todos os três parâmetros, as coroas receberam uma classificação "satisfatória" (pontuação 3 ou 4), enquanto a integridade marginal (o parâmetro chave para avaliar o desempenho do cimento resinoso) recebeu uma classificação "excelente" (a pontuação mais elevada possível 4) em todos os 30 casos.

Conclusão

Os investigadores concluíram que "os excelentes resultados obtidos neste estudo sugerem que as coroas de zircónia monolítica de terceira geração suportadas pelo dente nas regiões posteriores parecem ser uma boa alternativa às coroas metalo-cerâmicas, às coroas de zircónia monolítica de segunda geração e às coroas de zircónia folheada. É necessário um estudo a longo prazo para confirmar este estudo a curto prazo". Parece, portanto, que o KATANA Zirconia STML e o PANAVIA SA Cement Universal são uma equipa promissora e que a adesão aos protocolos recomendados pode produzir resultados excelentes e estáveis durante muitos anos.

Fotos: KATANA Zirconia STML NW e CERABIEN ZR FC Paste Stain - Sergio R. Arias DDS, MS Sung Bin Im, MDC, CDT

Referências

1. Edelhoff D, Özcan M. To what extent does the longevity of fixed dental prostheses depend on the function of the cement? Working Group 4 materials: cementation. Clin Oral Implants Res. 2007;18 Suppl 3:193-204.
2. Güth JF, Stawarczyk B, Edelhoff D, Liebermann A. Zirconia and its novel compositions: What do clinicians need to know? Quintessence Int. 2019;50(7):512-20.
3. Kern M, Beuer F, Frankenberger R, Kohal RJ, Kunzelmann KH, Mehl A, Pospiech P, Reis B. All-ceramics at a glance. An introduction to the indications, material selection, preparation and insertion techniques for all-ceramic restorations. Arbeitsgemeinschaft für Keramik in der Zahnheilkunde. 3rd English edition, January 2017.
4. Comino-Garayoa R, Peláez J, Tobar C, Rodríguez V, Suárez MJ. Adhesion to Zirconia: A Systematic Review of Surface Pretreatments and Resin Cements. Materials (Basel). 2021 May 22;14(11):2751.
5. Mehari K, Parke AS, Gallardo FF, Vandewalle KS. Assessing the Effects of Air Abrasion with Aluminum Oxide or Glass Beads to Zirconia on the Bond Strength of Cement. J Contemp Dent Pract. 2020 Jul 1;21(7):713-717.
6. Chen B, Yan Y, Xie H, Meng H, Zhang H, Chen C. Effects of Tribochemical Silica Coating and Alumina-Particle Air Abrasion on 3Y-TZP and 5Y-TZP: Evaluation of Surface Hardness, Roughness, Bonding, and Phase Transformation. J Adhes Dent. 2020;22(4):373-382.
7. Alammar A, Blatz MB. The resin bond to high-translucent zirconia-A systematic review. J Esthet Restor Dent. 2022 Jan;34(1):117-135.
8. Soto-Montero J, Missiato AV, dos Santos Dias CT, Giannini M. Effect of airborne particle abrasion and primer application on the surface wettability and bond strength of resin cements to translucent zirconia. J Adhes Sci Technol, Online publication May 2022.
9. Inokoshi M, Shimizubata M, Nozaki K, Takagaki T, Yoshihara K, Minakuchi S, Vleugels J, Van Meerbeek B, Zhang F. Impact of sandblasting on the flexural strength of highly translucent zirconia. J Mech Behav Biomed Mater. 2021 Mar;115:104268.
10. Gseibat M, Sevilla P, Lopez-Suarez C, Rodríguez V, Peláez J, Suárez MJ. Prospective Clinical Evaluation of Posterior Third-Generation Monolithic Zirconia Crowns Fabricated with Complete Digital Workflow: Two-Year Follow-Up. Materials (Basel). 2022 Jan 17;15(2):672. (https://pubmed.ncbi.nlm.nih.gov/35057389/).

THE COMBINATION OF EFFECT LIQUIDS AND MICRO-LAYERING ON HIGHLY AESTHETIC ZIRCONIA IS THE EFFECTIVE WAY TO ACHIEVE OUTSTANDING RESULTS

Case by Leonidas Dimitriou, MDT

As an addition to its well-aligned portfolio of multi-layered zirconia (KATANA™ Zirconia Multi-Layered series) and veneering porcelain for zirconia (CERABIEN™ ZR), Kuraray Noritake Dental Inc. has recently introduced a set of dyeing liquids. Esthetic Colorant for KATANA™ Zirconia is applied to the surface of the monolithic or anatomically reduced zirconia restoration prior to the final sintering procedure. In this way, it is possible to imitate typical internal colour effects of natural teeth quite easily. Depending on the desired outcome, users may add just a final layer of glaze, liquid ceramics or stains and porcelains to their zirconia restorations treated with Esthetic Colorant. The following two case examples are used to demonstrate two different procedures involving the use of the effect liquids.

CASE EXAMPLE 1

In the first case, we produced three two-unit splinted crown restorations for six maxillary anterior teeth. The zirconia crowns (made of KATANA™ Zirconia YML) were anatomically reduced and individualized with Esthetic Colorant mainly in the incisal and cervical areas immediately after milling. For the application of the selected liquids, we used the Liquid Brush Pen specifically developed for Esthetic Colorant. The restorations were dried for half an hour, placed in the sintering furnace for sintering according to the recommended protocol for KATANA™ Zirconia and subsequently finished with CERABIEN™ ZR porcelains. Finally, CERABIEN™ ZR Paste Stain Glaze was applied for the final high-gloss finish.

Fig. 1. Pre-sintered anatomically reduced crowns after milling.

Fig. 2. Esthetic Colorant applied to the milled restorations.

Fig. 3. Appearance of the individualized restorations after the final sintering procedure.

Fig. 4. Restorations after porcelain layering.

FINAL SITUATION

Fig. 5. Final restorations with a natural appearance. The effects created with Esthetic Colorant shine from deep within the restorations.

Fig. 6. Lateral view of the final restorations from the left.

Fig. 7. Lateral view of the final restorations from the right.

CASE EXAMPLE 2

In this second case, two three-unit restorations were produced using KATANA™ Zirconia YML in the colour A3. We designed and milled them in full contour, then reduced them with hand instruments by 0.2 mm and added some texture effects to the surface before applying Esthetic Colorant. In this case, we played with different shades of Esthetic Colorant. Even when applied on a minimally reduced or monolithic surface, the liquids are able to create a nice depth effect as they diffuse into the zirconia structure. The amount of liquid applied is easily controlled with the Liquid Brush Pen, so that the intensity of the colours is predictable. After sintering, we added some internal stains, CERABIEN™ ZR Luster Porcelain and a final layer of CERABIEN™ ZR FC Paste Stain Glaze to finish the restorations. The outcome speaks for itself.

Fig. 8. Milled monolithic restorations with a pronounced surface texture.

Fig. 9. Vestibular and palatal surfaces individualized with Esthetic Colorant to create and intensify some natural colour effects.

Fig. 10. Appearance of the restorations immediately after sintering.

Fig. 11. Restorations after internal staining.

Fig. 12. A layer of luster porcelain applied to the minimally reduced restorations.

FINAL SITUATION

Fig. 13. Final outcome after glazing.

Dentist:

LEONIDAS DIMITRIOU, MDT

Interview with Yoshihisa Yamada
General Manager, Technology Division of Kuraray Noritake Dental Inc.

KATANA™ Zirconia ML was introduced ten years ago, at the IDS 2013 in Cologne, as the dental industry’s first zirconia product with a multi-layered colour structure. Since that event, KATANA™ Zirconia ML blanks have become very popular. Continued development efforts have led to the current line-up of multi-layered materials, KATANA™ Zirconia UTML, STML and HTML PLUS, and our latest product – KATANA™ Zirconia YML. Our new technology with colour, translucency and strength gradation is found in KATANA™ Zirconia YML.

Photo credits to MDT Giuliano Moustakis.

How important was the invention of the Kuraray Noritake Dental’s original multi-layered technology for the dental market?

Our impression is that the material has had a significant impact on the dental market. Being the first zirconia material with a multi-layered colour structure, KATANA™ Zirconia ML was our first product of its class to offer the properties needed for the efficient production of full-contour zirconia restorations with a natural look. Before its introduction, the “full-contour zirconia” concept had not been widely accepted due to the aesthetic properties of the zirconia materials available so far: Many of them lacked the desired level of translucency, while others needed to be treated with dyeing liquids or stains in a complex procedure to obtain a natural shade appearance. With the launch of multi-layered zirconia blanks, which successfully added natural colour gradation to the structure, aesthetic full-contour zirconia restorations started to become popular among dental technicians worldwide. The high potential of the technology was confirmed at the IDS 2013 show, when we saw not only end-users, but also engineers from competing companies come to look at this product.

4-layer colour structure of KATANA™ multi-layered discs.

Photo credits to MDT Daniele Rondoni.

What changes were driven forward by the introduction of KATANA™ Zirconia ML?

After the introduction of KATANA™ Zirconia ML, many companies started developing multi-layered zirconia discs, creating a new dental product category with an added technical and clinical value. We are convinced that the invention of Kuraray Noritake Dental has played a major role in the shift from zirconia exclusively used as a framework material to alternative approaches including full-contour zirconia restorations. If only monochromatic zirconia discs had been available, we imagine that an increased number of dental technicians would have embraced the concept of using liquid colourants to achieve a natural appearance of full-contour crowns and bridges. That would have prevented monolithic zirconia restorations from becoming as popular as they are today.

How did the KATANA™ Zirconia ML technology evolve over the past ten years?

Based on our unique core technology developed for inventing KATANA™ Zirconia ML, we have been continuing making efforts to create even better products. One of Kuraray Noritake Dental’s great strengths is its ability to develop all the raw materials for its zirconia products inhouse. This makes it possible for us to adjust the boundaries between the layers as inconspicuously as possible, even when discs consist of multiple layers. This enabled us to provide multi-layered discs with the required strength and aesthetic qualities, and with a stable, predictable shrinkage rate. In the past ten years, we have focused on adding new materials with different levels of translucency and strength to offer a portfolio that meets the demands of virtually every dental technician, practitioner and patient.

For example, the advent of KATANA™ Zirconia STML, which has even better aesthetic qualities than KATANA™ Zirconia ML, has made it possible to use it all by itself to create highly aesthetic restorations, with no need to characterize or individualize the restorations. Of course, if you use KATANA™ Zirconia Multi-Layered discs and treat the restorations with a surface staining agent, such as CERABIEN™ ZR FC Paste Stain, you can create even more aesthetic restorations in a shorter time.

What are the benefits of Kuraray Noritake Dental’s multi-layered technology, as compared with other manufacturer’s solutions?

KATANA™ Zirconia multi-layered discs offer the advantage of delivering the proper colour even when they are sintered at high speed. There are two reasons for this. First, we developed unique raw materials with suitable characteristics for high-speed firing. This allows the creation of restorations with the same strength, stability, and aesthetics to be achieved after both short- and long-time firing. The second reason is that we possess the technical know-how concerning excellent shading that Noritake Dental Supply, one of Kuraray Noritake Dental’s predecessors, cultivated during its many years spent developing ceramic materials. Noritake Co., Ltd., parent company of Noritake Dental Supply, is a long-established ceramic manufacturer that is famous for its tableware and other outstanding products. It is this background that allows us to properly control pigment coloration using our inorganic pigment know-how and to provide unique firing schedules. These two strengths enable us to bring unique advantages to our products. That is, they remain stable and retain appropriate colouration even under rapid firing schedules.

CERABIEN™ ZR FC Paste Stain being applied to KATANA™ Zirconia restoration.

Photo credits to MDT Roberto Rossi.

How did you manage to shorten the sintering times so significantly, resulting in your speedy sintering with uniform protocols?

When shorter sintering times became possible, Kuraray Noritake Dental recommended that KATANA™ Zirconia ML be sintered for seven hours. After that, when a new furnace claiming being capable of short-time firing was launched, we used it to fire KATANA™ Zirconia ML on a trial basis. We found, happily, that our zirconia material was uniquely compatible with rapid firing. This was the beginning of our full-fledged study of short-time firing of our zirconia material. You could say that we began investigating short-time firing almost by accident. Then, while developing KATANA™ Zirconia STML and KATANA™ Zirconia UTML, successors of KATANA™ Zirconia ML, we focused on incorporating short-time firing into their features and made various adjustments, finally achieving the optimal combination of factors for the successful short-time firing of zirconia.

What are the benefits of Kuraray Noritake Dental’s second-generation multi-layered technology, as compared with other manufacturer’s solutions?

One advantage of KATANA™ Zirconia YML is that it can be applied to treat a wider range of cases without complex limitations on position within the disc. The reason: it delivers this high level of aesthetics while still maintaining great strength. This advantage of being appropriate for a wider range of cases also simplifies inventory management. In addition, users benefit from our expertise in developing raw materials and reproducing colour with ceramics. This expertise enabled us to develop a zirconia product in which each layer has a different level of translucency, while great strength and admirable aesthetics are maintained throughout the whole blank.

The sintering recommendation is only a guideline; some adjustments may be required depending on each individual furnace. If the furnace cannot be set according to the 54- or 90-minute sintering schedule, speed sintering cannot be used.

* The restorations may be removed at 800°C or less depending on the circumstances.
** For the sintering schedule of KATANA™ Zirconia HT, please refer to the Handy Chart in product packaging.

Is it really possible to address every case using only KATANA™ Zirconia YML?

For every case that can be treated either with KATANA™ Zirconia STML, KATANA™ Zirconia UTML, or KATANA™ Zirconia HTML PLUS, KATANA™ Zirconia YML is also an option. Hence, it is possible to use only KATANA™ Zirconia YML for all your zirconia cases – which is probably one of the reasons for its great popularity. It features both great strength and excellent aesthetics, and – being so versatile – it helps simplify inventory management. Of course, Kuraray Noritake Dental’s other multi-layered materials feature outstanding properties as well. Depending on the features you need, it would also be an option to select from these products - KATANA™ Zirconia STML, KATANA™ Zirconia UTML, or KATANA™ Zirconia HTML PLUS – to realize your ideal restorations.

KATANA™ Zirconia YML, finished with CERABIEN™ ZR.

Photo credits to MDT Giuliano Moustakis.

Why is the KATANA™ brand in general so popular among dental technicians around the world?

We think that dental technicians choose KATANA™ because they find that they can create highly aesthetic restorations using simple, straightforward steps.

Is there any further development potential in multi-layered technology?

On the basis of our technical know-how, there is always room for improvement. That is why we never stop innovating and listening to the voice of our customers. Developing what supports them in improving their outcomes while providing for more predictable, less stressful procedures is our ultimate goal. Right now, we expect to develop products with even greater strength, increased translucency, and outstanding aesthetics that will have a natural look resembling real teeth, even when the material used is full-contour zirconia.

Dentist:

YOSHIHISA YAMADA

We are thrilled to share with you our latest brochure – KATANA Zirconia Restoration System, featuring Kuraray Noritake Dental Inc’s product line-up that is dedicated to creating true-to-live restorations.

The KATANA Zirconia Family brochure features a range of lab-side products that are designed to meet the needs of modern dental professionals.

Our zirconia materials offer excellent strength and aesthetics, making them a top choice for prosthetic dentistry. In the new KATANA Zirconia Family brochure, you can read detailed information, key technical parameters, and suggested indication ranges for all our zirconia products - KATANA Zirconia UTML, STML, HTML PLUS, YML and HT. Also, we look at other products from our range such as CERABIEN ZR Porcelain, FC Paste Stain and  Esthetic Colorant that are and excellent choice for characterization of zirconia restorations, provide an overview of the sintering programs of KATANA Zirconia multi-layered discs and offer useful tips and tricks on how to best handle our zirconia.

With the KATANA Zirconia Family brochure, you will have all the basic information you need to make informed decisions about materials suitable for your dental lab.

Have a read, learn more and stay up to date!

Case by CDT Daniele Rondoni and MDT Roberto Rossi

Working with high-translucency, multi layered zirconia (KATANA™ Zirconia Multi-Layered series from Kuraray Noritake Dental Inc.) paves the way toward indirect restorations that are closely adapted to our patients’ needs. Reduced wall thicknesses allow for minimally invasive tooth preparations, while polished zirconia in the occlusal contact areas provides for an antagonist-friendly behaviour. All this is possible due to the high aesthetic potential and homogeneous structure of the materials, which work well with a full-contour design or slight vestibular cutback. For individualization or characterization, different options are available. The portfolio of finishing solutions from Kuraray Noritake Dental has just been complemented by Esthetic Colorant for KATANA™ Zirconia, a set of twelve dyeing liquids for the company’s multilayered zirconia. They are applied to the milled restoration surface prior to sintering.

Some readers may wonder why there is a need for effect liquids applied to pre-shaded zirconia with a multi-layered colour structure. Being aware of natural teeth’s unique play of colours stemming from the shape and shade of the dentin core, however, the reason is quite obvious: Esthetic Colorant diffuses into the zirconia structure, hence allowing us to create depth effects even in monolithic restorations. Moreover, it enables the user to pre-treat tissue areas, and even by using the liquids on cutback designs, we are able to reproduce case-specific internal optical characteristics quite easily. Our standard approach for the use of Esthetic Colorant on KATANA™ Zirconia HTML Plus is described by means of the following case example: An implant- and tooth-based twelve-unit bridge with a slight vestibular cutback design, finished with Esthetic Colorant and CERABIEN™ ZR Porcelain.

Fig. 1. Restoration with sintering support removed from the blank.

Fig. 2. Esthetic Colorant for KATANA™ Zirconia: Available shades.

Fig. 3. Frontal view of the milled restoration after the application of Esthetic Colorant. A chromatic map is not needed since the colours of the applied liquids are clearly visible.

Fig. 4. Occlusal view of the milled restoration after the application of Esthetic Colorant. The liquids were applied with the Liquid Brush Pen for Esthetic Colorant.

Fig. 5. Frontal view: Appearance of the restoration after sintering.

Fig. 6. Occlusal view: Appearance of the restoration after sintering.

Fig. 7. Beautiful translucency and mamelon structures in the incisal area.

Fig. 8. Situation after the application of a thin layer of CERABIEN™ ZR Porcelain, which creates an enamellike window effect and reveals the play of colours found underneath.

Fig. 9. Restoration after firing and glazing.

FINAL SITUATION

Fig. 10. Beauty shots…

Fig. 11. … of the final restoration.

Easy handling and application, impressive colour effects: Esthetic Colorant perfectly fits into our micro-layering approach with a cutback design adjusted to the age and needs of every patient. Being applied on the pre-sintered zirconia surface, the liquids do not require any extra heat treatment – the restoration is simply dried and then sintered as usual. Esthetic Colorant may be used instead of or in combination with internal stains, luster porcelains and liquid ceramics – whatever complements a laboratory’s existing approach to highly aesthetic zirconia restorations.

Dentists:

Case by Kokla Thalia, Postgraduate student in Restorative Dentistry program, Faculty of Dentistry, National and Kapodistrian University of Athens, Greece

Restoring Class II cavities can be challenging due to limited access to the posterior area, where the interproximal contact needs to re-established in a proper way. Inadequate contacts tend to result in increased plaque accumulation, food impaction and, as a consequence, the development of caries and irritation of the interproximal gingiva. Therefore, it is essential that the interproximal contact is restored based on the model of nature. A suitable matrix system and a proper clinical protocol can help us succeed in this context. The following clinical case is used to illustrate a possible strategy.

Fig. 1. Initial clinical situation. 23-year-old female patient with caries on the mandibular left second premolar.

Fig. 2. Situation after cavity preparation, isolation of the working field with rubber dam and the placement of a sectional matrix fixed with a ring. It is essential that the matrix imitates the natural shape of the contact area, which is usually rather flat or concave cervically and convex in the middle and occlusal parts.

Fig. 3. Etching of the tooth structure with phosphoric acid etchant. Afterwards, the adhesive needs to be applied (in this case, Universal Bond Quick was used according to the manufacturer’s instructions).

Fig. 4. CLEARFIL MAJESTY™ ES-2 Premium in the shade A3E is applied in the distal box to build up the wall first. In this way, the available space is used to model the most critical part of the restoration before simply filling the cavity in increments with the dentin shade A3D.

FINAL SITUATION

Fig. 5. Final restoration after finishing and polishing. In accordance with the concept behind CLEARFIL MAJESTY™ ES-2 Premium with its pre-defined shade combinations, the final enamel layer was build-up using the shade A3E. However, the use of a single opacity is also possible in the posterior region depending on the aesthetic demands.

CONCLUSION

By elevating deep interproximal margins, it is possible to focus on the critical designing of the contact point when there is still sufficient space available to do so. This simplifies the procedure, while all that is left to do can be managed in a straightforward way like a Class I restoration.