KURARAY NORITAKE PRESENTS
MASTERING ANTERIOR AND POSTERIOR ESTHETICS WITH COMPOSITE
- Gaetano Paolone & Salvatore Scolavino -

Op vrijdag 30 september en zaterdag 1 oktober organiseert Kuraray Noritake een nieuwe editie van Mastering Esthetics in Van der Valk Hotel Amsterdam-Amstel. Onder leiding van de Italiaanse meesters dr. Gaetano Paolone en dr. Salvatore Scolavino wordt er in lezingen, een live-demo en een hands-on masterclass ingegaan op het bereiken van natuurgetrouwe composietrestauraties, zowel anterieur als posterieur.

Op vrijdag presenteren de Italiaanse meesters hun planning en behandeltechnieken in enkele lezingen. Hun doel: kunst en schoonheid bereiken zonder vorm en functie uit het oog te verliezen. Ze geven tips, tricks, do’s en don’ts over de toepassing en verwerking van composiet. Er komen vragen aan bod als: hoe voorkom je dat een composietrestauratie te grijs oogt, wat zijn de mogelijkheden van een universeel composiet, wanneer kies je voor layeren en hoe kun je contactpunten optimaliseren. Een live demo sluit de lezingen af. 

Op zaterdag maakt u de besproken technieken vervolgens eigen in de hands-on masterclass. Na een korte uitleg door Paolone en Scolavino werkt u op model onder hun begeleiding. U werkt met composieten uit de CLEARFIL MAJESTY™-familie. Er is keuze uit een ochtend- of middagprogramma. De maximale groepsgrootte is 20 deelnemers per masterclass.

Gaetano Paolone en Salvatore Scolavino zijn befaamde sprekers op het gebied van anterieure en posterieure directe restauraties. Ze zijn beide lid van de Italiaanse Academie voor Restauratieve Tandheelkunde en de Italiaanse Academie voor Esthetische Tandheelkunde. Ze spraken eerder al op de succesvolle laatste editie van Kuraray’s Mastering Esthetics in 2018. De lezingen zijn in het Engels.

What is the story behind the development of Clearfil Universal Bond Quick Flip-Top Cap?

With this video, we will walk you through the story behind its development.

Users of dental zirconia are really spoilt for choice these days. Countless manufacturers offer zirconia materials that differ in their mechanical and optical properties and indication range. What is not apparent at first sight is that the available products also differ with respect to the quality of the CAD/CAM blanks offered. Blank quality is highly dependent on the quality of the raw materials and is affected by different aspects during raw material processing, pressing and pre-sintering. This has a huge impact on the surface quality, edge stability, fit and processing requirements of milled restorations.

Raw material production

Pre-shaded dental zirconia typically consists of metal oxides, including zirconium oxide, yttrium oxide and aluminium oxide, as well as additives like binders and colour pigments or ions. Most manufacturers of dental zirconia obtain pre-fabricated powder from an external industry partner, the most popular option being Tosoh Corporation. In contrast, Kuraray Noritake Dental relies on an end-to-end in-house process. This includes the production and addition of the components forming the company’s innovative multilayer technology for a polychromatic blank structure and – in the case of "KATANA™ Zirconia" YML – additional translucency and flexural strength gradation.

At Kuraray Noritake Dental, the powder is produced in-house.

Since more powder production steps are carried out in-house, the company is given full control over the quality of the raw materials, their grain size and the purity of the formulation. It also allows for a precise alignment of the mechanical and optical product properties to achieve a smooth transition from one layer to the next. The result is a seamless colour structure and outstanding match of the shades in the polychromatic blanks to the colours of the VITA classical A1–D4 shade guide.

In those materials combining different yttria concentrations in a single blank, additional in-house alignment measures may be taken. In the case of "KATANA™ Zirconia" YML, a completely new raw material was developed to deliver a uniform shrinkage ratio and harmonized coefficients of thermal expansion across the blank und thus bring flexural strength gradation to perfection.

Properties of zirconia restorations that are affected by the powder quality and composition include translucency and shade appearance, flexural strength, ageing behaviour and sintering performance.

Blank pressing

Zirconia discs and blocks used for CAD/CAM processing are usually produced by uniaxial and isostatic pressing. In the uniaxial compaction process, pressure is applied to the powder from one direction (uniaxial) or two directions (biaxial), whereas the isostatic compaction process involves virtually equal pressure applied from all sides. Hence, isostatic pressing typically results in a more uniform density distribution throughout the blank and a higher material homogeneity. These factors are prerequisites for a predictable processing and sintering behaviour and affect the fit of the final restoration. For optimal mechanical and optical properties of the zirconia material, it is essential to avoid large porosities, air pockets and impurities caused by airborne particles that are trapped during pressing.

At Kuraray Noritake Dental, a unique and extremely meticulous pressing process achieves a uniform pressure distribution and low risk of contamination by airborne particles. This specific procedure reduces gravitation forces and contributes to having as high as possible density of zirconia material. All the high-level preparation processes from raw material production to pressing are responsible for the high edge stability and surface quality of restorations milled from "KATANA™ Zirconia".”

Pre-sintering

The pre-sintering procedure is necessary in that it gives the pressed blanks the required stability to be machinable with milling tools. The selected temperature profile and duration of the pre-sintering cycle determine the material’s strength and processing properties and have an impact on the final sintering process.

The unique pre-sintering procedure carried out in the production facilities of Kuraray Noritake Dental results in blanks that are stable in their pre-sintered state. Although more stable, pre-sintered "KATANA™ Zirconia" is machinable with common diamond-coated milling tools without any increased risk of breakage or higher tool wear.

Fast sintering for the laboratory

The unique procedure has a positive impact on the surface smoothness after milling and can significantly shorten sintering times. In the dental laboratory, the sintering times may be reduced to 54 minutes* for single-tooth restorations and bridges of up to three units – an interesting option for rush cases and remakes.

*The material is removed from the furnace at 800 °C.

“KATANA™ Zirconia” YML speed sintered (90-minute sintering schedule), whereas the discs of competitors were sintered using typical overnight sintering schedules suitable for the particular material. Even with 90-minute sintering, KATANA™ Zirconia YML displays superior optical properties when compared to major competitors.

Uniform sintering schedules are offered for the whole "KATANA™ Zirconia" Multi-Layered Series.

Overview of the recommended sintering protocols.

Fast sintering for chairside

Using the "KATANA™ Zirconia" block with Dentsply Sirona’s CEREC system, it is possible to sinter single crowns up to three-unit bridges in 18–30 minutes without compromising the mechanical or optical properties.

The “KATANA™ Zirconia” block displays superior optical properties after 18 minutes of sintering compared with representatives of major competitors’ raw material after 30-minute and 60-minute sintering programs designed by Kuraray Noritake Dental based on the manufacturer’s recommendations.

Unique “KATANA™ Zirconia” properties

Together, these efforts taken by Kuraray Noritake Dental to produce dental zirconia of high quality make all the difference. The "KATANA™ Zirconia" series— "KATANA™ Zirconia" Yttria Multi Layered (YML), Ultra Translucent Multi Layered (UTML), Super Translucent Multi Layered (STML), High Translucent Multi Layered Plus (HTML Plus) and KATANA™ Zirconia High Translucent Mono Layered (HT)—have a homogeneous, high-density structure with low porosity and a high level of purity. In addition, "KATANA™ Zirconia" YML offers a seamless structure without transition lines despite flexural strength gradation. All these properties optimise the performance of the blanks during machining.

SEM images of non-polished “KATANA™ Zirconia” and a competitor’s material at 33× magnification. The four images of each material show the surface structure at different areas of a molar crown. In all areas, the surface of the restoration made of the competitor’s material is rougher and shows more porosity than the surface of the “KATANA™ Zirconia” crown directly after milling, according to Dr Josef Kunkela’s research results. One of the contributing factors to this result is the more densely pressed blanks with smaller grain sizes of “KATANA™ Zirconia”. (Courtesy of Kunkela Research Academy by Dr Josef Kunkela).

Surface roughness

An optimised processing behaviour leads to regular restoration margins, smooth surfaces and a precise fit of the restorations. The latter is due to the fact that the milling behaviour and volumetric shrinkage during final sintering are highly predictable, so that a user designing a 20 μm cement gap will get what he or she desires. Owing to the great control over optical properties and outstanding match to the VITA classical A1–D4 shades, "KATANA™ Zirconia" is considered to be one of the most aesthetic dental zirconia options available on the market.

Exellent marginal fit

SEM images revealing the fit of restorations made of two different materials (lithium disilicate and “KATANA™ Zirconia” Block STML) on a tooth abutment. The “KATANA™ Zirconia” restoration shows a more regular margin and more precise fit (with a cement gap of 19–21 μm) than the lithium disilicate crown (cement gap 26–45 μm). (Courtesy of Kunkela Research Academy by Dr Josef Kunkela).

Extremely regular margins of a “KATANA™ Zirconia” crown after milling, which is also a result of the favourable material structure.

In order to ensure all the desired material properties, including aesthetics and strength, one thing is essential: the machining carried out in the dental laboratory – milling and sintering - needs to adhere to the recommended protocols. This means that the milling machine and furnace should be cleaned and calibrated on a regular basis, which provides the conditions for optimised zirconia processing from the powder to the final, true-to-life dental restoration.

Mathias Fernandez Y Lombardi

EU Scientific Manager
Dental Ceramics & CAD/CAM Materials
Kuraray Europe GmbH

2013
Successful completion of an apprenticeship as a dental technician at Seuthe dental laboratory in Plettenberg, Germany

2018
Successful completion of dental technology studies at the University of Osnabrück, Germany. Graduation as an engineer in dental technology

Since March 2018
Employee of Kuraray Europe GmbH

Simply Create the Panavia Smile

One predictable procedure for cementing your prosthetics reimagined. All your cementation appointments become a joy. Even if you need to cement precious veneers. It’s now possible thanks to the revolutionary PANAVIA™ V5.

This PANAVIA™ V5 video demonstrates the work flow for: 

- Laminate Veneer Cementation

Compact, time-saving and aesthetic

How many different shades of composite do you need to create appealing restorations in virtually every clinical situation? If you opt for “CLEARFIL MAJESTY™ ES-2” Universal shade concept, a few shades will do the trick.

With wonderful support of our internationally recognized key opinion leaders, we have prepared a Clinical Case brochure of “CLEARFIL MAJESTY™ ES-2” Universal for you. The brochure highlights a variety of clinical cases in the anterior and posterior region to show the all about excellent properties of our latest composite. Let the pictures speak for themselves!

Click here to view. Enjoy!

Start Reading: Special MAJESTY ES-2 Universal - Clinical Cases Brochure

By MDT Daniele Rondoni.

This clinical report reveals why you should start:

• using fewer ceramic elements
• choosing minimal ceramic layering
• opting for micro-cutback solutions

without missing the quality and value of your restorations.

Advances in materials development and computer-aided processing allow for more streamlined workflows and an improved collaboration between the dental office and laboratory. In order to benefit from the new options, however, it is important that dental technicians embrace their new responsibilities: they need to keep track of the latest changes and need to acquire profound knowledge of how to leverage the materials’ and technologies’ full potential. Being open for new approaches and restoration techniques is part of this game. In return for their efforts, they will be able to achieve unparalleled aesthetic accuracy in a more efficient procedure.

The evolution of dental zirconia is an excellent example for advances in the field of dental materials: many modern zirconia discs have multi-layered structures and natural tranlucencies. Offering top-level performance and high versatility, these variants are increasingly often the materials of choice for the production of high-quality restorations.

The "KATANA™ Zirconia" multi-layered series, for example, is composed of four multi-layered materials: "KATANA™ Zirconia" HTML PLUS with the highest flexural strength (1,150 MPa) and lowest translucency, "KATANA™ Zirconia" STML with medium strength (748 MPa) and a high translucency, and "KATANA™ Zirconia" UTML with a strength above the level of glass ceramics (557 MPa) and ultra-high translucency. The latest add-on in “KATANA™ Zirconia” portfolio is YML - multi-layered zirconia disc that offers both flexural-strength and translucency gradation. With this portfolio, it is possible to select the right material for every specific need (e.g., high-strength variant for multi-unit restorations, high-translucency variant for anterior crowns). Using the zirconia with a monolithic or minimal vestibular cut-back design and a small layer of porcelain enables us to reduce the wall thickness of the restorations (as compared to a traditional framework design and full porcelain layer). As a consequence, a less invasive tooth preparation is required.

In addition, the design meets the functional needs in terms of low abrasiveness and high toughness, while a sophisticated aesthetic outcome is achieved using micro-layering with the materials contained in the 4.4.1. kit. These can be a winning alternative to traditional ceramic multi-layer solutions, as revealed using the following case example that illustrates the use of the 4.1. technique.

Fig. 1. Digital impression.

Fig. 2. Digital impression taken with the temporary in place.

Fig. 3. Digital model of the prepared teeth imported into the CAD software.

Fig. 4. Digital model of the teeth with temporary imported into the CAD software.

Fig. 5. Designing of four zirconia crowns: Transparent view.

Fig. 6. Designing of four vestibular enamel cutback zirconia crowns.

Dentin structure with internal anatomy

In the present case, "KATANA™ Zirconia" STML, in the shade A2, was selected based on the desired appearance of the final restorations, the colour of the abutment teeth and the space available. The selected design was a minimal vestibular cutback, while the palatal zirconia was left untouched. To replicate the natural aesthetics, we opted for vestibular micro-layering with single luster porcelain and specific internal design of the mamelons.

In order to achieve the best possible aesthetics, it is fundamental to incorporate the internal anatomy into the pre-sintered vestibular surface, and to precisely follow the recommended sintering protocol. Only a flawless sintering procedure will lead to the ideal translucency and correct shade appearance. Following sintering, the surface should be treated with a sandblasting unit (aluminium oxide, particle size 50 μm, pressure 1 to 2 bar).

Fig. 7. Cross-sectional view for a check of the correct thickness.

Fig. 8. Crown made of "KATANA™ Zirconia" STML after sintering.

Fig. 9. Checking the fit of the crowns on the printed working model.

Fig. 10. ILS technique: colour map.

Fig. 11. Application of "CERABIEN™ ZR" Internal Stains.

INTERNAL STAIN ADVANTAGES

• Powder becomes gel and is always ready for use
• The real colours are revealed already before baking
• Optical effects are achieved simply and rapidly
• Excellent adhesion to zirconia is ensured

To improve the mimicry effect, we use the internal light stain technique on the zirconia surface. Incisal Blue one is applied around the mamelons, Mamelon Orange 2 directly on the mamelons for a natural effect. For a calibrated chromaticity, A+ may be added in the cervical area.

Fig. 12. Appearance of the internal stains on the surface after firing.

Fig. 13. Light dynamics after firing.

Fig. 14. Luster layer: Colour map.

Fig. 15. "CERABIEN™ ZR" Luster Porcelain LT1 applied in a micro layer.

Fig. 16. Layering with LT1.

The vestibular body and incisal morphology are completed by adding a single ceramic micro layer of CZR Luster Porcelain LT1.

Before finalizing the restorations, the zirconia surface and texture were optimized with a stone and rubber polishers.

Polishing of the palatal surface was accomplished with Pearl Surface Z diamond paste before a final self-glaze step in the furnace.

Fig. 17. Appearance of the minimal ceramic layer after a single firing procedure.

Fig. 18. Light dynamics after firing.

Fig. 19. Final crowns after mechanical polishing.

Fig. 20. Check on the elements will be carried out on the printed digital model.

Fig. 21. Final situation after cementation.

Fig. 22. Palatal view of the final situation.

Conclusion

Considering aesthetic requirements and case difficulty, today it is possible to adopt different 4.4.1. approaches. In combination with the present generation of multi-layered zirconia, they allow the modern technician to make the best use of digital means to solve complex cases in an easy, effective, and successful manner.

The 4.4.1. system is recommended because it is a selection of materials used in a number of combinations, which help us achieve aesthetically sophisticated outcomes in a feasible, flexible and repeatable way.

For more information about the 4.4.1. system, click here.

Dentist:

DANIELE RONDONI, MDT

• Graduating in 1979, Daniele Rondoni opened a laboratory in 1982, which is also the home of the AAT Community College he founded.
• Teacher and counsellor for the “Italian School for Dental Technicians”at the University of Chieti, University of Sienna and University of Rome Tor Vergata.
• EAED and IAED Active Member and a SICED Associate and O.L.
• International Instructor for Kuraray Noritake Dental products.
• Author of “Tecnica della Multistratificazione in ceramica” (Ceramic Multilayering Technique) and a lab manual about the use of composite materials, introducing his own method – the “Inverted Hardness Layering System”.

Article by Dr. Stefano Daniele.

During bonding procedures for metal-free fixed dental prostheses (FDPs), try-in with specific cement shade matching glycerine paste is necessary for choosing the correct shade of resin-based cement. During try-in, however, saliva and blood could contaminate the bonding surfaces of the ceramic and dental hard tissue. It is essential for the ceramic surface and dental hard-tissue surface to be perfectly clean of bacterial biofilm and other contaminants before adhesive application. Both the procedures ensure efficient bonding and long-term reliability of the adhesive fixed prosthetic intervention.

It is essential for the ceramic surface and dental hard-tissue surface to be perfectly clean.

Cleaning the ceramic bonding surface after try-in

Try-in of metal-free fixed dental prostheses (FDPs) is a key procedure for evaluating the fit of the finishing line of the dental preparation and, for very thin veneers, for matching the resin-based cement to be used to bond the ceramic restorations to the dental hard tissue. Aesthetic features—value in particular—of thin veneers depend on different factors, and one of the most important is the choice of shade of the resin-based cement used under the thin ceramic. To make this procedure easier and repeatable, many manufacturers provide glycerine pastes that have the same colours as those of the corresponding resin-based cements. This pre-bonding procedure of try-in of metal-free FDPs enables the selection of the most appropriate resin-based cement. Glycerine pastes are generally hydrophilic and can be rinsed from the ceramic bonding surface after try-in with an air–water spray, but some contaminants, such as saliva, blood and crevicular fluid, may remain on the surface, and this may affect the efficacy of the bond to the dental hard tissue. Sandblasting contaminated surfaces of metal-free FDPs may be the best choice for removing contaminants from bonding surfaces, but it is important to consider that not all dentists have sandblasting devices in their offices. To this end, Kuraray Noritake Dental launched KATANA™ Cleaner, a specific detergent for decontaminating the bonding surfaces of ceramics that is able to provide complete removal of contaminants from the bonding surfaces of metal-free FDPs after the try-in procedure. A perfectly clean ceramic bonding surface is important for obtaining an effective micromechanical interlocking between glass-ceramic and cement, as well as for allowing the chemical bond reaction between a 10-MDP-based primer and the zirconia bonding surface.

A perfectly clean ceramic bonding surface is important for obtaining an effective micromechanical interlocking between glass-ceramic and cement.

Cleaning the dental hard-tissue bonding surface when sandblasting is not recommended

The dental hard-tissue bonding surface must be clean before bonding metal-free FDPs, and this procedures can be done by sandblasting with a ‘soft’ powder such as erythritol. The focus of this procedure would not be to create an additive retention rate for the ceramic surface, but instead to remove the bacterial biofilm from the dental hard-tissue surface before bonding. Actually, metal-free FDPs are designed to have supra gingival finishing lines. Supra gingival preparation is also important for permitting perfect isolation with a rubber dam. In clinical practice, often the finishing line may be (partly) sub gingival for specific reasons, for example in veneer preparation designed to close diastemas and cervical black triangles between anterior teeth. In those clinical cases, dental dam application may be difficult, and sandblasting dental hard tissue may pose too high a risk of periodontal tissue bleeding. Tissue bleeding near the cervical margin of the preparation before adhesive bonding procedures for metal-free FDPs may affect the seal between the restorative and preparation. These clinical situations indicate the use of cleaning agents rather than sandblasting to clean surfaces before bonding.

Limitations of conventional agents used to clean bonding surfaces

Most conventional cleaning agents are not effective cleaners of ceramic, including zirconia, surfaces of metal-free FDPs and dental hard-tissue surfaces when sandblasting is contra-indicated as described. The following is a short list of the limitations and adverse effects of the main detergents used in clinical practice before bonding procedures:

• Ethanol: It is not a very effective contaminant remover and is not able to remove saliva and blood proteins fully. Often ethanol fixates proteins rather than removing them.
• Sodium hypochlorite: It has good efficacy as a cleaner, including removal of saliva and blood proteins, but may have an adverse impact on bonding procedures owing to its oxidisation properties (free radicals released from a sodium hypochlorite reaction could result in interference with autopolymerisation and light polymerisation of resin monomers).¹
• Hydrogen peroxide: It does not have any contaminantremoving properties and, to a greater extent than sodium hypochlorite, could result in interference with free-radical polymerisation of resin-based materials used for adhesive procedures.
• Chlorhexidine: It does not have any adverse effect but also no capability of removing contaminants.

KATANA™ Cleaner and its specific features

KATANA™ Cleaner is a specific detergent solution for cleaning the surfaces of all kinds of prostheses, either metal based or metal free and for the adherent surfaces of dental hard tissue. KATANA™ Cleaner is for both extra-oral and intra-oral use. The chemical composition of KATANA™ Cleaner includes 10-MDP and a 10-MDP triethanolamine (TEA)-salt in an aqueous solution. 10-MDP-TEA is an emulsifier and surfactant compound able to solubilise many substances not soluble in water and to increase the wetting capacity of those. These chemical features of 10-MDP-TEA allow easier removal of contaminants from surfaces using water spray in order to obtain a clean surface. KATANA™ Cleaner is mainly targeting proteins; saliva, blood and the like. The 10-MDP-TEA-salt is amphiphilic. The non polair part enters the contamination forming micelles. the micelles are easy to rinse of with an air-water spray.

KATANA™ Cleaner is a powerful concentrated cleaner. It has a mild pH of 4,5 thus no adverse etching of the dental hard tissue. The presence of 10-MDP in the solution makes it compatible with all dental bonding agents. KATANA™ Cleaner is a purple-coloured solution, and this feature permits easy and accurate application on all surfaces to be cleaned. An easy flow chart follows that explains the use of KATANA™ Cleaner after try-in with glycerine paste before adhesive cementation of (metal-free) FDPs.

Fig. 1. Using KATANA™ Cleaner on the bonding surfaces of metal-free fixed dental prostheses and dental hard tissue after try-in and before bonding.

Fig. 2. Ceramic partial fixed dental prostheses (veneers) before the try-in.

Fig. 3. Glycerine paste used for the try-in.

Fig. 4. Veneer try-in.

Fig. 5. Use of KATANA™ Cleaner to remove remains of try-in gel and contaminants, such as saliva, from the bonding surfaces of the fixed dental prostheses.

CLINICAL CASE 1

Cleaning of "KATANA™ Zirconia" UTML FDPs after try-in using KATANA™ Cleaner

Fig. 6. "KATANA™ Zirconia" UTML fixed dental prostheses.

Fig. 7. Cleaning the fixed dental prostheses with KATANA™ Cleaner after the try-in.

Fig. 8. Tooth preparation cleaned with KATANA™ Cleaner before adhesive application and resin cementation.

Fig. 9. Fixed dental prostheses in situ at the recall appointment.

CLINICAL CASE 2

Tooth surface cleaning using KATANA™ Cleaner

Fig. 10. Ceramic partial fixed dental prostheses (veneers) before try-in and bonding procedures.

Fig. 11. Cleaning of the dental hard-tissue bonding surfaces in a clinical situation where sandblasting was not recommended owing to the high risk of periodontal soft-tissue bleeding.

Fig. 12. Bonded partial fixed dental prostheses at the recall appointment.

Fig. 13. Perioral aspect of the veneers during smiling.

Dentist:

DR STEFANO DANIELE

Dr Stefano Daniele received his dentistry degree from the University of Milan in Italy in 2001. He is in private practice in Milan and is an academic tutor in restorative dentistry in the Department of Biomedical, Surgical and Dental Sciences at the Faculty of Medicine of the University of Milan and is located at the San Paolo hospital in Milan. He was a visiting professor at the Università degli Studi del Piemonte Orientale “Amedeo Avogadro” in Novara in Italy, teaching restorative dentistry and dental materials until 2013.

Acknowledgements

Special thanks go to master dental technician Daniele Rondoni for the fabrication of the metal-free FDPs.

Reference

1. Lai SC, Mak YF, Cheung GS, Osorio R, Toledano M, Carvalho RM, Tay FR, Pashley DH. Reversal of compromised bonding to oxidized etched dentin. J Dent Res. 2001 Oct;80(10):1919–24. doi: 10.1177/00220345010800101101.

Ik ontvang regelmatig vragen over de intraorale reparatie van chippings bij porselein. Met oog op een succesvolle reparatie dient er serieus rekening te worden gehouden met verschillende essentiële zaken. De meest wezenlijke kwestie is wellicht inzicht in de primaire reden waarom de chipping zich voordeed. Als overbelasting bijvoorbeeld de belangrijkste reden is, dient daarmee rekening te worden gehouden tijdens de reparatie. Andere zaken die een rol spelen, zijn verwijdering van contaminatie, optimaal opruwen en chemische activering van het oppervlak, evenals het voorkomen van contaminatie tijdens de reparatie. Bovendien moet een rubberdam worden gebruikt om het werkgebied te isoleren.

BASISPRINCIPES VAN ADHESIE

Het succes van adhesieve procedures staat of valt met de toepassing van de juiste substanties en methoden. Voor een succesvolle behandeling vragen verschillende oppervlaktypes vaak om een andere aanpak. Voor adhesie gelden echter drie basisprincipes, die moeten worden nageleefd om optimale resultaten te bereiken:
1) mechanische retentie via een opgeruwd oppervlak;
2) chemische activering door middel van chemisch actieve substanties;
3) hoog-energiek hechtoppervlak voor een optimaal samenspel (bevochtigend vermogen) tussen het oppervlak en het toegepaste medium. Contaminatie tast het hechtend vermogen aan en dient altijd te worden voorkomen of verwijderd.

FRACTUURTYPES

De meest voorkomende fracturen betreffen uitsluitend porselein; bij andere fracturen zijn de substructuren in PFZ- of PFM-voorzieningen blootgesteld.
In veel gevallen gaat het slechts om beperkte chipping van het porselein, bijvoorbeeld bij de incisale rand. Om in dergelijke gevallen een duurzame reparatie te realiseren, dient het hecht-/reparatiegebied eerst met een fijn diamantfreesje te worden vergroot om een ruime afschuining te creëren. Een fine-grit freesje verdient de voorkeur boven een medium of ruwe versie; een groter aantal ondiepe groeven zorgt namelijk voor een optimaler hechtoppervlak dan een kleiner aantal diepere groeven. Extra opruwen van het adhesieve oppervlak door zandstralen met aluminiumoxide (korrelgrootte 50 μm, druk 2 bar) wordt sterk aanbevolen om het oppervlak verder te vergroten. Bij reparatie van porseleinchippings waarbij de substructuur is blootgesteld, dient serieus rekening te worden gehouden met de behandeling van meerdere substraten; dat betekent dat het reparatieprotocol hierop moet worden aangepast.

Reinig het opgeruwde gefractureerde oppervlak grondig. Hiervoor is KATANA™ Cleaner het product bij uitstek. Dit is een veilig en gebruiksvriendelijk product met een hoog reinigingsvermogen; het kan intra- en extra-oraal worden gebruikt voor allerlei tandheelkundige substraten. Na spoelen en grondig drogen is het oppervlak gereed voor de volgende stap, namelijk chemische activering. CLEARFIL™ CERAMIC PRIMER PLUS bevat zowel silaan als MDP, en zorgt voor een effectieve behandeling van keramiek op siliciumbasis, metaaloxiden (zirkonium) en metalen. Na het aanbrengen en grondig drogen kan de composietrestauratie meteen - zonder een extra adhesieve stap - worden uitgevoerd. De composiet bij uitstek is een
duurzame flowable, namelijk CLEARFIL MAJESTY™ ES Flow. Dit product heeft een hoge buigsterkte, die zelfs hoger is dan die van de meeste pastacomposieten. Bovendien voegt het zich beter en gemakkelijker naar het oppervlak. Snel en gemakkelijk polijsten is, naast behoud van glans, ook een zeer gewaardeerde kwaliteit van CLEARFIL MAJESTY™ ES Flow.

TIPS EN HANDIGHEIDJES

• Gebruik cofferdam om het werkgebied te isoleren
• Schuin de chipping nadrukkelijk af met een fijn diamantfreesje
• Ruw het adhesieve oppervlak op, bij voorkeur via zandstralen
• Reinig het hechtoppervlak met KATANA™ Cleaner
• Breng CLEARFIL™ CERAMIC PRIMER PLUS aan op het volledige adhesieve vlak (inclusief blootgesteld zirkonium of metaal) en laat het goed drogen
• Dek blootliggend metaal af met een dunne laag CLEARFIL™ ST OPAQUER, gevolgd door lichtuitharding
• Gebruik een sterke flowable composiet zoals CLEARFIL MAJESTY™ ES Flow voor de reparatie

Innovation and workflow simplification made possible

In this edition of BOND, we're shining a spotlight on the innovation and workflow simplification made possible by high-quality products like our "KATANA™ Zirconia" range.

In an interview with Atsushi Matsumoto and Yuta Tajima about KATANA™ Zirconia YML these experts explain the benefits of this new material possessing different concentrations of yttria in a single blank, and highlight how its multi-layered nature allows practitioners to work with a nearly universal zirconia suitable for all cases.

Mathias Fernandez Lombardi has contributed an excellent article detailing the science behind "KATANA™ Zirconia", Kuraray Noritake Dental's brand new 4.4.1. kit is introduced and last, but certainly not least, Dr Stefano Daniele details his experiences with KATANA™ Cleaner.

Click here to read. Enjoy!

Start Reading: BOND | VOLUME 8 | 12/2021

Previous versions:

BOND | SPECIAL EDITION | 06/2021

BOND | VOLUME 7 | 10/2020

KLINISCHE CASUS DOOR
DR. NICOLA SCOTTI

Bij een posterieure restauratie met composiet spelen functionele aspecten zoals sluitende, anatomisch correcte approximale contacten en een natuurlijk gevormd - en slijtvast en antagonistvriendelijk - occlusaal oppervlak een belangrijkere rol dan een perfecte kleurmatch. Focus op de factoren die van invloed zijn op de betrouwbaarheid en levensduur van de restauratie en krijg de kleurmatch er bij zonder kleurbepaling. CLEARFIL MAJESTY™ ES-2 Universal is een composiet dat zich moeiteloos
aanpast aan de kleur van het aangrenzende tandweefsel. Voor posterieure toepassing volstaat de kleur U. Tegelijkertijd staat dit product garant voor de goede randaansluiting, lage krimp en hoge slijtvastheid, nodig voor uitstekende resultaten op lange termijn.

Fig. 1. Aanvangssituatie. Een flinke primaire cariëslaesie distaal in de tweede premolaar.

Fig. 2. Premolaar na isolering van het werkgebied met cofferdam, cariësexcavatie en preparatie.

Fig. 3. Plaatsing van een sectionele matrix en een wig om de pasvorm te optimaliseren. Beide worden op hun plaats gehouden door een separatiering, die de interproximale ruimte vergroot en zodoende uiteindelijk zorgt voor sluitende, anatomisch correcte approximale contacten.

Fig. 4. Opbouw van de approximale wand met CLEARFIL MAJESTY™ ES-2 Universal (kleur U) na selectief etsen van glazuur met fosforzuur (K-ETCHANT Syringe) en hechting met CLEARFIL™ SE Bond.

Fig. 5. Er is als composietcoating een dunne laag vloeibare composiet (CLEARFIL MAJESTY™ ES FLOW High) aangebracht over de bondinglaag op de caviteitsbodem.

Fig. 6. Restauratie voltooid met CLEARFIL MAJESTY™ ES-2 Universal (kleur U). Hoewel de composiet met universele kleur zich uitstekend voegt naar de omliggende tandstructuur, wordt de natuurlijke uitstraling vervolmaakt door toevoeging van een
minieme hoeveelheid bruine composiettint in de fissuur.

Fig. 7. Resultaat van de behandeling meteen na verwijdering van de cofferdam. Het contact is strak en de vorm van de occlusale anatomie sluit aan op de individuele kauwdynamiek van de patiënt. De rand van de restauratie is vrijwel onzichtbaar. De buccale knobbel lijkt lichter vanwege de dehydratie van de natuurlijke tandstructuur tijdens de behandeling.

EINDRESULTAAT

Fig. 8. Resultaat na twee maanden.

Conclusie

Deze casus toont aan dat de geselecteerde composiet zich uitstekend leent voor vereenvoudigde restauratieprocedures in het posterieure gebied. Het materiaal laat zich goed verwerken, biedt dezelfde mechanische eigenschappen als andere materialen uit de CLEARFIL MAJESTY™ ES-2-serie en voegt zich - zonder te translucent te zijn - harmonieus naar de omliggende structuren. Op deze manier kan kleurbepaling achterwege blijven, zonder dat er afbreuk wordt gedaan aan het eindresultaat. De bespaarde tijd kan worden besteed aan functionele aspecten.

Tandarts:

DR. NICOLA SCOTTI