Case by DT Andreas Chatzimpatzakis

AESTHETIC AND EFFICIENT SMILE MAKEOVER

Most patients asking for a smile makeover desire custom solutions rather than an off-the-peg smile: Individual tooth shapes that fit their face and their character, an internal play of colours that matches their age and natural dentition. Modern dental materials allow us to deliver what they demand in many situations – usually at a reasonable price.

For a long time, however, we have been facing challenges when combining cosmetic and medically indicated treatment – e.g. a smile makeover including the rehabilitation of a missing lateral incisor. A straightforward solution – using lithium disilicate veneers alongside a zirconia cantilever bridge, both finished with their respective porcelain systems – would have been complicated by potential differences in the final appearance. With CERABIEN™ MiLai (Kuraray Noritake Dental Inc.), a set of internal stains and porcelains designed for micro-layering, the situation is different: Suitable for micro-layering on zirconia and lithium disilicate, it supports its user ideally in creating a harmonious smile even when the two framework materials are combined.

A NEW CUSTOM SMILE

The following patient case is a perfect example: A female patient with a missing lateral incisor, multiple visible composite restorations in the anterior region and an enamel fracture at her incisal edge desired a smile makeover. The selected materials were Amber Press LT (HASS), shade A1, for four veneers on the central incisors and the left lateral incisor and canine (teeth # 11, 21, 22 and 23 according to the FDI notation) and KATANA™ Zirconia YML (Kuraray Noritake Dental Inc.), shade A2, for the planned cantilever bridge on the maxillary right canine, replacing the missing lateral incisor (teeth # 12 and 13).

Fig. 1. Female patient with a missing maxillary lateral incisor and multiple composite restorations in the anterior area – a smile makeover is desired.

Fig. 2. Patient with mock-up.

Fig. 3. Minimally invasive preparation through the mock-up, which takes into account the minimum space required for the planned materials and restorations.

Fig. 4. Teeth prepared for the all-ceramic restorations.

Fig. 5. Occlusal view of the maxillary teeth after tooth preparation.

Fig. 6. Full-contour veneers and cantilever bridge on the model.

Fig. 7. Restorations after a cutback limited to the vestibular and incisal area.

Fig. 8. CERABIEN™ MiLai LT₁ is applied to the middle and cervical area of the zirconia cantilever bridge.

Fig. 9. CERABIEN™ MiLai Value Liner 2...

Fig. 10. … and Value Liner 1 applied to the incisal area of the central and lateral incisor restorations.

Fig. 11. CERABIEN™ MiLai porcelain Creamy Enamel mixed with Value Liner 2 (70/30) added to the middle and cervical areas of the four lithium disilicate restorations to increase and control the value.

Fig. 12. ... while E2 is added to the incisal area of both canines.

Fig. 13. Restorations covered by a layer of Tx ...

Fig. 14. ... and LTx.

Fig. 15. Appearance of the restorations after the first bake.

Fig. 16. Adding translucency and opalescence to the cervical area with LT₁ and brightness to the ridges with Creamy Enamel.

Fig. 17. Completion of the enamel surface with a cover layer of LTx, which is responsible for a high translucency and opalescence.

Fig. 18. Result of the second bake.

Fig. 19. Final restorations with a natural self-glaze effect on the model.

Fig. 20. Final restorations with a natural self-glaze effect in the patient’s mouth.

Fig. 21. Smooth optical integration of the restorations.

Fig. 22. Beautiful treatment outcome.

CONCLUSION

With the described approach and selected materials, it was possible to create restorations with a natural shade, shape and texture. They matched not only the appearance of the remaining natural teeth, but also showed internal consistency across the selected framework materials. The technical procedure was quite straightforward and efficient, while the result speaks for itself.

Special thanks to Dr. Kanellos Ioannis for the collaboration on this case and for kindly providing the pre- and post-treatment photographs that complemented it.

Dental technician:

ANDREAS CHATZIMPATZAKIS

Based in Athens, Greece, Andreas Chatzimpatzakis is the founder and director of ACH Dental Laboratory (since 2000), specializing in refractory veneers, lithium disilicate, zirconia, and implant prostheses. He graduated in Dental Technology from the University of West Attica and received advanced training in all-ceramic restorations in Helsinki and Japan under renowned masters including Shigeo Kataoka.

Since 2017, he has served as an international trainer for Kuraray–Noritake Dental Inc., delivering lectures and hands-on courses worldwide on advanced ceramic techniques. He has also held roles as Key Opinion Leader for MPF Brush Co., Ambassador for Hass Co., and Editor-in-Chief of Laborama. An active member of the Hellenic Academy of Aesthetic Dentistry, his work and articles have been published in both Greek and international journals.

Case by Dt. Koray Kendir, DDS, Turkey (İzmir)

ABSTRACT

This clinical case report presents a posterior direct composite restoration performed using Kuraray Noritake Dental Inc.’s “Universal Excellence” product concept. A universal adhesive (CLEARFIL™ Universal Bond Quick 2) and a highly filled, universal-shade flowable composite (CLEARFIL MAJESTY™ ES Flow Universal) were utilized to achieve both simplicity and predictability. Step-by-step documentation demonstrates isolation, cavity preparation, deep margin elevation, adhesive protocol, and final restoration.

CASE DESCRIPTION

A 38-year-old female patient presented with complaints of interdental bleeding and cold sensitivity between her maxillary left canine and first premolar (teeth #23 and #24, FDI notation). Clinical examination revealed an open margin and secondary caries at the gingival floor of the existing restoration on tooth #23. After rubber dam isolation, the stepwise treatment procedure was initiated.

CLINICAL PROCEDURE

Step 1. Tooth #23 exhibited an open gingival margin and caries (Fig. 1).

Step 2. After enamel removal, caries was excavated down to the gingival level. The lesion on tooth #24 was observed to extend subgingivally (Fig. 2).

Step 3. After complete caries excavation and cavity refinement, the need for deep margin elevation (DME) on tooth #24 became evident (Fig. 3).

Step 4. Deep margin elevation (DME) was performed on tooth #24 using a custom sectional wedge. First, selective etching and CLEARFIL™ Universal Bond Quick 2 were applied, followed by the placement of CLEARFIL MAJESTY™ ES Flow Universal (Super Low) (Figs. 4 to 6).

Step 5. After completion of the DME (deep margin elevation), appropriate matrix bands were placed, followed by a direct restoration of teeth #23 and #24 with CLEARFIL MAJESTY™ ES Flow Universal (Super Low) (Figs. 7 to 9). Thanks to the material’s easy handling, shade adaptation, and excellent polishability, this challenging DME case was successfully and efficiently managed.

The treatment outcome is shown in Figures 10 and 11.

Fig. 1. Preoperative view under rubber dam isolation.

Fig. 2. Clinical situation after caries excavation.

Fig. 3. Refined cavities with a deep margin on the premolar.

Fig. 4. Custom wedge placed to elevate the margin.

Fig. 5. Buccal view of the teeth after deep margin elevation with universal products.

Fig. 6. Occlusal view of the teeth after deep margin elevation with universal products.

Fig. 7. Placement of a sectional matrix.

Fig. 8. Buccal view of the teeth restored with a universal-shade flowable composite with super low flowability.

Fig. 9. Occlusal view of the teeth restored with a universal-shade flowable composite.

Fig. 10. Occlusal view of the final restorations of teeth #23 and #24, showing colour blending, anatomical form, and surface gloss.

Fig. 11. Buccal view of the final restorations of teeth #23 and #24, showing colour blending, anatomical form, and surface gloss.

DISCUSSION

Universal adhesives and modern flowable composites simplify posterior direct restorations by reducing technique sensitivity while providing for durable outcomes. In this case, CLEARFIL™ Universal Bond Quick 2 provided strong adhesion with minimal application time. The universal flowable composite demonstrated excellent adaptability, polishability, and durability. Even with a subgingival margin requiring DME, a streamlined approach was achieved without compromising quality.

CONCLUSION

The combination of CLEARFIL™ Universal Bond Quick 2 and CLEARFIL MAJESTY™ ES Flow Universal allows clinicians to perform predictable, efficient posterior restorations. Their universal applicability and handling properties align with the “Universal Excellence” concept, supporting simplified, yet reliable daily practice.

Ethics & Disclosure

All procedures were performed in accordance with standard dental practice. The patient provided informed consent for treatment and publication of anonymized clinical images. Author collaborates with Kuraray Noritake Dental Inc. as an advisor; content reflects clinical experience.

Dentist:

KORAY KENDIR

Dt. Koray Kendir is a graduate of Hacettepe University Faculty of Dentistry and the co-founder of a private dental clinic in İzmir. He specializes in digital dentistry, smile design, and computer-aided restorative treatments. Known for his innovative approach, Dr. Kendir is a frequent speaker at national dental congresses and serves as an advisor to several dental companies.

HOW TO OPTIMIZE ALL-CERAMIC RESTORATION BOTH AESTHETIC AND MECHANICAL?

A homogeneous porcelain structure, a strong bond between framework and veneering layer and a natural play of colours: All those characteristics of a high-quality all-ceramic restoration are not only strongly dependent on manual skills of the dental technician, but also on ideal firing conditions.

Only with a well maintained and properly functioning furnace and the right protocols, it is possible to obtain consistently great results in terms of aesthetics and function.

This is true for all kinds of all-ceramic restorations consisting of a framework and a veneering layer: It applies to full layering with a classical anatomical framework design and a relatively thick layer of porcelain, as well as to various cut-back designs finished using the modern micro-layering technique. A material that belongs to the latter category of porcelains and is becoming increasingly popular among dental technicians worldwide is CERABIEN™ MiLai (Kuraray Noritake Dental Inc.). The set of low-fusing porcelains and internal stains has been specifically developed for micro-layering, and works well with different variants of lithium disilicate and zirconia.

While the firing parameters provided by manufacturers like Kuraray Noritake Dental serve as reliable and thoroughly tested guidelines, experienced technicians often explore beyond these standards to achieve the highest possible aesthetic and functional outcomes.

This is precisely what MDT Nondas Vlachopoulos has done with CERABIEN MiLai.

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High-quality treatment is probably the most important element on the road to patient satisfaction. During every single appointment, the patient wants to feel well cared for by a skilled professional, while chair time and the number of appointments should be reduced to the necessary minimum. This implies that, in the context of prosthodontic treatment, a restoration needs to fit perfectly straight away and be stable over time to avoid remakes and extra appointments.

As explained in the first part of this series of articles, the quality of the selected prosthetic material – e.g. zirconia – has a decisive impact on the design, overall quality and long-term performance of definitive restoration. That is why you as a dental practitioner should

• order restorations that are produced domestically or in a region with the same standards as your own,
• know about the source of the zirconia your laboratory partner uses, and
• avoid deals that are too good to be true.

WHY ASK YOUR LABORATORY TO USE KATANA™ Zirconia

When quality matters, and you want to be sure that the zirconia restorations from your dental laboratory partner offer the desired mechanical and optical properties, requesting KATANA™ Zirconia can be a wise choice. This family of high-quality dental materials provides laboratories with everything they need to deliver restorations that you and your patients will appreciate, regardless of indication and no matter how unique the requirement. This is largely thanks to two factors: sophisticated multi-layered technology and a meticulous blank production process.

THE KEYS TO BRILLIANT AESTHETICS

Early zirconia materials often had a whitish, opaque appearance and were used mainly as framework materials. On the other hand, the dental zirconia used by dental laboratories today is typically pre-shaded and available in various levels of translucency. Some blanks even offer multi-layered technology: Recognising the importance of varying chroma and translucency in different areas of a natural tooth, Kuraray Noritake Dental Inc. has pioneered this trend. In 2013, the company became the first to introduce a blank with a polychromatic structure (KATANA™ Zirconia ML), featuring a natural gradient in chroma and a seamless transition between layers for a tooth-like appearance.

Initially developed for monolithic restorations, which are just polished or characterized with external stains and glazed, this new type of zirconia also inspired the micro-layering technique. Here, restorations are designed in full contour with only a slight cutback in the vestibular area, allowing for subtle porcelain effects that replicate the optical properties of enamel.

Continuous improvements of this first multi-layered zirconia generation ultimately resulted in the current zirconia portfolio offered by Kuraray Noritake Dental Inc. It consists of a multi-layered block for chairside milling machines, a classical framework material, and the KATANA™ Zirconia Multi-Layered discs series – even including a blank with flexural strength gradation:

Fig. 1. Four-layer colour structure of the KATANA™ Zirconia Multi-Layered series

KATANA™ Zirconia Block – Multi-layered block for chairside milling (available for CEREC and other chairside milling machines), with an 18-minute speed-sintering option* for natural tooth-coloured single restorations and short-span bridges.

^{*Speed-sintering option available only with compatible furnaces.}

KATANA™ Zirconia HT – High-strength zirconia for single-unit copings and long-span bridge frameworks, available in five different disc thicknesses.

KATANA™ Zirconia UTML – Ultra-translucent zirconia with a multilayered colour structure, ideal for monolithic anterior restorations including veneers.

KATANA™ Zirconia STML – Balanced translucency and strength for beautiful monolithic restorations, with natural colour gradation. This variant is ideal for crowns and up to three-unit bridges.

KATANA™ Zirconia HTML PLUS – High-translucency option with the strength needed for long-span bridges, offering vivid, natural colour.

KATANA™ Zirconia YML – Advanced zirconia with colour, translucency and strength gradation, featuring a strong body and highly translucent enamel layer for a virtually unlimited indication range.

THE KEYS TO HIGH-QUALITY RESTORATIONS

Zirconia quality depends on factors such as raw material purity, chemical composition, grain size and particle distribution. Every stage of production – from powder preparation to pressing and pre-sintering – affects the final mechanical and optical properties. Kuraray Noritake Dental Inc. optimises each of these steps to achieve consistently high quality.

1. RAW MATERIALS

Unlike most manufacturers who purchase pre-fabricated powders (from partners like Tosoh Corporation), Kuraray Noritake Dental Inc. produces all components in-house, including zirconium oxide, yttrium oxide, aluminium oxide, and those elements forming the company’s proprietary multilayer technology. This innovative technology is used to form a polychromatic blank structure and – in the case of KATANA™ Zirconia YML – additional translucency and flexural strength gradation.

Fig. 2. Powder for KATANA™ Zirconia

BENEFITS

• Natural translucency
• Shades matching VITA classical A1-D4™ shade guide concept
• Well-balanced flexural strength
• Precise millability for outstanding fit
• High ageing resistance
• Predictable sintering performance

2. PRESSING

A uniform density distribution throughout the blank and homogeneous material structure are essential for predictable processing outcomes and accurate fit. Kuraray Noritake Dental Inc. uses a unique pressing process that is designed to create even pressure distribution, minimise airborne particle contamination and reduce gravitation forces. This results in the desired purity and density of the zirconia blanks.

BENEFITS

• Uniform mechanical and optical properties
• Outstanding edge stability
• High surface quality
• Controlled sintering deformation

3. PRE-SINTERING

Pre-sintering gives pressed blanks the stability needed for milling. The selected temperature profile and duration of the pre-sintering cycle determine the material’s strength and hardness and processing properties, and have an impact on the final sintering process. The procedure used by Kuraray Noritake Dental Inc. results in blanks that are stable yet easily machinable with standard diamond-coated tools, without increased breakage risk or excessive tool wear.

Fig. 3. Restoration margins have been milled to a very thin profile, and yet they still show smooth margins without any chipping

BENEFITS

• High surface quality after milling
• Shorter sintering times possible (54 minutes for single tooth restorations and bridges with up to three units made of KATANA™ Zirconia UTML, STML, HTML PLUS or YML; 18 minutes in the case of KATANA™ Zirconia Block)

EVERYTHING YOUR LABORATORY PARTNERS NEED

Whether your partners in the laboratory prefer to work with different zirconia variants tailored to specific needs or a single material for all indications, whether they prefer full porcelain layering or simplified finishing techniques: KATANA™ Zirconia delivers the versatility needed – with a consistently high quality aimed at exceeding expectations.

Knowing this – and knowing how to distinguish high from poor quality zirconia materials – allows you to contribute significantly to the high quality of the prosthetic work produced in the dental laboratory. If you then also establish a well-structured, standardized and bidirectional flow of information maintaining records between practice and laboratory (e.g. by using checklists or a digital platform), all members of the restorative team are able to perform at their best for predictable treatment outcomes and long-term success.

COMPLEMENTARY PRODUCTS FOR THE DENTAL PRACTICE

Regarding the remaining clinical steps like the successful cementation of the delivered zirconia restorations, Kuraray Noritake Dental Inc. is a trustworthy partner, too: As well as offering complementary products for polishing, staining, glazing and veneering of zirconia restorations, the company is also a leading provider of clinical products such as resin cements, adhesives and cleaning agents. KATANA™ Cleaner, for example, can be applied both intra-orally and extra-orally, removing contamination from the bonding surfaces (tooth and restoration) after try-in. Applied to the pre-treated surface directly after cleaning, high-performance resin cement systems like PANAVIA™ V5 establish a strong bond to tooth structure and zirconia (as well as other restorative materials), so that high success rates are achieved even with partial restorations that offer minimal macro-mechanical retention1,2. Finally, if modifications are needed, TWIST™ DIA for Zirconia is a great option. It is suitable for polishing intra-orally and delivers a natural surface gloss. The products are well aligned and designed to complement each other for smooth workflows and outstanding results.

Literature

1. Blatz MB, Alvarez M, Sawyer K, Brindis M. How to Bond Zirconia: The APC Concept. Compend Contin Educ Dent. 2016 Oct;37(9):611-617; quiz 618. PMID: 27700128.
2. Alqutaibi AY, Alghauli MA, Almuzaini SA, Alharbi AF, Alsani AA, Mubarak AM, Alhajj MN. Failure and complication rates of different materials, designs, and bonding techniques of ceramic cantilever resin-bonded fixed dental prostheses for restoring missing anterior teeth: A systematic review and meta-analysis. J Esthet Restor Dent. 2024 Oct;36(10):1396-1411.

Case by Andreas Chatzimpatzakis

For zirconia-based screw-retained implant-supported prostheses, diverse finishing concepts are available. Most of them are quite complex and time-consuming. A streamlined approach that brings efficiency into the finishing procedure without compromising aesthetics and function is micro-layering with CERABIEN™ MiLai (Kuraray Noritake Dental Inc.) on a zirconia superstructure with just a slight vestibular cutback. A possible technical procedure is demonstrated using the following case example. The patient was treated by prosthodontist Dr. Georgios Siavikis from Ioannina, Greece.

Fig. 1. Occlusal view of an implant-supported overdenture made of KATANA™ Zirconia HTML PLUS (Kuraray Noritake Dental Inc.) for a male patient with an edentulous maxilla and a removable partial denture in the mandible.

Fig. 2. Frontal view of the milled and sintered screw-retained implant-supported prosthesis.

Fig. 3. Appearance after the application of CERABIEN™ MiLai SS Fluoro and internal stains to enhance the natural shading of the restoration in the tooth and gum areas.

Fig. 4. Result of micro-layering with CERABIEN™ MiLai porcelains LT1 for the cervical as well as E2 and TX for the middle and incisal sections for a seamless gradient in translucency. For an optimal gingival harmony and match with the surrounding tissue, the tissue shades 1, 5 and 6 were applied.

Fig. 5. The restoration after finishing.

Fig. 6. The gingiva and tooth areas have a natural appearance …

Fig. 7. … due to a natural colour, translucency and surface texture.

Fig. 8. Intraoral harmony.

PREDICTABLE OUTCOMES

In this case, the use of an aesthetic, high-strength multi-layered zirconia was a true enabler of a streamlined finishing technique. As a convinced and frequent user of CERABIEN™ ZR, micro-layering with CERABIEN™ MiLai appeared to work flawlessly right from the start. The systems are perfectly aligned to each other, and as they are both based on synthetic feldspathic technology, they offer consistent material properties. These provide precise control over the layering and shading, thus supporting a highly aesthetic and well-integrated implant restoration.

Dental technician:

ANDREAS CHATZIMPATZAKIS

Andreas graduated from the Dental Technology Institute (TEI) of Athens in 1999. During his studies he followed a program at the Helsinki Polytechnic Department of Dental Technique, where he trained on implant superstructures and all ceramic prosthetic restorations. As of 2000, he is running the ACH Dental Laboratory in Athens, Greece, specialized on refractory veneers, zirconia and long span implant prosthesis. In 2017 Andreas visited Japan where he trained under the guidance of Hitoshi Aoshima, Naoto Yuasa and Kazunabu Yamanda and become International Trainer for Kuraray Noritake Dental Inc..

Article by doctors Tom Boujenah and Olivier Boujenah.

KEEP IT SIMPLE WHILE MEETING THE PATIENT’S INDIVIDUAL DEMANDS

Every day in our practices, we are faced with a choice between different treatment options. Experience, scientific literature, and patient preferences all help guide us toward one direction or another.

The case presented below could have been managed using a different approach, but the chosen solution aligned with our philosophy: keep it simple while meeting the patient’s individual demands.

A PATIENT WITH HIGH AESTHETIC DEMANDS

A young patient, in his early twenties, presented for consultation with a purely aesthetic concern. He had been wearing a double-retainer resin-bonded fixed dental prosthesis (Maryland bridge) (Figure 1) for several years, placed due to the congenital absence of the mandibular central incisors. Although the bridge had served him well functionally, the patient now wished to replace it with a more aesthetic solution, better matching the current shade of his natural teeth. After clinical and radiographic assessment, several treatment options were considered, taking into account the patient’s age, bone volume, and aesthetic expectations.

The final decision was to fabricate a new resin-bonded bridge, optimized in terms of both design and shade, using a multilayered zirconia to achieve a natural-looking result.

Fig. 1. Initial situation

Fig. 2. iTero 5D+ optical scan

PRELIMINARY STEPS IN THE DENTAL OFFICE

A pre-treatment impression of the bridge was taken before removal, using the iTero 5D+ scanner (Align Technology; Figure 2). These pre-treatment scans, which are performed almost systematically for our prosthetic reconstructions, allow the laboratory to capture the volume of the existing prosthesis, replicate the previous shape (if suitable), and often visualize wear facets. This helps minimize or even eliminate the need for subsequent adjustments. Then, the existing resin-bonded bridge was removed, and the abutment teeth were prepared as minimally invasive as possible. Once again, the intraoral scanner was used to take an impression of the situation (Figure 3).

Fig. 3. Impression after bridge removal and minimal preparation of the lingual surfaces

PRODUCTION OF THE RESIN-BONDED BRIDGE

The scan was sent directly from the intraoral scanner to the Design4me platform (a 3D design platform) to carry out the digital design of the planned bridge (Figures 4 and 5). A repositioning key was also designed by the dental technicians to provide for accurate seating of the bridge during cementation (Figure 6). The material of choice was KATANA™ Zirconia YML, a multi-layered zirconia from Kuraray Noritake Dental Inc., shade B1. It seemed most appropriate due to its outstanding physical and aesthetic properties—specifically its gradient in shade translucency and flexural strength (Figure 7).

Fig. 4. Design of the new bridge using exocad software (Design4me platform)

Fig. 5. View of the soft tissue underneath the bridge showing slight gingival compression

Fig. 6. Repositioning key designed using exocad software (Design4me platform)

Fig. 7. KATANA™ Zirconia YML disc (shade shown not representative of the case presented)

The production centre, DIGISMILE, subsequently received the STL files of the bridge and the positioning key, modeled by the dental technicians on the Design4me platform, ready for milling and printing. We also provided the laboratory with intraoral photos to replicate the surface texture, possible characterizations, and shades. The laboratory performed the milling of the bridge using a DWX-52D milling machine (Roland DG). Polishing, surface finishing, and staining were carried out using Komet burs and Miyo liquid porcelain (Jensen). The repositioning key, meanwhile, was 3D printed with a NextDent 5100 3D Printer (3D Systems) using surgical guide resin (Figure 8).

Fig. 8. Milled bridge and 3D-printed key after polishing and staining

DEFINITIVE PLACEMENT IN THE DENTAL OFFICE

The adhesive cementation procedure is one of the most critical steps of the whole workflow. Once the bridge had arrived in the dental office and try-in was successfully completed, the focus was on moisture control and the establishment of ideal bonding conditions. In this context, strict working field isolation with saliva ejectors, cotton rolls, and ideally a rubber dam is essential, followed by the pre-treatment of the abutment teeth and the retainer wings of the zirconia bridge.

PRE-TREATMENT OF THE TOOTH STRUCTURE

Since the tooth preparations are strictly limited to enamel, the following conservative bonding protocol was adopted:

• Etching with phosphoric acid for 30 seconds on the enamel surfaces.
• Thorough rinsing with water, followed by gentle drying without desiccating the enamel.
• Application of PANAVIA™ V5 Tooth Primer (Kuraray Noritake Dental Inc.), followed by thorough drying with mild air after a 20-second waiting time. This primer contains MDP, which is essential for reliable enamel/zirconia adhesion.

PRE-TREATMENT OF THE ZIRCONIA WINGS OF THE BRIDGE

Even though the intaglio surface was sandblasted in the laboratory, it is crucial to repeat this step in the clinic:

• Cleaning with KATANA™ Cleaner (Kuraray Noritake Dental Inc.) for 10 seconds or ultrasonic cleaning for 5 minutes, followed by rinsing with water.
• Sandblasting with 50 μm aluminum oxide (Al2O3) at 2 bar.
• Application of CLEARFIL™ Ceramic Primer Plus (Kuraray Noritake Dental Inc.) to the intaglio surface without rinsing, followed by gentle drying. This primer also contains MDP, providing for a proper chemical bond to zirconia.

ADHESIVE CEMENTATION

With all surfaces pre-treated appropriately, adhesive cementation proceeded as follows:

• Application of PANAVIA™ V5 Paste (universal shade A2) to the intaglio of the bridge.
• Insertion of the bridge using the repositioning key.
• Light curing (“tack” cure) for 3 to 5 seconds to stabilize the restoration.
• Removal of excess resin cement with a dental explorer. Alternatively, excess may be removed immediately with a soft brush before applying to light cure for the margins.
• Final complete light curing according to the manufacturer’s instructions (Figures 9 and 10).

Fig. 9. Clinical situation captured immediately after cementation

Fig. 10. Lateral view of the restoration immediately after cementation

TREATMENT OUTCOME

Thanks to the pre-treatment scan and the overlay of the old bridge with the new one, no adjustments were necessary, although occlusion control remained essential. At a recall after 18 months, gingival integration was satisfactory: The patient was able to use interdental brushes and maintain the prosthesis properly (Figures 11 and 12).

Fig. 11. Clinical situation 18 months after definitive placement

Fig. 12. Lateral view at 18 months

CONCLUSION

In this clinical case, the choice to produce a double retainer resin-bonded bridge, almost identical in design to the previous one, may seem conservative. However, this decision is supported by several factors: The patient’s good tolerance of the previous prosthesis, the tissue integrity of the abutment teeth, and, most importantly, the opportunity to significantly improve aesthetics thanks to advances in materials and bonding techniques, which allowed us to keep preparations minimal and minimally invasive.

This new bridge, designed with highly aesthetic multilayer zirconia and bonded using a strict protocol, achieved a perfectly integrated and natural result without resorting to more invasive options (therapeutic gradient). Furthermore, this approach invites the restorative team to consider emerging trends in resin-bonded bridge design, notably the option of two single-retainer cantilever bridges, which might be considered in similar cases in the future.

This case highlights the importance of individualized treatment planning, which does not rely solely on innovation, but on precise clinical assessment, attentive listening to patient needs and expectations, careful implementation of available tools, and the use of high-quality materials and protocols.

Dentists:

OLIVIER BOUJENAH

Dr. Olivier Boujenah earned his Doctorate in Dental Surgery from Paris V in 1994 and a University Diploma in Maxillofacial Surgical Rehabilitation from Paris VII in 2008. A pioneer in digital dentistry, he founded DIGISMILE, a training center and fully digital laboratory, and DIGISMILE LAB, dedicated to prostheses and surgical guides. He teaches in the Master’s program in Digital Dentistry at the University of Geneva and has pursued advanced training at Harvard University in digital workflows and guided surgery.

TOM BOUJENAH

Dr. Tom Boujenah graduated from the European University of Madrid in 2023 and completed a University Diploma in Oral Implant Rehabilitation at the Pitié-Salpêtrière Hospital in Paris. Based in private practice in the 16th district of Paris, he focuses on aesthetic and functional oral rehabilitation with a particular interest in implant dentistry and digital workflows. Passionate about innovation, he integrates the latest advances in implantology, prosthodontics, and digital dentistry to deliver personalized and long-lasting treatments.

The impact of a material switch in the dental laboratory

Switching to a different type of zirconium is not something you do lightly. Was the leap to KATANA™ Zirconia worth it? Three dental lab owners share their experience!

Not all zirconium oxide materials are created equal. Dental technicians worldwide recognise that zirconium oxide discs vary significantly in quality depending on their composition and manufacturing process. The most noticeable differences lie in their mechanical and optical properties, both of which are determined during production. At first glance, zirconium oxide products from leading manufacturers may seem similar. However, —sometimes invisible—differences can exist. Achieving the highest quality requires the use of premium raw materials, advanced cleaning and pressing techniques, and precise pre-sintering methods. These factors help ensure superior results while minimizing the risk of remakes. Selecting a high-quality zirconium oxide product is crucial, particularly when working with complex structures or specialised processing techniques. The right choice can significantly impact the final outcome and durability of dental restorations.

We had a conversation with three decision makers of Norwegian dental laboratories to learn more about their reasons to switch to the KATANA™ Zirconia Multi Layered Series (Kuraray Noritake Dental Inc.) and their path to success with these materials. Espen Rørstad is the owner and general manager of Vestfold Dental in Tønsberg, Lucas Andvik the general manager of Cicero Dental AS in Trondheim and Hilsen Egil Berg the general manager of dental technology at Berg Dental in Askim. They are happy to share their experience and practical tips and tricks.

Time for change

The reasons to start testing alternative zirconium oxide materials were different: Espen Rørstad, who has been a dental technician for 24 years, was looking for improvements in strength and aesthetics: “Nowadays, zirconium materials are evolving quickly, and specifically those blanks with multi-layered colour, translucency and flexural strength attracted my attention. I first tested a material from another leading manufacturer. Then, I received a single disc of KATANA™ Zirconia YML. I was immediately impressed by the homogeneous, densely pressed material and its optical properties. Ever since my first trial case with KATANA™ YML, I have not used any other zirconium oxide again.”

Choosing the right material

Hilsen Egil Berg uses KATANA™ Zirconia YML for most indications, and KATANA™ Zirconia HTML Plus for large reconstructions of ten or more units. The design is predominantly monolithic with a small (vestibular) cutback. The approach of Espen Rørstad is similar. He also uses KATANA™ Zirconia YML on a regular basis for reconstructions with up to ten units, even on implants in combination with Ti-bases. “For larger-span restorations, I most frequently opt for KATANA™ Zirconia HTML Plus or, occasionally KATANA™ Zirconia HT combined with a traditional layering approach”. Lucas Andvik uses all four types of multi-layered zirconia from Kuraray Noritake Dental Inc. (KATANA™ Zirconia UTML, STML, HTML Plus and YML) to have the best of all worlds.

Establishing workflows

Switching materials always means investing time and effort until processes run smoothly and predictably. According to Espen Rørstad, it did not take long with KATANA™ Zirconia to get the parameters right and obtain high-quality results. According to him, a factor that is critical for good outcomes with KATANA™ Zirconia YML is positioning of the restoration in the disc. “Proper positioning is key to success – long-span reconstructions are only stable if positioned according to the manufacturer’s recommendations. The learning curve is quite steep and we have no issues with fractures,” he says. Lucas Andvik slightly adjusted his production procedure to provide for great outcomes: “Initially, we tried to position our restorations in blanks of the heights we had used before, and this turned out to be quite challenging. In order to have enough space for the connectors and be able to position long-span restorations in the middle of the disc as recommended, we started utilising higher blanks. With this strategy, the initial challenges were a thing of the past.”

What makes KATANA™ Zirconia different

KATANA™ Zirconia is engineered with precision at every step of the production process, from raw powder production to disc pressing, every step is tightly controlled for consistency and quality. It’s the result of decades of expertise in ceramics and full in-house control. Every disc reflects that precision and expertise, offering you high quality zirconium oxide with outstanding features;

• Dual gradient structure (YML): A seamless transition in both translucency and strength.
• High green-state stability: Thin margins, no chipping. Fewer sprues, smoother carving, and optimal material use.
• Targeted yttria balance: Optical translucency where needed, strength where it matters, each layer is purposefully composed.
• Speed sintering: 54-minute cycles delivering consistent aesthetics and mechanical performance.
• Optimized density and CTE: Uniform density and a stable coefficient of thermal expansion in all layers ensure minimized sintering deformation and high fitting accuracy.

Easy carving

One of the practical benefits of using KATANA™ Zirconia is the fact that it is perfectly suitable for carving. Lucas Andvik states: “Carving is easier with KATANA™ Zirconia than with other materials. It is even possible to go close to the margins without increasing the fracture risk. Other materials seem to be much less dense and softer, which may result in marginal fractures. Carving is really a feature that transformed our inhouse production procedure and contributes to great outcomes.” Espen Rørstad and Hilsen Egil Berg agree that carving feels great with this material, while the former also stresses that the overall aesthetics when using the carving technique are very well received by partners from dental offices.

Mastering the sintering process for optimal results

A procedure known as a critical step in the production procedure is the sintering. Virtually every leading manufacturer of hightranslucency zirconium oxide advises users to calibrate furnaces and check the achieved temperatures on a regular basis to provide for optimal outcomes. The actual sintering protocols recommended for each material, however, are very different. Kuraray Noritake Dental Inc. offers three sintering programms valid for all four materials of the KATANA™ Zirconia Multi-Layered series: The standard sevenhour programme is available for all kinds of prostheses, while the high-speed 54-minute and 90 minute programmes are suitable for restorations with up to three units. For KATANA™ Zirconia Blocks, even18-minute sintering is possible. Lucas Andvik uses the seven-hour programme for over-night sintering of all large restorations, and speed sintering for single-tooth restorations and small bridgeworks during the day. With his new furnace, he simply adopted the recommended protocols. Espen Rørstad modified the protocols slightly for his furnace and regards speed sintering as a great option for rush cases. Hilsen Egil Berg prefers over-night sintering. He reports: “It is really important to have a high-quality, modern furnace, calibrate it regularly and follow the manufacturer’s instructions. My recommendation for everyone experiencing issues is to pay extra attention to warming up and cooling down properly. That way, you achieve the highest possible strength and aesthetics, including an absolutely smooth transition between the different layers in the blank.”

Micro-layering: A game changer for finishing

In all three dental laboratories, the integration of KATANA™ Zirconia has led to a shift towards higher-efficiency finishing approaches. Espen Rørstad reports: “The switch to KATANA™ Zirconia enabled us to increase the amount of monolithic and micro cut-back zirconium oxide restorations from around 40 to 80 percent. In the anterior area, we use a minimal vestibular cutback and micro-layering, while the restorations are purely monolithic and only minimally pre coloured in the posterior area. Classical layering is only delivered on special request.” Hilsen Egil Berg states: “We completely stopped using traditional porcelain layering approaches and prefer micro-layering instead – especially in combination with KATANA™ Zirconia YML. The aesthetic outcomes are so good that a cosmetic dentist recently called me and asked if I had used lithium disilicate instead of zirconium.” Lucas Andvik also likes to add a little bit of porcelain: “We moved away from a full cutback to micro-layering approaches, using the same porcelain system for lithium disilicate and zirconium oxide,” he says. In subgingival areas, he often just polishes the restorations for highest biocompatibility, a concept that is very well received by dental practitioners.

Happy with the results?

Hilsen Egil Berg concludes: “Once you have implemented the workflow and set all parameters, working with KATANA™ Zirconia is really great. My staff likes its handling during carving, the efficient workflows and predictable results. Although sometimes the product may be more expensive than other brands’ zirconium oxide, the total economy is a lot better: We do no longer face any issues with fractures and remakes, and due to the homogeneous material structure, the service life of our milling tools is extended, while, at the same time, the edge stability of the milled restorations is increased. The blanks are so homogeneous that I am able to sinter long-span restorations without a lateral support!”

The conclusion of Lucas Andvik is similarly good: "everyone in my laboratory working with KATANA™ Zirconia is more than satisfied. My co-founder, Katharina, has tested many different materials on behalf of notable manufacturers and has never seen anything that compares to KATANA™. All the technicians that work with KATANA™ here consider it to the most versatile and aesthetic we have ever utilized. I think that all four variants are super nice to work with. My personal recommendation is to attend one of the courses offered by Kuraray Noritake Dental Inc. The instructors are super knowledgeable and we got a completely new conception of zirconium oxide as well as practical advice that was really useful for our daily work.”

Espen Rørstad is sure that “in terms of aesthetics, KATANA™ Zirconia is the best zirconium oxide tested, and I really tested a lot in the past decades! I am happy with the material, the interaction with the Kuraray Noritake Dental team and the support offered. My team is also happy with the material, but even more important is the positive feedback of my customers: One of them requested a specific zirconium all the time, and when we switched, we did not tell him immediately. Now he knows and is very happy with what he gets.” Espen is sure that economically, KATANA™ Zirconia YML is even able to compete with cheap zirconium oxide brands, as the production procedure is much more efficient and the results are predictable.

Switching zirconium oxide materials is a significant investment in both time and resources, but for many dental laboratories, the results speak for themselves. The experiences shared by these Norwegian technicians demonstrate that KATANA™ Zirconia offers a balance of aesthetics, strength, and efficiency. While adapting to new workflows takes effort, the improved outcomes, fewer remakes, and enhanced handling make the transition worthwhile. For those considering the switch, thorough testing and training are key to ensuring a smooth and successful integration.

PRACTICAL IMPLEMENTATION TIPS

• Review and adjust milling, sintering, and finishing protocols to match the manufacturer’s recommendations.
• Train technicians on best practices for positioning restorations within the blank to ensure strength and aesthetics.
• Optimise material selection for different cases
• Regularly calibrate sintering furnaces and check temperature accuracy to avoid issues like fractures or compromised aesthetics.
• Work closely with the supplier for technical support and guidance when setting up new workflows.

Case by MDT Andreas Chatzimpatzakis and DDS Manousos Pissadakis

ONE SOLUTION, MULTIPLE NEEDS COVERED

The treatment of young patients with a dental condition that affects the appearance of multiple teeth – like enamel hypomineralisation or hyperplasia – is particularly challenging for the restorative team. Dental practitioners and technicians need to be aware of the fact that the condition often involves a life-long disease burden, which typically goes hand in hand with an immense treatment need and increasingly invasive measures required with advancing age. It is their task to make the situation as bearable as possible for patients by delivering treatment that is very well aligned to their specific aesthetic, functional and financial needs, both in the short and long term.

Whenever all-ceramic restorations seem most appropriate, material and technique selection are particularly important: Protection of the affected teeth from extrinsic influences, the saving of sound tooth structure and the safeguarding of the long-term stability of the restorations are key to success. Depending on the aesthetic expectations of the patient, veneers made of zirconia or lithium disilicate, produced with a minimal vestibular cutback and finished using the micro-layering technique, are a great option. A prime example of an innovative porcelain system specifically developed for this technique is CERABIEN™ MiLai (Kuraray Noritake Dental Inc.). It includes a collection of internal stains and porcelains that fire at just 740 °C. With this low firing temperature and a coefficient of thermal expansion between 9.5~11.0×10-6/K (50 °C – 500 °C), this product is ideal for use with lithium disilicate and zirconia. In addition, it offers impressive aesthetic capabilities: Depending on the specific needs of each case, users can adjust the level of complexity and number of bakes.

CASE EXAMPLE

In the present case of a young female patient with hypomineralisation, it was decided to follow a straightforward approach to restore the maxillary teeth for the time being. For this purpose, we produced a wax-up and transferred it into the patient’s mouth in the form of a mock-up. Following guided tooth structure removal trough this mock-up, an impression was taken. The restorations were designed in full contour, pressed using lithium disilicate-based press ingots (Amber® Press LTW3, HASS Corp.) and cut back slightly in the vestibular area (reduction: 0.3 mm). The selected micro-layering system was applied according to the internal stain technique. The following CERABIEN™ MiLai Internal Stains were used: A little Red in the cervical, and Mamelon 2, Incisal Blue 1 and White in the incisal third. What followed was build-up with CERABIEN™ MiLai Porcelains Tx incisally and LTx proximally; some whitish lines were created with Value Liner 1. Then, I applied a mixture of E2 and ELT1 in the middle and LT1 in the cervical area. After the bake, the restorations were treated with green stones, sandpaper and rubber wheels to pre polish the surface. After glazing with CERABIEN™ ZR FC Paste Stain Clear Glaze, final polishing was carried out.

The whole treatment procedure including tooth preparation, shade determination, veneer production and adhesive cementation is illustrated below.

Fig. 1. Portrait of the patient prior to treatment.

Fig. 2. Enamel defects in the maxilla and mandible.

Fig. 3. Initial clinical situation in the maxilla with whitish-brown discolouration and composite restorations in need of replacement.

Fig. 4. Mock-up in the patient’s mouth.

Fig. 5. Labial reduction through the mock-up: The depth of tooth preparation is controlled by using a depth guide and by marking the created depth grooves with a colour marker.

Fig. 6. Silicon index used to check the space created for the veneers.

Fig. 7. Prepared teeth ready for impression taking and temporization.

Fig. 8. Shade determination for the veneers.

Fig. 9. Pressed lithium-disilicate restorations on the model.

Fig. 10. Appearance of the restorations after internal staining.

Fig. 11. Appearance of the teeth after build-up with CERABIEN™ MiLai Porcelain.

Fig. 12. Final restorations on the model.

Fig. 13. Adhesive cementation procedure carried out for two teeth at once: Isolated teeth and a perfectly dry working field.

Fig. 14. Etching of the tooth structure with phosphoric etchant (K-ETCHANT Syringe, Kuraray Noritake Dental Inc.).

Fig. 15. PANAVIA™ V5 Tooth Primer (Kuraray Noritake Dental Inc.) applied to the etched tooth surfaces.

Fig. 16. Veneers – pre-treated with hydrofluoric acid and CLEARFIL™ Ceramic Primer Plus – filled with PANAVIA™ V5 Paste (Both from Kuraray Noritake Dental Inc.) and placed in the patient’s mouth.

Fig. 17. Restorations after excess removal.

Fig. 18. All eight restorations in place.

Fig. 19. Treatment outcome after two weeks.

Fig. 20. Portrait of the patient taken two weeks after treatment.

CONCLUSION

Repeated dental treatment, increasing invasiveness of the measures, often resulting in early tooth loss: To break the vicious cycle in young patients with enamel defects, it is important to carefully evaluate the treatment need and select the appropriate solutions. As dental technicians, we can contribute to long-term treatment success by using high quality materials and production techniques that allow us to create restorations that last.

The presented material combination and the micro-layering technique are very well suited as they offer the required mechanical and optical properties for high aesthetics and durability. Plus, the risk of complications is low due to the high biocompatibility and the layer of porcelain limited to non-load-bearing areas.

Dental technicians:

ANDREAS CHATZIMPATZAKIS

Andreas graduated from the Dental Technology Institute (TEI) of Athens in 1999. During his studies he followed a program at the Helsinki Polytechnic Department of Dental Technique, where he trained on implant superstructures and all ceramic prosthetic restorations. As of 2000, he is running the ACH Dental Laboratory in Athens, Greece, specialized on refractory veneers, zirconia and long span implant prosthesis. In 2017 Andreas visited Japan where he trained under the guidance of Hitoshi Aoshima, Naoto Yuasa and Kazunabu Yamanda and become International Trainer for Kuraray Noritake Dental Inc..

MANOUSOS PISSADAKIS

Dr. Manousos Pissadakis is a graduate of the National Kapodistrian University Dental School, Athens, Greece. He completed the Master of Science curriculum in Prosthodontics at the School of Dentistry of the Aristotle University of Thessaloniki, Greece. He also holds the ITI Certificate in Implant Dentistry – Foundation and Intermediate Level (ITI Curriculum, ITI section Greece and Cyprus). He has presented at numerous prestigious international conferences, focusing on subjects such as aesthetics, implant dentistry and prosthodontics.

ACHIEVE CONSISTENT, NATURAL-LOOKING RESTORATIONS WITH CONFIDENCE

Shade selection is one of the most critical steps in restorative dentistry — and one of the most challenging. The KATANA™ Zirconia Shade Selection Guide provides practical, evidence-based recommendations to help clinicians and technicians achieve predictable, lifelike results every time.

Inside, you’ll find clear guidance on how abutment color, restoration thickness, milling and sintering conditions, and finishing methods influence the final shade outcome. Backed by Kuraray Noritake Dental’s expertise, this guide is designed to simplify your decision-making, minimize remakes, and support optimal aesthetics across different workflows.

Download now and equip your practice or lab with proven strategies for shade selection success.

VI AVLIVAR MYTERNA OM HÖGHÅLLFASTHETSKERAMER INOM TANDVÅRDEN

Kronor, broar, delproteser: När det kommer till att ersätta eller laga en individs tänder med hjälp av fast protetik står valet ofta mellan keramer med högre hållfasthet - litiumdisilikat och zirkonia. Förr gjorde den högre estetiska potentialen hos de silikatbaserade keramerna att de var särskilt lämpade för entandsersättningar, medan höghållfasthetsalternativet zirkonia oftast användes för broar och underkontruktioner. Tack vare den ständiga utvecklingen och förfiningen av dentala keramer och adhesiv teknik har saker och ting förändrats. Många av de ursprungliga begränsningarna gäller inte längre och nya möjligheter öppnar sig för användare i dentalbranschen.

I följande text kommer vi att ta itu med några särskilt seglivade föreställningar som ännu lever kvar gällande användningen av zirkonia och litiumdisilikat i tandvården. I detta sammanhang kommer du att få en uppdatering om vad som är möjligt att åstadkomma med materialen nuförtiden samt en vägledning i hur och när de kan användas.

1. ZIRKONIA ÄR ESTETISKT UNDERLÄGSET LITIUMDISILIKAT

Det första zirkoniamaterialet som användes inom tandvården var opakvitt. Därför användes det enbart för underkonstruktioner. För att skapa estetiskt tilltalande ersättningar behövdes ett relativt tjockt ytskikt av porslin. Bland senare generationers zirkonia finns dock varianter med mycket hög translucens och flerskiktad färgstruktur. Dessa varianter möjliggör enklare finisheringstekniker, som mikroskiktning eller påmålning. KATANA™ Zirconia UTML (Kuraray Noritake Dental Inc.) är till exempel ett av de mest translucenta zirkoniamaterialen på marknaden. Beroende på mätmetod har materialet samma, eller bara något lägre, translucens än litiumdisilikat (IPS e.max. CAD LT, Ivoclar Vivadent)1-4. Eftersträvade och naturliga resultat uppnås när ljus når, och reflekteras av den underliggande tandstrukturen. På så sätt kan naturliga ersättningar framställas i ett effektivt och automatiserat arbetsflöde.

SLUTSATS

Beroende på vilken typ av zirkonia respektive litiumdisilikat som används har båda materialen liknande estetiska egenskaper. Det mest högtranslucenta zirkoniamaterialet är dock starkare än det mest hållfasta litiumdisilikatmaterialet som finns att tillgå. Materialvalet ska därför baseras på andra kriterier som till exempel preparationens djup.

2. ZIRKONIABASERADE ERSÄTTNINGAR ÄR SVAGARE ÄN LITIUMDISILIKATBASERADE PÅ GRUND AV ATT DE KRÄVER PORSLINSSKITNING.

Det här antagandet stämmer när det gäller den förstagenerationens zirkonia. För modena zirkoniamaterial med hög translucens och flerskiktad färgstruktur ser det annorlunda ut. De senare lämpar sig utmärkt för produktion av monolitiska ersättningar eller för ersättningar med en minimal vestibulär cut-back och mikroskiktning med ytporslin. Med de ocklusala kontakterna i ren (polerad eller glaserad) zirkonia, är dessa ersättningar starkare än monolitiska ersättningar av litiumdisilikat eftersom risken för chipping är minimerad. Faktum är att även den svagaste zirkona har signifikant högre böjhållfasthet än litiumdisilikat (IPS e.max CAD LT, Ivoclar Vivadent)2,3. Tack vare den goda kantstabiliteten efter fräsning blir ersättningarna också väldigt hållbara, en gynnsam egenskap för långvarigt lyckande.

SAMMANFATTNING

Böjhållfastheten för zirkonia är generellt högre än för litiumdisilikat (800 till 1200 Mpa för zirkonia jämfört med 360 till 460 MPa för litiumdisilikat) och tack vare den förbättrade estetiska potentialen för de material som finns på marknaden behövs det inte längre ett heltäckande porslinsskikt. Således är zirkoniaersättningar vanligtvis väldigt starka och hållbara.

3. DET ÄR SVÅRARE ATT FINISHERA ZIRKONIAERSÄTTNINGAR ÄN ATT FINISHERA ERSÄTTNINGAR AV LITIUMDISILIKAT

When using modern, aesthetic zirconia materials, finishing techniques are quite similar. The most popular technique for both, high-translucency zirconia and lithium disilicate, is micro-layering. Based on a full-contour restoration design and a subsequent cutback limited to the vestibular area, a micro-layer of porcelain (often a specific porcelain line-up developed for micro-layering) is applied. With CERABIEN™ MiLai from Kuraray Noritake Dental Inc., the standard procedure consists of internal staining, the application of luster porcelains and final glazing. Fewer layers and fewer bakes are required compared to full porcelain layering. However, aesthetic zirconia can also be used for the production of monolithic restorations, which are characterized with paste stains and glazed.

Vid användning av moderna, estetiska zirkoniamaterial är finisheringsteknikerna ungefär desamma. Den vanligaste tekniken för både högtranslucent zirkonia och litiumdisilikat är mikroskiktning. Designen bygger på en fullanatomisk design med en cutback, begränsad till det vestibulära området, där ett mikroskiktat porslin (vanligtvis ett porslin speciellt framtaget för mikroskiktning) appliceras. Med CERABIEN™ MiLai från Kuraray Noritake Dental Inc. är standardförfarandet användning av internal stains, applicering av lysterporslin och en slutbränning. Färre skikt och färre bränningar krävs än vid traditionell porslinsuppbyggnad. Estetisk zirkonia kan också användas för framställning av monolitiska ersättningar som karaktäriseras med hjälp av pastafärger och glasering.

SLUTSATS

Modern zirkonia med monolitisk design eller en med minimal cutback är ett alternativ. Att finishera zirkonia är precis lika enkelt som att finishera litiumdisilikat. Tekniken avgörs av vilket resultat man eftersträvar.

4. ZIRKONIABASERADE ERSÄTTNINGAR ÄR MER INVASIVA ÄN DE SOM FRAMSTÄLLS AV LITIUMDISILIKAT

Den här föreställningen bygger på antagandet att zirkonia kräver ett tjockt lager ytporslin för att fungera estetiskt. Så är dock inte fallet; det är möjligt att uppnå fantastiska resultat med monolitisk design eller med mikroskiktning. Zirkonia som restorativt material fungerar utmärkt vid en minimalinvasiv preparationsdesign. Tack vare en jämförelsevis hög hållfasthet även för de högtranslucenta varianterna kan godset hållas tunt (0,4 mm för fasader av KATANA™ Zirkonia UTML eller STML och 0,5 mm för posteriora kronor av KATANA™ Zirconia HTML Plus)*. Det ger utrymme för en defektorienterad preparationsteknik.

*Generellt avgörs minsta godstjocklek av slutprodukten och av indikationen.

SLUTSATS

Beroende på vilken sorts zirkonia och vilken finisheringsmetod som används kan zirkonia användas för minimalinvasiva ersättningar.

5. PÅ GRUND AV MATERIALETS HÅRDHET SKADAR MONOLITISK ZIRKONIA ANTAGONERANDE TÄNDER.

När tillverkare av zirkonia för dentalt bruk började förespråka användning av monolitisk zirkonia visade in-vitrostuder ganska snart att det inte är materialets hårdhet, utan snarare ytråheten är som är avgörande för hur skadligt materialet är för antagonerande tänder5-8. Dessa studier visade att en välpolerad zirkoniayta behåller sin jämna yta; den är överlägsen andra material, inklusive litiumdisilikat, när det kommer till både eget slitage såväl som slitage på antagonerande tänder6-8. En glaserad yta - till skillnad från den polerade - tenderar att nötas bort över tid och det är tydligt att en perfekt polerad yta är avgörande för vävnadsvänlighet över tid. Resultaten in-vitro bekräftades också in-vivo9,10. Enligt den senaste paraplystudien i ämnet ger polerad monolitisk zirkonia mindre emaljslitage på antagonerande tänder än testad metallkeramik, fältspatsporslin och litiumdisilikat10.

SLUTSATS

Förutsatt att ytan är slät är monolitiska zirkoniumoxidrestaurationer snälla mot den motstående tanden och med tiden kan man förvänta sig att emaljslitaget på den motstående tanden kommer att ligga på en liknande nivå som det gjort naturligt.

6. DET ÄR OMÖJLIGT ATT ADHESIVCEMENTERA ZIRKONIA.

När oxidkeramik som zirkonia bearbetas och förbehandlas på samma sätt som kiselbaserade keramer t.ex. litiumdisilikat, blir den erhållna bindningsstyrkan lägre. Genom att använda rätt protokoll för förbehandlingen är det dock möjligt att etablera en stark och hållbar kemisk bindning mellan tand och zirkonia. Annars hade det till exempe linte varit möjligt att cementera entandsstödda resinbondade Marylandbroar av höghållfasthetszirkonia (3T-TZP). Designen på dessa broar är i hög grad ickeretinerande varför kvaliteten på bindingen är helt avgörande. En sådan bindningsstyrka skapas genom att cementeringsytan på zirkoniavingen blästras med aluminiumoxid (50 μm) och lågt tryck (ungefär 2 till 2,5 bar) efter inprovning 11,12, följt av rengöring i ultraljudsbad, användning av primer innehållande 10-MDP13 och användning av ett högkvalitativt resincement som PANAVIA™ V5 (Kuraray Noritake Dental Inc.)14. Genom att användadet här protokollet tillsammans med nyss nämndaresincement har man uppnått tioårig överlevnad och över 90-procentig lyckandefrekvens15. Protokollet ovan är överenstämmande med APC-konceptet som rekommenderas av Dr. Markus Blatz: (A) blästring med luftburna partiklar (P) zirkoniaprimer och (C) användning av adhesivt resinkompositcement16.

SLUTSATS

Genom att använda ett lämpligt protokoll bestånde av blästring med liten kornstorlek efter inprovning och ett högkvalitativt adhesivt cement med MDP-primers kan man etablera en stark och hållbar kemisk bindning.

7. ZIRKONIA ÄR INTE ETT LÄMPLIGT MATERIAL ATT ANVÄNDA NÄR MAN HAR BRÅTTOM EFTERSOM ERSÄTTNINGEN MÅSTE SINTRAS EFTER FRÄSNING.

Genom att använda zirkoniavarianter som lämpar sig för snabbsintring kan mindre ersättningar produceras på mycket kort tid. Entandsersättningar och små broar (upp till tre led) som framställts av till exempel KATANA™ Zirkonia Multi-Layered kan snabbsintras på 54 minuter, förutsatt att rätt sintringsugn används. Det kortar ner produktionstiden avsevärt och är ett utmärkt alternativ när det är bråttom. Om arbetet ska göras chairside och samma dag är KATANA™ Zirkonia Block ett utmärkt val. Materialet har samma optiska och mekaniska egenskaper som KATANA™ Zirconia STML och har en sintringstid på endast 18 minuter.

SLUTSATS

Genom att använda lämpliga zirkoniamaterial och rätt utrusning är produktionstiden för zirkoniaersättningar inte längre ett hinder om du har bråttom.

8. ALLA HÖGHÅLLFASTHETSKERAMER HAR LIKNANDE ANVÄNDNINGSOMRÅDE

Faktum är att indikationerna vaierar beroende på materialens böjhållfasthet och brottseghet. Medan användningen av litiumdisilikat är begränsat till framställning av singelersättningar och små broar kan zirkonia användas för fler indikationer, där de höghållfasta varianterna till och med kan användas för framställning av långa brospann. De mest mångsidiga varianterna av zirkonia är de som har en flexibel styrkegradient - som KATANA™ Zirconia YML. Det är ett material som har mycket translucens i emaljskiktet och hög hållfasthet i dentinskikten. Därför är materialet mycket väl lämpat för framställning av både entandsersättningar såväl som komplexa strukturer som broar med långa spann - beroende på var i disken ersättningen placeras.

SLUTSATS

Zirkonia har ett bredare användningsområde än litiumdisilikat. Genom att välja de varianter som har flerskiktad struktur med gradient för böjhållfasthet är det fullt möjligt att använda zirkonia vid - i princip - alla indikationer. Andra typer av zirkonia lämpar sig bättre för specifika behov (för estetiskt krävande fall används de mest translucenta varianterna och för komplexa konstruktioner med långa spann används de sorter som har högst hållfasthet).

ZIRKONIA ETT VERKLIGT ALLROUNDMATERIAL

Moderna zirkoniamaterial för dentalt bruk är högkvalitativa material, med väl avvägda optiska och mekaniska egenskaper, som lämpar sig för en lång rad indikationer. Som användare av zirkonia kan du välja att använda ett och samma material med böjhållfasthetsgradient för framställning av praktiskt taget alla ersättningar eller, om du föredrar det, välja olika material beroende på de specifika kraven i varje enskilt fall. Du har friheten att välja finisheringsteknik - från traditionell porslinsskiktning till enbart polering om du siktar på minimalinvasiv behandling. Det senare är möjligt tack vare beprövade protokoll som ger en stabil och hållbar bindning till zirkonia. För höga kvalitetskrav på sina material och resultat är det värt att prova KATANA™ Zirkonia Multi-Layered. Råmaterialet har en unik materialsammansättning, pulvret framställs in-house i Japan och ämnena produceras under noggrannt kontrollerade förhållanden, vilket ger ett homogent och hårt packat dentalt material med perfekt passform, hög hållfasthet och överlägsen kantstabilitet. alla med

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