Case by Andreas Chatzimpatzakis

A CONCEPT EVEN FOR AESTHETICALLY DEMANDING CASES

The micro-layering technique is regarded as a more efficient, streamlined approach used as an alternative for full porcelain layering. It requires aesthetic, high-strength ceramics like lithium disilicate or zirconia as a base and – ideally – a set of porcelains specifically designed for reduced layer thicknesses that allows users to focus on imitating the characteristics of enamel. A high-quality example is CERABIEN™ MiLai (Kuraray Noritake Dental Inc.). Consisting of a set of internal stains and porcelains with a firing temperature of just 740 °C and a coefficient of thermal expansion in the range of 9.5~11.0×10-6/K (50 °C – 500 °C), this product works well on lithium disilicate and zirconia.

Its aesthetic potential is surprisingly high: Depending on case-specific requirements, users are given the choice between maximum efficiency using a single-bake technique and maximum aesthetics achieved with more complex layering. The latter option is demonstrated below using the example of six maxillary anterior veneers.

Fig. 1. Lithium disilicate frameworks (Amber Press) on the model.

Fig. 2. CERABIEN™ MiLai Value Liner 1 applied to the framework. This porcelain is typically used on lithium disilicate for wash baking.

Fig. 3. First build-up with CERABIEN™ MiLai CCV2 in the cervical section, …

Fig. 4. … Value Liner 2, …

Fig. 5. … Creamy Enamel in the middle area …

Fig. 6. … and Tx used to add ultimate translucency.

Fig. 7. Appearance of the restorations after the first bake.

Fig. 8. Outcome of the internal staining procedure.

Fig. 9. Application of CERABIEN™ MiLai LT1 for a standard translucency and opalescence effect, …

Fig. 10. … E2, …

Fig. 11. … a mixture of E2 and ELT1 (mixing ratio: 50:50) for translucency and brightness and along the marginal ridges, …

Fig. 12. … Tx mixed with Royal Blue (mixing ratio 70:30) for a blueish translucency in the incisal area…

Fig. 13. … as well as a final layer of LTx to add ultimate translucency and opalescence to the whole enamel surface.

Fig. 14. Outcome of the third bake.

Fig. 15. Cutback for the final layer of porcelain.

Fig. 16. Final layer of CERABIEN™ MiLai added to the central and lateral incisors for translucency.

Fig. 17. Situation after the fourth bake, grinding and use of a rubber polisher.

Fig. 18. Outcome of the fifth bake (self-glaze).

Fig. 19. Beauty shots …

Fig. 20. … of the restorations …

Fig. 21. … on the model.

TRULY BEAUTIFUL OUTCOMES POSSIBLE

This case example reveals that CERABIEN™ MiLai is much more than just a maximum-efficiency solution: With the current line-up of porcelains and internal stains, truly beautiful restorations can be produced. Hence, users are given high flexibility regarding not only the high-strength framework material they prefer, but also the effort and time they would like to invest. This makes CERABIEN™ MiLai a versatile porcelain system that meets many needs and covers a wide range of applications in the dental laboratory.

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..

Case by Kostia Vyshamirski, DT

KATANA™ Zirconia YML AND CERABIEN™ MiLai

Virtually every patient in need of restorative treatment desires functional restorations with an aesthetic appearance. However, the individual expectations and needs may be very different depending on the clinical situation (state of the natural tooth structure, parafunctional behaviour, periodontal health etc.), the patient’s financial resources and personal preferences. A versatile material combination fulfilling many different needs and desires is KATANA™ Zirconia YML finished using micro-layering with the new CERABIEN™ MiLai (both Kuraray Noritake Dental Inc.).

This system supports low invasive preparations due to a favourable minimum wall thickness of the merely monolithic multi-layered zirconium oxide prosthesis and a minimal thickness of the porcelain layer in the aesthetic zone. Moreover, the high strength zirconium oxide prosthesis combined with only a very thin layer of porcelains makes this technique extremely useful in patients with parafunctional habits like bruxism. Last but not least, consisting of a carefully compiled selection of internal stains and porcelain shades, CERABIEN™ MiLai supports the creation of individual 3D shade effects that mimic those of natural teeth even when space is limited. The following case example reveals how this is possible.

INITIAL SITUATION

The patient presented with concerns related to both function and appearance. During the diagnostic phase, it was determined that increasing the vertical dimension of occlusion (VDO) and creating a wax-up in the new jaw position would be necessary to improve both the occlusion and the aesthetic appearance of the smile.

Fig. 1. Intraoral scan of the maxillary teeth revealing severe tooth wear.

Fig. 2. Intraoral scan of both jaws confirming the need for an increase of the VDO.

Fig. 3. Intraoral scan: Occlusal view of the maxillary teeth.

TREATMENT PLANNING AND COMPUTER-AIDED DESIGN

Following the approval of the wax-up, the treatment plan was created. It consisted of restoring the four anterior incisors with zirconia crowns and performing direct composite restorations on the posterior and lower teeth. To conserve as much of the healthy tooth structure as possible, the space created was aligned to the required wall thickness of the planned restoration (framework + micro-layer of porcelain in the vestibular areas only). Following an aesthetic analysis, the crowns were designed with a minimal vestibular cutback. This was due to the patient’s functional problems, which would increase the chipping risk in case of using a more heavy cutback design with a thicker, more conventional porcelain layer. KATANA™ Zirconia YML offers exceptional aesthetics, requiring only a 0.3 mm reduction for the porcelain to achieve natural results. Therefore, it was the logical material choice for this specific case.

Fig. 4. Minimally invasive preparations for the crowns.

Fig. 5. Occlusal view of the preparations.

Fig. 6. Aesthetic analysis – a crucial step for achieving the desired new smile.

Fig. 7. Frontal view of the crowns in their final cutback design.

Fig. 8. Lateral view of the crowns in the CAD software.

CROWN PRODUCTION

Immediately after milling, the zirconia surface was treated with effect liquids. This kind of pre-sintered characterization helps enhance the characteristics of zirconia restorations. In the presented case, orange stain was applied to the cervical area, while a blue stain was used at the incisal edge. In addition, a white opaque liquid was applied to the inner surface of the central zirconia crowns to block out any discolouration from the underlying tooth structure. Following final sintering, the vestibular layer of porcelain was built up with CERABIEN™ MiLai using a combination of internal stains and porcelain micro-layering. After morphological adjustments and surface polishing, the restorations were completed by applying CERABIEN™ ZR FC Paste Stain and Glaze. Final polishing was then performed to enhance the natural appearance of the surfaces.

Fig. 9. Effect liquids applied to the cervical and incisal areas of the crowns.

Fig. 10. Treatment of the central incisor crowns’ inner surfaces.

Fig. 11. KATANA™ Zirconia YML framework after sintering.

Fig. 12. CERABIEN™ MiLai Internal Stains and Porcelains.

Fig. 13. Prepared vestibular surfaces ready for application of the internal stains.

Fig. 14. Application of 0.2-0.3 mm layers of CERABIEN™ MiLai porcelain: CCV2 for the cervical area, LT1 – Creamy Enamel for the main body and luster, LTX at the incisal edge.

Fig. 15. Frontal view of the final restorations on the model.

Fig. 16. Lateral view of the final restorations on the model.

Fig. 17. Polished and glazed palatal surfaces of the crowns.

FINAL OUTCOME

The finalized restorations showcase great details, crafted with CERABIEN™ MiLai internal stains and porcelains. The result are natural-looking restorations. An additional benefit of using zirconia as a restorative material is its excellent compatibility, which is evident in the healthy gingival conditions.

Fig. 18. Restorations in place.

Fig. 19. Natural-looking restorations in the patient’s mouth.

Dental Technician:

KOSTIA VYSHAMIRSKI

DT Kostia Vyshamirski, Riga, Latvia

After earning his Dental Technician Certificate from the Medical College in Minsk, Belarus, in 2014, Kostia began his career as a dental technician, focusing on aesthetic clinical cases that integrate the latest digital and manual technologies. Moving to Riga, Latvia, in 2015 greatly expanded his professional opportunities.

With over a decade of experience, Kanstantsin Vyshamirski now conducts courses, lectures, and seminars worldwide. He is a member of the DTG (Dental Technician Guild), a professional group of dental technicians based in the USA, and an invited guest of the AAED (American Academy of Esthetic Dentistry), an exclusive, invitation-only organization.

Operating his own lab in Riga, Latvia, Kanstantsin specializes in aesthetic prosthetic porcelain work and is an experienced, passionate user of KATANA™ Zirconia and Noritake porcelains.

CERABIEN™ MiLai in Daily Use

A tooth with crack lines, a characteristic round shape, age-related changes, or medication-induced discoloration — there’s no one-size-fits-all solution when it comes to all-ceramic anterior restorations, even when the porcelain system and production technique are defined.

To support technicians who wish to simplify their layering workflow using the micro-layering technique and CERABIEN™ MiLai — whether just getting started or looking to refine their process — we’ve collaborated with DT Dumitru Leahu to create a Chroma Map Catalogue featuring seven typical anterior restoration scenarios.

Each case example includes a detailed screenshot of the framework design, chroma maps outlining the planned steps, images of internal staining and micro-layering procedures, and the final restoration on the model. You’ll also find essential information about the selected framework material, target shade, and other relevant details.

We invite you to use the CERABIEN™ MiLai Catalogue as a step-by-step guide to success or simply as inspiration for individual cases. It offers a fast track to understanding the material’s optical properties and will make planning your next micro-layering case more intuitive. No need to start from scratch — instead, adapt what’s already there and gradually develop your own maps and techniques.

Interested in the CERABIEN™ MiLai Chroma Map Catalogue?

Download it here!

Interview with Ghaith Alousi, DT

He inspires dental technicians with his passion and creativity as a course instructor, and with Nature Style, he has developed a well-conceived concept for the creation of lifelike anterior restorations. We are talking about Ghaith Alousi, a dental technician based in Wiesbaden, Germany. While course participants usually attend his training courses eager to learn from his experience and technical knowledge, they often return to their laboratories bursting with positive energy, truly inspired and deeply motivated to break new ground.

Ghaith Alousi, what is the dental technician’s primary mission?

In my eyes, dental technicians are not artists; rather, their primary mission is to replicate nature – both functionally and aesthetically. Every tooth, like every patient, is as unique as a fingerprint. To recreate a natural tooth as accurately as possible, we must listen, observe, and understand. To truly perceive the details that matter, however, we need to know where to focus our attention. In my opinion, the three golden keys to anterior aesthetics are paramount: balanced translucency and opacity, morphology, and surface texture.

What about colour?

While colour is undoubtedly a crucial aspect, I believe it is often overemphasized. Many dental technicians focused on aesthetic anterior restorations find themselves preoccupied solely with colour. However, natural teeth – the model we aim to replicate – embody far more than just a blend of hues.

First and foremost, we must understand how light interacts with teeth. They diffuse light in a unique manner, with different layers of enamel and dentin each possessing distinct optical properties. Additionally, the individual shape and surface texture of a tooth significantly affect the perceived attractiveness of a patient’s smile and overall facial appearance. Therefore, I have learned to prioritize these elements, observing nature closely and striving to comprehend what I see before embarking on the replication process.

Fig. 1. Light-optical properties of natural teeth imitated with KATANA™ Zirconia YML, Esthetic Colorant and CERABIEN™ ZR porcelain (Kuraray Noritake Dental Inc.).

Let’s take a brief look at each of the three golden keys, starting with the light-optical properties.

To truly grasp how light interacts with natural teeth, we must first examine their structure. Natural teeth consist of various layers, each displaying unique light-optical behaviours, with enamel and dentin being the most significant. Upon closely observing the dentin core of a tooth, we realize it is not only responsible for the tooth’s fundamental colour but also exhibits distinct opacity – it does not transmit light; instead, it reflects and absorbs it. In contrast, enamel presents a different scenario: its thickness varies with factors such as the patient’s age, but it is consistently highly translucent. This translucency allows a portion of light to pass through, with only a minimal amount reflected or absorbed.

Once we have a solid understanding of the natural light dynamics inherent in a patient’s teeth, the next step is to replicate these characteristics using selected materials. Thus, comprehending the light-optical properties of available materials, choosing them wisely, and applying them effectively are crucial milestones on the path to success.

What about morphology?

I firmly believe that mastering morphology – the replication of natural tooth shapes – can significantly impact a dental technician’s work. The growing popularity of carving workshops in Japan and other parts of the world reinforces this idea. Aspiring technicians avoid using standard dental libraries that produce generic smiles for their patients. Rather than traveling long distances to attend workshops and build our own mental library of tooth shapes, we can explore the intricacies of form and shape right in our dental laboratories through careful observation and consistent practice. Some technicians capture images of the teeth they encounter, while others concentrate on their own teeth or those of colleagues and patients. This approach allows for the replication of shapes using materials like wax or ceramics. By honing our observation and replication skills, we expand our personal knowledge base. This commitment to detail fosters true mastery – a continuous journey toward perfection.

Fig. 2. Example of a natural surface texture reproduced with CERABIEN™ MiLai and different diamond burs, stones and rubber polishers.

Is surface texture similarly important?

Absolutely. The surface texture of a restoration, even more than its hue, must precisely match that of surrounding or opposing teeth to achieve a natural appearance. To accomplish this, we must understand and replicate the intricate interplay of micro- and macrotextures that create a tooth’s natural look. Macrotexture encompasses the tooth’s overall surface characteristics, including varying concavities, convexities, line angles, and vertical V-shaped grooves. In contrast, microtexture focuses on finer details, such as growth lines (striae of Retzius), perikymata, small grooves, and the degree of surface gloss. A keen eye is essential to replicate every surface detail harmoniously so that light interacts optimally, creating reflections, shadows, and highlights exactly where they are needed.

Fig. 3. Large tooth created with CERABIEN™ ZR.

How do you practice?

To practice replicating surface texture and morphology, I typically start with enlarged model teeth, first using wax and later transitioning to my preferred dental materials and instruments. The increased size of the working base allows for easier detection, reproduction, and assessment of relevant morphology and surface details compared to original-sized tooth forms. This enlargement also facilitates the evaluation of light-optical properties. For the final assessment, I often apply silver or gold powder to the surface of the model tooth, which highlights even the finest surface nuances. This method makes it easy to identify areas that are well-executed and those that may need improvement.

Fig. 4. Gold powder applied to anterior restorations …

Once I achieve a high level of quality with the enlarged model teeth, I transfer the acquired skills to real-life applications by working with actual-sized teeth. This practice framework allows me to continuously enhance my basic skills. Moreover, each time I start working with a new instrument or material, this approach streamlines the initial learning curve, quickly elevating my performance to a high standard.

Fig. 5. … to evaluate their shape and surface texture.

What are your preferred material combinations for different indications / needs?

For cases with highest aesthetic demands, CERABIEN™ ZR (Kuraray Noritake Dental Inc.) is my favourite porcelain system. I This system can be utilized either as a standalone solution for producing veneers using the refractory die technique or in conjunction with a zirconia framework – typically crafted from KATANA™ Zirconia variants such as KATANA™ Zirconia UTML, STML, HTML Plus, or YML (also from Kuraray Noritake Dental Inc.) – in a full layering approach.

I frequently employ this combination to produce single crowns in the anterior region, selecting the framework material based on the colour of the underlying tooth structure and the appearance of adjacent teeth. An alternative approach is layering with CERABIEN™ MiLai, which consists of internal stains and porcelains compatible with zirconia and lithium disilicate. I prefer to combine this system with the previously mentioned zirconia variants or with lithium disilicate, predominantly using the porcelain to replicate enamel. Sometimes, I employ the system’s internal stains to enhance the result with natural colour effects.

Apart from observing closely, selecting appropriate materials and copying carefully, are there any additional factors decisive for great treatment outcomes from the technician’s point of view?

To my mind, there are two additional essential factors: Proper interaction and communication within the restorative team and personal interaction with the patient. Especially in the highest aesthetic demand cases, meeting a patient in person is very important. They are usually invited to visit the dental laboratory twice, prior to treatment planning and for try-in. Nothing can replace personal interaction with them and a genuine impression of the initial situation. After all, we need to give them a sense of security and build trust, while analysing their character, facial characteristics, skin colour and more allows us to produce perfectly matching restorations.

Fig. 6. Full layering approach with CERABIEN™ ZR on a KATANA™ Zirconia YML framework.

And the restorative team?

We share a common goal: to fulfil the desires of our patients. I firmly believe that achieving this requires a united effort from the entire team. Collaboration hinges on appreciative and open communication at all levels and demands absolute honesty. Furthermore, everyone involved must be committed to continuously developing their skills.

I hold high expectations not only for my own work but also for the contributions of each dentist in our team. After all, their work forms the foundation of what I do. For example, when a dentist invests in an intraoral scanner and starts providing digital records, it is my responsibility to verify whether the quality of those scans meets our high standards. If I notice that the quality could be improved, I approach the situation with respect, offering constructive feedback and guidance to help them deliver quality scans consistently. This is crucial, as high-quality scans are the prerequisite for creating outstanding restorations.

In my experience, most dental practitioners appreciate this kind of honest and supportive communication. It creates an environment where we can all grow and evolve together.

Do you have any additional comments?

Be authentic, strive for excellence, and approach each day as an exhilarating opportunity. Courage plays a vital role, too – the readiness to venture beyond your usual routines, such as experimenting with different shades to discover new possibilities, fosters growth. Even if the outcome does not meet your expectations, there is valuable insight to gain from the experience that can guide you in the future. To reach new horizons, be open to exploring uncharted paths.

Dentist:

GHAITH ALOUSI

Ghaith Alousi, born in 1994, successfully completed his training as a master dental technician in 2013 in Damascus, Syria, where he gained initial experience in a dental laboratory. From 2014 to 2016, he worked independently in Damascus, using his craftsmanship to produce ceramic work such as frameworks, veneers, crowns and bridges, and implant-based restorations. He also engaged in shade determination, photography, and CAD/CAM technology.

He came to Germany in 2016 and quickly felt at home. Through further education, he has continuously expanded his knowledge and skills and is currently working as a dental technician in Wiesbaden. To achieve the best possible results, Ghaith Alousi places great value on collaboration with dentists and personal contact with patients.

Case by DT Tomas Forejtek, Forejtek Dental Lab and Dr Ladislav Gregor, Sorriso Dental Clinic

In prosthodontics, assessing the individual needs and expectations of every patient is a crucial factor on the road to success. When it comes to producing fixed dental prostheses, the art is in tailoring the material combination, framework design and finishing concept precisely to the case-specific functional and aesthetic demands. In this context, the availability of high-performance evaluation tools and the freedom to choose between different variants of high-strength ceramics is worth gold.

CASE EXAMPLE

Take the case of a middle-aged female patient: She presented with very unsatisfactory metal-ceramic crowns (Fig. 1) and asked for an aesthetic improvement of the situation. The crowns on her maxillary central incisors and the right lateral incisor clearly needed to be replaced not only for aesthetic, but also for functional reasons. As anterior interferences were present and orthodontic treatment was not an option, the decision was made to select a ceramic material with a particularly high strength – KATANA™ Zirconia HT (Kuraray Noritake Dental Inc.) – and to opt for a design that would support the incisal edge with zirconia. Consequently, porcelain layering (with CERABIEN™ ZR, Kuraray Noritake Dental Inc.) would be limited to the vestibular region. The laboratory procedure – including shade determination and reproduction with the aid of the eLAB® shade matching system* – is illustrated in Figures 2 to 9.

^{*The eLAB® system is a registered trademark of Sascha Hein. It is an independent tool for dental shade determination and communication and is not developed or distributed by Kuraray Noritake Dental Inc.}

Fig. 1. Initial clinical situation.

Fig. 2. Situation after removal of the existing crowns and preparation of the tooth structure for the planned all-ceramic restorations.

Fig. 3. Shade determination with the eLAB® system.

Fig. 4. Layering map for the use of CERABIEN™ ZR on all three crowns.

Fig. 5. Layering procedure: Shade verification.

Fig. 6. Try-in of the crowns to assess the fit and the shade match.

Fig. 7. Palatal view of the crowns on the model.

Fig. 8. Frontal view of the crowns on the model: A natural surface texture is obtained.

Fig. 9. Natural look of the restorations.

THE RESULTS

Fig. 10. Crowns after adhesive cementation with PANAVIA™ V5 (Kuraray Noritake Dental Inc.).

Fig. 11. Aesthetic treatment outcome.

A precise reproduction of the patient’s tooth shade, despite the challenging individual aesthetics.

THE KEY TO SUCCESS: INDIVIDUAL APPROACH, HIGH-QUALITY MATERIALS

The present case is a perfect example of an aesthetically and functionally challenging situation that needed an individual treatment approach. By taking into account the patient- and case-specific requirements and using our material-related knowledge wisely, it was possible to develop an adequate treatment plan. High-quality materials and a smartly selected design concept lay the foundation for long-term success. Valuable tools used during porcelain layering (specifically the eLAB® system) – on the other hand – paved the way for a precise reproduction of the patient’s tooth shade, despite the challenging individual aesthetics: The crowns were delivered on the first attempt.

Dental technicians:

LADISLAV GREGOR

Ladislav Gregor is a prosthodontist at Sorriso Dental Clinic in Brno, Czech Republic. A Masaryk University graduate (2005), he later served at the University of Geneva and earned both a Dr. Med. Dent. (Geneva) and a Ph.D. (ACTA Amsterdam). He has published extensively in adhesive and reconstructive dentistry, lectures internationally, is a certified CADE member, and serves on the Scientific Council of the Czech Dental Chamber.

TOMAS FOREJTEK

Tomas Forejtek is a dental technician in Brno specializing in aesthetic ceramic restorations. After graduating top of his class in 2001, he advanced to head of a leading dental laboratory and trained internationally with renowned mentors. In 2010, he opened his own lab, and since 2016 he has focused on single maxillary central incisor work with the eLAB protocol, becoming an official eLAB instructor in 2018.

BUSTING MYTHS AROUND HIGH-STRENGTH CERAMICS IN DENTISTRY

Crowns, bridges, partial restorations: When it comes to replacing or restoring an individual’s teeth with fixed dental prostheses, the choice is often between the high-strength ceramics - lithium disilicate and zirconia. Originally, the higher aesthetic potential of silicate ceramics made them particularly suitable for single tooth restorations, while the high-strength option zirconia was predominantly used for bridges and frameworks. Due to continuous improvements in the development of dental ceramics and adhesive technology, things have changed. Many of the original limitations and restrictions are no longer valid, and new opportunities arise for users in the dental setting.

In the following, we will address certain persisting myths about the use of zirconia and lithium disilicate in dentistry. In this context, you will receive an update on what is possible with the materials today and guidance on how and when to use them.

1. ZIRCONIA IS AESTHETICALLY INFERIOR TO LITHIUM DISILICATE

The original zirconia used in dentistry was whitish-opaque. Therefore, it was used as a framework material only. To create aesthetic restorations, it was necessary to apply a relatively thick layer of veneering porcelain. More recent generations of zirconia, however, include variants with a particularly high translucency and a multi-layered colour structure. These variants allow for less complex finishing techniques such as micro-layering or external staining. KATANA™ Zirconia UTML (Kuraray Noritake Dental Inc.), for example, is one of the most translucent zirconia materials on the dental market. Depending on the test method used, it offers a similar or only somewhat lower translucency compared to lithium disilicate (IPS e.max CAD LT, Ivoclar Vivadent)^1-4. The desired natural result is achieved as light reaches – and reflects – the underlying tooth structure. Consequently, true-to-life restorations can be produced in an efficient, highly automated workflow.

CONCLUSION

Depending on the variant of zirconia and lithium disilicate used, both materials offer similar aesthetic properties, while even the highest-translucency zirconia is stronger than the highest-strength lithium disilicate available. Material selection may therefore be based on other criteria such as preparation depth for example.

2. ZIRCONIA-BASED RESTORATIONS ARE WEAKER THAN LITHIUM DISILICATE-BASED ONES DUE TO THE NEED OF A PORCELAIN LAYER ON TOP OF ZIRCONIA

This assumption is true for the first generations of dental zirconia. For modern zirconia materials with a high translucency and multi-layered colour structure, however, the situation is different. They are suitable for the production of monolithic restorations or restorations with a minimal (vestibular) cutback and a micro-layer of porcelain. With occlusal contact areas made of plain (polished or glazed) zirconia, these restorations are stronger than monolithic lithium disilicate restorations, while the chipping risk is minimized. In fact, even the weakest zirconia offers a significantly higher flexural strength than lithium disilicate (IPS e.max CAD LT, Ivoclar Vivadent)^2,3. Thanks to the high edge stability of zirconia after milling, the restorations are also highly stable, a favourable property for long-term success.

CONCLUSION

The flexural strength of zirconia is generally higher than that of lithium disilicate (800 to 1,200 MPa for zirconia versus 360 to 460 MPa for lithium disilicate), and due to the improved aesthetic potential of the available materials, a full porcelain layer is no longer required. Hence, zirconia restorations are usually very strong and durable.

3. FINISHING OF ZIRCONIA RESTORATIONS IS MORE COMPLICATED THAN FINISHING OF LITHIUM DISILICATE RESTORATIONS

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.

CONCLUSION 

As a monolithic design or minimal cutback of restorations based on modern zirconia materials is an option, finishing of zirconia is just as easy as finishing of lithium disilicate restorations. The technique depends on the desired outcome.

4. ZIRCONIA-BASED RESTORATIONS ARE MORE INVASIVE THAN THOSE MADE OF LITHIUM DISILICATE

This myth is also based on the assumption that zirconia needs a thick porcelain layer on top to produce aesthetic results. Since this is not the case and great outcomes are possible with monolithic designs or micro-layering approaches, a minimally invasive preparation design is supported by the use of zirconia as a restorative material. Due to a comparatively high strength even of the high-translucency variants, the minimum wall thickness is quite low (e.g. 0.4 mm for veneers made of KATANA™ Zirconia UTML or STML and 0.5 mm for posterior crowns made of KATANA™ Zirconia HTML Plus)*. This allows for a defect-oriented tooth structure removal.

*In general, the minimum wall thickness depends on the product and the indication.

CONCLUSION 

Depending on the type of zirconia and the finishing method, zirconia supports the production of minimally invasive restorations.

5. DUE TO THEIR HARDNESS, MONOLITHIC ZIRCONIA RESTORATIONS HARM THE OPPOSING DENTITION

When manufacturers of dental zirconia started promoting the monolithic use of zirconia, in-vitro studies were soon available to prove that it is not the hardness of the material, but the smoothness of the surface that determines how kind or harmful a dental restoration is to the opposing dentition^5-8. According to those studies, well-polished zirconia surfaces maintained their smoothness and showed a superior self-wear and wear to the opposing tooth structure compared to other restorative materials including lithium dislilicate^6-8. As glaze - unlike the polished surface - tended to wear off over time, it was stressed that a perfectly polished restoration surface is essential for a wear-friendly long-term behaviour. The in-vitro study results were also confirmed in vivo^9,10. According to the latest umbrella review focusing on this topic, polished monolithic zirconia causes lower antagonist enamel wear than metal ceramics, feldspathic porcelains and lithium disilicate tested¹⁰.

CONCLUSION 

Provided that the surface is smooth, monolithic zirconia restorations are kind to the opposing natural tooth structure. Over time, the opposing enamel wear may be expected to be on a similar level as natural enamel wear.

6. ADHESIVE LUTING OF ZIRCONIA-BASED RESTORATIONS IS IMPOSSIBLE

When oxide ceramics like zirconia are processed and pre-treated in the same way as silicate ceramics like lithium disilicate, the obtained bond strength is lower. Using the correct pre-treatment protocol, however, it is possible to establish a strong and durable chemical bond between the tooth structure and the zirconia. Otherwise, it would not be possible to place single-retainer resin-bonded bridges made of high-strength zirconia (3Y-TZP) successfully, for example. Their design is largely non-retentive, so that a strong bond is of paramount importance. It is established by air-abrading the bonding surface of the zirconia retainer wing with aluminium oxide (50 μm) at a low pressure (approx. 1 to 2.5 bar) after try-in^11,12, followed by ultrasonic cleaning, the use of a restoration primer that contains 10-MDP¹³ and the application of a high-performance resin cement like PANAVIA™ V5 (Kuraray Noritake Dental Inc.)¹⁴. Using this protocol with a predecessor of the resin cement just mentioned, ten-year survival and success rates were above 90 percent¹⁵. The described protocol is in line with the APC concept recommended by Prof Dr. Markus Blatz, which includes (A) airborne-particle abrasion, (P) zirconia primer, and (C) adhesive composite resin application¹⁶.

CONCLUSION

Using an appropriate protocol including small particle air-abrasion after try-in and a high-performance adhesive resin cement system with MDP primers, a strong and long-lasting chemical bond to zirconia can be established.

7. ZIRCONIA IS UNSUITABLE FOR RUSH CASES DUE TO THE NEED OF SINTERING THE RESTORATIONS AFTER MILLING

By using zirconia variants that are suitable for speed sintering, smaller restorations can be produced within very short time. Single-unit restorations and small bridges (up to three units) made of materials of the KATANA™ Zirconia Multi-Layered Series, for example, may be speed-sintered within 54 minutes, provided that a suitable furnace is used. This leads to a considerable reduction of the production time and is a great option for rush cases. For a true chairside workflow and same-day dentistry, KATANA™ Zirconia Block is a great option. It offers the same optical and mechanical properties as KATANA™ Zirconia STML and can be sintered even faster – in just 18 minutes.

CONCLUSION

By using suitable zirconia materials and equipment, production times of zirconia restorations are no longer an issue when it comes to rush cases.

8. ALL HIGH-STRENGTH CERAMICS HAVE A SIMILARLY WIDE RANGE OF INDICATIONS

In fact, the range of indications varies with the flexural strength and fracture toughness of the materials. While the use of lithium disilicate is limited to the production of single-tooth restorations and small bridges, zirconia typically covers a wider range of indications, with the high-strength variants being even suited for long-span bridges. The most versatile variants of zirconia are those with flexural strength gradient – like KATANA™ Zirconia YML. This material offers a particularly high translucency in the enamel layer and a high strength in the body layers. Therefore, it is well suited for the production of single-tooth restorations and of highly complex structures such as long-span bridges – depending on where the restoration is positioned in the disc.

CONCLUSION

Zirconia offers a wider range of indications than lithium disilicate. By selecting one of those variants with a multi-layered structure offering flexural strength gradation, it is possible to cover virtually every indication, while other variants are better suited for specific needs (highest translucency option for aesthetically demanding cases, highest strength option for complex long-span designs).

ZIRCONIA A TRUE ALLROUNDER

Modern versions of dental zirconia are high-performance materials with well-balanced optical and mechanical properties typically suitable for a wide range of indications. As a zirconia user, you may choose to employ a single material with flexural strength gradation for virtually every situation or prefer to select different products depending on case-specific demands. You have the freedom to select the preferred finishing technique from traditional layering to just polishing and may opt for minimally invasive restoration designs. The latter is due to proven protocols establishing a long-lasting bond to zirconia. For everyone with particularly high quality demands, the KATANA™ Zirconia Multi-Layered series is worth a try. The raw material composition is unique, the powder is developed in-house in Japan and the blanks are produced in a perfectly aligned procedure delivering a homogeneous, densely pressed material for restorations with an accurate fit, high strength and superior edge stability.

REFERENCES

<sup>1. F. Beuer, J. Schweiger, ConsEuro 2015 London, Kuraray Satellite Symposium, May 14th 2015. 
2. Kwon SJ, Lawson NC, McLaren EE, Nejat AH, Burgess JO. Comparison of the mechanical properties of translucent zirconia and lithium disilicate. J Prosthet Dent. 2018 Jul;120(1):132-137. 
3. Reale Reyes A, Dennison JB, Powers JM, Sierraalta M, Yaman P. Translucency and flexural strength of translucent zirconia ceramics. J Prosthet Dent. 2023 Apr;129(4):644-649. 
4. Harada K, Raigrodski AJ, Chung KH, Flinn BD, Dogan S, Mancl LA. A comparative evaluation of the translucency of zirconias and lithium disilicate for monolithic restorations. J Prosthet Dent. 2016 Aug;116(2):257-63. 
5. Janyavula S, Lawson N, Cakir D, Beck P, Ramp LC, Burgess JO. The wear of polished and glazed zirconia against enamel. J Prosthet Dent. 2013 Jan;109(1):22-9. 
6. Preis V, Weiser F, Handel G, Rosentritt M. Wear performance of monolithic dental ceramics with different surface treatments. Quintessence Int. 2013 May;44(5):393-405. 
7. Lawson NC, Janyavula S, Syklawer S, McLaren EA, Burgess JO. Wear of enamel opposing zirconia and lithium disilicate after adjustment, polishing and glazing. J Dent. 2014 Dec;42(12):1586-91. doi: 10.1016/j.jdent.2014.09.008. Epub 2014 Sep 23. PMID: 25257823. 
8. Sripetchdanond J, Leevailoj C. Wear of human enamel opposing monolithic zirconia, glass ceramic, and composite resin: an in vitro study. J Prosthet Dent. 2014 Nov;112(5):1141-50. 
9. Hartkamp O, Lohbauer U, Reich S. Antagonist wear by polished zirconia crowns. Int J Comput Dent. 2017;20(3):263-274. 
10. Shah N, Nerkar H, Badwaik P, Ahuja B, Malu R, Bhanushali N. An evaluation of antagonist enamel wear opposing full-coverage zirconia crowns versus other ceramics full-coverage crowns and natural enamel - An umbrella review. J Indian Prosthodont Soc. 2024 Jul 1;24(3):217-224. 
11. Kern M. Bonding to oxide ceramics—laboratory testing versus clinical outcome. Dent Mater. 2015 Jan;31(1):8-14. 
12. Kern M, Beuer F, Frankenberger R, Kohal RJ, Kunzelmann KH, Mehl A, Pospiech P, Reis B. All-ceramics at a glance. An introduction to the indications, material selection, preparation and insertion techniques for all-ceramic restorations. Arbeitsgemeinschaft für Keramik in der Zahnheilkunde. 3rd English edition, January 2017. 
13. Al-Bermani ASA, Quigley NP, Ha WN. Do zirconia single-retainer resin-bonded fixed dental prostheses present a viable treatment option for the replacement of missing anterior teeth? A systematic review and meta-analysis. J Prosthet Dent. 2021 Dec 7:S0022-3913(21)00588-6. 
14. Bilir H, Yuzbasioglu E, Sayar G, Kilinc DD, Bag HGG, Özcan M. CAD/CAM single-retainer monolithic zirconia ceramic resin-bonded fixed partial dentures bonded with two different resin cements: Up to 40 months clinical results of a randomized-controlled pilot study. J Esthet Restor Dent. 2022 Oct;34(7):1122-1131. 
15. Kern M, Passia N, Sasse M, Yazigi C. Ten-year outcome of zirconia ceramic cantilever resin-bonded fixed dental prostheses and the influence of the reasons for missing incisors. J Dent. 2017 Oct;65:51-55. doi: 10.1016/j.jdent.2017.07.003.
16. 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.</sup>

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Achieving consistent, high-quality ceramic restorations requires more than just premium materials — it demands a deep understanding of your tools and processes. The CERABIEN™ MiLai Firing Guide is designed to help dental technicians unlock the full potential of this advanced micro-layering porcelain system. With tips on optimal furnace positioning, trial baking, and troubleshooting, this guide supports efficient, aesthetic results every time. Whether you're new to CERABIEN™ MiLai or looking to refine your firing process, this resource lays the groundwork for success.

Case by Andreas Chatzimpatzakis

When dental technicians from all over the world started using the micro-layering technique, they simply combined a reduced number of porcelains and stains from their original porcelain system. After some time, porcelains specifically designed for micro-layering were introduced to the dental market. Consequently, early adopters had to decide whether or not to switch to one of those new systems.

For me as a frequent user of CERABIEN™ ZR (Kuraray Noritake Dental Inc.), a porcelain system based on synthetic feldspathic porcelain developed for porcelain layering on zirconia frameworks, switching to any micro layering porcelain system was not an option. However, when I had the chance to test the brand-new CERABIEN™ MiLai porcelains and internal stains (Kuraray Noritake Dental Inc.), I grabbed it for two reasons. Firstly, the simplicity! I was surprised how easily I could achieve a high aesthetic result without using too many different ceramic powders. Secondly with this system, I have a micro-layering porcelain system at my disposal that works for both, zirconia and lithium disilicate. Farther more, the product is well-aligned to CERABIEN™ ZR – and offers a very similar handling.

CASE EXAMPLE

The following case is a nice example of how it may be used in the anterior region. The male patient had already been treated with monolithic zirconia crowns from another dental laboratory in the posterior region. Now, he desired a maxillary anterior smile makeover due to discoloured composite restorations and signs of tooth wear. The decision was made to produce six veneers with frameworks made of lithium disilicate (Amber Press), individualized with CERABIEN™ MiLai using the micro-layering technique. I would like to thank the prosthodontist Dr Konstantina Aggelara for the excellent collaboration and the intra oral photos.

For layering, I simply applied CERABIEN™ MiLai Value Liner 1. Then, I used CCV2 in the cervical and Tx in the incisal area, as well as Liner 2 for the mamelons. Internal stains were applied after the first bake. Subsequently, the canines were completed with LT1. The lateral and central incisors were built up with LT1 in the cervical area, Creamy Enamel on the marginal ridges and the middle and E2 mixed with Tx in the ratio 70/30 in the incisal area.

Fig. 1. Initial situation: The patient was unhappy with his lip line and facial appearance, …

Fig. 2. … particularly due to discoloured composite restorations and severe wear in the maxillary anterior region.

Fig. 3. Shade determination after tooth preparation.

Fig. 4. Restorations produced with Amper Press (Shade LT A2), individualized with CERABIEN™ MiLai.

Fig. 5. Lateral view: The internal play of colours (internal stains) creates a nice effect. Natural shading and surface texture.

FINAL SITUATION

Fig. 6a and 6b. Restorations placed in the patient’s mouth.

THE PERFECT COMPLEMENT TO MY STANDARD PORCELAIN SYSTEM

As hoped, CERABIEN™ MiLai offers similarly great handling properties as CERABIEN™ ZR – probably mainly due to the fact that it is also based on synthetic feldspathic ceramic. It is not only responsible for consistent handling, but also for predictable optical properties, eliminating unwanted shadow effects. As the system is designed for micro-layering, it offers a natural appearance when applied in thin layers. This fact – in addition to the broader compatibility (to high-strength oxide and silicate ceramics) – makes it worthwhile to consider using a specific porcelain system for micro-layering. Experience shows that it works just as well on zirconia as it does on lithium disilicate, so that combining both framework materials in a single patient becomes a lot easier, while the line-up is neat.

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..

Recently we introduced CERABIEN™ MiLai - a brand-new line of porcelains and internal stains specially developed for micro-layering on zirconia and lithium disilicate.

In this special edition of BOND magazine, we're excited to share the very first clinical cases using this innovative system. From beautifully natural veneers to streamlined lab workflows, these real-world examples show just what’s possible with CERABIEN™ MiLai.

If you’re curious about what the future of aesthetic dentistry looks like, this is the place to start!

Start Reading: BOND | VOLUME 12 | 07/2025

Previous versions:

BOND | VOLUME 11 | 07/2024

BOND | VOLUME 10 | 10/2023

BOND | VOLUME 9 | 08/2022

BOND | VOLUME 8 | 12/2021

BOND | VOLUME 7 | 10/2020

Case by Francesco Ferretti, MDT

Is it possible to produce lifelike porcelain veneers using lithium disilicate and a porcelain system with a reduced number of internal stains and porcelains designed for micro-layering? This is what we wanted to find out when we decided to test the new CERABIEN™ MiLai line-up. As loyal users of the CERABIEN ZR family for porcelain layering on zirconia, we hoped that the new product would offer similar handling and optical properties.

The CERABIEN™ MiLai line-up consists of 15 internal stains and 16 porcelains, which are - like CERABIEN ZR - based on synthetic feldspathic porcelain technology from Kuraray Noritake Dental Inc. With a comparatively low firing temperature of 740 °C (or 1,364 °F), the system may be used on zirconia as well as silicate ceramic restorations, provided that the CTE value of the materials is between 10.2 and 10.5 × 10^-6/K (50 °C – 500 °C). This is true for lithium disilicate, our preferred base material for the production of ceramic veneers. The thickness of the porcelain layer is usually smaller than 0.5 mm, which allows us to exploit the aesthetic potential of the underlaying ceramic, while creating some individual effects for the underlying structure and the enamel. A clinical case predestined for the use of the new system is shown below.

Fig. 1. Young male patient with discoloured composite restorations on his maxillary central incisors.

Fig. 2. The patient was unhappy with his smile aesthetics, so that it was decided to place more durable ceramic veneers.

Fig. 3. Appearance of the central incisors after minimally invasive tooth preparation.

Fig. 4. Veneers made of lithium disilicate individualized with CERABIEN™ MiLai placed on the model.

Fig. 5. Intraoral view of the teeth after adhesive cementation of the veneers.

Fig. 6. Close-up view of the anterior teeth.

Fig. 7. Smooth optical integration of the veneers: They show some individual effects and are virtually indistinguishable from natural tooth structure of the adjacent lateral incisors.

Fig. 8. Black-and-white photograph of the maxillary anterior teeth.

Fig. 9. Smile aesthetics.

Fig. 10. Beautiful treatment outcome.

COMPACT SYSTEM

The compact line-up of CERABIEN™ MiLai with its nicely developed internal stains and porcelains enables us to imitate the patient’s natural teeth very well in the great majority of cases. Shades are easily selected and the favourable consistency of the porcelains facilitates application in thin layers. Due to the reduced thickness of the porcelain layer, it is possible to play with the optical properties of the underlying lithium disilicate, creating a final restoration with a natural appearance despite the simplified procedure.

Dentist:

FRANCESCO FERRETTI, MDT

Born in Rome on March 15, 1957, Francesco Ferretti received his dental technician diploma from the Edmondo de Amicis Institute in Rome and began working independently in 1980. His dental career has been versatile and impressive - working under Prof. Mario Martignoni, being partner at ORAL DESIGN Center in Rome (founded by Mr. Willi Geller and Mr. Francesco Felli) and having his own Estech Dental Studios, are just some of the highlights.

He taught the advanced course in prosthesis at the University of Chieti from 2002 to 2010 and the postgraduate course in prosthesis at the University of Naples Federico II in 2007.

He has been using metal free methods for more than 30 years, specialized in prosthesis and implants, has published articles and research in Italian, American, Russian and Asian magazines and has been a speaker at various international conferences and courses.