Case report by Dr. Wissam Dirawi, DDS

During the last decade, zirconia has increasingly established itself as the material of choice in oral prosthodontic rehabilitation. Its great mechanical and inert properties are the main reason for this trend. Since the introduction of multi-layered zirconia blanks more than ten years ago, the optical properties have been improved dramatically. The multi-layered zirconia used nowadays (e.g. KATANA™ Zirconia YML from Kuraray Noritake Dental Inc.) offers well-balanced mechanical properties, translucency and colour. It allows dental technicians from all over the world to produce aesthetic full-contour restorations that are merely stained.

Even in the anterior region, stained monolithic restorations may be an option. Factors such as the age of the patient, the internal colour structure of the adjacent dentition, the number of teeth to be restored (one versus all four or six maxillary anterior teeth), the aesthetic demands of the patient and financial aspects should be taken into account in the material selection process. In the case described below, full-contour zirconia was selected for several reasons.

BACKGROUND

The 71-year-old female presented in the clinical due to aesthetic problems in the maxillary anterior region. Oral hygiene was good and the patient was a non-smoker. Infraposition of the existing implant-based crown (Nobel Biocare Brånemark RP fixture) in the position of the right central incisor (tooth #11 according to the FDI notation) was evident. Moreover, gingival retraction was observed on the maxillary right lateral incisor (tooth #12), while the left lateral incisor (tooth #22) has a major composite filling with discolouration. The patient expressed the desire to adjust the gingival level differences and to restore the four maxillary incisors with all-ceramic crowns for optimal aesthetics.

Fig. 1. Initial situation: Frontal view.

Fig. 2. Initial situation: Facial view.

Fig. 3. Initial situation: Occlusal view of the maxilla.

Fig. 4. Initial situation: Occlusal view of the mandible.

MATERIAL SELECTION

Due to the decision to restore all four anterior incisors, monolithic zirconia was a suitable material option. It would allow the team to obtain the desired results within the financial framework. In order to meet the aesthetic demands of the patient, provide for the required mechanical properties and allow for proper masking of the underlying structures, KATANA™ Zirconia YML was selected. It offers colour, translucency and flexural strength gradation throughout the multi-layered blank.

TREATMENT PROCEDURE: FROM PREP TO TEMPORIZATION

In order to design the indirect restorations, a digital impression was taken with an intraoral scanner and the data was transferred to the dental laboratory Teknodont in Malmoe, Sweden. There, a digital wax-up was created. After patient approval, a matrix was produced and sent to the clinic. Here, the old restorations were removed and the three maxillary incisors (all but the one replaced by an implant) prepared for full coverage restorations. A healing abutment was placed on the implant and a temporary bridge produced chairside using the matrix and Protemp 4 Temporization Material (3M) in the shade A3. Subsequently, a gingivectomy was carried out with a ceramic burr (Ceratip, Kt.314.016 – KOMET) in the buccal aspect of the left central and lateral incisor.

Fig. 5. Chairside-produced temporary in the patient’s mouth.

After the patient’s approval of the aesthetics, phonetics and function of the temporary restoration, the situation was captured with an intraoral scanner again. This allowed the team to duplicate the shape of the construction. Based on the acquired data, a new set of splinted temporary crowns made of PMMA (HUGE Multilayer PMMA) in the shade A3 was milled in laboratory. They were placed to allow the patient to further evaluate the aesthetic appearance and function for a couple of weeks. The patient was happy with the phonetics, function and appearance of the crowns, which were merely slightly too bright in comparison to the adjacent teeth, and approved the shape for the production of the permanent restorations.

Fig. 6. Printed model …

Fig. 7. … with splinted PMMA crowns.

Fig. 8. Lab-made temporary restorations.

Fig. 9. Long-term temporary in place: Lateral view from the right.

Fig. 10. Long-term temporary in place: Frontal view.

Fig. 11. Long-term temporary in place: Lateral view from the left.

FINAL RESTORATIONS: PRODUCTION AND CEMENTATION

Based on the dataset of the temporary restorations, four separate crowns – one implant and three tooth-based – were designed in full contour. Without any anatomical reduction, the restorations were milled from KATANA™ Zirconia YML. Based on the evaluation of the temporary restoration, the shade selected this time was A3.5. CERABIEN™ ZR FC Paste Stain was used for external staining and glazing of the surface. Still in the laboratory, the implant-based crown was cemented to the gold-shaded titanium abutment (Elos Medtech) with PANAVIA™ V5 (Kuraray Noritake Dental Inc.) in the shade opaque for an improved masking effect.

While the abutment crown was screwed onto the implant and the screw hole closed with composite, the three tooth-based crowns were placed using PANAVIA™ SA Cement Universal (Kuraray Noritake Dental Inc.).

Fig. 12. Final restorations on the model.

Fig. 13. Intraoral situation prior to restoration placement.

CONCLUSION

Multilayered zirconia is a suitable material for many clinical situations. Due to the availability of modern types of highly translucent, multi-layered blanks, it is possible to produce aesthetic outcomes even when using the material monolithically – not only in the posterior region, but also in the aesthetic zone in some indications. The present case shows that very good results and patient satisfaction can be obtained. And due to outstanding mechanical properties, these outcomes may be expected to last for a long time.

Fig. 14. Immediate treatment outcome: Facial view.

Fig. 15. Immediate treatment outcome: Frontal view.

Fig. 16. Immediate treatment outcome: Occlusal view.

Dentist:

WISSAM DIRAWI

Dr. Wissam Dirawi, Malmoe, Sweden. DDS.
Specialist in Oral Prosthodontics and Senior Adviser at Aqua Dental.

2000 Master´s degree in dentistry.
2000 - 2018 General Dentist in public dental care and private practice.
2011 - 2018 Part-time teacher and researcher at Malmö University, Faculty of Dentistry.
2018 Specialist in Oral Prosthodontics. Senior clinical adviser. Lecturer.

References

- Alfadhli R, Alshammari Y, Baig MR, Omar R. Clinical outcomes of single crown and 3-unit bi-layered zirconia-based fixed dental prostheses: An up to 6- year retrospective clinical study: Clinical outcomes of zirconia FDPs. J Dent. 2022 Dec;127:104321.
- Le M, Papia E, Larsson C. The clinical success of tooth- and implant-supported zirconia-based fixed dental prostheses. A systematic review. J Oral Rehabil. 2015 Jun;42(6):467-80.
- Alammar A, Blatz MB. The resin bond to high-translucent zirconia-A systematic review. J Esthet Restor Dent. 2022 Jan;34(1):117-135.
- Sadowsky SJ. Has zirconia made a material difference in implant prosthodontics? A review. Dent Mat 2020; 36: 1–8.
- Mazza LC, Lemos CAA, Pesqueira AA, Pellizzer EP. Survival and complications of monolithic ceramic for tooth-supported fixed dental prostheses: A systematic review and meta-analysis. J Prosthet Dent 2022; 128: 566–74.
- Passia N, Mitsias M, Lehmann F, Kern M. Bond strength of a new generation of universal bonding systems to zirconia ceramic. J Mech Behav Biomed Mater. 2016; 62:268–274.
- Sailer I, Makarov NA, Thoma DS, Zwahlen M, Pjetursson BE. All-ceramic or metal-ceramic tooth- supported fixed dental prostheses (FDPs)? A systematic review of the survival and complication rates. Part I: Single crowns (SCs). Dent Mater 2015; 31:603-623.
- Pjetursson BE, Sailer I, Makarov NA, Zwahlen M, Thoma DS. All-ceramic or metal-ceramic tooth- supported fixed dental prostheses (FDPs)? A systematic review of the survival and complication rates. Part II: Multiple-unit FDPs. Dent Mater 2015; 31:624–639.

By Manabu Suzuki, Director of Dental Division, Kuraray America, Inc.

Kiyoko Ban, a prominent figure in the dental technology field, has made a lasting impact as a researcher, developer, and founder of Noritake Dental business (Fig. 1). Renowned for her contributions to dental porcelains like Noritake's CZR and EX-3, and KATANA™ Zirconia, Ms. Ban stands as a pivotal force in the global advancement of dental technology, earning her the esteemed reputation of developer and marketer within the dental technology community.

After completing her university education in Nagoya, Ms. Ban initially assisted in her family's gas station business. However, driven by a desire for a career change, she enrolled in a newly established dental technician college in Nagoya at the age of 30. Her aspiration was to enter a field where gender distinctions held no sway, offering the potential for worldwide recognition based on technical mastery.

In 1977, a college-sponsored tour to American dental laboratories ignited Ms. Ban's dream to work in the United States. However, she delved into research across various fields such as chromatology (the science of color), ceramics and metals, finding a newfound passion for research over clinical work after graduation because she was offered a "Curriculum Chief" position from the college when she graduated (Fig. 2).

Fig. 2. Ms. Ban, a curriculum chief at the Dental Technicians College, devoted her evenings to material research.

Fig. 3. In the 1990s, Ms. Ban actively engaged in promoting EX-3 through sales efforts in Italy.

Her teaching career spanned from the age of 34 to around 40, during which she pioneered porcelain training sessions for technical improvement and arranged lectures over weekends by famous speakers such as Masahiro Kuwata.

At the age of 40, she resigned teaching career and pursued her research career. The opportunity to conduct full-scale experiments led her to the discovery of a company with advanced ceramic technology "Noritake Co., Limited", renowned for its tableware. In 1986, Cusp Dental Supply, a research institute, was established by Ms. Ban in Nagoya, focusing on the development of materials for PFM crowns. The commercialization of Super Porcelain AAA (EX-3) in 1987 marked a significant milestone, addressing issues prevalent in porcelain materials of that time, such as cracks, greening, and fluorescence.

She began traveling all over Japan and around the world to sell the products she had developed and went on to develop new products that were needed by dental technicians worldwide (Fig. 3). She continued to develop new products such as CZR, CZR Press, and KATANA™, the world's first multilayer zirconia.

Ms. Ban has been actively involved in mentoring students and graduates seeking opportunities to work overseas. During summer vacations, she took students and professionals interested in working abroad to countries like Australia, Germany, and the United States. The aim was to visit dental clinics, dental technician schools, and laboratories, fostering exposure and learning in an international context.

Simultaneously, Ms. Ban delved into researching non-precious dental technology. Inspired by her exposure to the term "non-precious" during her time in the United States, she anticipated its potential in Japan. Her research presented at lectures and events highlighted the shift in the landscape as the price of gold surged, rendering precious alloys containing significant amounts of gold impractical for PFM crowns.

As the demand for their developed products grew, the need for global acceptance became apparent. In 1990, Cusp Dental Research was established in Manhattan, New York, marking Ms. Ban's foray into establishing a company overseas. Despite the unfamiliarity with legal procedures and the challenges of setting up a foreign company, Ms. Ban, driven by determination, overcame these hurdles. The establishment of the company in the United States expanded their presence internationally Fig. 4).

Fig. 4. Capturing the essence of ISC 1996 - the International Symposium on Ceramics in Orlando, FL..

Noritake Dental Supply Co., Limited was established in 1998 by the Noritake Co., Limited, which aimed to further expand its dental business. Despite the absence of a capital relationship with Noritake at the time of establishing the research laboratory, Ms. Ban played a key role in joint research efforts with Noritake. Then she was invited to this company as the position of president, owning 60% of the stock, while Noritake held 40% (Fig. 5).

Besides Noritake Dental business, she continued expansion with the establishment of a dental laboratory in Boston in 1995. Despite the challenges posed by the September 11, 2001 World Trade Center incident, they acquired their building in Boston, integrating their New York laboratory into the Boston operations.

Ms. Ban's tenure as president of Noritake Dental Supply persisted until 2009, but organizational changes following the merger with Kuraray in 2011 led to her transition into an advisory role (Fig. 6). Despite the shift in responsibilities, her commitment to the dental technician profession remained steadfast.

Fig. 5. Noritake Dental Supply Inc Inauguration Party, 1998.

Kiyoko Ban's path encapsulates not just a career but a legacy in the field of dental technology. From her early struggles in a tooth carving class to establishing and expanding international laboratories, Ms. Ban's story is one of determination, innovation, and a deep-rooted commitment to advancing the dental technician profession.

Fig. 6. A scene from Ms. Ban’s retirement celebration as Noritake Dental Supply president, surrounded by esteemed dental technicians from around the world.

UNFORGETTABLE WEEK

In April, a team from Kuraray Noritake Dental’s European arm accompanied 18 Key Opinion Leaders (KOLs) from Germany, Italy, Spain, France, Turkey, Poland, England, Romania, Switzerland, the Czech Republic, and Denmark to Kuraray Noritake Dental’s roots in Japan. The week was an incredible blend of professional exchange, cultural immersion, and shared experiences.

The European group included an interdisciplinary team of dentists, dental technicians, professors, and researchers. They toured Kuraray Noritake Dental’s two production sites in Niigata (chair-side manufacturing) and Nagoya (lab-side products) and visited the Head Office in Tokyo.

Visit to the production facility for chair-side products in Niigata.

INTERDISCIPLINARY AND INTERNATIONAL EXCHANGE

As you can imagine, this was a fantastic opportunity for both Kuraray Noritake Dental’s European employees and KOLs to have lively exchanges with Japanese developers and production personnel. Our KOLs highly appreciated the opportunity to present their own work and ongoing results while sharing tips and techniques with the Japanese members.

The importance of this trip for both the KND employees and the European travel group was underlined by the participation of the Head of Kuraray Noritake Dental (Yamaguchi-san) and the inventor of Noritake dental porcelain (Kiyoko Ban). In her welcome speech, she emphasized what an extraordinary opportunity this interdisciplinary and international exchange represents and how pleased she was about the numerous visitors.

Kiyoko Ban during her welcome speech for the delegation from Europe.

Head of Kuraray Noritake Dental (Yamaguchi-san) together with Dr. David Gerdolle, Jakab Daniel, and Honoré Morel during lunch in the Tokyo office.

The tour proved that there really is no substitute for face-to-face, hands-on interaction when it comes to discussions between product developers and specialists as well as seeing behind the scenes for a direct insight into production and quality assurance.

As Dr David Gerdolle said: “Kindness, perfect organization, dedication to precision and professionalism are a rare and precious combination in the actual world. My deepest gratitude to the Kuraray Noritake company for this unforgettable week in Japan.”

EXPLORING JAPAN

However, the visit wasn’t all about work. There was a fabulous opportunity to see Mount Fuji in all its glory on the train ride from Nagoya to Tokyo and as well as a unique chance to explore Japanese culture. Not to forget the visit to Noritake Garden in Nagoya, where the history and traditional art of fine tableware through to modern high-tech materials are on display.

Exhibitions at the Noritake Museum in Nagoya.

As Daniel Dunka (MDT) said: “The whole trip was absolutely wonderful, and I’m grateful to Noritake for the invitation. It has been a wonderful experience mingling with colleagues from all over the world in such a beautiful environment. It has been an inspiration for me and I look forward to continuing to work with your wonderful materials and of course your amazing team.

Jakab Daniel (MDT) added: “The organizational culture [in Japan] is fascinating, it is amazing to be a part of the whole manufacturing process of Noritake ceramics, Zirconium KATANA and all Kuraray products. Very good discussions, opinions, suggestions” while MDT Mathias Berger from France summed up the whole visit with: “Thank you so much for your invitation, I realized a dream.” 

Available Now!

Have you ever produced a zirconia restoration without obtaining the outcome you expected? Most dental technicians probably have. The bad thing is that aesthetic flaws such as colour deviations or white spots and technical issues like cracks can occur and require remakes. The good thing is, however, that those problems are usually avoidable. Do you know how?

We would like to show you – in the new KATANA™ Zirconia Troubleshooting Handbook we just completed. On 30 pages, this handbook summarized the most important facts about modern zirconia-based restorative materials, their selection, the KATANA™ Zirconia line-up and, finally, possible aesthetic or technical problems, their origin and solutions to overcome them.

Let us assume that the beauty of your restorations is limited due to a lack of translucency. By looking up the problem “lack of translucency”, you will find a compact, well-structured overview of possible causes and adequate solutions. The recommendations include selecting dry instead of wet milling, abstaining from sandblasting the restoration surface and checking of the sintering parameters, quality of the sintering beads and position of the restoration in the furnace. For more details, problems and solutions, download the handbook!

DOWNLOAD NOW

Article by Prof. Lorenzo Breschi

Fewer bottles, more choices – this is possibly the shortest way to describe the category of universal resin cements. Being self-adhesive, these dual-cure resin-based cements allow for a single-component workflow without the need for separate tooth or restoration primers in many clinical situations. The bond strength obtained in this way is usually high enough to provide for a stable bond between the tooth and the restoration in a wide range of indications. However, it is slightly lower than that achieved with conventional resin cement systems consisting of several components (typically tooth primer, resin cement and restoration primer).

Apart from the self-adhesive application mode, universal resin cements may be combined with additional system components to increase the bond strength to tooth structure or the restorative material, respectively. This opens up new possibilities with regard to the product’s use: depending on the required or desired bonding performance, the universal resin cement may be applied alone or in combination with a tooth primer, a restoration primer or both components. In addition, hybrid concepts become feasible, as explained in this article that focuses on PANAVIA™ SA Cement Universal (Kuraray Noritake Dental Inc.) as an example.

Self-adhesive luting: for many indications

PANAVIA™ SA Cement Universal is a dual-cure universal resin cement that is indicated for a wide range of applications when used in the self-adhesive mode. The bond established to restorative substrates (including silicate ceramics) is high without the use of a separate primer or silane^1-4. This is due to two different adhesive monomers contained in the formulation – the Original MDP Monomer and the LCSi Monomer (a long carbon-chain silane coupling agent responsible for a strong chemical bond to silicate ceramics). Hence, it is possible to use the resin cement without any additional component applied on the side of the restoration – even in cases with a lack of retention and consequently high bond-strength requirements.

A strong bond to enamel and dentin is also obtained in the self-adhesive mode. In certain situations, however, it may be useful to further increase the bond strength to tooth structure with the aid of a tooth primer.

Adhesive luting: for challenging situations

The tooth primer recommended for PANAVIA™ SA Cement Universal is CLEARFIL™ Universal Bond Quick (Kuraray Noritake Dental Inc.). Its application is recommended whenever a user feels that the treatment would benefit from an extraordinarily strong and durable chemical bond, i.e. in particularly challenging situations with insufficient mechanical retention. The effectiveness of this measure has been confirmed in an in-vitro study conducted in Japan, in which the 24-hour micro-tensile bond strength to dentin was increased significantly by the application of the universal adhesive⁵. When a separate adhesive is used, however, the importance of a completely dry working field increases. The reason is that the moisture tolerance of resin cements is usually higher than that of adhesives. Consequently, the application of a rubber dam is highly recommended.

Selective adhesive luting: for short abutments and subgingival margins

For situations in which proper isolation of the working field with a rubber dam is difficult, a third application option is available and proposed by a group of Italian researchers: Selective Adhesive Luting. In this case, CLEARFIL™ Universal Bond Quick is applied solely to those parts of the prepared tooth that allow for proper moisture control, while relying on the self-adhesive functionality of PANAVIA™ SA Cement Universal in areas where it is challenging to obtain the desired dry working field. Situations which are predestined for this technique are abutment teeth with a subgingival preparation margin and particularly short abutment teeth (that hinder the placement of a rubber dam).

The effectiveness of the selective adhesive luting technique has been verified in an in-vitro study that compared the three adhesive strategies – self-adhesive luting, full adhesive luting and selective adhesive luting – with the aid of shear bond strength testing⁶. The results of the tests show that users are able to enhance the bond strength of PANAVIA™ SA Cement Universal to dentin and enamel by applying the adhesive to a part of the tooth surface only. For the cementation system consisting of PANAVIA™ SA Cement Universal and CLEARFIL™ Universal Bond Quick, the full adhesive and the selective adhesive approach led to similar outcomes.

For situations in which proper isolation of the working field with a rubber dam is difficult, a third application option is available and proposed by a group of Italian researchers: Selective Adhesive Luting.

RECOMMENDED STEPS FOR SELECTIVE ADHESIVE LUTING

Fig. 1. Tooth preparation.

Fig. 2. Selective etching of the enamel with phosphoric acid etchant.

Fig. 3. Application of the universal adhesive + air-drying.

Fig. 4. Crown placement after application of the resin cement into the crown.

Fig. 5. Tack-curing.

Fig. 6. Excess removal and final light curing.

Fig. 7. Treatment outcome at a recall after one year.

Benefits of selective adhesive luting

Apart from the desired (long-term) increase in bond strength achieved by applying a separate adhesive to a part of the or the whole prepared tooth surface, the technique offers additional benefits. Compared to multi-step cementation systems, the protocol is simplified as no separate restoration primer is needed. Light-curing of the adhesive is not required as long as the user stays within the recommended system. And in contrast to the full adhesive approach requiring rubber dam placement, the need for this step is eliminated in the selective adhesive approach. In this way, the chair-time is reduced and patient comfort increased.

Conclusion

Depending on the indication, clinical variables and individual preferences, users of universal resin cements like PANAVIA™ SA Cement Universal may select the technique that is likely to deliver the best clinical outcomes. It is this flexibility and the generally wide range of applications that makes the innovative product category truly universal. With fewer components to be used, universal materials facilitate the streamlining and standardization of clinical procedures, while with fewer bottles to be stored, they help staff gain control over order and storage management as well.

Dentist:

LORENZO BRESCHI

Prof. Lorenzo Breschi is Professor of Restorative Dentistry and Dental Materials at the University of Bologna. He is actively involved in research on the ultrastructural aspects of enamel and dentin. He is Past-President of the Academy of Dental Materials (ADM), President-Elect of the European Federation of Conservative Dentistry (EFCD), President-Elect of the Dental Materials Group IADR, President-Elect of the Italian Academy of Conservative Dentistry (AIC), President-Elect of the International Academy of Adhesive Dentistry (IAAD).

References

1. Cowen M, Cunha S, Powers JM. Novel Cement Bond Strength to Multiple Substrates. DENTAL ADVISOR Biomaterials Research Center, Biomaterials Research Report, Number 132 – June 16, 2020.
2. Patel N, Anadioti E, Conejo J, Ozer F, Mante F, Blatz M. Bond Strength of Different Self-Adhesive Resin Cements to Zirconia” (2021). Dental Theses. 62. https://repository.upenn.edu/dental_theses/62.
3. Yoshihara K, Nagaoka N, Maruo Y, Nishigawa G, Yoshida Y, Van Meerbeek B. Silane-coupling effect of a silane-containing self-adhesive composite cement. Dent Mater. 2020 Jul;36(7):914-926.
4. Irie M, Tokunaga E, Maruo Y, Nishigawa G, Yoshihara K, Nagaoka N, Minagi S, Matsumoto T. Shear bond strength of a resin cement to CAD/CAM Blocks for molars. P-2, 37th Annual Meeting of the Japanese Society of Adhesive Dentistry 2018.
5. Ohara N. Bonding strength of resin cement containing silane coupling agent to dentin or core resin. Results presented at the 150th meeting of the Japanese Society of Conservative Dentistry.
6. Breschi L, Josic U, Maravic T, et al. Selective adhesive luting: A novel technique for improving adhesion achieved by universal resin cements. J Esthet Restor Dent. 2023;1-9. doi:10.1111/jerd.13037.

May 15th, 2024 at 21:00 CET

From margin elevation to restoration

Did you ever wonder how to optimize teamwork, efficiency, and patient satisfaction in the context of a combined endodontic and restorative treatment? As a general or restorative dentist, you can easily contribute to streamlined procedures and better outcomes for your patients. The measures to be taken are in the center of this webinar by experienced and knowledgeable Dr. Wiktor Pietraszewski.

Endodontic treamtment and pre-refferal strategies

In the first part of his lecture, Dr. Pietraszewski reveals how to proceed before referring the patient to the endodontic specialist to improve the overall prognosis of the treatment on the one hand, and the patient experience on the other. Materials and techniques, such as deep margin elevation, caries removal, and tooth build-up, will be described and examined. But most importantly, many practical tips will be shared with the audience.

Post-endodontic restoration options for long term success

In the second part, the speaker will focus on post-endodontic treatment. He will describe the available materials and types of post-endodontic restorations. Dr. Pietraszewski will shed light on the most important factors guiding the most crucial treatment decisions and will elaborate on the factors influencing long-term success.

Go to the Facebook Event of the webinar and click „Livevideo”!

We look forward to seeing you!

About the speaker

Dr. Pietraszewski is a general and restorative dentist working in private practice in London. He utilizes biomimetic adhesive protocols in his restorative cases and uses gold standard materials to emulate the natural appearance, bio-mechanical function, and internal structure of teeth when restoring them.

He has a special interest in direct and indirect restorations in the posterior dentition, and his dentistry is fueled by his passion for dental photography.

From The Medical University in Lodz (Poland) to private clinics in Malta and London, his dental journey reflects dedication to excellence.

Importance of high-quality prosthodontic treatment

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.

But how is it possible to deliver perfectly fitting, high-quality restorations every time? Among the potential sources of problems with the quality of indirect restorations are common mistakes made in the dental office or laboratory, communication issues and – often overlooked – the use of low-quality dental zirconia.

Zirconia restorations – contemporary and aesthetic dental solution

More than 20 years ago, zirconia entered the dental market as a substitute to metal used for the production of crowns and bridges. Both materials – zirconia and metal – were usually combined with a layer of porcelain, forming porcelain-fused-to-metal or porcelain-fused-to-zirconia restorations. In the years to come, several leading manufacturers of dental zirconia (like Kuraray Noritake Dental Inc.) focused on material improvements. These improvements gradually transformed the original white-opaque framework material into a ceramic material with tooth-like optical and excellent mechanical properties. The latest zirconia variants, available with different levels of translucency and strength, are regarded as the best-possible treatment option in a wide variety of patients and indications by many dental professionals around the world. One reason is that they require just a small or no layer of porcelain. Another is that, with low minimum wall thicknesses, they allow for conservative tooth preparations, while they offer a favourable long-term behaviour – that is, if a high-quality material is used.

Quality differences of dental zirconia

Zirconia product quality may vary depending on various factors such as the purity of the raw materials (not only zirconia, but also alumina and yttria as well as colour additives etc.), the exact chemical composition, the grain size and particle distribution. Every step in the blank production process – from powder compilation to blank pressing and pre-sintering – has an impact on the final quality, i.e., the mechanical and optical properties of the zirconia, too.

Common issues resulting from low-quality zirconia

Whenever there is something wrong with the optical properties of a restoration – with its translucency, its overall colour or the transition from one layer to the next in blanks with a multi-layered colour structure – the problem will become apparent after the final sintering procedure in the laboratory. A remake might be necessary and eventually, the blemish might be identified during try-in, which will most likely have a negative impact on patient satisfaction. The same is true for cases with an improper fit resulting from inhomogeneities in the material structure, for example. What is even worse is an inferior biocompatibility, surface quality, edge stability, flexural strength or fracture toughness. These issues are identifiable only with testing equipment that is very expensive and usually not available in dental laboratories. This means that flaws of this kind usually remain undetected until a real clinical problem – like gingival recession, increased plaque accumulation, higher wear or an early failure that might cause pain and discomfort – occurs.

Overview of potential problems and clinical consequences for patients

Certification and standardization of dental zirconia

That is why specialists have developed an ISO standard (ISO 6872:2015), which describes in-vitro tests every manufacturer of dental zirconia used in Europe or the United States needs to conduct in order to pass FDA approval and receive the CE mark. The described tests are used to measure the flexural strength and fracture toughness, the two probably most important properties determining the long-term behaviour of restorations produced from the material. Every material used in Europe or the United States needs to have passed these tests.

How to avoid placing low-quality dental zirconia restorations in your patients’ mouths

Hence, everyone using this certified dental zirconia should be safe and able to minimize material-related risks. However, the increasing popularity of dental zirconia has attracted the attention of companies trying to have their share of the cake without undergoing the necessary efforts needed to safeguard a high product quality and pass certification. Non-certified products that lack CE marking have one thing in common: they definitely put your business and patient at risk.

So how is it possible to safeguard zirconia product quality from the dental office? The good news is that there are some simple rules available. By following them, you are able to avoid placing counterfeit or low-quality dental zirconia restorations in your patients’ mouths.

Avoid placing counterfeit or low-quality dental zirconia restorations in your patients’ mouths.

Three golden rules to provide your patients with high-quality zirconia restorations:

• Only order restorations that are produced domestically or in a region with the same standards as your own: restorations produced in dental laboratories in China, for example, need to fulfil lower standards (thus lacking CE mark) and might not live up to your expectations.
• Talk to your (domestic) laboratory partner about the source of their zirconia: make sure they are purchasing zirconia from leading manufacturers (e.g. Kuraray Noritake Dental Inc.) via authorized distributors or sellers they really know.
• Avoid deals that are too good to be true: low prices may be tempting, but the final cost of a treatment may be even higher than usual when complications occur.

Long-term impact for patients when using certified zirconia restorations

Making certain that the zirconia placed in your dental office fulfils the highest possible quality standards is an important contribution to long-term patient satisfaction. Even if the initial cost of high-quality zirconia restorations is somewhat higher than that of inferior-quality work, the overall investment may be lower when the restorations last longer and remakes are eliminated. Your happy patients are likely to be more engaged and compliant with oral hygiene regimens as well as loyal, with a positive impact on your reputation and patient base.

Research zirconia options and choose for products from certified manufacturers

If you would like to go one step further, you can even compare certified zirconia variants from several manufacturers and detect differences. Kuraray Noritake Dental Inc., for example, is one of very few manufacturers of dental zirconia carrying out the whole manufacturing process including raw material production in-house. In this way, the company is able to control every step in the procedure and provide for an outstanding product quality – no matter which material variant is selected. With the available portfolio consisting of KATANA™ Zirconia UTML (ultra translucent multi-layered), KATANA™ Zirconia STML (superior translucent multi-layered) and the high-translucent multi-layered HTML PLUS as well as YML (with additional strength and translucency gradation), it is possible to cover virtually every indication.

Case by Dr. Ioannis Memis

Single-shade or two-shade approach? Using modern resin composites, it is possible to treat virtually every patient in need of a direct restoration in an aesthetic way using one of those two techniques. If the defect is rather small, a single shade of composite restorative in a body opacity may be sufficient – especially when the tooth to be restored is in the posterior region. Larger defects and those located in the aesthetic zone may require a combination of two different shades – one as a dentin replacement and one as translucent as enamel – to closely imitate the optical characteristics of the natural tooth.

With CLEARFIL MAJESTY™ ES-2, Kuraray Noritake Dental Inc. offers a complete composite system designed to simplify procedures in bot, the single-shade and the two-shade approach. CLEARFIL MAJESTY™ ES-2 Classic is a typical composite for the single-shade technique consisting of 18 shades offered in a single universal opacity. Shade determination is brightness-based, meaning that the brightness is selected first and the hue and colour saturation in a second step (using the VITA Classical A1 – D4 shade guide). For those who want to skip shade determination completely, CLEARFIL MAJESTY™ ES-2 Universal has been introduced. It consists of only two shades for the anterior and one shade for the posterior region, selectable without using shade tabs. For the two-shade technique, CLEARFIL MAJESTY™ ES-2 Premium is the solution: It allows users to copy natural enamel and dentin layers with a total of seven enamel, seven dentin and four translucent shades. Its exceptional feature: pre-defined colour combinations with one Premium shade combination covering three VITA Classical shades. A natural blending into the environment is achieved with the Light Diffusion Technology in the formulation.

All three versions of CLEARFIL MAJESTY™ ES-2 are compatible with each other and offer the same favourable handling properties. The use of different techniques, shades and opacities is demonstrated using the following patient case.

YOUNG PATIENT WITH MULTIPLE CARIOUS LESIONS

A 24-year-old female patient was referred from undergraduate clinic of Operative Dentistry of the Aristotle’s University of Thessaloniki - School of Dentistry (Greece). Patient presented multiple interproximal carious lesions in need of restorative treatment. In the clinical and radiographic examination, the following defects were identified:

Quadrant 1 (maxillary right):

- Distal lesion on the lateral incisor (Class III)

- Mesial and distal lesions on the first premolar (Class II)

- Mesial and distal lesions on the second premolar (Class II)

- Mesial lesion on the first molar (Class II)

Quadrant 2 (maxillary left):

- Distal lesion on the lateral incisor (Class III)

- Mesial lesion on the first premolar (Class II)

- Mesial and distal lesions on the second premolar (both Class II)

- Mesial lesion on the first molar (Class II)

Quadrant 3 (mandibular left):

- Distal lesion on the first molar (Class II)

- Mesial lesion on the second molar (Class II)

In a stepwise procedure, the teeth were restored with CLEARFIL MAJESTY™ ES-2 either in a single-shade or in a two-shade approach depending on the size of the lesions.

INITIAL SITUATION

Fig. 1. Initial situation: Frontal view.

Fig. 2. Occlusal view of the maxilla.

Fig. 3. Occlusal view of the mandible.

RESTORING THE TEETH IN QUADRANT 1

The six carious lesions in this quadrant were restored in three steps. At first, the focus was on the first molar and second premolar. Opening the larger cavity mesially of the first molar provided access to the smaller lesion on the premolar’s distal surface. After caries excavation and cavity preparation, rubber dam was placed and fixed with a clamp on the second molar. The enamel in the cavities was treated with phosphoric acid etchant for 15 seconds before CLEARFIL™ Universal Bond Quick (Kuraray Noritake Dental Inc.) was applied according to the manufacturer’s instructions. For a morphologically correct designing of the proximal contact point and area, the use of a sectional matrix system with rings was utilized. Both cavities were restored with CLEARFIL MAJESTY™ ES-2 Premium in the shades A3D and A2E. Finishing and polishing of the occlusal surface accomplished with silicon cups and Twist Dia disks on a slow speed handpiece.

In the second step, the distal lesion on the first and mesial lesion on the second premolar were restored in an identical procedure with CLEARFIL MAJESTY™ ES-2 Premium in the shade A3D and CLEARFIL MAJESTY™ ES-2 Classic in the shade A3. A different approach was selected in step 3 for the lesions on the distal part of the lateral incisor and the mesial part of the first premolar. Due to the small size and the all-but-prominent position of the lesions, a single-shade technique using CLEARFIL MAJESTY™ ES-2 Classic in the shade A3 was selected. Between the lateral incisor and canine, a posterior sectional matrix was placed in an upright position and fixed with a wedge to support a proper restoration of the contact point, while both elements were used in the usual way between the canine and first premolar.

Fig. 4. Simultaneous restoration of the mesial lesion on the first molar and the distal lesion on the second premolar with CLEARFIL MAJESTY™ ES-2 Premium.

Fig. 5. Restoration of the distal lesion on the lateral incisor and the mesial lesion on the first premolar with CLEARFIL MAJESTY™ ES-2 Classic.

RESTORING THE TEETH IN QUADRANT 2

For the small disto-palatal lesion on the maxillary left lateral incisor, a single-shade technique with CLEARFIL MAJESTY™ ES-2 Classic in the shade A3 also produced aesthetic outcomes. The four lesions at the posterior region of the quadrant were restored in two steps – one for each pair of proximal lesions – with a combination of CLEARFIL MAJESTY™ ES-2 Premium in the shade A3D and CLEARFIL MAJESTY™ ES-2 Classic in the shade A1.

Fig. 6. A single-shade technique is sufficient to aesthetically restore this small lesion on the left lateral incisor.

Fig. 7. Simultaneous restoration of the mesial lesion on the second premolar and the distal lesion on the first premolar.

Fig. 8. Simultaneous restoration of the mesial lesion on the first molar and distal lesion on the second premolar.

RESTORING THE TEETH IN QUADRANT 3

In this quadrant, only a single pair of proximal lesions needed treatment. A simultaneous restoration procedure was selected once again due to the favourable space conditions. Although the size of the lesion was like those in the posterior region of the maxilla, a single-shade restoration was selected with the use of CLEARFIL MAJESTY™ ES-2 Classic (shade A3).

Fig. 9. Treatment of the lesions in quadrant 3.

CONCLUSION

In the present patient case, several different shades, opacities, and combinations of CLEARFIL MAJESTY™ ES-2 were utilized either in a single- or in a two-shade approach. All combinations and techniques produced good outcomes. As shown in Figure 4, the enamel opacity of CLEARFIL MAJESTY™ ES-2 Premium is visibly more translucent than the universal opacity of CLEARFIL MAJESTY™ ES-2 Classic. Experience shows that enamel shades translucency is highly valuable for aesthetic anterior restorations, while in posterior restorations, the universal shade approach is aesthetically adequate, particularly for medium-sized restorations, as shown in Figure 9. This is clearly an evidence of Light Diffusion Technology which is blending hue and colour saturation to the surrounding tooth structure.

Handling of all selected composite pastes is comfortable: non-sticky, adaptable to cavity walls and allowing precise occlusal sculpting. Polishing with Silicone Cups and TWIST DIA for Composite is easy, quick and leaves a natural gloss on the surface.Dentist:

DR. IOANNIS MEMIS

Postgraduate Student, Operative Dentistry Dept., School of Dentistry
Aristotle University of Thessaloniki, Greece

AWARD WINNING PRODUCT

For the 10th time, the self-etch adhesive CLEARFIL™ SE Protect has been named a Top Product by DENTAL ADVISOR, which announced its choices for dental materials and equipment found by its evaluators to deliver the best practice-based performance in its JAN/FEB 2024 issue.

The publication included CLEARFIL™ SE Protect among honorees in the Bonding Agent Self-Etch category, noting attributes that go far beyond providing a reliable bond.

ABOUT THE PRODUCT

This outstanding toolbox staple is built on the same system of the gold-standard adhesive CLEARFIL™ SE BOND, so it offers excellent bond strength for enamel and dentin. Its MMP inhibiting effect protects the bond from degradation over time and hence supports bond durability. Beyond that reliable bond, it provides an antibacterial cavity-cleansing effect that eliminates the need for the use of a separate cavity cleanser, thanks to the proprietary MDPB monomer it contains.

In short, CLEARFIL™ SE Protect offers you following benefits:

• Fast and simple procedure with low technique sensitivity
• Excellent bond strength for enamel and dentin
• Long-lasting bond strength
• Antibacterial cavity-cleansing effect
• Virtually no post-operative sensitivity

It is also a highly versatile adhesive system that can be used in the context of:

• Placing direct restorations
• As a cavity sealant
• For the treatment of hypersensitive or exposed root surfaces

Among the extended indications are cementation with composite resin cement or core build-up with self- or dual-cured resin materials in combination with CLEARFIL™ DC Activator.

EVALUATION

Its attributes are reflected in the study findings and comments of DENTAL ADVISOR’s editors and consultants, who assessed it over a six-week period during which over 150 restorations were placed. It received a 98% clinical rating by consultants using a 1-5 rating scale.

The practitioners evaluating the product found no post-operative sensitivity. Among their observations mentioned in the online DA report were the fact that the primer and bond wet the tooth evenly. They also considered the antibacterial and fluoride releasing qualities “an added benefit”. On the topic of sensitivity, they mentioned that “CLEARFIL SE Protect is effective in the reduction of sensitivity when placed on areas of recession or similar areas of sensitive tooth structure.”.

ABOUT DENTAL ADVISOR

The Top Product or Preferred Product Awards conferred by US-based DENTAL ADVISOR were initially introduced to help busy practitioners make sense of the numerous new solutions indicated for less invasive techniques, standardised or simplified procedures, ultimately to achieve better outcomes regularly.

DENTAL ADVISOR conducts its practice-based clinical evaluations and product performance tests shortly after product launch, and publishes results annually online to help potential users identify high-quality new dental materials and determine which among them are best suited to fulfill their individual requirements.

For more information visit the website of DENTAL ADVISOR: www.dentaladvisor.com

By Dr. Michał Jaczewski

The durability of a composite restoration depends on many factors. Some are outside the practitioner's sphere of influence and are strongly patient-related. For example toothbrush and toothpaste type, brushing technique, diet, stimulants and hygiene habits all have an impact on the restoration. Following the best finishing and polishing protocol, however, is fully up to the dentist.

Correct polishing aims to remove the oxygen inhibition layer and produce a smooth restoration surface. A properly polished restoration will not absorb staining agents from food, drink or stimulants that lead to discoloration of the composite, ensuring a long-lasting aesthetic result of the restoration.

Polishing the composite is a process to which special attention should be paid. It consists of several steps and principles:

• The use of finishing discs allows for a smooth restoration surface , excess composite to be removed and the final shape to be given to the restoration. It is important to remember to work on a moistened surface with a maximum speed of 5,000-10,000 rpm on a 1:1 dental handpiece.

• Polishing rubbers, there are many types and shapes on the market. One of the most universal designed specifically for composite is TWIST™ DIA for Composite. This is a set consisting of two rubbers with different levels of abrasion. The first (dark blue) is used for preliminary rough polishing, the second (light-blue) for final gloss and smoothness. It should be remembered that working with these tools should be carried out on a dry surface without water cooling. Dry working carries the risk of irritating the dental pulp, so the working speed should be limited to between 5000 and 10000 rpm and excessive pressure must be avoided.

• The next step is to use a diamond polishing paste with a gradient of 1 to 5 microns. The use of a polishing goat wheel brush is recommended to use with this paste. The type of brush is not important, however, don’t use rigid bristles that could scratch the composite. Using the polishing brush and polishing paste make it possible to reach places which are difficult to access, such as the cervical area and proximal surfaces. In addition to this step, a celluloid diamond containing abrasive strip is used to polish the proximal surfaces more precisely. In order not to alter the contact points, low abrasive (Super Fine) strips should be used.

• A further step to increase the gloss of the restoration and to protect it against discoloration is an aluminum oxide paste with a cotton polishing brush. The use of such paste, originally dedicated to ceramics, results in an exceptionally smooth surface and a high gloss of the restoration surface. This step is carried out in a dry environment at a maximum speed of 5,000-10,000 rpm.

In all techniques, thus also the Flowable Injection Technique, the level of polishing influences the durability and the optical and aesthetic properties of the restoration. This key step in tooth restoration should therefore devoted sufficient time. Composites are characterized by different compositions and amounts of fillers which not only influence their properties, but also the ease with which they can be polished. In some cases, the procedure has to be repeated several times to achieve a "mirror effect". CLEARFIL MAJESTY™ ES Flow is a composite which is very easy to polish to a high shine level, despite its high filler content. Specially adapted rubbers, brushers and pastes enable easy creation of a smooth surface thereby contributing to a lasting result.

BEFORE

AFTER

3-YEARS RECALL

MAKE THEM SHINE, MAKE THEM SMILE!

Would you like to know more about Flowable Injection Technique? Read the insightful and inspirational interview with Dr. Michał Jaczewski.

Dentist:

MICHAL JACZEWSKI

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