429 Too Many Requests

By Dr Alessandro Devigus

Close up of insufficient crown on tooth 11.

After removal of old crown – discolored stump (endo treatment).

Try-in of the crown after sintering – no intrinsic fluorescence.

Try-in of the crown after glazing.

Try-in of the crown after glazing under cross polarized light to check the shade match.

Try-in of the crown after staining under cross polarized light to check the shade match.

Retraction cord in situ for adhesive cementation with PANAVIA™ V5.

Adhesive cementation using PANAVIA™ V5 opaque to mask dark stump.

Control after 1 week.

Control after 1 week – cross polarized light to check shade.

Control after 1 week – fluorescence check.

FINAL SITUATION

Dentist:

Dr Alessandro Devigus received his degree from Zurich University, Switzerland, in 1987. Since 1990 his working in his own private practice with a focus on CAD CAM and Digital Dentistry. He is also CEREC Instructor at the Zurich Dental School.

Dr Alessandro Devigus is an active member of the European Academy of Esthetic Dentistry (EAED), founder of the Swiss Society of Computerized Dentistry, Neue Gruppe member, ITI fellow and speaker.

Dr Devigus is editor-in-chief of the International Journal of Esthetic Dentistry, author of various publications and an international lecturer.

When it was first introduced to restorative dentistry in the early 2000s, zirconia was an opaque, unnatural-looking substance with a chalk-like whiteness. Two decades later, technological and material advances have meant that zirconia is now a highly aesthetic and durable ceramic solution for a variety of procedures. Leading the way is Kuraray Noritake Dental’s KATANA™ Zirconia series, which can now be integrated at every step of the restorative workflow.

The pioneering nature of KATANA™ Zirconia

Key reasons for zirconia’s improvements as a dental material are continued innovations in the powder that forms the basis of the discs. While a majority of dental zirconia manufacturers rely on a single shared provider of powder, Kuraray Noritake’s zirconia materials are unique in that they are produced in an end-to-end in-house process. From the proprietary powder technology through to disc pressing and pre-sintering, KATANA™ Zirconia is produced to ensure unparalleled purity and unmatched quality.

Multilayered technology

Three of the four types of KATANA™ Zirconia—UTML, STML and HTML—incorporate Kuraray Noritake’s original multilayered build-up technology. This innovative four-layer structure faithfully replicates the translucency and colour gradation of natural dentition, resulting in an eye-pleasing final restoration. Furthermore, each member of the KATANA™ Zirconia series possesses different translucency and mechanical properties, allowing clinicians to cover a wide range of anterior and posterior restorations.

A zirconia series embedded in a system of products

Thanks to Kuraray Noritake’s emphasis on research and development, the KATANA™ Zirconia family is embedded in a complete system of products for polishing, staining, glazing, porcelain veneering and cementation in order to deliver outstanding treatment outcomes.

CERABIEN™ ZR FC Paste Stain allows for the easy characterisation of full-contour zirconia restorations. Available in 27 different shades, it delivers an extremely controllable transparency that enables the creation of highly aesthetic restorations.

When cementing a zirconia restoration during the trial fitting stage, the new KATANA™ Cleaner will surely come in handy. This non-abrasive universal cleaner from Kuraray Noritake helps to remove contamination, thereby delivering the bond strength patients deserve. Its relatively low pH value of 4.5 also means that, unlike other dental cleaners, it can be used both intra-orally and extra-orally.

Of course, when finally cementing the restoration, the dentist needs to be confident that the cementation will be both reliable and durable. PANAVIA™ V5 is Kuraray Noritake’s strongest cement yet and offers unrivalled procedural simplicity and predictability. This amine-free paste is available in five different shades that have been scientifically demonstrated to exhibit less post-polymerisation colour variance than amine-based cements. For aesthetic and stable cementation, PANAVIA™ V5 is the best option.

It is clear that, with the translucent KATANA™ Zirconia series and these associated products, Kuraray Noritake has established a fully integrated system that can work for almost any prosthetic workflow. KATANA™ Zirconia is key to durable metal-free restorations.

By Dr Salvatore Scolavino and DT Francesco Napolitano 

The dental laboratory is confronted with the greatest aesthetic challenge whenever it comes to the restoration of a single incisor with natural adjacent teeth. In the following case, a young patient had undergone endodontic treatment of her tooth 21 (fig. 1) while all other teeth showed their natural appearance. Tooth 21 was due for replacement now (fig. 2).

Fig. 1:  X-Ray after endodontic treatment (with new crown on tooth 21 in place).

Fig. 2: The former restoration with which the patient showed up in the dentist’s practice.

To keep the natural identity, together with preserving the gingiva outline, the decision was taken in favour of a monolithic zirconia restoration, with a layered block for a full-contour crown. KATANA™ Zirconia STML (Kuraray Noritake Dental) provides for four gradational layers from „Body/Dentine“ (cervical area) to „Enamel“ (incisal aera), varying in chroma and translucency. Using this kind of milling block, it is possible to imitate the natural progression from yellowish to whitish-blue, and this in an easy manner. At the same time this way, the endodontic post wouldn’t shine through and make any aesthetic difference. On the other hand, the zirconia irradiates into the gingiva and results in a natural looking shade allover the anterior area. Furthermore for a lively and most natural-identical appeal, it was intended to individualize the crown by surface stains. With the product CZR™ FC Paste Stain by Kuraray Noritake Dental, 27 shades are available, together with fluorescence. What is essential in the front, too, is this well proven experience: All zirconia material enhances the close gingival attachment and provides for stable results of the pink-and-white aesthetics.

The dentist built up the stump 21, prepared it according to the specifications for zirconia and took the impression (fig. 3). The plaster model followed (fig. 4) and was scanned to start then the digital process. After designing, the crown was milled and tried-in at the next session with the patient (fig. 5).

Fig. 3: Impression taking after preparing tooth 21.

Fig. 4: Plaster model - the prothetic baseline of the case.

Fig. 5: Try-in of the zirconia crown in the patient’s mouth with rubber dam.

SHAPE AND COLOUR

Right when starting the case, the teeth of both jaws had been scrutinized: first for shape. Special attention was payed to the interproximale space between 11 and 21 because this area had worn out in the meantime (see again fig. 2). It was also necessary to move closer to each other the approximale margins 21/22 resp. 11/12 in their cervical-middle parts. When giving the zirconia crown its final shape, this resulted in a widely swinging outer line distally 21. For harmony reasons, tooth 11 was extended distally, too. Here, the clinician used the direct filling composite CLEARFIL MAJESTY™ Classic, shade A2 (fig. 6, 7 and 8). This nano-hybrid composite by Kuraray Noritake Dental is easy-sculpting and integrated fully with the milled crown.

It was most important for crown 21 and tooth 11 too, to create a 3D effect of the tooth structure and an age-appropriate vestibular surface texture. For this, the characteristics of the adjacent teeth and allover both jaws were examined meticulously in general and in detail. Surface burs, discs, stones, and similar instruments sophisticatedly engraved pericymatia and a groove here and there, thus accomplishing the perfect natural look.

Fig. 6: Tooth 11 before recontouring the shape distally.

Fig. 7: Finished crown 21 on the plaster model. Notice: In order to match the shape of crown 21 and close-up the margins 11/12, composite has been added in the interproximal space.

Fig. 8: Finishing the new distal outline of tooth 11.

The final colour touch was given to both teeth by surface staining: with a thin layer of FC Paste Stain measuring only 50-70 micrometers in depth, different shades were applicated. The entire range was used from yellow/orange to blue and white (fig. 9a-d) in order to provoke the effect of mamelons and other structures in all thirds of the restorations.

Fig. 9a: Definitive fitting of the restoration.

Fig. 9b: Directly after the fitting.

FINAL SITUATION

Fig. 9c: View of the lips with the restoration in place.

Fig. 9d: Natural look of the upper and lower jaws.

By Daniele Rondoni, RDT

Hybrid designing meets the functional needs in term of lower abrasiveness and higher toughness.

Step 1
Zirconia Frame (KATANA Zirconia HTML A2) cut-back designed to minic anatomical dentin structure and incisal frame.

Step 2
Application of Internal Stain.

Step 3
Completion of Internal Stain firing.

Step 4
Application of Luster, Clear Cervical and Opacious Body.

Step 5
Completion of firing.

Step 6
Completion of glaze (self-glaze) firing.

Step 7
Polishing of lingual side.

Step 8
Post-operative view.

4-Years Post-operative.

Mind the Gap!

Webinar about the key factors which influence the gap between the margin of prepared tooth and restoration, also about accuracy evaluations of milled materials and resin cement removal techniques during cementation.

Dr JOSEF KUNKELA, DMD, PHD

1993
Dentistry graduate of First Medical Faculty of Charles University, Prague, Czech Republic

1995
Fellow in Medical Faculty of Charles University Prosthodontic Department in Hradec Králové, Czech Republic

1999
Gained Second Degree Specialization in Prosthodontics

2001
Named external teacher of the Prosthodontic Department at the Charles University Clinic of Dentistry in Hradec Králové and Palacky University in Olomouc, Czech republic

2009
Named president of Czech Society of CAD/CAM Dentistry

2010
Founder of KUNKELA Campus, International CAD/CAM Traning Center in Jindrichuv Hradec, Czech Republic (Certified Exclusive DentsplySirona Training Center)

2018
Finished postgraduate doctoral degree PhD, thesis Dental Office Management and Marketing (University of Economics Prague)

Certified CEREC trainer by the International Society of Computerized Dentistry (ISCD)

Member of DSD (Digital Smile Design) Master Team

Member of MicroVision Group

Member of SKYN Concept Team

Member of Academy of Digital Dentistry

Board Member of ADDA (Association of Digital Dentistry Academies)

Ambassador of DDS (Digital Dentistry Society)

CEREC Beta Tester

CEREC Guide Beta Tester

CEREC Advocate

Key Opinion Leader in the area of digital dentistry

International speaker at the field of Digital Dentistry, Guided Implantology, Management & Marketing

By Drs. Mart Ramaekers

A 20-year-old patient was dissatisfied with her discolored composite restorations on her maxillary central incisors and the right lateral incisor. The original restorations had been placed after an accident with traumatic dental injuries approximately five years ago. We went through all available options that would enable us to improve the aesthetics of her anterior teeth and finally opted for replacement of the existing restorations by new direct restorations made of composite resin.

Prior to the restorative procedure, a home bleaching procedure was carried out with Opalescence 10% (Ultradent). In addition, a palatal silicon index was produced to record the shape and morphology of the existing restorations and dentition.

Initial situation

Frontal view of the initial situation.

Lateral view: The discolorations are particularly visible on the maxillary right central and lateral incisor.

Close-up view of the upper anterior teeth.

The existing restorations were removed after the administration of local anesthesia. Then, labial and palatal bevels were created, followed by sandblasting of the prepared tooth structure with alumina (50 μm). Hereafter, the enamel was etched for 30 seconds (K-Etchant Syringe, Kuraray Noritake Dental), before the primer and bond of CLEARFIL™ SE BOND (Kuraray Noritake Dental) were used according to the instructions.

Build-up of the palatal walls with a first increment of ‘enamel’ composite (CLEARFIL MAJESTY™ ES-2 Premium A2E, Kuraray Noritake Dental) using the silicon index.

Creation of the mesial and distal marginal ridges in A2E enamel composite. The procedure was facilitated by the vertical placement of sectional matrices (Contact Matrices Stiff Flex Large, Danville) in the interproximal space.

Creation of the dentin core and the dentinal mamelons by placement of an opaque composite increment (CLEARFIL MAJESTY™ ES-2 Premium, A2D). It increases the opacity in the middle third of the restoration.

Filling of the space between the mamelons with translucent composite (CLEARFIL MAJESTY™ ES-2 Premium, Translucent Clear).

Labial finishing of the restorations with a layer of semi-translucent composite (CLEARFIL MAJESTY™ ES-2 Premium, A2E).

Application of glycerin gel on top of the last layer of composite to prevent formation of an oxygen inhibited layer during the final light-curing procedure. Final contouring and polishing were performed by using red (fine) and yellow (x-fine) finishing diamonds followed by high gloss polishing with CLEARFIL™ TWIST DIA (Kuraray Noritake Dental).

Final situation

Frontal view of the final situation.

Lateral view: No shade differences or restoration margins are visible.

Close-up view of the new restorations on the upper anterior teeth.

Ceramist:

Drs. Mart Ramaekers

Academic education
2002 - 2007   Tandheelkunde, Radboud Universiteit Nijmegen

Non-academic education
2013 - 2014   Academy of Reconstructive Dentistry, Beuningen
2019              Biomimetic Dentistry, Los Angeles

Career
2008 - 2013    Mondzorg Jekerdal Maastricht
2013 - 2015    De Drietand Maastricht
2009 - 2020    Amalia Kliniek Kerkrade
2020 - now      Espenbos Kliniek Cadier en Keer

Materials used: Kuraray Noritake Dental: CLEARFIL™ SE BOND 2, K-Etchant Syringe, CLEARFIL MAJESTY™ ES-2 Premium Enamel A2E, CLEARFIL MAJESTY™ ES-2 Premium Dentin A2D , CLEARFIL MAJESTY™ ES-2 Premium Translucent Clear and CLEARFIL™ TWIST DIA. Heavy Putty (Provil Novo, Heraeus Kulzer), Glycerine gel (K-Yelly Johnson&Johnson), Rubberdam non-latex Heavy (Sigma), Contact Matrices Stiff Flex Large (Danville), Optragate Regular (Ivoclar)

Phosphoric acid is not only used for etching enamel and dentin surfaces within dental bonding procedures, but also frequently as an intra- and extra-oral cleaning agent for tooth structure and dental restorations. But is phosphoric acid always the right choice?

Direct Restorations

Many bonding procedures are performed using self-etch adhesive systems. When applied to the prepared tooth surface, the acidic monomers in the primer and/or the bond partially remove and modify the smear layer, resulting in a thin hybrid layer. A substantial amount of hydroxyapatite crystals remain on the slightly etched surface, enabling both chemical and mechanical adhesion between the adhesive and the dental tissue. If the bonding surface in the cavity is contaminated e.g. with blood or saliva, and phosphoric acid is applied for cleaning and decontamination, it etches the tooth structure, too, resulting in the removal of HAp. This will prevent the desired chemical adhesion, between the bonding system and the tooth, which may lead to compromised bond strength. Hence, cleaning with phosphoric acid may have a negative effect in this context and cannot be recommended.

Great cleaning results with no negative effect on the performance of the dental adhesive are obtained with the universal cleaning solution KATANA™ Cleaner. It contains an MDP salt of triethanolamine (MDP-TEA), as well as 'free' MDP. With a pH of 4.5, KATANA™ Cleaner is essentially neutral, meaning that, unlike phosphoric acid, it does not remove hydroxyapatite from the tooth. However, it does still effectively eliminate any saliva and/or blood contamination.

Indirect Restorations

For materials containing glass, such as lithium disilicate and feldspathic porcelain, phosphoric acid is a tried-and-tested agent for removing contamination, such as deposits produced when etching these materials with hydrofluoric acid. However, routine use of phosphoric acid to remove contamination from indirect restorations may not be wise. In fact, its use on zirconia is not recommendable, as it could inhibit the desired chemical adhesion of phosphate monomers in the bonding agent to the surface of the zirconia restoration.

When cementing prosthetics using self-adhesive resin cements like PANAVIA™ SA Cement Universal or cements that use self-etching primers (e.g. PANAVIA™ F2.0 or PANAVIA™ V5), the use of phosphoric acid on dentin is not recommended for the same reasons as in the case of direct restorations.

No pitfalls, no restrictions

Unlike 35% phosphoric acid, KATANA™ Cleaner is a product that cleans reliably without inducing negative side effects – independent of the type of tooth structure, kind of restorative material and planned bonding procedure. Hence, it is a universal cleaning solution that allows you to streamline your procedures.

CERABIEN™ ZR
High translucent and opal porcelain for True-to-life, highly aesthetic restoration.

Blue-tinged light translucency at incisor edge of enamel was reproduced with LTx and LT Royal Blue.

Initial situation.

LTx and LT Royal Blue were used at the incisor edges to reproduce the bluish opalescence and translucency effect.

Step 1: Build-up of internal structures.

In order to reproduce the mamelon structure with stain and dentin color, Internal Stains were applied, then baked.

Step 2: Applied the first Internal Stain, then baked it.

In order to reproduce the stain in the internal enamel structure, Luster porcelains were applied and baked as a base.

Step 3: Applied the first enamel structure, then baked.

In order to reproduce the white spot and the incisor halo, Internal Stains were applied before baking.

Step 4: Applied the second Internal Stain before baking it.

To reproduce the subtle color and translucency of enamel, Luster porcelains were applied before baking.

Step 5: Applied the second enamel structure before baking it.

Step 6: Final situation.

Photos: Courtesy of Otani Dental Clinic, MDT Ryuzo Shiba and MDT Naoto Yuasa.

New liquid ceramic FC Paste Stain for full-contour solutions with KATANA Multi-layered Zirconia - Features and 3D-technique.

ROBERTO ROSSI 

"YOU CAN’T STOP THE WAVES, BUT YOU CAN LEARN TO SURF"

Born in Savona in 1989, he studied and got his diploma at “Mazzini” Dental School, the one dental school in his hometown, and he still lives there. In 2007 he was awarded the National Award for Best Dental Technician in Turin. Since 2008 he has been working at Daniele Rondoni’s Dental Lab and he is now in charge of the aesthetic planning of dental restorations. He shares this task with Master Dental Technician Daniele Rondoni, with whom he decides which strategy and materials – composites or ceramic especially – to opt for. In 2011 he coauthored with Mr. Rondoni “Sei faccette additive in composito” (Six additional composite facets), an article published in Dental Labor, 5/2011. A teacher at NISC, Noritake Italian Study Club since 2014, he is also a teacher at the AAT Community College – a reality he feels especially attached to – and he is in charge of the photographic services and social network profiling of the lab.

When art meets technology;
Logical evolution of design and techniques: Microlayering with Kuraray Noritake new porcelains. 

DANIEL RONDONI
Born in Savona in 1961, he lives and works in his hometown where he has been the manager and director of his own laboratory since 1982.