A clinical case created by Dr. Shoji Kato of Takanawa Dental Office, Japan

PRODUCTS USED IN THIS CLINICAL CASE

KATANA™ Zirconia Multi-Layered Series

Our KATANA™ Zirconia series brings naturalness to all
prosthetics. Make natural veneers and natural full contour
prosthetics out of zirconia. Plus large dentin-like frameworks.
KATANA™ Zirconia UTML is a high translucent disc, which meets
the requirements of highest translucency level for anterior crowns
and veneers. All layers are highly translucent, whereby the color
saturation is reduced in the incisal area. The transparency of the
natural enamel is copied and the abutment shade is absorbed.

KATANA™ Zirconia STML is a multi-layered zirconia disc
where light is transmitted in the incisal area and blocked in
the cervical area. Due to its color and translucency gradient,
more opacity in the cervical area and more translucency in the
incisal area are achieved.

KATANA™ Zirconia ML, the pioneer of zirconia with a
natural color gradient, is made for large dentinal frameworks.
Its natural opacity makes it the ideal base to cover it with
hand-made ceramics. 

PANAVIA™ V5
One Cement. All cement indications. One prime procedure.
Start with priming the tooth using PANAVIA™ V5 Tooth
Primer. Then prime and roughen the prosthetic using
CLEARFIL™ CERAMIC PRIMER PLUS and apply the pre-mixed
cement. PANAVIA™ V5 comes in five aesthetic shades and
the original MDP assures a durable bond. On the tooth and
the prosthetic.

CLEARFIL™ CERAMIC PRIMER PLUS
The universal prosthetic primer for almost all prosthetic surfaces.
It durably bond to ceramics (lithium disilicate, zirconia), hybrid
ceramics, composite resins and metals. The original MDP monomer
bonds to metals and metal-oxides such as zirconia. Silane coupling
agent γ MPS guarantees a strong adhesion to composites, glassceramics
and hybrid ceramics. This perfect mixture of ingredients
will give you long lasting adhesion to virtually all dental materials.

By Paul de Kok, Amsterdam (KVPA) Periodontic Clinic & ACTA

Picture 1

The Patient
Joris reported to the clinic with two discoloured composite two discoloured class IV composite restorations in tooth 11 and 21 11 and 21 (picture 1). These vital teeth were traumatized in his childhood. He was not satisfied with the aesthetics of the restorations neither with the overall shape and colour of the two teeth. It was therefore decided to make porcelain facings for tooth 11 and 21.

Picture 2

The preparation
In order to limit the sacrifice of healthy tooth tissue while still creating sufficient space for the porcelain, a preparation was chosen with an incisal reduction of 1.5mm and a buccal reduction of 0.5mm. A so-called depth cutter – a diamond drill with 0.5mm deep recesses – was used to achieve this (picture 2).

Picture 3

To be able to adjust the shape of the mid-line to the new facings, cutting was carried out centrally through the contact. From the distal aspect the contactpoint was remained. The thin shoulder was positioned equi-gingivally, so that a dry operative field could be achieved without damage to the gingiva.

The preparations were then finished using fine drills and polishing discs. The existing, well bonded diamonds composite restorations were left in situ (picture 3).

Picture 4

Since the transparent facings are very thin, the colour of the cut teeth is significant. The colour of the cores was therefore matched using the Natural Die colour guide (picture 4). Finally, impressions were made. Temporary restorations were placed by means of 4 spot etching points and bonding.

Picture 5

Cementation
To combine superior aesthetics with adequate strength, pressed lithium disilicate restorations were chosen for Joris. Prior to cementing the facings, they were tried for size and checked for marginal integrity, contact points, occlusion/articulation and aesthetics. Then the correct cement colour was established by testing the facings with various try-in colours PANAVIATM V5 Universal (A2); Universal (A2) appeared to be the most appropriate colour in Joris’s case. The teeth were then polished with pumice and the facings were cleaned with alcohol, after which the teeth from 14 up to and including 24 were isolate by a rubber dam.
An incisor clamp was placed on the first teeth to be cemented. The facing was tried for fitting once more to ensure that it was free of contact with the rubber dam or the clamp and that the operative field of the preparation was totally dry (picture 5).

Picture 6

The facing was etched with 9% fluoricacid (picture 6) for 20 seconds to achieve micro-mechanical retention.

Picture 7

It was then rinsed with water for 20 seconds before being neutralised in a solution containing ceramic neutralising powder. CLEARFILTM CERAMIC PRIMER PLUS was then applied to the facing. This ensures chemical bonding between the facing and the composite cement thanks to the incorporated silane and MDP. The adjacent teeth were separated by means of a transparent strip, after which the preparation was etched with 35% phosphoric acid (picture 7). TOOTH PRIMERTM was applied after thorough rinsing with water and drying after it had taken effect for 20 seconds.

Picture 8

A thin layer of PANAVIA V5 cement was then applied to the facing. The facing was placed on the preparation with the application of light finger pressure. A microbrush was used to remove the major excess along the margins. The cement of the buccal and palatal aspect was light cured for 5 seconds. A sharp scaler and floss were used to remove the final excess. Glycerine gel was then applied to the outline to avoid oxygen inhibition during curing. The cement was finally light cured from both sides for 20 seconds, the glycerine gel was rinsed away and the margins were finished by means of a composite polishing stone. After placement of the first facing, the rubber dam clamp was moved to the neighbouring tooth so the cementation of the second facing could proceed. This facing was once more tried for fit, pre-treated and cemented in an identical manner (picture 8).

Picture 9

The result
The facings were checked a few weeks later (picture 9). Joris was very satisfied with the aesthetics of his two central incisors. The transitions from tooth to restoration were invisible and the gingiva was healthy.

Picture 10

The transparency, surface structure and gloss are better adjusted to the neighbouring elements and to Joris’s smile (picture 10).

Dentist:

Paul de Kok, Amsterdam Periodontics Clinic

Paul de Kok studied dentistry at the ACTA and is an authorised restorative dentist at the Amsterdam Periodontic Clinic (KvPA), where he treats referred patients with restoration and aesthetic issues. In addition, Paul teaches indirect restorative dentistry at the Oral Functional Anatomy faculty of ACTA as well as conducting research in the Materials Science department. He also delivers lectures about this discipline at both a national and international level.

Dental technician: Eric van der Winden, Oral Design Center Holland

PAUL DE KOK USED CLEARFIL CERAMIC PRIMER PLUS AND PANAVIA V5 FOR HIS CASE STUDY

Adhesive cementation of high-translucent zirconium oxide restorations

The definitive integration of full ceramic restorations throws up a lot of questions in everyday practice life. Many of these are answered in the “ACTA Report”. The Congress lectures (ACTA Congress) held by Prof. Matthias Kern (Kiel/Germany) and Daniele Rondoni, ZTM (Savona/Italy) have been condensed down to the essentials and presented in a practical manner. The focus is placed on zirconia materials and it’s adhesive, MDP based cementation.  

Until now, the preferred cementation method for dental zirconia was conventional luting. Through the establishment of high-translucent zirconia materials (e.g. KATANA^TM UTML/STML, Kuraray Noritake Dental), however, the standards have changed. The outstanding aesthetic properties of the new zirconias are to be supported through a composite resin cement. In the ACTA Congress held at the ACTA University (Amsterdam/Netherlands,), Prof. Matthias Kern and Daniele Rondoni, ZTM evinced exciting information on the subject. Prof. Kern underlined the significance of the MDP monomer for the reliable adhesive cementation of zirconia restorations. He is convinced that the chemical adhesion can only take place using MDP based resin cements (PANAVIA^TM, Kuraray Noritake Dental). Rondoni presented the advantages and the material properties of the new zirconias.

In the “ACTA Report”, the scientifically founded explanations, which have proven their worth in practice, have been summarised. The reader learns for example which prerequisites are required for adhesive cementation. In addition, valuable preparation and material-relevant processing guidelines are provided. The explanations on the functional method of the adhesive cementation and the MDP monomer are presented in an interesting way. The original MDP monomer was developed in 1981 by Kuraray in order to improve the bond strength on tooth structure and dental metal alloy. Today, MDP monomer (the basis of PANAVIA^TM resin cements) are characterised by their strong adhesion to metal(oxides) incl. zirconia.

PANAVIA^TM V5 is an aesthetic and adhesive resin cement for all cementation indications, based on MDP technology. Prof. Kern published a work on bonding to zirconia ceramic with MDP for the first time in 1998. His well-founded experiences are practically summarised in the “ACTA Report”.

Today sandblasting and MDP is the proven formula to reliable adhesive cementation of zirconia.

The “ACTA Report” is a recommended read for all dentists and dental technicians who have integrated full ceramic restorations into their everyday working lives. Well-founded and practical!    

For more information

Email dental.eu@kuraray.com or phone +49-(0)69-305 85 980

You can read the full report  here.

PRESS RELEASE

EXPERTS PRESENT IMPORTANT FINDINGS ON THE ADVANCED BONDING PROPERTIES OF THE NEW ONE-BOTTLE UNIVERSAL ADHESIVE: CLEARFIL™ UNIVERSAL BOND QUICK

Hattersheim, Germany – January 2017  

The 2nd December 2016 saw the annual Kuraray Noritake Expert Symposium in Frankfurt with more than 60 leading adhesives and composites experts from universities all over Europe meeting to discuss and share new advances in the world of adhesive technology, notably CLEARFIL™ Universal Bond Quick: the new one-bottle universal adhesive by Kuraray Noritake Dental which is to be launched in Europe in February. Prof. Dr. Bart Van Meerbeek from the KU Leuven - BIOMAT - University Hospitals Leuven/Belgium, acted as Symposium Moderator.

Starting off the day’s proceedings, Yusuke Fujimura, Technical Manager and Chief Developer at Kuraray Noritake Dental demonstrated how, unlike most other bonding agents, CLEARFIL™ Universal Bond Quick works instantly, removing the need for waiting time, extensive rubbing or multiple layer application. This was followed by Professor Dr Bart Van Meerbeek who discussed the problems associated with conventional total-etch methods whereby strong phosphoric acid is applied to the dentin, dissolving the natural tooth protector hydroxyapatite and exposing the collagen matrix. He posed the fundamental question:” Why demineralise the tooth with strong acids only to remineralise it again?”

Also on the agenda were four individual studies, each tested far over and above the legally-required ISO standards, providing insights into the fact that the longevity prognosis for bonded restoration is absolutely dependent on both the quality of the adhesives and the effect of the procedural steps. Luc Randolph, Materials Research Engineer at the University of Louvain-la-Neuve/Belgium, reported on shear bond strength tests using the new universal adhesive CLEARFIL™ Universal Bond Quick concluding that: “Among the all-in-one universal alternatives, the new CUBQ technology appears equally efficient despite the absence of waiting time after application, making it a more user-friendly and convenient option than its competitors.”

Prof. Dr. Amélie Mainjot from the University of Liège/Belgium went a step further demonstrating highly positive bond results for zirconia which showed, even after thermocycling, comparable bond strength to Vita Mark II class-ceramic instead of pre-test failures when not treated with CLEARFIL™  Universal Bond Quick.

Finally, Prof. Dr. Mutlu Özcan from the University of Zurich/Switzerland, concluded that, whereas the described method of air-abrasion increases the adhesion results for the majority of adhesives, air-abrasion may not be needed for CLEARFIL™ Universal Bond Quick.

Over the course of the day the speakers presented many enlightening research results which participants were able to take away with them. However, before they left, Prof Van Meerbeek called for a panel discussion so that speakers could collaborate with the audience on requests for future development and findings.

CLEARFIL™ Universal Bond Quick is launched in Europe on the 1st of February 2017. 

Read the full report: Kuraray Noritake Symposium Report (PDF: 360 Kb)

Kuraray celebrates its 90th anniversary in 2016. We take the opportunity of this occasion to offer you a glimpse of the history of Kuraray from a new perspective. The name Kuraray represents more than 8,300 employees and an annual turnover of approximately 3.7 billion euros. Kuraray was founded in Kurashiki, Japan, in June 1926, by Magosaburo Ohara. Kuraray began with the domestic production of Rayon, a synthetically produced cellulose fibre referred to as artificial silk, a new and innovative product at the time. 

The name KURARAY is derived from the location: Kurashiki and the product manufactured: Rayon. The development of this branch of production developed very quickly in Japan, with many other major manufacturers establishing themselves during this period. Whereas others recruited their technicians and experts from elsewhere, Kuraray established the Kyoko Research Laboratory, which was managed by the University of Kyoto to generate expertise and support for the development of the required technologies. Ohara also committed himself to cultural and social projects. The building of an art gallery and the financing of an orphanage represent only two of his many projects in Kurashiki. The Ohara Museum of Art was the first private museum of Western art in Japan.

Ohara considered the dreadful conditions in which employees commonly worked and lived at the time to be unacceptable; he was not a profit-driven employer, and attempted to solve such issues. He ensured that decent accommodation, fitness facilities and nursery schools were built to provide young employees, or families who had left their homes to work for Kuraray, with everything they needed for education and a healthy and culturally rich lifestyle.
One of the largest general hospitals in the west of Japan, the Kurashiki Central Hospital, was originally founded by Kuraray to promote the well-being of employees and their families. It is still considered to be one of the most famous hospitals in Japan.

With the production of Kuralon in 1950, developed from the in-house manufactured products PVA and vinyl acetate, Kuraray expanded to become the specialist chemical company it is today. Always intent on making a contribution to the good of society, Kuraray addressed the subject of environmental protection very early on. The visionary Ohara was aware of the seriousness of environmental pollution, and made great efforts to prevent it.

Internationally too, Kuraray has remained aware of its social responsibilities. After the war, a production facility was opened in China which helped to improve the poor post-war living conditions of the Chinese population.
Today, Kuraray is a leading global manufacturer of the specialist chemicals used in many aspects of daily life. Kuraray has always viewed its employees as its most important asset, and continues to do so to this day.

During my presentations I am often asked why clinical research into bonding systems is conducted using class V situations.

The non-carious class V lesion is most suitable for this type of research for a number of reasons. Unquestionably, the main reason is the fact that such lesions present little or no macro retention. It must be remembered that if a cavity presents macro retention, loss of adhesive strength in the bonding interface will not automatically lead to loss of retention.

Other major reasons (in no particular order) are that such lesions occur relatively often, but also that in general they are situated in an easily accessible area and do not demand complex restoration technology. The configuration factor is low (ratio between free and bonded areas) and does not therefore cause much shrinkage stress. In addition, both enamel and dentine are involved in the restoration, although in some studies efforts are made to limit bonding to enamel (for example, in Van Dijken et al., Clinical long-term retention of etch-and-rinse and self-etch adhesive systems in non-carious cervical lesions. A 13 year evaluation. Dent Mat 2007).

The restoration is then re-assessed periodically. Obviously, loss of retention is considered, and sometimes restorations are also assessed on marginal integrity, marginal discolouring and aesthetics.

Whenever a restoration goes wrong, this is noted as a failure. The survival/lifetime of restorations is expressed in an Annual Failure Rate; for example, an AFR of 4.6 means that, on an annual basis, 4.6% of the restorations failed in the course of the study.

Phosphoric acid, sometimes also called orthophosphoric acid, is a substance that is used frequently in the practice of dentistry, mostly in concentrations between 30 and 40%. It is a proven substance for the etching of enamel (Buonocore 1955). It also entails hazards, because contact with the eyes and skin may cause severe irritation, blistering and burns.

The substance should only be applied where its use is intended, and proper control is of the essence. The use of a coloured gel is therefore recommended, preferably of a thixotropic type. The application of a cofferdam is also definitely recommended, and the patient should wear protective glasses ( the practitioners should obviously also wear protective glasses). When removing the etching gel, the main volume should first be sucked away using a saliva ejector without a cap. The area should then be rinsed clean with a spray mist suction device under continued suction.

If the etching gel should unintentionally get onto the skin or, even worse, into the eyes, the affected area should be rinsed with plenty of water until the patient no longer feels any pain in the affected area. In such a case, it is recommended that medical assistance be sought.

This article is based on a publication in the British Dental Journal Vol 217 No.2 Jul 25 2014
Link to the publication. 

I would like to refer to a recently conducted study by Garcia et al. to reply to this question, which derives from practice. The study examines the effect of three desensitisers on the bonding strength to dentine of a composite cement.

The study concluded that the effect is dependent on the material. Gluma Desensitizer (Heraeus Kulzer) and Super Seal (Phoenix Dental) decreased the bonding strength, whereas TeethmateTM Desensitizer (Kuraray Noritake) improved the bonding strength. The researchers obviously consider it necessary to conduct further research into the workings of TeethmateTM Desensitizer, a cement that contains calcium phosphate.

Clinical significance:

TeethmateTM Desensitizer, a material containing calcium phosphate, may serve as a useful new generation of desensitisers for use prior to the cementing of indirect restorations.

Click here for the research abstract.