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Yhdistelmämuovisen restauraation tekeminen on yleisin hammaslääkärin suorittama toimenpide. Hampaiden korjaukseen käytetään monenlaisia tekniikoita ja paikkamateriaaleja. Materiaalista, paikkausmenetelmästä ja täytteen paikasta riippumatta ongelmana ovat usein yhdistelmämuovikerrosten sisälle tai niiden pinnoille muodostuvat kuplat. Yhdistelmämuovista valmistetun restauraation on oltava homogeeninen, jotta täytteen saumasta tulee tiivis ja täyte kestää pitkään käytössä. Kuplavirheiden korjaaminen on työlästä, ja joskus osa täytteestä tai koko täyte on vaihdettava niiden takia. Virheiden määrä voi vaihdella yhdistelmämuovityypin (juokseva vai tahnamainen) sekä applikointitekniikan mukaan, mutta moni muukin tekijä vaikuttaa niiden syntyyn. 

Juoksevan yhdistelmämuovin injektiotekniikassa käytetään juoksevia yhdistelmämuoveja, joilla on luonnollisesti hyvä juoksevuus, mutta ne ovat myös alttiimpia käsittelyvirheille.  Ensinnäkin kuplia voi muodostua, jos itse materiaali ei ole homogeenistä. Kuplia voi tulla ruiskuun joko valmistuksen tai ruiskun käytön aikana. Laadukkaita tuotteita käyttämällä voidaan varmistaa, että toimitetut materiaalit ovat korkealaatuisia. Lisäksi hyvin suunniteltu ruiskun rakenne mahdollistaa oikeanlaisen käytön, jolloin kuplia syntyy vähemmän itse materiaalissa. 

CLEARFIL MAJESTY™ ES Flow -yhdistelmämuovi on suunniteltu niin, että kuplia syntyy mahdollisimman vähän annosteluvaiheessa. Ruiskun ja männän huolellinen suunnittelu vähentävät materiaalin vuotamisen ja takaisinvirtauksen mahdollisuutta annostelun aikana ja sen jälkeen.  

Ruiskun sisällä on turvaominaisuutena erityinen O-rengasrakenne, joka estää materiaalia valumasta ruiskusta paineen vapauttamisen jälkeen, ja varmistaa samalla sen, että retraktio on mahdollisimman vähäistä, eikä mäntä pääse vetäytymään liikaa. 

Kuplia voi tulla ruiskuun myös männän tietoisen vetämisen myötä. Jos hammaslääkärillä tai avustavilla henkilöillä on tapana vetää mäntä sisään yhdistelmämuovin annostelun jälkeen, ruiskuun voi päästä ilmaa. Ilma päätyy sitten luultavasti seuraavaan restauraatioon ilmahuokosen muodossa. 

Juoksevan yhdistelmämuovin injektiotekniikassa käytetään silikoni-indeksiä, johon materiaali ruiskutetaan hampaan valmistusta varten. Indeksin oltava on tiukasti kiinni hampaassa, eikä se saa liikkua injektoinnin aikana. Jos niin käy, ilmakuplia voi syntyä. Indeksin painaminen ja vapauttaminen aiheuttaa imua, joka vetää yhdistelmämuovia poispäin hampaasta ja indeksistä. Defektien välttämiseksi indeksiin on kohdistettava tasaista painetta aina materiaalin injektoinnista sen polymerointiin saakka. 

Silikoni-indekseistä on saatavilla useita muunnelmia, joilla voidaan vähentää sen liikkuvuutta ja siten hampaaseen kohdistuvaa hallitsematonta painetta. Yksi tällaisista malleista on vuorotteleva interlip-malli ("one yes one no"), joka tekee työskentelystä huomattavasti vakaampaa ja turvallisempaa. 

Injektioreiän koko voi myös vaikuttaa siihen, kuinka paljon restauraatioon pääsee ilmaa. Jos reikä on liian tiukka, indeksi voi liikkua paikaltaan applikointikärjen sisäänviennin tai käytön aikana. Ongelman välttämiseksi reiän tulisi olla tarpeeksi leveä, jotta kärjen sisäänvienti ja kärjen käsittely injektion aikana onnistuu vaivatta. Aukon ollessa leveämpi mahdollinen ilma pääsee myös poistumaan annostelun aikana. Tärkeintä on kuitenkin käyttää tasaista painetta materiaalin annostelun aikana ja välttää vetämästä ja työntämästä kärkeä uudelleen indeksiin, mikä voisi tehdä yhdistelmämuovikerroksesta epätasaisen. 

TOHTORI

MICHAL JACZEWSKI

Vuonna 2006 Wroclawin lääketieteellisestä yliopistosta valmistunut Michał Jaczewski toimii nykyään omassa yksityispraktiikassaan Puolan Legnican kaupungissa. Jaczewski on erikoistunut minimaalisesti invasiiviseen ja digitaaliseen hammashoitoon. Hän on myös okkluusiohoitojen biofunktionaalisen koulun perustaja. Sieltä käsin hän luennoi ja järjestää työpajoja, joissa keskitytään kokonaisvaltaisiin potilaiden hoitoihin. 

Technical Specialist for Chairside, Volkan Kacmaz, Introduces Himself

Volkan Kacmaz not only worked as a dentist in Turkey, but he also managed two clinics and earned a Master of Business Administration in Berlin. His diverse experiences seem to have led him to his current role as a Technical Specialist at Kuraray Noritake Dental Inc., headquartered near Frankfurt. Who is this friendly, smiley, and curious team member, and why did he specifically choose Kuraray?

While most dentists continue practicing dentistry throughout their careers, Volkan Kacmaz chose a different path. After graduating in 2011, he established his own dental clinic in Istanbul. A few years later, he served in the military for a year as a military dentist. Afterward, he founded two more franchise clinics, taking on the dual roles of manager and dentist. It was during this time that he realized dentistry wasn’t limited to clinical practice. “I’m eager to learn and have always been curious about how products work, the processes behind them, research and development, and the launch of new innovations,” he explains.

INNOVATION

In 2022, Kacmaz became the first dentist to enrol at the Berlin School of Economics and Law, where he learned about marketing, sales, negotiation, and regulations. Upon completing his Master of Business Administration, he made a deliberate decision to join Kuraray Noritake. “Kuraray Noritake's products are of very high quality, both labside and chairside. I already knew this from my experience as a dentist. The company has an excellent and trustworthy reputation among dental professionals,” he says.

Kacmaz also admires the innovative nature of the company. “Kuraray Noritake is responsible for some of the most significant innovations in dentistry. Just look at products like PANAVIA™ cement, the original MDP monomer, and multi-layered zirconia discs and blocks. It’s easy to see that Kuraray Noritake is a major force in the dental market. With their commitment to continuous improvement and innovation, you could call them the Apple of the dental world,” he adds.

Another aspect Kacmaz appreciates is Kuraray Noritake's product lineup. “The catalog isn't extensive, but it’s highly specialized. The company doesn’t produce just any product, but focuses on the ones it excels at, ensuring top-notch quality.” Lastly, Kacmaz loves the company culture. “It's a very respectful environment. I’ve had some bad experiences with respect in the past,” he says with a laugh, referring to his time in the military. “But at Kuraray Noritake, you can feel the respect for employees, which is very important to me. I’m very happy to be part of the Kuraray Noritake family.”

COURAGE

When comparing dentistry in Turkey to Western Europe, Kacmaz doesn’t see significant differences. “The brands, quality, and approaches are all the same.” However, he has noticed one small distinction: German dentists aren’t as enthusiastic about digital dentistry as their Turkish counterparts.

Kacmaz draws on all his previous experiences and knowledge in his role as part of the scientific marketing team. His responsibilities include finding scientific support for marketing initiatives. He collaborates with lecturers and dentists to manage research studies using Kuraray Noritake products, works to update measurements in response to market dynamics, and evaluates new products.

His goal? “To become an authority in the dental world,” he says with a smile. It may sound like an ambitious goal, but Kacmaz has learned to dream big. “The biggest decision of my life was leaving my comfort zone and moving to a country where I didn’t speak the language. But I believe it’s a courage you have to show. If you don’t, your dreams and plans will fade, and you’ll miss out on everything.”

LEARNING NEW THINGS

Moving to Germany, which Kacmaz describes as "the epicentre of the dental market," hasn’t always been easy. Coming from a Mediterranean culture, he was used to a more communal and lively environment. In Germany, he noticed that shops close early, and people value their privacy. Another challenge has been the language. While he prefers English, he says, “ein bisschen Deutsch, nicht so gut.”  Fortunately, Kuraray Noritake provides him with German lessons, and he has the best teacher at home—his three-year-old daughter, who learns the language faster than he does and sometimes corrects him.

Despite the challenges, all the adapting and hard work have been worth it. “I’ve realized that there are no limits to learning. Whether you’re in your 40s, 50s, or even 60s, there’s always something new to discover. You just have to be open to it.”

CONTACT

Volkan Kacmaz can be reached at +49 69 305 35134 or via [email protected].

ABOUT KURARAY NORITAKE DENTAL INC.

Kuraray was founded in 1926 in Kurashiki, Japan. Today, it is a leading global manufacturer of medical products, materials, textiles, chemicals, resins, and more. In 2012, Kuraray Medical and Noritake Dental Supply merged to form Kuraray Noritake Dental Inc. The company continues to deliver reliable dental bonding agents, ceramics, and other products to over 90 countries worldwide. Well-known products include the KATANA™ Zirconia range, CLEARFIL™ Universal Bond Quick, and PANAVIA™ resin cements.

Article by Dr. Michał Jaczewski

Resin composites are wonderful restorative materials: They allow for minimally invasive, defect oriented tooth preparation, may be modelled as desired, and can be modified and repaired whenever necessary. To achieve all of this, however, a strong and long-lasting bond is an absolute requirement. The bond needs to be established either between enamel and dentin on one side and the resin composite on the other, or between the existing and the newly applied composite material.

UNIVERSAL ADHESIVE

Committed to keeping clinical procedures as simple as possible, I use an 8th-generation bonding agent – CLEARFIL™ Universal Bond Quick (Kuraray Noritake Dental Inc.) in my dental office. Containing Rapid Bond Technology, it allows for a particularly easy and straightforward use without the need for extensive rubbing or long waiting times. At the same time, it bonds well to various substrates including enamel, dentin and resin composite as it contains the original MDP monomer.

Its composition and resulting versatility make CLEARFIL™ Universal Bond Quick the first choice for many indications including non- to minimally-invasive repair procedures. As it works extraordinarily well in situations where we want to bond to dentin, enamel or old composite (Fig.1), it is usually not necessary to remove the whole existing restoration that needs to be repaired or modified. Instead, preparation may be limited to the composite part, so that no additional tooth structure needs to be removed.

Fig. 1. CLEARFIL™ Universal Bond Quick establishes a strong bond to dentin, enamel or old composite.

CLINICAL PROTOCOL

Depending on the condition of the existing restoration surface, the repair protocol may be slightly different. The basic steps are as follows:

PROTOCOL 1: OXYGEN INHIBITION LAYER STILL ON THE SURFACE

- No surface treatment required, rinse with water in case of contamination with blood or saliva, followed by air-drying and (optionally) adhesive application

- Apply new layer of composite immediately

PROTOCOL 2: OXYGEN INHIBITION LAYER ALREADY REMOVED FROM THE COMPOSITE SURFACE

- Remove the composite around the defect and create a bevel at the cavity margin with rotating instruments

- Sandblast the surface with aluminium oxide particles

- Fresh composite surface: Clean the surface with KATANA™ Cleaner (Kuraray Noritake Dental Inc.) or etch with phosphoric acid etchant

- Composite surface older than two weeks: Etch with phosphoric acid etchant

- Apply the universal adhesive (which contains silane)

- Apply a new layer of composite

CLINICAL RECOMMENDATIONS

1. STAY IN THE COMPOSITE DURING PREPARATION

When an old composite restoration needs to be replaced – e.g. because the existing restoration shows discolouration or the patient asks for a brighter shade – it is possible to remove only a part of the composite and leave the rest in place to save the underlying healthy tooth structure. Accurate control over the amount of material removed and the amount of material left in place is offered by the use of UV light. Under UV light, the composite is perfectly visible (Fig. 2). Hence, a highly conservative structure removal is supported (Fig. 3).

Fig. 2. Controlling structure removal with UV light, which nicely reveals the old composite.

Fig. 3. Tooth preparation with rotating instruments.

2. INCREASE ADHESION BY SANDBLASTING

Creating a clean, micro-retentive composite surface ideal for bonding: This is the aim of sandblasting the affected composite area with aluminium oxide particles (Fig. 4). The particle size I prefer is 27 μm. Residual particles, may be removed with 37% orthophosphoric acid, which needs to be rinsed off thoroughly before air-drying the surface (Figs. 5a and 5b).

Fig. 4. Air-abrasion with 27 μm aluminium oxide particles.

Fig. 5a. Phosphoric acid etching. Adjacent teeth are protected with PTFE tape.

Fig. 5b. Thorough rinsing to remove the etchant from the surface.

3. USE A UNIVERSAL ADHESIVE THAT CONTAINS SILANE

When bonding to old composite, silanisation of the surface is recommended to increase the bond strength. On dentin, a separate silane shows no positive effect. Hence, it is recommended to apply a separate silane to the composite surface only, a challenging task in situations with a surface consisting of tooth structure and composite. As CLEARFIL™ Universal Bond Quick contains silane, the separate silane application step may be skipped, which clearly simplifies the procedure (Figs. 6a and 6b).

Fig. 6a. Application of CLEARFIL™ Universal Bond Quick to the prepared surface.

Fig. 6b. Solvent evaporation with a gentle stream of air.

4. IF IN DOUBT, USE A UNIVERSAL ADHESIVE DURING REPAIR PROCEDURES

Whenever detected during restoration, defects in the composite layer or air bubbles can be repaired or eliminated right away. As long as the oxygen inhibition layer is still present, another layer of composite may be applied immediately without any prior steps. However, if the surface has been contaminated by saliva or blood (Figs. 7a and 7b) or it is unclear whether we are bonding to dentin, enamel or composite, CLEARFIL™ Universal Bond Quick may be applied (Fig. 8). On top, a new layer of composite is placed to restore the defect (Fig. 9).

Fig. 7a. Composite surface with a defect near the margin with blood contaminating the affected area.

Fig. 7b. Composite surface with a defect near the margin after thorough rinsing and drying.

Fig. 8. Application of the universal adhesive.

Fig. 9. Application of composite material to restore the defect.

5. IF AVAILABLE, PLACE A SILICONE INDEX TO SIMPLIFY ANATOMICAL SHAPING

If the defect is small, it is possible to apply the flowable composite directly and remove the excesses (Fig. 10). The obtaining of a natural shape and smooth transition between old and new composite, however, is simplified by the use of a silicone index or matrix (Fig. 11), which might still be present from the original restoration procedure. A possible outcome of this type of repair is shown in Figure 12; both images were taken prior to finishing and polishing.

Fig. 10. Flowable composite spreading and excess removal.

Fig. 11. Silicone index placed over the teeth including the tooth with the defect.

Fig. 12. Outcome of the flowable injection procedure.

CONCLUSION

Elimination of bubbles or defects in a freshly created restoration, changes in the colour of an existing filling or a shape correction due to wear processes: Modifying composite restorations can be easy – provided that appropriate materials and techniques are used. One of the key elements on the path to success is the selection of a suitable adhesive system, preferably a universal single-bottle adhesive like CLEARFIL™ Universal Bond Quick, which allows for streamlined procedures and supports excellent outcomes. By respecting the provided tips, it is possible to create the desired outcomes in a minimally invasive, straightforward way, laying the foundation for long-lasting aesthetics and function.

Dentist:

MICHAŁ 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.

Leaving work at work, unplugging your mind from the dental office is not rocket science - provided that high-quality dental materials are used. Ideally, they are well-adapted to operator, case, and patient-specific needs. When it comes to restoring cavities with composite, Kuraray Noritake Dental Inc. has got the right products for any dental professional.

The CLEARFIL MAJESTY ES family of dental composites is composed of different product lines designed to meet specific needs. Altogether, the line-up offers a solution for every technique and handling preference, clinical situation and patient requirement.

UNIVERSAL SOLUTION FOR UTMOST SIMPLICITY

When utmost simplicity is desired, a highly innovative universal solution such as CLEARFIL MAJESTY ES-2 Universal is an excellent choice. This paste-type composite system includes only four shades: Universal, Universal Light, Universal Dark, and Universal White.

The Universal shade has the highest translucency and is, therefore, most suitable in cases where several cavity walls are still present, such as in Class I or II cavities and the cervical area. In cavities where light easily passes through, the lower-translucency variants Universal Light (for teeth with shades up to A3) and Universal Dark (for teeth darker than A3) are the best options. Universal White is the go-to solution for young patients and whitened teeth. Consequently, there is usually no need for a shade guide, and the optical properties allow application without an opaquer or blocker in most of cases. Both features greatly simplify the clinical procedure.

CLASSIC AND PREMIUM OPTIONS FOR SINGLE- AND DUAL-SHADE LAYERING

Clinicians who prefer classical single-shade layering according to a shade guide and a greater number of shades available may prefer CLEARFIL MAJESTY ES-2 Classic. With a line-up of 18 shades, it supports straightforward procedures and leads to aesthetic results.

Whenever the aesthetic needs are very high, such as in the context of restoring a large cavity in the aesthetic anterior region, CLEARFIL MAJESTY ES-2 Premium may be the best option. Designed for simplified multi-shade layering, it comes with fixed shade combinations of dentin and enamel opacity, that greatly support predictable outcomes.

MECHANICAL PROPERTIES

All the CLEARFIL MAJESTY ES paste-type composite systems offer a well-balanced viscosity and excellent mechanical properties, including

• a high flexural strength of 118 MPa
• a filler load of 78 wt%
• a compressive strength of 347 MPa
• a low volumetric shrinkage of 1.9 %
• a curing depth of 2.0 mm and
• a long working time under ambient light of 4.5 minutes
  
  

VERSATILITY POWERHOUSE IN THREE VISCOSITIES>

A flowable composite completes the portfolio. As the ideal level of viscosity depends on individual preferences and on the specific indication, CLEARFIL MAJESTY ES Flow comes in three different flowabilities: high, low and super low.

They have:

• a high flexural strength of 145, 151 and 152 MPa, respectively
• a filler load of 71, 75 and 78 wt%, respectively
• a compressive strength of 358, 373 and 374 MPa, respectively and
• a working time under ambient light of 100 seconds.

In addition, they are well-received for their easy application, fast polishing and high polish retention. All these features make the product a true versatility powerhouse. Moreover, it is offered in an innovative syringe designed for bubble-free application of the desired amount of composite and easy modelling.

THE IDEAL PORTFOLIO FOR PEACE OF MIND

The CLEARFIL MAJESTY ES portfolio offers highly suitable products for many clinical situations, demands and treatment techniques. As they support predictable outcomes and long-lasting success, using them gives dental practitioners the peace of mind needed to leave work at work and truly enjoy their free time—in the evening at home, on weekends or on holiday.

For more information about Kuraray Noritake Dental Inc.’s composite solutions visit the website.

Article by Dr. Michał Jaczewski

When working with composite, one of the most important aspects is to understand the mechanisms of adhesion. Choosing the right composite is one thing, but choosing a suitable bonding system and using it correctly is an equally important aspect affecting the long-term performance of a direct restoration.

There are many bonding products on the market - two-bottle (primer and bond) but also single-bottle systems. For anyone trying to select an ideal adhesive for a specific clinical case, the sheer number of available products can be challenging. The temptation to use them all, in slightly different ways, has the potential to create errors. In my dental practice, I am committed to simplifying procedures.

This is why I started looking for a bonding system that would offer a sense of security in terms of adhesion, but also ease of use in different clinical situations. I have opted for the 8^th-generation bonding agent with the desired features - CLEARFIL™ Universal Bond Quick (Kuraray Noritake Dental Inc.). The single-bottle universal adhesive is ideal for a broad variety of bonding procedures carried out in the dental office.

IMPRESSIVE FEATURES

CLEARFIL™ Universal Bond Quick can be used in the total-etch as well as the selective enamel etching technique in combination with an etching gel such as K-ETCHANT Syringe (Kuraray Noritake Dental Inc.). It is also a self-etching adhesive. Used in combination with the dual-cure build-up material CLEARFIL™ DC CORE PLUS or the dual-cure universal resin cement PANAVIA™ SA Cement Universal (both Kuraray Noritake Dental Inc.), it is also an ideal choice for cementation in the root canal and for cementing inlays or crowns made of a variety of different restorative materials – from metal to zirconia or lithium disilicate. Efficient clinical procedures are supported by the incorporated Rapid Bond Technology, which eliminates the need for extensive rubbing or waiting for the adhesive to penetrate the substrate and the solvent to evaporate. Among the key components of this technology are hydrophilic amide monomers, which allow the adhesive solution to penetrate moist dentin extraordinarily quickly, while also having a high curing ability. In addition, the original MDP monomer is included in the formulation. Together with the amide monomers, it provides for a high bond strength to enamel and dentin – achievable in a simple procedure of application, air-drying and light-curing.

The described properties turn CLEARFIL™ Universal Bond Quick into one of the most versatile and easy-to-use adhesive bonding solutions in the dental office. Operator sensitivity is low, as is its technique sensitivity, since the three-step procedure is always the same. The following case examples illustrate its use in the context of different repair procedures.

REPAIR OF COMPOSITE RESTORATIONS

One of the major benefits of using composite as a restorative material lies in the fact that it may be modified and repaired at any time. Regardless of whether an air bubble is detected on the surface, the shade needs to be adjusted, a fracture occurs or materials need to be added as a result of wear, modification or repair is easily accomplished without needing to sacrifice additional amounts of healthy tooth structure. Whenever a silicone index has been produced for the initial treatment and is still available, and the user knows which composite has been utilized for the original restoration, the Flowable Injection Technique may be selected as a particularly easy and efficient way of repairing a restoration. However the recommended protocol is slightly different depending on the state of the restoration surface.

CASE EXAMPLE 1: IMMEDIATE REPAIR PROCEDURE

When a restoration has been damaged or an air bubble has appeared during injection of a flowable composite, the procedure is slightly different. In this case, the oxygen inhibition layer is usually still present on the surface of the restoration. Therefore, it is possible to simply apply an additional portion of composite (Figs. 1a to 1d). Even after contamination of the composite surface with water, saliva or blood, this measure is possible. The surface merely needs to be rinsed thoroughly and dried before applying the new portion of composite. For maximum safety, a universal adhesive may be used as well.

Fig. 1a. Repair procedure applicable for defect within a composite restoration whenever the oxygen inhibition layer has not yet been removed: Air bubble detected in the interproximal region.

Fig. 1b. Application of a new portion of composite after rinsing and drying. The adjacent surface is protected with PTFE tape.

Fig. 1c. Repositioned silicone index used to give the restoration the originally planned shape.

Fig. 1d. Final restoration.

CASE EXAMPLE 2: REPAIR PROCEDURE AFTER POLISHING

If a similar defect is detected during finishing and polishing, i.e. when the oxygen inhibition layer has already been removed (Fig. 2), a roughening of the surface is strictly necessary. With a bevelled preparation of the area with the air bubble, optimal conditions are created for another layer of composite that blends in well with the surrounding material (Fig. 3). After bevelling, the surface needs to be sandblasted and cleaned either with KATANA™ Cleaner (Kuraray Noritake Dental Inc.) (Fig. 4a) or with 37 % orthophosphoric acid (Fig. 4b). After thorough rinsing and drying, an additional portion of composite may be applied to the surface (Figs. 5a to 5c). As the defect is small, the composite may be applied instead of injected and the silicone index repositioned afterwards.

Fig. 2. Void on the surface, detected during finishing.

Fig. 3.  Removed void and bevelled area around the defect.

Fig. 4a. Option 1: Cleaning of the surface with KATANA™ Cleaner.

Fig. 4b. Option 2: Etching with K-ETCHANT Syringe.

Fig. 5a. Application of composite (CLEARFIL MAJESTY™ ES Flow Low).

Fig. 5b. Repositioning of the original silicone index to obtain the desired shape.

Fig. 5c. Final restoration with a nice blend-in of the different layers of composite.

CASE EXAMPLE 3: REPAIR PROCEDURE AFTER TWO OR MORE WEEKS

For damaged restorations which have been in place for more than two weeks, an ideal composite-composite interface needs to be created by bevelling and roughening of the surface. A perfect example is presented in Figure 6. The most important step influencing the success of the procedure is proper preparation of the composite surface. To lay the foundation for a strong bond between the new and the old composite as well as for aesthetic outcomes, a bevel needs to be created (Figs 7a and 7b) to facilitate a smooth transition between the two layers. Once the bevel is completed, the surface should be sandblasted with alumina particles sized 27 μm (Fig. 8). The following recommended steps are etching of the composite with 37 % orthophosphoric acid (Fig. 9) and finally application of CLEARFIL™ Universal Bond Quick (Fig. 10). As the universal adhesive contains a silane coupling agent, separate silane application is not necessary. Instead, the new layer of composite may be applied immediately e.g. using the flowable injection technique with an existing matrix (Fig. 11).

Fig. 6. Fractured anterior composite restoration benefitting hugely from repair – the remaining composite is in a great state regarding colour and shape.

Fig. 7a.  Bevelling with dedicated instruments.

Fig. 7b.  Ideal bevel created to provide for a strong bond and great optical blend-in.

Fig. 8. Sandblasting of the surface with alumina particles.

Fig. 9.  Phosphoric acid etching.

Fig. 10. Application of the universal adhesive.

Fig. 11. Composite applied using the flowable injection technique.

Fig. 12. Treatment outcome.

CONCLUSION

The three described repair protocols are straightforward and work well – provided that a strong bond is established at the composite-composite interface. The way it is established may be slightly different depending on whether the oxygen inhibition layer is still present or has already been removed. Using a universal adhesive like CLEARFIL™ Universal Bond Quick, the procedure is simplified owing to elimination of steps such as the separate application of silane.

Dentist:

MICHAŁ 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.

DELICATE BALANCE BETWEEN COSTS AND AESTHETICS IN DENTAL LAB

When you are a lab owner striving to achieve high-end results using modern digital techniques, the initial investment in CAD/CAM technology is significant, followed by ongoing costs for expendable items such as milling tools and blanks. That cost can be reduced by selecting universal, high-quality materials.

Undoubtedly, zirconia stands out as one of the most popular materials on the market. From an inventory perspective, however, lab owners often find themselves purchasing multiple discs of the same shade and thickness. The reason is that they need to meet all requirements for strength and aesthetics in different settings – enabling them to cover all kinds of restorations and deliver excellent patient outcomes.

UNIVERSAL SOLUTION FOR DENTAL LABS

At Kuraray Noritake Dental Inc., we take pride in not only developing the first-ever multilayer zirconia, KATANA™ Zirconia ML, but also in our commitment to delivering the highest quality materials that we can.

KATANA™ Zirconia YML, our latest addition to the KATANA™ Zirconia line-up, exemplifies this dedication and offers universal applicability. The universal feature is based on the fact that KATANA™ Zirconia YML disc not only offers colour gradation, but also impressive flexural strength and translucency gradation, with maximum values of up to 1,100 MPa and 49 % translucency, respectively.

INHOUSE PRODUCTION - THE PATH TO HIGH QUALITY ZIRCONIA DISC

Like all our zirconia offerings, KATANA™ Zirconia YML begins its journey to the dental lab in our Japanese facility where raw zirconia powder undergoes special treatment process before the addition of essential components.

Once the material has undergone this thorough initial stage, it progresses to the pressing and pre-sintering phase to form the disc. Every detail is carefully calculated, managed and controlled. This phase of the process takes several days, underscoring our goal to achieve the most aesthetic product.

HIGH-SPEED SINTERING PROGRAM: 54 MINUTES

The unique powder formulation and refinement process, as well as the pressing and pre-sintering technique, is the key to allow our customers to realize restorations of up to three-unit bridges without any compromise in terms of aesthetics or mechanical properties using the 54-minute high-speed sintering* process.

This high quality, lengthy production process results in an exceptionally dense material, which once sintered, goes on to deliver a high strength, high aesthetic final restoration.

HIGH PRECISION SHRINKAGE AND STABLE CTE VALUES FOR EXCEPTIONAL FIT

Outstanding deformation stability during the sintering procedure, contributes to the stability during the final sintering process in the dental laboratory, providing for an exceptional fit of large-span bridges and other restorations.

MULTI-LAYERED STRUCTURE AND EASE OF POSITIONING OF RESTORATIONS IN THE BLANK

To enhance aesthetic qualities, all KATANA™ Zirconia YML discs are designed using ratios rather than fixed measurements of different layers in the multi-layered structure. This means that regardless of the disc's thickness, there is always a consistent ratio of 35 % of raw material that constitutes the translucent enamel zone. Hence, discs with an increased height, which are typically used for the production of larger restorations, will always offer sufficient space in the enamel zone, while smaller discs are optimized for smaller restorations.

ONE DISC. ALL INDICATIONS.

These qualities empower dental lab owners to deliver a wide range of restorations. The material is suitable for single crowns to full-arch structures, for full-contour designs to conventional frameworks, using a single material without compromising on aesthetics: KATANA™ Zirconia YML. For finishing, we offer a well-aligned portfolio of solutions designed for internal and external staining, micro-layering and full layering.

EXPLORE KATANA™ Zirconia YML: WEALTH OF RESOURCES, CLINICAL CASES AND FAQS

Visit our website to discover more about KATANA™ Zirconia YML. You will find useful materials such as brochure, technical guide, in-depth technical information.

Would you like to see the material in action – browse the blog section of our website that offers a variety of clinical cases and articles by world-renowned experts showcasing and proving the versatility and aesthetics of KATANA™ Zirconia YML.

*The material is removed from the furnace at 800°C. A furnace with a configurable KATANA™ Zirconia YML firing program is required.

FLOWABLE INJECTION AND STAMP TECHNIQUE: RESTORING TEETH IN THE POSTERIOR REGION

Restoring the occlusal surface of posterior teeth while preserving the natural morphology and re-establishing correct occlusal contacts has always been challenging for dental practitioners. Free-hand layering requires knowledge of tooth anatomy, composite handling skills and experience. When the occlusal surface of a tooth is damaged at the start of treatment (as is usually the case in teeth with large MOD cavities) or an increase of the vertical dimension of occlusion is planned (e.g. in severely worn teeth), the use of the flowable injection technique may be a suitable alternative. It truly speeds up and facilitates the process of building up the restoration to a natural shape, but requires thorough planning and preparation. In cases with an intact occlusal surface, the stamp technique might be the first choice.

FLOWABLE INJECTION TECHNIQUE: GENERAL CONSIDERATIONS

It is up to the user how exactly the restorations, to be built up by flowable injection, are planned and how the plan is implemented: One can either opt for a conventional wax-up or make use of digital tools in the planning phase. Dedicated design software offers the benefit of facilitating the creation of a natural shape and morphology of the desired restoration and allows for the establishing of an ideal occlusal relationship. Once the wax-up is ready, it needs to be transferred into the patient’s mouth. This is accomplished via a printed or classical model with wax-up, which forms the basis for the production of a matrix or silicon index. This index is then used intraorally for the injection of the flowable composite. To enable proper light curing through the index, the index material should be as transparent as possible.

AREA-SPECIFIC CONSIDERATIONS

In the posterior area, an index made of two different materials – a soft inner silicon structure and a hard outer shell – may be advisable. Due to its higher dimensional stability compared to a soft silicon index, it is possible to put pressure on it for proper adaptation to the isolated teeth and soft tissue without the risk of altering the shape of the tooth. Figure 1 shows such an index on and next to a printed model. It consists of a hard shell made of acrylic and a soft inner structure made of a transparent silicone material (e.g. EXACLEAR™, GC). For production, a high-capacity hydraulic pressure curing unit designed for use with self-curing resins (Aquapres™, Lang Dental) has proven its worth: It ensures a highly accurate reproduction of the (digital) wax-up.

Fig. 1. Printed model and silicone index.

Reconstruction of posterior teeth with the flowable injection technique requires prior removal of all carious lesions and reconstruction of the proximal surfaces to restore the contact points. Hence, the injected composite serves the exclusive purpose of restoring the occlusal surface. When several teeth are treated, a two-step procedure with an alternating technique is recommended to provide for proper separation of the teeth. Blocking the proximal surfaces below the contact point with PTFE tape will reduce the amount of excess material in these areas and make it easier to clean and prepare the proximal surfaces after flowable injection. Proximal and deeper occlusal lesions should be restored with the aid of a matrix, wedge and ring.

CLINICAL PROTOCOL

A possible clinical protocol is illustrated in Figures 2 to 5: After caries excavation and tooth preparation, sectional matrices, wedges and rings were placed to allow for simultaneous treatment of the mesial and occlusal cavities. Following etching and application of the universal adhesive CLEARFIL™ Universal Bond Quick (Kuraray Noritake Dental Inc.), the cavities were restored with CLEARFIL MAJESTY™ ES Flow Super Low in the shade A1 and CLEARFIL MAJESTY™ ES-2 Universal in the shade U. The distal cavity of the first molar was filled in the last step of the free-hand modeling procedure. In order to restore the occlusal surfaces in their original vertical dimension, every second tooth was isolated with rubber dam and the exposed molar etched (total-etch technique with K-ETCHANT Syringe, Kuraray Noritake Dental Inc.). the alternating index was positioned with some pressure and the flowable composite (CLEARFIL MAJESTY™ ES Flow Super Low) injected. Once light curing was completed, it was possible to remove the index, chip off the excess and finish and polish the restoration before repeating the procedure for the adjacent molar.

Fig. 2. Restoration of two molars: Teeth preparation and caries excavation.

Fig. 3. Restoration of two molars: Filling of the proximal and occlusal cavities.

Fig. 4.  Restoration of two molars: Re-establishing the occlusion with the aid of the flowable injection technique.

Fig. 5. Alternating approach: Restoration of the second molar by injecting flowable composite.

DISCUSSION

The use of the flowable injection technique allows for rapid restoration of teeth and the establishment of precise occlusal contacts. This reduces the time spend on occlusal surface modelling and minimizes the risk for prolonged treatment due to a repeated need for occlusal adjustments. In addition to saving time, it is possible with this technique to restore a greater number of teeth in a single appointment. The aesthetics of this type of restoration may be somewhat limited: A skilled practitioner is able to achieve better aesthetic results on the occlusal surface. However, with a detailed wax-up and high-quality model great outcomes can be obtained. The surface quality of printed models can be increased by adjusting the printing parameters including the layer height (Fig. 6). The use of a hydraulic pressure curing unit for silicone index production further increases the quality of the occlusal surface.

When planned and implemented correctly, the established occlusal surface and contacts reflect the natural anatomy without the need for adjustments (Fig. 7). Especially when restoring an entire quadrant, it is possible to increase the efficiency by opting for the flowable injection technique. Doing so reduces the number of appointments and the chair time decisively (Fig. 8).

STAMP TECHNIQUE: CONSIDERATIONS

If the occlusal surface of the tooth is intact, a wax-up may not be necessary. In this case, the better strategy is to duplicate what is still available before initiating treatment. A flowable composite or liquid rubber dam can be used for this purpose. It is important to coat the tooth surface with glycerin gel before applying the material. This will facilitate separation of the stamp from the tooth. It is always advisable to create a stamp that covers not only the details that need to be recorded and duplicated, but is extended over the cusps. This offers better stability in the restoration phase.

CLINICAL PROTOCOL

Figures 9 to 11 illustrate a possible clinical procedure. In this case, a molar with an occlusal carious lesion needed to be restored. The tooth surface was cleaned and a thin layer of glycerin gel applied, followed by a thick layer of liquid rubber dam, which covered the entire occlusal surface. Then, a micro applicator was immersed into the material and the stamp cured. After preparation, etching and application of the bonding system, the cavity was restored with flowable composite (CLEARFIL MAJESTY™ ES Flow Super Low in the shade A2). When the cavity is larger and depending on personal preferences, a paste-type composite (CLEARFIL MAJESTY™ ES-2 Universal) may also be used. Prior to light curing of the composite, the occlusal surface was covered with PTFE tape and the stamp pressed onto it. After firm pressing, the tape and excess material were removed and the restoration polymerized. This restoration faithfully reproduces the occlusal surface and did not require any occlusal adjustments.

Fig. 6. Stamp production with liquid rubber dam.

Fig. 7. The stamp.

Fig. 8. Restoration procedure: From preparation to bonding.

Fig. 9. Restoration procedure: Filling with flowable composite.

Fig. 10. Restoration procedure: Duplication the original occlusal surface with the stamp.

Fig. 11. Tooth before and after treatment using the stamp technique.

CONCLUSION

Techniques that add simplicity and efficiency to clinical procedures are always welcome in the busy practice environment. Depending on the information available at the start of treatment and the number of teeth to be restored, the flowable injection or the stamp technique may be an ideal choice. They are easily implemented and speed up the clinical procedure, but most importantly support predictable outcomes. This saves time in the finishing phase and minimized the risk of repeated adjustments, hence protecting everyone involved from additional appointments and frustration. Especially for practitioners with limited routine in free-hand modelling and for those with maximum patient comfort in mind, both techniques are worth being integrated in their clinical procedures.

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.

Tohtori Clarence Tam, HBSC, DDS, AAACD, FIADFE

Posliinilaminaatteja käytetään yleisesti esteettisissä hammashoidoissa etuhampaiden muodon, sävyn ja asennon korjaamiseen. Biomimeettisellä hampaiden korjauksella pyritään parantamaan hampaiden ulkonäön lisäksi myös niiden toiminnallisia ominaisuuksia. On tärkeää pitää mielessä, että etuhampaiden luontainen taivutusmurtolujuus on pitkälti riippuvainen ehjästä suulaki- ja fakiaalipintojen kiillekerroksesta. Jos hammas on vaurioitunut endodonttisen toimenpiteen, karieksen ja/tai trauman seurauksena, on pyrittävä säilyttämään jäljelle jäänyt hammasrakenne mahdollisimman hyvin, ja palauttamaan luonnonhampaan lähtötason ominaisuudet, tai parantamaan niitä.

TAUSTA

55-vuotias naispuolinen potilas, joka hakeutui vastaanotolle hampaiden valkaisua varten. ASA II -luokka. Hampaiden valkaisun ei arvioitu vaikuttavan olemassa olevan hampaan 1,2 posliinilaminaatin sävyyn. Laminaattikäsittely olisi uusittava toimenpiteen jälkeen, etenkin jos sävyarvojen muutokset olisivat merkittäviä. Potilaan yläetuhampaiden lähtötasosävyinä oli VITA* 1M1 ja 2M1 (50:50) ja alaetuhampaiden 1M1. Käytettyään karbamidiperoksidia (10 %) sisältävää valkaisulusikkaa öisin 3-4 viikon ajan potilas onnistui saavuttamaan valkaisutuloksen VITA* 0M3 sekä ylä- että ala hammaskaaressa. Valkaisun seurauksena hampaan 1,2 laminaatilla ja viereisellä hampaalla oli huomattava kirkkausero, minkä lisäksi kontralateraalisessa hampaassa 2,2 havaittiin kroman lisäystä fakiaalipintoihin vaikuttavan luokan III yhdistelmämuovipaikan vuoksi. Jälkimmäinen hammas ei myöskään vastannut kontralateraalihampaan mittoja, minkä vuoksi molempiin lateraaliseen kakkoshampaaseen päätettiin laittaa sidostetut litiumdisilikaattilaminaatit. Viereisessä kulmahampaassa (2,3) oli havaittavissa vähäistä tai kohtalaista kuspien kärkien kulumista, mutta potilas ei halunnut käsitellä asiaa ennen aiemmin mainittujen laminaattien asentamista. Esteettisen hammashoidon päätavoitteena oli tässä vaiheessa bilateraalisen harmonian saavuttaminen. Lähitulevaisuudessa hampaaseen 2,3 oli tarkoitus lisätä epäsuora täyte kuspien kärkien ja fakiaalipintojen normaalin muodon palauttamiseksi.

TOIMENPIDE

Lateraalisten kakkoshampaiden hammaskohtaiseen hoitoon (ensimmäinen hoidonaihe) ei tarvittu Digital Smile Design -protokollaa. Pieni vaihtelu hyväksytään tällaisessa hammastyypissä, sillä se tekee hymystä persoonallisemman ja ilmentää henkilön sukupuolta. Tavoitesävy valittiin ennen anestesiaa polarisoitujen ja polarisoitumattomien kuvien perusteella, jotka oli otettu retraktoria käyttämällä. Valokuvat valmisteltiin digitaalista sävyjen kalibrointia varten ottamalla vertailukuvia, joissa käytettiin 18 % neutraalia harmaavalkotasopainokorttia (kuva 1).

Kuva 1. Vertailukuva, jonka ottamiseen on käytetty 18 % neutraalia harmaakorttia.

Rungon perussävy oli VITA* 0M2 ja aihion sävy BL2. Potilaan anestesiaan käytettiin 1,5 ampullia 2-prosenttista lidokaiiniliuosta ja 1:100 000 adrenaliinia, ennen kuin suuhun asetettiin kofferdamkumi split dam -tekniikalla. Hampaan 1,2 laminaatti leikattiin ja poistettiin hampaasta 1,2. Hampaalle 2,2 tehtiin minimaalisesti invasiivinen laminaattipreparointi (kuva 2). Osa hampaan 1,2 vanhasta mesioinsisiaalibukkaalipalataalipuolisesta yhdistelmämuovipaikasta korvattiin. Ehjä osuus jätettiin paikoilleen. Vanhan yhdistelmämuovipaikan ja uuden täytteen sidostamiseen käytettiin sekä mikrohiukkasabraasiota että silaaniperustaista kiinnitysainetta (CLEARFIL™ CERAMIC PRIMER PLUS). Saumat viimeisteltiin, ja retraktiolankoja liotettiin aluminiinikloridiliuoksessa ennen niiden asettamista ientaskuihin. Preparoitujen tynkien sävyt kirjattiin muistiin. Lopullisten jäljennösten ottamiseen käytettiin metallialustaa ja kevyt- ja paksujuoksuista polyvinyylisiloksaania. Potilaalle asennettiin tilapäislaminaatit, ja mukaan annettiin ohjeet, joissa kehotettiin tarkistamaan sävy laboratoriossa raakapolttovaiheessa (bisque-poltto). Laboratorion valmistamat mallit ovat osoitus tapauksen minimaalisesti invasiivisesta luonteesta.

Kuva 2. Laminaattia varten preparoidut hampaat 1,2 ja 2,2

Tapauksen vastaanoton jälkeen potilas nukutettiin ja tilaspäislaminaatit poistettiin. Preparoidut hampaat revidoitiin, ja sidostettavat pinnat hiekkapuhallettiin, jossa käytettiin 27 mikronin hiukkaskoon alumiinioksidijauhetta 30-40 psi:n (0,2–0,29 Mpa) paineella. Laminaattien lopullisen tuloksen arviointiin käytettiin läpinäkyvää glyseriinipohjaista sovituspastaa (PANAVIA™ V5 Try-in Paste Clear, Kuraray Noritake Dental Inc.) Retraktiolangat asetettiin ientaskuihin ja restauraatioiden sisäpinnan (intaglio) käsittelyyn käytettiin 5-prosenttista fluorivetyhappoa, jonka annettiin vaikuttaa 20 sekuntia, minkä jälkeen hampaalle levitettiin 10-MDP-monomeeria sisältävää silaaniperustaista kiinnitysainetta (CLEARFIL™ CERAMIC PRIMER PLUS) (kuva 3). Hampaan pinta etsattiin 33-prosenttisella ortofosforihapolla, jonka annettiin vaikuttaa 20 sekuntia, minkä jälkeen aine huuhdeltiin pois. Hampaaseen levitettiin 10-DMP-monomeeria sisältävää esikäsittelyainetta (PANAVIA™ V5 Tooth Primer) (kuva 4), joka ilmakuivattiin valmistajan ohjeiden mukaisesti. Laminaattisementtiä (PANAVIA™ Veneer LC Paste Clear) (kuva 5) lisättiin, ja laminaatit asetettiin paikoilleen. Laminaatti pysyi hyvin paikoillaan ylimääräisen sementin jähmeyden ansiosta kaikkien sauman tarkistustoimenpiteiden aikana ennen 1 sekunnin pistekovetusta (kuva 6).

Kuva 3. CLEARFIL™ CERAMIC PRIMER PLUS -esikäsittelyainetta on lisätty laminaattien sisäpinnoille.

Kuva 4. PANAVIA™ V5 Tooth Primer -esikäsittelyainetta lisätään etsatuille hampaan pinnoille.

Kuva 5. PANAVIA™ Veneer LC Paste Clear -pastaa lisätään preparoitujen laminaattien sisäpinnoille.

Kuva 6. PANAVIA™ Veneer LC Paste heti laminaatin paikoilleen asettamisen jälkeen. Huomaa paksujuoksuisen sementin jähmeys, mikä helpottaa sen poistamista sekä nestemäisessä että geelimäisessä olomuodossa.

Kovetuksen jälkeen sementti oli geelimäistä, joten ylimääräinen sementti oli helppo poistaa, eikä puhdistusta juurikaan tarvittu (kuva 7). Saumat peitettiin läpinäkyvällä glyseriinigeelillä ennen lopullista kovetusta happi-inhibitiokerroksen poistamiseksi (kuva 8).

Kuva 7. Ylimääräisen sementin poisto 1 sekunnin pistekovetuksen jälkeen.

Kuva 8. Laminaattien palataali- ja fakiaalipintojen samanaikainen lopullinen kovetus.

Saumat viimeisteltiin, ja ne kiillotettiin korkeakiiltoisen lopputuloksen saamiseksi. Restauraatioiden purennan sopivuus varmistettiin. Postoperatiiviset kuvat todistavat, että saumat sulautuvat erinomaisesti hammasrakenteeseen (kuva 9).

Kuva 9. Laminaattien 1,2 ja 2,2 postoperatiivinen esteettinen integraatio.

Uutta hymyä arvioitiin polarisoiduilla kuvilla, jotka osoittavat, että restauraatiot sopivat uuteen hymyyn hyvin sekä esteettisiltä että toiminnallisilta ominaisuuksiltaan (kuva 10). Enää puuttuu vain hampaan 2,3 esteettinen augmentaatio, jotta hampaan ulkonäkö vastaisi kontralateraalista kulmahammasta.

VALMIS RESTAURAATIO

Kuva 10. Uudelleenarvioinnissa käytettävä polarisoitu kuva, joka näyttää lopullisen lopputuloksen.

Dentist:

CLARENCE TAM

References

1. Magne P, Douglas WH. Rationalization of esthetic restorative dentistry based on biomimetics. J Esthet Dent. 1999;11(1):5-15. doi: 10.1111/j.1708-8240.1999.tb00371.x. PMID: 10337285.
2. Magne P, Douglas WH. Porcelain veneers: dentin bonding optimization and biomimetic recovery of the crown. Int J Prosthodont. 1999 Mar-Apr;12(2):111-21. PMID: 10371912.
3. Pongprueksa P, Kuphasuk W, Senawongse P. The elastic moduli across various types of resin/dentin interfaces. Dent Mater. 2008 Aug;24(8):1102-6. doi: 10.1016/j.dental.2007.12.008. Epub 2008 Mar 4. PMID: 18304626.
4. Source: Kuraray Noritake Dental Inc. Samples (beam shape; 25 x 2 x 2 mm): The solvents of each material were removed by blowing mild air prior to the test.

Laadukkaiden proteettisten hoitojen merkitys

Hoidonlaatu on luultavasti tärkein potilastyytyväisyyteen vaikuttava tekijä. Potilaat haluavat kokea, että joka ikisellä käynnillä heidän hoitoonsa paneutuu osaava ja välittävä ammattilainen. Käyntien keston ja määrän tulisi kuitenkin olla mahdollisimman pieni. Proteettisten hoitojen kohdalla tämä tarkoittaa sitä, että protetiikan tulisi sopia täydellisesti hampaistoon jo ensikokeilulla. Sen on myös pysyttävä stabiilina käytössä, jotta lisäkäynneiltä vältytään, eikä uusia proteesiversioita tarvitsisi tehdä.

Mutta miten on mahdollista tuottaa kerta toisensa jälkeen laadukkaita, täydellisesti potilaan suuhun sopivia restauraatioita? Tiedetään, että tavalliset klinikoiden ja laboratorioiden tekemät valmistusvirheet sekä kommunikointiongelmat voivat heikentää epäsuorien täytteiden lopputulosta, mutta huonolaatuisen hammaszirkonian käytön vaikutus usein sivuutetaan.

Zirkoniarestauraatiot – nykyaikainen ja esteettinen hammashoidon ratkaisu

Yli 20 vuotta sitten zirkoniaa alettiin käyttämään hammasalalla metallin sijaan kruunujen ja siltojen valmistuksessa. Sekä zirkonia- että metallirestauraatioihin lisättiin yleensä posliinikerros, jolloin tuloksena oli joko metallokeraaminen tai kerrostettu zirkonia restauraatio. Tulevina vuosina useat johtavat hammaszirkonian valmistajat (kuten Kuraray Noritake Dental Inc.) paneutuivat uuden materiaalin kehitystyöhön. Kehitystyön tuloksena alkuperäisestä läpikuultamattomasta, vaaleasta runkomateriaalista kehkeytyi lopulta luja keraaminen materiaali, jonka erinomaiset optiset ja mekaaniset ominaisuudet mahdollistavat luonnollisten restauraatioiden valmistamisen. Monet hammasalan ammattilaiset eri puolilta maailmaa pitävät useilla läpikuultavuuksilla ja lujuuksilla saatavilla olevaa hammaszirkoniaa parhaana materiaalivalintana monentyyppisille potilaille ja eri indikaatioihin. Ohut posliinikerros riittää, tai sitä ei välttämättä tarvita lainkaan, mikä onkin yksi syy zirkoniarestauraatioiden suosioon. Lisäksi zirkoniarestauraatioiden maltillinen seinämän vähimmäispaksuus mahdollistaa hammasta säästävän preparoinnin, ja restauraatiot toimivat hyvin pitkällä aikavälillä. Näin on kuitenkin vain silloin, kun restauraatioihin käytetään korkealuokkaisia materiaaleja.

Eri laatuiset hammaszirkoniat

Zirkoniatuotteen laatu voi vaihdella esimerkiksi zirkonian ja alumiini- ja yttriumoksidin tai väriaineiden ja muiden raakamateriaalien puhtauden, tuotteen eksaktin kemiallisen koostumuksen, rakeiden koon, hiukkasjakauman ja monen muun eri tekijän mukaan. Lisäksi kukin aihion valmistusvaihe jauheen koostamisesta aihion prässäykseen ja esisintraukseen vaikuttaa lopputuloksen laatuun, eli zirkonian mekaanisiin ja optisiin ominaisuuksiin.

Yleisiä heikkolaatuisen zirkonian aiheuttamia ongelmia

Mahdolliset optiset ominaisuuksien ongelmat tulevat ilmi laboratorion tekemän viimeisen sintrauksen yhteydessä. Ne voivat liittyä esimerkiksi restauraation läpikuultavuuteen, yleiseen värisävyyn tai monikerroszirkonioiden tapauksessa kerrosten värisiirtymiin. Restauraation valmistusprosessi voidaan joutua aloittamaan alusta, ja restauraation sovituksen yhteydessä esille tullut laatuvirhe on omiaan heikentämään potilastyytyväisyyttä. Sama pätee myös esimerkiksi epätasaisesta materiaalista johtuviin istuvuuspulmiin. Huono bioyhteensopivuus, pinnanlaatu, reunojen stabiilius sekä taivutus- ja murtumislujuus ja voivat erityisesti heikentää huomattavasti lopputuloksen laatua. Tällaiset ongelmat pystytään tunnistamaan vain erittäin kalliiden testauslaitteiden avulla, joita hammaslaboratorioissa ei yleensä ole saatavilla. Tällaiset laatuvirheet tulevatkin siis usein esille vasta todellisten kliinisten ongelmien yhteydessä, joita voivat olla esimerkiksi ienten vetäytyminen, plakin lisääntyminen, suurempi kuluminen tai mahdollisesti kipua tai epämukavuutta aiheuttava paikan ennenaikainen epäonnistuminen.

Mahdollisten ongelmien ja niiden potilaalle aiheuttamien seurauksien yleiskatsaus

Hammaszirkonioiden sertifiointi ja standardisointi

Tämän vuoksi asiantuntijat ovatkin kehittäneet ISO-standardin (ISO 6872:2015), jossa kuvataan mitkä in-vitro-testit kunkin Euroopassa tai Yhdysvalloissa hammaszirkonioitaan markkinoivan yhtiön on suoritettava, jotta tuote saa FDA-hyväksynnän tai CE-merkinnän. Standardissa mainituilla testeillä mitataan taivutus- ja murtolujuutta, jotka ovat todennäköisesti kaksi suurinta materiaalista tehtyjen restauraatioiden pitkän aikavälin toimivuuteen vaikuttavaa tekijää. Kaikkien Euroopassa tai Yhdysvalloissa käytettyjen materiaalien on läpäistävä nämä testit.

Kuinka välttyä tekemästä heikkolaatuisista hammaszirkonioista valmistettuja restauraatioita

Luulisi siis, että näiden sertifioitujen hammaszirkonioiden käyttö olisi turvallista, eikä muita toimia materiaaleihin liittyvien riskien minimoimiseksi tarvitse tehdä. Hammaszirkonian kasvava suosio on kuitenkin herättänyt sellaisten yritysten huomion, jotka haluavat oman siivunsa tienesteistä näkemättä kuitenkaan vaivaa tuotteen laadun tai sertifikaatin vaatimusten täyttämisen eteen. Kaikilla sertifioimattomilla tuotteilla, joilta CE-merkintä puuttuu, on jotakin yhteistä: ne vaarantavat yrityksesi maineen ja potilaasi turvallisuuden.

Miten zirkoniatuotteiden laadusta voidaan sitten varmistua hammasklinikalta käsin? Yksinkertaisia ohjeistuksia tähän on onneksi olemassa: niitä noudattamalla voit välttyä asettamasta väärennetyistä tai heikkolaatuisista zirkonioista tehtyjä restauraatioita potilaasi suuhun.

Älä aseta väärennetyistä tai heikkolaatuisista hammaszirkonioista tehtyjä restauraatioita potilaan suuhun.

Kolme kultaista sääntöä, joilla voit varmistaa valmistamiesi zirkonirestauraatioiden ensiluokkaisuuden:

• Tilaa vain restauraatioita, jotka on valmistettu kotimaassasi, tai alueilla, joilla on käytössään vastaavat standardit. Esimerkiksi Kiinassa restauraatioiden valmistusprosessia koskevat standardit ovat löyhempiä, joten niillä ei ole CE-merkintääkään, eivätkä ne siten välttämättä täytä odotuksiasi.
• Keskustele (kotimaisen) laboratoriokumppanisi kanssa tämän käyttämästä zirkoniasta: varmista, että kumppanisi ostaa zirkonian johtavien valmistajien (kuten Kuraray Noritake Dental Inc:in) valtuutetuilta jakelijoilta tai muilta varmasti luotettavilta jälleenmyyjiltä.
• Vältä tekemästä hankintoja, jotka vaikuttavat liian hyviltä ollakseen totta: matalat hinnat voivat olla houkuttelevia, mutta lopullinen hoidon hinta voi nousta normaaliakin korkeammaksi, mikäli komplikaatioita ilmenee.

Sertifioitujen zirkoniarestauraatioiden pitkän aikavälin merkitys potilaalle

Voit vaikuttaa huomattavasti potilaiden pitkäaikaistyytyväisyyteen varmistamalla, että klinikallasi käytetään vain tiukimpien laatukriteerien mukaisia zirkonioita. Korkealaatuisten zirkoniarestauraatioiden alkukustannukset voivat olla heikkolaatuisten restauraatioiden kustannuksia suuremmat, mutta ne voivat silti tulla halvemmiksi, sillä ne kestävät pidempään eikä vaihtoja tarvitse tehdä. Tyytyväiset potilaat hakeutuvat todennäköisemmin uudelleen vastaanotollesi ja noudattavat huolellisemmin suun hygieniaa koskevia ohjeistuksia, mikä auttaa vahvistamaan sekä mainettasi että potilaspohjaasi.

Tee taustatutkimusta ja valitse sertifioitujen valmistajien zirkoniatuotteita

Voit mennä vielä astetta pidemmälle ja verrata useiden eri valmistajien sertifioituja zirkoniamateriaaleja keskenään eroavaisuuksien löytämiseksi. Kuraray Noritake Dental Inc. on esimerkiksi yksi niistä hyvin harvoista hammaszirkonian valmistajista, jotka huolehtivat itse koko valmistusprosessista raakamateriaalien valmistuksesta alkaen. Näin yhtiö voi valvoa tuotannon jokaista vaihetta, ja valmistaa ensiluokkaisia tuotteita materiaalivariantista riippumatta. Yhtiön KATANA™ Zirconia UTML (äärimmäisen läpikuultava, monikerroksinen), KATANA™ Zirconia STML (erittäin läpikuultava, monikerroksinen) ja erittäin läpikuultava HTML PLUS sekä YML (erityisen vahva, eri läpikuultavuusasteita) varmistavat, että tuotevalikoimasta löytyy oikea tuote käytännössä jokaista indikaatiota varten.

Presented by Kuraray Noritake Dental Inc.

Highly translucent multi-layered zirconia developed by a proprietary material and manufacturing method from Japan

CURRENT STATUS AND FUTURE PROSPECTS OF ZIRCONIA RESTORATIONS

In this issue, we asked Markus B. Blatz, Professor at the University of Pennsylvania, USA, Aki Yoshida (Gnathos Dental Studio) and Naoki Hayashi (Ultimate Styles Dental Laboratory), both dental technicians active in the USA and international instructors for Kuraray Noritake Dental Inc., to give their views on zirconia restorations and their outlook for the future.

WITH THE INTRODUCTION OF ZIRCONIA, THE MAINSTREAM OF PROSTHETIC TREATMENT HAS SHIFTED FROM METAL CERAMICS¹ TO ZIRCONIA CERAMICS². WHAT CHANGES HAVE OCCURRED WITH THE INTRODUCTION OF ZIRCONIA?

Blatz: My mentor for my first Ph.D. in dental materials was in the group that developed lithium disilicate and glass-infiltrated alumina. Therefore, I have seen the evolution of dental ceramic materials, including zirconia, which is the subject of this presentation, up close and personal.

Early zirconia was white, opaque, and not as esthetic as today. However, there is no doubt that zirconia ceramics were much more esthetic than metal ceramics. At the same time, however, we often heard the opinion that bilayer zirconia ceramic restorations were problematic, and this provoked much discussion. We conducted a large study in collaboration with a Boston laboratory to compare more than 1,000 posterior porcelain-fused-to-metal crowns and 1,100 posterior porcelain-fused-to-zirconia crowns and found no difference in chipping or fracture rates after about seven years. This proves that bilayer zirconia ceramics are safe when used with the proper veneering materials and the proper sintering and cooling protocols. The fact that zirconia became established as it is today is a major change for dentistry in general.

Yoshida: I also switched from metal ceramics to zirconia ceramics, and now I don't use metal anymore. It used to take a lot of time and effort to invest and cast metal, observe it with a microscope, and fit it. Considering the recent rise in metal prices, it has also become more cost-effective. In addition, I am allergic to metal and have a skin rash every time I have a prosthetic processed, so the shift to zirconia ceramics as the mainstream prosthetic is a welcome change. Of course, the use of zirconia has also improved esthetics. The translucency of zirconia is the greatest advantage that metal does not have.

Hayashi: Yes, that's right. The big advantage of zirconia is that if the abutment is not strongly discolored, it no longer needs to be treated with an opaquer. It was not easy to control the reflection of light from the operative tooth when fabricating metal ceramics. In addition to the esthetic advantage, the prosthetic space can be thinner than that of metal ceramics.

1. Metal ceramics: Prosthetic made of metal frame with porcelain.
2. Zirconia ceramics: Prosthetic made of zirconia frame with porcelain.

THE YEAR 2023 MARKED THE 10^TH ANNIVERSARY OF THE FIRST MULTI-LAYERED ZIRCONIA – KATANA™ ZIRCONIA ML. SINCE THEN, HOW DO YOU THINK HIGHLY TRANSLUCENT MULTI-LAYERED ZIRCONIA HAS REVOLUTIONIZED PROSTHETIC DEVICE MANUFACTURING?

Yoshida: I feel the ability to extend the zirconia frame to the occlusal surface and the incisal edge is the greatest advantage of using highly translucent multilayered zirconia. This allows us to provide crowns of both esthetics and strength, even for patients with para function. I have also made a zirconia Maryland bridge using highly translucent multi-layered zirconia, and it is doing very well. There are some cases where it is not possible to use zirconia, but still, it is wonderful to have a wider range of options.

Blatz: Many people still have the impression that zirconia cannot be bonded to tooth structure, but resin cement can be used to bond zirconia to tooth structure after proper pretreatment. Clinical studies of resin-bonded zirconia bridges have shown very high success after 10 or 15 years. Currently, resin bonding is recommended for very thin, highly translucent zirconia, rather than cementation. However, it should be added that this requires the dentist and technician to understand the proper bonding technique for zirconia.

In addition, Kuraray Noritake Dental's multi-layered zirconia has revolutionized monolithic zirconia without the need for veneering porcelain. However, this has also resulted in the need for dental technicians to shift to a different approach: instead of building up the restoration as with veneering ceramics, esthetic features are created on the outer surface in each case.

Maxillary 6 anterior monolithic crowns (Markus B. Blatz)

Fig. 1a and b: Initial examination.

Fig. 1c: Simulation of final prosthetic restoration.

Fig. 1d: Completed prosthetic on model (monolithic crown using KATANA™ Zirconia STML).

Fig. 1e and f: Final restoration (Dr. Julian Conejo and Sean Han, CDT).

Two cases of Maryland bridge and laminate veneers and a mandibular canine single crown implant superstructure (Aki Yoshida)

Fig. 2a and b: Case 1: A case of a congenital defect of a lateral incisor was restored with a Maryland bridge. Since the proximal and distal width of the defect was greater than the central incisor, a non-prep veneer was fabricated on the central incisor to balance the proportions. KATANA™ Zirconia STML was used for the Maryland bridge. Note the harmony between the zirconia frame extended to the incisal edge and the transparency of the laminate veneers made of Super Porcelain EX-3™ on the central incisors. This case demonstrates the characteristics of zirconia, which combines strength and esthetics.

Fig. 3a to c: Case 2: A case of a screw-retained crown restoration of an implant placed in a mandibular canine tooth. Extension of the zirconia frame from the entire lingual side to the incisal margin prevents fracture of the porcelain by the screw access hole edges and canine guides. KATANA™ Zirconia STML provides natural transparency even when zirconia is exposed at the incisal edge.

Maxillary 4 Anterior teeth implant bridge (Naoki Hayashi)

Fig. 4a to f: Implant bridge of maxillary four anterior teeth using implants placed in the maxillary bilaterallateral incisors as abutments and maxillary bilateral central incisorsaspontics. The lingual side is fully backed with zirconia and the labial side is minimally layered with CERABIEN™ ZR.

Hayashi: Indeed, the highly translucent multilayered zirconia has expanded the possibilities of monolithic crowns. For patients with high occlusal forces, monolithic crowns are suitable in terms of strength, and with the use of highly translucent multilayered zirconia, it is possible to achieve a certain level of esthetics with monolithic crowns. In fact, some patients are happy with it. However, at least in the current situation, we believe that if patients and dentists want high-end esthetics, then porcelain buildup is necessary, and monolithic crowns are only an option.

Blatz: The variety of options available is the advantage of zirconia. The dentist and the technician can work together to provide the best possible outcome for the patient.

Yoshida: In terms of options, Kuraray Noritake Dental's zirconia can be sintered in a short time (approximately 90 minutes) in addition to the normal sintering time (7 hours) using a zirconia raw material and manufacturing method developed by Kuraray Noritake Dental, which is an advantage in that it can be used for immediate restorations, remanufacturing and other unexpected situations.

FINALLY, DO YOU HAVE A MESSAGE FOR THE NEW GENERATION OF DENTISTS AND DENTAL TECHNICIANS?

Blatz: I encourage my students and colleagues to always do their best. This leads to good results, makes you happy, and makes you feel satisfied with your life. Some people only try to get rich, but just accumulating wealth is never happiness. The second is to keep an open mind. Nowadays, we are inundated with information through social media.

Some of it is very stimulating and wonderful, but there is also a lot of it that is wrong. On the other hand, there are those who believe that everything one leader says must be done. I would like to tell them, "Make sure you get your information from reliable sources, and then choose reliable information for yourself. Dentistry is changing, so let's keep an open mind. The most important thing is that the patient is ultimately satisfied with the results.

Hayashi: I would like the future generation to learn more about tooth morphology, occlusion, and fit. Color is the essence of the quality of the final prosthetic device, but we need to learn tooth morphology, occlusion, and fit before we learn color. We are all about creating a prosthetic device that will function in the patient's mouth for the long term, and that is our goal. There will be new technologies and materials in the future, but their essence will never change. I hope that you will always remember what is important in your clinical practice. This is why basic knowledge of anatomy and function is necessary.

Yoshida: New technologies and materials will continue to emerge. But human teeth will not change. The most important thing is to provide the best possible care to the patient. I hope that you will accumulate such experiences, and that when you reach the end of your life, you will be able to say that you are glad you chose this profession.

Thank you very much for the meaningful discussion today.

Source: QDT Vol.49/2024 April
The magazine may not be printed from the web and may not be forwarded
No reproduction or reprinting allowed

Dentists:

KATANA™ Zirconia YML offers an unmatched blend of aesthetics and mechanical properties, but also provides for cost and time efficiencies.

Recognised for its strength and density at point of manufacture, the material delivers incredible hardness in its green state. This offers the fully validated opportunity to make adjustments in morphology directly after milling.

These qualities, along with its strength and translucency once sintered, deliver the possibility to produce a wide range of high aesthetic indications. KATANA™ Zirconia YML has set a new benchmark in prosthetic dentistry.

It provides dental technicians with a material that is truly universal with no compromises required.

KATANA Zirconia YML in a Nutshell

KATANA Zirconia YML represents a pinnacle of zirconia technology. With its multi-layered structure, it offers a seamless gradation of colour, strength and translucency that mimics natural teeth, making it an ideal choice for the entire indication spectrum.

The material's unique composition allows for high-speed sintering (up to 3-unit bridges), which significantly reduces production time without sacrificing optical or mechanical properties.

Colour Gradation and Physical Properties

The colour gradation of KATANA Zirconia YML is designed to replicate the natural colour transition of human teeth, from the dentin core to the translucent enamel surface.

This combined with the material's impressive flexural strength of up to 1,100 MPa and translucency of up to 49%, enables the production of restorations that are virtually indistinguishable from natural dentition.

Applications and Advantages of KATANA Zirconia YML

KATANA™ Zirconia YML's versatility extends to a wide range of indications, including crowns, veneers, inlays, onlays, and bridges of all sizes. With its strong body and highly translucent enamel layer, it offers exactly the properties required for an unlimited indication range.

Positioning of restorations in KATANA™ Zirconia YML discs is extraordinarily easy. The reason is that the gap between the lowest flexural strength found in the enamel area and the highest flexural strength found in the lowest body layer is comparatively small. Moreover, the Body Layer 1 that is found adjacent to the enamel layer already offers a flexural strength that is higher than the 800 MPa requested for bridges with four or more units. Consequently, the material is classified as a Class 5 zirconia and users are on the safe side whenever they place their long-span restorations in the middle of the blank.

Positioning of long-span restorations in the middle of the disc.

Revolutionizing Sintering with High-Speed Capabilities

One of the groundbreaking aspects of KATANA Zirconia YML is its compatibility with high-speed sintering protocols. This capability allows dental laboratories to expedite the production process, delivering high-quality restorations in a fraction of the time traditionally required. Sintered during normal working hours at daytime, small restorations can be finished within hours, while the sintering load at night is reduced automatically. Great option not only for rush cases!

The high-speed sintering process does not compromise the material's optical or mechanical properties, maintaining its aesthetics and strength.

Recommended Finishing Techniques for Optimal Results

KATANA Zirconia YML is a beautiful and aesthetic material in its own. Therefore, when it comes to finishing, CERABIEN™ ZR FC Paste Stain is a great option.

KATANA Zirconia YML: A Testament to Innovation in Dental Materials

KATANA Zirconia YML stands at the forefront of dental material technology, offering outstanding aesthetics, strength, and efficiency. Its introduction has marked a significant advancement in the capabilities of dental technicians, allowing for the creation of restorations that truly mimic the beauty of natural teeth in a fraction of time.

As the dental industry continues to evolve, KATANA Zirconia YML remains a testament to the relentless pursuit of excellence in restorative dentistry.

For more detailed information on KATANA Zirconia YML, including technical guide, FAQs and Clinical cases, visit Kuraray Noritake Dental's YML dedicated page.

Interested in articles, user experience or clinical cases using KATANA Zirconia YML? Check the blog section of our website! 

Mathias Fernandez Y Lombardi

EU Scientific Manager
Dental Ceramics & CAD/CAM Materials
Kuraray Europe GmbH

Welcome to the latest edition of BOND Magazine, your essential guide to cutting-edge advancements and techniques in the world of dentistry. Volume 11 is packed with insightful articles, expert interviews, and practical advice designed to enhance your dental practice or laboratory and keep you at the forefront of the profession.

In this issue, we dive into the simplicity and predictability of the flowable injection technique with Michał Jaczewski. Learn how this minimally invasive method can transform patient outcomes with minimal preparation, making it accessible for both beginners and experienced practitioners alike.

We also explore the transformative potential of universal resin cement in Prof. Lorenzo Breschi's article, which introduces a third application mode that could revolutionize how you approach luting for challenging restorations.

Meanwhile, Dr. Michael Braian shares his comprehensive guide to dental rehabilitation using digital workflows, ensuring you can leverage the latest technology for superior patient care.

This volume also includes a case reports by Dr. Jose Ignacio Zorzin - discussion on rationalizing clinical procedures with universal adhesives. These insights will help streamline your workflows, reduce chair time, and enhance patient satisfaction.

From detailed explorations of high-performance materials to interviews with leading dental laboratory professionals like Alexander Aronin and Andreas Chatzimpatzakis, BOND Magazine offers a wealth of knowledge for all dental professionals.

Click here to read. Enjoy reading, and let us inspire your journey towards excellence in dentistry.

Start Reading: BOND | VOLUME 11 | 07/2024

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