429 Too Many Requests

By Dr. Michał Jaczewski

Holdbarheden af en kompositrestaurering afhænger af mange faktorer. Nogle ligger uden for tandlægens indflydelsessfære og er stærkt patientrelaterede. For eksempel har typen af tandbørste og tandpasta, børsteteknik, kost, stimulanser og hygiejnevaner alle indflydelse på restaureringen. Det er dog helt op til tandlægen at følge den bedste pudse- og poleringsprotokol. 

Korrekt polering har til formål at fjerne det iltinhiberende lag og skabe en glat restaureringsoverflade. En korrekt poleret restaurering vil ikke absorbere farvestoffer fra mad, drikke eller stimulanser, der fører til misfarvning af kompositten, hvilket sikrer et holdbart æstetisk resultat af restaureringen. 

Polering af komposit er en proces, som man skal være særlig opmærksom på. Den består af flere trin og principper: 

• Brugen af pudseskiver giver en glat restaureringsoverflade, overskydende komposit kan fjernes, og restaureringen kan få sin endelige form. Det er vigtigt at huske at arbejde på en fugtig overflade med en maksimal hastighed på 5.000-10.000 omdrejninger i minuttet på et 1:1 tandlægehåndstykke.

• Der findes mange typer og former for poleringsgummiskiver på markedet. En af de mest universelle, der er designet specielt til komposit, er TWIST™ DIA for Composite. Sættet består af to stk. poleringsgummiskive med forskellige slibeevner. Den første (mørkeblå) bruges til indledende grovpolering, den andet (lyseblå) for afsluttende glans og glathed. Man skal huske på, at arbejdet med disse værktøjer skal udføres på en tør overflade uden vandkøling. Arbejde uden vandkøling indebærer en risiko for at irritere pulpa, så arbejdshastigheden skal begrænses til mellem 5000 og 10000 omdrejninger i minuttet, og for højt tryk skal undgås. 

• Det næste trin er at bruge en diamantpoleringspasta med en gradient på 1 til 5 mikroner. Det anbefales at bruge et poleringshjul til denne pasta. Børstetypen er ikke vigtig, men brug ikke stive børstehår, der kan ridse kompositten. Når der bruges poleringsbørste og poleringspasta kan man nå steder, der er svære at komme til, f.eks. det cervikale område og approximalfladerne. Foruden dette trin bruges en slibestrips med diamanter til at polere approximalfladerne mere præcist. Brug strips med lille slibeevne (Super Fine) for ikke at ændre kontaktpunkterne. 

• Et yderligere trin for at øge glansen af restaureringen og beskytte den mod misfarvning er en aluminiumoxidpasta med en poleringsbørste i bomuld. En sådan pasta, der oprindeligt er beregnet til keramik, giver en usædvanlig glat overflade og en høj glans på restaureringsoverfladen. Dette trin skal udføres i et tørt miljø ved en maksimal hastighed på 5.000-10.000 omdrejninger i minuttet. 

I alle teknikker, og altså også den flydende injektionsteknik, har poleringsniveauet indflydelse på holdbarheden og de optiske og æstetiske egenskaber af restaureringen. Der bør derfor afsættes tilstrækkelig tid til dette nøgletrin inden for tandrestaurering. Kompositter er kendetegnet ved forskellige sammensætninger og mængder af fillers, som ikke kun påvirker deres egenskaber, men også hvor let de kan poleres. I nogle tilfælde skal proceduren gentages flere gange for at opnå en “spejleffekt”. CLEARFIL MAJESTY™ ES Flow er en komposit, som er meget let at polere til et højt glansniveau på trods af det høje fillerindhold. Specielt tilpassede poleringsgummiskiver, børster og pastaer gør det nemt at skabe en glat overflade og bidrager dermed til et holdbart resultat. 

BEFORE

AFTER

3-YEARS RECALL

LAD DEM SKINNE, LAD DEM SMILE! 

Dentist:

MICHAL JACZEWSKI

Michał Jaczewski blev uddannet på Wroclaw Medical University i 2006 og driver i dag privat praksis i byen Legnica i Polen. Han har specialiseret sig i minimalt invasiv tandpleje og digital tandpleje og er grundlægger af Biofunctional School of Occlusion. Her holder han foredrag og afholder workshops med fokus på omfattende patientbehandlinger. 

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.

Interview med Michał Jaczewski

Den flydende injektionsteknik er ved at blive en populær teknik til æstetisk restaurering af flere tænder med flydende komposit. Michał Jaczewski er en anerkendt instruktør, som underviser tandlæger i de færdigheder, der er nødvendige for at bruge teknikken med succes. Han blev uddannet på Wroclaw Medical University (Polen) i 2006 og har drevet sin egen private praksis i byen Legnica siden 2011. Han er grundlægger af Biofunctional School of Occlusion, som uddanner folk inden for omfattende tandbehandlinger, og han brænder for æstetisk digital tandpleje. På International Dental Show 2023 i Köln viste han os, hvornår, hvorfor og hvordan han bruger flydende injektion på sin tandklinik.

Kan du beskrive teknikken med nogle få ord?

Den flydende injektionsteknik er en enkel, forudsigelig og gentagelig måde at restaurere tænder på med flydende komposit. Den er baseret på en wax-up, over hvilken der produceres et silikoneaftryk. Dette aftryk fungerer derefter som form til injektion af den flydende komposit, som lyshærdes gennem den transparente silikone. Den største fordel er, at denne teknik fungerer uden eller i nogle tilfælde med en meget minimal tandpræparation. Det er en minimalt invasiv teknik, der kan bruges af både begyndere og erfarne tandlæger. Når der bruges komposit med en velafbalanceret opacitet i en tykkelse på 0,3 mm og en særlig poleringsprotokol kan man få fremragende morfologiske og optiske resultater.

Hvornår begyndte du at bruge den flydende injektionsteknik, og hvad er dens vigtigste indikationer? 

Jeg begyndte at bruge teknikken i 2018. Den blev oprindeligt opfundet til at restaurere fronten, men i dag bruges den også med succes til posteriort. Efter min mening er den særligt nyttig, når formen på flere tænder skal korrigeres for at forbedre en patients smil, uanset om patienten er ung eller gammel. Det kan være tilfældet efter tandregulering. Tænderne bliver simpelthen rettet og derefter genoprettet til den perfekte form ved hjælp af denne non-invasive teknik. Jeg bruger også flydende injektion til “smile makeover”, til at genoprette slidte tænder og til at ændre den vertikale dimension af okklusionen i forbindelse med rekonstruktioner af hele munden. I sidstnævnte tilfælde kan restaureringen være midlertidig og bruges til en “prøvekørsel” på mellemlang til lang sigt. Men den kan også fungere som endelig restaurering.

Hvordan starter man, når man planlægger at restaurere en patients tænder med den flydende injektionsteknik?

Den vigtigste fase, der har stor indflydelse på succesen med denne teknik, er planlægningsfasen. Den består af indhentning af dokumentation, aftrykstagning og fremstilling af en wax-up og mock-up samt produktion af silikoneaftrykket. Man kan selvfølgelig arbejde på traditionel vis med silikoneaftryk og konventionel wax-up, men brugen af digitale teknologier i denne fase vil forbedre arbejdsprocessen betydeligt. Jeg starter som regel med foto- og videodokumentation og et digitalt aftryk. Der er også behov for at registrere den centriske relation og okklusionen. Derefter laves en virtuel wax-up ved hjælp af et software til digitalt smiledesign. I dette trin er det vigtigt at tage hensyn til patientens ansigtstræk, hvilket bedst udføres ved hjælp af facial flow-konceptet. Baseret på det resulterende design kan et virtuelt behandlingsresultat vises og diskuteres med patienten. Når wax-up-modellen er godkendt, printes den i forskellige versioner: den fulde wax-up-model og en “interlip-model” med et skiftende design - en tand med wax-up efterfulgt af en tand uden. Disse modeller bruges til at fremstille de nødvendige indekser af gennemsigtig silikone. 

Digitalt smiledesign: Patient med alvorligt tandslid. 

Virtuel wax-up, der vises i patientens mund. 

Modeller printet på baggrund af den virtuelle mock-up. 

Silikoneindeks produceret på den skiftende (interlip) model

Hvornår og hvorfor producerer man mere end ét silikoneindeks? 

Det er særligt nyttigt at arbejde med det komplette og det skiftende (delvise) silikoneaftryk, når man planlægger at restaurere alle tænder i overkæben. Det giver mig yderligere stabilitet at starte med det skiftende aftryk, og det lægger grundlaget for et præcist resultat, især med hensyn til den planlagte okklusionshøjde. I underkæben, hvor håndteringen af aftrykket og kompositten er vanskeligere på grund af tilstedeværelsen af spyt og bevægeligt blødt væv, anbefaler jeg altid at opdele arbejdsområdet i tre sektioner - en anterior og to posteriore regioner - og arbejde på dem separat. 

Hvordan forbereder man tænderne og injicerer den flydende komposit?

I de fleste tilfælde har vi kun brug for at gøre emaljeoverfladerne ru i forbindelse med bindingsproceduren, hvilket normalt er muligt ved luftslibning med aluminiumoxid (50 µm ved lavt tryk). Derefter ætses emaljen med fosforsyre og et universelt bindingmiddel påføres. Silikoneindekset er udstyret med et injektionshul på den incisale kant. Dette gøres nemt med kanylen fra sprøjten med den flydende komposit, der presses gennem materialet fra indersiden til ydersiden. I den posteriore region kan det være nyttigt at bruge et hårdere materiale og integrere to huller for hver tand på separate cuspis - et til injektionen og et til det udadgående flow. Hvis indekset er hårdt, er det nødvendigt med en diamantbor til denne procedure. Jeg placerer aftrykket, injicerer den flydende komposit fra bunden til toppen, lyshærder materialet kortvarigt og fjerner aftrykket. Den endelige polymerisering udføres efter fjernelse af aftrykket og påføring af et lag glyceringel. Når alt overskydende materiale er fjernet, og den proksimale del af restaureringen er helt færdig, gentages proceduren for de andre tænder, før restaureringerne poleres. 

Har du nogle favoritprodukter til denne teknik?

Til silikoneaftrykketbruger jeg EXACLEAR (GC), da det er den mest transparente silikone, der findes på markedet. Min foretrukne komposit til den flydende injektionsteknik er CLEARFIL MAJESTY™ ES Flow med lav viskositet (Kuraray Noritake Dental Inc.). Jeg har haft mulighed for at teste mange forskellige produkter, såvel på min tandklinik som i forbindelse med mine kurser. I den forbindelse fandt jeg ud af, at materialet fra Kuraray Noritake Dental har visse fordele. Det er en moderne type nanokomposit med en bred vifte af indikationer og et stort udvalg af nuancer. Med sine tre viskositeter kan det bruges i mange forskellige kliniske situationer. Jeg begyndte at bruge det for fem år siden, og til den flydende injektionsteknik er Lowvarianten mit første valg, da det er den mest universelle, der er egnet til anteriore og posteriore tænder. De mest afgørende fordele, der påvirkede min beslutning om at bruge den, er dens naturlige æstetik og overlegne polerbarhed. Du kan opnå en spektakulær effekt uden særlige færdigheder. Som bindingmiddel foretrækker jeg at bruge CLEARFIL™ Universal Bond Quick, som gør arbejdsprocessen endnu nemmere, hurtigere og mere forudsigelig. Til polering har jeg udviklet min egen protokol. 

Hvordan efterbehandler og polerer du dine restaureringer? 

Jeg starter i det proksimale område med poleringsstrips og somme tider også en proksimal sav. Til formjusteringer har tre forskellige diamant- og karbidbor vist sig at være gode. Derefter fortsætter jeg med fine eller ekstra fine Sof-Lex™ Finishing and Polishing Discs (3M), der bruges til konturering og efterbehandling, og gummipolerer TWIST DIA™ for Composite (Kuraray Noritake Dental Inc.), som allerede skaber en flot, naturlig overfladeglans med en lille indsats. Derefter bruger jeg et børstehjul af gedehår med diamantpoleringspasta (Diamond excel, FGM), og til sidst bruger jeg et bomuldshjul sammen med en aluminiumoxidpoleringspasta (Pasta Grigia II, anaxDENT). Dette giver mulighed for at opnå en spejlblank finish. 

Ætsning af emaljen med fosforsyre

Komplet silikoneaftryk på plads. 

Påføring af CLEARFIL™ Universal Bond Quick. 

Situation umiddelbart efter injektion af CLEARFIL MAJESTY™ ES Flow (Low), lyshærdning og fjernelse af silikoneaftrykket.

Proksimale justeringer med roterende instrumenter. 

Hvad er de største fordele ved den flydende injektionsteknik? 

De største fordele for patienter og tandlæger er besparelser i tid og penge. Mange patienter har ikke råd til keramiske facader, og de er meget glade for at få tilbudt et alternativ af høj kvalitet, der kan leveres efter en enkelt konsultation. Proceduren er uden præparation og restaureringerne kan let repareres eller farven ændres, hvis man ønsker det, så der er stort set ingen risiko forbundet med behandlingen. Tandlæger kan normalt allerede begynde at behandle patienter, efter at de har deltaget i et enkelt kursus. Øvelse gør mester, men de første resultater er ofte allerede ret imponerende, så der er ikke tale om en stor investering for begyndere - hverken i tid eller i nye materialer. Selvfølgelig kan du bruge masser af tid på efterbehandling og polering, men jeg er sikker på, at du vil finde den rette balance mellem arbejdsindsats og resultat.

Sæt af instrumenter til den flydende injektionsteknik.

Har du anbefalinger til, hvordan man kommer i gang med at bruge teknikken? 

Først og fremmest vil jeg gerne opfordre alle til en gang imellem at gå ud af deres komfortzone og prøve noget nyt. For mig var det virkelig en gamechanger, da jeg begynde at arbejde med den flydende injektionsteknik, og jeg vil aldrig arbejde uden den igen. Før du begynder at bruge teknikken, vil jeg anbefale dig at deltage i et kursus, hvor du lærer al den teoretiske viden, der er nødvendig for at få succes med din første case, og måske endda deltage en praktisk workshop. 

Michał Jaczewski under sin præsentation på Kuraray Noritake Dentals stand i Köln. 

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.

Vigtigheden af protetikbehandling af høj kvalitet

Behandling af høj kvalitet er sandsynligvis det vigtigste element på vejen til patienttilfredshed. Under hvert eneste tandlægebesøg ønsker patienten at føle sig omhyggeligt plejet af en dygtig fagperson, mens tiden i stolen og antallet af aftaler bør reduceres til det nødvendige minimum. I forbindelse med protetiske behandlinger indebærer det, at en restaurering skal passe perfekt lige med det samme og være stabil over tid for at undgå omlavninger og ekstra tandlægebesøg.

Men hvordan er det muligt at levere restaureringer af høj kvalitet, der passer perfekt, hver eneste gang? Blandt de potentielle kilder til problemer med kvaliteten af indirekte restaureringer er almindelige fejltagelser begået i tandlægeklinikken eller laboratoriet, kommunikationsproblemer og – ofte overset – brugen af dental-zirkonoxid af lav kvalitet..

Zirkonoxid-restaureringer – en moderne og æstetisk dental løsning

For mere end 20 år siden kom zirkonoxid på dentalmarkedet som en erstatning for metal anvendt til at fremstille kroner og broer. Begge materialer – zirkonoxid og metal – blev sædvanligvis kombineret med et lag porcelæn og dannede restaureringer med porcelæn påbrændt på metal eller porcelæn påbrændt på zirkonoxid. I de følgende år fokuserede flere førende producenter af dentalzirkonoxid (f.eks. Kuraray Noritake Dental Inc.) på materialeforbedringer. Disse forbedringer omdannede gradvist det oprindelige hvide/uigennemsigtige kernemateriale til et keramisk materiale med tandlignende optiske og fremragende mekaniske egenskaber. De seneste zirkonoxid-varianter, som fås med forskellige niveauer af translucens og styrke, betragtes som den bedst mulige behandlingsplan blandt et bredt udvalg af patienter og indikationer af mange tandlæger rundt omkring i verden. En af årsagerne er, at de kun kræver et lille eller intet lag af porcelæn. En anden er, at med en minimumsvægtykkelse giver de mulighed for tandbesparende præparationer, fordi de har en gunstig adfærd på langt sigt – altså hvis der anvendes et materiale af høj kvalitet.

Forskelle på kvalitet af dental-zirkonoxid

Kvaliteten af zirkonoxid-produktet kan variere afhængigt af forskellige faktorer såsom renheden af råmaterialerne (ikke blot zirkonoxid, men også alumina og yttria samt farveadditiver etc.), den nøjagtige kemiske sammensætning, kornstørrelsen og partikelfordelingen. Hvert eneste trin i fremstillingsprocessen af emner – fra pulverkompilering til støbning og præ-sintring – indvirker på den endelige kvalitet, dvs. også på zirkonoxidens mekaniske og optiske egenskaber.

Almindelige problemer, der opstår på grund af zirkonoxid af lav kvalitet

Hver gang der er noget galt med en restaurerings optiske egenskaber – med dens translucens, den generelle farve eller overgangen fra ét lag til det næste i emner med en farvestruktur i flere lag – så vil problemet blive åbenlyst efter den endelige sintringsprocedure i laboratoriet. Det kan være nødvendigt at omlave den, og til sidst vil skavanken måske blive identificeret under indprøvning, hvilken højst sandsynligt vil have en negativ indvirkning på patienttilfredsheden. Det samme gælder for tilfælde af forkert pasform på grund af inhomogeniteter i materialestrukturen, for eksempel. Hvad der er endnu værre, er en ringere biokompatibilitet, overfladekvalitet, kantstabilitet, bøjetrækstyrke eller frakturmodstandsevne. Disse problemer kan kun identificeres med testudstyr, som er meget dyrt og for det meste ikke tilgængeligt i tandlaboratorier. Det betyder, at fejl af denne slags som regel forbliver uopdagede, indtil der opstår et virkeligt, klinisk problem som f.eks. tilbagetrækning af tandkødet, øget plakakkumulering, kraftigere slitage eller en tidlig fejl, som kan forårsage smerter og ubehag.

Oversigt over potentielle problemer og kliniske konsekvenser for patienter

Certificering og standardisering af dental-zirkonoxid

Det er derfor, specialister har udviklet en ISO-standard (ISO 6872:2015), som beskriver in-vitro tests, som alle producenter af dental-zirkonoxid anvendt i Europa eller USA skal udføre for at opnå FDA-godkendelse og modtage CE-mærket. De beskrevne tests bruges til at måle bøjetrækstyrke og frakturmodstandsevne, som sandsynligvis er de to vigtigste egenskaber, der bestemmer adfærden på langt sigt af restaureringer fremstillet af materialet. Alle materialer, der anvendes i Europa eller USA, skal have bestået disse tests.

Sådan undgår du at cementere dentalzirkonoxidrestaureringer, der er af lav kvalitet, i dine patienters munde

Fremover bør alle, som bruger denne certificerede dentalzirkonoxid, være sikre på og i stand til at minimere materialerelaterede risici. Den stigende popularitet af dental-zirkonoxid har imidlertid tiltrukket sig opmærksomhed fra firmaer, som forsøger at få deres andel af kagen uden at udfolde de nødvendige anstrengelser, som er påkrævede for at garantere høj produktkvalitet og opnå certificering. Ikke-certificerede produkter, som ikke har CE-mærkning, har én ting til fælles: de udsætter helt sikkert din forretning og dine patienter for en risiko.

Så hvordan er det muligt for tandlægeklinikker at garantere kvaliteten af zirkonoxid-produkter? Den gode nyhed er, at der er nogle enkle regler til rådighed. Ved at følge dem kan du undlade at cementere dental-zirkonoxid-restaureringer, der er efterligninger eller af lav kvalitet, i dine patienters munde.

Undlad at cementere dentalzirkonoxidrestaureringer, der er efterligninger eller af lav kvalitet, i dine patienters munde.

Tre gyldne regler for at forsyne dine patienter med zirkonoxid-restaureringer af høj kvalitet:

• Bestil kun restaureringer, som er fremstillet i hjemlandet eller i en region med de samme standarder som din egen: restaureringer fremstillet i tandlaboratorier i for eksempel Kina skal opfylde lavere standarder (og har derfor ikke CEmærket), og de vil muligvis ikke leve op til dine forventninger.
• Snak med det laboratorium, du samarbejder med (i dit hjemland), om kilden til deres zirkonoxid: forhør dig om, at de køber zirkonoxid fra førende producenter (f.eks. Kuraray Noritake Dental Inc.) via autoriserede distributører eller forhandlere, som de virkelig kender.
• Undgå handler, som er for gode til at være sande: lave priser kan være fristende, men den endelige omkostning for en behandling kan blive endnu højere end normalt, når der opstår komplikationer.

Indvirkning på langt sigt for patienter ved brug af certificerede zirkonoxidrestaureringer

At sikre sig, at den zirkonoxid, der bruges i din tandlægeklinik, opfylder de højest mulige kvalitetsstandarder, er et vigtigt bidrag til patienttilfredshed i det lange løb. Selv om den indledende pris på zirkonoxid-restaureringer af høj kvalitet er noget højere end på arbejde af ringere kvalitet, så kan den samlede investering være lavere, når restaureringerne holder længere og omlavninger elimineres. Dine glade patienter vil sandsynligvis være mere optagede af at overholde reglerne for god mundhygiejne og desuden mere loyale, det giver en positiv indvirkning på dit omdømme og dit patientgrundlag.

Undersøg zirkonoxid-muligheder, og vælg produkter fra certificerede producenter

Hvis du ønsker at gå et skridt videre, kan du sågar sammenligne certificerede zirkonoxid-varianter fra forskellige producenter og opdage forskelle. Kuraray Noritake Dental Inc. er for eksempel en ud af meget få producenter af dental-zirkonoxid, som udfører hele fremstillingsprocessen inklusive produktion af råmaterialet internt. På den måde er virksomheden i stand til at kontrollere hvert eneste trin i proceduren og garantere en enestående produktkvalitet – uanset hvilken materialevariant der vælges. Med den tilgængelige portefølje bestående af KATANA™ Zirconia UTML (ultratranslucent flerlags), KATANA™ Zirconia STML (fremragende translucent flerlags) og den højtranslucente flerlags HTML PLUS samt YML (med yderligere styrke og translucensgraduering) er det muligt at dække praktisk talt enhver indikation.

Unlock the power of zirconia: perfect for adhesive cementation, the ideal material for a wide range of indications, and essential in minimal invasive dentistry. Time to trust zirconia bonding!

This article demystifies zirconia bonding, providing clear, practical steps to ensure long-term functionality and patient satisfaction, all based on scientific research. Master the three adhesion pillars: mechanical retention, chemical activation, and wetting capacity. Discover how to successfully prepare zirconia surfaces, avoid pitfalls like misapplying silica coating and silane, and choose proven bonding systems for optimal results. Optimise retention even with minimal tooth preparation and achieve reliable zirconia restorations. Say goodbye to doubts and hello to successful zirconia bonding!

Factors influencing retention

Loss of retention due to de-cementation or debonding is a common cause of dental prostheses' failure.  First, let’s have a look at how to cope with the three main factors significantly influencing retention: tooth preparation, restoration pre-treatment, and cement type/bonding.

Tooth preparation

The abutment tooth's height, angle, and surface texture must be considered to achieve sufficient retention and resistance from the preparation. The retention form counteracts tensile stresses, whereas the resistance counteracts shear stresses ⁴. With the proper preparation, a restoration resists dislodgement and subsequent loss.

Full coverage restorations

To achieve sufficient retention and resistance for full-coverage crowns, the tooth abutment should be at least 4 mm high, and the convergence angle should range from 6 to 12 degrees with a maximum of 15 degrees ^{1, 5-8}.

Source; Conventional cementation or adhesive luting - A guideline, Dr. A. Elsayed, Prof. Dr Florian Beuer 

Adhering to the tooth preparation guidelines is crucial for full-coverage restorations (e.g., crowns, and FDPs). These practical guidelines are designed to achieve the required retention and resistance to make conventional luting possible. However, optimal retention and resistance are, in reality, hard to achieve. An unwanted amount of sound tooth substance often should be removed to achieve a highly retentive preparation. Moreover, several studies^2,3 show that, in daily practice, the preparation angle often exceeds 15 degrees.

Minimal-invasive restorations

Minimal-invasive restorations, such as single retainer FDPs, veneers, table-tops and inlay-retained FDPs, are based on a non- or low-retentive preparation form. In this case, retention shifts from (macro-)mechanical to micro-mechanical and chemical, necessitating the use of adhesive techniques ^9-11. Even though the preparations for minimal-invasive restorations largely lack mechanical retention, the long-term success of these types of restorations is well-documented when using a suitable resin cement (e.g. PANAVIA™, Kuraray Noritake Dental, Japan), including a proper pre-treatment and bonding procedure ^{10, 11}.

In high-retentive situations, conventional luting is acceptable for full-coverage restorations*. In all other cases, choosing a resin cement is a better solution. With proper tooth preparation (e.g., shaping, (self-)etching, abrasion) and the right adhesive resin cement system, a non-retentive preparation form provides a reliable basis using mainly chemical retention and micro-mechanical retention instead of macro-mechanical retention.

*Please review the articles available regarding the debate over whether to use a conventional cementation procedure, adhesive cementing, or selective adhesive luting

Restoration pre-treatment

Zirconia is densely sintered and does not contain a glass phase. Therefore, it cannot be etched with hydrofluoric acid to create a micro-retentive etching pattern. In addition, silanes cannot effectively promote zirconia bonding. Several studies have shown that air abrasion with 50-µm alumina at a reduced pressure of 0.5 bar (0.05 MPa; 7 psi) will create a sufficient micro-retentive pattern¹² and greatly enhances the wetting capacity.

In addition to air abrasion, chemical coupling agents such as bifunctional phosphate resin monomers are used on air-abraded zirconia. Bonding with phosphate monomer-containing adhesive resin systems gives very reliable results^27,28. The use of phosphate monomer-based resin cement systems (e.g., Panavia [Kuraray Noritake Dental, Tokyo, Japan]) and/or phosphate monomer primers, such as CLEARFIL CERAMIC Primer Plus (Kuraray Noritake Dental, Tokyo, Japan)  on freshly air-abraded zirconia, offer the most reliable bonding methods today ^13,27,28. We therefor consider MDP-based composite resin cements the material choice for our bonding procedure. However, it must be stressed that contamination of the air-abraded zirconia with saliva, phosphoric acid or other contaminants will limit the formation of chemical bonds and, therefore, must be avoided.

Avoiding contamination

For optimal moisture control, absolute isolation of the working field is crucial. Minimising  the risk of contamination, avoiding exposure to oral fluids. Before restoration placement, a thorough cleaning of the abutment tooth is essential. Following trial placement, a meticulous recleaning step is recommended to remove any potential introduced contamination. KATANA Cleaner (Kuraray Noritake Dental, Tokyo, Japan) is an ideal choice due to its unique properties. Its slightly acidic pH of 4.5 allows for effective cleaning intraoral and extraoral adhesion surfaces. Additionally, the incorporation of MDP monomer technology makes it highly efficient. The MDP salt in this product effectively bonds with contaminants, breaks them down and results in easy removal by water rinsing.

Cement type/bonding

After pre-treatment of surfaces to optimise the , it is important to understand that the properties of highly translucent zirconia differ highly from those of earlier generation zirconia. Early-generation zirconium oxides, including 3 mol% yttrium oxide (3Y-TZP), are high in strength and low in translucency. With the increase in yttria, creating 4-5 mol% yttria, or higher, zirconium oxides, the number of cubic crystals increases, resulting in higher translucency but leading to a reduction in strength. Therefore, attention must be paid to zirconia type, material thickness, restoration type, and application area. These factors may influence the choice of cement based on the adhesive properties demanded for lasting restorations and high aesthetic outcomes.

PANAVIA™ V5

For a resin cement system to deliver a strong bond, it is not always enough to have it contain an appropriate adhesive monomer. It is necessary for that adhesive monomer to be polymerised effectively under different circumstances. The PANAVIA™ V5 system contains an innovative “ternary catalytic system” consisting of a highly stable peroxide, a non-amine reducing agent* and a highly active polymerisation accelerator. Since this catalytic system is amine-free, the hardened cement has unsurpassed colour stability. In addition, the highly active polymerisation accelerator, one of the components in PANAVIA™ V5 Tooth Primer, is not only an excellent reducer that promotes polymerisation effectively, but it is also capable of coexisting with the (in this product) acidic MDP. This makes it possible to create a single-bottle self-etching primer. This accelerator is also responsible for the so-called touch-cure reaction when it comes into contact with the paste. Resulting in the sealing of the dentin interface and, at the same time, allowing the paste to set even in situations where light curing is limited.

*PANAVIA™ V5 Tooth Primer applied and left for 20 seconds, followed by air drying.

The second primer in the PANAVIA V5 system is CLEARFIL™ CERAMIC PRIMER PLUS, which incorporates Kuraray Noritake Dental’s original MDP and a silane. This product is used to prime zirconia but is also an excellent choice for priming silica-based ceramics, composites, and metals.

CLEARFIL™ CERAMIC PRIMER PLUS, which contains the original MDP, applied and dried.

The PANAVIA™ V5 full adhesive resin cement system consists of all three above-mentioned components, always used in the same way, independent of the material, for a straightforward procedure to ensure reliable bonding. The PANAVIA^TM V5 systems offer try-in pastes to visualise the final results before final cementing and confirm the appropriate shade of the resin cement to be used.

PANAVIA™ VENEER LC

Offering a flexible workflow and high bondability of thin, translucent restorations like veneers but also inlays and onlays, PANAVIA™ Veneer LC was designed. It is a light-curing resin cement system allowing a long working time of 200 seconds under ambient light*. This allows multiple veneers to be placed simultaneously without racing against the setting. The final light-curing can be started anytime after positioning the provisions. The PANAVIA™ Veneer LC cementing system includes PANAVIA™ Tooth Primer and CLEARFIL CERAMIC PRIMER Plus as primers to chemically interact with the adhesive surfaces.

PANAVIA™ Veneer LC Paste applied and the laminate veneer seated. In this case six veneers were simultaneously placed during one session.

Unpolymerized excess paste removed with a brush. PANAVIA™ Veneer LC Paste is a light-cured type rein cement, designed to provide sufficient working time.

This photo shows the results after the final light curing. Since the excess cement was easily removed, there were almost no cement residues.

PANAVIA™ SA CEMENT Universal

Still, clinicians seek efficiency and effectiveness in everyday practice by using a straightforward but durable resin cement solution. PANAVIA™ SA Cement Universal is developed to offer this ease-of-use property without losing focus on bonding properties.  PANAVIA™ SA Cement Universal is developed with the original MDP monomer in the hydrophilic paste compartment, allowing for chemical reactiveness with zirconia and tooth structure. The other compartment contains the hydrophobic paste, to which a unique silane coupling agent, LCSi monomer, is added, which allows the cement to deliver a strong and durable chemical bond to silica-based materials like porcelain, lithium disilicate and composite resin*. Furthermore, PANAVIA™ SA Cement Universal is less moisture sensitive than full adhesive resin cement systems. This also makes it the ideal cement in situations where rubberdam isolation is difficult.

*The product is available in both auto mix and hand mix options.

*Old PFM bridge (shown here) removed, and existing preparations modified to accommodate a 3-unit KATANA™ Zirconia bridge. The upper right canine was prepared to receive a single-unit KATANA™ crown.

Before

After. Seating & Final Smile. PANAVIA™ SA Cement Universal and CLEARFIL™ Universal Bond Quick were used for cementation and bonding. “I love the ease of use and clean-up with PANAVIA™ SA Cement Universal, and its MDP monomer creates a strong chemical bond to the tooth structure and zirconia. CLEARFIL™ Universal Bond Quick has a quick technique without reducing bond strengths, releases fluoride and has a low film thickness. I simply rub CLEARFIL™ Universal Bond Quick into the tooth for a few seconds and air dry. There is no need to light-cure, since it cures very well with PANAVIA™ SA Cement Universal. The patient was very happy with the results. She loved that she no longer saw metal margins, and her smile was much more uniform and lifelike.” Dr. Kristine Aadland

*Images are a part of a case by Dr. Kristine Aadland; 3-Unit anterior maxillary

Bonding to zirconia in three steps

Over the last century, the popularity of highly translucent zirconia has skyrocketed due to its excellent properties and wide range of anterior and posterior clinical applications. Because zirconium oxide prostheses are, if processed correctly, antagonist-friendly and easy (and relatively inexpensive) to fabricate, the material keeps gaining popularity in dentistry.

Several steps need to be taken into account for reliable and durable bonding. Years of research on achieving high and long-term bond strength to zirconia have concluded into three practical steps, summarised as the APC concept¹³ as a reliable procedure guideline.

APC-Step A

Zirconia should be air-particle abraded (APC-Step A) with alumina or silica-coated alumina particles; the sandblasting or micro-etching procedure. Air abrasion with a chairside micro-etcher using aluminium oxide particles (size: up to 50 μm) at a low pressure of 0,5 bar (0.05 – 0.25 MPa) is sufficient.^14,18,25-27

APC-Step P

The subsequent step includes applying a special ceramic primer (APC-Step P), which typically contains specially designed adhesive phosphate monomers, onto the zirconia adhesive surfaces.^29,30 The MDP monomer has been shown to be particularly effective at bonding to metal oxides like zirconium oxide.

APC-Step C

Dual- or self-cure resin cement systems should be used to reach an adequate C=C conversion rate underneath the zirconia restoration since the lack of translucency in zirconia reduces light transmission.¹³ However, in cases where high-translucent zirconia (HTZr0₂) is used, the zirconia transmits light so that the shade of composite or resin cement might influence the final appearance of such restorations. It is, thereforebased on the individual situation and shade of the abutment tooth.

The APC zirconia-bonding concept is not limited to intra-oral situations and can also be applied in the laboratory for implant reconstructions that include cemented zirconia components.

Conclusion

Rapid developments in high-quality translucent zirconia have made the utility and reliability of adhesive cementing systems even more crucial. This applies to fully opaque restorations but also minimally invasive and ultra-translucent restorations of low thickness. In all cases, the longevity of the bonding and, thus, the provision directly affects patient  satisfaction. By taking into account the three primary parameters we have discussed in this article and following the predictable APC protocol, you will successfully realise durable bonded zirconia restorations from now on.

References

1. Ladha K, Verma M. Conventional and contemporary luting cements: an overview. J Indian Prosthodont Soc. 2010;10(2):79-88.
   
   
2. Nam, Y., Eo, M.Y. & Kim, S.M. Development of a dental handpiece angle correction device. BioMed Eng OnLine17, 173 (2018). https://doi.org/10.1186/s12938-018-0606-1

3. Florian BEUER, Daniel EDELHOFF, Wolfgang GERNET, Michael NAUMANN, Effect of preparation angles on the precision of zirconia crown copings fabricated by CAD/CAM system, Dental Materials Journal, 2008, Volume 27, Issue 6, Pages 814-820

4. Muruppel AM, Thomas J, Saratchandran S, Nair D, Gladstone S, Rajeev MM. Assessment of Retention and Resistance Form of Tooth Preparations for All Ceramic Restorations using Digital Imaging Technique. J Contemp Dent Pract. 2018;19(2):143-9.
   
   
5. Edelhoff D, Özcan M. To what extent does the longevity of fixed dental prostheses depend on the function of the cement? Working Group 4 materials: cementation. Clin Oral Implants Res. 2007;18 Suppl 3:193-204.
   
   
6. Güth JF, Stawarczyk B, Edelhoff D, Liebermann A. Zirconia and its novel compositions: What do clinicians need to know? Quintessence Int. 2019;50(7):512-20.
   
   
7. Smith CT, Gary JJ, Conkin JE, Franks HL. Effective taper criterion for the full veneer crown preparation in preclinical prosthodontics. J Prosthodont. 1999;8(3):196-200.
   
   
8. Uy JN, Neo JC, Chan SH. The effect of tooth and foundation restoration heights on the load fatigue performance of cast crowns. J Prosthet Dent. 2010;104(5):318-24.
   
   
9. Blatz MB, Vonderheide M, Conejo J. The Effect of Resin Bonding on Long-Term Success of High-Strength Ceramics. J Dent Res. 2018;97(2):132-9.
   
   
10. Chaar MS, Kern M. Five-year clinical outcome of posterior zirconia ceramic inlay-retained FDPs with a modified design. J Dent. 2015;43(12):1411-5.
    
    
11. Kern M, Passia N, Sasse M, Yazigi C. Ten-year outcome of zirconia ceramic cantilever resin-bonded fixed dental prostheses and the influence of the reasons for missing incisors. J Dent. 2017;65:51-5.

12. Kern M, Dr Med Habil, M. BONDING TO ZIRCONIA. Jerd_40. 3DOI 10.1111/j.1708-8240.2011.00403.x VOLUME 2 3 , NUMBER 2 , 2011

13. Blatz MB, Alvarez M, Sawyer K, Brindis M. How to Bond Zirconia: The APC Concept. Compend Contin Educ Dent. 2016 Oct;37(9):611-617; quiz 618. PMID: 27700128.

14. Blatz M.B., Oppes S., Chiche G., et al. Influence of cementation technique on fracture strength and leakage of alumina all-ceramic crowns after cycling loading. Quintessence Int. 2008; 39(1): 23-32

15. Burke F.J., Fleming G.J., Nathanson D., Marquis P.M. Are adhesive technologies needed to support ceramics? An assessment of the current evidence. J Adhes Dent. 2002;4(1)): 7-22

16. Blatz M.B. Sadan A., Maltezos C., et al. In vitro durability of the resin bond to feldspathic ceramics. AM J Dent 2004;17 (3):169-172

17. Blatz M.B., Bergler M. Clinical applications of a new self-adhesive resin cement for zirconium-oxide ceramic crowns. Compend Contin Educ Dent. 2012;33(10):776-781

18. Maggio M., Bergler M., Kerrigan D., Blatz M.D. Treatment of maxillary lateral incisor agenesis with zirconia-based all-ceramic resin bonded fixed partial dentures: a case report. Amer J esthet Dent. 2012;2(4):226-237
19. Ozer F., Blatz M.B., Self-etch and etch-and0rinse adhesive systems in clinical dentistry. Compend Contin Edus Dent. 2013;24 (1):12-20

20. Kern M., Thomson V.P., Bonding to glass infiltrated alumina ceramic: adhesive methods and their durability. J Prosthet Dent. 1995;73 (3):240-249

21. Kern M., Wegner S.M., Bonding to zirconia ceramics: adhesion methods and their durability. Dent Mater. 1998;14(1):64-71

22. Wegner S.M., Kern M. Long-term resin bond strength to zirconia ceramic. J Adhes Dent. 2000;2 (2):139-147

23. Blatz M.B., Sadan A., Martin J., Lang B. In vitro evaluation of shear bond strength of resin to densely-sintered high-purity zirconium-oxide ceramics after long-term sorage and thermos cycling. J Posthet Dent. 2004;9(4):356-362

24. Blatz M.B., Chiche G., Holst S., Sadan A. Influence of surface treatment and simulated aging on bond strength of luting agents to zirconia. Quintessence Int. 2007;38 (9):745-753

25. Quaas A.C., Yang B., Kern M., Panavia F 2.0 bonding to contaminated zirconia ceramic after different cleaning procedures. Dent Mater. 2007;23(4):506-512

26. Song J.Y., Park S.w., Lee K., et al. Fracture strength and microstructire of Y-TZP zirconia after different surface treatments. J Prosthet Dent. 2013;110(4):274-280

27. Koizumi H., Nakayama D., Komine F., et al. Bonding of resin-based luting cements to zirconia with and without the use of ceramic priming agent. J adhes Dent. 2012;14(4):385-392

28. Nakayama D., Koizumi H., Komine F., et al. Adhesive bonding of zirconia with single -liquid acidic primers and a tri-n0butylborane initiated acrylic resin. J Adhes Dent. 2010;12(4):305-310

29. Alnassar T., Ozer F., Chiche G., Blatz M.B. Effect of different ceramic primers on shear bond strength of resin-modified glass ionomer cement to zirconia. J Adhes Sci Technol. 2016;DOI:10.1080/01694243.1184404

30. Blatz M.B. Long-term clinical success of all-ceramic posterior restorations. Quintessence Int. 2002;33(6):415-426

31. Mante F.K., Ozer F., Walter R., et al. The current state of adhesive dentistry: a guide for clinical practice. Compend Contin Educ Dent. 2013;34:Spec 9:2-8

32. Ozcan M., Bernasconi M. Adhesion to zirconia used for dental restorations: a systematic review and meta-analysis. J Adhes Dent. 2015;17(1):7-26

33. Inokoshi M., De Munck J., Minakuchi S., Van Meerbeek B. Meta-analysis of bonding effectivenss to zirconia ceramics. J Dent Res. 2014;93(4):329-334

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: