Clinical case by Dr. Frank Heldenbergh

The advancements in zirconia in contemporary dentistry nowadays allow for a wider range of applications, including in the anterior sector, and for chairside production using dedicated CAD/CAM systems. Even without a cutback, KATANA™ Zirconia Block (STML), combined with CERABIEN™ ZR FC Paste Stain (both Kuraray Noritake Dental Inc.), offer an extremely satisfactory aesthetic solution.

In the present patient case, the materials were chosen to replace old PFM crowns on the maxillary central incisors. The planned treatment was in accordance with the patient's wishes, and carried out in a single appointment.

CASE DESCRIPTION

The patient asked for a replacement of the existing crowns on the two maxillary central incisors (teeth 11 and 21, FDI notation). The porcelain-fused-to-metal (PFM) restorations had been in place for about thirty years (Figure 1). She desired aesthetic improvements and slight repositioning of these two teeth.

TREATMENT PLAN

In agreement with the patient, it was decided to perform the entire procedure in one appointment: removal of the existing crowns, digital impressions, production, and bonding of new restorations. The periodontium was healthy with no bleeding. The only uncertainty was whether the existing crowns were cemented onto inlay-cores or if they were Richmond crowns. A preliminary silicone impression was taken as a precautious measure: in case something unexpected prevented the new crowns from being bonded during the session, it would be easily possible to produce temporary crowns.

Fig. 1. Initial clinical situation.

TREATMENT

Using a diamond bur followed by a tungsten carbide bur, the existing crowns were removed, revealing that they indeed were Richmond crowns. Because the anatomy of the intra-radicular posts clearly contraindicates an attempt to remove these posts, it was decided to trim the crowns to transform them into inlay cores rather than risk further damage. The corono-peripheral preparations were reworked at the same time. One of the major challenges was related to the necessity of masking the metal of the transformed coronal-radicular reconstructions. Luckily, the space available was sufficient for the production of full zirconia crowns with a significant thickness (Figure 2). The target shade of the crowns was chosen in consultation with the patient (Figure 3).

Fig. 2. Situation after removal of the existing restorations.

Fig. 3. Shade determination using a shade tab: A2 was the appropriate shade.

Subsequently, impressions were taken using and intraoral scanner, the virtual models were checked and the crowns designed, considering the patient's request to have her two incisors slightly retracted (Figures 4 and 5).

Fig. 4. Virtual models of the patient’s teeth with the newly designed crowns, revealing the space available for a slight retraction.

Fig. 5. Designing of the two crowns.

The two crowns were milled from KATANA™ Zirconia Block 14Z A2 (Figure 6). A quick reminder: unlike lithium disilicate, zirconia prosthetic parts cannot be tried in immediately after milling, as they are around 20 percent larger than their final size after sintering. Final sintering was performed within about 18 minutes using the furnace SINTRA CS (ShenPaz Dental Ltd). After this process, the crowns may be tried on to check their fit, shape, shade and optical integration.

Fig. 6. Milled crowns in the CAD/CAM blocks.

For finishing of the restorations, different options are available. In this case, we decided not to limit ourselves to mechanical polishing of the prosthetic parts, as zirconia does not fluoresce like natural teeth. To add fluorescence as an optical feature, the surface was lightly stained and glazed with CERABIEN™ ZR FC Paste Stain (Figure 7).

Fig. 7. Crowns in the furnace after staining and glazing with liquid ceramics.

After firing, the two incisor crowns were tried in again using a try-in paste corresponding to the chosen resin cement system (PANAVIA™ V5, Kuraray Noritake Dental). In this way, the final appearance was simulated to validate the shade of the cement. The intaglio surfaces of the crowns were then sandblasted before applying CLEARFIL™ CERAMIC PRIMER PLUS as the restoration primer. The prepared teeth were treated with KATANA™ Cleaner (Kuraray Noritake Dental Inc.) to decontaminate the surface from proteins in saliva and possibly blood. Those clean surfaces are ideal for bonding. After thorough rinsing and drying, PANAVIA™ V5 Tooth Primer (containing MDP monomer for bonding with the hydroxyapatite and metal of the preparation) was applied according to the manufacturer’s instructions (Figure 8).

Fig. 8. Selected cementation system and try-in.

Subsequently, PANAVIA™ V5 Paste was applied into the first crown, which was then seated, followed by tack curing (brief photopolymerization for three to five seconds), excess removal and final light curing from all sides.

The procedure was then repeated for the second maxillary central incisor. The result instantly satisfied the patient, both in terms of aesthetics (adaptation, position of the new crowns, mimicry) and the comfort provided (Figures 9 and 10).

Fig. 9. Crowns immediately after placement.

Fig. 10. Aesthetically pleasing and comfortable result.

At a recall after four months, soft tissue conditions were ideal and the patient was happy with the outcome (Figures 11 to 13). The selected zirconia had nice optical properties, masking of the metal posts was successful and the natural surface texture contributed its share to a nice overall picture. The retracted position of the teeth was also perceived positively by the patient, while comfort and function were excellent.

DISCUSSION

Although lithium disilicate has so far been considered the material of choice for prosthetic work in the anterior region, zirconia is nowadays proving to be an extremely satisfactory alternative from every point of view: milling, strength, aesthetics, assembly (among other things, no hydrofluoric acid is required for bonding). KATANA™ Zirconia Blocks (STML) with a multi-layered colour structure in a single 4Y-TZP zirconia block, combined with CERABIEN™ ZR FC Paste Stain, offer a remarkable solution. This applies to treatments around the replacement of existing crowns as well as first-line treatments with less invasive preparations (verti-prep) than those required by other types of ceramics.

Fig. 11. The patient’s smile at a recall after four months.

Fig. 12. Great optical integration.

Fig. 13. Natural surface texture contributing to success Control pictures after four months taken by Emmanuel Charleux.

Een gemakkelijke procedure en een betrouwbaar resultaat; dát zien de meeste tandheelkundige praktijkbeoefenaren het liefst als ze een indirecte restauratie plaatsen. Aan de hand van onderstaande klinische casus wordt een gemakkelijk, maar uiterst succesvol klinisch protocol gepresenteerd voor de bevestiging van een lithiumdisilicaat-kroon.

Afb. 1.  Lithiumdisilicaat-kroon na het etsen van het intagliooppervlak met hydrofluoridezuur en try-in.

Afb. 2a.  Applicatie van KATANA™ Cleaner in de kroon voor volledige verwijdering van contaminanten zoals eiwitten van bloed en speeksel, die afbreuk kunnen doen aan de werking van een composietcementsysteem.

OF Afb. 2b.  Als alternatief wordt KATANA™ Cleaner in een mengbakje geappliceerd.

Afb. 3. Aanbrengen van KATANA™ Cleaner op de restauratie.

Afb. 4. KATANA™ Cleaner wordt op dezelfde manier aangebracht op de geprepareerde tandstructuur (tien seconden wrijven, gevolgd door spoelen en drogen).

Afb. 5. Aanbrengen van PANAVIA™ SA Cement Universal in de gereinigde kroon.

Afb. 6. Het cement bevat een uniek silaankoppelmiddel - het LCSi-monomeer - voor een sterke en betrouwbare bevestiging aan lithiumdisilicaat en andere restauratieve materialen zoals glas- en hybridekeramiek.

  Het silaan wordt in de mengpunt geactiveerd door Original MDP

Afb. 7. Gemakkelijke reiniging na twee tot vijf seconden tack-curing.

Afb. 8. De cementovermaat heeft een gelachtige consistentie en wordt in z‘n geheel verwijderd met een sikkelsonde.

FINAL SITUATION

Afb. 9. Resultaat van de behandeling meteen na plaatsing van de kroon.

Dentist:

RICHARD YOUNG DDS

MET DANK AAN RICHARD YOUNG,  DDS IN SAN BERNARDINO, CA,  VOOR DE CASUS EN BEELDEN

Case by Aleksandra Łyżwińska DMD, Warsaw, Poland

Dental injuries can be stressful for patients, parents of pediatric patients, and dentists alike. The following tips offer support in turning the treatment of crown fractures into a simple, quick and predictable procedure. In the case described, we opted for a reattachment of fractured crown fragments.

YOUNG PATIENT WITH A FRACTURED CENTRAL INCISOR

A 16-year-old patient presented immediately after an accident. Her maxillary left central incisor was fractured, involving half of the coronal enamel and dentin (Fig. 1). The pulp was not involved, but the fracture line was quite close to the pulp (Fig. 2). After examination and radiographic evaluation, the patient was anesthetized. When placing the rubber dam, it tore between the left central and lateral incisor (Figs. 3 and 4). Due to the patient’s young age and limited willingness to cooperate, the decision was made to proceed without replacing the rubber dam. This was expected to work well in this specific region due to the limited flow of saliva from the palate and a low associated risk of contamination.

Fig. 1. Fractured maxillary left central incisor at the day of the accident.

Fig. 2. Occlusal view of the maxillary anterior teeth with the pulp of the fractured central incisor shining through.

Fig. 3. Rubber dam placed and torn between the left central and lateral incisor.

Fig. 4. Occlusal view of the teeth isolated with rubber dam.

REMOVAL OF UNSUPPORTED ENAMEL PRISMS

In order to provide for a high-quality bond and natural aesthetics, unsupported enamel prisms should be removed. As the use of burs might be too invasive (removing too much structure) and thus hinder the alignment of crown fragments, air-abrasion with 50 μm alumina particles was the method of choice. To avoid iatrogenic pulp exposure, the deepest part of the affected tooth was protected with a colored flowable composite before sandblasting (Fig. 5). The adjacent teeth were protected using a metal strip (Fig. 6). Several seconds of air abrasion were sufficient to remove the enamel prisms and obtain a homogeneous enamel surface (Fig. 7). Subsequently, the colored flowable composite was removed from the dentin surface and the tooth fragment was treated in the same way.

Fig. 5. Preparations for sandblasting: Dentin area near the pulp protected with flowable composite.

Fig. 6. Protection of the adjacent teeth with a metal strip.

Fig. 7. Homogeneous enamel surface after air abrasion.

JOINING OF THE FRAGMENT WITH THE REMAINING TOOTH STRUCTURE

After air-abrasion treatment, the fit of the tooth and the fragment was checked and approved (Fig. 8). To improve retention of the fractured crown portion, it was bonded to a micro applicator using composite resin. Alternatively, prefabricated prosthetic carriers may be used. Then, selective etching of the enamel was performed on the tooth and the fragment (Figs. 9 and 10). During this procedure, the adjacent teeth were protected with a celluloid strip (Fig. 11). To better adapt the strip to the distal surface, a curved wedge was placed interproximally (Fig. 12).

The bonding system of choice was CLEARFIL™ SE Bond 2 (Kuraray Noritake Dental Inc.). After applying this adhesive to the tooth and the fragment (Fig. 13), a small portion of CLEARFIL MAJESTY™ ES Flow Super Low (Kuraray Noritake Dental Inc.) in the shade A2 was applied to the part of the fragment treated with adhesive.* After careful repositioning of the fragment and while holding it in place with the micro applicator, the composite was light cured.

Fig. 8. Perfect fit of the fragment to the tooth.

Fig. 9. Selective etching of the enamel on the tooth …

Fig. 10. … and the fragment.

Fig. 11. Position of the wedge …

Fig. 12. … used for better adaptation to the distal surface.

Fig. 13. Fragment treated with CLEARFIL™ SE Bond 2 PRIMER and BOND, which were both carefully air-dried, while the Bond was also light cured.

Fig. 14. Fragment back in place.

Fig. 15. Occlusal view of the teeth with the reattached fragment perfectly fitting the mould.

EXCESS REMOVAL AND POLISHING

Excess composite was removed with a scalpel blade and abrasive discs. The entire restoration was then polished using TWIST™ DIA for Composite (Kuraray Noritake Dental Inc., Fig. 16). A nice optical integration was obtained immediately after finishing due to fact that the fragment was stored in water during the waiting time and treatment. As observed with teeth isolated with rubber dam during treatment, teeth undergo dehydration outside the oral cavity. The effect is much stronger in the latter setting, making a fragment become chalky white. By keeping the fragment in water, dehydration is limited to a minimum and it is possible to properly evaluate the aesthetic outcome. This has a positive impact on patient satisfaction. In the present case, the fragment and the tooth structure had a similar appearance, both showing a slightly increased brightness as a result of manipulation under rubber dam or in the air, respectively.

Fig. 16. Immediately after polishing, the fragment has almost the same brightness as the tooth thanks to water storage. A slight dehydration effect is visible.

TREATMENT OUTCOME

To achieve optimal aesthetics and long-lasting gloss, the composite was repolished one week later (Fig. 17). This was accomplished with a light blue high-shine rubber polisher of the TWIST™ DIA for Composite system, followed by polishing with diamond paste and a goat hair brush.

Fig. 17. Treatment outcome after one week.

Teeth previously isolated with a rubber dam and the fractured crown fragment had undergone rehydration and returned to their natural colour. The colour adaptation is satisfactory. Harmonious light reflections on the labial surface of the treated tooth a beautiful, natural shine have made the fracture site nearly invisible. In addition to aesthetic value, good therapeutic results were also achieved - the tooth responds appropriately to stimuli and is pain-free.

CONCLUSION

The described approach is a valuable treatment option for anterior trauma cases with relatively large fragments that are still available. By reattaching the natural structure, the need for complicated and time-consuming multi-shade layering and free-hand modeling is eliminated, while all the remaining natural tooth structure is saved. Instead of preparing the tooth, a removal of the unsupported enamel prisms and roughening of the surface is absolutely sufficient. Key elements for a great optical integration and long-lasting success are the proper use of a high-performance adhesive as well as the selection of a composite that has the ability to properly blend into its environment and offers a nature-like gloss retention. The selected materials offer precisely these features, so that the great outcome may be expected to last.

*CLEARFIL MAJESTY™ ES Flow Super Low is indicated for cementation purposes. The cementation of tooth fragments, however, is not explicitly mentioned in the instructions for use. The decision to use the product in this context was made by the dental practitioner in charge of the treatment.

Case by Dr. Jusuf Lukarcanin

For all cases that require a particularly bright tooth shade – e.g. children or patients with bleached teeth / asking for a bleached effect in their restorations – CLEARFIL MAJESTY™ ES-2 Universal in the shade UW is likely to be the first choice. The young patient aged 28 shown below asked for diastema closure including shape and shade correction: She wanted to have a brighter, more beautiful smile.

Fig. 1. Initial clinical situation.

Fig. 2. Shape and shade correction were desired in this case.

Fig. 3. Treatment outcome …

Fig. 4. … leading to the beautiful smile the patient desired.

Reasons for selecting universal white:

- Cases requiring a particularly high brightness or value

- Restorations in deciduous teeth

- Restorations in bleached teeth

Universal white properties:

- Well-balanced translucency

- High light-scattering effect

CONCLUSION

One universal composite, four shades: In the case of CLEARFIL MAJESTY™ ES-2 Universal, this portfolio is absolutely sufficient for single-shade restorations even in the aesthetically demanding anterior region. Properties such as a nice blend-in effect, a great polishability and gloss retention over time support dental practitioners in creating beautiful restorations. As shade determination may be based on very few criteria instead of a complex shade guide, the whole restoration procedure becomes less stressful and more efficient. Furthermore, with only four shades to stock and usually no blocker needed, the number of materials on stock is reduced, leading to facilitations in stock management as well.

Case by Dr. Enzo Attanasio

The introduction of new-generation composites, equipped with nanofillers and highly loaded, has opened doors to new techniques for managing direct and semi-direct restorations. In particular, over the last ten years, there has been a significant revolution in the world of flowable composites. Nowadays, these materials offer a filler percentage very similar to packable composites through precise interventions in resin matrix management. They come in various viscosities, offering numerous advantages both in terms of handling and clinical use, as well as beneficial mechanical and physical characteristics.

FLOWABLE INJECTION TECHNIQUE

This new era of flowable composites has seen the development of a technique known as the Flowable Injection Technique (also referred to as injection moulding). It enables dental practitioners to reproduce anatomical forms created by a dental technician in the laboratory through a diagnostic wax-up. The shapes planned on the model are transferred directly in the patient's mouth using transparent silicone matrices or indexes, into which the composite is injected through specific injection holes.

The main difference compared to traditional mock-ups is that the reproduced dental elements remain separate from each other. This technique provides predictable results identical to those developed on the technician's wax-up, requiring less chair time than direct veneering and offering a longevity similar to traditional composite restorations.

BENEFITS AND CHALLENGES

The major benefit of this technique is the faithful reproduction of morphological details that the technician creates on the diagnostic wax-up, which the clinician can reproduce with minimal effort. The restoration produced through the flowable injection technique, if all steps are followed correctly, requires minimal finishing by the clinican, who only needs to focus on polishing the composite.

However, one limitation is the difficulty in isolating the operative field, often requiring a split-dam technique or labial retractors, with all the associated adhesive challenges. The use of a rubber dam is only feasible if the peripheral dental tissues around the restoration are euchromatic, allowing the technician to create a wax-up with supragingival preparation margins.

Another compromise with the flowable injection technique is the management of the composite as a single mass. This makes it only possible to reproduce natural incisal translucencies typical of young patients by performing complex cutbacks and subsequent incisal painting. Without specific operator skills, the outcomes of this time-consuming manual procedure are unpredictable.

HYBRID TECHNIQUE: BEST.FIT

To leverage the advantages of both classical direct anterior restoration and flowable injection techniques and eliminate the limitations, a hybrid technique known as BEST.FIT (Buccal Enamel Shade Through Flow Injection Technique) has emerged. This technique allows the operator to manage the delicate phase of reproducing the buccal enamel layer of the anterior restoration through the flowable injection technique, keeping certain aspects in mind during the injection phase.

PROCEDURE

The transparent silicone key used for the creation of the buccal enamel layer is similar to the one used in the original flowable injection technique. The initial phase of restoration management follows all the classical steps of direct technique, requiring isolation with rubber dam. The palatal enamel layer is recreated with a highly translucent packable composite, and the palatal portion of the interproximal walls is produced using a suitable matrix system. Then, the core of the restoration is defined with opaque masses, creating mamelons and adding incisal effects. It's crucial to control the residual enamel thickness using a vestibular silicone index, aiming for about 0.3 mm of space. The buccal portion is finally reconstructed during the injection phase. The transparent silicone index created on the wax-up should be tested after each reconstruction phase to ensure passive insertion.

After creating the restoration core, the element to be injected is separated from the contiguous ones with thin PTFE tape. The transparent mask is then inserted, and fluid composite is injected through the injection holes to precisely reconstruct the buccal enamel thickness. The composite tip should be positioned at least halfway through the buccal surface, and the injection should be slow and controlled to avoid air bubbles in the material.

FINISHING

Following a 40-second polymerization vestibularly and occlusally, the transparent matrix is carefully removed, and excess interproximal composite above the PTFE tape as well as any remaining composite cylinder from the injection holes are removed. After completing all restorative elements, the rubber dam is dismantled, and composite excess is finished. After checking the occlusion, the composite is polished, usually requiring no further intervention.

CASE EXAMPLE

Fig. 1. Female patient with discoloured anterior restorations desiring a smile makeover.

Fig. 2. Close-up of her maxillary anterior teeth.

Fig. 3. Restorations in need of replacement: Lateral view from the right.

Fig. 4. Restorations in need of replacement: Lateral view from the left.

Fig. 5. Printed model based on a digital diagnostic wax-up based on a digital impression.

Fig. 6. Palatal silicone index produced for the conventional direct restoration steps.

Fig. 7. Transparent matrix with injection holes produced for the build-up of the buccal enamel layer using the flowable injection technique.

Fig. 8. Operative field isolated with rubber dam.

Fig. 9. Existing restorations removed and tooth surfaces roughened at the start of treatment.

Fig. 10. Palatal silicone index positioned intraorally for the build-up of the palatal wall.

Fig. 11. Checking of the space available in the vestibular area with a second silicone index.

Fig. 12. Etching with phosphoric acid etchant.

Fig. 13. Application of a universal adhesive (CLEARFIL™ Universal Bond Quick, Kuraray Noritake Dental Inc.).

Fig. 14. Palatal walls built up with CLEARFIL MAJESTY™ ES-2 Premium in the shade A1E with the aid of the palatal silicone index.

Fig. 15. Build-up of the interproximal walls with CLEARFIL MAJESTY™ ES-2 Premium in the shade A1D and establishing of the contact points using anatomical sectional matrices for the posterior area placed vertically.

Fig. 16. Dentin core built up with CLEARFIL MAJESTY™ ES-2 Premium in the shade A2D. CLEARFIL MAJESTY™ ES Flow Super Low in the shade XW was applied on the mamelons, while CHROMA ZONE™ COLOR STAIN Blue (Kuraray Noritake Dental Inc.) was used to reproduce incisal translucencies in the spaces not covered by the dentin core.

Fig. 17. Try-in of the transparent matrix for flowable injection.

Fig. 18. Isolation of the adjacent teeth with PTFE tape for a one-by-one injection.

Fig. 19. CLEARFIL MAJESTY™ ES FLOW Low in the shade A2 (Kuraray Noritake Dental Inc.) injected for the anatomical shaping of the maxillary right central incisor.

Fig. 20. Situation after flowable injection for all four anterior teeth, light curing through the matrix, final matrix removal and excess removal.

Fig. 21. Treatment outcome …

Fig. 22. … with visible mamelons, natural incisal translucencies …

Fig. 23. … and a lifelike anatomical shape …

Fig. 24. … of the restorations.

CONCLUSION

Each work phase must be executed with extreme care to lay the foundations for a passive linking of all subsequent steps without creating difficult management situations. The BEST.FIT technique is a convenient and useful method for dental practitioners to manage multiple direct anterior restorations simply and predictably, especially in situations requiring complex rehabilitations with large restorations.

Case by Dr. Jusuf Lukarcanin

In teeth in which the areas to be restored are surrounded by a lot of non-discoloured tooth structure - as may be the case in Class I, II and Class V cavities - the use of CLEARFIL MAJESTY™ ES-2 Universal in the shade U may be an option. The 28-year-old patient, who presented for diastema closure, had teeth with a comparatively low translucency and different shades due to smoking and excessive coffee consumption. As the composite was applied in enamel areas only, the relatively high translucency of the universal shade seemed beneficial in this case.

Fig. 1. Initial clinical situation.

Fig. 2. New smile of the patient.

Reasons for selecting universal:

- Large amounts of underlying or surrounding tooth structure present

- Medium light-scattering desired

Universal properties:

- High translucency

- Medium light-scattering effect

Case by Andreas Chatzimpatzakis

Observe and copy: This is the key to nature-like dental restorations. There are many optical effects, colour transitions and morphological details in natural teeth that need to be taken in and understood – and replicating them is only possible for those who know exactly how their materials work. Once these skills are acquired, however, they enable a dental technician to produce their restorations as truly beautiful copies of nature. Even when restoring a single maxillary central incisor, the technique delivers outstanding – or inconspicuous - outcomes, as revealed by the following example.

Using high-quality, translucent and gradient-shaded zirconia frameworks and porcelains, the layering technique does not have to be highly complicated. Two bakes and a number of selected effect liquids, internal stains and porcelains are usually sufficient for outcomes that exceed expectations.

CASE EXAMPLE

In the present case, a young male patient had a quite opaque crown on his maxillary right central incisor that needed to be replaced. During shade selection in the dental laboratory (Fig. 1), it was observed that the cervical third of the adjacent central incisor is lighter than the rest. Its shade in other areas corresponded to B4 on the VITA classical A1-D4^® Shade Guide. Hence, it was decided to use a somewhat lighter material for the framework and darken the restoration especially in the middle and incisal areas with internal stains.

The concrete plan was to mill a coping made of KATANA™ Zirconia STML (Kuraray Noritake Dental Inc.) in the shade A3, characterize it with Esthetic Colorant (both Kuraray Noritake Dental Inc.) and sinter the piece (Figs 2 to 4). In the following layering procedure including just two bakes, a combination of internal stains and selected porcelains (CERABIEN™ ZR, Kuraray Noritake Dental Inc.) was applied as illustrated in Figures 5 to 12. Figures 13 to 17 display the result on the model, minor adjustments during try-in and the final treatment outcome.

Fig. 1. Shade selection. The cervical third of the adjacent central incisor is lighter than usual compared to the middle and incisal areas.

Fig. 2. Coping made of KATANA™ Zirconia STML in the shade A3.

Fig. 3. Intensification of some shade characteristics of the multi-layered blank using Esthetic Colorant in the shades Grey (middle) and Blue and Grey (incisal area).

Fig. 4. Coping after sintering.

Fig. 5. Colour map for internal staining, using CERABIEN™ ZR Internal Stains.

Fig. 6. Result of the use of Shade Base Stain Modifier Fluoro to increase the fluorescence and internal staining as planned.

Fig. 7. Application of Opacious Body OBA2, …

Fig. 8. … Translucent Tx …

Fig. 9.: … and Luster CCV-2.

Fig. 10. Crown after the first bake.

Fig. 11. Crown after the application of CERABIEN™ ZR Internal Stains: A+, Aqua Blue 2, White mixed with Cervical 2 (ratio: 30/70) for the cracks, and Cervical 2.

Fig. 12. Application of Luster LT1 to finalize the shape.

Fig. 13. Finished crown after the second bake on the model.

Fig. 14. Evaluation of the surface texture: Observing and copying the surface details is as important as the imitation of the shade characteristics.

Fig. 15. Minor texture adjustments during try-in.

Fig. 16. Final restoration in place after cementation with PANAVIA™ V5 (Kuraray Noritake Dental Inc.).

Fig. 17. Treatment outcome.

CONCLUSION

Mastering the art of observing natural teeth is the key to lifelike restorations. It allows a dental technician to develop a deep understanding of shade and morphology, which is – apart from knowing the selected materials very well – the only talent needed to reach a high level of excellence. Those who are observant and take in every detail with their eyes can be sure that their mind will understand and their hands will automatically follow.

Case by Vasiliki Tsertsidou

What kind of resin composite is recommended for core build-up procedures? While there are specific dual-cure core build-up resin composites available on the market, it is not mandatory to use them. Light curing is advisable to be applied even for materials with dual-cure polymerization. Some conventional resin composites demonstrate more favourable properties for a core build-up compared to specific core build-up resin composites itself.¹ Hence, it is possible to utilize a composite generally used in the dental office, provided it is indicated to and it is not applied deep within the root canal, where proper light curing would be impossible. The critical material properties for core build-ups are high filler load, sufficient flexural modulus and flexural strength.

CLEARFIL MAJESTY™ ES-2 composite series (Kuraray Noritake Dental Inc.) are suitable option for this case. With a filler load weight percentage of 78 and a flexural strength of 118 MPa (according to manufacturer), CLEARFIL MAJESTY™ ES-2 Classic corresponds to core build-up prerequisites*. The following case is illustrating the clinical procedure.

*The indication range of CLEARFIL MAJESTY™ ES-2 composite does not cover core build-up. In the specific case it is used for creating a large Class II filling where all conditions from the IFU, such as curing depth, are met.

Fig. 1. Endodontically treated tooth with a vertical fracture of palatal wall on maxillary right second premolar.

Fig. 2. Buccal view of the tooth.

Fig. 3. Clinical image, directly after removal of fragment.

Fig. 4. Fragment of the maxillary right second premolar.

Fig. 5. Circumferential matrix band for build-up to assist endodontic retreatment.

Fig. 6. Build-up of the missing walls (margin relocation) with CLEARFIL MAJESTY™ ES-2 Classic (A3).

Fig. 7. Temporary filling of the cavity.

Fig. 8. Replacement of the temporary filling material with CLEARFIL MAJESTY™ ES-2 Classic.

Fig. 9. Crown preparation.

Fig. 10. Proximal carious lesion present on the adjacent fist premolar.

Fig. 11. Situation after rubber dam placement and caries removal.

Fig. 12. Cavity restored with CLEARFIL MAJESTY™ ES-2 Classic.

Fig. 13. Prepared crown.

Fig. 14. Crown after sandblasting of the intaglio.

Fig. 15. Mechanically cleaned abutment tooth ready for pre-treatment.

Fig. 16. Intaglio of the crown treated with CLEARFIL™ CERAMIC PRIMER PLUS.

Fig. 17. Etching of the composite surface with phosphoric acid gel.

Fig. 18. Air-drying of PANAVIA™ V5 Tooth Primer on the abutment tooth.

Fig. 19. Crown in place after cementation with PANAVIA™ V5 Paste and excess removal.

A GOOD CHOICE

Dual-cure core build-up resin composites are two-component materials that need to be mixed homogeneously, which obstracts composition from containing high filler load. However, to prevent deformation of the core, a highly filled composite is advisable. This better simulates the flexural modulus of natural tissues compared to materials with low filler load. Consequently, a light-curing material like CLEARFIL MAJESTY™ ES-2 might be a better option. Applied in 2-mm increments in the core area (and not in the root canal), it performs well and provides the desired outcomes. Additionaly, the option of utilising the same material as for any other type of direct restorations is simplifying the stock management and supporting dental practitioners striving for a simplification of clinical procedures.

References

1. Spinhayer L, Bui ATB, Leprince JG, Hardy CMF. Core build-up resin composites: an in-vitro comparative study. Biomater Investig Dent. 2020 Nov 3;7(1):159-166. doi: 10.1080/26415275.2020.1838283. PMID: 33210097; PMCID: PMC7646551.

Dentist:

VASILIKI TSERTSIDOU

Door dr. Clarence Tam, HBSC, DDS, AAACD, FIADFE

Het gebruik van porseleinveneers voor het verbeteren van de vorm, kleur en visuele stand van anterieure tanden is een gebruikelijke techniek binnen de esthetische tandheelkunde. Het biomimetische doel van de restauratie van tanden raakt niet alleen het cosmetische domein; functionele afwegingen spelen ook een rol. Het is essentieel om in acht te nemen dat de intacte omhulsels van de palatale en faciale wanden met betrekking tot anterieure tanden verantwoordelijk zijn voor de intrinsieke buigsterkte. Als de tandheelkundige structuur is aangetast door endodontische invloeden, cariës en/of trauma, moet al het mogelijke worden gedaan om de residuele structuur te behouden en moet er naar worden gestreefd om basisprestaties van een onaangetaste tand te herstellen of overstijgen.

ACHTERGROND

Een vrouwelijke 55-jarige ASA II-patiënt meldde zich bij de praktijk voor een whitening-behandeling. Naar verwachting zou de whitening geen effect hebben op de kleur van een reeds bestaande porseleinen facing op tand 1.2. Deze zou binnen de procedure moeten worden verwijderd, vooral als de kleurveranderingen significant zouden zijn. De patiënt begon met de basiskleur VITA* 1M1:2M1; verhouding 50:50 in het bovenste anterieure gedeelte en 1M1 in het onderste anterieure gedeelte. Na een nightguard-bleekprotocol met 10% carbamideperoxide, 3 tot 4 weken lang gedurende de nacht, werd bij de patiënt een VITA* 0M3-kleur bereikt in de bovenste en onderste tandbogen. Als gevolg daarvan was er een aanzienlijk verschil in value tussen tand 1.2 met facing en de omringende tanden; tevens werd een toegenomen chroma vastgesteld bij de contralaterale tand 2.2 vanwege een faciaal-gerelateerde Klasse III-composietrestauratie. Laatstgenoemde tand stemde qua formaat niet overeen met de contralaterale tand en daarom werd besloten om beide laterale snijtanden te behandelen met geprepareerde laminaatveneers van lithiumdisilicaat. De aangrenzende hoektand (2.3) vertoonde lokale milde tot matige slijtage van de cusps, maar de patiënt wilde hieraan niets laten doen totdat de nieuwe facings zouden zijn geplaatst. Het doel van smile design in deze fase is om uiteindelijk te zorgen voor tweezijdige harmonie met het oog op de plaatsing van een aanvullende indirecte restauratie waarmee het faciale volume en het gebrek van de cusp op tand 2.3 op korte termijn worden hersteld.

PROCEDURE

Een protocol voor een digitaal smile design was niet nodig voor de aanvankelijke opzet, namelijk de individuele behandeling van de laterale snijtanden. Een lichte variatie is toegestaan bij dit tanden van dit type, aangezien deze de lach van de patiënt karakteriseren qua sekse en persoonlijkheid. Voorafgaand aan de verdoving was de doelkleur geselecteerd aan de hand van close-upfoto's die zowel gepolariseerde als ongepolariseerde selecties toonden. De foto's waren geprepareerd voor digitale kleurkalibratie door middel van referentieopnamen met een neutrale 18% grijswit-balanskaart (Afb. 1).

Afb. 1. Referentieopname met neutrale 18% grijskaart.

De basisbodykleur was VITA* 0M2 met een perspiltint BL2. De patiënt werd verdoofd met 1,5 ampul met een 2% lidocaïne-oplossing met epinefrine (verhouding 1:100.000); daarna werd een cofferdam volgens de split-damtechniek geplaatst. De facing op tand 1.2 werd gesectioneerd en verwijderd van tand 1.2; vervolgens werd op tand 2.2. een minimaal invasieve veneerpreparatie uitgevoerd (Afb. 2). De gedeeltelijke vervanging van de oude composietharsrestauratie werd uitgevoerd op het mesioincisobuccopalatale aspect van tand 12, waarbij het intacte segment werd behouden. De adhesie aan de oude composiet werd bereikt door middel van abrasie met microdeeltjes en een silaankoppelproduct (CLEARFIL™ CERAMIC PRIMER PLUS). De randen werden bijgewerkt en de retractiedraden gedrenkt in een aluminiumchloride-oplossing en vastgezet. De kleuren van preparatiestompen werden vastgelegd. Er werden definitieve afdrukken gemaakt met behulp van licht en zwaar polyvinylsiloxaan in een metalen tray. De patiënt verliet de praktijk met een noodvoorziening en instructies om de kleur in het laboratorium in het bisquebake-stadium te controleren. De door het tandtechnische laboratorium vervaardigde modellen bevestigen het minimaal invasieve karakter van deze casus.

Afb. 2. Veneerpreparatie bij tanden 1.2 en 2.2.

Na ontvangst van de modellen werd de patiënt verdoofd en werden de noodvoorzieningen verwijderd. De preparaties werden gereinigd en geprepareerd voor bevestiging door abrasie van de oppervlakken met behulp van aluminiumoxidepoeder (27 micron) bij een druk van 30 tot 40 psi. De facings werden getoetst door middel van een heldere glycerinepasta (PANAVIA™ V5 Try-in Paste Clear, Kuraray Noritake Dental Inc.). De retractiedraden werden vastgezet en de intaglio-oppervlakken van de restauraties werden 20 seconden lang behandeld met een 5% hydrofluoridezuur, waarna een silaankoppelproduct met 10-MDP (CLEARFIL™ CERAMIC PRIMER PLUS) werd aangebracht (Afb. 3). Het tandoppervlak werd gedurende 20 seconden geëtst met een 33% orthofosforzuur en vervolgens gespoeld. Daarna werd een primer met 10-MDP (PANAVIA™ V5 Tooth Primer) op de tand aangebracht (Afb. 4) en conform de instructies van de fabrikant drooggeblazen.

Afb. 3. Aanbrengen van CLEARFIL™ CERAMIC PRIMER PLUS op de intaglio-oppervlakken van de facings.

Afb. 4. Applicatie van PANAVIA™ V5 Tooth Primer op de geëtste tandoppervlakken.

Na het aanbrengen van veneercement (PANAVIA™ Veneer LC Paste Clear) (Afb. 5) werd de facing vastgezet. De cementovermaat had een relatief vaste consistentie en hield de facing goed in positie tijdens alle handelingen om de rand in orde te brengen vóór een tack-cure van 1 seconde (Afb. 6).

Afb. 5. Aanbrengen van PANAVIA™ Veneer LC Paste Clear op de geprepareerde intaglio-oppervlakken van de facings.

Afb. 6. PANAVIA™ Veneer LC Paste meteen na bevestiging. Let op de stroperige, relatief vaste consistentie van het cement, waardoor het gemakkelijk kan worden verwijderd onder vochtige omstandigheden én in de gelfase.

Het cement ging over in een geltoestand, waardoor de cementovermaat kon worden verwijderd bij een minimale reiniging (Afb. 7). Voor de definitieve uitharding werden de randen gecoat met een heldere glycerinegel om de zuurstofinhibitielaag te verwijderen (Afb. 8).

Afb 7. Verwijdering van cementovermaat na tack-cure van 1 seconde.

Afb. 8. Definitieve uitharding van de facings, gelijktijdig vanuit het palatale en faciale aspect.

De randen werden afgewerkt en op hoogglans gepolijst, en de occlusie van de restauraties werd positief bevonden. De postoperatieve opnamen laten een voortreffelijke randintegratie zien (Afb. 9).

Afb. 9. Postoperatieve esthetische verwerking van facings op de tanden 1.2 en 2.2.

Na de behandeling laten gepolariseerde opnames zien dat de restauraties esthetisch en functioneel goed zijn opgenomen in de nieuwe lach (Afb. 10), in afwachting van de esthetische verbetering van tand 2.3 om te harmoniëren met de contralaterale hoektand.

EINDRESULTAAT

Afb. 10. Eindresultaat via een gepolariseerde opname na de behandeling.

Tandarts:

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.

Case by Martin Laurik, MDT

There are so many different restorative materials out there and so many design and finishing concepts available that it often seems difficult to select the best option for a specific case. Using an allrounder like KATANA™ Zirconia YML can facilitate decision making: It is a great choice for single- to multi-unit restorations, works on teeth and implants alike, and can be adapted to individual needs by selecting a suitable design concept and adequate finishing technique. In this way, it is even possible to solve aesthetically challenging cases as the one illustrated below.

Initial situation and temporization

This patient was in need for treatment after the loss of her maxillary right central incisor and the placement of an implant in this region. As a replacement of the restorations on the other three maxillary incisors was necessary as well, it was decided to produce four crowns made of the same material – KATANA™ Zirconia YML. For aesthetic evaluation of the restorations’ length, angulations and shape in the mouth and a functional test drive, the crowns were digitally designed in full contour and milled from PMMA in the determined tooth shade A2 (Fig. 1).

Fig. 1. Full-contour PMMA crowns on the master cast.

Design, milling and effect dyeing of the zirconia crowns

Once the appearance and functional aspects of the temporary restorations were approved by the patient and the restorative team, the definitive crowns were produced. Their design was based on the full-contour design of the temporaries; however, a facial reduction of 0.6 mm was carried out by the software to create space for individualization with a small layer of veneering porcelain. The crowns were then milled from a KATANA™ Zirconia YML disc in the shade A1 – approximately one shade lighter than the determined tooth shade. To mask the uneven colour from the tooth stumps and the implant abutment, the intaglio of the crowns was treated with Esthetic Colorant in the shade Opaque. Some individual and intensified colour effects on the vestibular surface were also created with Esthetic Colorant.

Internal staining and porcelain layering

To slightly adjust the chroma and lightness, a first layer of CERABIEN™ ZR Internal Stains was added, followed by a wash bake. After the application of a first layer of CERABIEN™ ZR porcelains (Body, Enamel and Translucent) and baking (Fig. 2) – the central incisors received a layer of A1B, the lateral incisors a mixture of A1B and A2B (slightly darker to provide for a better match with the canines) with LT1, LT Natural completing the picture – additional internal staining was carried out (Fig. 3). The final layer of CERABIEN™ ZR luster porcelains (LT1, ELT2 used on the convex line angles to achieve an external reflection) was added and fixed in a fourth bake (Fig. 4).

After adjustments and very rough polishing, a self-glaze firing programme was selected (firing temperature 915 °C, holding time 5 seconds). On the highly polished incisal and palatal parts of the crowns and for contact point adjustment, CERABIEN™ ZR FC Paste Stain Glaze was applied and fixed with the same bake. The finished crowns on the model are shown in Figure 5, while Figure 6 displays the final treatment outcome.

Fig. 2. Crowns milled from KATANA™ Zirconia YML with a facial cutback of 0.6 mm after individualization with Esthetic Colorant, sintering, internal staining and the application of a first layer of porcelain.

Fig. 3. This picture shows the subtle internal stain adjustment to the ceramic mostly on the incisal part.

Fig. 4. Crowns prior to final shape adjustments and polishing.

Fig. 5. Finished crowns on the model.

FINAL SITUATION

Fig. 6. Treatment outcome.

Easy approach to beautiful restorations

The presented approach is a relatively easy way of producing highly aesthetic anterior restorations. Using an allrounder zirconia combined with a few selected effect liquids, internal stains and luster porcelains, it is possible to achieve a great optical integration even in a situation where teeth and implants need to be restored. The natural shape and surface texture of the restorations plays an important role in this context, as does the base material – a naturally shaded, highly translucent zirconia.

Dentist:

MARTIN LAURIK, MDT

Martin started working as a dental technician in 2014. In the time since, he never stopped training and learning from renowned colleagues. Continuing education courses focused on dental ceramics and occlusion in the functional concept of Slavicek. Fascinated by the beauty of natural teeth, developing an understanding of their complexity and learning how to mimic nature’s design as closely as possible has always been his primary goal, while he is well aware that there is still a lot to be learned and explored on the road to excellence.