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.

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.

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.

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

Dr. Clarence Tam, HBSC, DDS, AAACD, FIADFE

Porcelāna venīru izmantošana, lai uzlabotu un atjaunotu priekšējo zobu formu, toni un vizuālo stāvokli, ir izplatīta tehnika estētiskajā zobārstniecībā. Biomimētiskais mērķis zobu restaurācijā ir ne tikai kosmētikas joma, bet arī funkcionālie apsvērumi. Ir svarīgi atzīmēt, ka aukslēju un vaiga sieniņu neskartais emaljas apvalks attiecībā pret priekšējiem zobiem ir atbildīgs par tā iedzimto lieces pretestību. Ja zobu struktūra ir bojāta endodontiskas piekļuves, kariesa un/vai traumas dēļ, ir jādara viss iespējamais, lai saglabātu atlikušo struktūru un jācenšas atjaunot vai pārsniegt neapstrādāta zoba sākotnējo veiktspējas līmeni.

PAMATINFORMĀCIJA

55 gadus veca ASA II sieviete uz zobu balināšanu. Bija paredzēts, ka zobu balināšana neietekmēs jau esošā porcelāna zoba 1.2 venīra toni. Tas būtu jāapstrādā pēc procedūras, it īpaši, ja toņa vērtības izmaiņas būtu būtiskas. Pacientes sākotnējais tonis bija VITA* 1M1:2M1; 50:50 attiecībā augšējā priekšējā reģionā un 1M1 apakšējā priekšējā reģionā. Pēc nakts kapju balināšanas protokola ar 10% karbamīda peroksīdu, kas tika nēsātas naktī 3-4 nedēļas, pacientei izdevās panākt VITA* 0M3 toni gan augšējā, gan apakšējā arkā. Rezultātā radās ievērojama vērtību neatbilstība starp zoba 1.2 venīru un blakus esošajiem zobiem, un tika novērota palielināta hroma uz kontralaterālā zoba 2.2, ko izraisīja ar seju saistīta III klases kompozīta restaurācija. Šis pēdējais zobs arī pēc izmēra nesakrita ar kontralaterālo zobu, un tāpēc tika pieņemts lēmums abus sānu priekšzobus apstrādāt ar saistītiem litija disilikāta lamināta venīriem. Blakus esošajam acu zobam (2.3) bija lokalizēts viegls līdz vidējs smailes galu nodilums, taču kamēr netika uzlikti pašlaik apspriestie venīri. Smaida dizaina mērķis šajā posmā ir izveidot divpusēju harmoniju, lai tuvākajā laikā veiktu papildu netiešo restaurāciju, kas atjaunotu 2.3 zoba sejas formu un smailes galu deficītu.

PROCEDŪRA

Sākotnējai iecerei, kas bija individuāla sānu priekšzobu apstrāde, digitālais smaida dizaina protokols nebija nepieciešams. Šim zobu tipam ir pieļaujamas nelielas variācijas, kas ir smaida personības un dzimuma marķieris. Pirms anestēzijas mērķa toni izvēlējās, izmantojot fotogrāfijas, kurās bija gan polarizēta, gan nepolarizēta atlase. Fotogrāfijas tika sagatavotas digitālai toņa kalibrēšanai, uzņemot atsauces skatus ar 18% neitrāla pelēkā baltā balansa karti (1. attēls).

1. attēls. Atsauces fotogrāfija, kas uzņemta ar 18% neitrālu pelēko karti.

Pamata nokrāsa bija VITA* 0M2 ar lietņa toni BL2. Paciente tika anestēzēta, izmantojot 1,5 karpulas 2% lignokaīna šķīduma ar 1:100 000 epinefrīnu, pirms tika piestiprināts gumijas aizsargs sadalītā aizsarga orientācijā. Zoba 1.2 venīrs tika sadalīts un noņemts no zoba 1.2, un tika pabeigta minimāli invazīva venīrs sagatavošana uz zoba 2.2 (2. attēls). Daļēja vecās kompozītmateriāla sveķu restaurācijas nomaiņa tika pabeigta 12. zoba mesioincisobukopalatālajā aspektā, saglabājot neskartu segmentu. Saķere ar veco kompozītmateriālu tika panākta, izmantojot gan mikrodaļiņu abrāziju, gan silāna savienojošo līdzekli (CLEARFIL™ CERAMIC PRIMER PLUS). Piemales tika uzlabotas, un ievilkšanas auklas iemērktas alumīnija hlorīda šķīdumā un iepildītas. Tika reģistrēti sagatavošanas celmu toņi. Galīgie nospiedumi tika ņemti, izmantojot gan vieglo, gan smago polivinilsiloksānu metāla paplātē. Pacientei tika veikta pagaidu apstrāde, un viņa tika nosūtīta ar instrukcijām pārbaudīt toni laboratorijā apdedzināšanas stadijā. Laboratorijas sagatavotie modeļi pārbauda gadījuma minimāli invazīvo raksturu.

2. attēls. Venīra sagatavošana zobam 1.2, 2.2

Pēc gadījuma saņemšanas paciente tika anestēzēta un izņemts provizoriskais līdzeklis. Preparāti tika attīrīti un sagatavoti savienošanai, nopulējot virsmas, izmantojot 27 mikronu alumīnija oksīda pulveri ar 30–40 psi. Venīri tika novērtēti, izmantojot caurspīdīgu glicerīna pastu (PANAVIA™ V5 Try-in Paste Clear, Kuraray Noritake Dental Inc.). Ievilkšanas auklas tika iepildītas un restaurāciju dziļspieduma virsma apstrādāta, izmantojot 5% fluorūdeņražskābi 20 sekundes pirms 10-MDP saturoša silāna savienojošā līdzekļa (CLEARFIL™ CERAMIC PRIMER PLUS, (3. attēls)) uzklāšanas. Zoba virsma 20 sekundes tika kodināta ar 33% ortofosforskābi un noskalota. Uz zoba tika uzklāts 10-MDP saturošs gruntējums (PANAVIA™ V5 Tooth Primer (4. attēls). un nožāvēts gaisā saskaņā ar ražotāja norādījumiem. Tika ievietots venīra cements (PANAVIA™ Veneer LC Paste Clear) (5. attēls) un uzlikts venīrs. Cementa pārpalikums nebija slīdošs, un tas labi noturēja venīru visu piemaļu pārbaužu laikā pirms 1 sekundes sacietēšanas (6. attēls).

3. attēls. CLEARFIL™ CERAMIC PRIMER PLUS uzklāts uz venīra dziļspieduma virsmām.

4. attēls. PANAVIA™ V5 Tooth Primer uzklāšana uz kodinātām zobu virsmām.

5. attēls. PANAVIA™ Veneer LC Paste Clear tonis, kas tiek uzklāts uz sagatavotām dziļspieduma venīra virsmām.

6. attēls. PANAVIA™ Veneer LC Paste uzreiz pēc uzlikšanas. Ņemiet vērā cementa viskozo, neslīdošo raksturu, kas ļauj viegli noņemt gan mitrā, gan gēla fāzē.

Cements tika pārveidots gēla stāvoklī, kas atviegloja cementa pārpalikumu noņemšanu ar minimālu tīrīšanu (7. attēls). Pirms galīgās cietināšanas piemales tika pārklātas, izmantojot caurspīdīgu glicerīna gēlu, lai likvidētu skābekļa inhibīcijas slāni (8. attēls).

7. attēls. Liekā cementa noņemšana pēc 1 sekundes cietināšanas.

8. attēls. Venīra galīgā cietināšana vienlaicīgi no palatālā un sejas aspekta.

Piemales tika pabeigtas un pulētas līdz spīdumam, un restaurāciju oklūzija tika apstiprināta kā atbilstoša. Pēcoperācijas skati parāda izcilu estētisko marginālo integrāciju (9. attēls).

9. attēls. Pēcoperācijas estētiskā venīra integrācija uz zoba 1.2 un 2.2.

Novērtējot polarizēto fotogrāfiju, restaurācijas estētiski un funkcionāli ir labi integrētas jaunajā smaidā (10. attēls), tagad tiek gaidīta estētiskā zoba 2.3 augmentācija, lai tas atbilstu kontralaterālajam acu zobam.

GALA REZULTĀTS

10. attēls. Gala rezultāts ar polarizētu fotogrāfiju, veicot atkārtotu novērtēšanu

Dentist:

CLARENCE TAM

References

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

Augstas kvalitātes protezēšanas nozīme

Augstas kvalitātes ārstēšana, iespējams, ir vissvarīgākais faktors ceļā uz pacienta apmierinātību. Katrā vizītē pacients vēlas justies kvalificēta speciālista aprūpēts. Savukārt krēslā pavadītais laiks un vizīšu skaits ir jāsamazina līdz nepieciešamajam minimumam. Tas nozīmē, ka protezēšanas kontekstā restaurācijai nekavējoties ir perfekti jāpieguļ un laika gaitā tai jābūt stabilai, lai izvairītos no pārtaisīšanas un papildus apmeklējumiem.

Bet kā iespējams katru reizi nodrošināt perfekti pieguļošas, kvalitatīvas restaurācijas? Starp potenciālajiem netiešo restaurāciju kvalitātes problēmu avotiem var minēt bieži pieļautās kļūdas zobārstniecības kabinetā vai laboratorijā, komunikācijas problēmas un bieži vien zemas kvalitātes zobu cirkonija oksīda izmantošanu.

Cirkonija restaurācijas – mūsdienīgs un estētisks zobārstniecības risinājums

Vairāk nekā pirms 20 gadiem cirkonija oksīds ienāca zobārstniecības tirgū kā kroņu un tiltu ražošanā izmantotā metāla aizstājējs. Abi materiāli – gan cirkonija oksīds, gan metāls – parasti tika apvienoti ar porcelāna slāni, veidojot porcelāna, metālā izkausēta porcelāna vai cirkonijā izkausēta porcelāna restaurācijas. Turpmākajos gados vairāki vadošie zobārstniecības cirkonija oksīda ražotāji (piemēram, Kuraray Noritake Dental Inc.) koncentrējās uz materiāla uzlabojumiem. Šie uzlabojumi pakāpeniski pārveidoja sākotnējo balti necaurspīdīgo karkasa materiālu keramikas materiālā ar zobiem līdzīgām optiskajām un izcilām mehāniskajām īpašībām. Daudzi zobārstniecības speciālisti visā pasaulē uzskata jaunākos cirkonija oksīda variantus, kas pieejami ar dažādiem caurspīdīguma un stiprības līmeņiem, par labāko iespējamo ārstēšanas iespēju dažādiem pacientiem un indikācijām. Viens no iemesliem ir tas, ka tiem ir nepieciešams tikai neliels porcelāna slānis, vai vispār nav vajadzīgs. Cits iemesls ir tas, ka ar mazu minimālo sieniņu biezumu tie ļauj veikt konservatīvu zobu sagatavošanu, vienlaikus nodrošinot labvēlīgu ilgtermiņa kalpošanu – ar noteikumu, ka tiek izmantots augstas kvalitātes materiāls.

Zobu cirkonija kvalitātes atšķirības

Cirkonija produktu kvalitāte var atšķirties atkarībā no dažādiem faktoriem, piemēram, izejvielu tīrības (ne tikai cirkonija, bet arī alumīnija oksīda un itrija, kā arī krāsvielu piedevu utt.), precīza ķīmiskā sastāva, daļiņu izmēra un sadalījuma. Katrs solis sagatavju ražošanas procesā – no pulvera sagatavošanas līdz sagatavju presēšanai un sinterizācijai sastiprināšanai – ietekmē gala kvalitāti, t.i., arī cirkonija mehāniskās un optiskās īpašības.

Bieži sastopamās problēmas, ko izraisa zemas kvalitātes cirkonija oksīds

Ikreiz, kad kaut kas nav kārtībā ar restaurācijas optiskajām īpašībām – ar tās caurspīdīgumu, kopējo krāsu vai pāreju no viena slāņa uz nākamo sagatavēs ar daudzslāņu krāsu struktūru – problēma kļūs acīmredzama pēc sinterizācijas laboratorijā. Rezultātā var būt nepieciešamība pārtaisīt, kā arī defekts var tikt atklāts laikošanas laikā, kas, visticamāk, negatīvi ietekmēs pacienta apmierinātību. Tas pats attiecas uz gadījumiem, kad, piemēram, materiāla struktūras neviendabīgums izraisa neprecīzu piegulēšanu. Vēl sliktāk ir zemākas pakāpes bioloģiskā saderība, virsmas kvalitāte, malu stabilitāte, lieces stiprība vai izturība pret lūzumiem. Šīs problēmas var identificēt tikai ar testēšanas aprīkojumu, kas ir ļoti dārgs un parasti nav pieejams zobārstniecības laboratorijās. Tas nozīmē, ka šāda veida nepilnības parasti paliek neatklātas līdz rodas reāla klīniska problēma, piemēram, smaganu recesija, palielināta aplikuma uzkrāšanās, lielāks nodilums vai agrīns defekts, kas var izraisīt sāpes un diskomfortu.

Overview of potential problems and clinical consequences for patients

Zobu cirkonija sertifikācija un standartizācija

Speciālisti ir izstrādājuši ISO standartu (ISO 6872:2015), kurā aprakstīti in vitro testi, kas jāveic katram Eiropā vai ASV izmantotā zobārstniecības cirkonija ražotājam, lai saņemtu FDA apstiprinājumu un CE marķējumu. Aprakstītie testi tiek izmantoti, lai izmērītu lieces stiprību un izturību pret lūzumiem, kas, iespējams, ir divas vissvarīgākās īpašības, kas nosaka no materiāla izgatavoto restaurāciju ilglaicīgu darbību. Katram Eiropā vai Amerikas Savienotajās Valstīs izmantotajam materiālam ir jānokārto šie testi.

Kā izvairīties no zemas kvalitātes zobu cirkonija restaurāciju ievietošanas pacienta mutē

Ikvienam, kas izmanto šo sertificēto zobu cirkoniju, jābūt pārliecinātam un jāspēj samazināt ar materiāliem saistītos riskus. Tomēr zobu cirkonija pieaugošā popularitāte ir piesaistījusi to uzņēmumu uzmanību, kuri cenšas iegūt savu kumosa daļu, neveicot nepieciešamos pasākumus, lai nodrošinātu augstu produkta kvalitāti un nokārtotu sertifikāciju. Nesertificētiem produktiem, kuriem nav CE marķējuma, ir viena kopīga iezīme: tie noteikti rada draudus Jūsu uzņēmumam un pacientiem.

Ņemot vērā augstāk aprakstīto kā ir iespējams nodrošināt cirkonija produktu kvalitāti zobārstniecībā? Labā ziņa ir tāda, ka ir pieejami daži vienkārši noteikumi. Ievērojot tos, jūs varat izvairīties no viltotu vai zemas kvalitātes zobu cirkonija restaurāciju ievietošanas pacienta mutē.

Izvairieties no viltotu vai zemas kvalittes zobu cirkonija restaurciju ievietoanas pacienta mutē.

Trīs zelta likumi, lai nodrošinātu saviem pacientiem augstas kvalitātes cirkonija restaurācijas:

• Pasūtiet tikai tādas restaurācijas, kas ražotas vietējā tirgū vai reģionā ar tādiem pašiem standartiem kā jums: piemēram, Ķīnas zobārstniecības laboratorijās ražotām restaurācijām ir jāatbilst zemākiem standartiem (tātad tām nav CE marķējuma), un tās var neatbilst jūsu cerībām.
• Konsultējieties ar savu (vietējo) laboratoriju par viņu cirkonija oksīda ražotāju, pārliecinieties, vai viņi iegādājas cirkoniju no vadošajiem ražotājiem (piem., Kuraray Noritake Dental Inc.), izmantojot pilnvarotus izplatītājus vai pārdevējus, kurus viņi pazīst.
• Izvairieties no piedāvājumiem, kas ir pārāk labi, lai būtu patiesi: zemas cenas var būt vilinošas, taču ārstēšanas galīgās izmaksas var būt pat augstākas nekā parasti, ja rodas komplikācijas.

Ilgtermiņa ietekme pacientiem, izmantojot sertificētas cirkonija restaurācijas

Pārliecība, ka jūsu zobārstniecības kabinetā izmantotais cirkonijs atbilst augstākajiem iespējamajiem kvalitātes standartiem, ir svarīgs ieguldījums pacientu ilgtermiņa apmierinātībā. Pat ja augstas kvalitātes cirkonija restaurācijas sākotnējās izmaksas ir nedaudz augstākas nekā zemākas kvalitātes darba izmaksas, kopējais ieguldījums var būt mazāks, ja restaurācija kalpo ilgāk un tiek novērsta pārtaisīšana. Jūsu apmierinātie pacienti, visticamāk, būs vairāk iesaistīti un ievēros mutes higiēnu, kā arī būs lojāli, tādējādi pozitīvi ietekmējot jūsu reputāciju un pacientu bāzi.

Izpētiet cirkonija iespējas un izvēlieties produktus no sertificētiem ražotājiem

Ja vēlaties spert soli tālāk, varat pat salīdzināt vairāku ražotāju sertificētos cirkonija variantus un atklāt atšķirības. Piemēram, Kuraray Noritake Dental Inc. ir viens no nedaudzajiem zobu cirkonija mražotājiem, kas veic visu ražošanas procesu, tostarp izejvielu ražošanu uz vietas. Tādā veidā uzņēmums spēj kontrolēt katru procedūras soli un nodrošināt izcilu produkta kvalitāti – neatkarīgi no tā, kurš materiāla variants tiek izvēlēts. Ar pieejamo sortimentu, kas sastāv no KATANA™ Zirconia UTML (īpaši caurspīdīgs daudzslāņu), KATANA™ Zirconia STML (izcili caurspīdīgs daudzslāņu) un ļoti caurspīdīga daudzslāņu HTML PLUS, kā arī YML (ar papildu stiprības un caurspīdīguma gradāciju), ir iespējams aptvert praktiski visas indikācijas.

PROF. LORENCO BREŠI (LORENZO BRESCHI) RAKSTS

Mazāk pudeļu, vairāk izvēles – tas, iespējams, ir īsākais veids, kā aprakstīt universālo sveķu cementu kategoriju. Šie divkāršās cietēšanas sveķu cementi, kas ir pašlīmējoši, nodrošina vienkomponenta darbplūsmu, daudzās klīniskās situācijās neizmantojot atsevišķus zobu vai restaurācijas praimerus. Šādā veidā iegūtā saķeres stiprība parasti ir pietiekami augsta, lai nodrošinātu stabilu saķeri starp zobu un restaurāciju plašā indikāciju diapazonā. Tomēr tā ir nedaudz zemāka nekā tā, kas tiek sasniegta ar parastajām sveķu cementa sistēmām, kas sastāv no vairākiem komponentiem (parasti zobu saite sveķu cements un restaurācijas saite).

Papildus pašlīmējošajam uzklāšanas veidam universālos sveķu cementus var kombinēt ar papildu sistēmas sastāvdaļām, lai attiecīgi palielinātu saķeres stiprību ar zoba struktūru vai restaurācijas materiālu. Tas paver jaunas iespējas produkta lietošanā: atkarībā no nepieciešamās vai vēlamās saķeres veiktspējas universālo sveķu cementu var uzklāt atsevišķi vai kombinācijā ar zobu saiti restaurācijas saiti vai abām sastāvdaļām. Turklāt hibrīda koncepcijas kļūst iespējamas, kā paskaidrots šajā rakstā, kurā galvenā uzmanība pievērsta PANAVIA™ SA Cement Universal (Kuraray Noritake Dental Inc.) kā piemēram.

Pašcementējošā fiksācija: daudzām indikācijām

PANAVIA™ SA Cement Universal ir divējādi cietējošs universāls sveķu cements, kas ir paredzēts plašam pielietojumu klāstam, ja to izmanto pašcementējošā veidā. Saķere, kas izveidota ar restaurācijas substrātiem (tostarp silikāta keramiku), ir spēcīga, neizmantojot atsevišķu saiti vai silānu1-4. Tas ir saistīts ar diviem dažādiem lipīgajiem monomēriem, ko satur preparāts – oriģinālais MDP monomērs un LCSi monomērs (garas oglekļa ķēdes silāna savienošanas līdzeklis, kas atbild par spēcīgu ķīmisko saiti ar silikāta keramiku). Tādējādi ir iespējams izmantot sveķu cementu bez papildu komponentiem, kas tiek uzklāti uz restaurācijas sāniem – pat gadījumos, kad trūkst saķeres un līdz ar to ir augstas prasības attiecībā uz saķeres stiprību.

Spēcīga saķere ar emalju un dentīnu tiek iegūta arī pašlīmējošā veidā. Tomēr dažās situācijās var būt lietderīgi vēl vairāk palielināt saķeres stiprību ar zoba struktūru, izmantojot zobu saiti.

Adhezīva līmēšana: sarežģītām situācijām

PANAVIA™ SA Cement Universal ieteicamā zobu saite ir CLEARFIL™ Universal Bond Quick (Kuraray Noritake Dental Inc.). Tā lietošana ir ieteicama ikreiz, kad lietotājs uzskata, ka ārstēšanai noderētu īpaši spēcīga un izturīga ķīmiskā saite, t.i., īpaši sarežģītās situācijās ar nepietiekamu mehānisko noturību. Šī pasākuma efektivitāte ir apstiprināta Japānā veiktā in vitro pētījumā, kurā 24 stundu mikro stiepes saites stiprība pret dentīnu tika ievērojami palielināta, uzklājot universālo cementu5. Izmantojot atsevišķu cementu pieaug pilnīgi sausa darba lauka nozīme. Iemesls ir tāds, ka sveķu cementa mitruma tolerance parasti ir augstāka nekā cementiem. Līdz ar to koferdama uzlikšana ir ļoti ieteicama.

Selektīva adhezīva cementēšana: īsiem noslīpētiem zobiem un subgingivālajām malām

Situācijās, kad ir grūti pareizi izolēt darba lauku ar koferdamu ir pieejama trešā uzklāšanas iespēja, ko piedāvā Itālijas pētnieku grupa: selektīva adhezīva fi ksācija. Šajā gadījumā CLEARFIL™ Universal Bond Quick tiek uzklāts tikai uz tām sagatavotā zoba daļām, kas nodrošina pareizu mitruma kontroli, vienlaikus paļaujoties uz PANAVIA™ SA Cement Universal pašcementējošo funkcionalitāti vietās, kur ir grūti iegūt vēlamo sauso darba lauku. Situācijas, kas ir paredzētas šai tehnikai, ir slīpēti zobi ar subgingivālu sagatavošanu un īpaši īsi slīpēti zobi (kas kavē koferdama novietošanu).

Selektīvās adhezīva fiksācijas tehnikas efektivitāte ir pārbaudīta in vitro pētījumā, kurā tika salīdzinātas trīs līmēšanas stratēģijas – pašcementējošā fiksācija pilnībā adhezīva fiksācija un selektīva adhezīva fiksācija – ar bīdes saišu stiprības pārbaudes palīdzību6. Pārbaužu rezultāti liecina, ka lietotāji var uzlabot PANAVIA™ SA Cement Universal saķeres stiprību ar dentīnu un emalju, uzklājot cementu tikai uz zoba virsmas daļas. Cementēšanas sistēmai, kas sastāv no PANAVIA™ SA Cement Universal un CLEARFIL™ Universal Bond Quick, pilnībā adhezīva un selektīvā adhezīva pieeja radīja līdzīgus rezultātus.

Situācij ās, kad ir grūti pareizi izolēt darba lauku ar koferdamu ir pieejama trešā uzklāšanas metode ko piedāvā Itālij as pētnieku grupa: selektīva adhezīva fiksācija

Rekomendētās darbības selektīvajai adhezīva līmēšanai

1. attēls. Zoba sagatavošana

2. attēls. Selektiva emaljas kodinašana ar fosforskabes kodinataju

3. attēls. Universala adheziva uzklašana un žavešana ar gaisu

4. attēls. Krona novietošana pec sveku cementa uzklašanas kroni

5. attēls. Cietinašana

6. attēls. Lieka daudzuma noemšana un galeja cietinašana
gaisma

7. attēls. Arstešanas rezultats pec viena gada

Selektīvās adhezīva cementēšanas priekšrocības

Papildus vēlamajam (ilgtermiņa) saķeres stiprības pieaugumam, kas tiek panākts, uzklājot atsevišķu cementu uz daļas vai visas sagatavotās zoba virsmas, tehnika piedāvā papildu priekšrocības. Salīdzinot ar daudzpakāpju cementēšanas sistēmām, protokols ir vienkāršots, jo nav nepieciešams atsevišķa restaurācijas saite. Cementa cietināšana gaismā nav nepieciešama, kamēr lietotājs paliek ieteiktajā sistēmā. Un atšķirībā no pilnībā adhezīvas pieejas, kurā ir nepieciešams uzstādīt koferdamu šī soļa nepieciešamība ir izslēgta, izmantojot selektīvo adhezīva pieeju. Tādā veidā tiek samazināts krēslā pavadītais laiks un palielināts pacienta komforts.

Secinājumi

Atkarībā no indikācijas, klīniskajiem mainīgajiem lielumiem un individuālajām vēlmēm, universālo sveķu cementa, piemēram, PANAVIA™ SA Cement Universal, lietotāji var izvēlēties tehniku, kas, visticamāk, nodrošinās vislabākos klīniskos rezultātus. Tieši šī elastība un kopumā plašais pielietojumu klāsts padara inovatīvo produktu kategoriju patiesi universālu. Tā kā izmantojamo komponentu skaits ir mazāks, universālie materiāli atvieglo klīnisko procedūru racionalizāciju un standartizāciju, savukārt ar mazāku uzglabājamo pudeļu skaitu tas palīdz darbiniekiem iegūt kontroli pār pasūtījumu un uzglabāšanas pārvaldību.

Dentist:

LORENZO BRESCHI

Prof. Lorenzo Breschi ir restauraciju un zobarstniecibas materialu profesors Bolonas Universitate. Vinš aktivi iesaistas emaljas un dentina ultrastrukturalo
aspektu petijumos. Vinš ir bijušais Zobarstniecibas materialu akademijas (ADM) prezidents, Eiropas Konservativas zobarstniecibas federacijas (EFCD) ieveletais prezidents, Zobarstniecibas materialu grupas IADR ieveletais prezidents, Italijas Konservativas zobarstniecibas akademijas (AIC) ieveletais prezidents, Starptautiskas adhezivas zobarstniecibas akademijas (IAAD) ieveletais prezidents.

Atsauces

1. Cowen M, Cunha S, Powers JM. Novel Cement Bond Strength to Multiple Substrates.
DENTAL ADVISOR Biomaterials Research Center, Biomaterials Research Report, Number
132 - June 16, 2020. 2. Patel N, Anadioti E, Conejo J, Ozer F, Mante F, Blatz M. Bond
Strength of Different Self-Adhesive Resin Cements to Zirconia” (2021). Dental Theses.
62. https://repository.upenn.edu/dental_theses/62 3. Yoshihara K, Nagaoka N, Maruo Y,
Nishigawa G, Yoshida Y, Van Meerbeek B. Silane-coupling effect of a silane-containing
self-adhesive composite cement. Dent Mater. 2020 Jul;36(7):914-926. 4. Irie M, Tokunaga
E, Maruo Y, Nishigawa G, Yoshihara K, Nagaoka N, Minagi S, Matsumoto T. Shear bond
strength of a resin cement to CAD/CAM Blocks for molars. P-2, 37th Annual Meeting of the
Japanese Society of Adhesive Dentistry 2018. 5. Ohara N. Bonding strength of resin cement
containing silane coupling agent to dentin or core resin. Results presented at the 150th
meeting of the Japanese Society of Conservative Dentistry. 6. Breschi L, Josic U, Maravic
T, et al. Selective adhesive luting: A novel technique for improving adhesion achieved by
universal resin cements. J Esthet Restor Dent. 2023;1-9. doi:10.1111/jerd.13037

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.

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

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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.
   
   
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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

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Case by Dr. Jusuf Lukarcanin

Abrasion and shape correction was also the major reason for this 58-year-old female patient to ask for cosmetic dental treatment. She was unhappy with the appearance of the anterior teeth in the maxilla, which showed signs of tooth wear and discolouration. The selected treatment approach was composite veneering with CLEARFIL MAJESTY™ ES-2 Universal in the shade UD. The shade was selected based on the indication and the somewhat darker shade of the patient’s natural teeth.

Fig. 1. Initial clinical situation.

Fig. 2. Treatment outcome.

Reasons for selecting universal dark:

- For older patients (tooth shades A3 and darker)

- Situations in which light easily passes through the composite (e.g., Class III, Class IV)

Universal dark properties:

- High light scattering effect

- Well-balanced translucency