No Author Selected

PRESENTATION OF A STUDY WITH ILLUSTRATIVE CASES

by Dr. Yohei Sato, DMD, PhD and Dr. Keisuke Ihara, CDT.

INTRODUCTION

In recent years, the application and advancement of digital technology in dentistry has made it possible to accomplish the fabrication of highly accurate prosthetic zirconia appliances that were difficult to mill using the previously available technology. In addition, thanks to advances in adhesive dentistry and the advent of cements that bond strongly to a diverse range of materials, cements have come into wide clinical use that can cope with the many types of materials used for the fabrication of prosthetic appliances.

At our hospital, we select the treatment method most suitable for each case by appropriately specifying various types of prosthetic appliance according to the status of each case. For example, we may specify zirconia prosthetic restorations fabricated by the CAD/CAM system, or silica-based ceramic prostheses, or those made of lithium disilicate glass, as the case dictates.

PANAVIA™ V5 is a resin cement system that bonds strongly to various types of prosthetic appliance, as well as to tooth structure. PANAVIA™ Veneer LC, a new resin cement system developed by Kuraray Noritake Dental Inc., has suitable characteristics for bonding laminate veneers, using two types of primer that can be used in common with PANAVIA™ V5. Here are some clinical examples of its advantages as a resin cement system used for laminate veneers restorations.

INOVATĪVA CIETĒŠANAS TEHNOLOĢIJA
PANAVIA™ Veneer LC nodrošina gaismā cietējošu cementu, apvienojot vairākas tehnoloģijas, nodrošinot augstāko iespējamo adhēziju.

VIRSMAS HERMETIZĀCIJA
Modificētā skāriencietināšanas tehnoloģija tiek izmantota, lai sasniegtu ilgāku apstrādes laiku, vienlaikus nodrošinot PANAVIA™ izslavēto adhēziju. PANAVIA™ Veneer LC, apvienojumā ar PANAVIA™ V5 Tooth Primer nodrošina gaismā cietējošajam cementam būtisku ķīmisko elementu. PANAVIA™ V5 Tooth Primer ir paškodinošs zoba audu (emaljas un dentīna) praimeris kas droši hermetizē zoba adhezīvo virsmu, kolīdz tas saskaras ar PANAVIA™ Veneer LC Paste. Vieglais, skāriencietējošais praimeris aktivizē tikai adhezīvās virsmas polimerizāciju un rada tūlītēju, noturīgu sasaisti ar emalju un dentīnu, taču neietekmē cementa cietēšanu un tādējādi - arī apstrādes laiku.

APSTRĀDES LAIKS
Cementēšanas procedūru laikā apstrādes laiku būtiski ietekmē vairāki ārējie faktori. PANAVIA™ Veneer LC tehnoloģijā šie faktori ir ņemti vērā.
Skāriencietināšanas tehnoloģija ļauj nekavējoties hermetizēt zoba saskarsmes virsmu, kas ir augstās adhēzijas noturības pamatā. Cementa
cietēšanas tehnoloģija nodrošina 200 sekunžu apstrādes laiku apkārtējā gaismā* pirms PVLC zaudē teicamo veidošanas elastību. Šo 200
sekunžu laikā varat ērti novietot un koriģēt (vairākus) venīrus. Gala polimerizācija notiek tad, kad tiek veikta gaismošana ar cietināšanas
lampu.
*Apkārtējā gaisma: aptuveni 8000 lux

JAUNAS PILDVIELAS
PANAVIA™ Veneer LC teicamo apstrādi sekmē nesen izstrādātās lodveida silīcija pildvielas un nanoklāsteru pildvielas (pildvielas noslodze: 66 wt%, 47 vol%). Cementa tiksotropisko īpašību dēļ nenotiek sēšanās vai nobīde. PANAVIA™ Veneer LC nodrošina kontrolētu uzklāšanu, cements paliek uzklāšanas vietā, taču labi plūst venīra(-u) novietošanas laikā.
Cementa viendabīguma un kārtas plānuma (≈ 8 μm) dēļ PANAVIA™ Veneer LC nodrošina plānu, vienmērīgu cementa slāni. Tādējādi tiek sekmēta viegla nosēdināšana bez traucējumiem. Līdztekus tam, tiek lietotas tikai nelielas, lodveida pildvielas (daļiņu izmērs: 0,05 μm – 8 μm), kas nodrošina īpaši estētiskas un gludas piemales, kā arī sekmē pulēšanu un spīduma noturību.

SILĪCIJA PILDVIELAS
Nesen izstrādātās cementa lodveida silīcija pildvielas nodrošina, ka cements paliek uzklāšanas vietā, taču labi plūst venīra nosēdināšanas laikā. Nodrošina vieglu uzlikšanu bez nobīdes vai sēšanās. Veicot uzklāšanu uz restaurācijas, sveķu cements nelīp pie uzklāšanas uzgaļa - šī īpašība tiek panākta, pastai pievienojot nanoklāsteru pildvielas.

Jaunie pildvielu veidi rada
teicamu gludumu, spīduma
noturību, kā arī vienkāršu
apstrādi.

VISKOZITĀTE UN TIKSOTROPIJA
Cementa viskozitāte ir būtiska, un tai jābūt pietiekamai zemai, lai novērstu restaurācijas plaisāšanu novietošanas laikā. Vienlaikus cements nedrīkst būt tikt plūstošs, lai tas notecētu uzklāšanas laikā un sēstos apstrādes laikā. Tā kā PANAVIA™ Veneer LC satur optimizētu pildvielas/sveķu maisījumu, tā viskozitāte mainās atkarībā no spiediena. Šo fenomenu dēvē par tiksotropiju. Pasta kļūst plūstošāka zem spiediena venīra novietošanas un koriģēšanas laikā. Spiedienam mazinoties, viskozitāte atjaunojas. PANAVIA™ Veneer LC tiksotropisko īpašību dēļ pastu var viegli izkliedēt un restaurācijas novietošanai ir vajadzīgs neliels spiediens, turklāt lieko materiālu ir viegli noņemt. Īsāk sakot: maksimāla kontrole.

Case by Dr. Aleksandra Łyżwińska, Warsaw, Poland

ABSTRACT

Indirect overlays are the contemporary restoration standard for posterior teeth with extensive hard tissue loss. They provide for cuspal coverage, which decreases the likeliness of coronal and/or root fracture. At the same time and in contrast to crowns, overlay preparations minimize the removal of sound tooth structure especially in the cervical region, which is a critical factor.¹ Modern dental resin composites allow for direct cuspal coverage in a single-visit appointment. The results of in-vitro studies suggest that these direct overlays are a suitable alternative to their indirect counterparts in specific situations.^2-6 The following case report is used to describe the direct restoration procedure by means of a maxillary right molar with an extensive, deep MOD lesion.

INTRODUCTION

In the context of treating a tooth with an extensive carious lesion, a biomechanical risk assessment should be performed. The primary method of reducing the likeliness of tooth fracture is treatment with a restoration that provides cuspal coverage. The contemporary gold standard for biomechanically compromised teeth are adhesively cemented overlays as an alternative to crowns.¹ Another option that does not involve labwork is a direct overlay restoration.^2-6 The direct approach is especially suitable for long-term temporization, which may be required during orthodontic treatment, for example.

CLINICAL CASE

The 40-year-old male patient was referred to my office before an orthodontic and prosthetic treatment. Intraoral examination (Figs. 1 and 2) revealed:

• Tetracycline discolouration,
• Multiple extensive composite restorations with marginal leakage,
• Primary and secondary carious lesions, and
• Significant mechanical weakness^7,8 (mesio-occluso-distal (MOD) cavities, cusp loss, cracks).

Fig. 1. Initial situation – extensive MOD composite resin restoration.

Fig. 2. Initial situation – unacceptable contact points, palatal wall crack line.

Based on a clinical and radiological examination (Fig. 3), it was decided to restore the maxillary right first molar with a direct overlay, which should serve as a long-term temporary for the duration of orthodontic treatment. Once the local anaesthetic had been administered, rubber dam was placed in the first quadrant and the cusps of the affected first molar were reduced. For subgingival tooth preparation, a rubber dam sheet was temporarily moved behind the second upper molar (Fig. 4). In order to obtain a good emergence profile of the restoration and a tight fit of the sectional matrix, the gingivectomy was performed with an electric surgical knife (Surtron 50D, LED SPA) (Fig. 5). The main advantages of a diathermal cut are instant tissue coagulation and hemostasis⁹.

Fig. 3. Bite-wing radiograph: Maxillary fist molar with an overhang and negative profile of the distal wall.

Fig. 4. Initial preparation with reduction of the cusps and exposure of gingiva.

Fig. 5. Gingivectomy performed using a surgical electric knife.

In accordance with the European Society of Endodontology’s guidelines on the management of deep caries¹⁰, the deepest part of the cavity was cleaned in full rubber dam isolation (Nic Tone Dental Dam, MDC Dental) (Fig. 6). Carious-tissue excavation was carried out using round burs, then the enamel and dentin were air-abraded with 50-μm aluminum oxide (Microetcher IIa, Danville). Multiple cracks, penetrating through the enamel and partially the dentin, occurred within the mesial and palatal walls. The presence of cracks crossing the dentin-enamel junction is an absolute indication to cuspal coverage^8,11.

An appropriate rubber dam isolation is essential in adhesive dentistry. Beyond the obvious advantage of a clean operation field uncontaminated by saliva and moisture, the rubber dam contributes to keeping periodontal tissues at a distance form a tooth. In order to ensure both, maximum retraction and sufficient space to work, the rubber dam was inverted (introduced to the gingival sulcus) and stabilized using PTFE tape (Fig. 7). The mesial wall was restored using a blue 3D Composite-Tight 3D Fusion matrix ring (Garrison) and a medium standard Sectional Contoured Metal Matrix (TOR VM, Fig. 8). Due to its extensiveness and shape, restoration of the distal wall was more difficult to perform.

Fig. 6. Rubber dam newly placed in the interproximal area. Full isolation is essential for the excavation of the infected dentin in the deepest part of the cavity.

Fig. 7. PTFE tape placement for improving isolation in the gingival area. Al₂O₃ sandblasting.

Fig. 8. Mesial matrix fit.

The first attempt to adapt an elongated Sectional Contoured Metal Matrix and the green 3D Composite-Tight 3D Fusion (Garrison) ended with failure (Fig. 9). The matrix was changed for a longer and more curved one (Fig. 10). The ring was replaced by a smaller Palodent V3 Ring (Dentsply Sirona, Fig. 11). Due to the depth of the carious lesion, an antibacterial adhesive system was used (CLEARFIL™ SE Protect, Kuraray Noritake Dental Inc.). It contains the MDPB monomer, which offers an antibacterial effect that lasts even after hybrid layer formation^12-14. Furthermore, the fluoride included in the bond liquid intensifies the cariostatic mechanism of CLEARFIL™ SE Protect and supports the so-called “Super Dentin” formation¹⁵.

Fig. 9. Insufficient fit of the distal matrix.

Fig. 10. New, longer and more curved matrix in place.

Fig. 11. Different matrix ring placed in the distal area.

After polymerization of the bonding agent, the nanohybrid flowable composite resin (CLEARFIL MAJESTY™ ES Flow High, Kuraray Noritake Dental Inc.) was applied in a thin layer. The proximal wall was restored using both packable (CLEARFIL MAJESTY™ ES-2 Universal, Kuraray Noritake Dental Inc.) and flowable composite resin (CLEARFIL MAJESTY™ ES Flow Super Low, Kuraray Noritake Dental Inc.) (Figs. 12 and 13). Core build-up was performed with bulk-fill type composite. The cusps were reconstructed free-hand with the previously used CLEARFIL MAJESTY™ ES-2 Universal (Figs. 14 and 15). The universality of this product provides for a good optical integration and blending with the adjusted tissue, regardless of the colour of the underlying tooth structure. The fissures were gently highlighted using brown tints.

Fig. 12. Thin layer of flowable composite resin CLEARFIL MAJESTY™ ES Flow High (A2) applied on the cavity floor. The proximal walls are built up with build-up by CLEARFIL MAJESTY™ ES-2 Universal and CLEARFIL MAJESTY™ ES Flow Super Low (A2).

Fig. 13. Proximal walls build-up – palatal view.

Fig. 14. Core build-up. Free-hand cusp coverage with CLEARFIL MAJESTY™ ES-2 Universal, palatal view.

Fig. 15. Cusp coverage – occlusal view.

The initial polishing was performed with the rubber dam still in place. The excesses of composite resin were removed with the aid of abrasive discs, diamond burs and a “Brownie” polisher (BAL, Nevadent). Pre-polishing and high-shine polishing were executed with TWIST™ DIA for Composite (Kuraray Europe GmbH.) supported by a goat hair brush (Micerium) (Figs. 16 to 17).

Fig. 16. Occlusal surface after surface modeling with CLEARFIL MAJESTY™ ES-2 Universal and initial polishing.

Fig. 17. Occlusal surface after modeling with CLEARFIL MAJESTY™ ES-2 Universal and initial polishing – palatal view.

After removal of the rubber dam, the occlusal contact points of the direct overlay were adjusted (Figs. 18 and 19). Every spot touched by the burr was subsequently repolished according to the previously described protocol (Figs. 20 and 21).

Fig. 18. Occlusal adjustment. Contact points recorded with articulation paper (100 μm).

Fig. 19. Occlusal adjustment. Contact points recorded with articulation paper (100 μm= and articulation foil (16 μm).

Fig. 20. Final effect after polishing with TWIST™ DIA for Composite.

FINAL SITUATION

Fig. 21. Final effect – palatal view.

CONCLUSION

As a result of decades of improvements mainly with regard to the filler density and polishability, modern dental composites offer a great gloss retention and favourable wear properties. In addition, polymerization shrinkage has been decreased due to the integration of nanohybrid filler technology. Those features allow us to restore biomechanically compromised teeth using a direct restoration technique.

Direct overlays are a suitable alternative for a conventional indirect restoration in many situations.^18,19 According to researchers, the advantages of direct restorations with cuspal coverage include minimal tooth preparation, vital pulp-oriented treatment, the possibility to treat patients in a single appointment and a potentially lower cost of the treatment.^18-20 However, it should be emphasized that the presented technique requires advanced restorative skills that need to be acquired first before starting to implement it.

Dentist:

DR. ALEKSANDRA ŁYŻWIŃSKA
Warsaw, Poland

Dr. Aleksandra Łyżwińska is a restorative dentist. She graduated from the Warsaw Medical University in 2017, where she was an assistant professor at the Department of Conservative Dentisyty and Endodontics. Her focus lies in modern adhesive techniques, resin composites and biomaterials.

REFERENCES

1. Dietschi D, Duc O, Krejci I, Sadan A. Biomechanical considerations for the restoration of endodontically treated teeth: a systematic review of the literature--Part 1. Composition and micro- and macrostructure alterations. Quintessence Int. 2007 Oct;38(9):733-43.
2. van Dijken JW. Direct resin composite inlays/onlays: an 11 year follow-up. J Dent. 2000 Jul;28(5):299-306. doi: 10.1016/s0300-5712(00)00010-5. PMID: 10785294.
3. Mondelli RF, Ishikiriama SK, de Oliveira Filho O, Mondelli J. Fracture resistance of weakened teeth restored with condensable resin with and without cusp coverage. J Appl Oral Sci. 2009 May-Jun;17(3):161-5.
4. Deliperi S, Bardwell DN. Multiple cuspal-coverage direct composite restorations: functional and esthetic guidelines. J Esthet Restor Dent. 2008;20(5):300-8; discussion 309-12.
5. Deliperi S, Bardwell DN. Clinical evaluation of direct cuspal coverage with posterior composite resin restorations. J Esthet Restor Dent. 2006;18(5):256-65; discussion 266-7.
6. Mincik J, Urban D, Timkova S, Urban R. Fracture Resistance of Endodontically Treated Maxillary Premolars Restored by Various Direct Filling Materials: An In Vitro Study. Int J Biomater. 2016;2016:9138945.
7. Reeh ES, Messer HH, Douglas WH. Reduction in tooth stiffness as a result of endodontic and restorative procedures. J Endod. 1989 Nov;15(11):512-6.
8. Banerji S, Mehta SB, Millar BJ. The management of cracked tooth syndrome in dental practice. Br Dent J. 2017 May 12;222(9):659-666.
9. Bashetty K, Nadig G, Kapoor S. Electrosurgery in aesthetic and restorative dentistry: A literature review and case reports. J Conserv Dent. 2009 Oct;12(4):139-44.
10. European Society of Endodontology (ESE) developed by:, Duncan HF, Galler KM, Tomson PL, Simon S, El-Karim I, Kundzina R, Krastl G, Dammaschke T, Fransson H, Markvart M, Zehnder M, Bjørndal L. European Society of Endodontology position statement: Management of deep caries and the exposed pulp. Int Endod J. 2019 Jul;52(7):923-934.
11. Lynch CD, McConnell RJ. The cracked tooth syndrome. J Can Dent Assoc. 2002 Sep;68(8):470-5.
12. Hashimoto M, Hirose N, Kitagawa H, Yamaguchi S, Imazato S. Improving the durability of resindentin bonds with an antibacterial monomer MDPB. Dent Mater J. 2018 Jul 29;37(4):620-627.
13. Imazato S, Kinomoto Y, Tarumi H, Torii M, Russell RR, McCabe JF. Incorporation of antibacterial monomer MDPB into dentin primer. J Dent Res. 1997 Mar;76(3):768-72.
14. Imazato S, Kinomoto Y, Tarumi H, Ebisu S, Tay FR. Antibacterial activity and bonding characteristics of an adhesive resin containing antibacterial monomer MDPB. Dent Mater. 2003 Jun;19(4):313-9.
15. Nakajima M, Okuda M, Ogata M, Pereira PN, Tagami J, Pashley DH. The durability of a fluoride-releasing resin adhesive system to dentin. Oper Dent. 2003 Mar-Apr;28(2):186-92.
16. Bore Gowda V, Sreenivasa Murthy BV, Hegde S, Venkataramanaswamy SD, Pai VS, Krishna R. Evaluation of Gingival Microleakage in Class II Composite Restorations with Different Lining Techniques: An In Vitro Study. Scientifica (Cairo). 2015;2015:896507.
17. Oficjalne informacje producenta Kuraray Noritake Dental https://www.kuraraynoritake.eu/pl/clearfil-majesty-es-flow (dostęp 08.02.2022).
18. Angeletaki F, Gkogkos A, Papazoglou E, Kloukos D. Direct versus indirect inlay/onlay composite restorations in posterior teeth. A systematic review and meta-analysis. J Dent. 2016 Oct;53:12-21.
19. Dhadwal AS, Hurst D. No difference in the long-term clinical performance of direct and indirect inlay/onlay composite restorations in posterior teeth. Evid Based Dent. 2017 Dec 22;18(4):121-122.
20. Banerji S, Mehta SB, Millar BJ. Cracked tooth syndrome. Part 2: restorative options for the management of cracked tooth syndrome. Br Dent J. 2010 Jun;208(11):503-14.
21. Opdam NJ, Roeters JJ, Loomans BA, Bronkhorst EM. Seven-year clinical evaluation of painful cracked teeth restored with a direct composite restoration. J Endod. 2008 Jul;34(7):808-11.
22. van Dijken JW. Direct resin composite inlays/onlays: an 11 year follow-up. J Dent. 2000 Jul;28(5):299-306.

The vacation period is over and we all are slowly returning back to our everyday routines and work. With all the travel and holidays in the last months you might have missed this great article in the LabLine Summer edition: Graftless solutions and implant-supported monolithic zirconia fixed prostheses.

It is an extensive, beautiful and detailed case report created and documented by team of well known and respected KOLs: Fortunato Alfonsi, Antonio Barone, Marco Stoppaccioli, Romeggio Stefano and Vincenzo Marchio.

Check it out by clicking here.

LAMINATE VENEER RESTORATION
USING LITHIUM DISILICATE

WITH PANAVIA™ Veneer LC (Clear)
Case by Yohei Sato (DMD, PhD) and Keisuke Ihara (CDT)

Fig. 1 The patient visited would like to have the a aesthetics
of the maxillary right and left lateral incisors improved.

Fig. 2 A silicon guide fabricated from a diagnostic wax model
was applied and the necessary clearances were determined.

Fig. 3 Since the lateral teeth are microdonts, the
preparation of each abutment was completed by simply
exposing a fresh enamel surface to be covered with
laminate veneers.

Fig. 4 A layer of porcelain was applied on the lithium
disilicate substrate, to complete the laminate veneers.

Fig. 5 The veneer was conditioned according to the
prosthesis‘ IFU. After trial fitting, the intaglio surface of the
laminate veneer was cleaned with KATANA™ Cleaner.

Fig. 6 CLEARFIL™ CERAMIC PRIMER PLUS was applied and
dried to prime the restoration.

Fig. 7 The preparation was cleaned with KATANA™ Cleaner.
Applied and rubbed for more than 10 seconds. Then, it
was washed off sufficiently (until the cleaner color had
completely disappeared), and dried with compressed air.

Fig. 8 K-ETCHANT Syringe was applied and left for 10
seconds before water-rinsing and compressed air-drying.

Fig. 9 PANAVIA™ V5 Tooth Primer was applied and left for 20
seconds before mild compressed-air drying.

Fig. 10 PANAVIA™ Veneer LC Paste was applied to the
intaglio surface of the laminate veneer.

Fig. 11 The laminate veneer was seated and the fit
checked. Then, the excess cement was tack-cured (not
more than 1 second at each point) and removed. Finally,
the restoration was light-cured and finished.

FINAL SITUATION

Fig. 12 The laminate veneer restorations one month after
placement. The morphology and color of the right and
left lateral incisors have been improved, providing a good
balance to the entire anterior dentition.

LAMINATE VENEER RESTORATION
USING KATANA™ Zirconia STML

WITH PANAVIA™ Veneer LC (Clear)
Case by Yohei Sato (DMD, PhD) and Keisuke Ihara (CDT)

Fig. 1 The patient was referred by an orthodontist. The main
complaints were improper aesthetics of the teeth due to dark
triangles betwen the teeth and incisal wear.

Fig. 2 On the basis of the pre-treatment diagnosis using
a mockup, the teeth were prepared, with keeping in mind
that the enamel should be preserved to the maximal extent
possible.

Fig. 3 A fixation retainer was present at the palatal side,
making it difficult to take coventional silicon impressions.
Therefore, an intraoral scanner was used.

Fig. 4 A layer of porcelain was applied to each KATANA™
Zirconia STML laminate veneer to complete the restorations.
The inner surface of each restoration was sandblasted, being
careful to prevent chipping.

Fig. 5 After trial fitting, bonding inhibiting substances as
blood and saliva were removed using KATANA™ Cleaner.

Fig. 6 CLEARFIL™ CERAMIC PRIMER PLUS was applied and
dried using compressed air.

Fig. 7 The surface of each tooth was cleaned and treated
with K-ETCHANT Syringe for 10 seconds before washing it
away with water and drying with compressed air.

Fig. 8 PANAVIA™ V5 Tooth Primer was applied and left f

Fig. 9 PANAVIA™ Veneer LC Paste was applied and the
laminate veneers were seated. For this case, we placed six
veneers during one session.

Fig. 10 The unpolymerized excess paste was removed with
a brush according to the wet clean-up technique.

Fig. 11 The result after final light curing. Since the excess
cement was easily removed, there were almost no cement
residues.

FINAL SITUATION

Fig. 12 Result one month after placement of the laminate
veneer restorations. The marginal gingiva has been improved
thanks to the good fit of the laminate veneer restorations.

Prosthodontic treatment concepts have evolved over the past decades. While some time ago, porcelain-fused-to-metal crowns and bridges were placed wherever a defect was too large for a direct restoration, the current trend is toward less invasive therapies with highly aesthetic, tooth-coloured materials.

These modern treatment concepts can lead to reliable outcomes when a high-performance resin cement system is used that establishes a durably strong bond to tooth structure on one side and the restoration on the other. The reason is that less invasive often means that restorations have minimal or no retentive elements and extremely thin walls, and a strong chemical bond is a mechanism that holds them in place over time. Depending on the type of restoration and area in the mouth, aesthetic properties of the cementation system are also extremely important, as the typically highly translucent, thin restorations tend to reveal the appearance of the structures underneath to a certain extent.

Universal cements

In the context of striving toward the streamlining of clinical procedures in restorative dentistry, several manufacturers have developed resins cements that work with fewer components and are suitable for a large number of indications. PANAVIA™ SA Cement Universal is a popular example. The self-adhesive, dual-cure resin cement is the only product of its category that works as a standalone solution even on glass ceramics (without the need for a separate primer).

The need for specialists

There are specific clinical situations, however, that require more working time than a dual-cure resin cement can offer. This is the case whenever multiple non-retentive restorations are to be placed simultaneously, a technique that is recommended for veneers. The greatest benefits of placing the thin and highly aesthetic restorations at once lie in the proper positioning of the restorations and in the minimized risk of contamination: When the veneers are placed one after the other, a slightly malpositioned and already fixed veneer might hinder proper positioning of the adjacent restorations and haemorrhage occurring in the context of excess cement removal or finishing of the margin might contaminate the working field. When all veneers are placed simultaneously, repositioning is possible, while excess removal and polishing are accomplished in a moment when blood and debris will no longer endanger the integrity of the restorations, which increases the security during the whole procedure. This task is best fulfilled by a light-curing veneer specialist.

Handling of a thin ceramic veneer.

Required properties of veneers cements

Undoubtedly, the key feature of a specialist resin cement system is a long working time sufficient for simultaneous cementation of multiple restorations. In addition, its consistency and handling properties are also important as they can help users overcome the challenge of accurate positioning and reduce the time and effort involved in veneer placement. And finally, the system needs to provide excellent bond strength over time and support long-lasting aesthetics, properties valuable for every kind of resin cement, but the latter being particularly important for thin restorations in the aesthetic zone. Luckily, PANAVIA™ Veneer LC offers all those features.

The system consists of PANAVIA™ V5 Tooth Primer that establishes a strong bond to enamel and dentin, PANAVIA™ Veneer LC Paste as the cement and the CLEARFIL™ CERAMIC PRIMER PLUS that has been part of PANAVIA™ V5 cementation system. The latter is responsible for a high bond strength to all types of restorative materials.

Mastering the working time challenge

The light-curing cement paste offers a long working time of 200 seconds* due to its excellent stability under ambient light. As a consequence, dental practitioners may place multiple veneers simultaneously without having to race against setting. Polymerization may be started whenever the user is ready for it. The one-component self-etching tooth primer (PANAVIA™ V5 Tooth Primer) does not contain any photo initiators and does not cure alone. When applied, it etches and penetrates into the tooth surface for 20 seconds and is ready to bond strongly to PANAVIA™ Veneer LC Paste. The integrated touch-cure technology is the key feature safeguarding a high bond strength to tooth structure without shortening the working time.

*Working time under ambient light on PANAVIA™ V5 Tooth Primer (8000 Lux): 200 seconds

Providing for precise placement

In order to streamline the clinical seating procedure from cement application to polishing, PANAVIA™ Veneer LC has been equipped with a set of well-balanced handling properties. Newly developed spherical silica fillers in the cement provide that it stays put where applied, but flows well when the veneer is seated on the tooth – for easy placement without drifting or sagging. During application across the intaglio surface, the resin cement does not stick to the application tip, a property achieved by the addition of nanocluster filler technology. The special design of the syringe’s application tip optimizes control over the amount of cement applied. Ans last but not least, excess cement may be easily removed in one piece using an explorer after a one-second tack-cure, while polishing of the margins is quickly accomplished.

Hiding the margins

Being extremely thin, highly translucent and mainly used to restore teeth in the exposed anterior region of the maxilla, veneers have to be placed with a cement that is and remains undetectable underneath the restoration and at its margins. PANAVIA™ Veneer LC is available in four highly aesthetic shades with matching try-in pastes, so that a precise shade match with the restoration can be achieved and verified in the patient’s mouth. Additional features contributing to undetectable margins are the resin cement’s flowability and low film thickness: They enable users to easily produce an evenly distributed, thin cement layer for aesthetic outcomes. For those afraid that coffee, tea, acidic drinks or constant tooth brushing might reveal the margins over time, there is good news as well: PANAVIA™ Veneer LC offers a high polish retention and colour stability over time. The well-balanced formulation and the touch-cure technology are responsible for this resistance to discolouration.

Trusted expertise

All these beneficial features make PANAVIA™ Veneer LC worth testing. Additional arguments are the fact that its primers are tried and tested components of the highly popular PANAVIA™ V5 system and that Kuraray Noritake Dental Inc. is a proven expert on adhesive products. It developed the original MDP Monomer in 1981 and introduced the first adhesive resin cement containing this monomer in 1983. Since then, the company has improved existing formulations and developed existing technologies that ultimately resulted in the current line-up of cementation solutions for every need and indication.

Excellent gloss retention is one of the properties providing for undetectable margins over time.

Kuraray Noritake Dental’s reputation as a pioneer in the field of dental adhesives is grounded in its development of the MDP monomer. Patented in 1981, the monomer was used two years later in the composite cement PANAVIA™ EX and has since formed the backbone of many other successful products. Now, the company has combined the original MDP monomer with hydrophilic amide monomers to create rapid bond technology that powers CLEARFIL™ Universal Bond Quick - a universal solution emblematic of Kuraray Noritake Dental’s history of success and commitment to innovation.

Advances in modern dental bonding technology have resulted in a reduction in the number of components needed for total-etching and self-etching processes. However, the basic handling of these adhesives has, by and large, changed surprisingly little. Many adhesives require a shaking of the bottle before usage, extensive rubbing of the liquid and/or waiting for a period of time. Often the application of multiple layers is needed. A reliance on slow penetrating monomers means that, for traditional one-bottle adhesives, bonding to the challenging dentine substrate is a slow and technique-sensitive process.

Through the integration of newly developed amide monomers, rapid bond technology provides CLEARFIL™ Universal Bond Quick with excellent hydrophilic properties and the ability to penetrate the wet dentine fast and effectively. There is no need to wait after the application for air-drying before proceeding - this delay has been eliminated - and a tight and long-lasting seal of the cavity is established after light-curing. Bonding with CLEARFIL™ Universal Bond Quick is easy and efficient and comes with predictable clinical outcomes, thanks to rapid bond technology.

Impressively low water sorption

One of the most important indicators of long-term success in dentine bonding is the level of water sorption in the bond’s organic matrix. A high rate of water sorption has been clinically linked to the ongoing physical deterioration of bonds, which may lead to the development of secondary caries. For this reason, we have chosen to keep the HEMA content as low as possible.

CLEARFIL™ Universal Bond Quick creates a highly cross-linked polymer network owing to the amide monomers used in rapid bond technology. As a result, it demonstrates a relatively low rate of water sorption, meaning that these cross-linked polymers are more stable in the long term.

Aesthetic, effective bonds

Rapid bond technology does not just provide a basis for long-lasting bonding excellence. The thin film layer (5–10 μm) of CLEARFIL™ Universal Bond Quick delivers restorations a clear aesthetic appeal, and its densely cross-linked polymer network reinforces the stability of this outer layer and provides resistance to marginal discoloration.

By combining Kuraray Noritake Dental’s original MDP monomer with hydrophilic amide monomers, rapid bond technology is truly the engine that powers CLEARFIL™ Universal Bond Quick.

By Franklin Tay, BDSc (Hons), PhD

STATE-OF-THE-ART CURRENT ADHESIVES

Manufacturers have adopted an etch-and-rinse approach or a self-etch approach in the design of adhesives for bonding restorative materials to tooth structures, which differ in how these adhesives interact with dental hard tissues. Etch-and-rinse adhesives are offered as two- or three-step systems, depending on whether primer and bonding are separate or combined in a single bottle. Likewise, self-etch adhesives are available as one- or two-step systems. Etch-and-rinse adhesives are often preferred when large areas of enamel are still present, while self-etch adhesives provide more predictable bonds to dentin.

Despite current trends toward fewer and simpler application steps, one-step adhesive systems appear to be less predictable than multi-step etch-and-rinse and self-etch systems. Some manufacturers have recently introduced more versatile single-bottle “universal” or “multi-mode” adhesives that encompass self-etch chemistry but also enable the same adhesive to be used with phosphoric acid-etching in the etch-and-rinse mode. Some universal adhesives also incorporate silane primer for chemical bonding to silica-based ceramics, and methacryloyloxydecyl dihydrogen phosphate (MDP) for chemical bonding to zirconia-based ceramics. Because clinical studies on universal adhesives are short-term, they cannot be considered state-of-the-art in the context of evidence-based dentistry. Conversely, two-step mild, self- etch adhesives have been well-tested in clinical trials and represent the current state-of-the-art for bonding to dentin, with reduced incidence of postoperative sensitivity when compared to etch-and rinse adhesives.

DEVELOPMENT OF CONTEMPORARY ADHESIVES FROM A RESEARCHER’S PERSPECTIVE

The current thinking by researchers is that dentin bonding is not as durable as it was originally perceived. This lack of durability is attributed partially to secondary caries around restorative margins that are devoid of enamel and partially to the degradation of the adhesive joint. The latter may be caused by the hydrolysis of ester bonds in the adhesive component by salivary esterases, or by degradation of water-rich, resin-sparse regions of the hybrid layers by endogenous collagen-bound proteases such as matrix metalloproteinases (MMP) and cathepsin K, that are activated from their dormant preforms to active forms by the acidity of contemporary adhesives. These activated enzymes slowly degrade the denuded collagen matrix within hybrid layers, resulting in gradual loss of adhesion.

Much work has been done in developing therapeutic dental adhesives that are able to resist secondary caries and degradation of the adhesive joint. One of the most thoroughly studied antimicrobial resin monomers is the quaternary ammonium methacrylate developed by Kuraray known as methacryloyloxydodec ylpyridinium bromide (MDPB). This polymerizable resin monomer is incorporated in the two-step self-etch adhesive CLEARFIL™ SE Protect. Recent research has demonstrated that MDPB resin is also an effective inhibitor of both MMP and cysteine cathepsins, thereby providing a mechanism to increase the longevity of resin–dentin bonds by preventing collagen degradation. Indeed, an in-vitro and in-vivo study (Donmez, et al. J Dent Res. 2005;84:355-359) showed that resin-dentin bonds created with CLEARFIL™ SE Protect (aka, CLEARFIL™ Protect Bond) did not degrade after 1 year when compared with a similar self-etch adhesive that did not incorporate the MDPB resin monomer.

MOST COMMON CLINICAL APPLICATIONS OF CLEARFIL™ SE PROTECT

As a board-certified endodontist, the author uses CLEARFIL™ SE Protect as an antimicrobial adhesive to establish coronal seal after finishing root canal treatment to prevent reinfection of the peri-radicular tissues via coronal leakage through the filled root canals (Figure 1 and Figure 2). Another common use of CLEARFIL™ SE Protect is the restoration of the access cavity prepared through a zirconia-based full-coverage restoration. By taking advantage of the MDP component, the author feels more confident that he can bond to the zirconia with a resin composite without causing leakage along the composite-zirconia interface.

Disclaimer: This article was provided by Dr. Tay.

Fig 1. Preoperative radiograph of tooth No. 18. Diagnosis: pulpal necrosis with symptomatic api-cal periodontitis.

Fig 2. Postoperative radiograph of tooth No. 18. Coronal seal was created with radiolucent antimicrobial self-etching adhesive (CLEARFIL™ SE Protect, arrow) and a radiopaque flowable composite, followed by placement of a cotton pellet and a temporary restoration.

ADVANCED NEW FEATURES FOR MORE CONFIDENCE

Studies show that the risk of bacteria remaining in cavities tends to increase with smaller minimal intervention cavities (S. Imazato; Dent. Mater. J. 2009).

CLEARFIL™ SE Protect contains a new functional monomer MDPB, which exhibits an “Antibacterial Cavity Cleansing Effect” (Fig 3).

Fig 3. The bactericidal mechanism of MDPB is presumed to be similar to the well-known antibacterial agent CPC**, which is in many toothpastes and mouth rinses. **Cetyl pyridinium chloride

EXCEPTIONAL RESEARCH RESULTS

Increased durability of resin-dentin bonds

Recent research has demonstrated that MDPB is also an effective inhibitor of matrix metaloprotinases (MMP) that may deplete collagen.

The advantage of MDPB over chlorhexidine (CHX) is that it polymerizes with adhesive resins and cannot leach from the hybrid layer.

(Pashley et al. Compend Contin Educ Dent. 2011)

Fluoride-release

CLEARFIL™ SE Protect contains a patented, specially treated sodium fluoride (NaF); the NaF in CLEARFIL™ SE Protect is coated with a unique polymer capsule that allows release of NaF while the bonding layer physical properties, including strength, are maintained.

Simple proven procedure - avoid technique sensitivity

CLEARFIL™ SE Protect is a two bottle primer and adhesive bonding system.

• No scrubbing needed to achieve good bond strength to tooth structure
• No shaking required Bond itself maintains homogeneity and creates no worries in the quality of the first and last drop of adhesive.

DIRECT RESTORATION

Follow the standard procedures for isolation, moisture control, cavity preparation and pulp protection.

Dentist:

FRANKLIN TAY, BDSC (HONS), PHD

Franklin Tay is Professor and Chair in the Department of Endodontics, College of Dental Medicine, Georgia Regents University, Augusta, Georgia, and a Fellow of the Academy of Dental Materials, as well as a Diplomate of the American Board of Endodontics. With more than 400 papers published in peer reviewed journals, his research interests include biomineralization of collagen scaffolds with apatite and/or silica, remineralization of resin-dentin bonds, antimicrobial sol-gel chemistry, mesoporous silica, and endodontic materials.

First published in COMPENDIUM, April 2014, Volume 35, Number 4.

For the placement of veneers, a resin cement must be selected that supports long-lasting aesthetics, is easily applied, offers a working time sufficient for simultaneous cementation of multiple restorations and provides excellent bond strength. The new “PANAVIA™ Veneer LC” is precisely what you need.

For the pretreatment of the tooth you can use PANAVIA V5 Tooth Primer as shown in our previous workflow video.

BUT did you know that CLEARFIL Universal Bond Quick is also an option? Today’s video demonstrates exactly how. Check it out!

Direct restoration procedures simplified

Some companies mainly make use of basic technologies developed by others to improve their products and introduce new ones, while other companies conduct fundamental research and technology development inhouse. Is this difference relevant for someone who uses the resulting products in the dental practice or laboratory on a daily basis? It is – as companies developing everything from scratch usually have a deeper understanding of the products and their production procedures, which makes it easier for them to modify specific features, solve existing problems and respond to market needs. This article describes the impact of several basic technologies developed by Kuraray Noritake Dental Inc. on the workflow of creating direct composite restorations.

Direct restorations – from complex to simple

Adhesive restorative dentistry using high-performance dental adhesives and resin composites is currently one of the most popular way of treating teeth with carious lesions. Nowadays, a single-bottle universal adhesive and one or two shades and opacities of universal composite are usually enough to create beautiful and durable outcomes, provided that the right materials are selected.

This, however, has not always been the case. For a long time, the techniques used to create direct restorations have been quite complex: adhesives were technique-sensitive multi-bottle and multi-step systems with long application times. Composite filling materials, on the other hand, only produced lifelike outcomes when many different shades and opacities were combined in the right way. And even if the complex procedures were carried out correctly, the risk of microleakage, discolouration and eventually secondary caries was comparatively high. Kuraray Noritake Dental Inc. focused on solving these issues quite early, starting with the utilization of the Original MDP Monomer developed in 1981.

Optimizing the bonding performance

The Original MDP Monomer addressed the issue of limited long-term bonding performance of adhesive systems. MDP’s hydrophilic (phosphate) group forms a particularly strong and long-lasting chemical bond with calcium found in hydroxyapatite, the main component of enamel and dentin. The formed MDP-Ca salt provides the basis for a stable, strong and durable hybrid layer. In combination with the resin in the bonding agent a tight seal of the cavity after light-curing is the result. Down to the present day, MDP is an essential component of any adhesive product from Kuraray Noritake Dental Inc., and it is the key component that made CLEARFIL™ SE Bond become the Gold Standard self-etch adhesive system.

However, convinced that dental adhesives should provide for more than just a strong and long-lasting bond, Kuraray Noritake Dental Inc. started to focus on solving another issue: the risk of demineralization and cavitation caused by bacteria remaining in the cavity. Based on its experience in developing other adhesive monomers, Kuraray Noritake Dental Inc. invented the MDPB monomer that has an antibacterial cavity cleansing effect. Different from antibacterial agents that might impair the bond strength of a subsequently applied adhesive, the MDPB monomer kills remaining bacteria without affecting the bonding performance. It is contained in the primer of the two-bottle self-etch adhesive CLEARFIL™ SE Protect and is immobilized by polymerization.

The bactericidal mechanism of MDPB is presumed to be similar to the well-known antibacterial agent CPC (Cetyl pyridinium chloride), which is in many toothpastes and mouth rinses.

While two-bottle self-etch adhesives has already simplified the adhesive procedure, single-bottle universal adhesives go the extra mile. It is a challenge to bring together ingredients distributed in multi step systems in one bottle without compromising the stability of the product. Current technology now makes this possible. To seal the surface as soon as possible after application, the penetration of the monomers into the dental tissue must be fast and efficient. However, the penetration is usually slowed down by monomers that need time to penetrate the tooth structure – especially wet dentin – and sometimes even need to be rubbed into it. That is why Kuraray Noritake Dental Inc. focused on developing the Rapid Bond Technology. It consists of the Original MDP Monomer combined with newly developed hydrophilic crosslinking amide monomers and is integrated in CLEARFIL™ Universal Bond Quick. The hydrophilic amide monomers provide for a rapid, deep and complete penetration of the dentin and form upon curing a densely cross-linked polymer network responsible for a strong and durable bond. Hence, waiting and rubbing times are eliminated and a tight and long-lasting seal of the cavity is established after light-curing.

Due to their hydrophilicity (water-affinity), the amide monomers of the Rapid Bond Technology penetrate dentin very well. After light-curing, the bond exhibits low water sorption and therefore high aging-resistance.

Optimizing direct restoratives

Combining multiple layers, shades and opacities: The use of highly complex layering techniques for the creation of lifelike composite restorations is luckily a thing of the past in many clinical situations. The reason: highly developed resin composites that blend seamlessly with the adjacent tooth structure. To provide for this favourable feature, Kuraray Noritake Dental Inc. has developed its proprietary Light Diffusion Technology (LDT). The technology is incorporated in special pre-polymerized fillers acting like millions of micro-prisms that transmit and refract light and colour from the surrounding tooth structure. Optimized in size, distribution and refractive index in relation to the matrix, the fillers offer unsurpassed natural blending.

The whole CLEARFIL MAJESTY™ composite line-up contains this proprietary filler technology. Its latest product – CLEARFIL MAJESTY™ ES-2 Universal – in which Kuraray Noritake Dental Inc. makes use of next level LDT allows for a single-shade technique with simplified shade selection: it is available in two shades for the anterior and a single shade for the posterior region, but blends in so nicely that it covers virtually every shade of the VITA classical A1-D4 shade guide.

Refracting and transmitting light in the right way for a great optical integration: light diffusion fillers of CLEARFIL MAJESTY™ ES-2 from Kuraray Noritake Dental Inc.

As a great optical appearance is not only dependent on optical integration and undetectable restoration margins, Kuraray Noritake Dental Inc. also developed fillers that provide for the rest – a natural surface gloss and long-term polish retention. The solution integrated in CLEARFIL MAJESTY™ ES Flow with its three levels of flowability is called Submicron Filler Technology, which consists of glossy submicron-sized fillers. These fillers are so small that light reflections show a natural effect even after wear. Kuraray Noritake Dental Inc.’s exceptional silane technology is used to join millions of those submicron fillers and keep them together over time. It allows for high filler loads in the low-viscosity composites and limits water uptake that would otherwise lead to degradation of the cured composite. The perfect balance between the glossy submicron fillers, light diffusion fillers, resin matrix and proprietary silane technology is responsible for a balanced combination of mechanical and optical properties.

Example of a single-shade restoration made of CLEARFIL MAJESTY™ ES-2 Universal.

Conclusion

Adhesive monomers, filler technologies and silane technology providing for a solid combination of fillers, clusters and resin matrix: Kuraray Noritake Dental Inc. clearly is a trusted expert in the field of adhesive restorations. The proprietary technologies developed during the past decades have definitely contributed to a better (long-term) performance of direct restorations, and to reliable and aesthetic outcomes more easily achieved.