Kvaliteetse proteesravi tähtsus

Kvaliteetne ravi on tõenäoliselt kõige olulisem aspekt patsiendi rahulolu saavutamiseks. Visiitide ajal soovib patsient tunda, et on oskusliku spetsialisti kätes. Ühtlasi on oluline vähendada visiidi aega ja arvu vajaliku miinimumini. See tähendab, et proteesravi kontekstis peab restauratsioon kohe täiuslikult sobima ja püsima ajas stabiilne, et vältida ümbertegemist ja lisakohtumisi.

Kuidas on aga võimalik iga kord paigaldada ideaalselt sobivaid ja kvaliteetseid restauratsioone? Indirektsete restauratsioonide kvaliteediprobleemide potentsiaalsed allikad on sageli hambaravikabinetis või laboris tehtud vead, kommunikatsiooniprobleemid ja – sageli tähelepanuta jäetud – madala kvaliteediga tsirkooniumi kasutamine.

Tsirkooniumrestauratsioonid – kaasaegne ja esteetiline hambaravilahendus.

Rohkem kui 20 aastat tagasi saabus tsirkoonium hambaravi turule metalli asendajana, mida kasutati kroonide ja sildade tootmiseks. Mõlemad materjalid – nii tsirkoonium kui metall – ühendati tavaliselt portselanikihi abil, moodustades seeläbi portselan-metall- või portselan-tsirkooniumrestauratsioonid. Järgnevatel aastatel keskendusid mitmed juhtivad tsirkooniumitootjad (nagu Kuraray Noritake Dental Inc.) materjali täiustamisele. Need täiustused muutsid järk-järgult algse valge läbipaistmatu raamistikumaterjali keraamiliseks materjaliks, millel on hambataolised optilised ja suurepärased mehaanilised omadused. Viimased tsirkooniumi versioonid, mis on saadaval erineva läbipaistvuse ja tugevusega, peetakse paljude hambaarstide poolt kogu maailmas parimaks võimalikuks ravivõimaluseks mitmesuguste patsientide ja näidustuste korral. Üheks põhjuseks on see, et nad vajavad vaid väikest või olematut portselanikihti. Teine põhjus on see, et need võimaldavad minimaalsete seinapaksuste korral säilitada pikaajaliselt loomulikke hambaid eeldusel, et kasutatakse kvaliteetset materjali. Rääkige laboripartneriga, kust nad saavad enda tsirkooniumi: veenduge, et tsirkoonium on pärit peamistelt tootjatelt ja volitatud edasimüüjatelt

Hambaravi tsirkooniumi kvaliteedi erinevused

Tsirkooniumist toodete kvaliteet võib varieeruda sõltuvalt erinevatest teguritest, nagu toorainete puhtus (mitte ainult tsirkoonium, vaid ka alumiiniumoksiid ja ütrium ning värvilisandid jne), täpne keemiline koostis, tera suurus ja osakeste jaotumine. Igal tooriku tootmisprotsessi etapil – alates pulbri valmistamisest kuni tooriku pressimise ja eelpaagutamiseni – on mõju lõplikule kvaliteedile, st ka tsirkooniumi mehaanilistele ja optilistele omadustele.

Madala kvaliteediga tsirkooniumiga seotud levinud probleemid

Kui restauratsiooni optilistel omadustel on midagi viga – selle läbipaistvusel, üldisel värvil või mitmekihilise värvistruktuuriga toorikute kihtide üleminekutel – tuleb probleem välja pärast lõplikku paagutamisprotseduuri laboris. See võib tingida ümbertegemise vajaduse või kui defekt avastada suhuproovimisel, võib see mõjutada negatiivselt patsiendi ravikogemust. Sama kehtib juhtude kohta, kus sobivus ei klapi näiteks materjali struktuuri ebaühtluse tõttu. Veelgi halvem on väiksem bioloogiline ühilduvus, pinna kvaliteet, servade stabiilsus, paindetugevus või murdetugevus. Need probleemid on tuvastatavad ainult väga kallite testimisseadmetega, mis pole tavaliselt hambaravilaborites kättesaadavad. See tähendab, et sellised vead jäävad tavaliselt märkamatuks, kuni ilmneb tõeline kliiniline probleem, nagu igemete taandumine, suurenenud hambakatu kogunemine, suurem kulumine või varajane rike, mis võib põhjustada valu ja ebamugavust.

Ülevaade võimalikest probleemidest ja kliinilistest tagajärgedest patsientidele

Tsirkooniumi sertifitseerimine ja standardimine

Ülaltoodud põhjustel on spetsialistid välja töötanud ISO standardi (ISO 6872:2015), mis kirjeldab in vitro teste, mida iga Euroopas või Ameerika Ühendriikides kasutatava tsirkooniumi tootja peab läbi viima, et saada FDA heakskiit ja CE-märgis. Kirjeldatud teste kasutatakse paindetugevuse ja murdumistugevuse mõõtmiseks, mis on tõenäoliselt kaks kõige olulisemat omadust, mis määravad materjalist valmistatud restauratsioonide pikaajalise käitumise. Kõik Euroopas või Ameerika Ühendriikides kasutatavad materjalid peavad olema need testid läbinud.

Kuidas vältida vähekvaliteetsest tsirkooniumist restauratsioonide paigaldamist patsientide suhu

Seega ei pea selle sertifitseeritud tsirkooniumi kasutajad muretsema ja saavad minimeerida materjaliga seotud riske. Kuid hambaravi tsirkooniumi kasvav populaarsus on tõmmanud ligi ettevõtteid, kes tahavad saada osa tulust tegemata pingutusi, mis on vajalikud toote kvaliteedi tagamiseks ja sertifitseerimiseks. Sertifitseerimata toodetel, millel puudub CE-märgistus, on üks ühine joon: need seavad kindlasti ohtu teie äri ja patsiendi.

Niisiis, kuidas on võimalik tagada hambaarstipraksises kasutatavate tsirkooniumtoodete kvaliteet? Hea uudis on see, et on olemas mõned lihtsad reeglid. Neid järgides suudate vältida võltsitud või vähekvaliteetsest tsirkooniumist restauratsioonide paigaldamist patsientide suhu.

Vältige võltsitud või vähekvaliteetsest tsirkooniumist restauratsioonide paigaldamist patsientide suhu.

Kolm kuldreeglit, et pakkuda oma patsientidele kvaliteetseid tsirkooniumrestauratsioone

• Tellige ainult kodumaiselt või kodumaaga sarnaste standarditega piirkonnas toodetud restauratsioone. Näiteks Hiinas toodetud restauratsioonid peavad vastama madalamatele standarditele (puudub CE-märgis) ja ei pruugi vastata teie ootustele.
• Rääkige (kodumaise) laboripartneriga, kust nad saavad enda tsirkooniumi: veenduge, et tsirkoonium on pärit peamistelt tootjatelt (nt Kuraray Noritake Dental Inc.) ja volitatud edasimüüjatelt, keda päriselt teate.
• Vältige liiga heade pakkumiste lõksu: madalad hinnad võivad olla ahvatlevad, kuid ravi lõplik maksumus võib tüsistuste tekkimisel olla isegi tavapärasest kõrgem.

Pikaajaline mõju patsientidele, kui kasutatakse sertifitseeritud tsirkooniumrestauratsioone

Kindlustades, et teie hambakliinikus paigaldatud tsirkoonium vastab võimalikult kõrgetele kvaliteedistandarditele, tagate ravitulemuste pikaajalisuse. Isegi kui kvaliteetse tsirkooniumrestauratsiooni algne kulu on veidi kõrgem kui madalama kvaliteediga restauratsiooni oma, võib üldine investeering olla väiksem, kui restauratsioonid kestavad kauem ega vaja ümber tegemist. Teie rahulolevad patsiendid on tõenäoliselt rohkem koostööaltid ja nõus suuhügieeni režiimi järgima, ning ühtlasi lojaalsed, avaldades positiivset mõju teie mainele ja kliendibaasile.

Uurige tsirkooniumi valikuid ja valige tooteid sertifitseeritud tootjatelt

Kui soovite veel põhjalikumaks minna, võite võrrelda erinevate tootjate sertifitseeritud tsirkooniumi valikuid ja tuvastada erinevusi. Näiteks Kuraray Noritake Dental Inc. on üks vähestest tsirkooniumi tootjatest, kes viib läbi kogu tootmisprotsessi, sealhulgas tooraine tootmise, ettevõttesiseselt. Sel viisil saab ettevõte kontrollida kõiki protseduuri aspekte ja pakkuda parima kvaliteediga toodet kõikide materjali variantide puhul. Saadaolevate toodetega KATANA™ Zirconia UTML (ülimalt läbipaistev mitmekihiline), KATANA™ Zirconia STML (eriti läbipaistev mitmekihiline) ning nii väga läbipaistev mitmekihiline HTML PLUS kui ka YML (tugevam ja läbipaistvuse gradatsiooniga) on võimalik katta peaaegu kõik ravinäidustused.

Professor Lorenzo Breschi artikkel

„Vähem pudeleid, rohkem valikuid“ on ehk kõige lühem viis universaalsete vaiktsementide eeliste kirjeldamiseks. Oma isesidustuva omaduse tõttu võimaldavad need kaksikkõvenevad vaigupõhised tsemendid paljudes kliinilistes olukordades ühekomponendilist töövoogu, ilma et oleks vaja eraldi hamba- ja restauratsioonipraimerit kasutada. Sel viisil saadud sidustugevus on tavaliselt piisavalt hea, et tagada stabiilne side hamba ja restauratsiooni vahel mitmesuguste näidustuste korral. Siiski on see veidi väiksem, kui on tavaliste mitmekomponendiliste vaiktsemendi süsteemidega saavutatav, mis koosnevad tavaliselt hambapraimerist, vaiktsemendist ja restauratsioonipraimerist.

Lisaks isesidustuvatele tehnikatele võib universaalseid vaiktsemente kombineerida ka täiendavate komponentidega, et suurendada sidustugevust hambastruktuuri või restaureerimismaterjaliga. See avab uusi võimalusi seoses toote kasutusega. Sõltuvalt vajalikust ja soovitud sidustugevusest võib universaalseid tsemente kasutada üksi või koos hambapraimeri, restauratsioonipraimeri või mõlemaga. Lisaks saavad võimalikuks hübriidkontseptsioonid. Seda uurib ka käesolev artikkel, mis keskendub näitena PANAVIA™ SA Cement Universal (Kuraray Noritake Dental Inc.).

Isesidustuv tsementimine paljude näidustuste korral

PANAVIA™ SA Cement Universal on kahekomponentne universaalne vaiktsement, mida kasutatakse laialdaselt isesidustuva tehnikaga. Sidustugevus restauratiivmaterjalidega (sealhulgas silikaatkeraamika) on suur, ilma et praimerit või silaani oleks eraldi vaja kasutada^1-4. Seda tänu kahele erinevale koostisesse kuuluvale adhesiivsele monomeerile - originaalne MDP-monomeer ja LCSi-monomeer (pika süsinikahelaga silaanist sidusaine, mis tagab tugeva keemilise sideme silikaatkeraamikaga). Seetõttu on võimalik kasutada vaiktsementi, ilma et restauratsiooni küljele oleks vaja lisada muid komponente – isegi retensiooni puudumisel ja seetõttu suure sidustugevuse vajaduse korral.

Isesidustuva tehnika korral saavutatakse tugev side emaili ja dentiiniga. Teatud olukordades võib aga olla kasulik suurendada sidustugevust hambastruktuuriga hambapraimeri abil.

Adhesiivtsementimine – keerukateks olukordadeks

PANAVIA™ SA Cement Universal soovitatakse kasutada hambapraimerit CLEARFIL™ Universal Bond Quick (Kuraray Noritake Dental Inc.). Selle kasutamist soovitatakse alati, kui kasutaja tunneb, et raviks on vaja erakordselt tugevat ja vastupidavat keemilist sidet, st eriti keerulistes olukordades, kus mehaaniline retentsioon on ebapiisav. Selle meetodi tõhusust on kinnitanud Jaapanis läbi viidud in vitro uuring, milles universaalse adhesiivi kasutamine suurendas oluliselt 24-tunnist sidustugevust dentiiniga⁵. Eraldi adhesiivi kasutamisel peab tööväli olema aga täiesti kuiv. Põhjus on selles, et vaiktsementide niiskustaluvus on tavaliselt suurem kui adhesiividel. Seetõttu soovitatakse tungivalt kasutada kofferdami.

Selektiivne adhesiivtsementimine: lühikeste toendite ja subgingivaalsete servade korral

Olukordades, kus töövälja on kofferdamiga isoleerida keeruline, soovitab üks Itaalia teadlaste rühm kasutada kolmandat tehnikat: selektiivset adhesiivtsementimist. Selle puhul kantakse CLEARFIL™ Universal Bond Quicki ainult ettevalmistatud hamba osadele, kus saab niiskust kontrolli all hoida, samas kui keerulistes kohtades, kus on keeruline saada soovitud kuiva töövälja, tuginetakse PANAVIA™ SA Cement Universali isesidustuvale omadusele. Selle tehnika jaoks sobivad olukorrad on subgingivaalse preparatsiooniservaga toendid ja eriti lühikesed toendid (mis takistavad kofferdami paigaldamist).

Selektiivse adhesiivtsementimise tehnika efektiivsust on kinnitatud in vitro uuringuga, mis võrdles kolme adhesiivstrateegia sidustugevust: isesidustuv tsementimine, täielik adhesiivtsementimine ja selektiivne adhesiivtsementimine⁶. Testide tulemused näitasid, et kasutajad saavad suurendada PANAVIA™ SA Cement universal sidustugevust dentiinil ja emailil, kandes adhesiivi ainult osale hambapinnast. PANAVIA™ SA Cement Universal ja CLEARFIL™ Universal Bond Quick koosneva tsemendisüsteemi korral andsid täielik adhesiivne ja selektiivne adhesiivtsementimine sarnaseid tulemusi.

Olukordades, kus töövälja on kofferdamiga isoleerida keeruline, soovitab üks Itaalia teadlaste rühm kasutada kolmandat tehnikat: selektiivset adhesiivtsementimist.

SOOVITATUD SAMMUD SELEKTIIVSEKS ADHESIIVTSEMENTIMISEKS

Joonis 1: hamba ettevalmistamine

Joonis 2. Emaili selektiivne söövitus fosforhappega

Joonis 3. Universaalse adhesiivi pealekandmine ja õhuga kuivatamine

Joonis 4. Krooni paigaldamine pärast vaiktsemendi kandmist krooni sisse

Joonis 5. Nakkekõvastumine.

Joonis 6. Liigse materjali eemaldamine ja lõplik valguskõvastamine

Joonis 7. Ravitulemus aasta möödudes

Selektiivse adhesiivtsementimise eelised

Lisaks soovitud suurenenud (pikaajalisele) sidustugevusele, mida saavutatakse eraldi adhesiivi kandmisel osale hambapinnast või kogu hambapinnale, pakub tehnika ka teisi täiendavaid eeliseid. Võrreldes mitmeastmeliste tsemendisüsteemidega, on protokoll lihtsam, kuna eraldi restauratsioonipraimerit pole vaja kasutada. Adhesiivi valguskõvastamine pole vajalik, kui kasutaja järgib soovitatud protokolli. Erinevalt täielikust adhesiivtsementimisest, mis nõuab kofferdami paigaldamist, pole selektiivse adhesiivstsementimise korral see etapp vajalik. Sellisel juhul väheneb tööaeg ja patsiendi jaoks on protseduur mugavam.

Järeldus

Vaiktsementide, nagu PANAVIA™ SA Cement Universal, kasutajad saavad valida tehnika sõltuvalt näidustusest, kliinilistest muutujatest ja individuaalsetest eelistustest, et saavutada parimad kliinilised tulemused. See on see paindlikkus ja lai kasutusala, mis muudab selle uuendusliku tootekategooria tõeliselt universaalseks. Vähemate komponentide kasutamise tõttu lihtsustavad universaalsed materjalid kliinilisi protseduure ja töövooge ning väiksem pudelite arv aitab töötajatel paremini kontrollida tellimusi ja inventari.

Dentist:

LORENZO BRESCHI

Professor Lorenzo Breschi töötab Bologna Ülikoolis restauratiivse hambaravi ja materjalide õppejõuna. Ta tegeleb aktiivselt emaili ja dentiini struktuuriliste aspektide uurimisega.

Ta on Hambaravimaterjalide Akadeemia (ADM) endine president ning

Euroopa Konservatiivse Hambaravi Föderatsiooni (EFCD), Hambaravi Materjalide Grupi IADR, Itaalia Konservatiivse Hambaravi Akadeemia (AIC), Rahvusvahelise Adhesiivse Hambaravi Akadeemia (IAAD) ametisse astuv president.

Viited

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Dentist:

JUSUF LUKARCANIN

Dr. Jusuf Lukarcanin is a Certified Dental Technician (DCT) and a Doctor of Dental Science (DDS). He studied dentistry at the Ege University Dental Faculty in Izmir, Turkey, where he obtained a Master‘s degree in 2011. In 2017, he received a Ph.D. degree from the Department of Restorative Dentistry of the same university. Between 2012 and 2019, Dr. Lukarcanin was the head doctor and general manager at a private clinic in Izmir.

Between 2019 and 2020, he worked at Tinaztepe GALEN Hospital as a Restorative Dentistry specialist, between 2020-2022 he worked at MEDICANA International Hospital Izmir as a Restorative Dentistry specialist. Currently he is an owner of a private clinic for aesthetics and cosmetics in Izmir.

Presented by Kuraray Noritake Dental Inc.

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

CURRENT STATUS AND FUTURE PROSPECTS OF ZIRCONIA RESTORATIONS

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

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

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

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

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

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

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

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

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

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

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

Maxillary 6 anterior monolithic crowns (Markus B. Blatz)

Fig. 1a and b: Initial examination.

Fig. 1c: Simulation of final prosthetic restoration.

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

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

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

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

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

Maxillary 4 Anterior teeth implant bridge (Naoki Hayashi)

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

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

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

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

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

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

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

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

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

Thank you very much for the meaningful discussion today.

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

Dentists:

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

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

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

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

KATANA Zirconia YML in a Nutshell

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

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

Colour Gradation and Physical Properties

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

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

Applications and Advantages of KATANA Zirconia YML

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

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

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

Revolutionizing Sintering with High-Speed Capabilities

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

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

Recommended Finishing Techniques for Optimal Results

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

KATANA Zirconia YML: A Testament to Innovation in Dental Materials

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

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

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

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

Mathias Fernandez Y Lombardi

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

With PANAVIA™ SA Cement Universal and KATANA™ Zirconia

By using PANAVIA™ SA Cement Universal and its proprietary dual-monomer technology, you can now simplify the bonding of restoration to implant abutments without the use of separate primers or silane. Independent research has confirmed this new dual-monomer technology does not sacrifice adhesion or durability on glass-based ceramics or zirconia. The technique, in this case study, is for custom fabricated abutment & KATANA™ Zirconia YML crown, however, the basic technique on the treatment of the abutment and restoration may be used with any implant restoration combination as long as the proper surface treatments for type of material is followed.

INITIAL FIT OF ABUTMENT & RESTORATION

Basic technique on the treatment of the abutment and restoration.

Fig. 1. Check Initial Fit of Abutment & Restoration: abutment & crown margins should be checked to ensure proper fit.

Fig. 2. Protect base of implant with putty or light-cure block-out resin. The base of the implant should be covered so that it is not air abraded accidentally.

Fig. 3. Abrade titanium abutment with 50 μm alumina oxide powder.

Fig. 4. Clean abutment with KATANA™ Cleaner: Apply KATANA™ Cleaner by rubbing each area for 10 seconds.

KATANA™ Cleaner is a universal cleaner that is indicated to clean metal, zirconia & glass-based restorations. It is also an intra oral cleaner that may be used on dentin and enamel.

TREATMENT OF KATANA™ Zirconia RESTORATION WORKFLOW

Bonding to zirconia has been proven to be durable in research going back to the 1990’s with the original MDP adhesive monomer in the PANAVIA™ resin cements. The three requirements to bonding zirconia are:

1. Air abrade zirconia with 50 μm alumina oxide powder.
2. Clean zirconia
3. Apply an MDP-Based Primer or resin cement. PANAVIA™ SA Cement Universal contains the original MDP that was developed & patented in 1981 by Kuraray Dental.

Fig. 1. Air abrade KATANA™ Zirconia at 14-58 psi.

Fig. 2. Dispense & mix PANAVIA™ SA Cement Universal (it is available in automix or handmix formulations).

Fig. 3. Apply PANAVIA™ SA Cement Universal to the abutment or inside the crown.

Fig. 4. Seat restoration on abutment.

Fig. 5. Remove excess resin with a dry micro-applicator or brush.

Fig. 6. You may light-cure the margins after cleaning up all excess resin. If you fully cure excess resin, It can be difficult to remove. If difficult to remove, change curing time or distance with your light.

Fig. 7. Leave restoration on abutment to self-cure fully for approximately 10 minutes at room temperature.

Fig. 8. Final check of custom abutment KATANA™ Zirconia YML crown on model.

Dentist:

JEAN CHIHA

Technician Jean Chiha CDT, Santa Ana, CA USA

Mr. Chiha is the owner of North Star Dental Laboratory and Milling Center, Santa Ana, CA, and has served as President of the Dental Lab Owners Association of California since 2013. He is a 1985 graduate of Institut Dento Technic, a private dental technology school in France. Mr. Chiha lectures internationally on dental communication and case planning. Jean lectures around the world on a variety of topics and has carved out a niche with his extensive knowledge of zirconia. Affectionately referred to as “Mr. Katana” due to his involvement in the creation of the material.

Case by Dr. Jusuf Lukarcanin

This young patient aged 35 with microdontia presented in the dental office with the desire to have more beautifully shaped teeth. His teeth were almost free of dental caries, but with deficiencies in oral hygiene and signs of gingival inflammation. A deep bite was also evident. After professional tooth cleaning and oral hygiene advice, the teeth were restored with CLEARFIL MAJESTY™ ES-2 Universal in the shade UL.

Fig. 1. Initial situation.

Fig. 2. Initial situation: Deep bite.

Fig. 3. Teeth restored with composite in the single-shade technique.

Fig. 4. Immediate treatment outcome.

Reasons for selecting universal light:

- For younger patients (tooth shades A2 and lighter)

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

Universal light properties:

- High light scattering effect

- Well-balanced translucency

Dentist:

JUSUF LUKARCANIN

Dr. Jusuf Lukarcanin is a Certified Dental Technician (DCT) and a Doctor of Dental Science (DDS). He studied dentistry at the Ege University Dental Faculty in Izmir, Turkey, where he obtained a Master‘s degree in 2011. In 2017, he received a Ph.D. degree from the Department of Restorative Dentistry of the same university. Between 2012 and 2019, Dr. Lukarcanin was the head doctor and general manager at a private clinic in Izmir.

Between 2019 and 2020, he worked at Tinaztepe GALEN Hospital as a Restorative Dentistry specialist, between 2020-2022 he worked at MEDICANA International Hospital Izmir as a Restorative Dentistry specialist. Currently he is an owner of a private clinic for aesthetics and cosmetics in Izmir.

With PANAVIA™ SA Cement Universal

By using PANAVIA™ SA Cement Universal and its proprietary dual-monomer technology, you can now simplify the bonding of any restoration to implant abutments without the use of separate primers or silane. Independent research has confirmed this new dual-monomer technology does not sacrifice adhesion or durability on glass-based ceramics or zirconia. The technique, in this case study, is for Ti-Base Implants, however, the basic technique on the treatment of the abutment and restoration may be used with any implant restoration combination.

TREATMENT OF TITANIUM ABUTMENT

Fig. 1. After attaching the abutment to the implant analog.

Fig. 2. Protect the base of the abutment with block out resin & light-cure.

Fig. 3. Air abrade the Titanium Abutment with 30-50 μm Alumina Powder @ 32 PSI.

Fig. 4. Clean abutment with KATANA™ Cleaner (10’s Rubbing, Rinse & Dry).

KATANA™ Cleaner is a universal cleaner that is indicated to clean metal, zirconia & glass-based restorations. It is also an intra oral cleaner that may be used on dentin and enamel.

REFERENCE INDEX POINTS TO ENSURE ACCURATE SEATING

Fig. 1. Mark Index position on implant analog.

Fig. 2. Mark index position (notch) on crown.

TREATMENT OF RESTORATION & BONDING TO THE ABUTMENT

Fig. 1. If Lithium Disilicate, HF acid etch Internal Surfaces, with 5% HF etch for 20’seconds then rinse & dry. If Zirconia, air abrade, at 14-58 PSI.

Fig. 2. Inject PANAVIA™ SA Cement Universal (White Shade) onto treated & cleaned abutment.

Fig. 3. Align index points & seat crown onto abutment.

Fig. 4. Place crown & implant into clamps & lightly tighten.

Fig. 5. Tack-Cure Clean-Up: Light-Cure excess cement for 2-5 seconds (time depends on light output & distance held).

Fig. 6. Remove excess cement & block-out resin with an explorer. PANAVIA™ SA Cement Universal has extremely easy clean-up.

Fig. 7. Wipe off remaining resin with gauze.

Fig. 8. Remove index mark with alcohol & gauze.

Fig. 9. Clean & polish restoration prior to seating. Surfaces coming in contact with soft-tissue should be polished.

Dentist:

GREG CAMPBELL

Dentist Greg Campbell DDS, Long Beach, CA USA

Greg Campbell, DDS is recognized internationally as an expert on integrating CAD/CAM dentistry into offices and is frequently sought out by industry leaders to lecture about Digital Dentistry. Dr. Campbell has a great understanding of Digital Technology and trains other dentists how to use this technology and is a certified Advanced CEREC Trainer. He is a former Beta tester for Sirona Dental and has authored two books on CAD/CAM dentistry. Dr. Campbell has created multiple polishing kits used for ceramics and has been trained on advanced adhesion materials, research & techniques and utilizing them clinically for over 8 years. Dr Campbell was an Alpha and Beta Tester for KATANA™ STML.

Dr. Campbell graduated from the University of Southern California School of Dentistry and completed advanced training in Cosmetic Dentistry at UCLA and maintains a private practice in Long Beach California.