Glem frustrasjonen over flow-kompositter. Finnes det en flow-kompositt som holder det den lover? Noen av flow-komposittene på markedet har utilstrekkelig styrke og estetikk, og er vanskelige å bruke. Dette kan gi inntrykk av at flow-kompositter er underlegne i forhold til pasta-kompositter. La oss forklare hvorfor CLEARFIL MAJESTY™ ES Flow skiller seg fra andre flow-kompositter på markedet og se hvordan avansert silaniseringsteknikk åpner for en ny æra innen flow-kompositter.

Hovedkomponentene i dentale kompositter inkluderer fillere og resiner som kombineres omhyggelig for å gi et anvendelig materiale som kan polymeriseres og som kan gi en holdbar dental restaurering. Det er essensielt at fillerpartiklene forblir i matrisen. For å oppnå dette, må fillerpartriklene feste seg til matrisen. Et bindemiddel (silan) letter den kjemiske adhesjonen mellom de to komponentene i kompositten. Silan er et bifunksjonelt, overflateaktivt materiale som binder til fillerpartiklene og reagerer med monomerene i matrisen under polymeriseringen.

SKIKKELIG SILANISERING 

Det kan virke enkelt, men virkeligheten er annerledes.. Når man blander filler og resin oppstår et problem. Mengden av f iller som kan tilsettes er meget begrenset. Meget raskt vil blandingen bli så hard at den blir nesten umulig å jobbe med. Dagens kompositter inneholder fillerpartikler som blir stadig mindre i størrelse. Ved et konstant volum, vil overflaten som skal dekkes med resin øke når partiklene blir mindre, og dette fører til at blandingen blir ubrukbar enda raskere. Det trengs derfor høykvalitets silaner slik at fuktekapasiteten til f illerpartiklene blir så høy som mulig. Dette gir en kompositt av høy kvalitet.

DET USYNLIGE MESTERVERKET

Ikke alle silaner og silaniseringsteknikker er like. Kuraray Noritake Dental viser et av sine mesterverk på dette området. Vi, som er ledende innen silanisering, bruker bare svært stabile spesialtilpassede silaner. Et av silanene som brukes er et spesialutviklet langkjedet silan. Long Carbon Chain Silane (LCSi). Dette silanet brukes i vår serie med flow-kompositter med høyt fillerinnhold: CLEARFIL MAJESTY™ ES Flow.

Resultatene av vår fremragende  silaniseringsteknologi:

• Høyt fillerinnhold uten at det går på bekostning av brukervennlighet
• Høy stabilitet på restaureringene selv etter påkjenninger
• Høy fuktresistens
• Holdbare restaureringer med naturtro utseende
• Svært lav vannabsorpsjon
• Optimale håndteringsegenskaper

Fig. 1: Blandinger av samme mengde resin og ulikt behandlede fillerpartikler. Til venstre: Ubehandlet, i midten: Konvensjonell silanisering, Til høyre: Kuraray behandlet.

Jo høyere kvalitet det er på silanet, desto bedre blir fuktbarheten til fillerpartiklene og desto mere filler kan tilføres til resinet uten at det går ut over håndteringsegenskapene . En tilleggsfordel ved å bruke vårt høykvalitets silan er at det bidrar til at fillerpartiklene ikke løsner så lett fra herdet kompositt. Våre kompositter har også svært begrenset vannopptak, og dette er også relatert til vår silanteknologi.

Kombinasjonen av fillerne, den før nevnte silanteknologien og en resin med lav viskositet, gjør oss istand til å skape en f low-kompositt med høyt fillerinnhold som fungerer som en universalkompositt.. Både flytegenskapene og den optimale brukervennligheten beholdes, samtidig som kompositten har høy styrke.

Fig. 2: Jo mere sofistikert silanteknologien er, desto mere filler kan tilsettes samme mengde resin.

FLYTEGENSKAPER

CLEARFIL MAJESTY™ ES Flow-familien tilbyr tre ulike viskositeter for å matche dine preferanser og type restaurering: High, Low eller Super Low.

STYRKE

CLEARFIL MAJESTY™ ES Flow har et fillerinnhold på opptil 75% (vekt), 59% (volum), og dette fører til fremragende (mekaniske) egenskaper slik at det er velegnet også for posteriore restaureringer.

HVA BETYR DETTE FOR DEG?

Hvilke fordeler gir vår ekspertise deg som tannlege?

Blant annet på grunn av den høye fillerandelen har restaureringer fremstilt av CLEARFIL MAJESTY™ ES Flow meget høy styrke. Tilstrekkelig styrke også for posteriore restaureringer. CLEARFIL MAJESTY™ ES Flow er faktisk sterkere enn de fleste konvensjonelle kompositter med pastakonsistens. (se diagrammet nedenfor). Gjentatt belastning påvirker ikke styrke og integritet negativt. Materialet er også motstandsdyktig mot fuktighet, og dette gjør at materialets styrke og estetikk holder seg stabile over lang tid. Fillerpartiklene i CLEARFIL MAJESTY™ ES FLOW består av både submikron- og klyngepartikler (0,18 til 3,5 mikrometer). De attraktive bruksegenskapene som f.eks. kontrollert applisering og at materialet ikke renner og siger, skyldes i stor grad den balanserte sammensetningen av f illere.

Typen fillerpartikler er også i stor grad ansvarlig for den holdbare høyglansen til restaureringene som er fremstilt av CLEARFIL MAJESTY™ ES Flow. De kan poleres i løpet av noen få sekunder, og selv bare å tørke av overflaten med en bomullsrull med sprit på, gir god høyglans. Lysdiffusjonsteknologien i CLEARFIL MAJESTY™ ES Flow, som hovedsaklig skyldes nanocluster fillerne, gir fremragende fargematching og gjør at restaureringen går sømløst i ett med omgivende tannvev.

KONKLUSJON

Man kan trygt si at vår ekspertise innen silanisering og andre teknologier (som f.eks. Light Diffusion Technology), har en stor positiv effekt på kvaliteten av komposittene våre, inkludert CLEARFIL MAJESTY™ ES Flow. Denne kommer i tre ulike grader av flytbarhet og tilbyr en svært anvendelig produktserie med enkel håndtering, høy styrke, enkel polering og holdbar høyglans. Enten du ønsker å bruke den til å restaurere, reparere eller sementere, anteriort eller posteriort, eller til Stamp Technique eller Flowable Injection Technique eller en hvilken som helst annen teknikk, er dette den eneste kompositten du trenger.

Viktigheten av høykvalitets protetisk behandling

Høy kvalitet på behandlingen er trolig det viktigste elementet på veien til tilfredse pasienter. Ved hvert enkelt besøk, ønsker  pasienten å føle seg ivaretatt av kompetent tannhelsepersonell, mens tid i stolen og antall konsultasjoner bør reduseres til det nødvendige minimum. I protetisk sammenheng betyr dette at en restaurering skal passe perfekt med én gang og være holdbar, for å unngå omgjøringer og ekstra tannlegebesøk.

Men hvordan er det mulig å levere høykvalitets restaureringer med perfekt tilpasning hver gang? Blant potensielle årsaker til problemer med kvaliteten på indirekte restaureringer er feil som gjøres på klinikken eller på laboratoriet, problemer med kommunikasjonen, og ofte noe som blir oversett, bruk av zirkonium av dårlig kvalitet.

Zirkoniumrestaureringer, moderne og estetiske dentale løsninger.

For over 20 år siden kom zirkonium inn på dental-markedet som en erstatning for metall ved fremstilling av kroner og broer. Begge materialer, zirkonium og metall, ble vanligvis kombinert med et lag porselen som var brent på metallet eller zirkoniumet. I de følgende årene fokuserte flere av de ledende dentalprodusentene (som f.eks. Kuraray Noritake Dental Inc.), på materialforbedringer. Disse forbedringene transformerte gradvis materialet fra  et opakt, hvitt kjernemateriale til et keramisk materiale med et tannlignende utseende og fremragende mekaniske egenskaper. De nyeste zirkonium-variantene som finnes med ulike grader av translucens og styrke, anses av tannbehandlere over hele verden for å være det beste behandlingsalternativet for et bredt utvalg av pasienter og indikasjoner. Én grunn er at de trenger bare et tynt lag porselen eller ikke porselen i det hele tatt. En annen grunn er at de trenger liten veggtykkelse, slik at de muliggjør konservativ preparering, samtidig som de har lang levetid. Vel å merke hvis man bruker et høykvalitets materiale.

Kvalitetsforskjeller på dentalt zirkonium

Kvaliteten på zirkonium kan variere avhengig av faktorer som renheten på råmaterialet (ikke bare zirkoniumet, men også alumina, yttria, fargetilsetninger osv.), den nøyaktige kjemiske sammensetningen, kornstørrelsen og partikkelfordelingen. Hvert trinn i fremstillingsprosessen (pulverblanding pressing,pre-sintring) har innvirkning på kvaliteten på diskene (optiske og mekaniske egenskaper).

Vanlige problemer som oppstår pga. zirkonium av dårlig kvalitet.

Problemer med de optiske egenskapene til en restaurering (translucens, fargeavvik, overgang mellom lagene på multi-layered materialer), vil alltid vise seg etter sintringen på laboratoriet. Det kan bli nødvendig å lage den om igjen. Andre ganger kan feilen oppdages først ved innprøving på pasienten, og dette vil ofte føre til at pasienten blir misfornøyd. Det samme vil være tilfelle for kasus med dårlig passform grunnet f.eks. inhomogen materialstruktur. Det som er enda verre, er dårlig biokompabilitet, som dårlig overflate, svake kanter, nedsatt bøyestyrke eller nedsatt bruddstyrke. Disse problemene kan ofte bare påvises med dyrt testutstyr som normalt ikke er tilgjengelig på et tannteknisk laboratorium. Dette betyr at feil vanligvis ikke oppdages før det oppstår et klinisk problem, som f.eks gingival retraksjon, økt plakk-akkumulering, slitasje, eller en feil som gir ubehag og smerter.

Oversikt over potensielle problemer og kliniske konsekvenser for pasienter

Sertifisering og standardisering av dentalt zirkonium

Dette er grunnen til at spesialister har utviklet en ISO standard (ISO 6872:2015), som beskriver in vitro tester som alle produsenter må gjennomføre på dentalt zirkonium som skal anvendes i Europa og USA, for å få FDA-godkjenning og CE-merking. De beskrevne testene brukes for å måle bøyestyrke og bruddstyrke, som antagelig er de viktigste egenskapene for langtids holdbarhet av restaureringer av materialet. Alle materialer som brukes i Europa og USA må bestå disse testene.

Hvordan du skal unngå å plassere zirkonium med lav kvalitet i dine pasienters munn

Derfor burde alle som bruker disse sertifiserte zirkoniumproduktene være trygge og i stand til å minimere materialrelatert risiko. Men den økende populariteten til dentalt zirkonium har tiltrukket seg interesse fra firmaer som vil ha en bit av kaken uten å ta bryderiet med å sikre høy produktkvalitet og gjennomgå sertifisering. Usertifiserte produkter som mangler CE-merking, har en ting felles, de utgjør en risiko for bedriften din og pasientene dine.

Så hvordan er det mulig å sikre produktkvaliteten på zirkonium på klinikken? Den gode nyheten er at det er noen enkle forholdsregler. Ved å følge dem, unngår du å sette inn piratprodukter eller lavkvalitets zirkonium i dine pasienters munn.

Tre gyldne regler for å gi pasientene dine høykvalitets zirkonium-restaureringer:

• Bestill bare produkter som er produsert innenlands eller i en region med samme standarder som dine egne: Restaureringer som produseres i dentallaboratorier i Kina, for eksempel, har lavere krav til godkjenning (derfor mangler de CE-merking),og oppfyller antagelig ikke dine forventninger.
• Snakk med ditt (norske) dentallaboratorium om hvor de får zirkoniumen sin fra: Forviss deg om at de kjøper zirkonium fra ledende produsenter (som f.eks. Kuraray Noritake Dental Inc.) gjennom autoriserte forhandlere.
• Unngå tilbud som er for gode til å være sanne: Lave priser kan virke fristende, men den endelige kostnaden for en behandling kan lett bli høyere enn vanlig når komplikasjoner inntreffer.

Hvordan bruk av sertifisert zirkonium kan påvirke pasientene dine over tid.

Ved å forvisse deg om at zirkoniumen du bruker på klinikken din oppfyller de høyest mulige kvalitets-standarder, bidrar du til å bygge opp pasientenes tillit og positive inntrykk over tid. Selv om den første kostnaden for høykvalitets zirkonium er noe høyere enn for dårligere varianter, kan totalkostnadene bli lavere fordi restaureringene holder lengre og man unngår omgjøringer. En fornøyd pasient  er ofte bedre til å følge opp munnhygieneregimer, og de er mer lojale. Dette gir deg bedre rykte og hjelper til å bygge praksisen din.

Undersøk mulighetene og velg produkter fra sertifiserte produsenter.

Hvis du ønsker å ta et steg videre, kan du sammenligne sertifiserte zirkoniumvarianter fra flere produsenter og oppdage forskjeller. Kuraray Noritake Dental Inc. f.eks., er den eneste produsenten som utfører hele produksjonsprosessen, inkludert produksjon av råvarer, i egen bedrift. På denne måten har selskapet kontroll over hvert eneste trinn og kan sørge for en fremragende produkt-kvalitet, uansett hvilken variant du velger. Med det tilgjengelige produktutvalget som består av KATANA™ Zirconia UTML (ultra-translucent, muylti-layered), KATANA™ Zirconia STML (Superior translucent, multi-layered) og den høytranslucente multilayered HTML PLUS og YML (med økt styrke og gradert translucens), er det mulig å dekke så å si enhver indikasjon.

Article by Dr. Clarence Tam HBSc, DDS, FIADFE, AAACD

A NOVEL MDP-BASED SURFACTANT SOLUTION

The everyday practice of adhesive restorative dentistry, whether utilizing direct or indirect restorations, is fraught with the need for ideal environmental conditions to generate an optimal prognosis. The bonding of composite resin is the foundation of direct and indirect restoratives, as it provides the link between restoration and tooth. As dentistry strives to be minimally invasive, the treatment of the bonding interface is reflected in this philosophy by the use of self-etching multi-substrate acidic monomers such as 10-methacryloyloxyldecyl dihydrogen phosphate (10-MDP). There are myriad opportunities for both intaglio and fitting surfaces to be contaminated with varying agents to the detriment of restoration prognosis.

Some of the contaminants to be considered are of course, moisture from exhalation, ambient humidity in the oral cavity, blood, saliva and artificial sources such as provisional cement during a two-stage indirect delivery technique. Moisture is an agent which is only welcomed via a controlled approach during the dentin penetration phase of priming the substrate for adhesion, however if excessive in quantity will compromise the hybridization of the interface. Blood and saliva are ubiquitous in restorative dentistry, and best controlled via the application of rubber dam as part of an absolute isolation philosophy. Contamination of the prepared surface can also occur through artificial cements or lubrication agents. Hemostatic agents such as ferric sulfate and aluminum chloride have the ability to deposit insoluble precipitates on the surface of the tooth in a manner that 33% orthophosphoric acid can only partially remove. Also considered is the particulate deposition of dentin and enamel as part of standard tooth preparation. This smear layer is residual on the dentin surface, often occludes dentinal tubules, and is an obstacle that must be overcome in order to bond to the hydroxyapatite and collagen fibrils of the surface.

Overall, the risks to adhesive compromise and at worst, adhesive failure are high. This report details the use of a novel solution for debriding both indirect restorative and tooth intaglio with a 10-MDP salt-based solution that has the flexibility to be used both extraorally and intraorally.

ENDEMIC CONTAMINANTS: MOISTURE, BLOOD AND SALIVA

Moisture is a critical component to maximize the adhesive bond strength of certain modern universal adhesives. The presence of moisture allows for increased penetration of bonding solutions into dentinal tubules and between collagen fibrils, ultimately bolstering the resilience of the hybrid layer¹. During the cementation of an indirect restoration, both salivary and blood contamination of the mating surfaces have been shown to have a deleterious effect on bond strengths, with blood contamination faring the worst in all conditions². Van Meerbeck et al reported on technique sensitivity with one-step contemporary universal adhesives³. The basis of his findings note that these adhesives require water as an ionization medium for the self-etching reaction, with the need to evaporate water from the interfacial surfaces in order to maximize bond strengths. Despite this, these interfaces are considered semi-permeable which predisposes the hybrid layer to an increased risk of hydrolytic degradation in adhesive solutions that are not 2-hydroxyethyl methacrylate-free (HEMA-free), which has a greater affinity for water.

Periera et al tested varying degrees of wetness of dentin substrate controlled with variables such as short vs. long air blasts, wet vs. dry cotton pellets, microbrush use and an intentionally over-wet surface. In all groups, the “wettest” dentin intaglio surface resulted in the lowest shear bond strength⁴.

The influence of saliva and blood contamination is clearly negative in situations where the bonding interface was contaminated before or after adhesive application. For saliva, this reduction is due to the deposition of salivary glycoprotein on the surface, and relative to blood, macromolecules such as fibrinogen and platelets block access to the tubules for effective bonding. Blood contamination was found consistently to be more profoundly deleterious on bond strength relative to saliva².

In general, on smear layer-affected dentin, chlorhexidine was consistently superior to other agents such as ethanol, EDTA, aloe vera in establishing the highest shear bond strength to dentin. On dentin that had previously been etched and contaminated with blood and saliva, the agent subsequently applied that showed the highest recovery of shear bond strength was 37.5% phosphoric acid⁵. A study on the nanomechanical and nanoroughness of etched dentin and self-etching adhesive treated dentin both contaminated with saliva revealed that KATANA™ Cleaner was capable of restoring control values of complex modulus and nanoroughness relative to control⁶.

SYNTHETIC WORKFLOW CONTAMINANTS: DENTAL STONE, HEMOSTATIC AGENTS, ROOT CANAL SEALERS AND PROVISIONAL CEMENTS

A 2020 study by Marfenko et al demonstrated that salivary contamination showed significantly lower bond strengths relative to intaglio contamination by dental stone from laboratory processes. The application of a silane coupling agent to the intaglio surface has a protective effect on the bond strength⁷. The caveat is that lithium disilicate-based restorations are often requested pre-etched with hydrofluoric acid from the laboratory. Often, the case is returned to the clinician on the secondary or primary model. If already treated with hydrofluoric acid, the surface can now be considered recontaminated with the stone or resin model or simply skin oils from handling. The unprotected surface needs to be decontaminated in any case following the try-in procedure, which now may feature elements of dental stone, blood and saliva, not to mention hemostatic agents such as aluminum chloride and ferric sulphate. If silane coupling agents are applied prior to try-in, the question of whether the intaglio surface was truly contaminant-free after removal from the model.

Aluminum chloride is a hemostatic agent that leaves an insoluble precipitate on the surface of the dentin, that is only partially removed when treated with phosphoric acid, resulting only in a partial recovery of shear bond strength relative to control. The application of ethylene diacetyl tetrasodium acetate (EDTA) returned the bond strengths to the level of normal dentin⁸. The bonding of polycrystalline ceramic restorations and metal alloys is contaminated with saliva upon try-in. This can be removed via steam cleaning and air particle abrasion set at 2.5 bar for 15 seconds⁹. Phosphoric acid is often mistakenly applied as a cleaning agent to the intaglio surface. In polycrystalline ceramics such as tetragonal zirconia polycrystal, this is disastrous, as phosphates will bond firmly to the free sites that the 10-MDP monomer normally bonds to as part of the APC protocol of zirconia bonding, significantly compromising bond strength (Blatz, 2016)¹⁰. A study of modern surface cleaners demonstrated successful debridement of the surface using KATANA™ Cleaner for both blood and saliva-contaminated substrates^{11, 12}.

Provisional cements are thought to have a deleterious effect on the shear bond strength of adhesively-bonded indirect ceramic restorations. Ding et al (2022) uncovered that resin-based and non-eugenol cement use in the provisional phase decreased the bond strength relative to control, whilst the use of calcium hydroxide and polycarboxylate cements exhibited acceptable metrics. Debridement of the prepared surface with air particle abrasion (APA) resulted in recovery of decreased bond values to that of control¹³. Equally useful was the application of Immediate Dentin Sealing (IDS)¹⁴, a technique characterized ideally by APA before adhesive bonding and the application of a resin coat, occluding both the dentin tubules as well as the oxygen inhibition layer, allowing the resin-dentin bond to mature and strengthen in the absence of stresses. This approach is effective in minimizing post-operative hypersensitivity and bacterial ingress, as well as optimizing the shear bond strength particularly when indirect ceramics are concerned¹⁵. Hardan et al found that the shear bond strength was highest when IDS was completed using a three-step etch and rinse adhesive protocol¹⁴.

Hemostatic agents used in clinical dentistry exhibit a pH of 1.1 to 3.0 and are as acidic as self-etching primers¹⁶. Chaibutyr and Kois found that dentin when contaminated with 25% aluminum chloride or 13% ferric sulphate demonstrated a significantly lower shear bond strength to dentin, which was significantly recovered using the etch-and-rinse approach¹⁷. This approach albeit successful was only able to achieve partial reversal of shear bond strength deficits relative to control, with a pre-etching application of EDTA required in order for full recovery⁸. KATANA™ Cleaner was found to have a positive effect on the cleaning of dentin contaminated with both aluminum chloride and ferric sulphate.

The bonding of dentin substrate contaminated with root canal sealers is a concern for the integrity of core buildups post-endodontic treatment. The use of  KATANA™ Cleaner was found to be generally superior to the ethanol test subgroup in the removal of zinc-oxide eugenol-based sealer with equal performance to 70% ethanol for the epoxy resin-based sealer¹⁸.

CLINICAL CASE DEMONSTRATION

A 35 year old ASA 1 female patient presented to the practice with multiple failing composite restorations in the second quadrant that were planned for replacement. Prior to the delivery of topical and local anaesthesia, it is common procedure in the practice to ascertain shade specifics of planned restoratives before potential dehydration can affect the optical properties of the natural tooth. Smart monochromatic composites (Fig. 1) are a class of direct restoratives that leverages the ability of its nanofiller composition and refractive index to mimic the structural color of the surrounding enamel and dentin¹⁹. This typically enables a clinician to have a simplified selection of shades on hand.

Two carpules of 2% Lignocaine with 1:100,000 epinephrine were delivered via buccal infiltration before absolute isolation was achieved using a non-latex rubber dam (Isodam HD Heavy, 4D Rubber, UK) (Fig. 2). The old restorations were excavated along with caries (Fig. 3), and the dentin structure assessed for residual decay with a detector dye (Caries Detector, Kuraray Noritake Dental Inc.). The preparation cavosurface margins were gently bevelled before surface treatment with air particle abrasion (30psi, 29 micron aluminum oxide in a 17.5% ethanol carrier, Aquacare UK) (Fig. 4). The enamel margins were etched with 33% orthophosphoric acid and rinsed (Fig. 5). The preparation surfaces were decontaminated further of any residual smear or powder residue using a MDP-based surfactant (KATANA™ Cleaner, Kuraray Noritake Dental Inc.) (Fig. 6). A single step self-etching universal adhesive was applied to the preparation as per manufacturer instructions and air thinned before light curing (Fig. 7).

Fig. 1

Fig. 2

Fig. 3

Fig. 4

Fig. 5

Fig. 6

Fig. 7

A matrix-in-matrix approach was utilized for the second bicuspid as the first step to allow for simultaneous anatomic construction of the mesial and distal marginal ridges. This technique does not require the use of a wedge as the outer circumferential Tofflemire matrix (Omnimatrix, Ultradent Products) tightens cervically around the inner anatomically-curved sectional matrix (Garrison Firm Band, Garrison Dental Solutions) allowing for a hermetic gingival seal (Fig. 8). If required, the setup may be further modified by the use of Teflon inserted between the two matrices to provide better proximofaciolingual adaptation. As a result, finishing and contour creation post-band removal is kept to a minimum. Following this, a traditional sectional matrix system may be employed to close contacts and build marginal ridges in the conventional manner (Fig. 9).

Following marginal ridge construction, the matrix assembly was removed and with the Class II lesions converted into a Class I situation, microlayering proceeded with a high flexural strength flowable liner (CLEARFIL MAJESTY™ Flow, Kuraray Noritake Dental Inc.) prior to the application of a monochromatic composite resin (CLEARFIL MAJESTY™ ES-2 Universal U shade, Kuraray Noritake Dental Inc.). The buccal cusps were constructed first as the author considers this essential to establishing restoration lobe proportions (Fig. 10). Subsequent layers were completed in a lobe-by-lobe approach to finish the occlusal anatomy (Fig. 11 and 12). The restoration was checked for occlusal functional conformativity, finished and polished to high shine (Fig. 13).

Fig. 8

Fig. 9

Fig. 10

Fig. 11

Fig. 12

Fig. 13

DISCUSSION

Dental substrates are often contaminated in both direct and indirect restorative processes. Historically, etch-and-rinse approaches have been successful for at least the partial recovery of bond strength however it is not practical in situations where selective or self-etching is the adhesive strategy. The restorative dentist in these cases can use the 10-MDP monomer in self-etching systems to target non-demineralized dentin such as CLEARFIL™ Universal Bond Quick to establish an acid base resistance zone (ABRZ) otherwise known as Super Dentin²⁰. The presence of the operative smear layer impedes full access of the self-etching primer to the dentin substrate in some cases. In such cases, without KATANA™ Cleaner, APA is required to transform the substrate back to control bonding potential. APA as a modality is only utilized by a subset of dental practitioners often due to financial constraints or lack of technique experience. KATANA™ Cleaner thus represents a versatile tool for the decontamination and  optimization of substrate surfaces for adhesive bonding both in intraoral and extraoral applications. Its ability to re-establish ideal bonding values in areas that are not effectively reached by APA such as endodontic canal anatomy in a non-invasive manner literally cements it as a truly indispensable tool for the modern restorative dentist.

Disclaimer: Some indications are not described in the product’s Instructions for Use and are based on published research and/or the author’s experience. Before using each product, read carefully the Instructions for Use supplied with the product for full details and workflows.

Dentist:

CLARENCE TAM

References

1. Sugimura R, Tsujimoto A, Hosoya Y, Fischer NG, Barkmeier WW, Takamizawa T, Latta MA, Miyazaki M. Surface moisture influence on etch-and-rinse universal adhesive bonding. Am J Dent. 2019 Feb;32(1):33-38. PMID: 30834729.
2. Taneja S, Kumari M, Bansal S. Effect of saliva and blood contamination on the shear bond strength of fifth-, seventh-, and eighth-generation bonding agents: An in vitro study. J Conserv Dent. 2017 May-Jun;20(3):157-160. doi: 10.4103/0972-0707.218310. PMID: 29279617; PMCID: PMC5706314.
3. Van Meerbeek B, Van Landuyt K, De Munck J, Hashimoto M, Peumans M, Lambrechts P, Yoshida Y, Inoue S, Suzuki K. Technique-sensitivity of contemporary adhesives. Dent Mater J. 2005 Mar;24(1):1-13. doi: 10.4012/dmj.24.1. PMID: 15881200.
4. Pereira GD, Paulillo LA, De Goes MF, Dias CT. How wet should dentin be? Comparison of methods to remove excess water during moist bonding. J Adhes Dent. 2001 Fall;3(3):257-64. PMID: 11803713.
5. Haralur SB, Alharthi SM, Abohasel SA, Alqahtani KM. Effect of Decontamination Treatments on Micro-Shear Bond Strength between Blood-Saliva-Contaminated Post-Etched Dentin Substrate and Composite Resin. Healthcare (Basel). 2019 Nov 1;7(4):128. doi: 10.3390/healthcare7040128. PMID: 31683858; PMCID: PMC6956069.
6. Toledano M, Osorio E, Espigares J, González-Fernández JF, Osorio R. Effects of an MDP-based surface cleaner on dentin structure, morphology and nanomechanical properties. J Dent. 2023 Nov;138:104734. doi: 10.1016/ j.jdent.2023.104734. Epub 2023 Oct 2. PMID: 37793561.
7. Marfenko S, Özcan M, Attin T, Tauböck TT. Treatment of surface contamination of lithium disilicate ceramic before adhesive luting. Am J Dent. 2020 Feb;33(1):33-38. PMID: 32056413.
8. Ajami AA, Kahnamoii MA, Kimyai S, Oskoee SS, Pournaghi-Azar F, Bahari M, Firouzmandi M. Effect of three different contamination removal methods on bond strength of a self-etching adhesive to dentin contaminated with an aluminum chloride hemostatic agent. J Contemp Dent Pract. 2013 Jan 1;14(1):26-33. doi: 10.5005/jp-journals-10024-1264. PMID: 23579888.
9. Yang B, Lange-Jansen HC, Scharnberg M, Wolfart S, Ludwig K, Adelung R, Kern M. Influence of saliva contamination on zirconia ceramic bonding. Dent Mater. 2008 Apr;24(4):508-13. doi: 10.1016/j.dental.2007.04.013. Epub 2007 Aug 6. PMID: 17675146.
10. 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. (7)
11. Awad MM, Alhalabi F, Alzahrani KM, Almutiri M, Alqanawi F, Albdiri L, Alshehri A, Alrahlah A, Ahmed MH. 10-Methacryloyloxydecyl Dihydrogen Phosphate (10-MDP)-Containing Cleaner Improves Bond Strength to Contaminated Monolithic Zirconia: An In-Vitro Study. Materials (Basel). 2022 Jan 28;15(3):1023. doi: 10.3390/ma15031023. PMID: 35160968; PMCID: PMC8838745.
12. Tian F, Londono J, Villalobos V, Pan Y, Ho HX, Eshera R, Sidow SJ, Bergeron BE, Wang X, Tay FR. Effectiveness of different cleaning measures on the bonding of resin cement to saliva-contaminated or blood-contaminated zirconia. J Dent. 2022 May;120:104084. doi: 10.1016/j.jdent.2022.104084. Epub 2022 Mar 3. PMID: 35248674.
13. Ding J, Jin Y, Feng S, Chen H, Hou Y, Zhu S. Effect of temporary cements and their removal methods on the bond strength of indirect restoration: a systematic review and meta-analysis. Clin Oral Investig. 2023 Jan;27(1):1530. doi: 10.1007/s00784-022-04790-6. Epub 2022 Nov 24. PMID: 36422719; PMCID: PMC9877054.
14. Hardan L, Devoto W, Bourgi R, Cuevas-Suárez CE, Lukomska-Szymanska M, Fernández-Barrera MÁ, Cornejo Ríos E, Monteiro P, Zarow M, Jakubowicz N, Mancino D, Haikel Y, Kharouf N. Immediate Dentin Sealing for Adhesive Cementation of Indirect Restorations: A Systematic Review and Meta-Analysis. Gels. 2022 Mar 11;8(3):175. doi: 10.3390/gels8030175. PMID: 35323288; PMCID: PMC8955250.
15. Samartzi TK, Papalexopoulos D, Sarafianou A, Kourtis S. Immediate Dentin Sealing: A Literature Review. Clin Cosmet Investig Dent. 2021 Jun 21;13:233-256. doi: 10.2147/CCIDE.S307939. PMID: 34188553; PMCID: PMC8232880.
16. Woody RD, Miller A, Staffanou RS. Review of the pH of hemostatic agents used in tissue displacement. J Prosthet Dent. 1993 Aug;70(2):191-2. doi: 10.1016/0022-3913(93)90018-j. PMID: 8371184.
17. Chaiyabutr Y, Kois JC. The effect of tooth-preparation cleansing protocol on the bond strength of self-adhesive resin cement to dentin contaminated with a hemostatic agent. Oper Dent. 2011 Jan-Feb;36(1):18-26. doi: 10.2341/09-308-LR1. Epub 2011 Feb 21. PMID: 21488725.
18. Tian F, Jett K, Flaugher R, Arora S, Bergeron B, Shen Y, Tay F. Effects of dentine surface cleaning on bonding of a self-etch adhesive to root canal sealer-contaminated dentine. J Dent. 2021 Sep;112:103766. doi: 10.1016/j.jdent.2021.103766. Epub 2021 Aug 5. PMID: 34363888.
19. Ahmed MA, Jouhar R, Khurshid Z. Smart Monochromatic Composite: A Literature Review. Int J Dent. 2022 Nov 8;2022:2445394. doi: 10.1155/2022/2445394. PMID: 36398065; PMCID: PMC9666026.
20. Nikaido T, Weerasinghe DD, Waidyasekera K, Inoue G, Foxton RM, Tagami J. Assessment of the nanostructure of acid-base resistant zone by the application of all-in-one adhesive systems: Super dentin formation. Biomed Mater Eng. 2009;19(2-3):163-71. doi: 10.3233/BME-2009-0576. PMID: 19581710.

Article by Dr. Clarence Tam HBSc, DDS, FIADFE, AAACD

A CHAMELEON SUPERCOMPOSITE

INTRODUCTION

The name of the game in modern-day esthetic and restorative dentistry is that of Responsible Esthetics. The goal of treatment typically strives to correct any structural and cosmetic shortfalls in both biologically-driven and trauma-affected teeth with the precise, artistic placement of various replacement layers, all whilst respecting and retaining a maximal volume of residual tooth structure. Anterior teeth can be affected by enamel and dentin dysplasia, caries and sclerotic conditions and are characterized by a laundry list of genetically-derived and environmentally-acquired conditions with an esthetic deficit that often threaten an individual’s functional and psychosocial integrity if not restored to the seamless picture of health.

Missing and defective tooth structure must be categorized into its attendant enamel and dentin components. Both substrates are distinctly different in composition, with enamel being highly inorganic in nature and dentin proportionately more collagenous in nature. The latter stratum is responsible for the refraction of light, the expression of the true color of the tooth, namely the hue and the endowment of fracture toughness or resilience in functional performance. The value and chroma are the other elements of color and are modified by the thickness of enamel. The replacement of enamel has been found to be best substituted from a biomechanical perspective by adhesively-bonded indirect porcelain restorations, and dentin using both composite resin and short fiber reinforced composite (SFRC), the latter imparting increased fracture toughness in large volume replacement restorations, especially those with pericervical structural deficits.

In adolescent patients, the gold standard of treatment involves direct composite resin, as often zero to minimal tooth structure preparation is required as a foundation to the bonded restorative. It would be impractical to use bonded indirect restorations when the development of the dentition in puberty is continuous, especially with the retraction of gingiva as one progresses to young adulthood. Resin composite allows prescience in the opportunity to predictably modify and/or add to the existing restoration if dental bleaching for the other teeth is desired or if a further traumatic incident is encountered. The ability to modify bonded porcelain is not predictable and frequent marginal failures occur due to a lower shear bond strength to bonded composite, especially after thermocycling. This is despite our ability to establish a chemical linkage via silane coupling agents from silicate ceramics to resin composite especially at a blended interface.

STATEMENT OF PROBLEM

Dental shades in clinical dentistry have long been classified using the VITA^* Classical A1 – D4 shade guide. Despite being ubiquitous in dental practices, composite resin systems with corresponding shade systems do not satisfactorily match to their purported shade¹. Floriani et al found that various mixtures of different shades in one system was required to achieve an acceptable color match with the VITA^* Classical shades using the CIEDE2000 formula. Testing another composite resin, they found that none of the A1, A2 or A3 shades matched acceptably to the standard shade guide². Indeed, even with indirect ceramic layering systems, a wide range of unacceptable discrepancy was noted between VITA^* labeled porcelain shades and the actual shade guide³. The VITA^* Classical shade guide became the standard in dental shade classification with the release of its A1-D4 shade guide in 1985. The majority of human-tested dental shades has been found to be in the A-family (78.5%), followed by C (13.2%), D (5.2%) and B (3.1%)¹. As such, the shade accuracy of a given composite system must be important if they are to be visually naturomimetic.

CHAMELEON EFFECT DEVELOPMENT

There are myriad composite resin systems featuring a simplified shade Universal system that have acceptable chameleon effects due to their balance of translucency, light transmission, diffusion and refractive index properties. There is a concern over how these optical properties may change after both thermocycling and wet storage, potentially compromising the excellent initial esthetic blend⁴. Refractive index (RI) is best optimized when the RI of the inorganic fillers match closely with the RI of the cured organic matrix, typically in a range between 1.47 and 1.52⁵. If the match is dissimilar, this drives up the opacity of the restoration due to heightened refraction and reflection at the filler/matrix interface⁶.

Layering of composite to mask an intraoral defect is complicated by the need to mask any linear defects such as fracture lines superimposed over the shadowing of the dark intraoral cavity in addition to regional color variations. It is confounded by the requirement to recreate natural maverick and translucent effects particularly in the incisal window region of upper and lower incisors and canines, giving the illusion of a virgin, healthy tooth. This has been historically difficult to accomplish in anterior teeth given the need to block out restorative interfaces with natural tooth structure and recreate a seamless internal structure and details. This detailed layer belies a well contoured enamel layer with realistic translucency, polishability and accurate primary and secondary anatomy.

Adding to the complexities described above, the histoanatomical approach to composite layering dictates that missing enamel is replaced by enamel shades, and dentin by the corresponding dentin shade in the appropriate shade. This shade must be selected at the very start of the appointment, as often even a minute of dehydration has a negative effect on both the perceptibility threshold and acceptability threshold of teeth⁷, resulting in the incorrect shade.

DEVELOPMENT

CLEARFIL MAJESTY™ ES-2 is a value-based super-nanofilled composite system that covers 15 VITA^* shades in just 4 shade options with its Universal series. This Universal series provides a chameleon effect and has 4 variants: Universal (U), Universal Light (UL), Universal Dark (UD) and Universal White (UW). It is the VITA^*-approved shading concept relative to color accuracy. Incorporating nano-fillers that consist of silanated barium glass fillers and slanted silica nanoclusters, its wear resistance is high and features minimal abrasiveness against the functional antagonist. The RI of both inorganic filler and organic matrix are well-matched, and the high refractive index of the composite mimics and is extremely similar to natural enamel (1.613) and dentin (1.540), thanks to an innovation labeled Light Diffusion Technology (LDT), which distorts light in a similar way dental tissue does⁸. There is comfort that the stability of refractive index and other optical transmission properties remains statistically stable even after artificial thermocycling and water-storage aging studies⁴. The color stability of CLEARFIL MAJESTY™ ES-2 has been proven over time, where a direct comparison to Filtek Ultimate showed CLEARFIL MAJESTY™ ES-2 to feature significantly less color variation from baseline and marginal functional wear over a three to four year period in teeth featuring amelogenesis imperfecta⁹. This color substantivity is important as dietary and environmental stressors applied over time should have as minimal effect on the restoration to ensure continued esthetic integration.

CLINICAL PROTOCOL

CLEARFIL MAJESTY™ ES-2 Universal is a monochromatic solution that covers the five key shades featured in the CLEARFIL MAJESTY™ ES-2 Premium. As such, it exhibits the most significant LDT relative to all five shades, as its ability is equal when blending to higher value translucent shades as it does to cervical chromatic shades. In a Class IV restoration with a defined fracture line, the challenge is to restore the tooth in a minimal volume of available space. The alchemy requires a complete visual occlusion of the fracture line position, and recreation of internal and external opaque and translucent anatomy along with maverick staining, craze lines and effects. In anterior teeth, the idiom of “the less you see, the less you notice” is not true, especially due to the presence of incisal edge window effects as above, however, materials with the best light diffusion and structure transference properties should be utilized to ensure the highest probability of success.

A 15 year old ASA I female presented to the practice exhibiting aged, chromatic composite restorations with poor marginal integration and gross axial overhangs; essentially a gross failure of primary anatomy and esthetics. She had been involved in a bike accident where she high-sided off braking sharply in a face-meets-concrete scenario, resulting in an uncomplicated moderate enamel-dentin fracture with blushing, affecting both the facial and palatal aspects of tooth 1.1 and a mild uncomplicated enamel dentin fracture affecting the distoincisobuccolingual aspect of tooth 2.1. The restoration overhangs were significant, extending into the proximal contour zone, thus obviating effective interdental cleaning. Vitality tests were confirmed along with radiographs to exclude the presence of apical pathology. The patient accepted the option of pre-prosthetic whitening, to improve the value characteristics of the adjacent teeth, allowing the selection of a brighter value shade combination. Intraoral digital scans were acquired and custom bleaching trays with a no reservoir, cervical seal-priority design were fabricated. The patient was instructed to bleach overnight for a 2 week period using a 10% carbamide peroxide solution (Opalesence, Ultradent Products, UT) until her maximal value was reached. Her baseline shade of the incisors was a 1M1/2M1 combination in the upper incisors and a 2M1 in the lower incisors. On final post-bleach assessment she exhibited a lightened shade of VITA^* 0M3 in all incisors. The patient was instructed to use a fluoride-containing, amorphous calcium phosphate complex (ToothMousse Plus, GC America) during the following 2 weeks after cessation of whitening whilst the residual oxygen radical species dissipated from the teeth.

Fig. 1. Pre-operative unrestricted smile 1:2 ratio view, teeth 1.1 and 2.1 with old, defective composite restorations with excessive chroma.

On the day of the procedure, the pre-dehydrated shade was assessed using the supplied “real composite” shade guide tabs featured in the CLEARFIL MAJESTY™ ES-2 Premium system, with the enamel shade being WE (White Enamel) and the dentin shade WD (White Dentin). It was assessed that both white maverick effects as well as a moderate halo effect was desired along with moderate to strong translucency in the incisal window.

The patient was anesthetized using 1.5 carpules of 2% Lignocaine with 1:100,000 epinephrine (Septodont) before a rubber affixed with individual ties for the central incisors (NicTone Medium). Excavation of the old restorative material was undertaken, and the residual natural incisal edge was found to be undermined by a through-and-through fracture. Thus, the preparation was converted into a true Class IV design, with the facioincisal cavosurface margin subjected to an infinity bevel. The maxillary central incisors were isolated from the lateral incisors by way of a serrated metal strip (Komet) and the prepared surfaces subjected to micro particle abrasion using a 29 micron aluminum oxide powder in 17.5% ethanol carrier (Aquacare). The surfaces were subsequently treated with a calcium sodium phosphosilicate powder (Sylc, Aquacare) to increase the inorganic content of the prepared surface especially extending into the exposed tubules. The teeth were etched using a 33% orthophosphoric acid before a 1 minute 2% chlorhexidine scrub (Vista Products). The surface was reduced to a moist dentin surface before the bond applied, air thinned and cured.

A Mylar strip was pre-crimped in the palatoproximal line angles and positioned on the linguoaxial surface of both teeth 1.1 and 2.1. There is no shade guide for the CLEARFIL MAJESTY™ ES-2 Universal U shade, as it bears a significant chameleon effect however it does come in a light (L) and dark (D) variant. The UL shade was deemed the most suitable for the palatal or lingual shelf, with an average thickness of 0.3mm. This layer was applied in a freehand fashion with a focus on establishing the desired outline form of the tooth relative to the contralateral 2.1. The Mylar matrix setup was removed and a precurved metal matrix (Garrison Slickband, Garrison Dental) was oriented in a position perpendicular to its normal placement interproximally, and the end of the curved band tucked into the sulcus before being secured by a wedge. In this way, there is light separation of the central incisors and an intimate contact between the matrix band and the mesial edge of the freshly applied lingual shelf. A 0.5mm frame extending more than halfway through the contact point was created and cured. The process was repeated on tooth 2.1 with the goal of recreating both lingual and proximal walls of the restoration, leaving only the facial volume to be replaced.

Fig. 2. Pre-crimped Mylar matrix repeated on the DIBP aspect of tooth 2.1 to close the available space. CLEARFIL MAJESTY™ ES-2 Universal UL is used here.

Block-out of the composite extensions against the natural tooth structure was achieved by opacification using an opaque composite resin (WD, CLEARFIL MAJESTY™ ES-2 Premium, Kuraray Noritake Dental Inc.) layered in both horizontal and vertical increments. It is noted that the restorative join line must be completely obscured at the end of layering the dentin volume, otherwise the case will have almost certain esthetic failure. The internal dentin anatomy and its inherent variation was created to mirror that of the 2.1, which had minimal compromise of its incisal window with details intact. A super translucent composite resin (Clear, CLEARFIL MAJESTY™ ES-2 Premium, Kuraray Noritake Dental Inc.) was placed between the lobes of the dentin layers and cured. A 9:1 ratio of white: orange tint was mixed and placed on the incisal edge and proximoincisal corners to recreate the halo effect. A pure white tint was placed in gentle dentin mamelon-connecting spider legs up to the incisal edge to impart the realism. This was layered in a manner consistent with the appearance of the 2.1.

Fig. 3. Both horizontal and vertical dentin composite increments are demonstrated mimicking the contralateral tooth.

Fig. 4 & 5. Final immediate post-operative result after finishing and polishing.

DISCUSSION

The esthetic merit of this case is foundationally supported by composite resin technology on multiple levels. The color and physical stability over time needs to be proven in order for the clinician to have faith in its prognostication. Specifically, the material needs to have an excellent and well-matched refractive index, and one that is unaffected by both water and thermocycling stressors.

The palatal shelf was fabricated using a new-generation super nano-filled universal composite system that boasts a strong chameleon effect. If it is our intention to fool the eye, to obscure, then this first layer works well to start the blockout process of the darkness of the mouth behind the fracture line of the restored tooth. Following this, the chroma and value of the tooth are corrected using the dentin, simultaneous to its continued opacification of the fracture line and intraoral darkness. Both dentin and enamel layers are applied histoanatomically, that is, in a manner respecting the various thickness zones observed in nature.

Ultimately, esthetic success in direct composite resin is not dictated on the first day post-operatively. Factors are in play, from dehydration to occlusal wrinkles that need to be ironed out and corrected. The win depends on what material is used, along with how that material was developed to what standards, and why shade accuracy is so important in a world of variety. In a dental world with myriad composite options, we are looking for precision. Precision in technology leads to efficiency and physicoesthetic maintenance in clinical results. This ultimately results in a boost to clinician-patient confidence and an optimal prognosis.

Dentist:

CLARENCE TAM

*VITA is a trademark of VITA Zahnfabrik, Bad Sackingen, Germany

References

1. Elamin HO, Abubakr NH, Ibrahim YE. Identifying the tooth shade in group of patients using Vita Easyshade. Eur J Dent. 2015 Apr-Jun;9(2):213-217. doi: 10.4103/1305-7456.156828. PMID: 26038652; PMCID: PMC4439848.
2. Floriani F, Brandfon BA, Sawczuk NJ, Lopes GC, Rocha MG, Oliveira D. Color difference between the vita classical shade guide and composite veneers using the dual-layer technique. J Clin Exp Dent. 2022 Aug 1;14(8):e615-e620. doi: 10.4317/jced.59759. PMID: 36046166; PMCID: PMC9422970.
3. Gurrea J, Gurrea M, Bruguera A, Sampaio CS, Janal M, Bonfante E, Coelho PG, Hirata R. Evaluation of Dental Shade Guide Variability Using Cross-Polarized Photography. Int J Periodontics Restorative Dent. 2016 Sep-Oct;36(5):e76-81. doi: 10.11607/prd.2700. PMID: 27560681.
4. Almasabi W, Tichy A, Abdou A, Hosaka K, Nakajima M, Tagami J. Effect of water storage and thermocycling on light transmission properties, translucency and refractive index of nanofilled flowable composites. Dent Mater J. 2021 May 29;40(3):599-605. doi: 10.4012/dmj.2020-154. Epub 2020 Dec 24. PMID: 33361663.
5. Arai Y, Kurokawa H, Takamizawa T, et al.. Evaluation of structural coloration of experimental flowable resin composites. J Esthet Restor Dent. 2020;e12674.
6. Ota M, Ando S, Endo H, et al.. Influence of refractive index on optical parameters of experimental resin composites. Acta Odontol Scand. 2012;70(5):362–367.
7. Suliman S, Sulaiman TA, Olafsson VG, Delgado AJ, Donovan TE, Heymann HO. Effect of time on tooth dehydration and rehydration. J Esthet Restor Dent. 2019 Mar;31(2):118-123. doi: 10.1111/jerd.12461. Epub 2019 Feb 23. PMID: 30801926.
8. Meng Z, Yao XS, Yao H, Liang Y, Liu T, Li Y, Wang G, Lan S. Measurement of the refractive index of human teeth by optical coherence tomography. J Biomed Opt. 2009 May-Jun;14(3):034010. doi: 10.1117/1.3130322. PMID: 19566303.
9. Tekçe N, Demirci M, Sancak EI, Güder G, Tuncer S, Baydemir C. Clinical Performance of Direct Posterior Composite Restorations in Patients with Amelogenesis Imperfecta. Oper Dent. 2022 Nov 1;47(6):620-629. doi: 10.2341/21-106-C. PMID: 36281978.

2025 MARKS THE YEAR OF THE SNAKE

Case by CDT Mathias Berger, France

Every patient is unique. Their specific backgrounds, functional needs and aesthetic demands need to be respected in any prosthodontic treatment plan. However, the importance of an individual treatment approach increases with the number of teeth to be replaced: After all, the impact of the restorations on facial aesthetics and on the patient’s quality of life is never greater than when all teeth are missing. Fortunately, adequate dental materials and techniques are available for a patient-centered, individual approach, no matter what challenges need to be overcome.

A patient with bruxism

In the present case, an elderly male patient with bruxism was in need of a new maxillary denture. Since the placement of five implants in the maxilla, he had no proprioception in this jaw. This lack of sensation had an impact on the overdenture to be produced: material and design needed to be carefully selected in a way that it would withstand uncontrolled chewing forces. As technical complications are easier to repair than biological complications, the overdenture should not be unbreakable – instead, the replacement of single units should be easily manageable.

Two-part denture design

The solution was a two-part design with a milled bar consisting of the gum area and tooth abutments (fig. 1) combined with single crowns. The material of choice for the bar was KATANA™ Zirconia HTML Plus (Kuraray Noritake Dental Inc.) with a uniform flexural strength of 1,150 MPa throughout the disc, while the single crowns were milled from KATANA™ Zirconia YML that offers natural translucency and strength gradation. While a monolithic design was selected for the posterior crowns, the six crowns for the anterior region received a micro-cutback for aesthetic micro-layering with CERABIEN™ ZR Porcelain. The shade scheme for individualization of the anterior crowns is shown in fig. 2. In a nutshell, customization was performed with the Internal Stains Cervical 1, Grayish Blue, Dark Grey and A+. The finishing layer on the incisors was created mainly using LT0 materials with some CCV-3 on the cervical and LT Natural on the mesial and distal lobes. On the canines, LT1 was used instead of LT0. The posterior crowns were merely finished with liquid ceramics (CERABIEN™ ZR FC Paste Stain, Kuraray Noritake Dental Inc.).

Fig. 1. Sintered bar milled from KATANA™ Zirconia HTML Plus.

Fig. 2. Chroma map for micro-layering in the anterior region.

Fig. 3 shows the finished single crowns with their individual, age-appropriate shade effects on the sintered bar. After checking the fit of the crowns, the gum areas of the bar were individualized using CERABIEN™ ZR Tissue Porcelain (fig. 4). Subsequently, the crowns were luted to the zirconia abutments (fig. 5), leaving screw access holes in aesthetically uncritical positions (fig. 6). The final overdenture ready for try-in is shown in fig. 7. Due to an excellent fit on the implants (fig. 8), it was possible to immediately fix the overdenture with the screws, close the access holes with composite and discharge the patient. The final appearance is shown in fig. 9.

Fig. 3. Finished crowns on the sintered bar.

Fig. 4. Bar with individualized gum areas.

Fig. 5. Placement of the central incisor crowns on the bar.

Fig. 6. Occlusal screw access hole in the finished overdenture.

Fig. 7. Overdenture ready for try-in.

Fig. 8. Intraoral try-in of the aesthetic overdenture.

FINAL SITUATION

Fig. 9. Treatment outcome.

CONCLUSION

This patient case is a good example of how important it is to respect the patient’s background, age and specific demands when producing dental restorations. Thanks to the great variety of restorative materials with different mechanical and optical properties available, it is possible to create suitable prosthetics for virtually every patient. However, for this purpose, it is important to stay up to date regarding new products launched and techniques developed. This way, it is often even possible to create beautiful and durable solutions in a simplified and efficient procedure such as micro-layering on innovative zirconia with a high aesthetic potential.

Dentist:

CDT MATHIAS BERGER

Satoshi Yamaguchi, President, Kuraray Noritake Dental Inc.

KURARAY NORITAKE DENTAL INC. EXCELS IN DENTAL TECHNOLOGY, FOCUSING ON STRENGTH, AESTHETICS AND GLOBAL ADAPTABILITY

Kuraray Noritake Dental Inc., a leader in dental materials and technology, blends innovation with a deep commitment to oral health. Established from the merger of Kuraray Medical Inc. and Noritake Dental Supply Co., Limited, the company excels in providing dental bonding agents, fillings, cements, porcelains, zirconia and CAD/CAM blocks. This synergy has allowed the company to push the boundaries of dental science.

“We aim to enhance global oral health and wellness.”

President Satoshi Yamaguchi highlights the company's approach: "We focus on strength, aesthetics and speed in our products. By developing our own zirconia powder and partnering with CAD/CAM system manufacturers, we achieve high-quality, durable and efficient dental solutions." This commitment is evident in the firm's flagship product, KATANA™ Zirconia Block, renowned for its durability and aesthetic appeal.

Kuraray Noritake Dental is also striving to develop new products for more longterm predictable dental treatment with bioactive properties. The company is not just focused on developed markets like the U.S. and Europe. Mr. Yamaguchi explains: "Understanding local treatment situations is key. In addition to the U.S. and Europe, having sales offices in places like Brazil and China helps us tailor our products to regional demands." This global presence ensures the company remains at the forefront of dental technology, adapting to diverse market needs.

Tooth crown made from KATANA™ Zirconia

Looking ahead, Mr. Yamaguchi envisions Kuraray Noritake Dental as more than just a technological innovator. "In five years, I hope we are seen not only as a tech company but as a holistic provider of oral care solutions," he says. With a commitment to reducing "invisible stress" for dental professionals and patients, the company aims to enhance global oral health and wellness.Original article published in Newsweek Magazine on September 20th, 2024 Written by The Worldfolio

Article by Dr. Florian Zwiener

Modern multi-layered zirconia such as KATANA™ Zirconia STML (Kuraray Noritake Dental Inc.) already meets high aesthetic demands due to its natural colour gradient and high translucency. To achieve further characterisation and optical adjustment to the adjacent teeth, there are essentially two options: veneering with feldspathic ceramic or glazing and individualisation with ceramic stains.

While there are still many indications for veneering, especially in the anterior area, more and more cases can now be solved with monolithic restorations. This allows for a time-efficient chairside workflow with same-day treatment, eliminating the need for temporary restorations. Additionally, the absence of a porcelain layer reduces the wall thickness of the restoration and thus the space required, allowing for less invasive preparation. This also reduces the risk of endodontic complications induced by tooth preparation (grinding trauma). Another advantage is a significant reduction in the chipping risk.

Below are the essential steps for individualisation using ceramic stains, demonstrated through the example of a molar crown.

PREPARATION

The restoration is designed in full contour as usual, ideally dry-milled, and then sintered. After sintering, the restoration is first sandblasted (aluminium oxide 50 μm, 1 to 1.5 bar pressure). This microscopic roughening of the ceramic surface enables an optimal bond with the glaze. Subsequently, the restoration should be cleaned using a steam cleaner or an ultrasonic cleaner to remove all blasting residue.

The functional restoration surfaces must then be polished to avoid the risk of excessive abrasion on the enamel of the opposing dentition, as zirconia is harder than enamel. Following this, optional glazing and characterization with ceramic stains can be performed. However, for areas not in the aesthetic zone, such as the palatal surfaces of maxillary anterior teeth, this is not necessarily required.

PREPARATION: STEPS AT A GLANCE

1. Sandblasting of the sintered restoration (Al2O3 50 μm, 1-1.5 bar)
2. Cleaning (steam cleaner or ultrasonic cleaner)
3. Polishing the occlusal/palatal contact areas

Fig. 1. Sintered and sandblasted zirconia crown.

Fig. 2. Occlusal high-gloss polish.

Fig. 3. TWIST™ DIA for Zirconia (Kuraray Noritake Dental Inc.) enables efficient polishing of zirconia in three steps.

STAINING AND GLAZING

The shades A+, B+, C+, and D+ of the paste-like ceramic stain CERABIEN™ ZR FC Paste Stain (Kuraray Noritake Dental Inc.) enhance the chroma in the cervical area when applied in the respective tooth shade. They are used to strengthen the multicolour effect of the zirconia or to darken the restoration overall. By mixing the stains with glaze or clear glaze in different ratios, the intensity can be adjusted.

Cervical 1 and 2 are suitable for replicating exposed cervical areas or discolouration. Cervical 1 is also useful for marking fissures, as it gives the crown depth and structure without appearing overly dark. Patients typically reject excessively pronounced fissure effects. Since fissure areas in multi-layered materials generally lie in the lightest part of the block (in the enamel layer), it may make sense to darken them slightly with A+, while white hypermineralisations can be replicated on the cusp tips. A narrow band of Grayish Blue below the cusp tips creates an optical translucency effect. In cases where this translucency appears too dark blue or greyish, mixing Grayish Blue with Dark Grey can modify the appearance.

By mixing various colours, numerous different tones can be created. For instance, by adding Yellow to A+, its slightly brownish colour can be adjusted to a warmer, more yellowish tooth shade. It is generally advisable to capture the patient‘s tooth shade with a photo and a custom-made colour ring of the corresponding material before preparation. This can serve as a reference during production, especially in the laboratory, where lighting conditions may differ.

For pronounced characterisations or fine details, it may be necessary to carry out multiple firings to avoid unwanted running effects between the colours and the glaze. This is particularly recommended when replicating anatomical details with high sharpness, such as enamel cracks or local discolourations. For this, a glaze and base shade are first applied and fired, and finer structures are added in a second firing. Alternatively, a fixative firing of the stains without glaze can be performed first, with only a glaze layer fired in the second step. A benefit of CERABIEN™ ZR FC Paste Stain is that its appearance during application closely matches the final firing result. In thick consistency, glaze can also be used to easily rebuild missing proximal contacts.

STAINING AND GLAZING: STEPS AT A GLANCE

1. Glaze with Glaze/Clear Glaze
2. Increase chroma (in the cervical area or over large areas) with A+, B+, C+, or D+
   - Adjust intensity by mixing with Glaze/Clear Glaze
   - Create a warmer tone by mixing with Yellow
3. Replicate discolouration/exposed cervical areas: Cervical 1 and 2
4. Customise fissure areas
   - Darken with A+, B+, C+, or D+
   - Accentuate fissures with Cervical 1
5. Customise cusp tips
   - Replicate hypermineralisations with White
   - Create a band below with Grayish Blue (translucency effect)
   - Adjust translucency effect below cusp tips by mixing with Dark Grey
6. Firing

Alternatives:

1. First firing: Glaze plus base shade, second firing: Finer structures
2. First firing: Fixative stain firing without glaze, second firing: Glaze firing

Fig. 4. CERABIEN™ ZR FC Paste Stain assortment for the practice laboratory.

Fig. 5. Discoloured fissures can be accurately replicated with an ISO10 endodontic file.

Fig. 6 and 7. Glazing and staining in one firing.

Fig. 8. Shade determination using a custom-made KATANA™ Zirconia STML colour ring (A3.5).

Fig. 9. Bridge made from KATANA™ Zirconia STML, sandblasted and occlusally polished.

Fig. 10. Finished glazed and characterised restoration.

Fig. 11. Bridge 14-16 in place.

FINAL SITUATION

Fig. 11. Bridge 14-16 in place.

Dentist:

FLORIAN ZWIENER

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

Anvendelse av skallfasetter av porselen for å forbedre form, farge og stilling på fortenner er en vanlig teknikk innen estetisk tannbehandling. Det biomimetiske målet ved tannrestaurering er ikke bare kosmetisk, men også funksjonelt. Det er avgjørende å huske på at det intakte emaljeskallet palatinalt og buccalt på anteriore tenner er ansvarlig for deres medfødte bøyestyrke. Når tannstrukturen er skadet ved endodontisk behandling, karies eller traumer, må ingen anstrengelser skys når det gjelder å bevare gjenværende tannstruktur og etterstrebe å gjenopprette eller øke styrken så den er på linje med en intakt tann.

BAKGRUNN

En 55 år gammel kvinnelig pasient tok kontakt på klinikken fordi hun ønsket å bleke tennene. Hun ble forklart at blekingen ikke ville ha effekt på en eksisterende skallfasett på 12. Denne ville måtte byttes ut etter blekingen. Pasientens utgangsfarge var VITA* 1M1 og 2M1 (på gingivale halvpart) Blekeprotokollen var nattbleking med 10% karbamidperoksid i 3-4 uker. Fargen var da VITA* 0M3 både på overkjeve og underkjeve. Det var derfor en vesentlig fargeforskjell på 12 og de øvrige tennene. Dessuten var en klasse III komposittfylling på 22 blitt mere synlig. Tann 22 matchet heller ikke 12 i dimensjon, og det ble derfor besluttet å fremstille skallfasetter av litium disilikat på begge lateraler. Tann 23 hadde mild attrisjon på cuspen, men pasienten ønsket ingen behandling av dette på det nåværende stadium. Behandlingen besto derfor i å etablere bilateral harmoni, for så å gjenopprette buccal kontur og cusp på 23 i nær fremtid.

BEHANDLINGEN

En digital smile design protokoll var ikke nødvendig for denne behandlingen, som besto i å behandle lateralene. En viss individuell og kjønnsbasert variasjon er vanlig for disse tennene. Før LA ble fargen for restaureringen tatt ut ved hjelp av fotos i polarisert og upolarisert lys.

Fig. 1. Referansefoto med 18% nøytral grått kort.

Grunnfargen (body) var Vita OM2 med en blokkfarge BL2. Pas ble bedøvd med 1,5 karpule med 2% Lignocaine med 1:100,000 adrenalin, før kofferdam ble satt på.(Split dam teknikk). Skallfasetten på 12 ble spaltet og fjernet fra tannen, og en minimal invasiv preparering gjort ferdig på 22 (Fig.2). Det ble gjort en delvis utskifting av den gamle komposittfyllingen mbp på12. Adhesjon til gammel kompositt ble oppnådd både ved sandblåsing og en silan (CLEARFIL™ CERAMIC PRIMER PLUS. Prepareringsgrensene ble frisket opp, og retraksjonstråd dyppet i aluminiumklorid-løsning ble pakket i sulcus. Fargen på de preparerte tennene ble notert. Endelig avtrykk ble tatt med light-body og heavy-body silikonmateriale i metall-skje. Pasienten fikk temporære restaureringer og fikk beskjed om å få fargen bekreftet på laboratoriet (grovbrent). Modellene som er fremstilt på laboratoriet bekrefter den minimal invasive fremgangsmåten.

Fig. 2. Preparering for skallfasetter på 12 og 22.

Da arbeidene kom fra laboratoriet, ble pas. bedøvd og provisoriene ble fjernet. Prepareringene ble rengjort og forberedt for bonding ved sandblåsing med 27 mikron aluminiumoksid-pulver med trykk på 30-40 psi. Skallfasettene ble prøvd på plass med innprøvingspasata (PANAVIA™ V5 Tryin- Paste Clear, Kuraray Noritake Dental Inc.). Retraksjonstråder ble plassert og adhesiv overflate på restaureringene ble behandlet med 5% flussyre i 20 sek. før silanet (CLEARFIL™ CERAMIC PRIMER PLUS) ble applisert. (Fig. 3). Tannoverflaten ble etset med 33% fosforsyre i 20 sek. og skylt. En primer med MDP (PANAVIA™ V5 Tooth Primer) ble så applisert på tannen (Fig. 4) og lufttørket som beskrevet i bruksanvisningen. Så ble sementen (PANAVIA™ Veneer LC Paste Clear) (Fig. 5) applisert og skallfasetten ble satt på plass. Overskuddssementen hadde en ikke-rennende konsistens og holdt skallfasetten på plass mens kanttilpasning ble sjekket, og ble så raskt lysherdet i 1 sek. (tack cure) (Fig.6).

Fig. 3. CLEARFIL™ CERAMIC PRIMER PLUS ble applisert på de flatene som skulle bondes.

Fig. 4. PANAVIA™ V5 Tooth Primer applisert på etsede tannflater.

Fig. 5. PANAVIA™ Venneer LC Paste Clear appliseres på skallfasettens innside.

Fig. 6. PANAVIA™ Veneer LC Paste Clear umiddelbart etter at fasetten er satt på plass. Legg merke til den viskøse, ikkerennende konsistensen som gjør det enkelt å fjerne sementen både i uherdet fase og i gel-fasen.

Sementen forvandles til gel-form, noe som gjør fjerning av overskudd og rengjøring av restaureringen mye enklere (Fig. 7). Kantene på restaureringen dekkes med en klar glycerin-gel før endelig herding for å eliminere oksygeninhibisjon. (Fig. 8).

Fig. 7. Fjerning av overskudds-sement etter lysherding i 1 sek. (tack-cure)

Fig. 8. Sluttherding av skallfasetter samtidig buccalt fra og palatinalt fra.

Kantene pusses til høyglans og restaureringene sjekkes i okklusjon og artikulasjon. Postoperative bilder viser usynlige skjøter (Fig. 9).

Fig. 9. Postoperativ estetisk tilpasning av skallfasetter på 12 og 22.

Vurdering med foto i polarisert lys viser at restaureringene er integrert både estetisk og funksjonelt (Fig. 10), Nå venter estetisk forbedring av tann 23 for å matche 13.

SLUTTRESULTAT

Fig. 10. Endelig resultat vurdert i polarisert lys.

Dentist:

CLARENCE TAM

References

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

Article by Dr. Michał Jaczewski

Komposittrestaureringer er den vanligste prosedyren som tannleger utfører. Det er mange teknikker og materialer som brukes innen restaurerende tannbehandling. Uavhengig av hvilke materialer og teknikker som brukes, er luftblærer inne i- eller på overflaten av komposittlagene et vanlig problem. Komposittrestaureringen bør være homogen for å sikre at fyllingen er tett og holdbar. Reparasjon av luftblærer er omstendelig og ofte kreves det at hele eller deler av fyllingen erstattes. Avhengig av type kompositt (flow eller vanlig) og/eller teknikken ved legging, vil antall defekter variere, men det er flere årsaksfaktorer.

Ved Flowable Injection Technique bruker vi flytende kompositt. Denne flyter selvfølgelig lett, men er også følsom for feilaktig applisering. Den første årsaken til at luftblærer oppstår, ligger i selve materialet. Blærer kan inkorporeres i sprøyten under fremstillingen eller ved appliseringen. Ved å bruke førsteklasses produkter kan vi være trygge på at både materialet og sprøyten er av en slik kvalitet at dannelsen av luftblærer inne i materialet reduseres så mye som mulig.

CLEARFIL MAJESTY™ ES Flow kompositt er designet for å forhindre dannelse av luftblærer under appliseringen. Den spesielle utformingen av sprøyte og stempel begrenser faren for drypping eller tilbakestrømming av materiale under eller etter applisering.

En unik sikkerhetsdetalj er den spesielle o-ringen inne i sprøyten som forhindrer at materialet fortsetter å komme ut etter at trykket på stempelet opphører og samtidig hindrer for stor tilbaketrekking  av stempel og materiale.

En annen årsak til luftblærer er at luft suges inn i sprøyten fordi stempelet trekkes tilbake av operatøren etter at materialet er applisert. Dette vil ganske sikkert suge luft inn i sprøyten slik at det vil dannes luftblærer ved neste gangs bruk.

Til Flowable Injection Technique bruker vi en silikonindeks som vi sprøyter komposittmaterialet inn i. Indeksen skal passe nøyaktig til tannen, og skal ikke kunne bevege seg under injeksjonen. Hvis den gjør dette, kan det dukke opp luftblærer. Å trykke og så slippe indeksen vil gi en sugeeffekt og trekke kompositten bort fra både indeksen og tannen. For å unngå defekter, må indeksen utsettes for konstant trykk fra det øyeblikket kompositten injiseres til den er ferdig polymerisert.

Forskjellige modifikasjoner av silikonindeksen kan brukes for å redusere mobiliteten og risikoen for ukontrollert press mot tannen. Et eksempel er en indeks som er laget på en modell hvor annenhver tann er vokset opp. Denne har en høy grad av stabilitet.

En annen grunn til at man får luft inn i restaureringen, er størrelsen på injeksjonskanalen. Hvis hullet er for trangt, vil indeksen kunne bevege seg når spissen på sprøyten settes inn eller under injeksjonen. For å unngå dette, må kanalen utvides så mye at spissen kan føres inn og beveges litt under injeksjonen. En videre kanal tillater også at luft kan unnslippe under appliseringen av kompositt. Viktigst er det imidlertid å injisere med jevnt trykk og å unngå å trekke ut og sette inn spissen under injeksjonen. Dette kan resultere i et komposittlag som ikke er ensartet.

Dentist:

MICHAL JACZEWSKI

Michał Jaczewski ble uteksaminert ved Wroclaw Medical University i 2006 driver i dag sin egen privatpraksis i byen Legnica, Polen. Han har minimal invasiv tannbehandling og digital tannbehandling som spesialfelt, og er grunnlegger av Biofunctional School of Occlusion. Her foreleser han og holder arbeidskurs med fokus på totalbehandling av pasienter.