429 Too Many Requests

Kompozītmateriālu restaurācija ir visizplatītākā procedūra, ko veic zobārsts. Zobārstniecībā tiek izmantotas daudzas restaurācijas metodes un dažādi restaurācijas materiāli. Neatkarīgi no materiāla veida, restaurācijas metodes un pielietošanas vietas, izplatīta problēma ir gaisa burbuļi kompozītmateriālu slāņos vai uz to virsmas. Kompozītmateriāla restaurācijai jābūt viendabīgai, lai nodrošinātu pildījuma hermētiskumu un tā izturību. Burbuļu defektu labošana ir apnicīga, un dažkārt ir nepieciešams nomainīt pildījumu vai tā daļu. Atkarībā no kompozītmateriāla veida (plūstošs vai pastas kompozītmateriāls) un/vai uzklāšanas tehnikas defektu daudzums var atšķirties, taču ir vairāki izraisošie faktori. 

Plūstošās injekcijas metodē mēs izmantojam plūstošus kompozītmateriālus, kas acīmredzami viegli plūst, bet ir arī jutīgi pret nepareizu uzklāšanu.  Pirmais gaisa burbuļu veidošanās cēlonis ir paša materiāla viendabīgums. Ražošanas posmā vai lietošanas laikā šļircē var veidoties burbuļi. Izmantojot augstākās kvalitātes produktus, mēs varam būt pārliecināti, ka tiek piegādāts augstākās kvalitātes materiāls un ka šļirces struktūra un dizains nodrošina pareizu darbību, lai samazinātu gaisa burbuļu veidošanos materiālā.

CLEARFIL MAJESTY™ ES Flow kompozītmateriāls ir izstrādāts, lai novērstu gaisa burbuļu veidošanos izspiešanas laikā. Šļirces un virzuļa īpašais dizains ierobežo materiāla pilēšanu kā arī atpakaļplūsmu izspiešanas laikā vai pēc tās.

Unikāla drošības funkcija šļirces iekšpusē ir īpašā O veida gredzena konstrukcija, kas neļauj materiālam plūst pēc spiediena atlaišanas un vienlaikus rūpējas par minimālu ievilkšanu, kā arī novērš virzuļa pārmērīgu ievilkšanos. 

Vēl viens gaisa burbuļu veidošanās iemesls ir gaisa iekļūšana šļircē apzināti ievelkot virzuli. Ja praktizējošajam ārstam vai palīgpersonālam ir ieradums pēc kompozītmateriāla ievadīšanas ievilkt virzuli, tas var izraisīt gaisa iekļūšanu šļircē. Turpmākās lietošanas laikā gaiss, visticamāk, parādīsies restaurācijā kā gaisa pora. 

Plūstošās injekcijas metodē mēs izmantojam silikona matricu kurā mēs ievadam materiālu, lai izveidotu zobu. Matricai ir cieši jāpieguļ zobiem un tā nedrīkst kustēties vai tikt pārvietota injekcijas laikā. Ja tā notiek, var parādīties gaisa burbuļi. Nospiežot un pēc tam atlaižot matricu radīsies piesūkšanās efekts un kompozītmateriāls tiks noņemts no zoba, kā arī no matricas. Lai izvairītos no defektiem, no materiāla injicēšanas brīža līdz polimerizācijai jāsaglabā matricas stabilitāte. 

Var izmantot dažādas silikona matricu modifikācijas, lai ierobežotu tās stabilitāti un samazinātu nekontrolēta spiediena risku uz zobu. Redzamais piemērs parāda matricas pareizu un nepareizu izvietojumu uz augšžokļa zobu modeļa, lai nodrošinātu augstu stabilitāti un darba efektivitāti. 

Vēl viens iemesls gaisa iekļūšanai restaurācijā ir injekcijas atveres platums. Ja atvere ir pārāk cieša, ievietošanas vai uzklāšanas laikā matricu var pārvietot ar uzklāšanas uzgali. Lai izvairītos no šīs problēmas, atveri var paplašināt, lai varētu brīvi ievietot, kā arī manipulēt ar uzgali injekcijas laikā. Plašāka atvere arī ļauj izplūst gaisam izspiešanas laikā. Tomēr vissvarīgākais ir uzklāt materiālu ar nepārtrauktu spiedienu un izvairoties no uzgaļa izvilkšanas un atkārtotas ievietošanas matricā.  Tā rezultātā var izveidoties nevienmērīgs kompozītmateriāla slānis. 

Dentist:

MICHAL JACZEWSKI

Mihals Jačevskis 2006. gadā absolvēja Vroclavas Medicīnas universitāti un šobrīd vada savu privātpraksi Legnicas pilsētā Polijā. Viņš specializējas minimāli invazīvā zobārstniecībā un digitālajā zobārstniecībā, kā arī ir Biofunkcionālās oklūzijas skolas dibinātājs. Šeit viņš lasa lekcijas un vada seminārus, koncentrējoties uz visaptverošu pacientu ārstēšanu

Intervija ar Dr. Michał Jaczewski

Plūstošās injekcijas metode kļūst par populāru tehniku, ko izmanto, lai estētiski restaurētu vairākus zobus ar plūstošu kompozītmateriālu. Mihals Jačevskis ir slavens pasniedzējs, kurš māca zobārstiem prasmes, kas nepieciešamas, lai veiksmīgi izmantotu šo tehniku. Viņš 2006. gadā absolvēja Vroclavas Medicīnas universitāti Polijā un kopš 2011. gada vada savu privātpraksi Legnicas pilsētā. Viņš ir Biofunkcionālās oklūzijas skolas dibinātājs, vada apmācības visaptverošās zobu ārstēšanas jomā, un aizraujas ar estētisko digitālo zobārstniecību. Starptautiskajā 2023. gada zobārstniecības izstādē Ķelnē viņš mums nodemonstrēja, kad, kāpēc un kā savā zobārstniecības kabinetā izmanto plūstošu injekciju. 

Vai jūs, lūdzu, varat aprakstīt šo tehniku dažos vārdos? 

Plūstošās injekcijas metode ir vienkāršs, paredzams, atkārtojams veids, kā atjaunot zobus, izmantojot plūstošu kompozītmateriālu. Tā ir balstīta uz izvaskojumu, kram tiek izgatavota silikona matrica. Šī matrica pēc tam kalpo kā atslēga plūstoša kompozītmateriāla injekcijai, kas tiek sacietināta gaismā caur caurspīdīgo silikonu. Vissvarīgākais ieguvums ir tas, ka šī metode darbojas gandrīz visos gadījumos ar ļoti minimālu zobu sagatavošanu. Tā ir minimāli invazīva metode, ko var izmantot gan iesācēji, gan pieredzējuši zobārsti. Izmantojot kompozītmateriālu ar labi sabalansētu necaurredzamību 0,3 mm biezumā un īpašu pulēšanas protokolu, ir iespējams sasniegt izcilus morfoloģiskos un optiskos rezultātus.

Kad sākāt izmantot plūstošās injekcijas metodi un kādas ir tās galvenās indikācijas? 

Es sāku izmantot šo metodi 2018. gadā. Sākotnēji tā tika izgudrota priekšzobu atjaunošanai, taču mūsdienās to veiksmīgi izmanto arī aizmugurējiem zobiem. Manuprāt, tas ir īpaši noderīgi ikreiz, kad ir jākoriģē vairāku zobu forma, lai uzlabotu pacienta smaidu neatkarīgi no tā, vai pacients ir jauns vai vecs. Piemēram, pēc ortodontiskās ārstēšanas. Zobus vienkārši iztaisno un pēc tam atjauno ideālā formā, izmantojot šo neinvazīvo tehniku. Plūstošo injekciju izmantoju arī smaida uzlabošanai, nodilušu zobu atjaunošanai un oklūzijas vertikālās dimensijas maiņai pilnīgas mutes rekonstrukcijas kontekstā. Pēdējā gadījumā restaurācija var būt īslaicīga un izmantota vidējam vai ilgtermiņa "testam". Tomēr tā var kalpot arī kā galīgā restaurācija. 

Kā sākt plānot pacienta zobu restaurāciju ar plūstošās injekcijas metodi? 

Vissvarīgākais posms, kas būtiski ietekmē šīs metodes panākumus, ir plānošanas posms. Tas sastāv no dokumentācijas, nospiedumu noņemšanas, vaskojuma izgatavošanas, kā arī silikona matricas izveides. Jūs, protams, varat strādāt tradicionālā veidā ar silikona nospiedumu un parasto vasku, taču digitālo tehnoloģiju izmantošana šajā posmā ievērojami uzlabos jūsu darba plūsmu. Es parasti sāku ar foto un video dokumentāciju un digitālo nospiedumu. Ir nepieciešami arī centrisko attiecību un oklūzijas rādītāji. Pēc tam, izmantojot digitālo smaida dizaina programmatūru, tiek izveidots digitāls vaskojums. Šajā solī ir svarīgi ņemt vērā pacienta sejas īpatnības. Tas ir uzdevums, ko vislabāk var paveikt, izmantojot sejas plūsmas koncepciju. Pamatojoties uz iegūto dizainu, virtuālo ārstēšanas rezultātu var parādīt un apspriest ar pacientu. Pēc apstiprināšanas izveidotais zobu vaskojums tiek izprintēts dažādās versijās: pilnais vaskojuma modelis un modelis ar mainīgu dizinu - viens zobs ar vaskojumu, kuram seko zobs bez tā. Šos modeļus izmanto, lai izgatavotu matricas no caurspīdīga silikona. 

Digitālais smaida dizains: pacients ar izteiktu zoba nodilumu. 

Pacienta mutē tiek parādīts digitālais vaskojums.

Modeļi tiek printeti uz digitālā uzvaskojuma pamata. 

Silikona matrica tiek izgatavota uz mainīga modeļa.

Kad un kāpēc jūs izgatavojat vairāk nekā vienu silikona matricu? 

Īpaši noderīgi ir strādāt ar pilno un mainīgo (daļējo) silikona matricu, plānojot atjaunot visus zobus augšžoklī. Ar mainīgo matricu man tiek nodrošināta papildus stabilitāte un tiek likts pamats precīzam rezultātam, īpaši attiecībā uz plānoto oklūzijas augstumu. Apakšžoklī, kur ir grūtāk rīkoties ar matricu un kompozītmateriālu siekalu klātbūtnes un kustīgu mīksto audu dēļ, vienmēr iesaku sadalīt darba lauku trīs daļās – vienā priekšējā un divās aizmugurējās daļās – un strādāt ar tiem atsevišķi. 

Kā jūs sagatavojat zobus un ievadāt plūstošo kompozītmateriālu? 

Vairumā gadījumu viss, kas mums nepieciešams, ir emaljas virsmu apstrāde cementēšanai, kas parasti ir iespējama ar gaisa strūklas apstrādi ar alumīnija oksīdu (50 µm zemā spiedienā). Pēc tam emalja tiek kodināta ar fosforskābes kodinātāju un universālu saiti. Tiek uzlikta matrica. Tā ir aprīkota ar injekcijas atveri incisālā malā. Tas ir viegli paveicams ar plūstošā kompozītmateriāla šļirces galu, kuru ir jāizspiež cauri matricai no iekšpuses uz ārpusi. Aizmugurējā rajonā ieteicams izmantot cietāku priekšmetu un katram zobam izveidot divus caurumus uz atsevišķām virsmām – vienu injekcijai un otru ārējai plūsmai. Cietajai matricai šai procedūrai ir nepieciešams dimanta urbulis. Es uzlieku matricu, injicēju plūstošo kompozītmateriālu no apakšas uz augšu, nedaudz gaismā sacietinu materiālu un noņemu matricu. Galīgo polimerizāciju veic pēc matricas noņemšanas un glicerīna gēla slāņa uzklāšanas. Kad liekais materiāls ir noņemts un restaurācijas proksimālā daļa ir perfekti pabeigta, procedūru atkārto pārējiem zobiem pirms restaurāciju pulēšanas. 

Vai jums ir kādi iecienītākie produkti šai metodei?

Silikona matricai izmantoju EXACLEAR (GC), jo tas ir caurspīdīgākais tirgū pieejamais silikons. Mans iecienītākais kompozītmateriāls plūstošai injekcijas metodei ir CLEARFIL MAJESTY™ ES Flow ar zemu viskozitāti (Kuraray Noritake Dental Inc.). Manā zobārstniecības kabinetā un kursu laikā man bija iespēja izmēģināt daudz dažādu produktu. Šajā kontekstā es atklāju, ka Kuraray Noritake Dental materiāls sniedz vairākas priekšrocības. Tas ir moderns nano kompozītmateriāla veids ar plašu indikāciju klāstu un lielu toņu piedāvājumu. Pateicoties tā trim viskozitātēm, to var izmantot daudzās dažādās klīniskās situācijās. Es sāku to lietot pirms pieciem gadiem, un plūstošās injekcijas metodei Low variants ir mana primarā izvēle, jo tas ir universālākais, kas piemērots priekšējiem un aizmugurējiem zobiem. Būtiskākās priekšrocības, kas ietekmēja manu lēmumu to izmantot, ir tā dabiskā estētika un izcilā pulējamība. Jūs varat iegūt iespaidīgu efektu bez īpašām prasmēm. Kā saistvielu es izvēlos izmantot CLEARFIL™ Universal Bond Quick, kas padara manu darba plūsmu vēl vienkāršāku, ātrāku un paredzamāku. Pulēšanai esmu izstrādājis savu protokolu.

Kā jūs beigās apstrādājat un pulējat savas restaurācijas? 

Es sāku proksimālajā zonā ar pulēšanas plāksnītēm un dažreiz proksimālo zāģveida loksnīti. Formas korekcijai trīs dažādi dimanta un karbīda urbuļi ir pierādījuši savu nozīmi. Pēc tam es izmantoju smalkus vai īpaši smalkus Sof-Lex™ Finishing and Polishing Discs (3M), ko izmanto konturēšanai un apstrādei, un gumijas pulēšanas līdzekļus TWIST DIA™ for Composite (Kuraray Noritake Dental Inc.), kas bez piepūles rada patīkamu, dabisku virsmas spīdumu. Pēc tam tiek izmantota kazas saru suka ar dimanta pulēšanas pastu (Diamond excel, FGM) un visbeidzot, es izmantoju kokvilnas pulieri kopā ar alumīnija oksīda pulēšanas pastu (Pasta Grigia II, anaxDENT). Tādā veidā iespējams izveidot spoguļveida virsmu. 

Emaljas kodināšana ar fosforskābes kodinātāju. 

Silikona matricas uzstādīšana.

CLEARFIL™ Universal Bond Quick uzklāšana. 

Situācija uzreiz pēc CLEARFIL MAJESTY™ ES Flow (Low) injekcijas, cietināšanas gaismā un silikona matricas noņemšanas.

Proksimālās korekcijas ar rotējošiem instrumentiem. 

Kādas ir plūstošās injekcijas metodes lielākās priekšrocības? 

Pacientiem un zobārstiem lielākās priekšrocības ir laika un naudas ietaupījums. Daudzi pacienti nevar atļauties keramikas venīrus, un viņi ir ārkārtīgi priecīgi, ka viņiem tiek piedāvāta kvalitatīva alternatīva, ko var uzlikt vienā apmeklējuma reizē. Procedūrai nav vajadzīga sagatavošana, un, ja nepieciešams, restaurācijas var viegli koriģēt vai mainīt krāsu, tādējādi ārstēšanai praktiski nav nekāda riska. Zobārsti parasti var sākt ārstēt pacientus pēc tam, kad viņi ir apmeklējuši tikai vienu kursu. Lai gan praktiski treniņi attīsta prasmes, arī pirmie rezultāti nereti jau ir diezgan iespaidīgi, tāpēc iesācējiem nav jāiegulda milzīgi ieguldījumi – ne laika ziņā, ne jaunos materiālos. Protams, jūs varat ieguldīt daudz laika apstrādes un pulēšanas procedūrā, taču esmu pārliecināts, ka jūs atradīsit pareizo līdzsvaru starp piepūli un rezultātu. 

Instrumentu komplekts plūstošās injekcijas metodei. 

Vai jums ir kāds ieteikums, kā sākt izmantot šo metodi? 

Pirmkārt, vēlos mudināt ikvienu izkāpt no savas komforta zonas un regulāri izmēģināt ko jaunu. Man sākt strādāt ar plūstošo injekcijas metodi bija revolucionārs pagrieziena punkts, un es nekad vairs negribētu strādāt bez tās. Pirms sākt lietot šo metodi, es noteikti apmeklētu kursus, kuros tiek apgūtas visas teorētiskās zināšanas, kas nepieciešamas veiksmīgam pirmajam gadījumam, un varbūt pat praktisko meistarklasi.

Mihals Jačevskis savas prezentācijas laikā Kuraray Noritake Dental stendā Ķelnē. 

Article by Dr. Michał Jaczewski

Resin composites are wonderful restorative materials: They allow for minimally invasive, defect oriented tooth preparation, may be modelled as desired, and can be modified and repaired whenever necessary. To achieve all of this, however, a strong and long-lasting bond is an absolute requirement. The bond needs to be established either between enamel and dentin on one side and the resin composite on the other, or between the existing and the newly applied composite material.

UNIVERSAL ADHESIVE

Committed to keeping clinical procedures as simple as possible, I use an 8th-generation bonding agent – CLEARFIL™ Universal Bond Quick (Kuraray Noritake Dental Inc.) in my dental office. Containing Rapid Bond Technology, it allows for a particularly easy and straightforward use without the need for extensive rubbing or long waiting times. At the same time, it bonds well to various substrates including enamel, dentin and resin composite as it contains the original MDP monomer.

Its composition and resulting versatility make CLEARFIL™ Universal Bond Quick the first choice for many indications including non- to minimally-invasive repair procedures. As it works extraordinarily well in situations where we want to bond to dentin, enamel or old composite (Fig.1), it is usually not necessary to remove the whole existing restoration that needs to be repaired or modified. Instead, preparation may be limited to the composite part, so that no additional tooth structure needs to be removed.

Fig. 1. CLEARFIL™ Universal Bond Quick establishes a strong bond to dentin, enamel or old composite.

CLINICAL PROTOCOL

Depending on the condition of the existing restoration surface, the repair protocol may be slightly different. The basic steps are as follows:

PROTOCOL 1: OXYGEN INHIBITION LAYER STILL ON THE SURFACE

- No surface treatment required, rinse with water in case of contamination with blood or saliva, followed by air-drying and (optionally) adhesive application

- Apply new layer of composite immediately

PROTOCOL 2: OXYGEN INHIBITION LAYER ALREADY REMOVED FROM THE COMPOSITE SURFACE

- Remove the composite around the defect and create a bevel at the cavity margin with rotating instruments

- Sandblast the surface with aluminium oxide particles

- Fresh composite surface: Clean the surface with KATANA™ Cleaner (Kuraray Noritake Dental Inc.) or etch with phosphoric acid etchant

- Composite surface older than two weeks: Etch with phosphoric acid etchant

- Apply the universal adhesive (which contains silane)

- Apply a new layer of composite

CLINICAL RECOMMENDATIONS

1. STAY IN THE COMPOSITE DURING PREPARATION

When an old composite restoration needs to be replaced – e.g. because the existing restoration shows discolouration or the patient asks for a brighter shade – it is possible to remove only a part of the composite and leave the rest in place to save the underlying healthy tooth structure. Accurate control over the amount of material removed and the amount of material left in place is offered by the use of UV light. Under UV light, the composite is perfectly visible (Fig. 2). Hence, a highly conservative structure removal is supported (Fig. 3).

Fig. 2. Controlling structure removal with UV light, which nicely reveals the old composite.

Fig. 3. Tooth preparation with rotating instruments.

2. INCREASE ADHESION BY SANDBLASTING

Creating a clean, micro-retentive composite surface ideal for bonding: This is the aim of sandblasting the affected composite area with aluminium oxide particles (Fig. 4). The particle size I prefer is 27 μm. Residual particles, may be removed with 37% orthophosphoric acid, which needs to be rinsed off thoroughly before air-drying the surface (Figs. 5a and 5b).

Fig. 4. Air-abrasion with 27 μm aluminium oxide particles.

Fig. 5a. Phosphoric acid etching. Adjacent teeth are protected with PTFE tape.

Fig. 5b. Thorough rinsing to remove the etchant from the surface.

3. USE A UNIVERSAL ADHESIVE THAT CONTAINS SILANE

When bonding to old composite, silanisation of the surface is recommended to increase the bond strength. On dentin, a separate silane shows no positive effect. Hence, it is recommended to apply a separate silane to the composite surface only, a challenging task in situations with a surface consisting of tooth structure and composite. As CLEARFIL™ Universal Bond Quick contains silane, the separate silane application step may be skipped, which clearly simplifies the procedure (Figs. 6a and 6b).

Fig. 6a. Application of CLEARFIL™ Universal Bond Quick to the prepared surface.

Fig. 6b. Solvent evaporation with a gentle stream of air.

4. IF IN DOUBT, USE A UNIVERSAL ADHESIVE DURING REPAIR PROCEDURES

Whenever detected during restoration, defects in the composite layer or air bubbles can be repaired or eliminated right away. As long as the oxygen inhibition layer is still present, another layer of composite may be applied immediately without any prior steps. However, if the surface has been contaminated by saliva or blood (Figs. 7a and 7b) or it is unclear whether we are bonding to dentin, enamel or composite, CLEARFIL™ Universal Bond Quick may be applied (Fig. 8). On top, a new layer of composite is placed to restore the defect (Fig. 9).

Fig. 7a. Composite surface with a defect near the margin with blood contaminating the affected area.

Fig. 7b. Composite surface with a defect near the margin after thorough rinsing and drying.

Fig. 8. Application of the universal adhesive.

Fig. 9. Application of composite material to restore the defect.

5. IF AVAILABLE, PLACE A SILICONE INDEX TO SIMPLIFY ANATOMICAL SHAPING

If the defect is small, it is possible to apply the flowable composite directly and remove the excesses (Fig. 10). The obtaining of a natural shape and smooth transition between old and new composite, however, is simplified by the use of a silicone index or matrix (Fig. 11), which might still be present from the original restoration procedure. A possible outcome of this type of repair is shown in Figure 12; both images were taken prior to finishing and polishing.

Fig. 10. Flowable composite spreading and excess removal.

Fig. 11. Silicone index placed over the teeth including the tooth with the defect.

Fig. 12. Outcome of the flowable injection procedure.

CONCLUSION

Elimination of bubbles or defects in a freshly created restoration, changes in the colour of an existing filling or a shape correction due to wear processes: Modifying composite restorations can be easy – provided that appropriate materials and techniques are used. One of the key elements on the path to success is the selection of a suitable adhesive system, preferably a universal single-bottle adhesive like CLEARFIL™ Universal Bond Quick, which allows for streamlined procedures and supports excellent outcomes. By respecting the provided tips, it is possible to create the desired outcomes in a minimally invasive, straightforward way, laying the foundation for long-lasting aesthetics and function.

Dentist:

MICHAŁ JACZEWSKI

Michał Jaczewski graduated from Wroclaw Medical University in 2006 and today runs his private practice in the city of Legnica, Poland. He specializes in minimally invasive dentistry and digital dentistry and is the founder of the Biofunctional School of Occlusion. Here he lectures and runs workshops with focus on full comprehensive patient treatments.

Leaving work at work, unplugging your mind from the dental office is not rocket science - provided that high-quality dental materials are used. Ideally, they are well-adapted to operator, case, and patient-specific needs. When it comes to restoring cavities with composite, Kuraray Noritake Dental Inc. has got the right products for any dental professional.

The CLEARFIL MAJESTY ES family of dental composites is composed of different product lines designed to meet specific needs. Altogether, the line-up offers a solution for every technique and handling preference, clinical situation and patient requirement.

UNIVERSAL SOLUTION FOR UTMOST SIMPLICITY

When utmost simplicity is desired, a highly innovative universal solution such as CLEARFIL MAJESTY ES-2 Universal is an excellent choice. This paste-type composite system includes only four shades: Universal, Universal Light, Universal Dark, and Universal White.

The Universal shade has the highest translucency and is, therefore, most suitable in cases where several cavity walls are still present, such as in Class I or II cavities and the cervical area. In cavities where light easily passes through, the lower-translucency variants Universal Light (for teeth with shades up to A3) and Universal Dark (for teeth darker than A3) are the best options. Universal White is the go-to solution for young patients and whitened teeth. Consequently, there is usually no need for a shade guide, and the optical properties allow application without an opaquer or blocker in most of cases. Both features greatly simplify the clinical procedure.

CLASSIC AND PREMIUM OPTIONS FOR SINGLE- AND DUAL-SHADE LAYERING

Clinicians who prefer classical single-shade layering according to a shade guide and a greater number of shades available may prefer CLEARFIL MAJESTY ES-2 Classic. With a line-up of 18 shades, it supports straightforward procedures and leads to aesthetic results.

Whenever the aesthetic needs are very high, such as in the context of restoring a large cavity in the aesthetic anterior region, CLEARFIL MAJESTY ES-2 Premium may be the best option. Designed for simplified multi-shade layering, it comes with fixed shade combinations of dentin and enamel opacity, that greatly support predictable outcomes.

MECHANICAL PROPERTIES

All the CLEARFIL MAJESTY ES paste-type composite systems offer a well-balanced viscosity and excellent mechanical properties, including

• a high flexural strength of 118 MPa
• a filler load of 78 wt%
• a compressive strength of 347 MPa
• a low volumetric shrinkage of 1.9 %
• a curing depth of 2.0 mm and
• a long working time under ambient light of 4.5 minutes
  
  

VERSATILITY POWERHOUSE IN THREE VISCOSITIES>

A flowable composite completes the portfolio. As the ideal level of viscosity depends on individual preferences and on the specific indication, CLEARFIL MAJESTY ES Flow comes in three different flowabilities: high, low and super low.

They have:

• a high flexural strength of 145, 151 and 152 MPa, respectively
• a filler load of 71, 75 and 78 wt%, respectively
• a compressive strength of 358, 373 and 374 MPa, respectively and
• a working time under ambient light of 100 seconds.

In addition, they are well-received for their easy application, fast polishing and high polish retention. All these features make the product a true versatility powerhouse. Moreover, it is offered in an innovative syringe designed for bubble-free application of the desired amount of composite and easy modelling.

THE IDEAL PORTFOLIO FOR PEACE OF MIND

The CLEARFIL MAJESTY ES portfolio offers highly suitable products for many clinical situations, demands and treatment techniques. As they support predictable outcomes and long-lasting success, using them gives dental practitioners the peace of mind needed to leave work at work and truly enjoy their free time—in the evening at home, on weekends or on holiday.

For more information about Kuraray Noritake Dental Inc.’s composite solutions visit the website.

Article by Dr. Michał Jaczewski

When working with composite, one of the most important aspects is to understand the mechanisms of adhesion. Choosing the right composite is one thing, but choosing a suitable bonding system and using it correctly is an equally important aspect affecting the long-term performance of a direct restoration.

There are many bonding products on the market - two-bottle (primer and bond) but also single-bottle systems. For anyone trying to select an ideal adhesive for a specific clinical case, the sheer number of available products can be challenging. The temptation to use them all, in slightly different ways, has the potential to create errors. In my dental practice, I am committed to simplifying procedures.

This is why I started looking for a bonding system that would offer a sense of security in terms of adhesion, but also ease of use in different clinical situations. I have opted for the 8^th-generation bonding agent with the desired features - CLEARFIL™ Universal Bond Quick (Kuraray Noritake Dental Inc.). The single-bottle universal adhesive is ideal for a broad variety of bonding procedures carried out in the dental office.

IMPRESSIVE FEATURES

CLEARFIL™ Universal Bond Quick can be used in the total-etch as well as the selective enamel etching technique in combination with an etching gel such as K-ETCHANT Syringe (Kuraray Noritake Dental Inc.). It is also a self-etching adhesive. Used in combination with the dual-cure build-up material CLEARFIL™ DC CORE PLUS or the dual-cure universal resin cement PANAVIA™ SA Cement Universal (both Kuraray Noritake Dental Inc.), it is also an ideal choice for cementation in the root canal and for cementing inlays or crowns made of a variety of different restorative materials – from metal to zirconia or lithium disilicate. Efficient clinical procedures are supported by the incorporated Rapid Bond Technology, which eliminates the need for extensive rubbing or waiting for the adhesive to penetrate the substrate and the solvent to evaporate. Among the key components of this technology are hydrophilic amide monomers, which allow the adhesive solution to penetrate moist dentin extraordinarily quickly, while also having a high curing ability. In addition, the original MDP monomer is included in the formulation. Together with the amide monomers, it provides for a high bond strength to enamel and dentin – achievable in a simple procedure of application, air-drying and light-curing.

The described properties turn CLEARFIL™ Universal Bond Quick into one of the most versatile and easy-to-use adhesive bonding solutions in the dental office. Operator sensitivity is low, as is its technique sensitivity, since the three-step procedure is always the same. The following case examples illustrate its use in the context of different repair procedures.

REPAIR OF COMPOSITE RESTORATIONS

One of the major benefits of using composite as a restorative material lies in the fact that it may be modified and repaired at any time. Regardless of whether an air bubble is detected on the surface, the shade needs to be adjusted, a fracture occurs or materials need to be added as a result of wear, modification or repair is easily accomplished without needing to sacrifice additional amounts of healthy tooth structure. Whenever a silicone index has been produced for the initial treatment and is still available, and the user knows which composite has been utilized for the original restoration, the Flowable Injection Technique may be selected as a particularly easy and efficient way of repairing a restoration. However the recommended protocol is slightly different depending on the state of the restoration surface.

CASE EXAMPLE 1: IMMEDIATE REPAIR PROCEDURE

When a restoration has been damaged or an air bubble has appeared during injection of a flowable composite, the procedure is slightly different. In this case, the oxygen inhibition layer is usually still present on the surface of the restoration. Therefore, it is possible to simply apply an additional portion of composite (Figs. 1a to 1d). Even after contamination of the composite surface with water, saliva or blood, this measure is possible. The surface merely needs to be rinsed thoroughly and dried before applying the new portion of composite. For maximum safety, a universal adhesive may be used as well.

Fig. 1a. Repair procedure applicable for defect within a composite restoration whenever the oxygen inhibition layer has not yet been removed: Air bubble detected in the interproximal region.

Fig. 1b. Application of a new portion of composite after rinsing and drying. The adjacent surface is protected with PTFE tape.

Fig. 1c. Repositioned silicone index used to give the restoration the originally planned shape.

Fig. 1d. Final restoration.

CASE EXAMPLE 2: REPAIR PROCEDURE AFTER POLISHING

If a similar defect is detected during finishing and polishing, i.e. when the oxygen inhibition layer has already been removed (Fig. 2), a roughening of the surface is strictly necessary. With a bevelled preparation of the area with the air bubble, optimal conditions are created for another layer of composite that blends in well with the surrounding material (Fig. 3). After bevelling, the surface needs to be sandblasted and cleaned either with KATANA™ Cleaner (Kuraray Noritake Dental Inc.) (Fig. 4a) or with 37 % orthophosphoric acid (Fig. 4b). After thorough rinsing and drying, an additional portion of composite may be applied to the surface (Figs. 5a to 5c). As the defect is small, the composite may be applied instead of injected and the silicone index repositioned afterwards.

Fig. 2. Void on the surface, detected during finishing.

Fig. 3.  Removed void and bevelled area around the defect.

Fig. 4a. Option 1: Cleaning of the surface with KATANA™ Cleaner.

Fig. 4b. Option 2: Etching with K-ETCHANT Syringe.

Fig. 5a. Application of composite (CLEARFIL MAJESTY™ ES Flow Low).

Fig. 5b. Repositioning of the original silicone index to obtain the desired shape.

Fig. 5c. Final restoration with a nice blend-in of the different layers of composite.

CASE EXAMPLE 3: REPAIR PROCEDURE AFTER TWO OR MORE WEEKS

For damaged restorations which have been in place for more than two weeks, an ideal composite-composite interface needs to be created by bevelling and roughening of the surface. A perfect example is presented in Figure 6. The most important step influencing the success of the procedure is proper preparation of the composite surface. To lay the foundation for a strong bond between the new and the old composite as well as for aesthetic outcomes, a bevel needs to be created (Figs 7a and 7b) to facilitate a smooth transition between the two layers. Once the bevel is completed, the surface should be sandblasted with alumina particles sized 27 μm (Fig. 8). The following recommended steps are etching of the composite with 37 % orthophosphoric acid (Fig. 9) and finally application of CLEARFIL™ Universal Bond Quick (Fig. 10). As the universal adhesive contains a silane coupling agent, separate silane application is not necessary. Instead, the new layer of composite may be applied immediately e.g. using the flowable injection technique with an existing matrix (Fig. 11).

Fig. 6. Fractured anterior composite restoration benefitting hugely from repair – the remaining composite is in a great state regarding colour and shape.

Fig. 7a.  Bevelling with dedicated instruments.

Fig. 7b.  Ideal bevel created to provide for a strong bond and great optical blend-in.

Fig. 8. Sandblasting of the surface with alumina particles.

Fig. 9.  Phosphoric acid etching.

Fig. 10. Application of the universal adhesive.

Fig. 11. Composite applied using the flowable injection technique.

Fig. 12. Treatment outcome.

CONCLUSION

The three described repair protocols are straightforward and work well – provided that a strong bond is established at the composite-composite interface. The way it is established may be slightly different depending on whether the oxygen inhibition layer is still present or has already been removed. Using a universal adhesive like CLEARFIL™ Universal Bond Quick, the procedure is simplified owing to elimination of steps such as the separate application of silane.

Dentist:

MICHAŁ JACZEWSKI

Michał Jaczewski graduated from Wroclaw Medical University in 2006 and today runs his private practice in the city of Legnica, Poland. He specializes in minimally invasive dentistry and digital dentistry and is the founder of the Biofunctional School of Occlusion. Here he lectures and runs workshops with focus on full comprehensive patient treatments.

DELICATE BALANCE BETWEEN COSTS AND AESTHETICS IN DENTAL LAB

When you are a lab owner striving to achieve high-end results using modern digital techniques, the initial investment in CAD/CAM technology is significant, followed by ongoing costs for expendable items such as milling tools and blanks. That cost can be reduced by selecting universal, high-quality materials.

Undoubtedly, zirconia stands out as one of the most popular materials on the market. From an inventory perspective, however, lab owners often find themselves purchasing multiple discs of the same shade and thickness. The reason is that they need to meet all requirements for strength and aesthetics in different settings – enabling them to cover all kinds of restorations and deliver excellent patient outcomes.

UNIVERSAL SOLUTION FOR DENTAL LABS

At Kuraray Noritake Dental Inc., we take pride in not only developing the first-ever multilayer zirconia, KATANA™ Zirconia ML, but also in our commitment to delivering the highest quality materials that we can.

KATANA™ Zirconia YML, our latest addition to the KATANA™ Zirconia line-up, exemplifies this dedication and offers universal applicability. The universal feature is based on the fact that KATANA™ Zirconia YML disc not only offers colour gradation, but also impressive flexural strength and translucency gradation, with maximum values of up to 1,100 MPa and 49 % translucency, respectively.

INHOUSE PRODUCTION - THE PATH TO HIGH QUALITY ZIRCONIA DISC

Like all our zirconia offerings, KATANA™ Zirconia YML begins its journey to the dental lab in our Japanese facility where raw zirconia powder undergoes special treatment process before the addition of essential components.

Once the material has undergone this thorough initial stage, it progresses to the pressing and pre-sintering phase to form the disc. Every detail is carefully calculated, managed and controlled. This phase of the process takes several days, underscoring our goal to achieve the most aesthetic product.

HIGH-SPEED SINTERING PROGRAM: 54 MINUTES

The unique powder formulation and refinement process, as well as the pressing and pre-sintering technique, is the key to allow our customers to realize restorations of up to three-unit bridges without any compromise in terms of aesthetics or mechanical properties using the 54-minute high-speed sintering* process.

This high quality, lengthy production process results in an exceptionally dense material, which once sintered, goes on to deliver a high strength, high aesthetic final restoration.

HIGH PRECISION SHRINKAGE AND STABLE CTE VALUES FOR EXCEPTIONAL FIT

Outstanding deformation stability during the sintering procedure, contributes to the stability during the final sintering process in the dental laboratory, providing for an exceptional fit of large-span bridges and other restorations.

MULTI-LAYERED STRUCTURE AND EASE OF POSITIONING OF RESTORATIONS IN THE BLANK

To enhance aesthetic qualities, all KATANA™ Zirconia YML discs are designed using ratios rather than fixed measurements of different layers in the multi-layered structure. This means that regardless of the disc's thickness, there is always a consistent ratio of 35 % of raw material that constitutes the translucent enamel zone. Hence, discs with an increased height, which are typically used for the production of larger restorations, will always offer sufficient space in the enamel zone, while smaller discs are optimized for smaller restorations.

ONE DISC. ALL INDICATIONS.

These qualities empower dental lab owners to deliver a wide range of restorations. The material is suitable for single crowns to full-arch structures, for full-contour designs to conventional frameworks, using a single material without compromising on aesthetics: KATANA™ Zirconia YML. For finishing, we offer a well-aligned portfolio of solutions designed for internal and external staining, micro-layering and full layering.

EXPLORE KATANA™ Zirconia YML: WEALTH OF RESOURCES, CLINICAL CASES AND FAQS

Visit our website to discover more about KATANA™ Zirconia YML. You will find useful materials such as brochure, technical guide, in-depth technical information.

Would you like to see the material in action – browse the blog section of our website that offers a variety of clinical cases and articles by world-renowned experts showcasing and proving the versatility and aesthetics of KATANA™ Zirconia YML.

*The material is removed from the furnace at 800°C. A furnace with a configurable KATANA™ Zirconia YML firing program is required.

FLOWABLE INJECTION AND STAMP TECHNIQUE: RESTORING TEETH IN THE POSTERIOR REGION

Restoring the occlusal surface of posterior teeth while preserving the natural morphology and re-establishing correct occlusal contacts has always been challenging for dental practitioners. Free-hand layering requires knowledge of tooth anatomy, composite handling skills and experience. When the occlusal surface of a tooth is damaged at the start of treatment (as is usually the case in teeth with large MOD cavities) or an increase of the vertical dimension of occlusion is planned (e.g. in severely worn teeth), the use of the flowable injection technique may be a suitable alternative. It truly speeds up and facilitates the process of building up the restoration to a natural shape, but requires thorough planning and preparation. In cases with an intact occlusal surface, the stamp technique might be the first choice.

FLOWABLE INJECTION TECHNIQUE: GENERAL CONSIDERATIONS

It is up to the user how exactly the restorations, to be built up by flowable injection, are planned and how the plan is implemented: One can either opt for a conventional wax-up or make use of digital tools in the planning phase. Dedicated design software offers the benefit of facilitating the creation of a natural shape and morphology of the desired restoration and allows for the establishing of an ideal occlusal relationship. Once the wax-up is ready, it needs to be transferred into the patient’s mouth. This is accomplished via a printed or classical model with wax-up, which forms the basis for the production of a matrix or silicon index. This index is then used intraorally for the injection of the flowable composite. To enable proper light curing through the index, the index material should be as transparent as possible.

AREA-SPECIFIC CONSIDERATIONS

In the posterior area, an index made of two different materials – a soft inner silicon structure and a hard outer shell – may be advisable. Due to its higher dimensional stability compared to a soft silicon index, it is possible to put pressure on it for proper adaptation to the isolated teeth and soft tissue without the risk of altering the shape of the tooth. Figure 1 shows such an index on and next to a printed model. It consists of a hard shell made of acrylic and a soft inner structure made of a transparent silicone material (e.g. EXACLEAR™, GC). For production, a high-capacity hydraulic pressure curing unit designed for use with self-curing resins (Aquapres™, Lang Dental) has proven its worth: It ensures a highly accurate reproduction of the (digital) wax-up.

Fig. 1. Printed model and silicone index.

Reconstruction of posterior teeth with the flowable injection technique requires prior removal of all carious lesions and reconstruction of the proximal surfaces to restore the contact points. Hence, the injected composite serves the exclusive purpose of restoring the occlusal surface. When several teeth are treated, a two-step procedure with an alternating technique is recommended to provide for proper separation of the teeth. Blocking the proximal surfaces below the contact point with PTFE tape will reduce the amount of excess material in these areas and make it easier to clean and prepare the proximal surfaces after flowable injection. Proximal and deeper occlusal lesions should be restored with the aid of a matrix, wedge and ring.

CLINICAL PROTOCOL

A possible clinical protocol is illustrated in Figures 2 to 5: After caries excavation and tooth preparation, sectional matrices, wedges and rings were placed to allow for simultaneous treatment of the mesial and occlusal cavities. Following etching and application of the universal adhesive CLEARFIL™ Universal Bond Quick (Kuraray Noritake Dental Inc.), the cavities were restored with CLEARFIL MAJESTY™ ES Flow Super Low in the shade A1 and CLEARFIL MAJESTY™ ES-2 Universal in the shade U. The distal cavity of the first molar was filled in the last step of the free-hand modeling procedure. In order to restore the occlusal surfaces in their original vertical dimension, every second tooth was isolated with rubber dam and the exposed molar etched (total-etch technique with K-ETCHANT Syringe, Kuraray Noritake Dental Inc.). the alternating index was positioned with some pressure and the flowable composite (CLEARFIL MAJESTY™ ES Flow Super Low) injected. Once light curing was completed, it was possible to remove the index, chip off the excess and finish and polish the restoration before repeating the procedure for the adjacent molar.

Fig. 2. Restoration of two molars: Teeth preparation and caries excavation.

Fig. 3. Restoration of two molars: Filling of the proximal and occlusal cavities.

Fig. 4.  Restoration of two molars: Re-establishing the occlusion with the aid of the flowable injection technique.

Fig. 5. Alternating approach: Restoration of the second molar by injecting flowable composite.

DISCUSSION

The use of the flowable injection technique allows for rapid restoration of teeth and the establishment of precise occlusal contacts. This reduces the time spend on occlusal surface modelling and minimizes the risk for prolonged treatment due to a repeated need for occlusal adjustments. In addition to saving time, it is possible with this technique to restore a greater number of teeth in a single appointment. The aesthetics of this type of restoration may be somewhat limited: A skilled practitioner is able to achieve better aesthetic results on the occlusal surface. However, with a detailed wax-up and high-quality model great outcomes can be obtained. The surface quality of printed models can be increased by adjusting the printing parameters including the layer height (Fig. 6). The use of a hydraulic pressure curing unit for silicone index production further increases the quality of the occlusal surface.

When planned and implemented correctly, the established occlusal surface and contacts reflect the natural anatomy without the need for adjustments (Fig. 7). Especially when restoring an entire quadrant, it is possible to increase the efficiency by opting for the flowable injection technique. Doing so reduces the number of appointments and the chair time decisively (Fig. 8).

STAMP TECHNIQUE: CONSIDERATIONS

If the occlusal surface of the tooth is intact, a wax-up may not be necessary. In this case, the better strategy is to duplicate what is still available before initiating treatment. A flowable composite or liquid rubber dam can be used for this purpose. It is important to coat the tooth surface with glycerin gel before applying the material. This will facilitate separation of the stamp from the tooth. It is always advisable to create a stamp that covers not only the details that need to be recorded and duplicated, but is extended over the cusps. This offers better stability in the restoration phase.

CLINICAL PROTOCOL

Figures 9 to 11 illustrate a possible clinical procedure. In this case, a molar with an occlusal carious lesion needed to be restored. The tooth surface was cleaned and a thin layer of glycerin gel applied, followed by a thick layer of liquid rubber dam, which covered the entire occlusal surface. Then, a micro applicator was immersed into the material and the stamp cured. After preparation, etching and application of the bonding system, the cavity was restored with flowable composite (CLEARFIL MAJESTY™ ES Flow Super Low in the shade A2). When the cavity is larger and depending on personal preferences, a paste-type composite (CLEARFIL MAJESTY™ ES-2 Universal) may also be used. Prior to light curing of the composite, the occlusal surface was covered with PTFE tape and the stamp pressed onto it. After firm pressing, the tape and excess material were removed and the restoration polymerized. This restoration faithfully reproduces the occlusal surface and did not require any occlusal adjustments.

Fig. 6. Stamp production with liquid rubber dam.

Fig. 7. The stamp.

Fig. 8. Restoration procedure: From preparation to bonding.

Fig. 9. Restoration procedure: Filling with flowable composite.

Fig. 10. Restoration procedure: Duplication the original occlusal surface with the stamp.

Fig. 11. Tooth before and after treatment using the stamp technique.

CONCLUSION

Techniques that add simplicity and efficiency to clinical procedures are always welcome in the busy practice environment. Depending on the information available at the start of treatment and the number of teeth to be restored, the flowable injection or the stamp technique may be an ideal choice. They are easily implemented and speed up the clinical procedure, but most importantly support predictable outcomes. This saves time in the finishing phase and minimized the risk of repeated adjustments, hence protecting everyone involved from additional appointments and frustration. Especially for practitioners with limited routine in free-hand modelling and for those with maximum patient comfort in mind, both techniques are worth being integrated in their clinical procedures.

Dentist:

MICHAL JACZEWSKI

Michał Jaczewski graduated from Wroclaw Medical University in 2006 and today runs his private practice in the city of Legnica, Poland. He specializes in minimally invasive dentistry and digital dentistry and is the founder of the Biofunctional School of Occlusion. Here he lectures and runs workshops with focus on full comprehensive patient treatments.

Augstas kvalitātes protezēšanas nozīme

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

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

Cirkonija restaurācijas – mūsdienīgs un estētisks zobārstniecības risinājums

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

Zobu cirkonija kvalitātes atšķirības

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

Bieži sastopamās problēmas, ko izraisa zemas kvalitātes cirkonija oksīds

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

Overview of potential problems and clinical consequences for patients

Zobu cirkonija sertifikācija un standartizācija

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

Kā izvairīties no zemas kvalitātes zobu cirkonija restaurāciju ievietošanas pacienta mutē

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

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

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

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

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

Ilgtermiņa ietekme pacientiem, izmantojot sertificētas cirkonija restaurācijas

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

Izpētiet cirkonija iespējas un izvēlieties produktus no sertificētiem ražotājiem

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

PROF. LORENCO BREŠI (LORENZO BRESCHI) RAKSTS

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

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

Pašcementējošā fiksācija: daudzām indikācijām

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

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

Adhezīva līmēšana: sarežģītām situācijām

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

Selektīva adhezīva cementēšana: īsiem noslīpētiem zobiem un subgingivālajām malām

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

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

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

Rekomendētās darbības selektīvajai adhezīva līmēšanai

1. attēls. Zoba sagatavošana

2. attēls. Selektiva emaljas kodinašana ar fosforskabes kodinataju

3. attēls. Universala adheziva uzklašana un žavešana ar gaisu

4. attēls. Krona novietošana pec sveku cementa uzklašanas kroni

5. attēls. Cietinašana

6. attēls. Lieka daudzuma noemšana un galeja cietinašana
gaisma

7. attēls. Arstešanas rezultats pec viena gada

Selektīvās adhezīva cementēšanas priekšrocības

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

Secinājumi

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

Dentist:

LORENZO BRESCHI

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

Atsauces

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

Unlock the power of zirconia: perfect for adhesive cementation, the ideal material for a wide range of indications, and essential in minimal invasive dentistry. Time to trust zirconia bonding!

This article demystifies zirconia bonding, providing clear, practical steps to ensure long-term functionality and patient satisfaction, all based on scientific research. Master the three adhesion pillars: mechanical retention, chemical activation, and wetting capacity. Discover how to successfully prepare zirconia surfaces, avoid pitfalls like misapplying silica coating and silane, and choose proven bonding systems for optimal results. Optimise retention even with minimal tooth preparation and achieve reliable zirconia restorations. Say goodbye to doubts and hello to successful zirconia bonding!

Factors influencing retention

Loss of retention due to de-cementation or debonding is a common cause of dental prostheses' failure.  First, let’s have a look at how to cope with the three main factors significantly influencing retention: tooth preparation, restoration pre-treatment, and cement type/bonding.

Tooth preparation

The abutment tooth's height, angle, and surface texture must be considered to achieve sufficient retention and resistance from the preparation. The retention form counteracts tensile stresses, whereas the resistance counteracts shear stresses ⁴. With the proper preparation, a restoration resists dislodgement and subsequent loss.

Full coverage restorations

To achieve sufficient retention and resistance for full-coverage crowns, the tooth abutment should be at least 4 mm high, and the convergence angle should range from 6 to 12 degrees with a maximum of 15 degrees ^{1, 5-8}.

Source; Conventional cementation or adhesive luting - A guideline, Dr. A. Elsayed, Prof. Dr Florian Beuer 

Adhering to the tooth preparation guidelines is crucial for full-coverage restorations (e.g., crowns, and FDPs). These practical guidelines are designed to achieve the required retention and resistance to make conventional luting possible. However, optimal retention and resistance are, in reality, hard to achieve. An unwanted amount of sound tooth substance often should be removed to achieve a highly retentive preparation. Moreover, several studies^2,3 show that, in daily practice, the preparation angle often exceeds 15 degrees.

Minimal-invasive restorations

Minimal-invasive restorations, such as single retainer FDPs, veneers, table-tops and inlay-retained FDPs, are based on a non- or low-retentive preparation form. In this case, retention shifts from (macro-)mechanical to micro-mechanical and chemical, necessitating the use of adhesive techniques ^9-11. Even though the preparations for minimal-invasive restorations largely lack mechanical retention, the long-term success of these types of restorations is well-documented when using a suitable resin cement (e.g. PANAVIA™, Kuraray Noritake Dental, Japan), including a proper pre-treatment and bonding procedure ^{10, 11}.

In high-retentive situations, conventional luting is acceptable for full-coverage restorations*. In all other cases, choosing a resin cement is a better solution. With proper tooth preparation (e.g., shaping, (self-)etching, abrasion) and the right adhesive resin cement system, a non-retentive preparation form provides a reliable basis using mainly chemical retention and micro-mechanical retention instead of macro-mechanical retention.

*Please review the articles available regarding the debate over whether to use a conventional cementation procedure, adhesive cementing, or selective adhesive luting

Restoration pre-treatment

Zirconia is densely sintered and does not contain a glass phase. Therefore, it cannot be etched with hydrofluoric acid to create a micro-retentive etching pattern. In addition, silanes cannot effectively promote zirconia bonding. Several studies have shown that air abrasion with 50-µm alumina at a reduced pressure of 0.5 bar (0.05 MPa; 7 psi) will create a sufficient micro-retentive pattern¹² and greatly enhances the wetting capacity.

In addition to air abrasion, chemical coupling agents such as bifunctional phosphate resin monomers are used on air-abraded zirconia. Bonding with phosphate monomer-containing adhesive resin systems gives very reliable results^27,28. The use of phosphate monomer-based resin cement systems (e.g., Panavia [Kuraray Noritake Dental, Tokyo, Japan]) and/or phosphate monomer primers, such as CLEARFIL CERAMIC Primer Plus (Kuraray Noritake Dental, Tokyo, Japan)  on freshly air-abraded zirconia, offer the most reliable bonding methods today ^13,27,28. We therefor consider MDP-based composite resin cements the material choice for our bonding procedure. However, it must be stressed that contamination of the air-abraded zirconia with saliva, phosphoric acid or other contaminants will limit the formation of chemical bonds and, therefore, must be avoided.

Avoiding contamination

For optimal moisture control, absolute isolation of the working field is crucial. Minimising  the risk of contamination, avoiding exposure to oral fluids. Before restoration placement, a thorough cleaning of the abutment tooth is essential. Following trial placement, a meticulous recleaning step is recommended to remove any potential introduced contamination. KATANA Cleaner (Kuraray Noritake Dental, Tokyo, Japan) is an ideal choice due to its unique properties. Its slightly acidic pH of 4.5 allows for effective cleaning intraoral and extraoral adhesion surfaces. Additionally, the incorporation of MDP monomer technology makes it highly efficient. The MDP salt in this product effectively bonds with contaminants, breaks them down and results in easy removal by water rinsing.

Cement type/bonding

After pre-treatment of surfaces to optimise the , it is important to understand that the properties of highly translucent zirconia differ highly from those of earlier generation zirconia. Early-generation zirconium oxides, including 3 mol% yttrium oxide (3Y-TZP), are high in strength and low in translucency. With the increase in yttria, creating 4-5 mol% yttria, or higher, zirconium oxides, the number of cubic crystals increases, resulting in higher translucency but leading to a reduction in strength. Therefore, attention must be paid to zirconia type, material thickness, restoration type, and application area. These factors may influence the choice of cement based on the adhesive properties demanded for lasting restorations and high aesthetic outcomes.

PANAVIA™ V5

For a resin cement system to deliver a strong bond, it is not always enough to have it contain an appropriate adhesive monomer. It is necessary for that adhesive monomer to be polymerised effectively under different circumstances. The PANAVIA™ V5 system contains an innovative “ternary catalytic system” consisting of a highly stable peroxide, a non-amine reducing agent* and a highly active polymerisation accelerator. Since this catalytic system is amine-free, the hardened cement has unsurpassed colour stability. In addition, the highly active polymerisation accelerator, one of the components in PANAVIA™ V5 Tooth Primer, is not only an excellent reducer that promotes polymerisation effectively, but it is also capable of coexisting with the (in this product) acidic MDP. This makes it possible to create a single-bottle self-etching primer. This accelerator is also responsible for the so-called touch-cure reaction when it comes into contact with the paste. Resulting in the sealing of the dentin interface and, at the same time, allowing the paste to set even in situations where light curing is limited.

*PANAVIA™ V5 Tooth Primer applied and left for 20 seconds, followed by air drying.

The second primer in the PANAVIA V5 system is CLEARFIL™ CERAMIC PRIMER PLUS, which incorporates Kuraray Noritake Dental’s original MDP and a silane. This product is used to prime zirconia but is also an excellent choice for priming silica-based ceramics, composites, and metals.

CLEARFIL™ CERAMIC PRIMER PLUS, which contains the original MDP, applied and dried.

The PANAVIA™ V5 full adhesive resin cement system consists of all three above-mentioned components, always used in the same way, independent of the material, for a straightforward procedure to ensure reliable bonding. The PANAVIA^TM V5 systems offer try-in pastes to visualise the final results before final cementing and confirm the appropriate shade of the resin cement to be used.

PANAVIA™ VENEER LC

Offering a flexible workflow and high bondability of thin, translucent restorations like veneers but also inlays and onlays, PANAVIA™ Veneer LC was designed. It is a light-curing resin cement system allowing a long working time of 200 seconds under ambient light*. This allows multiple veneers to be placed simultaneously without racing against the setting. The final light-curing can be started anytime after positioning the provisions. The PANAVIA™ Veneer LC cementing system includes PANAVIA™ Tooth Primer and CLEARFIL CERAMIC PRIMER Plus as primers to chemically interact with the adhesive surfaces.

PANAVIA™ Veneer LC Paste applied and the laminate veneer seated. In this case six veneers were simultaneously placed during one session.

Unpolymerized excess paste removed with a brush. PANAVIA™ Veneer LC Paste is a light-cured type rein cement, designed to provide sufficient working time.

This photo shows the results after the final light curing. Since the excess cement was easily removed, there were almost no cement residues.

PANAVIA™ SA CEMENT Universal

Still, clinicians seek efficiency and effectiveness in everyday practice by using a straightforward but durable resin cement solution. PANAVIA™ SA Cement Universal is developed to offer this ease-of-use property without losing focus on bonding properties.  PANAVIA™ SA Cement Universal is developed with the original MDP monomer in the hydrophilic paste compartment, allowing for chemical reactiveness with zirconia and tooth structure. The other compartment contains the hydrophobic paste, to which a unique silane coupling agent, LCSi monomer, is added, which allows the cement to deliver a strong and durable chemical bond to silica-based materials like porcelain, lithium disilicate and composite resin*. Furthermore, PANAVIA™ SA Cement Universal is less moisture sensitive than full adhesive resin cement systems. This also makes it the ideal cement in situations where rubberdam isolation is difficult.

*The product is available in both auto mix and hand mix options.

*Old PFM bridge (shown here) removed, and existing preparations modified to accommodate a 3-unit KATANA™ Zirconia bridge. The upper right canine was prepared to receive a single-unit KATANA™ crown.

Before

After. Seating & Final Smile. PANAVIA™ SA Cement Universal and CLEARFIL™ Universal Bond Quick were used for cementation and bonding. “I love the ease of use and clean-up with PANAVIA™ SA Cement Universal, and its MDP monomer creates a strong chemical bond to the tooth structure and zirconia. CLEARFIL™ Universal Bond Quick has a quick technique without reducing bond strengths, releases fluoride and has a low film thickness. I simply rub CLEARFIL™ Universal Bond Quick into the tooth for a few seconds and air dry. There is no need to light-cure, since it cures very well with PANAVIA™ SA Cement Universal. The patient was very happy with the results. She loved that she no longer saw metal margins, and her smile was much more uniform and lifelike.” Dr. Kristine Aadland

*Images are a part of a case by Dr. Kristine Aadland; 3-Unit anterior maxillary

Bonding to zirconia in three steps

Over the last century, the popularity of highly translucent zirconia has skyrocketed due to its excellent properties and wide range of anterior and posterior clinical applications. Because zirconium oxide prostheses are, if processed correctly, antagonist-friendly and easy (and relatively inexpensive) to fabricate, the material keeps gaining popularity in dentistry.

Several steps need to be taken into account for reliable and durable bonding. Years of research on achieving high and long-term bond strength to zirconia have concluded into three practical steps, summarised as the APC concept¹³ as a reliable procedure guideline.

APC-Step A

Zirconia should be air-particle abraded (APC-Step A) with alumina or silica-coated alumina particles; the sandblasting or micro-etching procedure. Air abrasion with a chairside micro-etcher using aluminium oxide particles (size: up to 50 μm) at a low pressure of 0,5 bar (0.05 – 0.25 MPa) is sufficient.^14,18,25-27

APC-Step P

The subsequent step includes applying a special ceramic primer (APC-Step P), which typically contains specially designed adhesive phosphate monomers, onto the zirconia adhesive surfaces.^29,30 The MDP monomer has been shown to be particularly effective at bonding to metal oxides like zirconium oxide.

APC-Step C

Dual- or self-cure resin cement systems should be used to reach an adequate C=C conversion rate underneath the zirconia restoration since the lack of translucency in zirconia reduces light transmission.¹³ However, in cases where high-translucent zirconia (HTZr0₂) is used, the zirconia transmits light so that the shade of composite or resin cement might influence the final appearance of such restorations. It is, thereforebased on the individual situation and shade of the abutment tooth.

The APC zirconia-bonding concept is not limited to intra-oral situations and can also be applied in the laboratory for implant reconstructions that include cemented zirconia components.

Conclusion

Rapid developments in high-quality translucent zirconia have made the utility and reliability of adhesive cementing systems even more crucial. This applies to fully opaque restorations but also minimally invasive and ultra-translucent restorations of low thickness. In all cases, the longevity of the bonding and, thus, the provision directly affects patient  satisfaction. By taking into account the three primary parameters we have discussed in this article and following the predictable APC protocol, you will successfully realise durable bonded zirconia restorations from now on.

References

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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

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