429 Too Many Requests

Article by Dr. Adham Elsayed

Les ciments de résine adhésifs haute-performance sont souvent les facilitateurs des traitements prothétiques mini-invasifs. Lorsque le principal objectif est de conserver autant que possible la structure dentaire saine, on abandonne généralement les conceptions préparatoires qui offrent suffisamment de rétention macro-mécaniques pour les colles conventionnelles. Les conceptions retenues à la place doivent reposer sur une adhésion chimique solide et durable entre la structure dentaire et le matériau de restauration - une telle adhésion est réalisée avec succès grâce aux systèmes de ciment de résine adhésif modernes.

Un excellent exemple de conception de préparation et de restauration mini-invasive et non-rétentive est la prothèse dentaire fixe à adhésion résine et à attache unique (RBFDP), généralement fabriquée de nos jours à partir de zircone 3Y-TZP. Avec son unique cantilever collé à la surface orale et proximale de l’émail d’une dent adjacente, la structure dentaire saine à retirer est minimale voire nulle. La RBFDP est souvent utilisée pour remplacer une dent manquante congénitale – soit dans de nombreux cas une incisive maxillaire latérale – chez les jeunes patients au développement dentoalvéolaire incomplet et espaces édentés étroits qui ne permettent pas la pose d’un implant conventionnel1 (Fig. 1 et 2). D’autres facteurs faisant obstacle à la thérapie implantaire - comme un volume osseux insuffisant ou des racines anguleuses - ne constituent pas non plus un problème pour ce type de restauration. En outre, en comparaison avec la fermeture d’écart orthodontique, l’approche du traitement avec RBFDP est moins risquée étant donné qu’elle n’affecte pas la relation maxillaire verticale, ne gêne pas le guide canin et ne compromet pas l’esthétique2. Enfin, elle est beaucoup moins invasive que les FDP conventionnelles qui ne constituent pas, en général, une option de traitement pour les jeunes patients dans la zone antérieure. Le degré de satisfaction du patient et le taux de réussite de cette approche de traitement sont impressionnants3-7.

Figure 1-2 : Le remplacement des deux incisives maxillaires latérales manquantes congénitales par des RBFDP en zircone à attache unique après augmentation du tissu mou et correction marginale de la gencive.

Malgré les nombreux avantages et excellentes performances cliniques - le taux de survie d’une RBFDP en zircone à attache unique est de 98,2 % et le taux de réussite de 92,0 % après dix ans4 – beaucoup de praticiens dentaires privilégient encore des options de traitement alternatives. La raison pourrait en être un manque de confiance dans la force d’adhésion et la durabilité avec la zircone. Toutefois, cette adhésion peut être très solide et durable - à condition de respecter quelques règles.

COMMENT ÉTABLIR UNE FORTE ADHÉSION À LA STRUCTURE DENTAIRE

Afin de décider si une dent manquante peut être remplacée de manière réussie par une RBFDP en zircone à attache unique, la dent-pilier doit être examinée attentivement. Elle doit être vitale et largement libre de caries ou restaurations directes alors que la surface orale de l’émail doit être suffisamment large pour l’adhésion résine1. En outre, l’espace requis pour le positionnement d’une aile d’attache (épaisseur : environ 0,7 mm) doit être disponible étant donné qu’une conception sans contact est essentielle à la réussite de la restauration. Parmi les conceptions préparatoires décrites dans la littérature, on trouve uniquement une préparation de facette linguale et petite box proximale avec des éléments de rétention situés dans l’émail1 ou aucune préparation du tout7. Pour la pose de restauration, la dent-pilier est traitée comme d’habitude : après nettoyage, p.ex. avec une pâte prophylactique sans fluorure, un mordançage à l’acide phosphorique est appliqué à la surface d’adhésion, avant rinçage et séchage soigneux.

COMMENT ÉTABLIR UNE FORTE ADHÉSION À LA RESTAURATION

Le pré-traitement recommandé pour la surface d’adhésion de l’aile d’attache en zircone est une air-abrasion avec petites particules (50 μm) d’oxyde d’aluminium à basse pression (approx. 1 bar)8,9, suivie d’un nettoyage à ultrasons. La figure 3 (A-E) montre la séquence du traitement de surface des restaurations zircone. Pour un traitement à l’air-abrasion contrôlée, le marquage de la surface au crayon s’avère être une aide visuelle très utile. L’ensemble de la procédure d’air-abrasion devrait être réalisée après essai car la surface dentaire et la restauration sont généralement contaminées par contact avec de la salive et parfois du sang. Les protéines présentes dans la salive et le sang qui contaminent la surface d’adhésion sont ainsi éliminées de manière sûre et la modification de surface nécessaire pour établir une adhésion solide et durable au système de ciment de résine sélectionné est réalisée10.

FIGURE 3 : SÉQUENCE DU TRAITEMENT DE SURFACE DES RESTAURATIONS ZIRCONE

Figure 3A : Nettoyage de la restauration avant assemblage avec un nettoyeur à vapeur d’eau

Figure 3B : Marquage de la surface d’adhésion en tant qu’aide visuelle pour l’air-abrasion

Figure 3C : Air-abrasion avec particules Al2O3 de 50 μm à 1 bar de pression

Figure 3D : Application d’un apprêt contenant du 10-MDP

Figure 3E : Application du ciment de résine composite

QUEL SYSTÈME DE CIMENT DE RÉSINE CHOISIR

Ensuite, les composants du système de ciment de résine sont appliqués. Concernant la sélection du système, il est généralement recommandé d’utiliser un apprêt de restauration ou un ciment de résine contenant du 10 Methacryloyloxydecyl dihydrogen phosphate (10-MDP)11. Une liaison chimique de qualité peut ainsi être établie. PANAVIA™ 21 (Kuraray Noritake Dental Inc.) figure parmi les systèmes de ciment de résine utilisés dans les études cliniques à long terme disponibles4- 6. Lancé en 1993, ce ciment de résine adhésif à polymérisation anaerobie contient plusieurs technologies majeures comme le monomère MDP et la Touch Cure Technology que l’on retrouve dans PANAVIA™ V5, le système de pointe de la société avec son ciment de résine adhésif à double polymérisation et flacons multiples. Afin d’améliorer encore les performances d’adhésion de ce produit, l’équipe de développeurs a revu sa composition de base et actualisé puis combiné les technologies existantes avec des ingrédients entièrement nouveaux.

Même avec PANAVIA™ 21 qui a été introduit il y a 30 ans, des taux de réussite élevés ont été obtenus4-6. Les quelques défauts observés étaient principalement dus à des ébréchures de la céramique de facettage ou à un décollement. Parfois causé par des incidents traumatiques, le décollement n’a pas entraîné d’autres dommages et les restaurations ont été simplement recollées avec le même système et la même procédure de cimentation.

On pouvait s’attendre à ce que, avec sa formulation améliorée, PANAVIA™ V5 offre une adhésion encore plus solide et durable que les produits prédécesseurs, de sorte qu’il conviendrait encore mieux à des applicationsaussi exigeantes que les prothèses dentaires fixes à adhésion résine. Cette supposition a été confirmée dans une étude pilote7. Sans aucune préparation de la dent-pilier, mais une taille de surface d’adhésion définie à au moins 35 mm2, l’équipe de chercheurs a posé 24 bridges monolithiques en zircone à adhésion résine (à partir de KATANA™ Zirconia HT) pour remplacer des incisives latérales manquantes congénitales. Les côtés palataux des incisives centrales ont été nettoyés avec de la pâte à polir et traités à l’acide phosphorique, alors que les surfaces d’adhésion des restaurations ont été sablées avec des particules d’oxyde d’aluminium (50 μm, pression de 2,5 bars). Ensuite, douze restaurations ont été assemblées avec PANAVIA ™ V5, les douze autres avec PANAVIA™ F2.0 (une autre version plus ancienne de ciment de résine de Kuraray Noritake Dental Inc.). Après une période d’observation de 32 à 50,47 mois, les taux de réussite et de survie étaient de 100 % dans le groupe PANAVIA™ V5. Dans l’autre groupe, on a observé une fracture de connecteur, une ébréchure et deux décollages. Sur la base de ces résultats, les auteurs de la publication ont conclu que « il a été constaté que la nouvelle génération de ciment (PANAVIA™ V5) est plus performante »7.

CONCLUSION

Pendant de longues années, les approches de restauration indirecte mini-invasive comme le remplacement d’incisives manquantes par des prothèses dentaires fixes à adhésion résine ont été mises en oeuvre avec succès par certains praticiens dentaires. Toutefois, beaucoup d’autres semblent encore hésiter quant aux résultats qu’ils pourraient obtenir avec ces approches. Les résultats d’étude clinique disponibles ont cependant confirmé que la procédure est très avantageuse et promise à la réussite alors que les efforts de développement en cours dans le domaine des ciments de résine ont généré des produits qui font encore baisser les taux d’échec liés au décollage. Même si un décollage se produit, il n’entraîne généralement aucun dommage, de sorte que la restauration peut être recollée avec peu d’efforts. Ces conclusions – de même que les avantages bien connus de la dentisterie mini-invasive en général – devraient encourager les praticiens dentaires à commencer d’explorer pour eux-mêmes le plein potentiel de la dentisterie adhésive. Dans ce contexte, PANAVIA™ V5 est incontestablement un excellent choix.

References

1. Sasse M, Kern M. All-ceramic resin-bonded fixed dental prostheses: treatment planning, clinical procedures, and outcome. Quintessence Int. 2014 Apr;45(4):291-7. doi: 10.3290/j.qi.a31328. PMID: 24570997.
2. Tetsch J, Spilker L, Mohrhardt S, Terheyden H (2020) Implant Therapy for Solitary and Multiple Dental Ageneses. Int J Dent Oral Health 6(6): dx.doi. org/10.16966/2378-7090.332.
3. Wei YR, Wang XD, Zhang Q, Li XX, Blatz MB, Jian YT, Zhao K. Clinical performance of anterior resin-bonded fixed dental prostheses with different framework designs: A systematic review and meta-analysis. J Dent. 2016 Apr;47:1-7. doi: 10.1016/j.jdent.2016.02.003. Epub 2016 Feb 11. PMID: 26875611.
4. Kern M, Passia N, Sasse M, Yazigi C. Ten-year outcome of zirconia ceramic cantilever resin-bonded fixed dental prostheses and the influence of the reasons for missing incisors. J Dent. 2017 Oct;65:51-55. doi: 10.1016/j.jdent.2017.07.003. Epub 2017 Jul 5. PMID: 28688950.
5. Kern M. Fifteen-year survival of anterior all-ceramic cantilever resin-bonded fixed dental prostheses. J Dent. 2017 Jan;56:133-135.
6. Sasse M, Kern M. Survival of anterior cantilevered all-ceramic resin-bonded fixed dental prostheses made from zirconia ceramic. J Dent. 2014 Jun;42(6):660-3. doi: 10.1016/j.jdent.2014.02.021. Epub 2014 Mar 5. PMID: 24613605.
7. Bilir H, Yuzbasioglu E, Sayar G, Kilinc DD, Bag HGG, Özcan M. CAD/CAM single-retainer monolithic zirconia ceramic resin-bonded fixed partial dentures bonded with two different resin cements: Up to 40 months clinical results of a randomized-controlled pilot study. J Esthet Restor Dent. 2022 Oct;34(7):1122-1131. doi: 10.1111/jerd.12945. Epub 2022 Aug 3. PMID: 35920051.
8. Kern M. Bonding to oxide ceramics—laboratory testing versus clinical outcome. Dent Mater. 2015 Jan;31(1):8-14. doi: 10.1016/j.dental.2014.06.007. Epub 2014 Jul 21. PMID: 25059831.
9. Kern M, Beuer F, Frankenberger R, Kohal RJ, Kunzelmann KH, Mehl A, Pospiech P, Reis B. All-ceramics at a glance. An introduction to the indications, material selection, preparation and insertion techniques for all-ceramic restorations. Arbeitsgemeinschaft für Keramik in der Zahnheilkunde. 3rd English edition, January 2017.
10. Comino-Garayoa R, Peláez J, Tobar C, Rodríguez V, Suárez MJ. Adhesion to Zirconia: A Systematic Review of Surface Pretreatments and Resin Cements. Materials (Basel). 2021 May 22;14(11):2751.
11. Al-Bermani ASA, Quigley NP, Ha WN. Do zirconia single-retainer resin-bonded fixed dental prostheses present a viable treatment option for the replacement of missing anterior teeth? A systematic review and meta-analysis. J Prosthet Dent. 2021 Dec 7:S0022-3913(21)00588-6. doi: 10.1016/j.prosdent.2021.10.015. Epub ahead of print. PMID: 34893319.

ADHESIVE LUTING: A DRIVER OF INNOVATION

What would modern restorative treatments be like without the availability of high-performance (self-)adhesive resin cements? Tooth preparations would still be much more invasive due to the need for sufficient mechanical retention between the tooth and the restoration. At the same time, it would be impossible to restore teeth with many innovative, tooth-coloured materials such as low-strength ceramics and composite. In short, restorative dentistry would be much less developed than it is today.

When the first resin cements were introduced several decades ago, however, the achieved progress came at the expense of simplicity: Adhesive luting procedures were highly complex and the many different components quite technique sensitive. Luckily, this has changed over the years due to continued development efforts ultimately resulting in the products that are currently available. The resin cement line-up of Kuraray Noritake Dental Inc. consists of three main products: the dual-cure three-component system PANAVIA™ V5, the single-component dual-cure universal resin cement PANAVIA™ SA Cement Universal and the light-curing PANAVIA™ Veneer LC.

For those who would like to learn more about the three systems, this 10^th issue of the BOND Magazine is definitely worth reading. It reveals important details about the 40-year history of the PANAVIA™ brand, sheds light on the strengths of each resin cement to facilitate indication-specific cement selection and provides in-depth information about their clinical use. In addition, two articles are dedicated to hot topics around the luting of restorations made of zirconia, a popular restorative material that some still consider to be unsuitable for adhesive luting procedures. For everyone wondering how it is possible to successfully lute minimally invasive restorations made of zirconia, the article titled “Innovative resin cements forming the basis of minimally invasive prosthodontics” is highly recommended. Those unsure about how to proceed with 5Y-TZP should read the article “How to cement restorations made of high-translucency zirconia”. Interesting information about cleaning options prior to adhesive luting rounds out the content of this magazine.

Click here to read. Enjoy reading!

Start Reading: BOND | VOLUME 10 | 10/2023

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Case by Kanstantsin Vyshamirski

A male patient (47 years of age) presented to his dentist with severe damage to his teeth. His main request was to increase aesthetics, to achieve a more pleasing envisaged aesthetic area. A side request was to achieve a ‘whitening but natural look’. This was achieved by using a lighter colour palette of zirconia and porcelain materials.

The final result was achieved through the creation of a wax-up, followed by a mock-up, provisional restoration and finally adhesive bonding of the zirconia crowns.

INITIAL SITUATION

Fig. 1. Initial situation. Male patient (47 years of age).

Fig. 2. Planning the new smile according to patient’s aesthetic and functional parameters.

Fig. 3. Mock-up in place to check the new look in the patient’s mouth.

Fig. 4. KATANA™ Zirconia YML shade A1 crowns with labial cutback after milling.

Fig. 5. Crowns after sintering on the plaster model.

Fig. 6. Noritake CERABIEN™ ZR porcelain layering map.

Fig. 7. Finishing the labial surface using both polishing and selfglaze. On the palatal side of the crowns only CERABIEN™ FC Paste Stain stains and glaze were used for finishing. To aid in optimisation of the soft tissue condition the palato-cervical and near proximal areas were polished.

Fig. 8. Finished crowns on the plaster model.

Fig. 9. Try-in using PANAVIA™ V5 White try-in paste, to confirm the proper appearance. For the final adhesive cementation PANAVIA™ V5 White has been used.

FINAL SITUATION

Fig. 10. Situation after seven months. The result is aesthetically pleasing and the gingival condition excellent.

Fig. 11. Recall after 1.5 years.

Dentist:

KANSTANTSIN VYSHAMIRSKI

Kanstantsin started his dental technician career in 2014. His speciality is aesthetic prosthetic porcelain works. Kanstantsin is an experienced user of KATANA™ Zirconia and Noritake porcelains. He owns his lab in Riga, Latvia.

Photo credits to Giuliano Moustakis

Can you imagine a world without multi-layered zirconia? The invention of a zirconia material with natural colour gradation and well-balanced translucency and strength led to fundamental changes in the way zirconia-based restorations are produced. When the first product of its kind – KATANA™ Zirconia ML – was introduced to the dental market exactly ten years ago, dental technicians all over the world suddenly started rethinking their manufacturing concepts.

Since then, the trend towards a decreased thickness of the porcelain layer, a limiting of this layer to the vestibular area and the production of monolithic restorations is clearly perceivable. Technicians have developed their own concepts of micro-layering, which allow for more patient-centred approaches. This is also due to the fact that the total wall thicknesses of the restorations may be decreased without compromising the aesthetics. The line-up of multi-layered zirconia currently available from Kuraray Noritake Dental Inc. (KATANA™ Zirconia UTML, STML, HTML Plus and KATANA™ Zirconia YML with additional translucency and strength gradation) enables users to make indication-related material choices for the production of restorations that are precisely aligned to the individual demands of each case.

The reasons to choose KATANA™ quality

But why choose KATANA™ Zirconia instead of any other multi-layered zirconia disc? According to experienced users of the KATANA™ Zirconia Multi-Layered series, there are many reasons to opt for KATANA™.

For Jean Chiha, owner at North Star Dental Laboratories and Milling Center in Santa Ana, California, it is the combination of optical and mechanical properties that makes the difference: 

“KATANA™ Zirconia is the game changing material with well-balanced esthetics and strength!”. 

Naoki Hayashi, president of Ultimate Styles Dental Laboratory in Irvine, California, aesthetics is the most decisive argument to opt for the discs from Kuraray Noritake Dental Inc. He states:

“KATANA™ Zirconia discs offer trusted esthetics which gives me confidence in my clinical cases”.

Naoto Yuasa, chief ceramist at Otani Dental Clinic in Tokyo, adds predictability as an important factor:

“KATANA™ sustains my passions for aesthetic restorations and those of a predictable future in the long run”, whereas dependability is the key element.

For Hiroki Goto, the laboratory manager at Sheets and Paquette Dental Practice in Newport Beach, California reports:

“Without KATANA™ there is no pride. Haven’t experienced it yet? You have to see how reliable it is!”

Finally, we have asked Kazunobu Yamada, a pioneer in making porcelain laminate veneers using complementary color techniques and a first-hour user of KATANA™ Zirconia, what comes to his mind when thinking about KATANA™ Zirconia. According to the president of CUSP Dental Laboratory in Nagoya City, there is a clear link between the product name and its characteristics:

“Did you know that the word "KATANA" also means "protection against misfortune and evil"? Katana zirconia, the culmination of many years of research and development by Kuraray Noritake, has an unparalleled quality. KATANA™, for me, is truly "Protection for all technicians".”

The origin of well-balanced properties

It seems that the KATANA™ Zirconia Multi-Layered line-up stands out due to set of valuable properties enabling a dental technician to produce beautiful, high-quality restorations every time. The secret of success lies in meticulous raw material selection and controlled processing from the powder to the pre- sintered blank carried out at the production facilities of Kuraray Noritake Dental Inc. in Japan. They provide for the high product quality that is responsible for the materials’ outstanding behaviour supporting the best possible outcomes.

Clinical case by Dr. Florian Zwiener

The 85-year-old female patient presented after osteosynthesis of a multiple mandibular fracture she had sustained after a fall. During fixation, a massive nonocclusion had occurred in the left posterior region of the mandible (teeth 34 to 37; FDI notation). The patient desired to be able to chew properly again in this area. After endodontic treatment of the two avulsed central incisors, which had been replanted in the hospital, and periodontal therapy, a bite elevation was planned on the left side.

The idea was to restore the teeth and elevate the bite with three onlays and a crown made of lithium disilicate (IPS e.max CAD, Ivoclar Vivadent). During tooth preparation, however, a longitudinal root fracture was detected on the first molar. Therefore, only the first premolar was restored in this session. For this purpose, an onlay was produced chairside (with the CEREC system, Dentsply Sirona) and adhesively luted with PANAVIA™ V5 (Kuraray Noritake Dental Inc.). The first molar was extracted. One week later, the extraction socket, which was still healing, was modelled for the ovoid pontic using an electrotome loop. The second premolar and molar were prepared as abutment teeth for a bridge. The bridge was then milled from KATANA™ Zirconia Block for Bridge in the shade A3.5 and individualized with CERABIEN™ ZR FC Paste Stain (both Kuraray Noritake Dental inc.). After another week, the bridge was luted with the self-adhesive resin cement PANAVIA™ SA Cement Universal (Kuraray Noritake Dental Inc.) following sandblasting.

Fig. 1. Situation after multiple mandibular fracture on the left side.

Fig. 2. Clinical situation at the initial appointment in the dental practice.

Fig. 3. Open bite in the mandibular left posterior region.

Fig. 4. Bridge design …

Fig. 5. … using the CEREC Software.

Fig. 6. Due to the bright shade of the teeth in the cusp area, the restoration was positioned high in the KATANA™ Zirconia Multi-Layered Block.

Fig. 7. Surface texturing in the pre-sintered state (prior to the final sintering procedure).

Fig. 8. Bridge after a seven-hour sintering cycle.

Fig. 9. Appearance of the bridge after individualization with CERABIEN™ ZR FC Paste Stain …

Fig. 10. … and two glaze firings.

Fig. 11. Clinical situation after restoring the teeth with a lithium disilicate onlay and a zirconia bridge.

FINAL SITUATION

Fig. 12. Onlay and bridge in place (after adhesive luting with PANAVIA™ V5 and self-adhesive luting with PANAVIA™ SA Cement Universal).

Fig. 13. Final X-ray used to check for excess cement around the bridge.

Dentist:

DR. FLORIAN ZWIENER

Dr. Florian Zwiener is a distinguished dental professional known for his expertise in Endodontics, Prosthodontics, and CAD/CAM technology. Born in Cologne, Germany, he developed a passion for dentistry and pursued his education at the University of Cologne, where he obtained his degree in Dentistry. Currently, Dr. Florian Zwiener practices at the Dr. Frank Döring Dental Clinic in Hilden, Germany. Here, he continues to apply his specialized knowledge and skills, ensuring that his patients receive the highest quality of care. Follow Dr. Zwiener on Instagram: @dr.florian_zwiener.

Case by Kanstantsin Vyshamirski

A male patient (47 years of age) presented to his dentist with severe damage to his teeth. His main request was to increase aesthetics, to achieve a more pleasing envisaged aesthetic area. A side request was to achieve a ‘whitening but natural look’. This was achieved by using a lighter colour palette of zirconia and porcelain materials. The final result was achieved through the creation of a wax-up, followed by a mock-up, provisional restoration and finally adhesive bonding of the zirconia crowns.

Initial situation

Fig. 1. Initial situation. Male patient (47 years of age)

Fig. 2. Planning the new smile according to patient’s aesthetic and functional parameters.

Fig. 3. Mock-up in place to check the new look in the patient’s mouth.

Fig. 4. KATANA™ Zirconia YML shade A1 crowns with labial cutback after milling.

Fig. 5. Crowns after sintering on on the plaster model.

Fig. 6. Noritake CERABIEN™ ZR porcelain layering map.

Fig. 7. Finishing the labial surface using both polishing and selfglaze. On the palatal side of the crowns only CERABIEN™ FC Paste Stain stains and glaze were used for finishing. To aid in optimisation of the soft tissue condition the palato-cervical and near proximal areas were polished.

Fig. 8. Finished crowns on the plaster model.

Fig. 9. Try-in using PANAVIA™ V5 White try-in paste, to confirm the proper appearance. For the final adhesive cementation PANAVIA™ V5 White has been used.

Final situation

Fig. 10. Situation after seven months. The result is aesthetically pleasing and the gingival condition excellent.

Fig. 11. Recall after 1.5 years

Click here for the product page for more details

What can you expect to find online

- General information about:
- KATANA™ Zirconia YML
- CERABIEN™ ZR porcelains
- FC Paste Stain
- PANAVIA™ V5
- Full Product Assortment
- Safety Data Sheets
- Instructions For Use
- Technical Information

Kanstantsin started his dental technician career in 2014. His speciality is aesthetic prosthetic porcelain works. Kanstantsin is an experienced user of KATANA™ Zirconia and Noritake porcelains. He owns his lab in Riga, Latvia.

Case report with Dr. José Ignacio Zorzin

Rationalizing clinical workflows: This is the main reason for the use of universal products in adhesive dentistry. They are suitable for a wide range of indications and different application techniques, fulfil their tasks with fewer components than conventional systems and often involve fewer steps in the clinical procedure. Universal adhesives are a prominent example.

How do universal adhesives contribute to a streamlining of workflows?

When restoring teeth with resin composite, the restorative material will undergo volumetric shrinkage upon curing. By bonding the restorative to the tooth structure with an adhesive, the negative consequences of this shrinkage – marginal gap formation, marginal leakage and staining, hypersensitivity issues and the development of secondary caries – are prevented. The first bonding systems available on the dental market were etch-and-rinse adhesives, which typically consisted of three components: an acid etchant, a primer and a separate adhesive. Later generations combined the primer and the adhesive in one bottle, or were two or one-bottle self-etch adhesives. Universal adhesives (also referred to as multi-mode adhesives) may be used with or without a separate phosphoric acid etchant.

Fig. 1. Volumetric shrinkage of resin composite restoratives and its clinical consequences.

Which technique to choose depends on the indication and the clinical situation. In most cases, the best outcomes are obtained after selective etching of the enamel¹. Bonding to enamel is generally found more effective when the enamel is etched with phosphoric acid, while the application of phosphoric acid on large areas of dentin involves the risk of etching deeper than the adhesive is able to hybridize. When the cavity is small, however, selective application of the phosphoric acid etchant to the enamel surface may not be possible, so that a total-etch approach is most appropriate. Finally, in the context of repair, the self-etch approach may be the first choice, as phosphoric acid might impair the bond strength of certain restorative materials by blocking the binding sites. By using a universal adhesive, all these cases may be treated appropriately, as the best suitable etching technique can be selected in every situation.

Apart from the differences related to the use or non-use of phosphoric acid etchant on the enamel or enamel-and-dentin bonding surface, the clinical procedure is always similar with the same universal adhesive. The following clinical case is used to illustrate how to proceed with CLEARFIL™ Universal Bond Quick (Kuraray Noritake Dental Inc.) in the selective enamel etch mode, and it includes some details about the underlying mechanism of adhesion.

How to proceed with selective enamel etching?

A clinical example.

This patient presented with a fractured maxillary lateral incisor, luckily bringing the fragment with him. Hence, it was decided to adhesively lute the fragment to the tooth with an aesthetic flowable resin composite.

Fig. 2. Patient with a fractured maxillary lateral incisor.

Fig. 3. Close-up of the fractured tooth.

Fig. 4. Working field isolated with rubber dam.

As proper isolation of the working field makes the dental practitioner’s life easier, a rubber dam was placed using the split-dam technique. It works well in the anterior region of the maxilla, as the risk of contamination with saliva from the palate is minimal. Once the rubber dam was placed, the bonding surfaces needed to be slightly roughened to refresh the dentin. As the surfaces were also slightly contaminated with blood and it is important to have a completely clean surface for bonding, KATANA™ Cleaner was subsequently applied to the tooth structure, rubbed into the surfaces for ten seconds and then rinsed off. The cleaning agent contains MDP salt with surface-active characteristics that remove all the organic substances from the substrate. The fragment was fixed on a ball-shaped plugger with (polymerised) composite and also cleaned with KATANA™ Cleaner.

Fig. 5. Cleaning of the tooth …

Fig. 6. … and the fragment with KATANA™ Cleaner.

What followed was selective etching of the enamel on the tooth and the fragment for 15 seconds. Whenever selective enamel etching is the aim, it is essential to select an etchant with a stable (non runny) consistency – a property that is offered by K-ETCHANT Syringe (Kuraray Noritake Dental Inc.). Both surfaces were thoroughly rinsed and lightly dried before applying CLEARFIL™ Universal Bond Quick with a rubbing motion. This adhesive is really quick: Study results show that the bond established immediately after application is as strong and durable as after extensive rubbing into the tooth structure for 20 seconds.^2,3 The adhesive layer was carefully air-dried to a very thin layer and finally polymerized on the tooth and on the fragment.

Fig. 7. Selective etching of the enamel of the tooth …

Fig. 8. … and the fragment with phosphoric acid etchant.

Fig. 9. Application …

Fig. 10. … of the universal bonding agent.

Fig. 11. Polymerization of the ultra-thin adhesive layer on the tooth …

Fig. 12. … and the fragment.

What happens to dentin in the selective enamel etch (or self-etch) mode?

After surface preparation or roughening, there is a smear layer on the dentin surface that occludes the dentinal tubules, forms smear plugs that protect the pulp and prevents liquor from affecting the bond. When self-etching the dentin with a universal adhesive, this smear layer is infiltrated and partially dissolved by the mild self-etch formulation (pH > 2) of the universal adhesive. At the same time, the adhesive infiltrates and demineralizes the peritubular dentin. The acid attacks the hydroxyapatite at the collagen fibrils, dissolves calcium and phosphate and hence enlarges the surface. Then, the 10-MDP contained in the formulation reacts with the positively loaded calcium (and phosphate) ions. This ionic interaction is responsible for linking the dentin with the methacrylate and thus for the formation of the hybrid layer.^4,5

In the total-etch mode, the phosphoric acid is responsible for dissolving the smear layer and demineralising the hydroxyapatite. This leads to a collapsing of the collagen fibrils, which need to be rehydrated by the universal adhesive that is applied in the next step. Whenever the acid penetrates deeper into the structures than the adhesive, the collagen fibrils will remain collapsed. This will most likely result in clinical issues including post-operative sensitivity⁶.

When applying the adhesive system, a dental practitioner rarely thinks about what is happening at the interface⁷. However, every user of a universal adhesive should be aware of the fact that a lot is happening there. This is why it is so important to use a high-performance material with well-balanced properties and strictly adhere to the recommended protocols.

Fig. 13. Schematic representation of dentin after tooth preparation: The smear layer on top with its smear plugs occluding the dentinal tubules protects the pulp and prevents liquor from being released into the cavity.

Fig. 14. Schematic representation of dentin after the application of a universal adhesive containing 10-MDP: The mild self-etch formulation partially dissolves and infiltrates the smear layer, while at the same time demineralizing and infiltrating the peritubular dentin5.

In the present case, the tooth and the fragment now needed to be reconnected. For this purpose, CLEARFIL MAJESTY™ ES-Flow (A2 Low) was applied to the tooth structure. The fragment was then repositioned with a silicone index, held in the right position with a plier and light cured. To obtain a smooth margin and glossy surface, the restoration was merely polished. The patient presented after 1.5 years for a recall and the restoration was still in a perfect condition.

Fig. 15. Reconnecting the fragment with the tooth structure.

Fig. 16. Treatment outcome.

Why is it important to adhere to the product-specific protocols?

Universal adhesives contain lots of different technologies in a single bottle. While this fact indeed allows users to rationalize their clinical procedures, it also requires some special attention. As every highly developed material, universal adhesives need to be used according to the protocols recommended by the manufacturer. In general, materials may only be expected to work well on absolutely clean surfaces, while contamination with blood and saliva is likely to decrease the bond strength significantly. Depending on the type of universal adhesive, active application is similarly important, as is proper air-drying and polymerization of the adhesive layer. In addition, care must be taken to use the material in its original state, which means that it needs to be applied directly from the bottle to avoid premature solvent evaporation or chemical reactions. When adhering to these rules, universal adhesives offer several benefits from streamlined procedures to simplified order management and increased sustainability, as fewer bottles are needed and likely to expire before use.

Dentist:

DR. JOSÉ IGNACIO ZORZIN

Dr. José Ignacio Zorzin graduated as dentist at the Friedrich-Alexander University of Erlangen-Nürnberg, Germany, in 2009. He obtained his Doctorate (Dr. med. dent.) in 2011 and 2019 his Habilitation and venia legendi in conservative dentistry, periodontology and pediatric dentistry (“Materials and Techniques in Modern Restorative Dentistry”). Dr. Zorzin works since 2009 at the Dental Clinic 1 for Operative Dentistry and Periodontology, University Hospital Erlangen. He lectures at the Friedrich-Alexander University of Erlangen-Nürnberg in the field of operative dentistry where he leads clinical and pre-clinical courses. His main fields of research are self-adhesive resin luting composites, dentin adhesives, resin composites and ceramics, publishing in international peer-reviewed journals.

References

1. Van Meerbeek, B.; Yoshihara, K.; Van Landuyt, K.; Yoshida, Y.; Peumans, M. From Buonocore‘s Pioneering Acid-Etch Technique to Self-Adhering Restoratives. A Status Perspective of Rapidly Advancing Dental Adhesive Technology. J Adhes Dent 2020, 22, 7-34.
2. Kuno Y, Hosaka K, Nakajima M, Ikeda M, Klein Junior CA, Foxton RM, Tagami J. Incorporation of a hydrophilic amide monomer into a one-step self-etch adhesive to increase dentin bond strength: Effect of application time. Dent Mater J. 2019 Dec 1;38(6):892-899.
3. Nagura Y, Tsujimoto A, Fischer NG, Baruth AG, Barkmeier WW, Takamizawa T, Latta MA, Miyazaki M. Effect of Reduced Universal Adhesive Application Time on Enamel Bond Fatigue and Surface Morphology. Oper Dent. 2019 Jan/Feb;44(1):42-53.
4. Fehrenbach, J., C.P. Isolan, and E.A. Münchow, Is the presence of 10-MDP associated to higher bonding performance for self-etching adhesive systems? A meta-analysis of in vitro studies. Dental Materials, 2021. 37(10): 1463-1485.
5. Van Meerbeek, B., et al., State of the art of self-etch adhesives. Dental Materials, 2011. 27(1): 17-28.
6. Pashley, D.H., et al., State of the art etchand-rinse adhesives. Dent Mater, 2011. 27(1): 1-16.
7. Vermelho, P.M., et al., Adhesion of multimode adhesives to enamel and dentin after one year of water storage. Clinical Oral Investigations, 21(5): 1707-1715.

Certaines entreprises utilisent principalement des technologies de base développées par d‘autres afin d‘améliorer leurs produits et d‘en introduire de nouveaux, alors que d‘autres sociétés mènent des recherches fondamentales et développent la technologie en interne. Cette différence est-elle importante pour ceux qui utilisent les produits en résultant au cabinet ou laboratoire dentaire au quotidien ? C‘est le cas - étant donné que les entreprises qui développent tout à partir de rien disposent généralement d‘une compréhension plus approfondie des produits et de leurs procédures de production, ce qui leur permet de modifier plus facilement certaines caractéristiques, de résoudre certains problèmes et de répondre aux besoins sur le marché. Cet article décrit l‘impact de plusieurs technologies de base développées par Kuraray Noritake Dental Inc. concernant le flux de travail associé à la création de restaurations composite directes.

Les restaurations directes - de la complexité à la simplicité

La dentisterie restaurative adhésive utilisant des adhésifs dentaires et résines composites haute performance est actuellement l‘un des plus populaires traitements des dents avec lésions carieuses. De nos jours, un flacon unique d‘adhésif universel et une ou deux nuances et opacités de composite universel suffisent généralement pour obtenir des résultats esthétiques et durables, à condition de sélectionner les bons matériaux. Toutefois, cela n‘a pas toujours été le cas. Pendant longtemps, les techniques utilisées pour créer des restaurations directes étaient assez complexes : les adhésifs étaient des flacons multiples sensibles à la technique appliquée et des systèmes à étapes multiples avec des temps d‘application longs. D‘un autre côté, les matériaux de charge composites ne produisaient des résultats naturels qu‘à grands renforts de nuances et opacités différentes et combinées correctement. Et, même lorsque les procédures complexes étaient mises en oeuvre correctement, le risque de microfuite, décoloration et caries secondaires au final était relativement élevé. Kuraray Noritake Dental Inc. a misé sur le solutionnement de ces problèmes à un stade relativement précoce, en commençant par l‘utilisation du monomère MDP original développé en 1981.

Optimiser la perfomance d'adhésion

Le monomère MDP original répondait au problème de durabilité limitée de la performance d‘adhésion des systèmes adhésifs. Le groupe hydrophile (phosphate) du MDP forme une liaison chimique particulièrement solide et durable avec le calcium de l‘hydroxyapatite, le principal composant de l‘émail et de la dentine. Le sel MDP-Ca formé procure la base pour une couche hybride stable, solide et durable. En combinaison avec la résine de l‘agent adhésif, le résultat est un scellement hermétique de la cavité après photopolymérisation. Jusqu‘à l‘heure actuelle, le MDP est un composant essentiel de tout produit adhésif de Kuraray Noritake Dental Inc., et c‘est le composant clé qui a fait de CLEARFIL™ SE Bond le système adhésif à auto-mordançage de référence absolue.

Cependant, convaincue que les adhésifs dentaires devaient apporter davantage qu‘une seule adhésion solide et durable, Kuraray Noritake Dental Inc. a commencé à se pencher sur un autre problème : le risque de déminéralisation et de cavitation causé par les bactéries restées dans la cavité. Sur la base de son expérience dans le développement d‘autres monomères adhésifs, Kuraray Noritake Dental Inc. a inventé le monomère MDPB qui a pour une action de nettoyage antibactérien de cavité. Différent d‘autres agents antibactériens qui pourraient nuire à la solidité de l‘adhésion d‘un adhésif appliqué ultérieurement, le monomère MDPB détruit les bactéries persistantes sans affecter la performance d‘adhésion. Il est contenu dans l‘apprêt de l‘adhésif à auto-mordançage en deux flacons CLEARFIL™ SE Protect et est immobilisé par polymérisation.

Le mécanisme bactéricide du MDPB est supposé similaire à celui de l‘agent antibactérien bien connu qu‘est le CCP (chlorure de cétylpyridinium), qui est contenu dans de nombreux dentifrices et bains de bouche.

Si l‘adhésif à auto-mordançage en deux flacons a simplifié la procédure d‘adhésion, la version en flacon unique a permis d‘aller encore plus loin. Réunir les ingrédients des systèmes en étapes multiples dans un seul flacon sans compromettre la stabilité du produit relève du défi. La technologie actuelle permet désormais cela. Pour sceller la surface le plus tôt possible après l‘application, la pénétration des monomères dans le tissu dentaire doit être rapide et efficace. En général, la pénétration est toutefois ralentie par les monomères qui ont besoin de temps pour pénétrer la structure dentaire - en particulièrement la dentine humide - et requièrent parfois même un mouvement de friction à cette fin. C‘est pourquoi Kuraray Noritake Dental Inc. s‘est concentrée sur le développement de la Rapid Bond Technology. Elle consiste dans le monomère MDP original associé aux monomères hydrophiles à réticulation d‘amide nouvellement développés et intégré à CLEARFIL™ Universal Bond Quick. Les monomères amides hydrophiles permettent une pénétration rapide, complète et profonde dans la dentine et forment avec la polymérisation un dense réseau polymère réticulé responsable d‘une adhésion solide et durable. Ainsi, les temps de friction et d‘attente sont supprimés et un scellement hermétique et durable de la cavité est réalisé après photopolymérisation.

En raison de leur hydrophilie (affinité avec l‘eau), les monomères amide de la Rapide Bond Technology pénètrent très bien la dentine. Après photopolymérisation, l‘adhésion présente une faible absorption d‘eau et donc une grande résistance dans le temps.

Optimiliser les restaurations directs

Combiner plusieurs couches, nuances et opacités : Heureusement, l‘utilisation de techniques de stratification très complexes pour créer des restaurations composite naturelles appartient au passé dans de nombreuses situations cliniques. En effet, les résines composites hautement développées se mélangent parfaitement à la structure dentaire adjacente. Pour fournir cette caractéristique favorable, Kuraray Noritake Dental Inc. a développé sa propre technologie de diffusion de la lumière (« Light Diffusion Technology », LDT). Cette technologie est incorporée dans des charges spécialement pré-polymérisées qui agissent comme des millions de micro-prismes transmettant et réfractant la lumière et la couleur depuis la structure dentaire alentour. Optimisés en taille, distribution et indice de réfraction par rapport à la matrice, les charges offrent un mélange naturel incomparable. L‘ensemble de la gamme de composites CLEARFIL MAJESTY™ contient cette technologie de charge maison. CLEARFIL MAJESTY™ ES-2 Universal, le dernier produit dans lequel Kuraray Noritake Dental Inc. fait usage du niveau supérieur de LDT permet une technique à nuance unique avec simplification de la sélection de nuance : il est disponible en deux nuances pour la zone antérieure et en une nuance unique pour la zone postérieure, mais se mélange si bien qu‘une couverture de quasiment chaque nuance du nuancier VITA classique A1-D4 est obtenue.

La réfraction et la transmission de la lumière sont le moyen d‘obtenir une excellente intégration optique : les charges de diffusion de la lumière de CLEARFIL MAJESTY™ ES-2 de Kuraray Noritake Dental Inc.

Étant donné qu‘un excellent aspect ne dépend pas seulement de l‘intégration optique et de marges de restauration indétectables, Kuraray Noritake Dental Inc. a également développé des charges qui assurent le reste, à savoir une brillance de surface naturelle et une rétention de polissage durable. La solution intégrée dans CLEARFIL MAJESTY™ ES Flow avec ses trois niveaux de fluidité est appelée « Submicron Filler Technology », consistant en des charges brillantes de taille submicronique. Ces charges sont si petites que les réflexions lumineuses offrent un effet naturel, même après usure. L‘exceptionnelle technologie silane de Kuraray Noritake Dental Inc. est utilisée pour rassembler des millions de ces charges submicroniques et les maintenir ensemble dans la durée. Elle permet des charges élevées dans les composites de faible viscosité et limite l‘absorption d‘eau qui entraînerait autrement une dégradation du composite polymérisé. L‘équilibre parfait entre les charges submicroniques brillantes, les charges de diffusion de la lumière, la matrice de résine et la propre technologie silane offre une combinaison équilibrée de propriétés mécaniqueset optiques.

Exemple d‘une restauration « single-shade » avec CLEARFIL MAJESTY™ ES-2 Universal.

Conclusion

Monomères adhésifs, technologies de charge et technologie silane procurent une solide combinaison de charges, clusters et matrice résine : Clairement, Kuraray Noritake Dental Inc. est un expert de confiance dans le domaine des restaurations adhésives. Ses propres technologies développées au cours des dernières décennies ont incontestablement contribué à améliorer (à long terme) la performance des restaurations directes et à faciliter l‘obtention de résultats fiables et esthétiques.

Interview with Andreas Chatzimpatzakis

Fewer bakes, fewer ceramic powders - there is clearly a trend toward simplification in the production of zirconia-based prosthetic work. This is also true for implant-based restorations, which often involve gum parts. DT Andreas Chatzimpatzakis, international trainer for Kuraray Noritake Dental Inc., and the owner of ACH Dental Laboratory in Athens, Greece, shares his approach to high aesthetics in implant prosthodontics in the following conversation.

You are a user of the CERABIEN™ ZR portfolio from the outset. When did you test the products for the first time and why?

Well, it was many years ago when I finished my very first zirconia-based restoration. The reason to test CERABIEN™ ZR was that when I asked the dental technician who had milled the framework which porcelain system to use. He suggested to use CERABIEN™ ZR, which I did. I was immediately impressed by the system and by the outcome I was able to achieve on the first attempt.

Did you ever test any other porcelain systems for ceramic layering?

Yes. Before I becoming an international trainer for Kuraray Noritake Dental Inc., I had the opportunity to test many other porcelain systems for layering on zirconia. Based on this experience, I can say that CERABIEN™ ZR is unique and the best system I have ever used. The reason is that its translucency and chroma are extremely close to natural teeth. In addition, due to a controlled firing shrinkage, a One-Bake Technique may be employed even in long-span restorations.

Your hands-on demonstration at the Kuraray Noritake Dental booth during the IDS 2023 in Cologne focused on White and Pink Aesthetics achieved with CERABIEN™ ZR. Is there a specific concept you use?

Nowadays, everyone producing dental restorations – no matter whether based on natural teeth or on implants – is confronted with increasing aesthetic demands of patients and dental practitioners. The high demands are developed because life-like restorations and cosmetic dental treatment outcomes are presented everywhere in the web and on social media. The showcased quality of outcomes is simply expected, even if the financial budget is limited. To be able to fulfil these demands in the field of implant-based prosthodontics, I have developed an approach that allows me to achieve high aesthetics with little effort. My concept is based on using not too many ceramic powders. For extra chroma and special characterization, I rely on the power of the internal live stain technique, first introduced by Hitoshi Aoshima-sensei.

Please summarize the most important details of your presentation.

The first important detail is the design and characterization of the framework. Before sintering, I apply Esthetic Colorant for KATANA™ Zirconia. After the sintering process, shade base stain and internal stains are mixed and applied. In this way, I create a nice canvas that helps me to achieve a life-like result with only a few selected ceramic powders. In most cases, three to five powders are enough to produce a great result. Among the powders used most frequently are Opacious Body, Body, LTX, Mamelon and CCV. After the first bake and a little grinding, I make use of internal stains again. They offer support in the controlling of the chroma and the integration of special characteristics. When this step is completed, the final build-up is done with one or two ceramic powders, most of the times LT1 and Enamel or LT0. Pink aesthetics are usually created with Tissue 1, 3 and 5. For the free gingiva, LT Coral is my go-to solution. The major goal is always to obtain maximum quality in a minimum of time. To achieve this, a good knowledge of the materials and of course practicing – on both, porcelain build-up and morphology – are strictly required.

Fig. 1. Complex implant-based restoration: Framework design.

Fig. 2. Esthetic Colorant …

Fig. 3.  … applied prior to the final sintering procedure.

Fig. 4. Appearance after sintering.

Fig. 5. Final outcome.

Are there any concrete tips and tricks you would like to share?

For the characterization of the framework, I mix the internal stains with shade base stain powders; mostly with SS Fluoro. For the first bake, especially when the restoration is large and the amount of ceramic to be applied huge, I reduce the heating rate up to 38 degrees per minute. I also increase the drying process up to 17 or even 20 minutes depending to the restoration. Experience shows that these measures optimize the aesthetic outcomes.

You often mention that it is extraordinarily important to understand the morphology of natural teeth to be able to produce beautiful restorations. Why is this the case?

A successful prosthetic restoration needs to offer proper function and aesthetics. Function means a precise fit, perfect contact points and occlusion, a proper emergence profile and interproximal embrasures for self-cleaning etc. All this is described by the term morphology. Aesthetics, on the other hand, is guided by shape and colour. The effort required to establish a proper morphology is much higher (about 70 percent of the total work) than the effort involved in obtaining the right translucency, opalescence and chroma.

What instruments do you use to imitate the morphology of natural teeth and how do you do it?

I usually make use of the Optimum™ Spring Ceramic Brush Size 8 (MPF Brush Co.), stones and diamond burs for detailed grinding and carving after the final bake. I studied morphology at the Osaka Ceramic Training Centre in Japan with Shigeo Kataoka-sensei. According to him, a key factor in creating a perfect macro and micro morphology lies in the shadows. To be able to take into account the interference of light and shadow during grinding, a light source is placed on one side of the restoration.

How many bakes do you need to produce highly aesthetic restorations?

It depends on the case, although in many situations, I nowadays opt for some kind of micro-layering. Lately, I have used micro-layering a lot with internal stain directly on the zirconia framework. In other cases, I do a quick first bake, then the internal staining, a final bake and glazing. For small or single-unit restorations in the posterior region, a One-Bake Technique is often sufficient. Even a Zero-Bake approach using Esthetic Colorant on a monolithic zirconia restoration may be appropriate here, and it is very convenient. If there is a restoration with high aesthetic demands – these are typically single anterior restorations – the technique I select depends on the shade. In some cases, using only the internal stain technique is enough to reach a high aesthetic level, while in other cases, additional steps need to be taken. To my mind, there is no single technique that fits all cases. As mentioned before, I try to achieve high aesthetics in a minimum of time.

Fig. 6. Clinical example of achieving high aesthetics in a minimum of time: Before …

Fig. 7. … and after crown placement.

Fig. 8. High aesthetics …

Fig. 9. … achieved in a minimum of time.

Did your approach change due to the availability of high-translucency zirconia materials with colour (and flexural strength) gradation?

Well, yes! My overall approach changed more to micro-layering. Several years ago, we needed to consider how to mask the framework and how to achieve translucency in areas with limited space. The problem was solved for single-unit and small anterior bridge restorations with the availability of KATANA™ Zirconia UTML and STML. With the introduction of KATANA™ Zirconia YML, a high-translucency material became available for long-span or implant-based restorations as well. We have strength and translucency all in one disc. In most of my cases, the framework material replaces the dentin with regard to morphology and shade. Hence, I need to focus on adding the enamel by applying the transparent and translucent powders. The powders of the internal stain technique are used to characterize the framework, and with a micro-layer of porcelain, the goal of creating an aesthetic restoration in the minimum of time is achieved. This is exactly why I am sure that micro-layering is the future.

What drives you to share your knowledge with others?

My passion! I love my work! And I love to see technicians become better and better. Dental technology is an exciting journey, a journey that begins when the first impression arrives in the dental laboratory, and it ends when the final restoration is cemented into the patient’s mouth. And this journey is so exciting because we change lives. We change people’s personalities, we give them back their smile, we give them back their self-respect. Consider that every day, every single moment working on our bench trying to imitate nature… there is nothing more exciting than that!!!

My approach as an instructor is to lead dental technicians to master the art of observing natural teeth. This is the way every individual will understand morphology and shade. You need no special talent to be a very good dental technician. You need to observe! Your eyes see, your mind understands, and your hands will follow.

Alexander (Alek) Aronin is a master dental technician who dedicated himself to the creation of high-end, handmade porcelain restorations. He runs a dental laboratory and morphology school in Spain, and travels the world as a lecturer and teacher.

The greatest source of inspiration in his professional life is the book Collection of Ceramic Works by Hitoshi Aoshima. Through reading it in 1996, he discovered superb outcomes of working with dental ceramics. Moreover, the book’s content made him realize that the creation of handmade porcelain work is a result of special education and manual skills. Those who want to become masters need a lot of commitment and a striving for continuous improvement, which Alek shows in his work and his classes. We talked to him about his philosophy and his enthusiasm for the creation of lifelike restorations. He shared with us his perspective on the future of dental technology and gave some practical tips on how to achieve a high level of professional satisfaction.

Photo courtesy of Dennis Debiase

Alek, many dental technicians decide to focus on CAD/CAM technology and automated processing of dental ceramics. Due to improvements on the material side, a handmade porcelain layer is no longer necessary in many clinical cases. In this context, the manual refinement process is reduced to a minimum. Why did you decide to take a completely different path and focus on fully manual dental craftsmanship?

The shift towards automated processing is not a matter of choice for dental technicians rather, it is a natural response to the evolution of technology. The high-end manual refinement process remains unchanged. The human element, from communication to hand crafting among skilled individuals and demanding clients, has been a constant so far throughout history. This traditional connection remains stable for centuries.

Digitalisation is not the revolution in the dental industry, and I do not see the benefit of it in our narrow specialization yet. In the area we are working, we do all steps of our case faster, incomparably more precise and more profitable. But we are keeping eye on machines and waiting for a suitable one.

Machines and automated processes widely serve mass production businesses focused on fast, affordable and uniform results in a highly competitive field. Our goal and workflow are different - we provide individual work and personal attention to each of our partners and patients.

So, we do not compete with the production labs and do not interrupt each other, we coexist in parallel worlds as always. A small number of dentists and their patients will always demand personal attention and valued restorations and service of the highest quality.

Many dental technicians admire your work. Yet, you continue to strive for improvement. Why is this the case?

On one side, we are limited by static ceramic material used to mimic dynamic natural teeth that keep changing for a lifetime. On the other side, we are limited by our manual skills. I am still far away from my teachers and Japanese colleagues. My target is to improve the fabrication process. My goal is to achieve the simplicity and imperfectness like Aoshima-sensei.

Alek lecturing at the IDS 2023 in Cologne.
Photo courtesy of Dennis Debiase

We are enjoying the outcome, but prefer to focusing on the improvement of the process, and move on to create a better one. This is what I am learning in Japan, and this is what I teach my students.

Talking about learning: What are the most important aspects a dental technician who wants to improve his skills should have in mind when looking for a good teacher?

Manual skills are very important, but not the only aspect that should be taken into account. Every individual should be motivated and guided and this is a teacher’s job.

I love the traditional Japanese way of teaching and learning: The teachers are passionate, leading the way by evoking emotions and manual skills to bring the best out of every single student. My personal advice for dental technicians who want to become masters in the creation of lifelike high-end dental restorations is to select their teachers carefully and go to a private school or courses whenever they have the chance.

What are the most important tools a dental technician needs to use when trying to create high-end lifelike restorations?

I suggest to focus on four aspects:

1. Documentary dental photography - required for documentation and communication with the dental office and patients using constant (once set and never changed) parameters of the photo equipment.
2. Focus to the biomimetic additive dentistry. This is a minimum machine invasive field. Dental technicians and dentists should be able to develop a deep knowledge about clinical and lab-side procedures to be able communicate with each other.
3. Mastering morphology and function (shape carving), and anatomy (internal staining), which comes with value control and mimicking fine tooth details for best integration in the mouth.
4. Written communication (stop phone calls) is very important, this is the way how to exchange the information between the patient, clinic and lab by strict protocols.

I teach these complex skills in my morphology school and in many of my trainings worldwide. Focusing on the four aspects, a dental technician has a great chance to become a good specialist in a relatively short period of time in a narrow field.

Is material selection important for achieving great results?

I’ve been using Noritake ceramic for most of my life, and the reason is simple: Noritake created their EX-3 porcelain over 40 years ago, and it was so well-made that it has not needed any changes since.

This is showing their consistently high quality and creates unbroken succession in the valuable tradition of passing on techniques and knowledge.

Today, among different generations of dental technicians, we can use and share the same methods, vocabulary and abbreviations, powders, and temperature charts developed by our skilled teachers 30 to 40 years ago. This unique feature sets Noritake and Creation porcelains apart from all other brands and systems in the world.

The other Noritake porcelain I use quite frequently is CERABIEN™ ZR, which is also well-tried and tested and has even some more advantages than EX3.

Is there any final advice you would like to give?

To become a good professional, I suggest to developing in four parallel directions:

1. Practicing on phantoms - fabricating cases and ceramic samples. It helps to experiment and practice with varied materials and techniques.
2. Implementing the achieved techniques in clinical cases.
3. Working with case presentation PowerPoint or Keynote: documenting the working steps in pictures and videos from beginning to end.
4. Mastering the communication using e-mails. Constantly calibrate and adjust the information exchange process between the clinic and lab. Acquire deeper knowledge about the work of each other.

Good luck!