Case by Vasiliki Tsertsidou

What kind of resin composite is recommended for core build-up procedures? While there are specific dual-cure core build-up resin composites available on the market, it is not mandatory to use them. Light curing is advisable to be applied even for materials with dual-cure polymerization. Some conventional resin composites demonstrate more favourable properties for a core build-up compared to specific core build-up resin composites itself.¹ Hence, it is possible to utilize a composite generally used in the dental office, provided it is indicated to and it is not applied deep within the root canal, where proper light curing would be impossible. The critical material properties for core build-ups are high filler load, sufficient flexural modulus and flexural strength.

CLEARFIL MAJESTY™ ES-2 composite series (Kuraray Noritake Dental Inc.) are suitable option for this case. With a filler load weight percentage of 78 and a flexural strength of 118 MPa (according to manufacturer), CLEARFIL MAJESTY™ ES-2 Classic corresponds to core build-up prerequisites*. The following case is illustrating the clinical procedure.

*The indication range of CLEARFIL MAJESTY™ ES-2 composite does not cover core build-up. In the specific case it is used for creating a large Class II filling where all conditions from the IFU, such as curing depth, are met.

Fig. 1. Endodontically treated tooth with a vertical fracture of palatal wall on maxillary right second premolar.

Fig. 2. Buccal view of the tooth.

Fig. 3. Clinical image, directly after removal of fragment.

Fig. 4. Fragment of the maxillary right second premolar.

Fig. 5. Circumferential matrix band for build-up to assist endodontic retreatment.

Fig. 6. Build-up of the missing walls (margin relocation) with CLEARFIL MAJESTY™ ES-2 Classic (A3).

Fig. 7. Temporary filling of the cavity.

Fig. 8. Replacement of the temporary filling material with CLEARFIL MAJESTY™ ES-2 Classic.

Fig. 9. Crown preparation.

Fig. 10. Proximal carious lesion present on the adjacent fist premolar.

Fig. 11. Situation after rubber dam placement and caries removal.

Fig. 12. Cavity restored with CLEARFIL MAJESTY™ ES-2 Classic.

Fig. 13. Prepared crown.

Fig. 14. Crown after sandblasting of the intaglio.

Fig. 15. Mechanically cleaned abutment tooth ready for pre-treatment.

Fig. 16. Intaglio of the crown treated with CLEARFIL™ CERAMIC PRIMER PLUS.

Fig. 17. Etching of the composite surface with phosphoric acid gel.

Fig. 18. Air-drying of PANAVIA™ V5 Tooth Primer on the abutment tooth.

Fig. 19. Crown in place after cementation with PANAVIA™ V5 Paste and excess removal.

A GOOD CHOICE

Dual-cure core build-up resin composites are two-component materials that need to be mixed homogeneously, which obstracts composition from containing high filler load. However, to prevent deformation of the core, a highly filled composite is advisable. This better simulates the flexural modulus of natural tissues compared to materials with low filler load. Consequently, a light-curing material like CLEARFIL MAJESTY™ ES-2 might be a better option. Applied in 2-mm increments in the core area (and not in the root canal), it performs well and provides the desired outcomes. Additionaly, the option of utilising the same material as for any other type of direct restorations is simplifying the stock management and supporting dental practitioners striving for a simplification of clinical procedures.

References

1. Spinhayer L, Bui ATB, Leprince JG, Hardy CMF. Core build-up resin composites: an in-vitro comparative study. Biomater Investig Dent. 2020 Nov 3;7(1):159-166. doi: 10.1080/26415275.2020.1838283. PMID: 33210097; PMCID: PMC7646551.

Dentist:

VASILIKI TSERTSIDOU

Gyd Clarence Tam, HBSC, DDS, AAACD, FIADFE

Porcelianinių laminačių (venyrų) naudojimas priekinių dantų formai, atspalviui ir vizualinei padėčiai pagerinti ir atkurti yra įprastas estetinės odontologijos metodas. Biomimetinis dantų restauravimo tikslas yra ne tik estetika, bet ir funkciniai aspektai. Labai svarbu pažymėti, kad būtent nepažeistas gomurinio ir lūpinio paviršių emalis priekiniuose dantyse užtikrina įgimtą lenkiamąjį stiprį. Jei danties struktūra buvo pažeista dėl endodontinės prieigos, ėduonies ir (arba) traumos, reikia dėti visas pastangas, kad būtų išsaugota likusi struktūra, ir stengtis atkurti arba viršyti pradinį sveiko danties funkcionalumo lygį.

ISTORIJA

55 metų ASA II pacientė atvyko į odontologijos kabinetą dėl dantų balinimo. Buvo numatyta, kad dantų balinimas neturės įtakos jau esamos 1.2 danties porcelianinės laminatės atspalviui. Šį dantį reikės iš naujo tvarkyti baigus procedūrą, ypač jei atspalvio vertės pokyčiai bus reikšmingi. Iš pradžių pacientės dantys buvo išbalinti iki pradinio atspalvio VITA* 1M1:2M1 50:50 santykiu viršutinėje priekinėje srityje ir 1M1 apatinėje priekinėje srityje. Įgyvendinus naktinio balinimo kapa protokolą naudojant 10 proc. karbamido peroksidą per naktį 3–4 savaites, pacientei pavyko pasiekti VITA* 0M3 atspalvį tiek viršutiniame, tiek apatiniame lanke. Dėl to atsirado reikšmingas verčių neatitikimas tarp 1.2 danties su laminate ir gretimų dantų, be to, pastebėtas kontralateralinio 2.2 danties spalvos intensyvumas dėl lūpinį paviršių apimančios III klasės kompozito restauracijos. Pastarasis dantis savo matmenimis taip pat neatitiko kontralateralinio danties, todėl buvo nuspręsta abu šoninius kandžius padengti surištomis ličio disilikato laminatėmis (venyrais). Šalia esančiame iltiniame dantyje (2.3) buvo lokalizuotas lengvas ar vidutinio sunkumo gumburo viršūnės dilimas, tačiau pacientė nenorėjo šio dilimo taisyti, kol nebuvo uždėtos aptariamos laminatės. Šio etapo planuojamos šypsenos tikslas – abiejų pusių harmonija, atsižvelgiant į tai, kad artimiausiu metu planuojama sukurti papildomą netiesioginę restauraciją, atkursiančią 2.3 danties lūpinio paviršiaus apimtį ir gumburio viršūnės trūkumą.

PROCEDŪRA

Pirminiam planui, t. y. atskiram šoninių kandžių tvarkymui, skaitmeninio šypsenos dizaino protokolo nereikėjo. Leidžiamas nedidelis šio tipo dantų pokytis, nes tai yra šypsenos ypatumo ir lyties žymuo. Prieš taikant anesteziją buvo parinktas tikslinis atspalvis analizuojant nuotraukas, padarytas naudojant retraktorių ir naudojant arba ne poliarizacinius filtrus. Nuotraukos buvo paruoštos skaitmeninio atspalvių kalibravimo tikslais darant atskaitos vaizdus su 18 proc. neutralia pilkai balta pusiausvyros kortele (1 pav.).

1 pav. Referencinė nuotrauka, padaryta naudojant 18 proc. neutralią pilką kortelę

Pagrindinis atspalvis buvo VITA* 0M2 su bloko atspalviu BL2. Pacientei buvo atlikta anestezija naudojant 1,5 karpulės 2 proc. lidokaino tirpalą su 1:100 000 epinefrinu, prieš tai uždėjus padalytą koferdamą. 1.2 danties laminatė buvo perpjauta ir pašalinta iš 1.2 danties, o 2.2 dantyje baigtas minimaliai invazinis laminatės paruošimas (2 pav.). Dalinis senos restauracijos iš kompozitinės dervos keitimas buvo baigtas 12 danties mezialiniame kandamojo krašto lūpiniame ir gomuriniame paviršiuose išlaikant nepažeistą segmentą. Adhezija su senu kompozitu buvo pasiekta naudojant mikrodalelių abraziją ir silanavimo medžiagą (CLEARFIL™ CERAMIC PRIMER PLUS). Kraštai buvo išlyginti, o retrakciniai siūlai įterpti suvilgius aliuminio chlorido tirpalu. Buvo užfiksuoti paruošto danties atspalviai. Galutiniai atspaudai buvo padaryti naudojant tiek skystos, tiek tirštos konsistencijos polivinilsiloksaną metaliniame šaukšte. Pacientei buvo sukurta laikina konstrukcija ir jai nurodyta, kad reikės patikrinti atspalvį laboratorijoje pirminio kepinimo stadijoje. Laboratorijoje parengti modeliai patvirtino minimaliai invazinį atvejo pobūdį.

2 pav. 1.2 ir 2.2 dantų laminačių paruošimas

Pradėjus dirbti pacientei taikytas skausmo malšinimas ir laikinosios medžiagos pašalintos. Apdorotini paviršiai buvo nuvalyti ir paruošti surišimo procedūrai nušlifavus paviršius 27 mikronų aliuminio oksido milteliais 30–40 psi slėgiu. Laminatės įvertintos naudojant skaidrią glicerino bandomąją pastą („PANAVIA™ V5 Try-in Paste Clear“, „Kuraray Noritake Dental Inc.“). Prieš aplikuojant silanizavimo medžiagą (CLEARFIL™ CERAMIC PRIMER PLUS (3 pav.), kurios sudėtyje yra 10-MDP, buvo įterpti retrakciniai siūlai, o restauracijų vidinis paviršius 20 sekundžių apdorotas 5 proc. vandenilio fluorido rūgštimi. Danties paviršius buvo 20 sekundžių ėsdinamas 33 proc. ortofosforo rūgštimi ir tada nuplautas. Ant danties užtepta praimerio, kurio sudėtyje yra 10-MDP („PANAVIA™ V5 Tooth Primer“ (4 pav.), ir išdžiovinta pagal gamintojo instrukcijas. Tuomet aplikuota laminačių cemento („PANAVIA™ Veneer LC Paste Clear“) (5 pav.) ir uždėta laminatė. Cemento perteklius buvo tirštas ir tinkamai išlaikė laminatę savo vietoje, kol buvo vykdomos visos kraštų tikrinimo procedūros ir prieš trumpą 1 sekundės pakietinimą (6 pav.).

3 pav. CLEARFIL™ CERAMIC PRIMER PLUS, aplikuojamas ant laminačių vidinių paviršių

4 pav. „PANAVIA™ V5 Tooth Primer“ aplikavimas ant ėsdintų danties paviršių

5 pav. „PANAVIA™ Veneer LC Paste Clear“ aplikuojama ant paruoštų vidinių laminačių paviršių

6 pav. „PANAVIA™ Veneer LC Paste“ iš karto uždėjus. Atkreipkite dėmesį į klampią, tirštą cemento konsistenciją, dėl kurios pastą lengva pašalinti tiek drėgnos, tiek gelio fazės.

Cementas perėjo į gelio fazę, o tai palengvino cemento pertekliaus pašalinimą ir valymo procedūra buvo minimali (7 pav.). Prieš galutinę kietinimo procedūrą, siekiant pašalinti deguonies inhibicinį sluoksnį, kraštai buvo padengti skaidriu glicerino geliu (8 pav.).

7 pav. Cemento pertekliaus šalinimas pakietinus 1 sekundę

8 pav. Galutinis laminačių gomurinio ir lūpinio paviršių kietinimas vienu metu

Kraštai buvo užbaigti ir nupoliruoti, kad kuo labiau blizgėtų, o restauracijų okliuzija patvirtinta kaip tinkama. Iš pooperacinių vaizdų matyti puiki estetinė kraštų integracija (9 pav.).

9 pav. Pooperacinė estetinė 1.2 ir 2.2 laminačių integracija

Atliekant pakartotinį vertinimą pagal naudojant poliarizacinius filtrus padarytą nuotrauką, nustatyta, kad restauracijos į naują šypseną integruotos estetiškai ir funkcionaliai (10 pav.). Dabar planuojama estetinė 2.3 danties augmentacija, kad dantis atitiktų kontralateralinį iltinį dantį.

GALUTINĖ SITUACIJA

10 pav. Galutinis rezultatas naudojant poliarizacinius filtrus pakartotiniam įvertinimui atlikti

Dentist:

CLARENCE TAM

References

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

Case by Martin Laurik, MDT

There are so many different restorative materials out there and so many design and finishing concepts available that it often seems difficult to select the best option for a specific case. Using an allrounder like KATANA™ Zirconia YML can facilitate decision making: It is a great choice for single- to multi-unit restorations, works on teeth and implants alike, and can be adapted to individual needs by selecting a suitable design concept and adequate finishing technique. In this way, it is even possible to solve aesthetically challenging cases as the one illustrated below.

Initial situation and temporization

This patient was in need for treatment after the loss of her maxillary right central incisor and the placement of an implant in this region. As a replacement of the restorations on the other three maxillary incisors was necessary as well, it was decided to produce four crowns made of the same material – KATANA™ Zirconia YML. For aesthetic evaluation of the restorations’ length, angulations and shape in the mouth and a functional test drive, the crowns were digitally designed in full contour and milled from PMMA in the determined tooth shade A2 (Fig. 1).

Fig. 1. Full-contour PMMA crowns on the master cast.

Design, milling and effect dyeing of the zirconia crowns

Once the appearance and functional aspects of the temporary restorations were approved by the patient and the restorative team, the definitive crowns were produced. Their design was based on the full-contour design of the temporaries; however, a facial reduction of 0.6 mm was carried out by the software to create space for individualization with a small layer of veneering porcelain. The crowns were then milled from a KATANA™ Zirconia YML disc in the shade A1 – approximately one shade lighter than the determined tooth shade. To mask the uneven colour from the tooth stumps and the implant abutment, the intaglio of the crowns was treated with Esthetic Colorant in the shade Opaque. Some individual and intensified colour effects on the vestibular surface were also created with Esthetic Colorant.

Internal staining and porcelain layering

To slightly adjust the chroma and lightness, a first layer of CERABIEN™ ZR Internal Stains was added, followed by a wash bake. After the application of a first layer of CERABIEN™ ZR porcelains (Body, Enamel and Translucent) and baking (Fig. 2) – the central incisors received a layer of A1B, the lateral incisors a mixture of A1B and A2B (slightly darker to provide for a better match with the canines) with LT1, LT Natural completing the picture – additional internal staining was carried out (Fig. 3). The final layer of CERABIEN™ ZR luster porcelains (LT1, ELT2 used on the convex line angles to achieve an external reflection) was added and fixed in a fourth bake (Fig. 4).

After adjustments and very rough polishing, a self-glaze firing programme was selected (firing temperature 915 °C, holding time 5 seconds). On the highly polished incisal and palatal parts of the crowns and for contact point adjustment, CERABIEN™ ZR FC Paste Stain Glaze was applied and fixed with the same bake. The finished crowns on the model are shown in Figure 5, while Figure 6 displays the final treatment outcome.

Fig. 2. Crowns milled from KATANA™ Zirconia YML with a facial cutback of 0.6 mm after individualization with Esthetic Colorant, sintering, internal staining and the application of a first layer of porcelain.

Fig. 3. This picture shows the subtle internal stain adjustment to the ceramic mostly on the incisal part.

Fig. 4. Crowns prior to final shape adjustments and polishing.

Fig. 5. Finished crowns on the model.

FINAL SITUATION

Fig. 6. Treatment outcome.

Easy approach to beautiful restorations

The presented approach is a relatively easy way of producing highly aesthetic anterior restorations. Using an allrounder zirconia combined with a few selected effect liquids, internal stains and luster porcelains, it is possible to achieve a great optical integration even in a situation where teeth and implants need to be restored. The natural shape and surface texture of the restorations plays an important role in this context, as does the base material – a naturally shaded, highly translucent zirconia.

Dentist:

MARTIN LAURIK, MDT

Martin started working as a dental technician in 2014. In the time since, he never stopped training and learning from renowned colleagues. Continuing education courses focused on dental ceramics and occlusion in the functional concept of Slavicek. Fascinated by the beauty of natural teeth, developing an understanding of their complexity and learning how to mimic nature’s design as closely as possible has always been his primary goal, while he is well aware that there is still a lot to be learned and explored on the road to excellence.

Case by Dr. Jusuf Lukarcanin

Abrasion and shape correction was also the major reason for this 58-year-old female patient to ask for cosmetic dental treatment. She was unhappy with the appearance of the anterior teeth in the maxilla, which showed signs of tooth wear and discolouration. The selected treatment approach was composite veneering with CLEARFIL MAJESTY™ ES-2 Universal in the shade UD. The shade was selected based on the indication and the somewhat darker shade of the patient’s natural teeth.

Fig. 1. Initial clinical situation.

Fig. 2. Treatment outcome.

Reasons for selecting universal dark:

- For older patients (tooth shades A3 and darker)

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

Universal dark properties:

- High light scattering effect

- Well-balanced translucency

With PANAVIA™ SA Cement Universal and KATANA™ Zirconia

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

INITIAL FIT OF ABUTMENT & RESTORATION

Basic technique on the treatment of the abutment and restoration.

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

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

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

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

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

TREATMENT OF KATANA™ Zirconia RESTORATION WORKFLOW

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

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

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

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

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

Fig. 4. Seat restoration on abutment.

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

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

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

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

With PANAVIA™ SA Cement Universal

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

TREATMENT OF TITANIUM ABUTMENT

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

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

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

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

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

REFERENCE INDEX POINTS TO ENSURE ACCURATE SEATING

Fig. 1. Mark Index position on implant analog.

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

TREATMENT OF RESTORATION & BONDING TO THE ABUTMENT

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

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

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

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

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

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

Fig. 7. Wipe off remaining resin with gauze.

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

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

4 Clinical cases by Dr. Jusuf Lukarcanin

Composites with a universal shade concept, a reduced number of shades that may be selected without any shade guide are a clear trend in restorative dentistry. With specific blend-in properties, these materials can help streamline restorative procedures and reduce chair time, take some pressure off the dental practitioner and contribute to potentially good outcomes. Some users, however, are skeptical about a wide-scale use of the materials, particularly when it comes to restoring teeth in the anterior region. The reasons may be a comparatively high translucency requiring the separate application of a blocker (or opacious shade) in certain situations, or a too limited shade offering.

Personal experience shows that CLEARFIL MAJESTY™ ES-2 Universal is perfectly suitable for a wide range of single-shade restorations in anterior teeth. It offers great polishability and long-term gloss retention and is available in just four shades: One universal shade (U) originally designed for posterior restorations, universal light (UL) and universal dark (UD) as the two major options for anterior teeth and, finally, universal white (UW) for the imitation of any bleached shade. In general, all four options may be used in the anterior and posterior region. As the blend-in ability is due to proprietary light-diffusion technology and not managed via an increased translucency, the application of a blocker is usually not necessary and even larger areas can be restored quite inconspicuously.

For those asking themselves when to select which shade in the anterior region, the following clinical case examples and comments may provide some useful guidance. The recommendations and practical tips are based on personal experience. All patients were in treatment for diastema closure or shape correction, but the selection criteria are the same for other types of anterior restorations, too.

UNIVERSAL LIGHT: FOR NATURAL RESULTS IN BRIGHTER TEETH

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

Fig. 1. Initial situation.

Fig. 2. Initial situation: Deep bite.

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

Fig. 4. Immediate treatment outcome.

Reasons for selecting universal light:

- For younger patients (tooth shades A2 and lighter)

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

Universal light properties:

- High light scattering effect

- Well-balanced translucency

UNIVERSAL DARK: FOR NATURAL RESULTS IN DARKER TEETH

Abrasion and shape correction was also the major reason for this 58-year-old female patient to ask for cosmetic dental treatment. She was unhappy with the appearance of the anterior teeth in the maxilla, which showed signs of tooth wear and discolouration. The selected treatment approach was composite veneering with CLEARFIL MAJESTY™ ES-2 Universal in the shade UD. The shade was selected based on the indication and the somewhat darker shade of the patient’s natural teeth.

Fig. 1. Initial clinical situation.

Fig. 2. Treatment outcome.

Reasons for selecting universal dark:

- For older patients (tooth shades A3 and darker)

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

Universal dark properties:

- High light scattering effect

- Well-balanced translucency

UNIVERSAL: WHENEVER A HIGH TRANSLUCENCY IS DESIRED

In teeth in which the areas to be restored are surrounded by a lot of non-discoloured tooth structure - as may be the case in Class I, II and Class V cavities - the use of CLEARFIL MAJESTY™ ES-2 Universal in the shade U may be an option. The 28-year-old patient, who presented for diastema closure, had teeth with a comparatively low translucency and different shades due to smoking and excessive coffee consumption. As the composite was applied in enamel areas only, the relatively high translucency of the universal shade seemed beneficial in this case.

Fig. 1. Initial clinical situation.

Fig. 2. New smile of the patient.

Reasons for selecting universal:

- Large amounts of underlying or surrounding tooth structure present

- Medium light-scattering desired

Universal properties:

- High translucency

- Medium light-scattering effect

UNIVERSAL WHITE: FOR ALL PATIENTS ASKING FOR A BLEACHED EFFECT

For all cases that require a particularly bright tooth shade – e.g. children or patients with bleached teeth / asking for a bleached effect in their restorations – CLEARFIL MAJESTY™ ES-2 Universal in the shade UW is likely to be the first choice. The young patient aged 28 shown below asked for diastema closure including shape and shade correction: She wanted to have a brighter, more beautiful smile.

Fig. 1. Initial clinical situation.

Fig. 2. Shape and shade correction were desired in this case.

Fig. 3. Treatment outcome …

Fig. 4. … leading to the beautiful smile the patient desired.

Reasons for selecting universal white:

- Cases requiring a particularly high brightness or value

- Restorations in deciduous teeth

- Restorations in bleached teeth

Universal white properties:

- Well-balanced translucency

- High light-scattering effect

CONCLUSION

One universal composite, four shades: In the case of CLEARFIL MAJESTY™ ES-2 Universal, this portfolio is absolutely sufficient for single-shade restorations even in the aesthetically demanding anterior region. Properties such as a nice blend-in effect, a great polishability and gloss retention over time support dental practitioners in creating beautiful restorations. As shade determination may be based on very few criteria instead of a complex shade guide, the whole restoration procedure becomes less stressful and more efficient. Furthermore, with only four shades to stock and usually no blocker needed, the number of materials on stock is reduced, leading to facilitations in stock management as well.

Case report by Dr. Wissam Dirawi, DDS

During the last decade, zirconia has increasingly established itself as the material of choice in oral prosthodontic rehabilitation. Its great mechanical and inert properties are the main reason for this trend. Since the introduction of multi-layered zirconia blanks more than ten years ago, the optical properties have been improved dramatically. The multi-layered zirconia used nowadays (e.g. KATANA™ Zirconia YML from Kuraray Noritake Dental Inc.) offers well-balanced mechanical properties, translucency and colour. It allows dental technicians from all over the world to produce aesthetic full-contour restorations that are merely stained.

Even in the anterior region, stained monolithic restorations may be an option. Factors such as the age of the patient, the internal colour structure of the adjacent dentition, the number of teeth to be restored (one versus all four or six maxillary anterior teeth), the aesthetic demands of the patient and financial aspects should be taken into account in the material selection process. In the case described below, full-contour zirconia was selected for several reasons.

BACKGROUND

The 71-year-old female presented in the clinical due to aesthetic problems in the maxillary anterior region. Oral hygiene was good and the patient was a non-smoker. Infraposition of the existing implant-based crown (Nobel Biocare Brånemark RP fixture) in the position of the right central incisor (tooth #11 according to the FDI notation) was evident. Moreover, gingival retraction was observed on the maxillary right lateral incisor (tooth #12), while the left lateral incisor (tooth #22) has a major composite filling with discolouration. The patient expressed the desire to adjust the gingival level differences and to restore the four maxillary incisors with all-ceramic crowns for optimal aesthetics.

Fig. 1. Initial situation: Frontal view.

Fig. 2. Initial situation: Facial view.

Fig. 3. Initial situation: Occlusal view of the maxilla.

Fig. 4. Initial situation: Occlusal view of the mandible.

MATERIAL SELECTION

Due to the decision to restore all four anterior incisors, monolithic zirconia was a suitable material option. It would allow the team to obtain the desired results within the financial framework. In order to meet the aesthetic demands of the patient, provide for the required mechanical properties and allow for proper masking of the underlying structures, KATANA™ Zirconia YML was selected. It offers colour, translucency and flexural strength gradation throughout the multi-layered blank.

TREATMENT PROCEDURE: FROM PREP TO TEMPORIZATION

In order to design the indirect restorations, a digital impression was taken with an intraoral scanner and the data was transferred to the dental laboratory Teknodont in Malmoe, Sweden. There, a digital wax-up was created. After patient approval, a matrix was produced and sent to the clinic. Here, the old restorations were removed and the three maxillary incisors (all but the one replaced by an implant) prepared for full coverage restorations. A healing abutment was placed on the implant and a temporary bridge produced chairside using the matrix and Protemp 4 Temporization Material (3M) in the shade A3. Subsequently, a gingivectomy was carried out with a ceramic burr (Ceratip, Kt.314.016 – KOMET) in the buccal aspect of the left central and lateral incisor.

Fig. 5. Chairside-produced temporary in the patient’s mouth.

After the patient’s approval of the aesthetics, phonetics and function of the temporary restoration, the situation was captured with an intraoral scanner again. This allowed the team to duplicate the shape of the construction. Based on the acquired data, a new set of splinted temporary crowns made of PMMA (HUGE Multilayer PMMA) in the shade A3 was milled in laboratory. They were placed to allow the patient to further evaluate the aesthetic appearance and function for a couple of weeks. The patient was happy with the phonetics, function and appearance of the crowns, which were merely slightly too bright in comparison to the adjacent teeth, and approved the shape for the production of the permanent restorations.

Fig. 6. Printed model …

Fig. 7. … with splinted PMMA crowns.

Fig. 8. Lab-made temporary restorations.

Fig. 9. Long-term temporary in place: Lateral view from the right.

Fig. 10. Long-term temporary in place: Frontal view.

Fig. 11. Long-term temporary in place: Lateral view from the left.

FINAL RESTORATIONS: PRODUCTION AND CEMENTATION

Based on the dataset of the temporary restorations, four separate crowns – one implant and three tooth-based – were designed in full contour. Without any anatomical reduction, the restorations were milled from KATANA™ Zirconia YML. Based on the evaluation of the temporary restoration, the shade selected this time was A3.5. CERABIEN™ ZR FC Paste Stain was used for external staining and glazing of the surface. Still in the laboratory, the implant-based crown was cemented to the gold-shaded titanium abutment (Elos Medtech) with PANAVIA™ V5 (Kuraray Noritake Dental Inc.) in the shade opaque for an improved masking effect.

While the abutment crown was screwed onto the implant and the screw hole closed with composite, the three tooth-based crowns were placed using PANAVIA™ SA Cement Universal (Kuraray Noritake Dental Inc.).

Fig. 12. Final restorations on the model.

Fig. 13. Intraoral situation prior to restoration placement.

CONCLUSION

Multilayered zirconia is a suitable material for many clinical situations. Due to the availability of modern types of highly translucent, multi-layered blanks, it is possible to produce aesthetic outcomes even when using the material monolithically – not only in the posterior region, but also in the aesthetic zone in some indications. The present case shows that very good results and patient satisfaction can be obtained. And due to outstanding mechanical properties, these outcomes may be expected to last for a long time.

Fig. 14. Immediate treatment outcome: Facial view.

Fig. 15. Immediate treatment outcome: Frontal view.

Fig. 16. Immediate treatment outcome: Occlusal view.

References

- Alfadhli R, Alshammari Y, Baig MR, Omar R. Clinical outcomes of single crown and 3-unit bi-layered zirconia-based fixed dental prostheses: An up to 6- year retrospective clinical study: Clinical outcomes of zirconia FDPs. J Dent. 2022 Dec;127:104321.
- Le M, Papia E, Larsson C. The clinical success of tooth- and implant-supported zirconia-based fixed dental prostheses. A systematic review. J Oral Rehabil. 2015 Jun;42(6):467-80.
- Alammar A, Blatz MB. The resin bond to high-translucent zirconia-A systematic review. J Esthet Restor Dent. 2022 Jan;34(1):117-135.
- Sadowsky SJ. Has zirconia made a material difference in implant prosthodontics? A review. Dent Mat 2020; 36: 1–8.
- Mazza LC, Lemos CAA, Pesqueira AA, Pellizzer EP. Survival and complications of monolithic ceramic for tooth-supported fixed dental prostheses: A systematic review and meta-analysis. J Prosthet Dent 2022; 128: 566–74.
- Passia N, Mitsias M, Lehmann F, Kern M. Bond strength of a new generation of universal bonding systems to zirconia ceramic. J Mech Behav Biomed Mater. 2016; 62:268–274.
- Sailer I, Makarov NA, Thoma DS, Zwahlen M, Pjetursson BE. All-ceramic or metal-ceramic tooth- supported fixed dental prostheses (FDPs)? A systematic review of the survival and complication rates. Part I: Single crowns (SCs). Dent Mater 2015; 31:603-623.
- Pjetursson BE, Sailer I, Makarov NA, Zwahlen M, Thoma DS. All-ceramic or metal-ceramic tooth- supported fixed dental prostheses (FDPs)? A systematic review of the survival and complication rates. Part II: Multiple-unit FDPs. Dent Mater 2015; 31:624–639.

Case by Dr. Ioannis Memis

Single-shade or two-shade approach? Using modern resin composites, it is possible to treat virtually every patient in need of a direct restoration in an aesthetic way using one of those two techniques. If the defect is rather small, a single shade of composite restorative in a body opacity may be sufficient – especially when the tooth to be restored is in the posterior region. Larger defects and those located in the aesthetic zone may require a combination of two different shades – one as a dentin replacement and one as translucent as enamel – to closely imitate the optical characteristics of the natural tooth.

With CLEARFIL MAJESTY™ ES-2, Kuraray Noritake Dental Inc. offers a complete composite system designed to simplify procedures in bot, the single-shade and the two-shade approach. CLEARFIL MAJESTY™ ES-2 Classic is a typical composite for the single-shade technique consisting of 18 shades offered in a single universal opacity. Shade determination is brightness-based, meaning that the brightness is selected first and the hue and colour saturation in a second step (using the VITA Classical A1 – D4 shade guide). For those who want to skip shade determination completely, CLEARFIL MAJESTY™ ES-2 Universal has been introduced. It consists of only two shades for the anterior and one shade for the posterior region, selectable without using shade tabs. For the two-shade technique, CLEARFIL MAJESTY™ ES-2 Premium is the solution: It allows users to copy natural enamel and dentin layers with a total of seven enamel, seven dentin and four translucent shades. Its exceptional feature: pre-defined colour combinations with one Premium shade combination covering three VITA Classical shades. A natural blending into the environment is achieved with the Light Diffusion Technology in the formulation.

All three versions of CLEARFIL MAJESTY™ ES-2 are compatible with each other and offer the same favourable handling properties. The use of different techniques, shades and opacities is demonstrated using the following patient case.

YOUNG PATIENT WITH MULTIPLE CARIOUS LESIONS

A 24-year-old female patient was referred from undergraduate clinic of Operative Dentistry of the Aristotle’s University of Thessaloniki - School of Dentistry (Greece). Patient presented multiple interproximal carious lesions in need of restorative treatment. In the clinical and radiographic examination, the following defects were identified:

Quadrant 1 (maxillary right):

- Distal lesion on the lateral incisor (Class III)

- Mesial and distal lesions on the first premolar (Class II)

- Mesial and distal lesions on the second premolar (Class II)

- Mesial lesion on the first molar (Class II)

Quadrant 2 (maxillary left):

- Distal lesion on the lateral incisor (Class III)

- Mesial lesion on the first premolar (Class II)

- Mesial and distal lesions on the second premolar (both Class II)

- Mesial lesion on the first molar (Class II)

Quadrant 3 (mandibular left):

- Distal lesion on the first molar (Class II)

- Mesial lesion on the second molar (Class II)

In a stepwise procedure, the teeth were restored with CLEARFIL MAJESTY™ ES-2 either in a single-shade or in a two-shade approach depending on the size of the lesions.

INITIAL SITUATION

Fig. 1. Initial situation: Frontal view.

Fig. 2. Occlusal view of the maxilla.

Fig. 3. Occlusal view of the mandible.

RESTORING THE TEETH IN QUADRANT 1

The six carious lesions in this quadrant were restored in three steps. At first, the focus was on the first molar and second premolar. Opening the larger cavity mesially of the first molar provided access to the smaller lesion on the premolar’s distal surface. After caries excavation and cavity preparation, rubber dam was placed and fixed with a clamp on the second molar. The enamel in the cavities was treated with phosphoric acid etchant for 15 seconds before CLEARFIL™ Universal Bond Quick (Kuraray Noritake Dental Inc.) was applied according to the manufacturer’s instructions. For a morphologically correct designing of the proximal contact point and area, the use of a sectional matrix system with rings was utilized. Both cavities were restored with CLEARFIL MAJESTY™ ES-2 Premium in the shades A3D and A2E. Finishing and polishing of the occlusal surface accomplished with silicon cups and Twist Dia disks on a slow speed handpiece.

In the second step, the distal lesion on the first and mesial lesion on the second premolar were restored in an identical procedure with CLEARFIL MAJESTY™ ES-2 Premium in the shade A3D and CLEARFIL MAJESTY™ ES-2 Classic in the shade A3. A different approach was selected in step 3 for the lesions on the distal part of the lateral incisor and the mesial part of the first premolar. Due to the small size and the all-but-prominent position of the lesions, a single-shade technique using CLEARFIL MAJESTY™ ES-2 Classic in the shade A3 was selected. Between the lateral incisor and canine, a posterior sectional matrix was placed in an upright position and fixed with a wedge to support a proper restoration of the contact point, while both elements were used in the usual way between the canine and first premolar.

Fig. 4. Simultaneous restoration of the mesial lesion on the first molar and the distal lesion on the second premolar with CLEARFIL MAJESTY™ ES-2 Premium.

Fig. 5. Restoration of the distal lesion on the lateral incisor and the mesial lesion on the first premolar with CLEARFIL MAJESTY™ ES-2 Classic.

RESTORING THE TEETH IN QUADRANT 2

For the small disto-palatal lesion on the maxillary left lateral incisor, a single-shade technique with CLEARFIL MAJESTY™ ES-2 Classic in the shade A3 also produced aesthetic outcomes. The four lesions at the posterior region of the quadrant were restored in two steps – one for each pair of proximal lesions – with a combination of CLEARFIL MAJESTY™ ES-2 Premium in the shade A3D and CLEARFIL MAJESTY™ ES-2 Classic in the shade A1.

Fig. 6. A single-shade technique is sufficient to aesthetically restore this small lesion on the left lateral incisor.

Fig. 7. Simultaneous restoration of the mesial lesion on the second premolar and the distal lesion on the first premolar.

Fig. 8. Simultaneous restoration of the mesial lesion on the first molar and distal lesion on the second premolar.

RESTORING THE TEETH IN QUADRANT 3

In this quadrant, only a single pair of proximal lesions needed treatment. A simultaneous restoration procedure was selected once again due to the favourable space conditions. Although the size of the lesion was like those in the posterior region of the maxilla, a single-shade restoration was selected with the use of CLEARFIL MAJESTY™ ES-2 Classic (shade A3).

Fig. 9. Treatment of the lesions in quadrant 3.

CONCLUSION

In the present patient case, several different shades, opacities, and combinations of CLEARFIL MAJESTY™ ES-2 were utilized either in a single- or in a two-shade approach. All combinations and techniques produced good outcomes. As shown in Figure 4, the enamel opacity of CLEARFIL MAJESTY™ ES-2 Premium is visibly more translucent than the universal opacity of CLEARFIL MAJESTY™ ES-2 Classic. Experience shows that enamel shades translucency is highly valuable for aesthetic anterior restorations, while in posterior restorations, the universal shade approach is aesthetically adequate, particularly for medium-sized restorations, as shown in Figure 9. This is clearly an evidence of Light Diffusion Technology which is blending hue and colour saturation to the surrounding tooth structure.

Handling of all selected composite pastes is comfortable: non-sticky, adaptable to cavity walls and allowing precise occlusal sculpting. Polishing with Silicone Cups and TWIST DIA for Composite is easy, quick and leaves a natural gloss on the surface.

Case by Kosti 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.

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.

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.

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.