Daniele Rondoni

Case by CDT Daniele Rondoni

When planning to replace Class II restorations, many things need to be considered. In order to select the most appropriate restorative technique and preparation design, it is essential to evaluate the amount and state of the remaining tooth structure, first. After repeated restoration replacement or in teeth originally restored with amalgam, for example, the remaining walls and cusps are often weakened and prone to fractures and cracks. When the cavity walls appear to be too thin or the structure is weak at the time of restoration replacement, it may be better to remove walls and cusps and opt for indirect adhesive restorations (overlays) instead of direct composite restorations. Due to favourable material properties – in particular a high flexural and compressive strength while being gentle to the opposing dentition and not too rigid for the surrounding tooth structures – we often opt adhesive restorations made of KATANA™ AVENCIA™ Block in those situations.

The following clinical case is used to describe the replacement of two composite restorations with overlays made of the innovative hybrid ceramic material.

Fig. 1. Initial clinical situation with composite restorations on the second premolar and first molar in need of replacement. The tooth structure particularly of the first molar was weak, with the distobuccal cusp already fractured.

Fig. 2. Prepared tooth structure ...

Fig. 3. Restorations milled from a KATANA™ AVENCIA™ Block after high-gloss polishing and characterization.

Fig. 4. Finalized restorations on a resin model.

Fig. 5. Adhesively cemented restorations in the patient’s mouth.

FINAL SITUATION

Fig. 6. Treatment outcome with a nice transition from the tooth structure to the restoration.

EKSEMPEL FRA CDT DANIELE RONDONI

Sædvanligvis kan det æstetiske potentiale i et dentalkeramisk materiale – specielt dets translucens – kun øges på bekostning af en nedsat bøjestyrke. Derfor har der manglet højtranslucente materialer, der er egnede til fremstilling af smukke monolitiske restaureringer, i form af lange broer. Lanceringen af dental zirkonia med forskellige niveauer af translucens og styrke i en enkelt disk har ændret på denne situation.

KATANA™ Zirconia YML fra Kuraray Noritake Dental Inc. er et sådant materiale. Det har en flerlagsstruktur med en høj bøjestyrke på 1.100 MPa, en høj chroma og en reduceret translucens i den nederste halvdel af disken. Selvom bøjestyrken og chroma er reduceret i den øvre del af disken og de incisale områder, øges materialets translucens opefter, ligesom i naturlige tænder. Dette giver et ubegrænset indikations-spektrum – forudsat at nogle design- og positioneringsregler overholdes. For at undersøge, om disse regler begrænser tandteknikerens designfleksibilitet, og om det æstetiske potentiale er højt nok til monolitiske anteriore restaureringer, har vi grundigt gennemtestet materialets bearbejdningsmæssige og optiske egenskaber. Følgende kliniske eksempel giver læserne et indblik i,
hvad der er muligt med dette innovative, flerlagede materiale.

Fig. 1. KATANA™ Zirconia YML 4- og 6-leddede broer efter fræsning og sintring. En naturlig facial overfladetekstur spiller en afgørende rolle, når der skal skabes
æstetiske monolitiske restaureringer.

Fig. 2. Okklusal visning af de to monolitiske broer. Den linguale overflades design sikrer gode muligheder for at opretholde god mundhygiejne.

Fig. 3. En lyskilde bag restaureringerne afslører den incisale translucens.

AFSLUTTENDE SITUATION

Fig. 4. Bukkal visning af den færdige 6-leddede bro, cementeret i patientens mund.

Fig. 5. Bukkal visning af den færdige 4-leddede bro, cementeret i patientens mund.

Med denne nye type af flerlaget zirkonia, er det muligt at producere æstetiske monolitiske restaureringer velegnet selv til brug i det anteriore område. Materialet byder på en høj designfleksibilitet trods dets graduerede styrke, og den høje translucens i incisalområdet sørger for et naturligt udseende efter sintring. Ultra-mikrolag og glasur på den monolitiske overflade vil være tilstrækkeligt til at levere resultater som kan tilfredsstille vores patienter.

DANIELE RONDONI, MDT

Born in Savona in 1961 where he lives and has worked in his own laboratory since 1982 with his collaborators. Graduated from the dental technician school IPSIA “P. Gaslini” in Genoa in 1979. He continued his education by attending relevant workshops for the “Italian dental school“ and broadened his professional experience in Switzerland, Germany and Japan. Since 2011 Kuraray Noritake Dental International Instructor.

By Daniele Rondoni, RDT

Considering different criteria to select the ideal zirconia and frame design to meet the level of esthetics requested.

Step 1
Final Preparations.

Step 2
Zirconia Frame (KATANA Zirconia STML A2) cut-back designed to reproduce translucent incisal area.

Step 3
Application of 1st Internal Stain and firing.

Step 4
Application of 1st Luster, Clear Cervical and firing.

Step 5
Application of 2nd Internal Stain and firing.

Step 6
Application of 2nd Luster, and Opacious Body.

Step 7
Completion of firing.

Step 8
Completion of morphological correction.

Step 9
Post-operative view.

By Daniele Rondoni, RDT

Preoperative view

1 PFM. 3 Laminates on refractory

Postoperative view

NORITAKE SUPER PORCELAIN EX-3 CHROMATIC MAP