Initial situation and temporisation

This patient required treatment after the loss of her maxillary right central incisor and the placement of an implant in this region. Given that a replacement of the restorations on the other three maxillary incisors was necessary, it was decided to produce four crowns made of the same material, KATANA Zirconia YML. For aesthetic evaluation of the restorations’ length, angulation and shape in the mouth and a functional try-in, the crowns were digitally designed in full contour and milled from PMMA in the determined tooth shade (A2; Fig. 1).

Design, milling and effect staining of the zirconia crowns

Once the appearance and functional aspects of the temporary restorations had been approved by the patient and the restorative team, the definitive crowns were produced. Their design was based on the full-contour design of the temporary restorations; however, a facial reduction of 0.6 mm was carried out by the software to create space for individualisation with a thin layer of veneering porcelain. The crowns were then milled from a KATANA Zirconia YML disc in 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 (Kuraray Noritake Dental) 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 (Kuraray Noritake Dental) was added, followed by a wash bake. A first layer of CERABIEN ZR Body, Enamel and Translucent porcelains and CERABIEN ZR Luster porcelains was then applied and baked (Fig. 2), the central incisors receiving a layer of Shade A1B and the lateral incisors a mixture of Shades A1B and A2B (slightly darker to provide for a better match with the canines) with Shade LT1, finished with Shade LT Natural. Additional internal staining was then carried out (Fig. 3).

The final layer of CERABIEN ZR Luster porcelains (Shades LT1 and ELT2, used on the convex line angles to achieve external reflection) was added and fixed in a fourth bake (Fig. 4).

After adjustments and very rough polishing, a self-glaze firing program 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 using the same program (Fig. 5).

Easy approach to beautiful restorations

The presented approach is a relatively easy way of producing highly aesthetic anterior restorations (Fig. 6). Using an all-rounder zirconia combined with a few selected effect liquids, internal stains and lustre porcelains, it is possible to achieve excellent optical integration even in a situation where both teeth and implants need to be restored. The natural shape and surface texture of the restorations play an important role in this context, as does the use of a naturally shaded, highly translucent zirconia as a base material.