PMC4609806_01
Initial situation with insufficient cast partial crowns on teeth 45 and 46.
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For these restorations, repeated clinical intervention had been necessary due to the loss of retention and secondary caries (Figure 1).
Clinical situation after removal of restoration and caries.
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After the application of local anesthetics (UltraCain DS, Sanofi Aventis, Frankfurt, Germany), the existing posterior crowns were detached, and the caries was completely removed (Figure 2).
Preparation of teeth for digital impression-taking. After application of the retraction cords, a top layer of cotton coil impregnated with epinephrine for hemostasis is applied.
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Finally, a top layer of cotton coil impregnated with epinephrine for hemostasis (Gingi-Pak, Belport Company, Camarillo, USA) was looped around the tooth (Figure 3).
Detailed views of the intraoral scanning process and the measuring function for the substance reduction after digital bite registration.
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A buccal scan was taken when the patient closed into an intercuspal position (Figure 4).
Virtual design of the working models (Model Builder 2013, 3 Shape, Copenhagen, Denmark).
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Generatively manufactured working model.
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Dental models made of a beige high-performance resin (80-84 Shore D) were produced in a generative manufacturing process (LED-scanning technology based on STL files) and returned to the dental laboratory within 48 hours (Figures 6(a) and 6(b)).
Construction of monolithic crown and partial crown restorations with CAD software (DentalDesigner 2013, 3 Shape, Copenhagen, Denmark).
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After exploring the STL files for the production of the working models, the design process for the fully anatomic restorations was initiated with a CAD software package (DentalDesigner 2013, 3 Shape, Copenhagen, Denmark) (Figure 7).
ZLS crown and partial crown directly after the milling process.
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Removal of the fixation pin and shaping of the ground ceramic restorations with water-cooled diamond instruments.
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Afterward, the occlusal surfaces were also reworked with water-cooled diamond instruments (Figures 9(a) and 9(b)).
Individual coloring of the crystallized ZLS restoration with special staining liquids.
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After the first crystallization firing, the restorations were further individualized by using two layers of stains in two separate firing cycles at 800 C (Figure 10).
Final polishing.
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The restorations were then mirror-finished with diamond-impregnated silicone instruments and polishing pastes (Figure 11).
Final fit checking with proximal and occlusal contacts on the digitally fabricated working model.
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Finally, occlusion and proximal contacts were checked and adjusted on the digitally fabricated working models (Figure 12).
Occlusal adjustments of the restoration during try-in with a fine-grit-size diamond instrument (8390.314.016, Gebr. Brasseler, Lemgo, Germany).
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Brasseler, Lemgo, Germany) (Figure 13).
Conditioning of the cementation surface with 5% hydrofluoric acid for 20 seconds.
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Polishing Set Clinical, Vita Zahnfabrik, Bad Sackingen, Germany). Prior to adhesive luting, the restoration surfaces intended for bonding were conditioned with 5% hydrofluoric acid (Vita Ceramics Etch, Vita Zahnfabrik, Bad Sackingen, Germany) for 20 seconds (Figure 14).
Application of silane on the cementing surfaces after conditioning with 5% hydrofluoric acid.
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After drying the etched restorations, a silane material (Calibra Silane, Dentsply DeTrey, Konstanz, Germany) was applied (residence time: 1 minute) (Figure 15).