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I 39 industry report _ IPS e.max CAD LT I CAD/CAM 1_2011 _Clinical case study Tooth #25 of a 32-year-old female patient was restored with a crown owing to extensive destruc- tionofthedentalhardtissue(Fig.1).First,thetooth was prepared with a shoulder of approximately 1.0 mm in width (epigingivally). Subsequently, the preparation was dusted with IPS Contrast Spray and a digital impression was taken with the CEREC Bluecamcamera(Sirona).ThenewCERECsoftware (version 3.80) generates a visual image of the an- tagonists,whichreplacesthecentricbiterecord.In order to match the upper and lower teeth, an im- age of the centric situation is captured from the buccalaspect(Fig.2).Theupperandlowerteethare matched semi-automatically (Fig. 3). The 3.80 ver- sion is capable of designing biogeneric occlusal surfaces for full crowns. The software provides a design proposal for the tooth morphology, which isbasedontheocclusalsurfaceofthedistalneigh- bouring tooth and the antagonist (Fig. 4). The im- age of the bucco-oral cross-section of the crown allows the user to check the minimum occlusal thickness of 1.5 mm (Fig. 5). The minimal densifi- cation of the ceramic (0.2 vol%) during the crys- tallisation process is taken into account by the software and adjusted accordingly. After the crown had been milled, the proximal and occlusal contacts were adjusted on the patient (Figs.6&7).Inthiscase,the‘white’and‘crème’ma- terials from the corresponding stains assortment (IPS e.max CAD Crystall./Stains) were sparingly applied to the cusp tips and the ‘sunset’ material to the tooth neck and in the fissures. Immediately afterwards, a glaze in spray form (IPS e.max CAD Crystall./Glaze Spray) was applied to the outer surfaces of the crown. The spray was applied sev- eral times. Once the restoration had been fully coated with a white-opaque glaze layer, the crown was fired in a combined crystallisation and firing process in the Programat CS furnace (Figs. 8 & 9). Before the restoration was cemented in place, the inner surface of the crown was etched with 4.9 % hydrofluoric acid (IPS Ceramic Etching Gel) for 20 seconds. Subsequently, it was silanised for 60seconds(MonobondPlus).Thecrownlumenwas filled with the self-adhesive SpeedCEM. Next, the crown was securely seated on the prepared tooth by applying even pressure (Fig. 10). The cement residuewaspolymerisedforonesecondpersurface (mesio-oral, disto-oral, mesiobuccal, distobuccal) with a curing light (bluephase in the low-power mode) at a distance of about 5 mm. In this cured state, the cement was removed with great care using a scaler and a probe. The cement was fully cured with the bluephase in the high-power mode. Subsequently,thecementmarginwaspolished.The final inspection revealed the restoration to be in harmony with the overall situation (Figs. 11 & 12)._ Fig. 6_Occlusal view of the crown in the ‘blue’ state during try-in, before crystallisation firing. Fig. 7_Buccal view of the crown in the ‘blue’ state during try-in, before crystallisation firing. Fig. 8_Occlusal view of the crystallised and glazed crown on tooth #25. Fig. 9_Buccal view of the crystallised and glazed crown on tooth #25. Fig. 10_Cementation of the crown with the dual-curing, self-adhesive luting composite SpeedCEM. Fig. 11_Buccal view of the crown seated with a self-adhesive luting cement after the clean-up of excess. Fig. 12_Occlusal view of the crown seated with self-adhesive luting composite. Fig. 12 Dr Andreas Bindl Station für Zahnfarbene & Computer-Restaurationen Praxis am Zürichberg Attenhoferstrasse 8a 8032 Zurich Switzerland andreas.bindl@bluewin.ch CAD/CAM_contact Fig. 11Fig. 10 Fig. 9Fig. 8Fig. 7Fig. 6