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32 Dental Tribune Middle East & Africa Edition | July-August 2015cad/cam MU Dr Petr Hajný Nerudova 9 118 00, Prague 1 Czech Republic cerec.hajny@email.cz Contact Information Monolithic brothers By MU Dr. Petr Hajný, CZ P atients who visit the dentist with the wish to have their smile enhanced would like this to happen in a fast, efficient and complication-free manner. Esthetic and functional rehabili- tation of the anterior dental arch and occlusal height CAD lithi- um disilicate ceramics (LS2 can be completed in a single day us- ing IPS e.max®) in combination with CAD/CAM technology (the CEREC® system by Sirona, Ger- many, was used here). We use T-Scan® technology (Tekscan, USA) to assess the articulation and this method has enabled us to achieve excellent results. Until recently, closing lateral gaps in patients refusing to un- dergo implant treatment posed a problem with timescales for us. Zirconia bridges have become the solution for these cases. To be able to treat our patients within a few hours, but at the longest within 48 hours, we were looking for possibilities of speeding up, or simplifying, this treatment modality. After con- sidering the results of scientific studies investigating the surface properties and wear of various polished monolithic ZrO2 resto- rations, we decided that the Ze- notec® CAD/CAM system from Wieland would be appropriate for this purpose. This system al- lows us to mill even extensive bridges from zirconia. Case presentation The patient in this case was a 60-year-old lady whose dentition hadbeenrestoredwithmetalce- ramic crowns in the anterior and bridges in the posterior region. Her main complaint was the col- our and length of the teeth. Her teeth were completely invisible during both speaking and smil- ing (Figs 1 to 3). She wished to have a bright smile that was the colour of “Hollywood white”. She refused to have any im- plant therapy to close the gaps in the posterior region. For this reason, we chose to use all-ce- ramic bridges. The plan was to manufacture a bridge spanning from tooth 23 to 26, a cantilever bridge from tooth 33 to 35 with a pontic at 36 and a bridge from tooth 45 to 47. The gingival tissues were in poor condition and this was mainly attributed to the impact of the metal ceramic restora- tions. Figure 4 shows the need for increasing the vertical di- mension. Material selection On the basis of a bleach shade guide, the patient decided in favour of the BL2 bleach shade and did not want this shade to be tuned down with materials of a darker hue. We therefore decided to use the unstained, or pure, shade variant for the fabri- Fabricating individualized monolithic restorations using IPS e.max CAD LS2 and Zenostar ZrO2 cation of the Zenostar® bridges and IPS e.max CAD LT blocks in the BL2 bleach shade (Fig. 5). Usually, we use IPS e.max CAD for the fabrication of three-unit bridges up to the second premo- lar. The present case, however, required four-unit bridges and a cantilever bridge in the posterior region; IPS e.max CAD does not cover these indications. Clinical procedure After the existing restorations had been removed, FRC Postec glass-fibre reinforced composite root canal posts were inserted into teeth 21, 23, 35, 44 and 45, followed by the placement of MultiCore® Flow core build-up composite. Next, we replaced all existing single restorations with crowns made of IPS e.max CAD using the CEREC MCXL CAD/ CAM system and IPS e.max CAD LT blocks in shade BL2 (stain- ing technique). The occlusal height was raised at the same day and temporarily stabilized with Telio® CAD bridges. The lower anterior teeth were re- stored with laminate veneers made of IPS e.max CAD (stain- ing technique). Prior to placing the Telio CAD bridges with Telio CS Link, impressions were tak- en (Virtual® 380). A bite record of the new vertical dimension as taken using Virtual CADbite sili- cone material. The bridges were manufactured using a Wieland® scanner and a Zenotec mini milling unit. The restorations were designed with 3Shape® software (Figs 6 to 8). To recon- struct the bridge from tooth 23 to 26, the canine, the first premo- lar and the second premolar of the first quadrant were mirrored while the first molar was recon- structed on the basis of data re- trieved from the 3Shape library. Fig. 1. Before: view of the lips Fig. 2. OptraGate® Fig. 3. Before: lateral view with OptraGate Fig. 5. Wieland work station and ZrO2 block Fig. 6. Design of the bridge 23 to 26 in the 3Shape software Fig. 7. Design of the cantilever bridge from tooth 33 to 35 with a pontic at 36 and a bridge from tooth 45 to 47 Fig. 8. Virtual articulation to estab- lish the functional characteristics Fig. 4. Clinical situa- tion after removal of maxillary crown Fig. 8. Virtual articulation to estab- lish the functional characteristics Fig. 10. Monolithic restorations after eleven months: IPS e.max CAD restorations and Zenostar Zr Fig. 11. Anterior view of the rehabili- tation Fig. 12. View of the lips: The patient is pleased with the outcome. Her wish has been fulfilled. Fig. 13. Close-up of the monolithic IPS e.max CAD crowns fabricated using the staining technique The contours of the molar were from the beginning very clear and detailed. There was no need for additional manual fissure adjustment. The restorations were milled, sintered in a Pro- gramat® S1 furnace and then customized applying stains from the Zenostar Art Module in the staining technique. Finally, the occlusal contact points were pol- ished (Fig. 9). Final seating On the second day, the tempo- rary Telio CAD bridges were removed and the teeth were cleaned with chlorhexidine- containing Cervitec® Liquid mouth rinse. Try-in was carried out without any problems; ad- ditional adjustments were not required. The restorations were cleaned with Ivoclean® and then silanized with Monobond® Plus. The preparations were pretreat- ed with Multilink® Automix Primer A + B and then seated using Multilink Automix luting composite (yellow shade). After the luting composite had been pre-cured with a Bluephase® curing light and excess material removed, the restorations were permanently cemented in place activating the Turbo mode of the curing light a number of times. Articulation and occlusal con- tact points were assessed with a T-Scan device and then the occlusal surfaces were polished (Figs. 10 and 11). Conclusion A slight difference in brightness between the Zenostar zirconia bridges and the IPS e.max CAD crowns can be noted. With hind- sight, we would adjust the shade of the Zenostar framework with Zenostar Color Zr colouring solution before conducting the sintering process to adapt the brightness level in such cases. As an alternative, a pre-shaded block could be used instead of adjusting the shade later on by means of the staining technique. For the patient, her new bright smile was simply a wish fulfilled (Figs. 12 and 13). From our point of view, the 3Shape soft- ware enabled us to complete this rehabilitation in an efficient manner. The tooth shapes were easy to copy. An initial proposal for the design of the occlusal surface of the posterior teeth was immediately available and could be quickly and predict- ably adjusted. The restorations showed a smooth surface and clearly contoured fissures both on the screen and after milling in the 4-axis milling unit. We were able to seat the restora- tions straightaway as further adjustments were not necessary. Monolithic zirconia restorations have shown similar, if not lower, levels of enamel wear on antag- onists as other ceramic restora- tions in clinical applications. By using monolithic restorations, we are able to complete certain cases in a single day. If we look at recent investigations that evalu- ated the enamel wear caused by monolithic zirconia crowns and other ceramic materials and compared these results with the enamel wear caused by natural antagonists, we may conclude that we chose a functional and sensible solution [Enamel wear caused by monolithic zirconia crowns after 6 months of clinical use – T. Stober, J.L. Bermejo, P. Rammelsberg, M. Schmitter]. 11800, Prague 1