18 ◊Page 17 CAD/CAM Dental Tribune Middle East & Africa Edition | 3/2020 Fig 13 Fig 14 Figs. 13 and 14: Final restorative result after adhesive cementing Fig. 15: Preoperative smile and lip profile Fig. 16: Postoperative smile and lip profile treatment of tooth 34 was adequate, while tooth 46 required a primary endodontic treatment due to a ir- reversible pulpitis. All other teeth were vital and free of symptoms. The periodontal findings showed moder- ate gingivitis (periodontal screening index < 3 in all sextants). Teeth 13, 23, 24, and 43 additionally exhibited ves- tibular gingival recessions. In addition to an oral rehabilitation, the patient also wanted to improve her anterior tooth aesthetics. She first received extensive oral hy- giene instructions and professional tooth cleaning. The insufficient res- torations on teeth 24, 25, 26, 27, 35, 37, and 47 were replaced by call restora- tions (Luxacore; DMG, Hamburg, Germany) that were adhesively cemented (OptiBond FL; Kerrhawe SA, Bioggio, Switzerland). Teeth 38, 48 and the class V cavities of teeth 24 and 33 were definitely restored by direct composite fillings (Venus; Heraeus Kulzer, Hanau, Germany). The gingival recessions on teeth 13 and 23 were not surgical covered because a sufficient amount of at- tached gingiva was present and no further progression was observed. In addition, the patient had a low smile line, meaning that this posed no aes- thetic problems. A formal treatment plan and cost estimate was provided and checked by a dental expert of the patient’s health insurer. The following meas- ures were approved: Crown restora- tions for teeth 11, 21, 22, 24, 25, 26, 27, 35, 37, and 47 plus a remake of bridge 17–14. The functional pretreatment was performed with the aid of a centric splint in the maxilla which simulat- ed a bite raised by 2mm. The patient did not show any symptoms of my- oarthropathy or craniomandibular dysfunction after establishing her new vertical dimension of occlusion. In a first prosthetic treatment step, the posterior teeth were supplied with crowns (teeth 14, 26, 27, 37, and 47) and a bridge (teeth 17–15) in ve- neered zirconia. Teeth 32–42 were bleached and their incisal edges clinically lengthened by means of direct composite restorations (Es- sentia and G-Premio Bond; GC, Bad Homburg, Germany) in order to obtain a uniform aesthetic result. Within the framework of the Cel- tra Campus Challenge, the patient could be offered a cost-effective and aesthetic treatment offer upper jaw: Teeth 21 and 22 were restored with crowns and teeth 11, 12, 13, and 23 with veneers. In addition, teeth 24 and 25 received partial crowns. For the plan- ning of the ceramic restorations, a wax-up was created and developed into a composite mock-up (Figs. 3 and 4) (Luxatemp; DMG). The tooth shade (A2) was selected based on the Vita Classic shade guide (Vita, Bad Säckingen, Germany). AD The preparations (Fig. 5) followed the preparation guidelines for all- ceramic restorations1 and the ap- propriate minimum wall thickness requirements for lithium silicate ce- ramic restorations. The preparation for the partial crowns 24 and 25 had rounded interior line angles and a 90° shoulder at the preparation mar- gin. To prepare for the veneers (13, 12, 11, 23), approximately 0.5–0.7mm of hard tissue was removed on the labial aspect and a 0.5mm chamfer provided (Fig. 6). The intact proxi- mal surfaces remained untouched. Otherwise, the teeth were prepared for circular full veneers (“360-degree veneers”). The crowns of teeth 21 and 22 were prepared with a 1-mm circu- lar shoulder. Reduction of the incisal edges could be dispensed with as a consequence of raising the bite by 2mm. A conventional impression was tak- en of the prepared teeth and the casts were scanned. Prior to taking the im- pression, retraction cords (UltraPak; Ultradent, South Jordan, Utah, USA) were placed for gingival retraction around the prepared teeth. Retained proximal contacts were separated with thin matrix strips. The impres- sion was taking using and addition- type silicone at one time and in two phases (Aquasil; Dentsply Sirona Re- storative) (Fig. 7). The conventional impressions and casts facilitated the digital design process by providing a laboratory-made wax-up and sub- sequent adjustment of the restora- tions. This meant that hardly any intraoral adjustments were required. A vacuum-formed splint (Erkodent, Pfalzgrafenweiler, Germany) was first made with the aid of the wax-up, allowing provi- sional resin restorations to be pro- duced (Luxatemp; DMG). These were subsequently connected to the pre- pared teeth with Prime & Bond XP (Dentsply Sirona Restorative) and a flowable composite (Baseliner; Her- aeus Kulzer). transparent The restorations themselves were produced using the CEREC CAD/ CAM (Dentsply Sirona, Bensheim, Germany). To this end, the saw-cut models were scanned with a Blue- Cam (Dentsply Sirona) (Fig. 8). The teeth of the wax-ups were copied digitally and used for the design of the restorations (CEREC software v. 4.4 using the Biogeneric Copy op- tion; Dentsply Sirona) (Fig. 9). The restorations were milled from blocks of a zirconia-reinforced lith- ium silicate (Celtra Duo; Dentsply Sirona Restorative) of A2 HT shade, finished with water-cooled diamond cutters and adapted on the model (Figs. 10 and 11). Having ensured that the restorations were clean and free of grease and residue, they were customized with stains and glaze and subsequently fired. A more intensive shade effect (Fig. 12) was achieved by repeating cycles of applying and firing the ma- terial. The first stain/glaze firing took place at 820°C and the second one at a lower 770°C. The restorations were tried in with the aid of a glycerine-based gel (Try- In; Ivoclar Vivadent, Schaan, Liech- tenstein). Care was taken to ensure a good marginal fit, correct proximal contacts, a harmonious contour of the incisal edges and an appropriate shade. Minor corrections were car- ried out with a diamond cutter un- der irrigation, followed by polishing. After the try-in, the teeth were isolat- ed with rubber dam and cleaned. The ceramic restorations were etched on the adhesive surface using hy- drofluoric acid (Ultradent Porcelain Etch; Ultradent, South Jordan, Utah, USA) for 30 seconds and conditioned with a silane solution (Calibra, Dent- sply Sirona Restorative) for 60 sec- onds. The teeth were conditioned with 36% phosphoric acid (DeTrey Conditioner 36; Dentsply Sirona Restorative) for 30 seconds on the enamel and 15 seconds on the den- tin and subsequently with Prime & Bond® XP + Self-Cure Activator (Dentsply Sirona Restorative). Calibra dual-curing resin cement (Dentsply Sirona Restorative) was used for adhesively cementing the full and partial crowns. The veneers were used with a light-curing ce- ment (Calibra Esthetic Resin Cement, Dentsply Sirona Restorative). After thorough removal of any excess res- in and light curing, the occlusion was checked and the restorations were polished (Figs. 13 and 14). The zirconia-reinforced lithium sili- cate ceramics are characterized by good polishability and shade adap- tation to neighbouring structures (Figs. 15 and 16). Summary ZLS ceramics already have a high strength after milling2 and can be cemented adhesively immediately after polishing. In the present case, however, we decided to work with the laboratory to provide the res- torations, since many restorations have to be made at the same time and since the aesthetic result and the mechanical strength of the ce- ramic could be further improved by additional stain and glaze firing. The digital design of several restorations was considerably facilitated by the laboratory-made wax-up. By adapt- ing the restorations on the model, the patient’s chair time could be reduced. Adhesive cementing with Calibra was a very pleasant process, since any composite residue was easy to remove and the optical prop- erties of the ZLS ceramic were not ad- versely affected. Very good aesthetic results can be achieved with ZLS even for monolithic ceramic restorations. ZLS ceramics have improved me- chanical properties compared to lithium disilicate ceramics3. Howev- er, only a few case reports on clinical use have become available so far2, 4. Clinical trials are still pending. References 1. Frankenberger R, Mörig G, Blunck U, Hajtó J, Pröbster L, Ahlers MO. Prä- parationsregeln für Keramikinlays und –teilkronen unter der Berück- sichtigung der CAD/CAM-Technol- ogie. J Cont Dent Educ. 2007; (6), 86–92. 2. Rinke S, Schäfer S, Schmidt A-K. Einsatzmöglichkeiten zirkonoxid- verstärkter Lithiumsilikat-Keramik- en. Quintessenz Zahntech. 2014; 40(5): 536-546. 3. Elsaka SE, Elnaghy AM. Mechani- cal properties of zirconia reinforced lithium silicate glass-ceramic. Dent Mater. 2016; 32(7): 908–14- 4. von der Osten P. Zirkonoxidver- stärktes Lithiumsilikat für die Seiten- zahnversorgung. Quintessenz Zahn- tech. 2014; 40(7): 900-904. About the authors Tim Hausdörfer. Dr. med. dent. (Department of Preventive Dentistry, Peri- odontology and Cariology, University of Göttingen, Germany) Joachim Riechel. M.D.T. (Center for Dentistry and Oral and Maxil- lofacial Surgery, University of Göttingen)