CATEGORY 58 AUSTRALASIAN DENTIST A 71-year-old patient presented with an extensive restoration on tooth 46 and secondary caries. Due to the insufficient restoration, treatment with a full crown was indicated. Ivoclar’s new zirconia material IPS e.max ZirCAD Prime was selected for the present case, as it allows the chairside fabrication of restorations and thus offers an innovative alternative to conventional procedures. The aim was to provide the patient with a full contour zirconia crown in a single visit lasting about 90 minutes. Clinical procedure “Due to the recurrent cusp fracture and the presence of an extensive restoration (Fig. 1), I decided to first restore tooth 46 with a in the Programat CS6 (Ivoclar) in just 15 minutes. This was followed by the polishing of the occlusal contact points and the application of the glazing material IPS e.max CAD Crystall./ Glaze Paste/ FLUO (Ivoclar) and glaze firing in the Programat CS6. Alternatively, due to the multi-layered structure of the block and the resulting natural shade and translucency gradient, the crown can be polished to a high gloss before and after sintering using the polishing set Ivoclar specifically developed for this purpose, thereby eliminating the need for glaze firing. In the present case, glaze firing was selected because sufficient time was available. In a subsequent step, the inner surfaces of the crown were blasted using 50 µm alumina at a pressure of 1.5 bar. After try-in and verification of the preparation margins, proximal contacts and occlusion, the crown was cleaned with Ivoclean and adhesively cemented with Speedcem Plus (Ivoclar). Finally, any cement residue was removed, and the occlusion checked once again. Clinical result At the follow-up appointment one week after the placement, the final restoration was thoroughly evaluated. The patient was extremely satisfied with the harmonious, aesthetic integration of the restoration in the dental arch as well as with the natural shade effect. She found the restoration comfortable to wear and easy to chew with. (Figs 9, 10). Conclusion Dentists already using a chairside system will be able to prepare zirconia crowns with IPS e.max ZirCAD Prime (Ivoclar) for their patients in just one session. The material is characterised by high mechanical strength (flexural strength of up to 1,100 MPa) and enables toothpreserving preparation due to minimal wall thicknesses starting at 0.8mm. The different layers incorporated in the block create a natural aesthetic appearance as the crown shows a harmonious natural progression of shade and translucency. This ensures uncomplicated processing, reliable strength, and an aesthetically pleasing result in your dental practice. u Chairside fabrication of a Zirconia crown with IPS e.max® ZirCAD Prime in a single visit By Dr Michael Weyhrauch By Dr Michael Weyhrauch Figure 1: Initial intraoral image of region 46. Figure 2: Lower jaw scan restoration planning. Figure 4: Instruments used for finishing the CAD/CAM chairside restoration. Figure 9: Harmonious integration in the posterior region. Figure 8: Instruments for the cementation of a zirconia crown – prepared for clinical use on site. Figure 6: Speed sintering in Programat CS6. Figure 3: Detailed view of the scan of tooth 46 and preparation margins. Figure 5: Smoothing the connector area. Figure 10: Lateral view with open jaw. Figure 7: Glazing to achieve a natural aesthetic appearance. CLINICAL new core build-up and then prepare it for a single crown.” The treatment plan for tooth 46 involved the placement of a chairside-fabricated IPS e.max ZirCAD Prime crown. After the initial diagnostic scan and digital isolation of the preparation area, the tooth was excavated and reconstructed with a new core buildup using MultiCore (Ivoclar). In addition, Delite Premium MTA (Kaniedenta) was applied to cover the pulp-near dentine. The tooth preparation was carried out with a light chamfer finish line, followed by gingival retraction using the double-cord technique. After the removal of the retraction cords, a detailed scan of the prepared area was performed (Figs 2, 3). In the next step, the crown was designed using CEREC software (version 5.3.3) and milled with CEREC Primemill (Dentsply Sirona) in approximately 14 minutes. This was followed by finishing of the zirconia restoration (Figs 4 – 7). The connector was removed using a carbide bur from a CAD/ CAM chairside finishing instrument set and subsequently smoothed with a rubber polisher from the same system. The crown was then speed-sintered
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