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ePaper created 2017-12-14, 09:23:12 | version 1.38.0
14 TRENDS & APPLICATIONS Dental Tribune Asia Pacific Edition | 12/2017 6 9 7 8 10 11 Fig. 6: Enamel etching prior to application of the adhesive.—Fig. 7: Applying Variolink Esthetic DC into the crown.—Fig. 8: Placing the crown.—Fig. 9: Excess removal is easily achieved owing to the new technology based on the Ivocerin photoinitiator.—Fig. 10: Final curing. Excess luting material was removed beforehand (quarter technique).—Fig. 11: Seated crown after excess removal.—Figs. 12a & b: Lateral and occlusal views of the completed restoration. “Almost any colour can theoretically be reproduced with ceramics by exploiting their natural translucent properties.” tage, since amine may be impli- cated in discoloration of the ce- ment line over time. One material, five shades Variolink Esthetic (Ivoclar Vivadent) is based on the value shade concept. The shades are classified according to the effect to be achieved with the cement. Five shades are available: Light+, Light, Neutral, Warm and Warm+. In this way, the shade spectrum ranges from an opaque white tone (Light+) to an opaque yel- low-brownish shade (Warm+). In between lie shades such as a co- conut water white and a neutral tone (very translucent) and a warm tone (comparable to A3). In addition, the luting composite is available in an LC (light-curing) and a DC (dual-curing) version. The LC version is designed for rel- atively thin restorations, such as inlays, onlays and veneers. The DC version is suitable for more extensive and opaque restora- tions. The luting composite is used in conjunction with the light-curing single-component Tetric N-Bond Universal (Ivoclar Vivadent). Clinical case A 45-year-old male patient presented to the practice with a restoration on tooth #46. The tooth had been endodontically treated and temporised with a fill- ing (Fig. 1). The temporary was re- moved, the tooth built up with Tetric N-Ceram Bulk Fill (Ivoclar Vivadent) and then prepared for the crown restoration (Fig. 2). An impression was taken with a one- step, two-phase impression tech- nique using a putty and light- body silicone. After scanning the model, the crown was designed in one second of light curing, the sur- face is set and excess can be bro- ken off, but the material is still paste-like at the interface to the crown or tooth. Excess can be polymerised en bloc and pulled off as a ring in one go with no uncured material left in contact with the tooth or crown. In addition, the luting composite does not contain amine, which is another advan- and retention. However, the re- tention is significantly reduced with partial crowns, veneers or onlays. It is therefore advisable to use a luting material that is capa- ble of providing a strong adhesive bond. Both problems led to the widespread use of luting compos- ite materials. Perhaps their only disadvantage is the removal of excess material. These luting ma- terials are hard and solid and not water soluble, and they have a high adhesive strength, making removal of excess difficult. Early luting composites were equipped with a self-cure mechanism. Users had to wait a few minutes until the composite was almost fully set before they could re- move the excess material. This period was risky because of the moisture in the mouth. Blood or saliva could come into contact with the non-polymerised com- posite and cause damage. Dual-curing luting composites These issues led to the rise of dual-curing composites for the ce- mentation of all-ceramic crowns. Dual-curing luting composites are usually delivered in double-push syringes with a mixing tip. During extrusion, the base and catalyst are automatically mixed. The ma- terial can be applied directly. The main advantage is that the curing process can be accelerated with light and excess material can eas- ily be removed. At the same time, the self-cure mechanism ensures a reliable cure, even with rela- tively thick or opaque ceramic lay- ers. Nonetheless, there are some situations in which excess mate- rial cannot be removed all that easily because the setting reaction takes place too quickly or the ma- terial does not cure down to the depth of the composite layer. After “[…] the self-cure mechanism ensures a reliable cure, even with relatively thick or opaque ceramic layers.” 12a 12b