Dental Tribune Asia Pacific Edition

Dental TribuneAsia Pacific Edition | 11/201518 Guide is held against the loaded in- vestment ring to check the correct sprueing (Fig. 5). The wax-up to be pressedshouldbepositionedwithin the marked area. The distance to the investment ring base must not be lessthan3mm(Fig.6). The investment materials (IPS PressVEST or IPS PressVEST Speed) are applied using a conventional method. Once mixed, a small quan- tity of investment material is brushed on to the occlusal surface and/or on to the screw channel of hybrid abutment crowns, and the insides of the crowns are filled with investmentmaterialusingasuitable instrumenttopreventairfrombeing trapped. After the IPS Silicone Ring has been placed on the investment ringbase,theinvestmentmaterialis slowly poured into the investment ringuptothemarkingonthesilicone ring. The IPS Investment Ring Gauge is positioned with a slightly hinged movement and then pressed into position. The investment material is allowed to set in a resting environ- ment (Figs. 7a–c). Once set, the in- vestment ring is preheated using a conventionalmethod. Pressing The IPS e.max Press Multi system includes the IPS e.max Press Multi One-Way Plunger, a single-use plunger, which is used in addition to theIPSe.maxAloxPlunger.Withthe appropriate programme having been selected on the press furnace, the cold IPS e.max Multi ingot is placed into the preheated invest- ment ring with the blank side facing downwards. Next, the cold One-Way Plunger and the Alox Plunger are positioned (Fig. 8). The loaded in- vestment ring is placed in the pre- heated press furnace and the press programme is started. As known from the conventional press tech- nique, the investment ring should be immediately removed from the furnace after the press process has ended and allowed to cool slowly. Divesting is performed in the fa- miliar way. The investment ring is separatedusingaseparatingdiscand carefully broken apart at the prede- termined breaking point (Fig. 9). Blastingwithpolishingbeadsat4bar (58 psi) pressure and then at 2 bar (29 psi) is recommended for remov- ing the investment material (Fig.10). The reaction layer is removed using IPS e.max Press Invex Liquid. The pressed object is immersed in Invex Liquid in a plastic cup, cleaned in an ultrasoniccleanerfor10–30minand then rinsed under running water. The white reaction layer can then be completely removed with alu- minium oxide (100 μm) at 1–2 bar (14.5–29 psi) pressure without leav- inganyresidue(Fig.11). Staining Finishingisperformedwithgrind- ing tools suitable for high-strength glass-ceramics. Work is carried out at low speed and light pressure. Overheating of the ceramic must be avoided. The restoration is tried in on the die (without a spacer) and the occlusion and articulation are TRENDS&APPLICATIONS Dr. Biju Krishnan ,UK AD Fig.8:With the blank side facing downwards,the cold Multi ingot is placed in the preheated investment ring.—Fig.9: Once pressed and cooled,the restoration is carefully divested.—Fig.10: Careful removal of the investment material with polishing beads. 8 9 10 DTAP1115_16-20_Spiegel 20.11.15 14:36 Seite 2 8910 DTAP1115_16-20_Spiegel 20.11.1514:36 Seite 2

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