Zirconia-Reinforced Lithium Disilicate: Pressing Ceramics Without Having to Compromise!

A 42-year-old female patient presented to a dental office to eliminate a problem that had been bothering her for years. After a traumatic fracture, teeth 11 and 12 had been restored with full crowns. Three times, the crowns had been made of lithium disilicate and minimally individualized with veneering ceramic. Three times, she had been unhappy with the result. The crowns appeared shapeless and lifeless, and were not acceptable for the patient who regularly interacts with customers in a professional context. The decision was made to use VITA AMBRIA to demonstrate its potential for esthetic cases. The tooth shade A2 was determined using the VITA classical A1–D4 shade guide. After that, a layering sketch was made, in order to have all the necessary effect details for lifelike reproduction in the laboratory. The old crowns were removed and the tooth stumps were briefly re-prepared under local anesthesia. An impression was taken and temporary restorations were fabricated.

After the master model was made and articulated with the opposing jaw model, a wax up was performed. The marginal areas were modeled with a sharp, thin finish and the shape was established in wax to match the ceramic result. No compromises were made. The minimum layer thicknesses of 1.2 millimeters in the cervical area and 0.8 millimeters in the incisal area for partially veneered full crowns was applied. Only the incisal area was anatomically reduced. Overcontouring in the marginal region was avoided in order to enable quick finishing later on. The crowns were sprued and invested in VITA AMBRIA INVEST. After curing the investment material and burning out the wax in the furnace, the ceramic restorations were pressed in the VITA VACUMAT 6000 MP press furnace with VITA AMBRIA A2 HT. Once the ceramic had cooled down, the plunger area was removed circularly with the separating disk. Rough divestment was then carried out at four bar pressure with an aluminum oxide grain size of 50 micrometers, and fine divestment at two bar pressure. The ceramic restorations proved to be very robust, even in the delicate marginal area, which turned out perfectly. A reaction layer to the investment material was not visible, which is why divesting worked quickly and reliably without having to accept any morphological or functional deficits. After separation of the sprue and its leveling, the precise individualization with the universal veneering ceramic VITA LUMEX AC (VITA Zahnfabrik, Bad Säckingen, Germany) followed.

Since the basic tooth shade had already been established using the true-to-shade VITA AMBRIA press ceramic with natural fluorescence, opalescence and translucency, the individualization of the veneering ceramic could be carried out quickly in extremely thin layers. The cervical area was given a more chromatic appearance using VITA LUMEX AC DENTINE MODIFIER in honey. Tooth 11 was then layered with DENTINE MODIFIER cloudy-white to give it a whitish touch. The dentine cores of both crowns were then layered with DENTINE A2 in the determined basic tooth shade. MAMELON saffron was applied selectively between the created mamelon structures to achieve a three-dimensional depth effect of the anatomical structure. Thanks to the stability of the material, accurate application was possible, even with limited space available, without losing the optical appearance of the different layers. The enamel layering of tooth 12 started in the lower third with TRANSLUCENT smoky-white to integrate a whitish effect in this area as well. In the upper third, both crowns were overlaid with TRANSLUCENT foggy-grey. In the area of the incisal edge and on the edges, a bluish accentuation with TRANSLUCENT deep-blue followed. After the firing, the restorations were first finished with the Diagen-Turbo-Grinder diamond grinder (bredent group, Senden, Germany) to match the patient’s age. A rubber polisher then enabled surface smoothness and texture. The right level of gloss was achieved with a goat hair brush and Fegupol Diabra diamond polishing paste (Feguramed GmbH, Buchen, Germany).

On the model, the two finished crowns already looked lifelike and natural. The try-in was supposed to show whether the crowns met the expectations of the patient who had been disappointed with the previous results. After local anesthesia, the temporaries were removed, the dies cleaned and the anterior crowns tried in. The crowns impressed with their precise fit. Taking a critical look in the hand mirror, the patient checked the esthetic appearance. After a brief moment, the tension in the treatment room dissolved. The patient smiled happily and the crowns could be definitively placed after luminal hydrofluoric acid etching and silanization with a self-adhesive luting composite. The ceramic core made of pressed VITA AMBRIA had enabled a lifelike reproduction of the natural incisors in the second quadrant with only minimal individualizations of the veneering ceramic. With the usual press ceramic procedure, a perfect fit and esthetics were achieved, thanks to a new material formula. VITA AMBRIA is a press ceramic that does exactly what it was made for and will make dental technicians enjoy working.