Esthetic use of VITA PM9 by Xavier Zahno, Dental Technician
The ceramic press technique insures efficient working procedures resulting in a high standard of aesthetics. The all-in-one press ceramic VITA PM 9 is particularly straightforward to process with the VITA VM 9 ADD-ON ceramics for individualization. This is also confirmed by the following case example using the VITA VACUMAT 6000 MP pressing unit.
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Situation prior to treatment A male patient who places great importance on looking his best presented in a practice with emphasis on aesthetic dentistry for the full rehabilitation of his upper jaw – with the exception of the second molars. The teeth were healthy, but showed abrasion and slight axial rotation. The treatment goal expressed by the patient was a brilliant white smile modeled on the American Hollywood ideal. |
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Preliminary steps First a waxup was fabricated on the model, and the shape and length of the intended dental restorations determined with the aid of an intraoral mockup in a personal advisory session. The mockup was corrected in accordance with the information supplied by the patient. On this basis a silicone key was then fabricated for the preparation work to be carried out by the dentist. The preparation was minimally invasive with a slight chamfer. According to the working instructions, VITA PM 9 is suitable for the manufacture of substructure-free inlay, onlay, veneer and anterior/posterior crown restorations as well as the overpressing of zirconium dioxide frameworks. In this particular case all crowns manufactured were substructure-free, and were in many areas below the recommended minimum wall thicknesses – for anterior crowns at least 1.5 mm incisally and 1.0 mm cervically. The dentist assumes that the restorations will have sufficient stability through the adhesive cementation. After preparation the definitive impression-taking was carried out and the patient received an indirect provisional which had been manufactured on the basis of the mockup fabricated in VITA VM CC, a filler-free cold-curing polymer. |
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The press technique A fully anatomical waxup was made in order to use the cut-back technique at a later stage. After sprueing, the restoration was invested with VITA PM 9 investment material, with which we have obtained very good results to date. The pellets are available in three degrees of translucency – O (=Opaque), T (=Translucent) and HT (= High Translucent), each available in ten different shade variations matched to the VITA 3D-Master shade system. The patient’s choice in this case was the translucent variation in the shade 1M1. Pressing was carried out in the new VITA VACUMAT 6000 MP. Top results are obtained with this combined pressing unit for all dental ceramic firings. What is also impressive is how simple the VITA vPad comfort is to operate. |
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Comparatively little reworking was required, since very homogeneous pressing results can be obtained with VITA PM 9 – even in the case of thin crown margins with a thickness of less than 0.5 mm. Flashings are virtually excluded. Furthermore, the homogeneous structure of the press ceramic is easy to process with diamond instruments – not too hard and not too soft. VITA PM 9 is also, unlike press ceramics of other manufacturers, not susceptible to fracture. No chipping is observed when processing with rubber polishers. | |
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Individualization In a further stage of the working procedure, a stains fixing firing was carried out. Suitable materials for this purpose are VITA AKZENT stains and – in my opinion – the more intense and lifelike VITA INTERNO stains, which were used here. The restorations were individualized with the low-melting VITA VM 9 ADD-ON ceramics (800° C), which are based on the fine-structure veneering ceramic VITA VM 9 and are available in a compact assortment comprising eight shades. The materials used for the crowns were ADD1 transparent shade and ADD2 light enamel shade. The working properties and stability characteristics are very good. |
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A glaze firing was subsequently carried out in order to seal, and to give an impression of depth to the pressed surfaces to which no ADD-ON materials were applied. The individualized surfaces should not be coated with glaze, as the surface will otherwise become inhomogeneous. Since the VITA VACUMAT 6000 MP is a combined pressing unit, the ceramic firings were able to be carried out with the same firing unit as the pressing procedure. | |
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Results After seating the crowns using the adhesive technique, the patient confirmed that the result corresponded exactly to his expectations. The more pronounced lip support, the more rounded contour of the crowns, and the shading are exactly what he wanted. |
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Experiences With VITA PM 9, highly aesthetic results can be achieved in a quick and simple procedure. With pellets in three differing degrees of translucency and the range of ADD-ON materials, the perfect solution can be found for each patient.
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An advantage is that the press ceramic is distinguished by such a degree of natural translucency (fig. 12) that hardly any layering is necessary in order to reproduce its natural counterpart. The staining technique is mostly sufficient in order to achieve highly aesthetic results. The characteristic features of natural teeth displayed by restorations made of VITA PM 9, for instance their material properties resembling those of natural tooth enamel, ensure their long-term success. I would like to thank Dr. Molos Tomic (LACLINIC, Montreux, Switzerland) for his excellent collaboration. | |
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About the Author:
Xavier Zahno trained as a dental technician in Bern, Switzerland and has worked with many prominent laboratories and dental practices, including Dr. Kenneth Malament in Boston (2001-2002), University of Zurich (Laboratory Manager, Dept. of Crown and Bridge Technology and Materials Sciences 2006-2010) and is currently a joint partner of the Labor Précisdents Sàrl in Fribourg, Switzerland. |
