Page 27 - DT Vol 15 No 3

aesthetics I
DENTAL TECHNOLOGY, JULY-SEPTEMBER 2025 27

CASE III: COMPLICATED CASE WITH DIFFERENT ABUTMENT COLOURS AND LITTLE AVAILABLE SPACE

Fig 15: Work order: four all-ceramic anterior crowns Fig 16a-b: Finished crowns (zirconium oxide base and microstratification) on the model. Monolithic palatal
for a young patient who comes to the laboratory restoration, finished with vestibular microstratification
for colour selection due to high esthetic demand.
Colour matching by Colour Index (Bleach shade
OM3, with seven-layer colour gradient layers,
ArgenZ HT+ Multilayer)

Fig 17: Impression of the restoration the day after cementation. The condition of Fig 18: Significant improvement in red-white aesthetics is visible already after one
the gingiva will improve significantly in the following weeks. month. The crowns are made of almost 90% zirconium oxide (ArgenZ HT+OM 3
Multilayer)

(displays, reflectors/bouncers, etc.), it is possible to obtain photographic
results of great accuracy and high added value. However, the procedure
requires considerable time and technique. As an alternative, good photos
can also be taken with the advanced cameras of modern smartphones. The
important thing is that a picture is taken. Work should always be performed
under a calibrated light source (e.g., Smile Lite, Figure 7). To create the
photo, a conventional colour key (Vita colour scale, Figure 8) and an
individual colour sample (colour index, Figure 9) are used. On this basis,
colour matching is carried out (Figure 10). If one takes into account the
volume of a premolar, a molar, and an anterior, the success rate is high.

PERFECT MATCH OR NONE AT ALL?
When colour matching is performed using the Colour-Index, it is possible
to select the base colour quickly, provided that the range of zirconia oxides
offers a sufficiently complete selection of shades. For example, ArgenZ HT+
Fig 19: Happy patient: the final in situ result Multilayer integrates 25 different shades, enabling dental technicians to
achieve the perfect match effortlessly. Zirconium oxides that are only offered
reference (Vita colour scale). The deviations of some multilayer zirconium in a limited assortment by colour groups often end up in the “no match”
oxides are sometimes significant. Problems include excessive translucency, a category. Dissonances make the work more difficult.
pronounced grey tone, unnatural colours, visible transitions, or incorrectly The idea of reducing the range of materials in the dental laboratory and
positioned colour layers. But there are also positive examples. We have had offering only a few multilayer ingots for “all cases” is ambitious and appealing,
good experiences with ArgenZ HT+ Multilayer, which enables good colour but unfortunately it does not work in daily life. Some manufacturers now
indexing (Figures 3 to 6). In this way, it is possible to accurately achieve “A3, recommend using a slightly lighter shade in the range—for example, instead
but a little lighter.” The result is an excellent base for microstratification. The of an A3, one should use an A2, with the restoration adapted by tinting. This
zirconium oxide base matches the desired base colour with a high degree of seems to be the wrong approach at a time when reproducibility is required.
certainty, making it possible to focus completely on the finish, aesthetics, and “If I need an A3, I use an A3,” is our position. ArgenZ HT+ Multilayer
individual characteristics of the restoration. integrates so-called L-Shades, which have a slightly higher brightness value
to accommodate additional finishes. This provides security and ensures
CHOOSING COLOURS ON THE PATIENT reproducible results.
If the patient is referred to the dental laboratory for colour selection, the
well-known guidelines are applied (neutral colour environment, absence of COMFORTABLE AND SAFE
clothing with strong colours, no lipstick, correct lighting conditions, etc.). Comfortable and safe is what a contemporary multilayer zirconium oxide
Incidentally, a black hairdressing cape has been shown to be effective in should inspire today (Figures 11 to 14). The respective zirconium oxide
neutralizing surrounding colours. We also use black lip and cheek protectors should allow for a predictable result without requiring constant consideration
to avoid reflections. of difficult-to-control factors during processing. Because, let’s be honest,
Photographic documentation is essential for determining colour in the only in a few cases do we truly have all the influencing factors under control
patient’s mouth. With a digital SLR camera and the appropriate equipment in the dental laboratory. We need materials that provide flexible application