Seite 8 - Quintessenz Zahntechnik

STEP BY STEP
TRANSLUCENT ZIRCONIA
156 Quintessenz Zahntech 2013;39(2):150–160
margin in order to ensure a precise marginal fit of the coping). The idea is to achieve a
better retentive surface for the bond with the temporary restoration, which was milled
from Ceramill Temp, during cementation, and also to produce better internal light scat-
ter due to an irregular porcelain surface. The anatomically reduced framework was then
milled from Ceramill Zolid and stained monochromatically using a dentin-coloured Ce-
ramill Liquid. The fully anatomical crown, which was fabricated using Ceramill Temp
(medium blank shade), can also be reduced using the CAD software if the plan is to ve-
neer or characterise the PMMA crown. The design of an anatomical tertiary framework
made from composite or high-quality PMMA resin on implant-supported restorations is
based on the following consideration (Fig 21): the risk of fracture is considerably higher
with implant-supported restorations than with restorations on natural prepared teeth
due to the absence of stimulus transfer. It therefore makes sense to incorporate the
overload component in the framework, so that important elements such as bone and
implant are protected. In this case, the resin veneer (made from PMMA or composite),
which has the least strength, functions on an overload component.
One of the advantages of this is the protection of the bone and the inserted implant.
Another positive aspect of this approach is also that, in the worst-case scenario, if the
veneer fractures as a result of overloading, easy, cost-effective replacement and repair of
the veneer are possible and it is also easier to access the screw channel.
For the left side of the model (teeth 24 to 27), the author had selected the following
indication: teeth 26 and 27 were to be splinted to compensate for the divergence of
the path of insertion and also to mask the “discoloured prepared tooth” and take into
account the aesthetic requirements. A conical Ceramill Zi primary unit was designed on
tooth 27 (Fig 22). Due to its increased opacity (Fig 23), conventional zirconia is ideal
for masking the unfavourable shade situation (e.g. discoloured tooth preparation, metal
cores, titanium abutments.
The cervical margins of the primary unit were polished to a high lustre using the Ce-
ramill zirconia polishers to create an ideal starting position for gingival adaptation. The
superstructure for teeth 26 and 27 (Fig 24) was then designed fully anatomically and
Bridge with precision
attachment
Fig 20 The opaque surface
modified with margin powder.
Fig 21 The Ceramill Sintron
abutment with the Ceramill
Zolid framework and – for
better illustration – the fully
anatomical Ceramill temporary
crown, which is not completely
seated.