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quarter 3 | 2013 | cerecdoctors.com | 13
how much tooth to remove to match the
model alterations thathavebeendone.The
secondmethod allows for easier seating of
the guide, but leads to more wasted time
waiting for the guide to mill. I opted for
the latter in this case.
Once profound anesthesia is achieved,
the tooth is removed as atraumatically
as possible with periotomes and forceps.
The site is thoroughlydebridedand rinsed
with saline. A collagen plug is then placed
in the socket to reduce bleeding during
the Galileos scan. It will subsequently be
removed once implant surgery begins.
The thermoplastic stent is placed and
complete seating is verified. The stability
of theguide is alsochecked tomake sure it
is stable and does not move. The Galileos
CBCT scan is then taken. Once the
data is reconstructed, the CAD/CAM
data is imported into the software
(Figs. 5) and the implant is then placed
with the software under the restorative
plan. The proper size and orientation
of the implant can then be determined.
The amount of bone support is also
able to be determined and taken into
account in relation to the position of the
implant and the restorative plan (Fig. 6).
In this case, it was determined there
was adequate space for a 4 mm x 11 mm
Conus 12 implant fromBlue Sky Bio. This
is an Astra clone with a more aggressive
thread profile that leads to better primary
stability in immediate placement cases.
After the implant is planned, the
length of the surgical drills is used to
determine the top of the guide. This is
the D2measurement. This number is the
length of the drill minus 1mm. This 1mm
accounts for the thickness of the keys
or sleeve that will be inserted into the
guide. This information is then exported
out of Galileos and imported into the
CEREC. The mill preview automatically
opens with the preview of the milled
guide, which is then milled (Fig. 7).
This guide is then inserted into the
thermoplastic stent.
The underside of the thermoplastic
must be removed to access the predrilled
hole in the guide. The best method I have
found is to use a tissue punch on a very
low RPM, and then core out a circle just
larger than the predrilled hole (Fig. 8).
The stent with the milled guide is then
placed in the patient’s mouth, and the
key is placed in the guide. This case was
done using the Astra keys for CEREC
Guide and the Astra single-use surgical
drills, since they match the diameters of
the Conus implants. The various diam-
eter drills are then sequenced through
to depth through the guide (Fig. 9). Once
the osteotomy is created, the implant is
placed in the site and primary stability
of 35ncm is obtained (Fig. 10). The
final placement was designed to be just
Fig. 1: Pre-op radiograph
Fig. 2: Working model
Fig. 3: Modified model
Fig. 4: Thermal plastic material
and marker
Fig. 5: Imported CAD/CAM data
Fig. 6: Bone support determined
Fig. 7: Mill Preview
Fig. 8: Thermal plastic material
removed
Fig. 9: Guided drill
Fig. 10: Implant placed
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