Dentaltown August 2021 - 66

continuing
education
CBCT diagnostics
There is a solid industry consensus
regarding CBCT for implant and bone
augmentation procedures. Having a threedimensional
understanding of the anatomy
of interest and the surrounding anatomy is
critical to the planning process, and thus
3D imaging is almost always required.3
A cross-sectional image of the #12
edentulous area (Fig. 2a, p. 65) shows that
its thinnest area is less than 4 mm and the
midcrestal is only about 5 mm. Intraoral
photography (Fig. 2b, p. 65) shows a clear
buccal depression exactly where the implant
would have been placed.
One favorable aspect of single-site defects
with teeth present on either side is that the
contours mesial and distal to the defect
create a good anatomical spatial support
for the graft when placed.
Every surgeon must develop a strategy for
each bone-grafting procedure they perform.
In the world of implants, this requires taking
into consideration not just the current
state of the bone that's being addressed
but also the planned future restoration. By
the process of reverse-engineering, we can
more effectively plan the grafting techniques
needed to achieve the desired bone and
soft-tissue volumes. With those volumes, the
implant can be placed in the ideal position,
allowing for a restoration that promotes
not just good aesthetics and function but
also the long-term biological well-being of
the periodontium. As Dr. David Garber
wrote in a 1995 Compendium article on
restorative-driven implantology, " Today,
the restoration should be indistinguishable
from adjacent natural teeth. " 4
This is as true
now as it was then.
Nowadays, we can do this much easier
digitally and not have to do a traditional
diagnostic wax-up on stone models. Figs. 3a
and 3b show the use of cone-beam viewing
software with advanced features for this
digital " wax-up. " The ideal implant placement
for the restoration occurs outside of the
confi nes of the existing bone. Measuring
this defi ciency will help dictate the grafting
technique and inform us as to how much bone
volume to aim for. In this case, a horizontal
augmentation of about 3 mm is needed.
Materials
I will not get into surgical instruments,
because they can vary from provider to
provider, but there are two materials I use
regularly that are worth describing.
Fig. 3a: CBCT image shows a digitally
superimposed implant in the defi cient site
to assess how much volume is needed.
Fig. 3b: Sagittal image of digital implant.
Particulate graft
When it comes to bone-grafting materials,
there are four main options. An autogeneic
graft is a patient's bone harvested from
one location and transplanted to another.
Allogeneic graft is donated bone tissue from
another member of the same species (such as
a human cadaver bone from organ and tissue
donors). Xenogeneic graft is harvested tissue
from a different species, often bovine or pig.
Alloplast is synthetic lab-made material that
can be used in the same manner.
Each graft has its inherent advantages
and disadvantages in terms of resorption
time, strength and growth factor potential.
There are subtypes categorized by biological
factors, such as cortical vs. cancellous bone
or the type of sterilization process. Clinicians
sometimes use a mix of different types to
take advantage of their multiple properties.
Barrier membranes
Varying types of materials offer cell
occlusivity. This means preventing soft-tissue
infiltration from the overlying gingiva
into the bone-grafting space. These must
be biocompatible, so as to not create a
foreign-body response, and have enough
mechanical strength to not tear over the
Fig. 3a
Fig. 3b
Fig. 4a: Platelet-rich fi brin
(PRF) tubes after spinning in
the centrifuge and creating
the platelet-rich plasma (PRP)
plugs at the top.
Fig. 4b: Tray holding
the resorbable collagen
membrane, the PRP plugs and
the hydrated allograft syringe.
Fig. 4a
Fig. 4b
66 AUGUST 2021 // dentaltown.com
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Dentaltown August 2021

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