Dentaltown August 2021 - 67

Fig. 5a
Fig. 5b
Fig. 5a: A CBCT coronal image shows
the contour peaks of the teeth
neighboring the edentulous area.
Fig. 5b: An intraoral image of the
gingival fl ap shows the contours
of the neighboring teeth.
Fig. 6
Fig. 7
Fig. 6: An intraoral image shows the
decortication of the cortical bone to create
bleeding from the medullary bone.
Fig. 7: An intraoral image shows the
allograft placed in the defect, and the
resorbable collagen membrane tucked
between it and the gingival fl ap.
Fig. 8a
Fig. 8b
Fig. 8a: Platelet-rich fi brin membrane
laid over the resorbable collagen
membrane and over the crest to
cover the fl apped area.
Fig. 8b: Mattress and interrupted
sutures placed to secure the fl ap and
ensure limited mobility.
graft and maintain the desired space created
by the clinician. Some types degrade or
resorb with time and others do not. When
using resorbable membranes-usually made
of bovine or porcine collagen-one must
choose a material with a degradation time
that closely matches the rate of regeneration of
the grafted bone. Nonresorbable membranes
require a second surgery to remove them
after the bone has formed.
For most beginner- to intermediate-level
practitioners, the most common materials
used in this mild case (less than 4 mm of
defect) will be particulate allograft and
resorbable collagen membranes. These
materials will have resorbed by the end of
the four-month healing period.
(A good reference source for a more
in-depth explanation of each type of grafting
material is Bone Augmentation in Implant
Dentistry by Drs. Michael Pikos and Richard
Miron.5
)
Before surgery
On the day of surgery, I start by drawing
blood and spinning it down to create
a platelet-rich fibrin (PRF) membrane
(Fig. 4a). Compared with a natural clot, this
pliable membrane has almost 20 times the
concentration of platelets that release growth
factors over the fi rst 10 days after surgery.6
The viscous plasma collected at the
bottom of the PRF tray can hydrate both
bone graft particles (which makes them
easier to manipulate) and the resorbable
collagen membrane (Fig. 4b). The plasma is
also rich in platelets and subsequent growth
factors; a high concentration of fi brin serves
as a matrix to keep the growth factors in the
surgical site longer so the can enact their
positive effect.
Doing this in the beginning saves time;
the tubes can be spun-settings vary depending
upon the brand of centrifuge and desired
type of membrane-and sit in stable form
while you perform your surgery.
These protocols should not be thought of
solely in terms of " spin speed. " The speed is
the setting, but depending on the centrifuge
design (radius of the rotor and angle of
the tube slots), the speed correlates to a
centrifugal force (or " G " ) that is produced.
The G-force on the blood in the tubes
separates red blood cells from the plasma
that will include platelets, leukocytes and
fi brin.6
In the early 2000s, higher speed
protocols produced G-forces of 700-800 G.
Newer slow-spin recommendations allow
for a spectrum of different platelet products.
Choukroun's low-spin protocol of 700 rpm
creates only 60 G of force and allows us to
create what has been termed " injectable
PRF " -a nonclotted liquid plasma, rich
in platelets, that can be injected or used
to hydrate graft particles. Slightly higher
spins of 1,300 rpm create only 200-300 G
and can produce traditional platelet clots.
However, the reduced Gs allows for retention
of drastically more leukocytes in the platelet
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Dentaltown August 2021

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