Evaluation of platelet-rich plasma incombination with freeze-dried bonein the rabbit craniumA pilot study
Tara L. AghalooPeter K. MoyEarl G. Freymiller
Authors’ affiliations:Tara L. Aghaloo, Earl G. Freymiller, Oral andMaxillofacial Surgery, School of Dentistry, UCLA,Los Angeles, CA, USAPeter K. Moy, Oral and Maxillofacial Surgery,School of Dentistry, UCLA, Brentwood, CA, USA
Correspondence to:Tara L. AghalooOral and Maxillofacial SurgeryUCLASchool of Dentistry10833 Le Conte Ave. Rm. 53-076Los Angeles, CAUSATel.: þ1-(310)-794-7070Fax: þ1-(310)-794-2198e-mail: [email protected]
Key words: animal study, bone grafting, cranial defects, freeze-dried demineralized bone,
freeze-dried mineralized bone, histomorphometry, platelet-rich plasma
Abstract: Platelet-rich plasma (PRP) offers a new and potentially useful adjunct to allograft
materials in oral and maxillofacial bone and implant reconstructive surgery. This study
compares bone healing in four cranial defects in the rabbit grafted with freeze-dried
mineralized bone (FMB) alone, FMBþPRP, freeze-dried demineralized bone (FDDB) alone,
and FDDBþPRP. Fifteen New Zealand white rabbits were included in this randomized,
blind, prospective pilot study. Four equal 8mm diameter defects were created in each rabbit
cranium and immediately grafted with the above materials. Five rabbits were evaluated at
1, 2, and 4 months. Radiographically, FMBþPRP showed a tendency toward increased bone
density over FMB alone, but was not statistically significant (P40.05), and FDDBþPRP
showed a tendency toward increased bone density over FDDB alone, but was not
statistically significant (P40.05). Histomorphometrically, FMBþPRP showed a tendency
toward increased bone area over FMB alone at 1 and 4 months, but was not statistically
significant (P40.05), and FDDBþPRP showed a tendency toward increased bone area over
FDDB alone, at 1 and 2 months, but was not statistically significant (P40.05). This study
failed to show a radiographic or histomorphometric increase in bone formation with the
addition of PRP to either FMB or FDDB in non-critical-sized defects in the rabbit cranium.
Freeze-dried bone is a well-documented
bone-grafting material, utilized for oral
bone grafting in periodontal bony defects,
extraction sockets, maxillary sinus grafts,
and around dental implants (Hurt 1968;
Lane et al. 1972; Mellonig et al. 1976;
Sanders et al. 1983; Mellonig & Triplett
1993; Rominger & Triplett 1994; Valentini
& Abensur 1997; Groeneveld et al. 1999a,
1999b; Tal 1999; van den Bergh et al. 2000;
Haas et al. 2001; Karabuda et al. 2001). It
has also been successfully used to regener-
ate bone in rabbit critical-sized skull de-
fects (Shermak et al. 2000; Clokie et al.
2002). Freeze-dried bone is isolated from
cadavers, sterilized, lyophilized, or freeze-
dried, and stored in tissue banks (Burchardt
et al. 1978; Mellonig 1999). Freeze-dried
bone can be mineralized or demineralized.
The demineralization process, in removing
the mineral phase, exposes the collagen and
growth factors, including bone morphogen-
etic proteins (BMPs) (Mellonig 1999), and
may activate them (Schwartz et al. 1996).
Freeze-dried bone, especially the deminer-
alized type, may stimulate bone formation
through osteoinduction (Urist 1965; Yeo-
mans & Urist 1967; Urist et al. 1968; Urist
& Dowel 1970; Reddi & Huggins 1972) or
osteoconduction (Piatelli et al. 1996; Groe-
neveld et al. 1999). However, human clin-
ical trials fail to show osteoinductive
properties (Pinholt et al. 1992, 1994; Bec-
ker et al. 1994, 1996; Paul et al. 2001), andCopyright r Blackwell Munksgaard 2004
Date:Accepted 19 January 2004
To cite this article:Aghaloo TL, Moy PK, Freymiller EG. Evaluation ofplatelet-rich plasma in combination with freeze-driedbone in the rabbit cranium. A pilot study.Clin. Oral Impl. Res. 16, 2005; 250–257doi: 10.1111/j.1600-0501.2004.01075.x
250
osteoconductive properties are also ques-
tioned (Pinholt et al. 1992; Schwartz et al.
1996; Block & Kent 1997). Some early
studies show fibrous connective tissue sur-
rounding freeze-dried demineralized bone
(FDDB) particles and no new bone forma-
tion (Wetzel et al. 1995), and other studies
show incorporation of FDDB particles
with new bone and healthy osteocytes
(Brugnami et al. 1996). FDDB has even
been compared to autogenous bone and
was found to be similar in union of graft
and host bone, mechanical strength, poros-
ity, and new bone formation (Burchardt
et al. 1978; Quintero et al. 1982; Mellonig
1984; Haas et al. 2001). When freeze-dried
bone was compared to other non-autoge-
nous grafting materials, such as hydroxyla-
patite and deproteinized bovine bone
granules, it resorbed faster in sinus grafts
and was able to successfully support func-
tioning implants (Karabuda et al. 2001).
Other studies show that FDDB is compar-
able to deproteinized bovine bone material
in preserving alveolar ridge height after
extractions, and may be able to support
underlying tissue vascularization (Tal
1999). And still other studies show promis-
ing results for FDDB for periodontal ther-
apy (Sepe et al. 1978; Mellonig 1984; Gher
et al. 1994).
Comparisons of freeze-dried mineralized
bone (FMB) and FDDB exist, and again,
varied results have been shown. Since FMB
is mineralized, it may calcify faster than
FDDB. Sinus lifts where FMB was utilized
resulted in harder bony substance when
compared to FDDB, which resulted in
cartilage formation after 6 months (Meffert
1998). FMB has been well studied in adult
periodontitis, showing 50% bone fill in
more patients when it was added to auto-
genous bone, especially in furcation defects
(Mellonig 1991). FMB also regenerated new
bone, cementum, and periodontal ligament
in adult male baboons when compared to
control (Mellonig 1994). FMB may be more
effective for fenestrations, minor ridge aug-
mentation (Piatelli et al. 1996), fresh extrac-
tion sockets, and sinus lifts (Meffert 1998),
but FDDB is more widely used (Mellonig
1999). However, more studies exist with
the use of FDDB as a grafting material both
alone and in combination with autogenous
bone (Boeck-Neto et al. 2002).
The use of platelet-rich plasma (PRP)
offers a potentially useful adjunct to auto-
genous, allograft, and xenograft materials
in oral and maxillofacial bone and implant
reconstructive surgery. Some authors sug-
gest that the addition of PRP to osteocon-
ductive grafting materials can potentiate
osteoinduction (Kim et al. 2002a, 2002b).
Platelets are very important in the wound-
healing process. They arrive quickly to the
wound site and begin the coagulation pro-
cess. They release multiple wound-healing
growth factors and cytokines, including
platelet-derived growth factor (PDGF),
transforming growth factors beta 1 and 2
(TGF-b1 and TGF-b2), vascular endothelial
growth factor (VEGF), platelet-derived en-
dothelial cell growth factor (PDEGF), inter-
leukin-1 (IL-1), basic fibroblast growth
factor (bFGF), and platelet activating fac-
tor-4 (PAF-4) (Linder et al. 1979; Jones
et al. 1992; Harrison & Cramer 1993;
Miyadera et al. 1995; Mohle et al. 1997).
These growth factors are thought to con-
tribute to bone regeneration and increased
vascularity, vital features of a healing bone
graft. Questions exist whether PRP can be
utilized with alloplasts, xenografts, or allo-
graft materials without the incorporation of
autogenous donor bone to create a bone
graft, which is comparable or superior to
autogenous bone.
There are very few studies where PRP
was added to allograft or alloplast bone
(Kassolis et al. 2000; Kim et al. 2001,
2002a, 2002b; Shanaman et al. 2001;
Froum et al. 2002; Rodriguez et al. 2003;
Wiltfang et al. 2003; Wojtowicz et al.
2003). In many of these studies, few cases
were evaluated and limited statistical test-
ing was performed to confirm the validity
of the results. Specifically with allografts,
few scientific conclusions were reached.
Since both FMB and FDDB show such
varied results in previous studies, this
study aimed to determine whether FMB
or FDDB either alone or in combination
with PRP would result in bone regenera-
tion in rabbit cranial defects. Further sci-
entific testing of PRP in combination with
allograft materials such as FDDB and FMB
is obviously necessary. The present study
was designed to test the effectiveness of
PRP when added to an allograft.
Material and methods
Animal surgical procedure
Fifteen New Zealand white male rabbits
between 2.8 and 4 kg were included in this
randomized, blind, prospective pilot study.
The UCLA Animal Research Committee
in accordance with staff in the UCLA
Department of Laboratory and Animal
Medicine approved all animal protocols.
Each rabbit was anesthetized with keta-
mine (10 mg/kg) and acepromazine (1–
1.5 mg/kg), and given preoperative antibio-
tics (enrofloxacin 5 mg/kg, Bayer, Shaw-
nee Mission, KS, USA). Ten milliliters of
autologous blood was drawn from each
rabbit to prepare the PRP. The rabbits
underwent general anesthesia with 1–2%
isoflurane with standard monitoring. The
fur was shaved over the cranium and
prepped and draped in a sterile fashion.
An incision was made to the bony cranium
and the periosteum was reflected. Four
8 mm diameter defects were created with
a trephine bur with copious irrigation (Fig.
1). The four defects were randomly grafted
with FMB (LifeNet Transplant Services,
Virginia Beach, VA, USA) alone, FMB
mixed with PRP, FDDB (LifeNet Trans-
plant Services) alone, and FDDB mixed
with PRP. The wound was closed with
3-0 Dexon (Owens and Miner, Irvine,
CA, USA), first closing the dura mater to
contain the grafting materials and prevent
overflow of the different grafting materials,
and 3-0 Dexon in a subcuticular fashion.Fig. 1. Surgical sites prepared with 8 mm trephine
burr.
Aghaloo et al . Evaluation of PRP in combination with freeze-dried bone
251 | Clin. Oral Impl. Res. 16, 2005 / 250–257
The rabbits recovered from anesthesia
without complications. They were given
postoperative narcotic pain medication and
antibiotics.
PRP preparation
The 10 ml of autologous blood drawn from
each rabbit was combined with 1.1 cm3 of
anticoagulant citrate dextrose phosphate
(ACD-A) to prevent coagulation. The blood
was centrifuged at 1500 rpm (215g) for
10 min to separate the plasma containing
the platelets from the red cells (Sorvall,
Irvine, CA, USA). The plasma was drawn
off the top, mixed with 0.4 cm3 of ACD-A
anticoagulant, and centrifuged for an addi-
tional 10 min at 3000 rpm (863g) to sepa-
rate the platelets. The platelet-poor plasma
(PPP) was separated from the PRP along
with the buffy coat. The buffy coat and
PRP, approximately 1–1.5 cm3, were resus-
pended and used within minutes to add
to the grafting materials. Topical bovine
thrombin powder 5000 U (Jones, St Louis,
MO, USA) were reconstituted with 5 cm3
of 10% calcium chloride (American Re-
gent Laboratories, Shirley, NY, USA). The
ratio of PRP to calcium chloride activator
was 10 : 1. This protocol is similar to those
utilized in clinical practice with some of
the commercially available machines and
the original scientific article (Marx et al.
1998).
Platelet counts were performed on each
sample, including a peripheral blood count,
PPP count, and PRP count. A Unopette
microcollection system (Becton Dickin-
son, Franklin Lanes, NJ, USA) was used
to lyse the leukocytes and erythrocytes as
well as provide a standard dilution of 1 : 100
for platelet counts. The platelets were hand
counted with a standard hemocytometer,
and the total was calculated for each
sample.
Sample evaluation
Rabbits were sacrificed with Pentobarbital
(Western Medical Supply Inc., Arcadia,
CA, USA) 100 mg/kg IV at time periods
1, 2, and 4 months. There were five rabbits
in each group. The entire cranium was
removed with a reciprocating saw, without
encroaching upon the grafted areas.
Radiographs were taken of the rabbit
cranium in its entirety before histologic
sections were performed. A calcium carbo-
nate step wedge was used in each radio-
graph for comparison. Quantification was
performed with digital subtraction radio-
graphy. Specific computer software (UCLA
Image, UCLA, Los Angeles, CA, USA)
compared the pixels and grams per square
inch of all four grafting materials for each
rabbit (Fig. 2).
Specimens were treated with hydro-
chloric acid decalcifying solution (Fisher Sci-
entific, Tustin, CA, USA) and sectioned by
bisecting the 8 mm diameter defects. Speci-
mens were then dehydrated with grated
alcohols and embedded in paraffin. They
were subsequently sectioned at 6 mm with
a steel knife. The histologic specimens
were prepared in the usual fashion with
hematoxylin and eosin staining at 6mm in
thickness. Histologic evaluation was per-
formed at 10, 25, and � 40 magnification.
The � 40 magnification was used for histo-
morphometric analysis. The bone area was
calculated using ImagePro software (Image
Pro, Media Cybernetics, Silver Springs,
MD, USA). Evaluators were blind as to
the grafting material and time period for
each sample. The data were analyzed by a
Student’s t-test with a significance level at
Po0.05.
Results
Platelet counts performed confirmed that
the PRP preparation technique used in this
study produced a source of highly concen-
trated platelets (Fig. 3). The average per-
ipheral blood platelet count was 112,333/
mm3 with a range from 90,000 to 135,000/
mm3. The average platelet count in PPP
was 15,667/mm3 with a range from 8000
to 25,000/mm3. The average platelet count
in PRP was 1,137,667/mm3 with a range
from 800,000 to 1,465,000/mm3.
Radiographic evaluation
Figure 4 demonstrates the bone density as
determined radiographically. Digital sub-
traction radiography with step-wedge cali-
bration showed that all grafting materials
increased in bone density over the study
Fig. 2. Digitized radiograph of rabbit cranium 1 (a), 2 (b), and 4 months (c) after bone-grafting procedure. At 1
month, very radiolucent defect areas are seen. By 2 months, minimal ingrowth of bone from the defect margin
is seen, as well as the radiopacity of the grafting materials. By 4 months, the defects are increasingly radiodense,
but minimal difference can be seen between grafting materials. FDDB, freeze-dried demineralized bone; FMB,
freeze-dried mineralized bone; PRP, platelet-rich plasma.
0
800,000
600,000
400,000
200,000
1,000,000
1,200,000
Blood PPP PRP
Platelets
Fig. 3. Average platelet counts for peripheral blood,
platelet-poor plasma (PPP), and platelet-rich plasma
(PRP).
00.20.40.60.8
11.21.41.6
4
Months
Gra
ms/
sq in
chFMB FMB+PRPFDDB FDDB+PRP
3210
Fig. 4. Amount of bone fill determined radiographi-
cally over the 4-month study. FDDB, freeze-dried
demineralized bone; FMB, freeze-dried mineralized
bone; PRP, platelet-rich plasma.
Aghaloo et al . Evaluation of PRP in combination with freeze-dried bone
252 | Clin. Oral Impl. Res. 16, 2005 / 250–257
period (1–4 months). FDDBþPRP showed
a radiographic tendency toward increased
bone density over FDDB alone at 1 and 2
months, but was not statistically signific-
ant (P40.05). FMBþPRP also showed a
radiographic tendency toward increased
bone density over FMB alone at 1 and 2
months, but was not statistically signific-
ant (P40.05).
Histologic evaluation
Figure 5 shows the histologic evaluation of
all grafting materials at 1, 2, and 4 months
at � 40 magnification. The FMB sites at 1
month show extensive fibrous tissue with
FMB particles, which undergoes remodel-
ing at 1 and 2 months, with moderate bony
ingrowth by 4 months. FMBþPRP shows
a similar picture, with slightly more woven
bone formation throughout the study
period. The FDDB sites also show fibrous
connective tissue surrounded by FDDB
particles, which decrease over time and
are replaced by woven bone. When PRP is
added, bone formation is slightly increased.
In all groups, most of the bony ingrowth is
from the edges of native bone and from the
minimal osteoconductive activity that oc-
curs throughout the 4-month study period.
By 4 months, many of the freeze-dried
bone particles exist, and minimal bone
formation is taking place by osteoconduc-
tion by this time. There was no difference
in the method of bony ingrowth between
the grafting materials, whether PRP was
added or not.
Histomorphometric evaluation
Figure 6 shows the histomorphometric
percent bone area as a function of time for
each grafting material. When histologic
sections were evaluated with histomorpho-
metry, all grafting materials showed an
increase in bone area over the study period
(1–4 months). FDDBþPRP showed a
tendency toward increased bone area
over FDDB at 1 and 2 months, but this
was not statistically significant (P40.05).
FMBþ PRP showed a tendency toward
increased bone area over FMB at 1 and 4
months, but was not statistically signifi-
cant (P40.05).
Discussion
In implant dentistry, surgeons strive to
improve upon current bone-grafting tech-
niques and provide a faster and denser bony
regenerate. In addition, alternative grafting
materials are continuously studied to avoid
autogenous donor site morbidity (Kalk
et al. 1996). Often extensive grafting ma-
terial is required and only iliac crest bone
gives adequate volume. This donor site has
many potential complications including
chronic pain, sensory loss, hematoma, ser-
oma, wound breakdown, contour defect,
hernia through the donor site, gait disturb-
ance, instability of the sacroiliac joints,
pathologic fracture, adynamic ileus, and
ureteral injury (Kalk et al. 1996). An ideal
bone-grafting material should be able to
produce bone by osteogenesis, osteoinduc-
tion, or osteoconduction, remodel the ini-
tial graft material to mature lamellar bone,
maintain bone volume in function over
time, have a low risk of infection, ease of
availability, low antigenicity, and high
Fig. 5. Histologic evaluation of all grafted materials at 1 and 4 months. Magnification � 40. (a) FMB 1 month
– extensive fibrous tissue is seen among freeze-dried bone particles; (b) FMB 2 months – minimal bony
ingrowth from defect margins and extensive fibrous tissue is seen; (c) FMB 4 months – increased bony ingrowth
from defect margins, which almost bridge the gap of the defect; (d) FMBþPRP 1 month – extensive fibrous
tissue interspersed around freeze-dried bone particles is seen; (e) FMBþPRP 2 months – minimal bone
ingrowth from the defect margin is seen; (f) FMBþPRP 4 months – increased amount of woven bone ingrowth
from defect margins, which almost bridge the defect; (g) FDDB 1 month – multiple freeze-dried bone particles
and fibrous tissue are seen; (h) FDDB 2 months – more organized fibrous tissue stroma is seen, with minimal
bony ingrowth from the defect margins; (i) FDDB 4 months – increased bony ingrowth is seen; (j) FDDBþPRP
1 month – extensive freeze-dried bone particles are seen; (k) FDDBþPRP 2 months – more organized fibrous
tissue stroma surrounding freeze-dried bone particles; (l) FDDBþPRP 4 months – increased bony ingrowth
from defect margin with minimal fibrous tissue, bone is almost bridging the defect. FMB, freeze-dried
mineralized bone; PRP, platelet-rich plasma; FDDB, freeze-dried demineralized bone.
0
0.1
0.2
0.3
0.4
43210
Months
% B
on
e A
rea
FMB FMB+PRPFDDB FDDB+PRP
Fig. 6. Histomorphometric evaluation of bone area
over the 4-month study period. FDDB, freeze-dried
demineralized bone; FMB, freeze-dried mineralized
bone; PRP, platelet-rich plasma.
Aghaloo et al . Evaluation of PRP in combination with freeze-dried bone
253 | Clin. Oral Impl. Res. 16, 2005 / 250–257
reliability (Block & Kent 1997). Freeze-dried
bone is an allograft material widely used in
localized ridge augmentation, periodontal
bony defects, and grafting of small defects
around implants, which may possess these
characteristics of an ideal graft material.
This material may possess osteoinductive,
or more likely, osteoconductive properties
(Pinholt et al. 1992; Groeneveld et al.
1999b). The most effective use for freeze-
dried bone thus far, has been in regenera-
tion of periodontal defects where 78% of
defects responded with greater than 50% or
complete bone repair (Mellonig 1984), and
potential for use in implant site develop-
ment has shown some promising results
(Haas et al. 2001). Other studies have
shown negative results for the use of
FDDB, including lack of bone formation
and results showing less bone regeneration
than control sites when non-resorbable
membranes are used (Becker et al. 1995).
Since studies regarding freeze-dried bone
are conflicting and it is difficult to con-
clude if it can predictably form bone as a
solo grafting material, perhaps adding a
mixture of growth factors can aid in in-
creasing the graft vascularity and ulti-
mately, its success. It has been shown
that growth factors are a plausible way to
improve and expedite bony wound healing,
and may support osteoinduction of osteo-
conductive materials (Kim et al. 2002a,
2002b).
Platelets contain angiogenic, mitogenic,
and vascular growth factors in their gran-
ules (Banks et al. 1998; Maloney et al.
1998). VEGF is a powerful angiogenic
growth factor, with an important role in
wound healing (Thomas 1996). TGF-b1
and TGF-b2 have been shown to inhibit
bone resorption, osteoclast formation, and
osteoclast activity, as well as trigger rapid
maturation of collagen in early wounds
(Bonewald & Mundy 1990; Steenfos
1994). PDGF increases the population of
wound-healing cells, and recruits other
angiogenic growth factors to the wound
site (Steenfos 1994). It is therefore a reason-
able hypothesis that increasing the concen-
tration of platelets in a bone defect may
lead to improved and faster healing. How-
ever, little evidence exists evaluating the
effect of these growth factors to improve
bone healing when added to osteoconduc-
tive materials (Kim et al. 2001, 2002a,
2002b).
Quantitative platelet counts verified that
PRP was used in this study, consisting of
800,000–1,465,000 platelets in the concen-
trate (Marx et al. 1998). Digital subtraction
radiography with step-wedge calibration
showed that all grafting materials increased
in bone density over the study period (1–4
months). FDDBþPRP showed a radio-
graphic tendency toward increased bone
density over FDDB alone at 1 and 2
months, but was not statistically signific-
ant (P40.05). FMBþPRP also showed a
radiographic tendency toward increased
bone density over FMB alone at 1 and 2
months, but was not statistically signifi-
cant (P40.05).
When histologic sections were evaluated
with histomorphometry, all grafting mate-
rials showed an increase in bone area over
the study period (1–4 months). FDDBþPRP showed a tendency toward increased
bone area over FDDB at 1 and 2 months,
but this was not statistically significant
(P40.05). FMBþPRP showed a tendency
toward increased bone area over FMB at 1
and 4 months, but was not statistically
significant (P40.05). These data are not
in agreement with Kim et al., who showed
a significant histomorphometric increase
in bone–implant contact in the dog iliac
crest when PRP was added to FDDB simul-
taneously with placement of implants
(Kim et al. 2002a). Preliminary human
case series’ have shown that FDDB in
combination with PRP forms numerous
areas of osteoid and bone without inflam-
matory infiltrate or soft-tissue epitheliali-
zation, and osseous trabeculae surround
connective tissue (Kassolis et al. 2000;
Shanaman et al. 2001). However, in these
studies, no quantitative analysis was per-
formed and the grafted sites were not
standardized or randomized.
This study failed to show a significant
increase in bone formation with the addi-
tion of PRP to FMB or FDDB radiologically
or histomorphometrically in non-critical-
sized defects in the rabbit cranium.
The sample size was small, consisting of
only five rabbits at each time period, which
may have contributed to the results seen. A
true critical-sized cranial defect in the rab-
bit model is 15 mm (Vikjaer et al. 1997).
Therefore, four critical-sized defects cannot
be created in the rabbit cranium due to the
small size of the cranium. We chose a non-
critical-sized defect to evaluate the early
healing, and the potential ability of PRP to
improve this early healing when it was
added to freeze-dried bone-grafting materi-
als. Further studies are needed to evaluate
the potential benefits of PRP in combina-
tion with various autogenous, allograft, and
alloplast grafting materials.
Conclusion
This study evaluated grafting materials in
rabbit cranial defects, and did not show a
significant improvement with the addition
of PRP to FMB or FDDB at 1-, 2-, and 4-
month time periods.
Acknowledgements: The authors
would like to thank Dr Steven Paul for
excellent surgical assistance, and Wes
Hill and Jeff Kunkel for assistance with
histomorphometry.
Resume
Le plasma riche en plaquettes (PRP) offre un apport
nouveau et potentiellement utile aux allogreffes dans
la chirurgie reconstructrice implantaire et osseuse
buccale et maxillofaciale. Cette etude compare la
guerison osseuse dans quatre lesions craniennes chez
le lapin greffe avec de l’os mineralise congele sec
(FMB) seul, de l’os demineralise congele et sec
(FDDB) seul FMBþPRP, et FDDBþPRP. Quinze
lapins blancs de nouvelle-Zelande ont ete inclus
dans cette etude pilote prospective, aveugle et ran-
domisee. Quatre lesions d’un diametre de 8 mm ont
ete creees dans chaque crane des lapins et imme-
diatement greffees avec les materiaux mentionnes
ci-dessus. Cinq lapins ont ete evalues a un, deux et
quatre mois. Radiographiquement FMBþPRP mon-
trait une tendance d’accroıssement de la densite
osseuse plus importante que FMB, mais cette differ-
ence n’etait pas significative (P40,05); FDDB
þPRP accusait une tendance d’augmentation de la
densite osseuse plus importante que FDDB mais
egalement non-significative (P40,05). Histomor-
phometriquement, FMBþPRP montrait une ten-
dance (P40,05) a un accroıssement de l’aire
osseuse plus importante que FMB a un et quatre
mois; FDDBþ PRP montrait une tendance a un
accroıssement de l’aire osseuse plus importante que
FDDB mais a nouveau non-significative (P40,05).
Cette etude n’a donc pas demontre d’augmentation
radiographique ou histomorphometrique dans la for-
mation osseuse lorsque le PRP etait ajoute soit au
FMB soit au FDDB dans des lesions de grandeur non-
critique dans le crane du lapin.
Zusammenfassung
Die Evaluation von plattchenreichem Plasma in
Kombination mit gefriergetrocknetem Knochen
am Kaninchenschadel: Eine Pilotstudie
Aghaloo et al . Evaluation of PRP in combination with freeze-dried bone
254 | Clin. Oral Impl. Res. 16, 2005 / 250–257
Plattchenreiches Plasma (PRP) stellt einen neuen
und moglicherweise nutzlichen Zusatz zu Allo-
transplantatmaterialien in der oralen und maxillofa-
zialen rekonstruktiven Knochen- und Implantat-
chirurgie dar. Die Studie vergleicht die Knochenhei-
lung in vier Schadeldefekten beim Kaninchen,
welche mit gefriergetrocknetem mineralisiertem
Knochen (FMB) allein, gefriergetrocknetem miner-
alisiertem KnochenþPRP, gefriergetrocknetem
demineralisiertem Knochen (FDDB) allein und ge-
friergetrocknetem demineralisiertem KnochenþPRP aufgefullt worden waren. Funfzehn weisse
Neuseeland Kaninchen wurden in diese randomi-
sierte, blinde, prospektive Pilotstudie einbezogen.
Bei jedem Kaninchen wurden vier gleiche Defekte
mit einem Durchmesser von 8 mm in das Kranium
prapariert und sofort mit den oben aufgefuhrten
Materialien aufgefullt. Je funf Kaninchen wurden
nach einem, zwei bzw. vier Monaten untersucht.
Radiologisch zeigte FMBþPRP gegenuber FMB al-
lein eine Tendenz richtung zunehmender Knochen-
dichte, aber der Unterschied war statistisch nicht
signifikant (P40.05), und FDDBþPRP zeigte ge-
genuber FMB allein eine Tendenz richtung zuneh-
mender Knochendichte, aber der Unterschied war
statistisch nicht signifikant (P40.05). Histomor-
phometrisch zeigte FMBþPRP gegenuber FMB al-
lein eine Tendenz richtung grosseres Knochenareal
nach 1 und 4 Monaten, aber der Unterschied
war statistisch nicht signifikant (P40.05), und
FDDBþPRP zeigte eine Tendenz richtung grosseres
Knochenareal gegenuber FDDB allein, aber der
Unterschied war statistisch nicht signifikant.
(P40.05). In dieser Studie misslang es, eine radi-
ologische oder histomorphometrische Zunahme in
der Knochenbildung mittels Zusatz von PRP zu
entweder gefriergetrocknetem mineralisiertem oder
zu demineralisiertem Knochen bei nicht kritischen
Defekten im Kaninchenschadel zu zeigen.
Resumen
El plasma rico en plaquetas (PRP) ofrece un Nuevo y
potencialmente util accesorio para materiales de
aloinjerto en cirugıa reconstructiva oral y maxilofa-
cial de hueso e implantes. Este estudio compara la
cicatrizacion osea en cuatro defectos craneales en el
conejo injertado con hueso mineralizado crio-dese-
cado (FMB) solo, hueso crio-desecado mineraliza-
doþPRP, hueso crio-desecado desmineralizado
(FDDB) solo, y hueso crio-desecado desmineraliza-
doþPRP. Se incluyeron quince conejos blancos de
Nueva Zelanda en este estudio piloto aleatorio,
ciego, prospectivo. Se crearon cuatro defectos iguales
de 8 mm de diametro en el craneo de cada conejo y
se injertaron inmediatamente con los materiales
antes citados. Cinco conejos se evaluaron a uno,
dos y cuatro meses. Radiograficamente, FMBþPRP
mostro una tendencia hacia un area de hueso mayor
sobre FMB solo, pero no fue estadısticamente sig-
nificativa (P40.05), y FDDBþPRP mostro una
tendencia hacia una mayor densidad osea sobre
FDDB solo, pero no fue estadısticamente significa-
tiva (P40.05).
Histomorfometricamente, FMBþPRP mostraron
una tendencia hacia un area mayor de hueso sobre
FMB solo a 1 y 4 meses, pero no fue estadıstica-
mente significativa (P40.05), y FDDBþPRP mos-
traron una tendencia hacia una mayor area de hueso
sobre FDDB solo, pero no fue estadısticamente
significativa (P40.05). Este estudio fracaso en mos-
trar un incremento radiografico o histomorfometrico
en la formacion de hueso con la adicion de PRP a
hueso crio-secado tanto mineralizado como desmi-
neralizado en defectos de tamano no crıtico en el
craneo del conejo.
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