Evaluation of platelet-rich plasma in combination with ...coimplante.odo.br/Biblioteca/Enxertos prp/Evaluation of platelet-rich... · Evaluation of platelet-rich plasma in combination

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.



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


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.



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


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



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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