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Effect of platelet-rich plasma with autogenous bone graft for maxillary sinus augmentation in a rabbit model
Abstract
To evaluate the effect of platelet-rich plasma (PRP) on autogenous bone graft remodeling during sinus augmentation in a rabbit model.
Twelve New Zealand White rabbits were divided randomly into 3 groups based on their time of sacrifice (2, 4, and 8 weeks). All animals underwent a general anesthetic and harvesting of an autogenous bone graft from the right iliac crest with subsequent bilateral maxillary sinus augmentation. PRP was prepared via standard approved technique by acquiring 21 cc of autogenous blood and performing differential centrifugation to obtain PRP. One cc of PRP was produced that was mixed with bovine topical thrombin and calcium chloride. The left maxillary sinus received only autogenous bone, while the right maxillary sinus received a mixture of PRP mixed with autogenous bone, thus each animal acted as its own control. Equal volumes of bone were inserted in each maxillary sinus. Animals were sacrificed at 2, 4, and 8 weeks and all specimens were harvested for peripheral quantitative computed tomography (pQ-CT), static, and dynamic and histomorphometric analysis.
Student t tests were performed comparing bone density via pQ-CT analysis, histomorphometric parameters of total bone area, and bone apposition rate. PRP had no statistically significant effect on bone graft healing in maxillary sinus augmentation when compared using standard pQ-CT, static, and dynamic histologic criteria.
This study fails to find a direct stimulatory effect of PRP on healing of autogenous bone grafts using pQ-CT, static, and dynamic histomorphometric analyses.
... Furthermore, it can inhibit differentiation of osteoclasts and resorption of bone. [8][9][10] One of the problems in allografts is the slow integration of the graft material with the host site (graft-host interface). To solve these problems, growth factors and low-level lasers (LLLs) are used. ...
... To solve these problems, growth factors and low-level lasers (LLLs) are used. [8][9][10][11] LLL accelerate bone generation and wound healing by exerting their effect on mitochondria, production of large amounts of ATP, angiogenesis and by increasing proliferation of osteoblasts, fibroblasts, macrophages, etc. [12][13][14] Various in vivo and in vitro studies have evaluated the photobiostimulatory effects of laser and have reported various results in terms of the laser type, the effects studied, and the tissue in question. 3,15 Considering the safety of LLLs and their ability to accelerate cellular activity and considering the fact that PRF is an autogenous agent rich in different growth factors and is an allograft with good osteoconductive properties, the present study was designed to answer the question whether LLL can improve the quality and quantity of the bone formed. ...
... and even when PRF has been used alone, it has exhibited a good success rate. 8,24 In the present study, the amount of residual graft material in the control group was 29.11 ± 11.79%. Consistent with the results of the present study, Zhang et al. reported that the amount of residual graft material in the deproteinized bovine mineral/ PRP group was 19.16 ± 6.89%. ...
Evaluation of the effect of low-level laser on biomaterials used in maxillary sinus grafts using histological and radiologic examinations: A randomized controlled clinical trial. J Int Oral Health 2016;8(7):801-807. Abstract: Background: One of the techniques suggested for the provision of adequate bone in the maxillary sinus area for placement of endosteal implants with a standard length is to use the sinus lift surgical technique along with autogenous bone graft or bone substitute materials. The aim of this study was an evaluation of the effect of low-level laser on graft materials used for augmentation of the maxillary sinus. Materials and Methods: In the present randomized clinical trial with a split-mouth design, 19 patients aged 30-80 years were evaluated. All the subjects underwent a bimaxillary sinus lift surgical procedure. In the control group, freeze-dried bone allograft (FDBA) and platelet-rich fibrin (PRF) allograft materials were used; in the case group, in addition to the materials mentioned above, low-level 980-nm diode laser beams were applied. Six months after surgery, the density of bone in the augmented area was determined with the cone-beam computed tomography technique. Results: The results showed that the percentages of bone formed in the control and case groups were 20.10 ± 5.67% and 36.26 ± 11.26%, respectively, with a significant difference between the two groups (P < 0.05). There was no significant difference in the means of connective tissue between the two groups (P = 0.612). The Hounsfield unit exhibited a significant difference in relation to the mean bone density within the graft material between the two groups (P = 0.000). Conclusion: Low-level 980-nm diode laser beams can improve the results of treatment rendered with the use of FDBA and PRF.
... The caudal vertebrae in ovariectomized rats exhibit pathologic bone changes consistent with osteoporosis, and represent a valuable and costeffective model for evaluating the performance of potential bioresorbable bone cements engineered for use with osteoplasty (24). Previous studies demonstrated that a substantial effect of PRP might be observed at 2 weeks (25,26). The total bone area and bone formation rate at 2 weeks were much higher than at 4 weeks for maxillary sinus augmentation with PRP incorporated into bone grafts in a rabbit model (25). ...
... Previous studies demonstrated that a substantial effect of PRP might be observed at 2 weeks (25,26). The total bone area and bone formation rate at 2 weeks were much higher than at 4 weeks for maxillary sinus augmentation with PRP incorporated into bone grafts in a rabbit model (25). Also, in combination with autologous bone applied in the forehead area of pigs, a significant accelerating effect of PRP on early bone regeneration (2 weeks) was shown (26). ...
... Considerable research has demonstrated that PRP accelerates new bone formation (13,14,17,26). In spite of the experimental evidence, its use is still a subject of controversy (15,16,25). Several explanations for this debate have been suggested. ...
Background:
Polymethyl methacrylate (PMMA) bone cement is widely used for osteoplasty. However, previous studies have demonstrated the adverse effects of PMMA due to its excessive stiffness and heat production. Recently, calcium phosphate cement (CPC) that overcomes those negative effects has been successfully applied in osteoplasty. The potential problem of CPC is markedly less initial stiffness. It leads to progressive, repeated collapse in the treated vertebra before CPC has been replaced by new bone that would provide substantial improvement in compressive strength and stiffness. The activated platelets in platelet-rich plasma (PRP) release a high concentration of growth factors which play an important role in bone healing.
Objective:
To investigate whether PRP could accelerate the osteoconduction of CPC and enhance the bone strength of the treated vertebra in an animal model.
Study design:
Controlled animal study.
Setting:
Laboratory animal study,
Methods:
Thirty-two female Sprague-Dawley rats were ovariectomized at 8 weeks of age. After 3 months, they were randomly divided into 4 groups and received cement augmentation in the fifth caudal spine with different filler materials; sham-operated rats (S), PMMA (P), CPC (C), and CPC + PRP (CP). Bone mineral density (BMD) and trabecular type-associated morphological parameters, including trabecular bone volume fraction and trabecular thickness in the augmented caudal spine, were evaluated by micro-computed tomography (mirco-CT) 2 weeks after the cementoplasty. Histological analysis was also performed to compare the bone regeneration.
Results:
The trabecular bone volume fraction in the CP group was significantly greater than those of all the other groups. Trabecular thickness was higher in the CP group than the S and P groups. This augmented trabecular structure in the CP group accordingly showed higher BMD. Histological evaluations showed significantly more bone regeneration in the CP group.
Limitations:
There has been a concern that the effect of PRP would be dependent on the species, and might show different results in humans. Baseline values of micro-CT analysis were not measured, which could have provided exact evidence of the changes in trabecular micro-architecture parameters and cement resorption profiles. Finally, caudal vertebrae with filler materials used in biological study should have been compared by their mechanical properties using biomechanical evaluations for a more coherent study, which was not possible due to technical problems.
Conclusions:
Incorporating PRP into CPC could accelerate osteoconduction in the augmented vertebra leading to improvement of trabecular bone microarchitecture and BMD in rats.
... However, the α-CSH properties need to be improved to accelerate better bone healing and regeneration. Platelet-rich plasma (PRP), which is a platelet concentrate containing various autologous growth factors, is often used to promote bone regeneration, although its use still raises various controversies related to the effectiveness of platelet concentrates in wound healing and tissue regeneration [2,6,9,13,[32][33][34][35][36]. Nevertheless, numerous authors stated the potential of autologous platelet concentrate use in several orthopedics and oral surgery scenarios, which not only stimulate bone regeneration but also acted as local hemostatic, facilitate wound-healing, and can be used as medication-related osteonecrosis to reduce pain and increase the quality of life patient [37][38][39][40]. ...
... The rapid regeneration of bone as a result of the combination of PRP and α-CSH provides the advantage of a single-stage dental implant clinical procedure that has the potential to fail due to the lack of osseointegration during the healing period, especially in the installation of dental implants in the maxilla region, which have a lower bone density than the mandible leading to implant instability [8,53]. Moreover, various factors that affect wound healing in the maxillary sinus such as low vascularity, low oxygen pressure, and intra-antral pressure make the use of PRP useful due to accelerating revascularization [6,33]. Several studies also have reported the use of synthetic bone grafts to be ineffective in extensive segmental defects or areas requiring load-bearing resistance due to their weak mechanical strength [54,55]. ...
This study aimed to investigate the effect of combining an innovative bioceramic α-calcium sulfate hemihydrate (α-CSH, CaSO4⋅0.5H2O) bone graft and platelet-rich plasma (PRP) to accelerate bone healing and regeneration in a rabbit model. The bone graft material was implanted bilaterally on rabbit’s artificially maxillary sinus defects: the right maxillary sinus received α-CSH, while α-CSH combine with PRP (α-CSH/PRP) was grafted in left site. The quantity and quality of bone formation after implantation were analyzed radiographically and histologically at 1, 2, and 3 weeks. The micro-computed tomographic results indicated that the bone density of sinus implanted with α-CSH increased and defect volume decreased most after 2 weeks. In histological analysis, both hematoxylin and eosin and Masson trichrome staining of α-CSH/PRP displays better bone healing and regeneration progress than α-CSH after 2 weeks implantation. Therefore, the innovative α-CSH combined with PRP was revealed to be useful in accelerating bone healing and regeneration for the successful defect treatment.
... Moreover, there are contradictory results regarding the synergistic effects of a combination of bioceramics and PRP. 19,20 The objectives of the present study were to determine whether the combination of HA/ ZrO 2 with PRP and HS could exert a synergistic impact on bone regeneration and to compare the in vivo bone regeneration capacity of the HA/ ZrO 2 scaffold with or without PRP. ...
... and P=0.007, respectively). B A has been reported in rabbit defective maxilla regeneration with the same combination, 20 and no synergic effect has been shown by treating the rabbit vertebra with HA granules and PRP. 25 Still, there is other evidence hinting at the formation of fibrous tissue rather than bone in chitosan/ gelatin/platelet/HA-treated defects in rats. 26 Our data also suggested no synergic effect of such a combination. ...
Background:
Platelet-rich plasma (PRP) and bioceramics such as hydroxyapatite (HA) and zirconium oxide (ZrO2) are used to reconstruct mandibular defects. We sought to determine the synergistic effects of HA/ZrO2 and PRP and compare their osteogenic activity.
Methods:
ZrO2 scaffolds were constructed by the slurry method and were then coated with HA and impregnated by PRP/heparan sulfate (HS). Bilateral mandibular defects were created in 26 male rabbits. In 20 rabbits, the left defects were treated with HA/ZrO2/PRP (Group 1) and the corresponding right defects were filled with HA/ZrO2 (Group 2). The 6 remaining models were treated with PRP gels at both sides (Group 3). The osteoconductivity of HA/ZrO2/PRP was compared with that of HA/ZrO2 or PRP by radiological and histological methods after the follow-up period, at weeks 2, 6 and 8. The statistical analyses were performed by ANOVA and LSD using SPSS, version 16.0, for Windows (P<0.05).
Results:
After 2 weeks, the percentage of the surface occupied by bone was significantly higher in the HA/ZrO2/PRP-treated defects than in the PRP-treated defects (P=0.007). Osteoblast and osteocyte counts were higher significantly in the PRP-treated group (P=0.032); however, the cells had not started matrix formation on a large scale and just small islands of osteoid with trapped osteocytes were observed. In the long term, the regenerative potential of all the scaffolds was the same.
Conclusion:
HA/ZrO2 showed a superior osteoconductive capacity over PRP in the short term; however, they showed no long-term synergic effects.
... The present study investigated the efficacy of different graft types in cases of insufficient bone elevation between the maxillary sinus floor and alveolar bone and explored the histomorphometric effect of alendronate sodium trihydrate on grafts after MSFA. Various studies have reported that the rabbit sinus is a suitable model for maxillary sinus augmentation, since both the ostia opening onto the nasal cavity and the air changes inside the nasal cavity are similar to those in humans (28,29). ...
... The combined use of graft materials with different properties and the addition of materials that accelerate bone formation have been explored as methods to hasten healing and prevent graft resorption in bone grafting procedures in the face and jaw regions (29,33). Bisphosphonates are widely used in this context (34)(35)(36)(37)(38). ...
Background:
Increasing sinus pneumatization and the accompanying alveolar bone resorption complicate dental implant placement. This problem can be overcome today by raising the maxillary sinus floor with graft materials. Bisphosphonates are commonly used to accelerate the recovery of the graft materials and to prevent resorption.
Objectives:
The purpose of this study is to investigate whether systemic administration of a bisphosphonate (alendronate) would improve new bone formation and reduce fibrous tissue formation over a 6-week follow-up in rabbits treated with two different grafting materials for maxillary sinus floor augmentation.
Materials and methods:
This experimental animal study was conducted at the Experimental Medical Application and Research Center at Erzurum/ Turkey. Twelve New Zealand rabbits, each weighing between 2.7 and 3.3 kg, were used. Twenty-four maxillary sinus floor elevation operations were performed, two on each animal (n = 24). Each elevation was repaired with either deproteinized bovine bone (xenograft) or autogenous bone graft obtained from the iliac crest. Both groups were divided into 2 subgroups: saline-treated and alendronate-treated. All groups underwent the same surgical procedures and evaluation, and were sacrificed at the 6th postoperative week. Sinuses augmented with deproteinized bovine bone (xenograft) and autogenous bone graft were examined histopathologically and histomorphometrically.
Results:
At 6 weeks, the bone area was significantly larger in the Xenograft-Alendronate group (33.0% ± 5.0%) than in the Xenograft-Saline group (20.8% ± 4.9%) and the bone area was significantly larger in the Autogenous-Alendronate group (43.3% ± 3.8%) than in the Autogenous-Saline group (37.5% ± 6.6%) (P = 0.001). The histomorphometric and histopathological results consistently showed that alendronate stimulated bone formation and reduced fibrous tissue formation in maxillary sinus augmentation grafts, especially in the deproteinized bovine bone group (xenograft).
Conclusions:
Alendronate may be considered a therapeutic option for improving the bone formation process and reducing resorption in different bone grafting procedures. Further detailed studies should focus on dosage and time-dependent effects of alendronate on bone remodeling.
... Se ha señalado que, dentro de los tipos de biomateriales antes citados, los injertos óseos obtenidos del propio paciente serían los que poseen un mejor pronóstico (Anitua et al.;Wong & Rabie, 1999;Rabie et al., 2000;Kim et al., 2001;Lu et al., 2002;Zoricic et al., 2002;Bidic et al., 2003;Cordioli et al., 2003;Butterfield et al., 2004;Chacón et al., 2004); Stubbs et al., 2004;Donos et al., 2005;Wong et al., 2005;Okazaki et al., 2005), transformándose en el material de referencia (Gold Standard) a la hora de probar biomateriales en regeneración ósea (Olate et al.). De hecho, los AI de origen endocondral (EC) e intramembranoso (IM) presentan, respectivamente, un 357% y un 642% más de formación ósea que un AL de tipo IM (Lu & Rabie 2002). ...
... Si bien es cierto, la evidencia señala que las posibilidades de éxito con AI son altas, existen factores a considerar que sería limitante a su uso: el abastecimiento y disponibilidad son limitados, por lo que, en ocasiones, es necesario utilizar biomateriales como sustitutos óseos (Wong & Rabie, 1999;Rabbie et al., 2000a,b;Lu et al., 2002;Donos et al.;Lu et al., 2004;Bidic et al.;Zoricic et al.;Butterfield et al.;Kim et al.;Stubbs et al.;Wong et al., 2005;Okazaki et al.;Cordioli et al.;Chacón et al.). ...
Dental caries and periodontal disease are public heath problems. 100% of people from low-medium and low socio economic levels have caries. 92.19% of people between 35 and 74 years of age have periodontal disease. Both pathologies may cause teeth fall down. Titanium implants could improve prognosis of prosthetics treatments, but frequently requires increase bone volume, to restore shape and function. The research wants to know state of art in use of biomaterials in bone regeneration. Best biomaterial properties were shown by autologous bone (AB), however, do exist alternatives such as allograft (AL) and bone matrix (BM). AB has shown best prognosis, from endochondral (EC) and intramembranous (IM), with 357% and 642% most bone formation compared to AL IM. AB IM type is successfully compared to EC (IM shown 166% more bone formation). AB access is limited, this fact have made necessary use other biomaterials. AL combined with BM produce 224% more bone compared to AL. Membrane use improves long term stability of IM and EC bone. AB EC type is the most successful biomaterial. Considering limited access to this bone, it could be used combined with bone matrix. Membranes have shown increase long term stability of biomaterials.
... A few authors have reported a positive influence of PLG on bone regeneration in humans undergoing orthopedic (194,195) surgery and only an early effect (after 3 months) in maxillofacial surgery (196). On the other hand, our results are in agreement with a number of clinical and experimental studies demonstrating no additional effect of PLG on bone healing (197)(198)(199). Also, in vitro experiments are ambiguous with respect to a dose-dependent mitogenic and chemotactic effect of PLG on BMSCs (107) and osteoblast-like cells (108), whereas osteogenic differentiation was inhibited (109). ...
... In our studies we used goat PLG and we did not study bone formation in the first three weeks of implantation. On the other hand, a number of clinical and experimental studies demonstrate the absence of PLG stimulation of bone healing (197)(198)(199)277). Also, in vitro experiments are ambiguous with respect to a dose-dependent mitogenic and chemotactic effect of PLG on MSCs (107) and osteoblast-like cells (108), while osteogenic differentiation was either inhibited (109) or absent (278). ...
... Butterfield et al. and reported identical outcomes in PRP's efficacy in sinus augmentation in the rabbit model. 19 Numerous studies have assessed the efficacy of PRP as an adjunct to anorganic bone such as Bio-Oss. Kim et al. grafted cranial defects in 20 rabbits with Bio-Oss and PRP. ...
... Finally, a mixture of calcium chloride (Merck, Cat. No. 102382) /topical bovine thrombin (T-4648, Sigma-Aldrich) (10 CC of 10% calcium chloride mixed with 10,000 units of topical bovine thrombin) was added to the platelet-enriched fibrinogen solution (35,36) to organize PFG prior to operation. ...
Background:
Healing of large segmental bone defects can be challenging for orthopedic surgeons. This research was conducted to provide further insight into the effects of BMP7 in combination with autograft and platelet fibrin glue (PFG) on bone regeneration by Masquelet technique (MT).
Methods:
Twenty five domestic male rabbits, more than 6 months old, weighing 2.00±0.25 kg were randomly divided into five equal groups as follows: MT-blank cavity (without any biological or synthetic materials) (1), blank cavity (2), MT-autograft (3), MT-autograft-BMP7 (4), and MT-BMP7-PFG (5). A 20 mm segmental defect was made in radial bone in both forelimbs. The Masquelet technique was done in all groups except group 2. The study was evaluated by radiology, biomechanics, histopathology and scanning electron microscopy.
Results:
The results showed that Masquelet technique enhanced the healing process, as, the structural and functional criteria of the injured bone showed significantly improved bone healing (P<0.05). Treatment by PFG-BMP7, Autograft-BMP7, and autograft demonstrated beneficial effects on bone healing. However, Autograft-BMP7 was more effective than autograft in healing of the radial defect in rabbits.
Conclusion:
Our findings introduce the osteogenic materials in combination with Masquelet technique as an alternative for reconstruction of the big diaphyseal defects in the long bones in animal models. Our findings may be useful for clinical application in future.
... Although the rabbit sinus cavity shows similarities to the human maxillary sinus, it differs in the number of platelets. Coagulation factors in rabbit blood are more abundant than in human blood, making the healing pattern presented in the rabbit faster than that which occurs in humans (Butterfield et al., 2005). However, because of ethical issues, this procedure has not been adopted clinically. ...
Background
Schneiderian membrane (SM) perforation is a major complication of maxillary sinus elevation with simultaneous bone grafting, yet under this scenario there is no standard biomaterial that maximizes favorable tissue healing and osteogenic effects.
Purpose
To compare the effect of advanced platelet-rich fibrin (A-PRF) and collagen membrane (CM) on a perforated SM with simultaneous bone grafting in a maxillary sinus elevation model.
Materials and Methods
After perforation of the SM was established, 24 animals were randomly divided into two groups: (i) group CM: CM and deproteinized bovine bone mineral (DBBM) (n = 12), (ii) group A-PRF: A-PRF and DBBM (n = 12). Radiographic and histological evaluations were performed at 1 and 4 weeks post-operation.
Results
At 1 week, an intact SM was found in group A-PRF. At each time point, the number of inflammatory cells at the perforated site was higher in group CM, and the area of new osteoid formation was significantly greater in group A-PRF (p < 0.0001). At 4 weeks, the osteogenic pattern was shown as from the periphery to the center of the sinus cavity in group A-PRF.
Conclusion
The higher elasticity, matching degradability, and plentiful growth factors of A-PRF resulted in a fully repaired SM, which later ensured the two osteogenic sources from the SM to generate significant new bone formation. Thus, A-PRF can be considered to be a useful bioactive tissue-healing biomaterial for SM perforation with simultaneous bone grafting.
... This early effect is attributed to short lifespan of the platelet due to early dissolution of fibrin and growth factors. This explanation is in concordance with many authors (56)(57)(58)(59)(60)(61)(62) . Decrease bone density at six months post-operatively in group II (PRP) can be attributed to the fast degradation rate of the fibrin and the dissolution of PRP. ...
... The collagen membrane used in this study seems to be useful to survive PRP in the injured pulp tissues as much as possible and to accelerate and promote regeneration that may improve dramatically the clinical outcome (35,36) . Also, it was found that the active secretion of PRP's stored GFs (70%) starts within 10 min, approximating 100% within the first hour (32) . ...
Background: To overcome the disadvantages of various synthetic-based biomaterials used in
pulp therapy, the researchers are directed towards innovation of novel materials that are biologically
compatible. Platelet-rich plasma (PRP) is considered one of the novel biologically-based autologous
substitutes.
Purpose: To evaluate histopathologically the pulp response to the platelet-rich plasma as a
pulpotomy medicament in primary teeth.
Materials and methods: A total of 30 healthy lower first primary molars and canines that
indicated for serial extraction were selected for this experiment. PRP and formocresol pulpotomies
were performed (12 teeth/each group), where the other 6 teeth were used as a control. Four teeth
from each experimental group and one control were extracted at post-treatment intervals; 14
days, one and three months. The samples were prepared and the tissues’ sections were stained
with Hematoxylin & Eosin for histopathological evaluation. Using ordinary light microscope, all
sections were histopathologically analyzed blindly in terms of soft tissues organization, degree of
inflammatory reaction, hyperemic changes, pulp necrosis and dentin bridge formation.
Statistical analysis: All data were analyzed with the Mann-Whitney U-test and the probability
level of significance was accepted at p < 0.05.
Results: The overall histopathological results of pulp response to PRP were statistically
significant in terms of soft tissue organization, degrees of inflammation, hyperemia, and pulp
necrosis than formocresol (p < 0.05).
Conclusion: Histopathologically, it was concluded that PRP had induced significantly a
successful healing biologic response than synthetic formacresol; serving as a potent autogenous
pulpotomy medicament alternative to formocresol.
KEYWORDS: Platelet-rich Plasma, Histopathological response, Formocresol pulpotomy,
Primary dentition.
... In literature, there are conflicting results [146,147] about the use of PRP in bone regeneration. Bianco et al. have suggested that PRP seems to be more effective than single recombinant GFs due to the synergism among all GFs [148]. ...
The regenerative medicine, a new discipline that merges biological sciences and the fundamental of engineering to develop biological substitutes, has greatly benefited from recent advances in the material engineering and the role of stem cells in tissue regeneration. Regenerative medicine strategies, involving the combination of biomaterials/scaffolds, cells, and bioactive agents, have been of great interest especially for the repair of damaged bone and bone regrowth. In the last few years, the life expectancy of our population has progressively increased. Aging has highlighted the need for intervention on human bone with biocompatible materials that show high performance for the regeneration of the bone, efficiently and in a short time. In this review, the different aspects of tissue engineering applied to bone engineering were taken into consideration. The first part of this review introduces the bone cellular biology/molecular genetics. Data on biomaterials, stem cells, and specific growth factors for the bone regrowth are reported in this review.
... In immediately placed implants in dogs, the addition of L-PRF in the socket resulted in significantly increased bone formation compared to empty sockets (Neiva et al., 2016). In rabbit and sheep sinus augmentation models, adding PRP to autogenous grafts (Jakse et al., 2003, Butterfield et al., 2005, Trindade-Suedam et al., 2010 or to a bone allograft (Grageda et al., 2005) did not result in additional benefits. Moreover, sinus floor elevation with PRP combined with MSCs or with an autologous particulate cancellous bone and marrow graft resulted in a similar gain in bone volume and height (Ohya et al., 2005). ...
Aim
This review critically appraises the available knowledge on the pre‐clinical and clinical use of bioactive factors for bone regeneration in the cranial and maxillo‐facial area.
Materials and Methods
The use of growth factors, amelogenins and autologous platelet concentrates (APCs) for bone regeneration was reviewed in a systematic manner. More specifically, preclinical and clinical studies on ridge preservation, alveolar ridge augmentation, regeneration of peri‐implant defects and sinus augmentation models were considered.
Results
Amongst different bioactive factors, the highest pre‐clinical and clinical evidence of a positive effect on bone formation is associated with BMP‐2 and the lowest with amelogenins. While APCs seem to accelerate clinical healing and reduce postoperative discomfort, there is insufficient and contrasting evidence of a significant effect on hard tissue regeneration for the different clinical applications.
Conclusions
Although there is increasing evidence that bioactive factors might enhance the bone regeneration process, the great heterogeneity of the available studies and the limited number of RCTs do not allow to draw robust conclusions. Issues that still need to be investigated include the optimal carriers for bioactive agents (direct vs. indirect), the dosage, the timing of administration, as well as the possibility of combining different agents to promote synergistic effects.
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... A reduced healing time (50%) has been shown in a study of Kassolis and Reynolds (2005). In animal studies no statistically significant difference was found between cancellous bone graft material with and without PRP (Butterfield et al. 2005;Jakse et al. 2003). ...
Chemical cleaning procedures of allografts are destroying viable bone cells and denaturing osteoconductive and osteoinductive proteins present in the graft. The aim of the study was to investigate the mechanical differences of chemical cleaned allografts by adding blood, clotted blood; platelet concentrate and platelet gel using a uniaxial compression test. The allografts were chemically cleaned, dried and standardized according to their grain size distribution. Uniaxial compression test was carried out for the four groups before and after compacting the allografts. No statistically significant difference was found between native allografts, allografts mixed with blood, clotted blood, platelet concentrate and platelet concentrate gel regarding their yield limit after compaction. The authors recommend to chemical clean allografts for large defects, optimize their grain size distribution and add platelet concentrate or platelet rich plasma for enhancing as well primary stability as well bone ingrowth.
... The hybrid FPG-containing scaffolds were prepared as follows: The Gel/nHA, Gel/nHA/SNPs, Gel/nHA/GNPs and Gel/nHA/SNPs/ GNPs scaffolds, sterilized previously with 60 Co γ-ray irradiation, were infused with 0.1 ml platelet enriched fibrinogen solution for 5 min, then with 0.1 ml calcium chloride (Merck, Cat. No. 102382)/topical bovine thrombin (T-4648, Sigma-Aldrich) (10 CC of 10% calcium chloride mixed with 10,000 units of topical bovine thrombin) for preparation of FPG [21,22]. After complete reaction for 30 min at room temperature, the hybrid scaffolds were freeze-dried at -20°C for 48 h and kept in vacuumed packs until further use [6]. ...
A new composition of platelet-fibrin glue (FPG), gelatin (Gel), nanohydroxyapatite (nHA), silver nanoparticles (SNPs) and gold nanoparticles (GNPs) was synthesized and employed in preparation of hybrid scaffolds and was applied in bone tissue engineering in the surgically critical-sized bone defect in a rat model. Sixty bilateral radial bone defects were randomly divided into six groups including untreated defects, autograft and those treated with Gel/FPG/nHA containing scaffolds including nHA alone, nHA/SNPs, nHA/GNPs and nHA/SNPs/GNPs (n=10 in each group). The defects were assessed by radiography, histopathology, scanning electron microscopy and biomechanical testing. In comparison with the untreated defects, all the treated defects demonstrated significantly superior new bone formation, remodeling and bone tissue volume. Moreover, the defects treated with GNPs showed significantly higher ultimate strength, yield strength and stiffness. The nHA and nHA/SNPs moderately improved bone regeneration that were not close to the autograft in some parameters, whereas nHA/GNPs and nHA/SNPs/ GNPs significantly improved bone healing closely comparable with those of the autograft group in most parameters. In conclusion, although all the scaffolds had some beneficial effectiveness on bone regeneration, the scaffolds containing GNPs were more effective in improving the structural and functional properties of the newly formed bone and were more osteoinductive than other scaffolds and were comparable to the autograft. Therefore, the scaffolds including GNPs can be regarded as a promising option to be used in bone tissue engineering.
... Finally, the platelet enrich fibrinogen solution was mixed with a combination of calcium chloride (Merck, Cat. No. 102382)/topical bovine thrombin (T-4648, Sigma-Aldrich) (10 CC of 10% calcium chloride mixed with 10,000 units of topical bovine thrombin) (Butterfield et al. 2005;Findikcioglu et al. 2009) for preparation of FPG prior to operation. ...
Fibrin-platelet glue (FPG) is a blood derivative, in which platelets and fibrinogen are concentrated in a small plasma volume, by differential centrifugation and precipitation. It can form a three-dimensional and biocompatible fibrin scaffold with a myriad of growth factors and proteins that are released progressively to the local environment and contribute to the accelerated postoperative bone healing. Gelatin (Gel) is a derivative of collagen and can promote cell adhesion and proliferation due to its unique sequence of amino acids, so it is suitable for bone tissue applications. This study examined the effects of Gel, FPG and their combinations as bone scaffold on the healing of surgically created critical-size defects in rat radius. Fifty critical size defects of 5 mm long were bilaterally created in the radial diaphysis of 25 rats. The animals were randomly divided into five equal groups as empty defect, autograft, Gel, FPG and Gel–FPG groups (n = 10 in each group). Radiographs of each forelimb were taken postoperatively on the 1st day and then at the 28th and 56th days post injury to evaluate bone formation, union and remodeling of the defect. After 56 days, the rats were euthanized and their harvested healing bone samples were evaluated by histopathology, scanning electron microscopy (SEM) and biomechanical testing. The results of present study showed that the Gel alone did not significantly affect bone healing and regeneration; however, the Gel treated defects promoted healing more than those that were left untreated (negative control). Furthermore, the FPG-enhanced grafts provided a good scaffold containing numerous growth factors for proliferation of osteoinduction and was effective in improving the structural and functional properties of the newly formed bone more than that of the untreated and also the Gel treated groups. Incorporation of Gel into the FPG scaffold improved healing potential of the FPG scaffold; however, it was still inferior to the autograft (positive control). Although the Gel–FPG scaffolds had best effectiveness during bone regeneration, it still needs to be further enhanced by incorporation of the ceramic and osteoinductive biomaterials.
... Several basic growth factors secreted from de-granulated platelets include platelet-derived growth factor (PDGF), transforming growth factor (TGF), vascular endothelial growth factor (VEGF) and insulin-like growth factor-1 (IGF-1) which can then bind to their receptors on mesenchymal stem cells (MSCs), fibroblasts, osteoblasts and endothelial cells and thus, perform their effect on tissue repair and recovery (10). Although some evidence on the positive effect of PRP in bone tissue regeneration has been reported, further studies have come to conflicting results (11,12). Thus, it seems that more investigations about the aptitude of PRP on osteogenesis is required. ...
Background:
Due to the known disadvantages of autologous bone grafting, tissue engineering approaches have become an attractive method for ridge augmentation in dentistry. To the best of our knowledge, this is the first study conducted to evaluate the potential therapeutic capacity of PRP-assisted hADSCs seeded on HA/TCP granules on regenerative healing response of canine alveolar surgical bone defects. This could offer a great advantage to alternative approaches of bone tissue healing-induced therapies at clinically chair-side procedures.
Methods:
Cylindrical through-and-through defects were drilled in the mandibular plate of 5 mongrel dogs and filled randomly as following: I- autologous crushed mandibular bone, II- no filling material, III- HA/TCP granules in combination with PRP, and IV- PRP-enriched hADSCs seeded on HA/TCP granules. After the completion of an 8-week period of healing, radiographic, histological and histomorphometrical analysis of osteocyte number, newly-formed vessels and marrow spaces were used for evaluation and comparison of the mentioned groups. Furthermore, the buccal side of mandibular alveolar bone of every individual animal was drilled as normal control samples (n=5).
Results:
Our results revealed that hADSCs subcultured on HA/TCP granules in combination with PRP significantly promoted bone tissue regeneration as compared with those defects treated only with PRP and HA/TCP granules (P<0.05).
Conclusion:
In conclusion, our results indicated that application of PRP-assisted hADSCs could induce bone tissue regeneration in canine alveolar bone defects and thus, present a helpful alternative in bone tissue regeneration.
... To fabricate the FPG-containing hybrid scaffolds, the nHA and Gel-nHA scaffolds, sterilized previously with 60 Co γ-ray irradiation, were infused with 0.1 ml platelet enriched fibrinogen solution for 5 min, then with 0.1 ml calcium chloride (Merck, Cat. No. 102382)/ topical bovine thrombin (T-4648, Sigma-Aldrich) (10 ml of 10% calcium chloride mixed with 10,000 units of topical bovine thrombin) for preparation of FPG (26,27). After complete reaction for 30 min at room temperature, the hybrid scaffolds were freezedried at −20°C for 48 h and kept in vacuumed packs until further use (11). ...
Different biomaterials have been used in orthopedic surgery. Evaluation of biomaterials for bone healing promotion has been a wide area of research of the orthopedic field. Sixty critical size defects of 5 mm long were bilaterally created in the radial diaphysis of 30 rats. The animals were randomly divided into six equal groups as empty defect, autograft, nanohydroxyapatite (nHA), Gelatin (Gel)-nHA, Fibrin-platelet glue (FPG)-nHA and Gel-FPG-nHA groups (n = 10 in each group). Radiographs of each forelimb were taken postoperatively on the 1st day and then at the 28th and 56th days post injury. After 56 days, the rats were euthanized and their harvested healing bone samples were evaluated by histopathology, scanning electron microscopy and biomechanical testing.
All the treated defects demonstrated significantly superior new bone formation, remodeling and bone tissue volume. Moreover, the defects treated with FPG-nHA showed significantly higher ultimate load, yield load and stiffness. The Gel-FPG-nHA moderately improved bone regeneration that was not close to the autograft in some parameters, whereas FPG-nHA significantly improved bone healing closely comparable with the autograft group in most parameters. In conclusion, although all the nHA containing scaffolds had some beneficial effects on bone regeneration, the FPG-nHA scaffold was more effective in improving the structural and functional properties of the newly formed bone and was more osteoinductive than the Gel and was comparable to the autograft. Therefore, the FPG can be regarded as a promising option to be used in conjunction with mineral scaffolds on bone tissue engineering.
... Coagulation factors in rabbit blood are more prevalent than in human blood. The concentration of platelets in normal rabbit blood is 468,000 ± 182,000/mm 3 , whilst the number of normal platelets in human blood is 150,000e400,000/mm 3 (Butterfield et al., 2005). The higher concentration of platelets makes the rabbit healing pattern faster than in the human. ...
The aim of the present study was to evaluate the effectiveness of platelet-rich fibrin (PRF) in repairing of Schneiderian membrane perforations in rabbit’s maxillary sinus. A total of 42 female New Zealand rabbits were randomly divided into two groups. Symmetrical bony defects were created 1 cm in diameter and the sinus membranes were exposed. The Schneiderian membranes were elevated in both sinuses and each membrane was perforated with a 1 cm incision. No treatment was applied to the right perforations in both groups. Left-sided perforations were closed with collagen membrane in the first group and PRF membrane in the other group. Seven animals randomly selected from each group were sacrificed at weeks 1, 2 and 4 in order to be able to examine the amounts of lymphocytes, fibroblasts, veins and collagen fibers in the area where the membranes were applied. Histological analyzes showed that there were no statistically significant differences between the collagen membrane and the PRF membrane in the healing of sinus perforation area. PRF may be considered as an alternative application to collagen membrane in sinus membrane perforations.
... A major rate-limiting step in the induction of nerve regeneration across a gap is the proliferation, and migration of Schwann cells between the nerve stumps. Therefore, formation of a properly aligned extra cellular matrix scaffold is essential to enhance Schwann cell proliferation in a conduit, through which blood vessels and other cell types migrate and form primordial assembly for the formation of a new nerve structure [34]. We used a silicone rubber chamber as a conduit to provide a scaffold for PRP and to facilitate Schwann cells migration. ...
Objective:
To determine the effects of local administration of platelet rich plasma (PRP) on peripheral nerve regeneration in rat sciatic nerve transection model.
Methods:
Forty-five male white Wistar rats were randomized into three experimental groups (n=15): Normal control group (NC), silicon group (SIL), PRP treated group (SIL/PRP). In NC group left sciatic nerve was exposed through a gluteal muscle incision and after homeostasis muscle was sutured. In SIL group left sciatic nerve was exposed the same way and transected proximal to tibio-peroneal bifurcation leaving a 10-mm gap. Proximal and distal stumps were each inserted into a silicone conduit and filled with 10 µL phosphate buffered solution. In SIL/PRP group silicon conduit was filled with 20 µL PRP. Each group was subdivided into three subgroups of five animals each and were studied 4, 8, 12 weeks after surgery.
Results:
The animals were comparable regarding the baseline characteristics. Behavioral testing, sciatic nerve functional study and gastrocnemius muscle mass showed earlier regeneration of axons in SIL/PRP than in SIL group.
Conclusion:
Local administration of PRP combined with silicon grafting could accelerate functional recovery of peripheral nerve. Easily available growth factors and bioactive proteins present in PRP may have clinical implications for the surgical management of patients after nerve transection.
... However, a limitation of this study could be the different (faster) rhythm of bone healing in rabbits compared to humans. (27)(28)(29) In the study, postoperative external immobilisation was not used in the rabbit forearm with the defect. The integrity of the radius and the strong fibro-osseous radioulnar union proximal and distal to the skeletal defect provided mechanical stability. ...
Introduction:
This study evaluates the effect of autologous platelet-rich plasma (PRP) combined with xenogeneic demineralised bone matrix (DBM) on bone healing of critical-size ulnar defects (2-2.5 times the ulnar diameter) in New Zealand White rabbits.
Methods:
Critical-size defects were created unilaterally in the ulna of 36 rabbits, while keeping the contralateral limb intact. They were divided into three groups. In Group A, the defect was filled with autologous PRP and in Group B, with autologous PRP combined with DBM; in Group C, the defect remained empty. The rabbits were euthanised 12 weeks postoperatively. Radiological, biomechanical and histological assessments were carried out and statistical analysis of the results was performed.
Results:
Group B had significantly higher radiological and histological scores than Groups A and C. Defects in Group B showed significant new bone formation, whereas there was minimal or no new bone formation in Groups A and C. Only specimens in Group B showed macroscopic bone union. Biomechanical evaluation of the treated and intact contralateral limbs in Group B showed significant differences.
Conclusion:
In this study, statistically significant enhancement of bone healing was found in critical-size defects treated with PRP and DBM, as shown by radiological findings, gross assessment, and biomechanical and histopathological results. Defects in the two other groups remained unbridged. Therefore, PRP was effective only when it was used in combination with a bone graft.
... [9] Aghaloo and Butterfield study of bone grafts and PRP application failed to show superiority of PRP; however, there are also studies showing accelerated advancement of bone tissue when PRP is used with the grafts used in dentistry for osteointegration, and there are also reports on successful outcomes in maxillary arthroplasty. [8,32,43] Ulus PRP has been used together with autograft and hydroxyapatite in patients undergoing lumbar spinal fusion, and both favorable and unfavorable outcomes have been reported. [44,45] Siebrecht et al. showed that PRP increased tissue ingrowth and ossification inside porous hydroxyapatite, and they also reported increased tensile strength and callus of Achilles tendon of rats after PRP application. ...
Background: Delayed union of fractured bone is one of the main problems of orthopedics and traumatology practice. It was hypothesized that the beneficial effects of allogeneic platelet-rich plasma (PRP) would be valuable in the treatment of segmental bone defects. This study is a comparison of the effects of demineralized bone matrix (DBM) and PRP in a segmental bone defect model. Methods: Total of 48 Wistar albino rats were separated into 4 groups. Segmental bone defect was created at right radius diaphysis in all specimens using dorsal approach. Four additional rats were used as PRP source. Intracardiac blood was withdrawn before the operation for preparation of allogeneic PRP. Group 1 (n=12) served as control group and defects were left untreated. Group 2 (n=12), was PRP group, and received grafting with PRP. Group 3 (n=12) was PRP+DBM combination group, and was treated with grafting and mixture of DBM and PRP. In Group 4 (n=12), defect area was grafted with DBM only. At the end of 10th week, rats were sacrificed, forearms were dissected, and defect areas were examined with radiological and histopathological parameters. Results: Radiological evaluation revealed that ossification was best in PRP group, followed by DBM group. According to results of histopathological studies, union quality was better than control group in all treatment groups (Groups 2, 3, and 4), and was best in PRP group (p<0.05). Results were also better in PRP group when examined in terms of cortex development and remodeling (p<0.05). When examined in terms of new osteogenesis, results were comparable in Groups 2, 3, and 4, but all were better than control group. Conclusion: It was concluded that PRP and DBM have comparable effect on recovery of defective bones, but there is no synergistic effect when used together. We believe that PRP can be a cost-effective, readily available alternative to DBM with minimal morbidity.
... Osseointegrated implants are considered the ideal replacement for tooth loss; however, the success of an implant is related to the bone resorption in edentulous sites (Butterfield et al., 2004;Adeyemo et al., 2008). Alveolar resorption is a chronic, accumulative, irreversible and progressive disease, leading to esthetic and functional problems for implant installation (Wu et al., 2008). ...
Autogenous bone grafts are considered to be the gold standard in bone regeneration because of their osteogenic activity; however, due to limited availability of intraoral donor sites and the need to resolve the demands of patients requires an alternative to these. Two male patients were submitted to implant surgery in two stages with 6 months intervals between each of them: the first was exodontia and placement of DBM graft into the socket; the second stage was the drill with a 2 mm internal diameter trephine in center of the alveolar ridge previously grafted with DBM and subsequent implant placement. The samples were analyzed under histological techniques. A very mature bone was observed at 6 months after DBM graft placement in the sockets, showing it to be a good alternative as bone graft.
... Previous studies found in the literature concerning the use of hydrogels based only on PRP, mostly report the activation with bovine thrombin and crosslinking with calcium [50,51]. Despite the potential of those systems, the contraction observed in most of them during the culture period results in an ineffective strategy. ...
The role of Platelet Lysates (PLs) as a source of growth factors (GFs) and as main element of three-dimensional (3D) hydrogels has been previously described. However, the resulting hydrogels usually suffer from high degree of contraction, limiting their usefulness. This work describes the development of a stable biomimetic 3D hydrogel structure based on PLs, through the spontaneous assembling of a high concentration of chitosan-chondroitin sulfate nanoparticles (CH/CS NPs) with PLs loaded by adsorption. The interactions between the NPs and the lysates resemble the ones observed in the extracellular matrix (ECM) native environment between glycosaminoglycans and ECM proteins. In vitro release studies were carried out focusing on the quantification of PDGF-BB and TGF-β1 GFs. Human adipose derived stem cells (hASCs) were entrapped in these 3D hydrogels and cultured in vitro under chondrogenic stimulus, in order to assess their potential use for cartilage regeneration. Histological, immunohistological and gene expression analysis demonstrated that the PLs-assembled constructs entrapping hASCs exhibited results similar to the positive control (hASCS cultured in pellets), concerning the levels of collagen II expression and immunolocalisation of collagen type I and II and aggrecan. Moreover, the deposition of new cartilage ECM was detected by alcian blue and safranin-O positive stainings. This work demonstrates the potential of PLs to act simultaneously as a source/carrier of GFs and as a 3D structure of support, through the application of a "bottom-up" approach involving the assembly of NPs, resulting in an enriched construct for cartilage regeneration applications.
Copyright © 2015. Published by Elsevier Ltd.
... According to our study and other similar studies [17], it seems that the use of EMD has better score results in terms of inflammatory response than the use of Ca(OH) 2 in rat dental pulps (Tables 3 and 4). In animal studies using PRP, when chancellors bone from the iliac crest was used as the graft material for sinus lifts with or without PRP, biopsies showed both PRP and control groups achieved similar results with no statistically significant difference between the two [34, 35]. Similar findings were also reported when PRP was added to the xenograft [36] (e.g., Bovine HA). ...
Aims: To evaluate the inflammatory response of the exposed pulp of incisor teeth in rats after direct pulp capping, using platelet rich plasma (PRP), enamel matrix derivate (EMD), mineral trioxide aggregate (MTA) and calcium hydroxide (Ca(OH)2).
Methods: The study was conducted on 36 Wistar albino rats with a total of 144 incisor teeth. The pulps of 96 teeth of the rats were perforated and capped with different agents. Serving as the positive control group, the pulps of 24 teeth were only perforated and capped without capping agents, whereas the pulps of 24 teeth were us- ed as the negative control group without being perfo- rated (without any process). The research was ended with the extracting of the teeth on the 7th day - 28th day. The teeth were taken to the routine and histolo- gical follows; cross sections were prepared and pain- ted with hematoxylen & eosin. All of the sections were evaluated in terms of inflammatory reaction by his- tologic analysis taken by light microscope. Statistical analysis was used. The normal distribution of all data was tested with the Mann Whitney U and the differences between the groups were analyze dusing Kru- skal Wallis test at 0.05 level.
Results: There are no statistically significant differences in terms of inflam- mation type and necrosis among the treatment groups on 7 days’ post capping. However, improved inflam- matory cell accumulation, hyperemia and lowest ne- crosis were observed from the samples treated with PRP (p < 0.05). Conversely, the EMD group indicated that the criteria of inflammation scores and hyperemia were higher in the 28th day (p < 0.05).
Conclusions: Most of cells accumulating in the PRP group and most necrosis were seen in the EMD group. These new PRP materials might serve as pulp capping bio- materials to induce initial healing response in the fu- ture.
... Osseointegrated implants are considered the ideal replacement for tooth loss [1]; however, the success of an implant is related to the bone resorption in edentulous sites [2]. It is very important to note that bone is a living tissue that constantly is being remodeled [3]. ...
Regeneration of resorbed edentulous sites can be induced by bone grafts from the subject himself and/ or by the use of biomaterials. At present, there has been an extensive search for biomaterials that are evaluated by artificially creating one or more critical defects. The aim of this work was to clinically and radiographically analyze bone formation by the use of some biomaterials in artificially created defects in the parietal bone of rabbits. Six rab- bits were used, creating defects of 8 mm in diameter in parietal bones. One defect was maintained with coagulum only, and in others, freeze-dried bone allograft (FDBA), autologous bone, and a combination of autologous bone with FDBA respectively, were added. Animals were sacrificed at 15-90 days with 2 weeks interval each, and calvaria were analyzed macroscopically, measuring by digital caliper the lack of filling at the surface of defects, identifying limits at anteroposterior and coronal view, realizing a digital photograph register of their external surfaces. This was subsequently evaluated radiographically by occlusal film radiography used to quantify its density through software. In conclusion, autologous bone showed the best behavior, clinically as well as radiographically. However, FDBA is a good option as an alternative to autologous bone as its behavior was slightly lower over time. The combination of autologous bone and FDBA in the same defect showed results considerably inferior to grafts used separately. Low radiopacity and clear limits were observed through time for the control coagulum filled defect.
... Osseointegrated implants are considered the ideal replacement for tooth loss; however, the success of an implant is related to the bone resorption in edentulous sites (Butterfield et al., 2004;Adeyemo et al., 2008). Alveolar resorption is a chronic, accumulative, irreversible and progressive disease, leading to esthetic and functional problems for implant installation (Wu et al., 2008). ...
Autogenous bone grafts are considered to be the gold standard in bone regeneration because of their osteogenic activity; however, due to limited availability of intraoral donor sites and the need to resolve the demands of patients requires an alternative to these. Two male patients were submitted to implant surgery in two stages with 6 months intervals between each of them: the first was exodontia and placement of DBM graft into the socket; the second stage was the drill with a 2 mm internal diameter trephine in center of the alveolar ridge previously grafted with DBM and subsequent implant placement. The samples were analyzed under histological techniques. A very mature bone was observed at 6 months after DBM graft placement in the sockets, showing it to be a good alternative as bone graft.
... As informações obtidas neste trabalho auxiliam na escolha da melhor técnica de centrifugação para obtenção do PRP para o uso na medicina equina, justiϐicada pelos resultados contrastantes do efeito biológico do PRP na reparação tecidual em função da ausência de protocolos padronizados (Anitua et al. 2006). Tais estudos descrevem diversas velocidades de centrifugação, locais de colheita de sangue, volumes de sangue necessários, proporções do plasma considerados como PRP e substâncias para geliϐicar o PRP (Aghaloo et al. 2002, Butterϐield et al. 2005, o que propicia grande variação na concentração das plaquetas, podendo inϐluenciar nos diferentes efeitos biológicos in vivo (Anitua et al. 2006). Dentro os diversos tipos de anticoagulantes o citrato de sódio foi o escolhido por preservar a integridade da membrana das plaquetas, sendo o mais adequado no preparo do PRP (Marx 2000a, Trindade-Suedam et al. 2007). ...
Platelet-rich plasma (PRP) is a prepared of the whole blood which contains several growth factors responsible for cellular proliferation and differentiation, angiogenesis, and for the increase of the extracellular matrix. Thus, the aim of this study was to test 10 different centrifugation protocols to obtain PRP from the whole blood of healthy equines. Ten samples of 27mL of the whole blood of 5 healthy equines were used, which were centrifuged in accordance to the proposed protocols. The results showed that the protocols with less relative centrifugation force resulted in greater (p<0,05) platelets concentration. Also, platelets concentration was not influenced by varying the time of centrifugation. However, time did affect the number of leukocytes in some protocols. The best four protocols were analyzed by ELISA test to quantitate the amount of TGF-β, which revealed no difference (p> 0.05) between the protocols.
... PRP is not only easy to obtain and produce, but also safe [2,3]. In many literatures, PRP has been used to improve bone healing in the fields of orthopaedic and maxillofacial surgeries; however, reports on the benefits of this material have not been conclusive as there have been contradictory outcomes, which report both good and poor results [2][3][4][5][6][7][8]. ...
Background: This study was carried out to evaluation the effect of human platelet rich plasma (hPRP) on the bone repair process in rabbit model which could be used in many procedures of orthopedic or maxillofacial bone and implant reconstructive surgery.
Materials and Methods: This study is a prospective experimental study on animal model. A critical size defect (10 mm) was created in the radial diaphysis of 24 rabbit and then supplied with human PRP (treatment group) or the defect left empty (control group). Radiographs of each forelimb was taken postoperatively on 1st day and at the 2nd, 4th, 6th and 8th weeks post injury to evaluate bone formation, union and remodeling of the defect. The operated radii were removed on 56th postoperative day and were evaluated for biomechanical properties and histopathological criteria.
Results: The results indicate that human PRP (as a xenogenic PRP) in treatment group significantly promote bone regeneration in critical size defects compared with control group (p
... Platelet rich plasma (PRP) is a highly concentrated form of autogenous platelets, providing a rich and readily obtainable source of a diverse group of growth factors (1). Its importance is related to the large variety of growth factors involved in healing that are physiologically contained in platelet α-granules (2). ...
INTRODUCTION: Despite the various methods described in producing platelet-rich plasma (PRP), it is well established that this biological product in its many preparations have been proven to enhance wound healing. However, very little have been known about the efficacy of these methods hence there is a lack of evidence in the superiority of one method over another. Thus, a study was conducted to compare these different protocols to determine
which produces the highest concentration of platelets. METHODS: Peripheral blood was obtained from 24 healthy volunteers. Four different protocols using similar 2 step centrifugation methods of preparing PRP were applied to an equal number of samples in this study. Platelet counts were performed on whole blood (without processing), PRP preparations and platelet-poor plasma (PPP). RESULTS: All protocols produced higher amounts of platelet concentrates in PRP preparations than plasma. However, centrifugation at 150g for 10 minutes followed by another at 450g at 10 minutes produces significantly higher amount of platelets concentration (p<0.05). CONCLUSION: Optimizing the protocols to produce PRP appears to be important in obtaining a maximal yield of platelet concentrate. Here the protocol described has shown to provide significant concentration yield over all others.
... Tais estudos descrevem diversas velocidades de centrifugação, locais de colheita de sangue, *Para cada parâmetro, valores seguidos de letras iguais na coluna não diferem entre si (p<0,05). volumes de sangue necessários, proporções do plasma considerados como PRP e substâncias para geliiicar o PRP (Aghaloo et al. 2002, Butterrield et al. 2005), o que propicia grande variação na concentração das plaquetas, podendo innluenciar nos diferentes efeitos biológicos in vivo (Anitua et al. 2006). Dentro os diversos tipos de anticoagulantes o citrato de sódio foi o escolhido por preservar a integridade da membrana das plaquetas, sendo o mais adequado no preparo do PRP (Marx 2000a, Trindade-Suedam et al. 2007 ). ...
Objective
To determine the effects of repeated placement of quantified lyophilised platelet-rich plasma (LPRP) on its soft and hard tissue components.
Methods
Lyophilised platelet-rich plasma was topically placed, and later injected, into fresh sockets using the third molar surgical model, randomised according to the split-mouth approach. The control site received placebo. The application of LPRP was done intraoperatively, one month and two months postoperatively. The measured endpoints included post-operative pain, swelling, trismus, pocket depth at mid-distal adjacent second molar, soft tissue healing, and bone formation (which was assessed radiographically). Fifteen healthy young adults, aged between 21 and 35 years, visiting the Oral and Maxillofacial Surgery Clinic at the University of Malaya were recruited for this study.
Results
There was no significant difference in post-operative pain, swelling size, trismus, and bone healing within their specific timelines during this study. However, the LPRP group showed significant reduction in pocket depth at the two-month post-operative period, suggesting that LPRP improves soft tissue healing.
Conclusion
Soft tissue healing, measured as the change of periodontal pocket depth, showed significant reduction, suggesting the benefit of LPRP for soft tissue healing. However, bone regeneration and reduction of post-operative sequelae showed no improvement even after quantification and repeated LPRP application.
Background
In clinical practice, autologous bone transplantation is usually used to treat large-scale bone defects. However, autologous bone can cause complications such as secondary injury to patients, the scarcity of autografts. In this study, the study of using super active platelet lysate (sPL) and allogeneic bone to treat the 15 mm long bone defect in right radius of New Zealand white rabbits, and provide an experimental basis for the next step of bone defect treatment.
Methods
The critical-size defect of New Zealand white rabbits was made and divided into three groups: autologous bone group, allogeneic bone group and sPL group. They were euthanized 1 month, 2 months and 3 months after the operation. perform imaging and histological observation on the repair of bone defect area.
Results
The results showed that there were varying degrees of new bone in the bone defect. CT data showed that the bone defect repair rate and new bone mass in each group increased month by month (P <0.05). Bone tissue (BV) and bone tissue to the total volume (BV/TV, %) in the sPL group> allogeneic bone group, autologous bone group > allogeneic bone group, with statistical significance (P <0.05). Compared with the allogeneic bone group, the sPL group can significantly promote the healing of bone defects, enhance the bone density after fracture healing. The repair effect after three months was similar to that of the autogenous bone group.
Conclusions
The use of allogeneic bone and sPL therapy may become part of a comprehensive strategy for tissue engineering to treat bone defects.
In aged individuals, osteopenia is a great concern for achieving solid spinal fusion. Spinal malunion could lead to various implant-related complications and reduce postoperative quality of life. This study aims to investigate the efficacy of collagen-binding bone morphogenetic protein-2 (CBD-BMP-2) on the treatment of lumbar inter-transverse defects and to explore whether platelet-rich plasma could help CBD-BMP-2 to achieve a better outcome in terms of osteogenesis in senile rats with osteopenia. In vitro experiment proved the angiogenic function of platelet-rich plasma and osteogenic effect of CBD-BMP-2. Rats were performed posterolateral lumbar inter-transverse fusion. Rats implanted with CBD-BMP-2 + platelet-rich plasma were assigned to Group A (n = 20), rats implanted with CBD-BMP-2 were assigned to Group B (n = 20), and those with platelet-rich plasma were assigned to Group C (n = 20). Four weeks after implantation, radiographic assessment, manual palpation, and histological evaluation were performed. In vivo experiments showed satisfactory therapeutic effect on lumbar inter-transverse fusion in both Groups A and B and better results of bone microarchitecture in Group A. Solid fusion rate was 77.8% in Group A, 66.7% in Group B, and 0% in Group C (P < 0.001). Our study indicated that CBD-BMP-2 could effectively facilitate the lumbar inter-transverse fusion in aged rats with osteopenia and platelet-rich plasma could help CBD-BMP-2 to enhance the bone healing of vertebral defects.
Developing minimal invasive strategies via injectable hydrogels for effective repairing of cartilage defects is highly desired. Injectable hydrogels, which can simultaneously embed cell and growth factors (GFs), serve as in situ formed scaffolds and could support an accelerated tissue regeneration process. The purpose of this study is to fabricate a composite injectable hydrogel, based on alginate (Alg)/polyvinyl alcohol (PVA) incorporating platelet rich plasma (PRP)‐encapsulated Alg sulfate (AlgS) microbeads, as a localized sustained release system of GFs, for the articular cartilage regeneration. The results show that synthesized AlgS microbeads support the sustained release of PRP GFs during 14 days, where preserve the bioactivity of them more than the free PRP. Rabbit adipose‐derived mesenchymal stem cells in contact with PRP‐loaded AlgS beads show more proliferation (2.7 folds) and have obviously higher deposition of collagen type ΙΙ and GAGs than free PRP treated ones. In addition, cells encapsulated into the hydrogel including PRP sustained release system show upregulated expression of collagen type ΙΙ (61 folds), Aggrecan (294 folds) and SOX9 (71.5 folds), as cartilage‐critical genes, compared to the direct treatment by PRP. To summarize, the developed hybrid Alg/PVA hydrogel embedding with PRP‐encapsulated AlgS microbeads is suggested as a potential in situ formed scaffold for cartilage regeneration.
Les implants endo-osseux représentent à l'heure actuelle une approche thérapeutique des plus intéressantes en dentisterie mais leur mise en place est souvent compromise par une quantité insuffisante d'os dans la zone où ils doivent être implantés. Dans de telles situations, il est nécessaire d'accroître chirurgicalement le volume osseux disponible avant la mise en place des implants. Ces dernières années, les avancées dans la connaissance du fonctionnement des facteurs de croissance ont poussé les chercheurs à leur trouver des applications cliniques en implantologie. Le but de notre étude est de déterminer si l'utilisation des facteurs de croissance dans les procédures d'augmentation osseuse permet d'améliorer la régénération osseuse et l?ostéointégration des implants dans l'os nouvellement formé. Après quelques rappels sur la cicatrisation osseuse et l'ostéointégration, notre travail s'intéresse aux différents facteurs de croissance impliqués dans la régénération osseuse. Puis, nous nous attardons sur deux applications cliniques des facteurs de croissance en implantologie : la rhBMP-2 et les concentrés plaquettaires. En nous basant sur les études animales et humaines portant sur ces deux applications, nous analysons leurs effets sur la régénération osseuse et l'ostéointégration des implants. Nous concluons sur l'avenir des facteurs de croissance en chirurgie implantaire, qui parait très prometteur, mais aussi sur la nécessité de réaliser des études plus poussées et sur un plus long terme avant d'envisager une utilisation clinique de routine de ces agents biologiques.
Traditional reconstruction of the head and neck and significantly evolved over the last 20 to 30 years with advances in microvascular surgery, biologic materials such as bone morphogenic protein, and dental implant predictability. Earlier and more definitive reconstruction can now be achieved with combining therapies, allowing patients immediate restoration of function and improved cosmetics. Antiresorptive medications, such as Denosumab and bisphosphonates, have complicated bony reconstruction treatments with altered biology and less-predictable results. Virtual surgical planning is a major advancement for reconstruction pretreatment planning and designing of intraoperative tools to expedite the operation and achieve more predictable results.
Successful dental and orthopaedic implant outcomes are determined by the degree of osseointegration. Over the last 60 years, endosseous implants have evolved to stimulate osteogenesis without the need for exogenous biologics like bone morphogenetic proteins. An understanding of the interaction between cells and how cells interact with the physical features characteristics of their environments have has led to the development ofse bioactive implants. Implant surfaces that mimic the inherent chemistry, topography, and hydrophilicity wettability of native bone have been shown to provide cells in the osteoblast lineage cells with the structural cues to promote tissue regeneration and net new bone formation. Studies show that attachment, proliferation, differentiation, and local factor production, and mechanical and biophysical regulatory factors are sensitive to these implant surface characteristics. This review focuses on how surface properties including chemistry, topography, and hydrophilicity modulate protein adsorption, cell behavior, biological reactions, and signaling pathways in peri-implant bone tissue allowing the development of true biomimetics that promote osseointegration by providing an environment suitable for osteogenesis.
It has been suggested that bone grafts combined with platelet rich plasma (PRP) present greater density than bone grafts without PRP after healing process. However, this result may depend on proportion PRP/autogenous bone (AB) graft used. Objective: The purpose of this study was to analyze radiographically the influence of the proportion PRP/particulate autogenous bone (AB) graft on bone healing in surgically created critical size defects (CSD) in rat calvaria. Material and method: 50 rats were divided into 5 groups: C, AB, AB/PRP-50,
AB/PRP-100 and AB/PRP-150. A 5 mm diameter CSD was created in the calvarium of each animal. In Group C the defect was filled by blood clot only. In Group AB the defect was filled with 0.01 mL of AB graft. In groups AB/ PRP-50, AB/PRP-100 and AB/PRP-150 the defects were filled with 0.01 mL of AB graft combined with 50, 100 and 150 µL of PRP, respectively. All animals were euthanized at 30 days post-operative. Standardized radiographic images of the rat calvaria were obtained using Digora System (Soredex, Finland). The images were evaluated by three examiners using scores that indicated the percentage of radiopacity of the defect. The obtained data were subjected to statistical analysis (Kruskal-Wallis test, p < 0.05). Result: Group C presented radiopacity significantly lower than groups AB, AB/PRP-50, AB/PRP-100 and AB/PRP-150. Group AB/PRP-50 showed radiopacity significantly greater than groups AB/PRP-100 and AB. Conclusion: It can be concluded that the proportion PRP/AB graft influences bone healing in CSD in rat calvaria.
Aims: Alveolar bone regeneration is frequently necessary for dental implant placement in maxillofacial surgery. Recent reports indicate that high levels of peptid growth factors presence in platelet rich plasma (PRP) may enhance wound healing and the formation of new bone when used in combination with bone grafts. To assess the effect of topical PRP concentrace on the bone regeneration, patients undergoing maxillofacial procedures were studied.
Method: Autologous platelet concentrate was obtained from PRP derived from 450ml blood. PRP was concentrated by centrifugation and adjusted to 1010 platelets per ml by the local department for transfusion medicine.
A prospetive controlled randomised study was designed two years ago. Included were patients with strong atrophy in endentulous maxilla who needed osteoplastic bone graft from the iliac crest for sinusfloor augmentation prior to implant placement.
The main parameter is the bone quality in the biopsy 4 months after augmentation messured as histomorphometry bone volume. As a side parameter we could registrate the radiological density in the CT made before implant insertion.
Platelet gel and bone preperatation was performed by using autologous materials only.
Results: Untill now we could include 48 patients. One patient showed localized resorption of the bone graft and one patient must be treated because of a sinusitis maxillaris. Histological evaluation of biopsy reveald numerous areas of osteoid and bone formation without evidence of inflammatory cell infiltrate. The bone volume reached from 40-70%. The final bone graft controlled by CT showed remarkably dense bone in sufficient quantity.
Conclusion: These findings suggest that topical use of autologous concentrated platelets may improve the process of bone regeneration.
The purpose of this study is to evaluation of effect on bone formation of PRP and Fibrin sealant in Bio-Oss grafts on rabbit cranial defect. Twelve rabbits were used as the animal model. Two equal 9mm diameter cranial bone defects were created in each rabbit and immediately grafted with Bio-Oss only, Bio-Oss + PRP, and Bio-Oss + Fibrin sealant. Rabbits were sacrificed at 4 and 8 weeks. New bone formation rate of grafted area were evaluated by histomorphometric analysis. No statistically significant difference of new bone formation rate was found between Bio-Oss only, Bio-Oss + PRP, and Bio-Oss + Fibrin sealant at 4 and 8 weeks (P>0.05). Adding PRP or Fibrin sealant to Bio-Oss did not show an increase of new bone formation in comparison to Bio-Oss grafting alone in cranial defect of rabbit.
Various controversial issues in third molar surgery are discussed in the light of the best available evidence; debates on prophylactic extractions, antibiotic prophylaxis, and control of short-term postoperative morbidities are among the issues presented. Important considerations in jaw augmentation such as donor site (endochondral vs. membranous), technicalities of harvest, and alternative procedures are viewed through the spectacle of current evidence. Also, the controversies involved in the treatment of mandibular condyles fractures are extensively discussed.
Orofacial rehabilitation after ablative surgery or trauma is one of the main objectives of oral and maxillofacial surgery. Many treatment strategies in this field thus fall into the realm of reconstructive surgery. A standard measure in the field of oral and maxillofacial reconstruction is the use of autogenous grafts for the replacement of tissue parts, which is associated with a significant increase in surgical effort and morbidity. The growing understanding of tissue healing and the achievements of biotechnology have raised hopes that defects of the jaw bones, articular cartilage, or oral mucosa can be repaired without the transfer of autogenous tissue and that custom made body parts can be cultivated from the patients own cells in the lab as a substitute for autogenous grafts.
Platelet concentrates in spine fusion gained increasing popularity among spine surgeons. They avoid morbidity of bone harvest and promise good union rates without additional device-related adverse events. Therefore, they seem to be a safe and effective alternative to common bone substitutes. This meta-analysis assesses the available evidence for union rate and overall complications with the use of platelet concentrates in spine fusion.
We conducted an online search for relevant controlled trials and extracted data on union rates, complications, and revision rates. These data were synthesized in a meta-analysis using fixed-effects odds ratios (OR). To assess covariates, meta-regression was performed as well.
Our search produced 166 results, ten of which were eligible for inclusion. These studies report on a total of 763 patients (328 experimental, 435 controls) with a mean age of 50.3 ± 7.5 years. Mean follow-up was 1.9 ± 0.0.4 years. With the use of platelet concentrates, union rate decreased significantly, OR 0.53 (95 % CI 0.35-0.79, p = 0.002), compared with the control group. There was no statistically significant difference in complication rates OR 1.34 (95 % CI 0.62-2.90, p = 0.46) or in revision rates OR 3.0 (95 % CI 0.90-10.00, p = 0.74). Meta-regression showed no statistically significant influence of randomization, Jadad score, or assessment of fusion.
The use of platelet concentrates in spine fusion shows significantly decreased union rates compared with the control group. However, complication and revision rates were not significantly increased. The current data do not recommend the use of platelet concentrate in spine fusion.
We describe the use of a rabbit maxillary sinus model, characterized by thin osseous tissue and low bone density, for the evaluation of surface-treated implants by histologically and histomorphometrically comparing the osseointegration patterns depending on the surface treatment methods. Twenty rabbits were randomly assigned to two groups of 10 animals, one receiving 5 × 3 mm customized implants (machined, MA or sandblasted and acid etched, SLA) placed in sinus and the other receiving implants placed in a tibia. Histological observation of the implant placed in sinus shows relatively more active new bone formation, characterized by trabecular bone pattern underneath the cortical bone in sinus as compared with that in tibia. Histomorphometric analysis in the rabbits receiving implants in a tibia, the NBIC (%) associated with the SLA surface implant was greater than that associated with the MA implant at 2 weeks (55.63 ± 8.65% vs. 47.87 ± 10.01%; P > 0.05) and at 4 weeks (61.76 ± 9.49% vs. 42.69 ± 10.97%; P < 0.05). Among rabbits receiving implants in a sinus, the NBIC (%) associated with the SLA surface implant was significantly greater than that associated with the MA surface implant both at 2 weeks (37.25 ± 7.27% vs. 20.98 ± 6.42%; P < 0.05) and at 4 weeks (48.82 ± 6.77% vs. 31.51 ± 9.14%; P < 0.05). As a result, we suggest that the maxillary sinus model is an appropriate animal model for assessing surface-treated implants and may be utilized for the evaluation of surface-treated implants in poor bone quality environment. Microsc. Res. Tech., 2015. © 2015 Wiley Periodicals, Inc.
© 2015 Wiley Periodicals, Inc.
Sinus augmentation is a common approach for patients with severe alveolar ridge atrophy but an ideal material to increase the bone volume for dental implantation is still needed. The present study evaluated the effect of a newly developed polymeric bone-filling powder (formed from acrylic acid and N-isopropylacrylamide, ANa) mixed with platelet-rich plasma (PRP) for bone generation in a rabbit model of sinus augmentation. A total of 12 New Zealand White rabbits were randomly divided into three groups based on filling material. All animals underwent a bilateral maxillary sinus augmentation. PRP was prepared using an automatic separation system to obtain a high platelet concentration. ANa powder was individually mixed with phosphate-buffered saline (PBS) or PRP for sinus floor elevation. The left maxillary sinus received the ANa/PBS filling, whereas the right maxillary sinus received a mixture of ANa/PRP gel. Equal volumes of filling material were inserted in each maxillary sinus. Thus, defects with no implantation served as controls. Animals were sacrificed at 4 and 12 weeks, and then all specimens were harvested for micro-computed tomography (micro-CT) and histological analysis. On micro-CT evaluation, ANa/PRP significantly increased the bone volume in maxillary sinus augmentation relative to the negative control and ANa/PBS after 12 weeks. New bone areas with osteocytes and osteon formation were found in all three groups at 12 weeks post-implantation. This study confirms that ANa mixed with PRP can effectively increase the bone volume in the sinus cavity. This benefit for sinus augmentation may increase the success of dental implantation because of the formation of a thin layer of alveolar bone.
We have shown that coculture of bone marrow microvascular endothelial cells with hematopoietic progenitor cells results in proliferation and differentiation of megakaryocytes. In these long-term cultures, bone marrow microvascular endothelial cell monolayers maintain their cellular integrity in the absence of exogenous endothelial growth factors. Because this interaction may involve paracrine secretion of cytokines, we evaluated megakaryocytic cells for secretion of cytokines, we evaluated megakaryocytic cells for secretion of vascular endothelial growth factor (VEGF). Megakaryocytes (CD41a+) were generated by ex vivo expansion of hematopoietic progenitor cells with kit-ligand and thrombopoietin for 10 days and further purified with immunomagnetic microbeads. Using reverse transcription-PCR, we showed that megakaryocytic cell lines (Dami, HEL) and purified megakaryocytes expressed mRNA of the three VEGF isoforms (121, 165, and 189 amino acids). Large quantities of VEGF (> 1 ng/10(6) cells/3 days) were detected in the supernatant of Dami cells, ex vivo-generated megakaryocytes, and CD41a+ cells isolated from bone marrow. The constitutive secretion of VEGF by CD41a+ cells was stimulated by growth factors of the megakaryocytic lineage (interleukin 3, thrombopoietin). Western blotting of heparin-Sepharose-enriched supernatant mainly detected the isoform VEGF165. In addition, immunohistochemistry showed intracytoplasmic VEGF in polyploid megakaryocytes. Thrombin stimulation of megakaryocytes and platelets resulted in rapid release of VEGF within 30 min. We conclude that human megakaryocytes produce and secrete VEGF in an inducible manner. Within the bone marrow microenvironment, VEGF secreted by megakaryocytes may contribute to the proliferation of endothelial cells. VEGF delivered to sites of vascular injury by activated platelets may initiate angiogenesis.
Retrospective data from sinus floor augmentation bone grafts were collected from 38 surgeons for 1007 sinus grafts that involved the placement of 2997 implants over a 10-year period, with the majority of the implants followed for 3 years or more postrestoration. There were 229 implant failures reported. Various root-form implants and grafting modalities were used. A consensus conference was organized to evaluate the data and reach a consensus on optimal treatment protocols. The complete database demonstrated a 90.0% success rate for implants placed in sinus grafts with at least 3 years of function. Differences in grafting materials, implant surfaces, and timing protocols were statistically analyzed. However, the database was so multivariate and multifactorial that it was difficult to draw definitive conclusions; these must await controlled prospective studies. The consensus conference therefore developed and voted on multiple consensus statements derived by committee review for bone graft materials, type of implants, timing for implant placement, failure analysis, radiographic analysis, indications/contraindications, prosthetics, and nomenclature. Several consensus statements were obtained, the most significant being that the sinus graft should now be considered a highly predictable and effective therapeutic modality.
This study compared two methods of preparing platelet-rich plasma (PRP) gel and the levels of PDGF and TGFbeta in each preparation.
Platelet-rich plasma gel was prepared by centrifugation and clotted using the ITA gelling agent (Natrex Technologies Inc, Greenville, NC) or by the addition of thrombin and calcium chloride. The levels of platelet-derived growth factor (PDGF) and transforming growth factor beta (TGFbeta) generated by clot formation were assayed by enzyme-linked immunoassay (ELISA).
Both methods of preparation yielded PRP gel in less than 30 minutes. However, the ITA preparation did not require thrombin to achieve adequate gel formation. The levels of PDGF and TGFbeta were similar regardless of which method was used for initiation of clot formation.
Use of ITA for gel preparation is equivalent to using calcium chloride and thrombin, without the need for special equipment and the risk of coagulopathy.
The present study was designed to compare recombinant human bone morphogenetic protein-2 (rhBMP-2) impregnated on an absorbable collagen sponge (ACS) with particulate cancellous bone and marrow (PCBM) harvested from the iliac crest in an animal model of maxillary sinus floor augmentation. Bilateral sinus floor augmentation procedures were performed in 30 adult Japanese white rabbits. rhBMP-2/ACS or PCBM was grafted to each maxillary sinus. Animals were sacrificed at 2, 4, or 8 weeks after grafting, and bone formation in response to each implant was evaluated histologically and histometrically. Histometric results compared by analysis of variance revealed no statistically significant difference in the bone volume at augmented areas between the two types of implant (P > 0.05). Histologic evaluation documented that the trabeculae with a lamellar structure were embedded in fatty marrow at 8 weeks in both implant sites. These results suggest that sinus floor augmentation with rhBMP-2/ACS or PCBM induces comparable histologic and histometric evidence of bone formation in rabbits.
Platelet-rich plasma is an autologous source of platelet-derived growth factor and transforming growth factor beta that is obtained by sequestering and concentrating platelets by gradient density centrifugation. This technique produced a concentration of human platelets of 338% and identified platelet-derived growth factor and transforming growth factor beta within them. Monoclonal antibody assessment of cancellous cellular marrow grafts demonstrated cells that were capable of responding to the growth factors by bearing cell membrane receptors. The additional amounts of these growth factors obtained by adding platelet-rich plasma to grafts evidenced a radiographic maturation rate 1.62 to 2.16 times that of grafts without platelet-rich plasma. As assessed by histomorphometry, there was also a greater bone density in grafts in which platelet-rich plasma was added (74.0% ± 11%) than in grafts in which platelet-rich plasma was not added (55.1% ± 8%; p = 0.005).
Platelets contain a vast number of biologically active molecules within cytoplasmic granules which are classified according to their respective distinct ultrastructures, densities and content. The α-granule is a unique secretory organelle in that it exhibits further compartmentalization and acquires its protein content via two distinct mechanisms: (1) biosynthesis predominantly at the megakaryocyte (MK) level (with some vestigial platelet synthesis) (e.g. platelet factor 4) and (2) endocytosis and pinocytosis at both the MK and circulating platelet levels (e.g. fibrinogen (Fg) and IgG). The currently known list of α-granular proteins continues to enlarge and includes many adhesive proteins (e.g. Fg, von Willebrand factor (vWf) and thrombospondin (TSP)), plasma proteins (e.g. IgG and albumin), cellular mitogens (e.g. platelet derived growth factor and TGFβ), coagulation factors (e.g. factor V) and protease inhibitors (e.g. α2-macroglobulin and α2-antiplasmin). More recently the inner lining of the α-granule unit membrane has been demonstrated to contain a number of physiologically important receptors including glycoprotein IIb/IIIa (αIIbβ3) and P-selectin. The α-granules originate from small precursor granules which can be observed budding from the trans-Golgi network within the platelet precursor cell, the MK. During MK maturation the α-granules become very prominent and are ultimately packaged into platelets during thrombopoiesis. The α-granular contents are destined for release during platelet activation at sites of vessel wall injury and thus play an important role in haemostasis, inflammation, ultimate wound repair and in the pathogenesis of atherosclerosis.
Using a vital microscopic method—the titanium chamber—it has been possible for the first time to dynamically follow the healing patterns in ortotopical cancellous and cortical bone grafts. Cancellous grafts healed by an initial strong osteogenetic phase without previous resorption of pre-existing bone trabeculae. Cortical grafts occasionally also healed primarily with osteogenesis, however rapidly followed by a dominant resorptive phase. A second and much stronger osteogenetic phase followed 60 days or more after grafting. Lamellated bone was as a rule preceded by woven bone of which two different types are described. Woven bone observed before grafting became lamellated afterwards which might be taken as an indication of survival of grafted woven bone. Numerous Howships lacunae, giving the bone a wavy appearance, were seen at resorption of bone trabeculae. In dense bone creeping substitution was observed. The cutter heads moved with an estimated rate of 30–40 microns a day. The resorption canals were later replaced by new bone formation. Vascular penetration rate in a cancellous graft was calculated to maximum 0.2-0.4 mm/day and in a cortical graft in pre-existing vascular canals to maximum 0.15-0.30 mm/day. A sufficient amount of vessels—about the same vascular density as before grafting—was necessary for bone remodelling to occur.
Platelet alpha-granules contain a factor that stimulates the proliferation of arterial smooth muscle cells and may play a role in atherogenesis. We have studied the role of arachidonic acid in mediating the release of the platelet-derived growth factor (PDGF) from human platelets. PDGF was assayed by stimulating of [(3)H]thymidine incorporation into DNA of mouse 3T3 cells. Platelet aggregation and the release of platelet factor 4,beta-thromboglobulin, and serotonin were also studied. A biphasic response pattern was observed when gel-filtered platelets were incubated with arachidonate over the concentration range 0.01-0.4 mM. At low arachidonate levels (approximately 0.025-0.1 mM), specific concentration-dependent aggregation and release of PDGF and of the other components were observed. This effect was not seen with any of five other fatty acids tested and was suppressed by indomethacin (25 muM). At higher arachidonate concentrations (approximately 0.15-0.35 mM), a concentration-dependent turn-off of both aggregation and release occurred. At these concentrations the platelets remained functional, and no release of lactate dehydrogenase was observed. A similar biphasic pattern of arachidonate-induced aggregation and release was observed with platelet-rich plasma, over a similar range of arachidonate to albumin mole ratios. These studies demonstrate that PDGF and other alpha-granule constituents can be released from platelets specifically by arachidonate via an indomethacin-sensitive pathway, most probably involving the platelet cyclooxygenase and conversion of arachidonate to prostaglandin metabolities. The mechanisms responsible for the turn-off of the specific arachidonate-mediated responses at higher arachidonate concentrations remain to be defined.
A Simplex is an empirical, geometric feedback strategy which progressively programs a series of experiments according to the results of the preceeding experiments. It leads to definition of conditions which maximize or minimize the result of experiments in two or more variables. When applied to study a laboratory method it dictates simultaneous variation of the conditions of an experiment, differing from the usual approach in which variables are altered sequentially and arbitrarily. A two variable Simplex (force and duration of centrifugation) has been applied to maximize platelet recovery in platelet rich plasma (PRP). The technique of Simplex is described. Maximal recovery of platelets in PRP was reached by centrifugation at 2160 ×g for 2.7 minutes.
To confirm the correctness of this result, platelet concentrates were prepared from PRP's separated by three different methods: 1) conditions determined by Simplex, 2) American National Red Cross recommended method (2820 ×g for two minutes), and 3) Canadian Red Cross recommended method (995 ×g for nine minutes). Mean recovery of 78 per cent was obtained by Simplex, significantly higher than 61 per cent with the American National Red Cross method (p > .005) and higher than 69 per cent with the Canadian Red Cross method. Simplex strategy is recommended as a simple, powerful technique for determining optimal experimental or laboratory conditions.
Units of whole blood were centrifuged for various periods of times and at various speeds to prepare platelet-rich plasma. It was found that several sets of centrifugation conditions resulted in an optimum yield of platelets and plasma. This optimum was approximately 8.3 x 10(10) platelets in 245 ml of plasma. When platelet-rich plasma was centrifuged, a maximum of approximately 95 per cent of the platelets could be recovered in the concentrate. Although this maximum was also achieved by several sets of centrifugation conditions, the most efficient method was 3,800 RPM (3731 x g) for four minutes at speed.
The CHRF-288-11 cell line has been previously shown to exhibit properties consistent with a megakaryocytic origin. The response of these cells to thrombin has now been investigated. Thrombin treatment of CHRF-288-11 cells results in both an increase in intracellular free calcium levels and secretion of mitogenic activity and beta-thromboglobulin. Cell viability is not affected. The mitogenic activity released from the cells is due primarily to the presence of basic fibroblast growth factor. Immunohistochemical data indicate a packaging of basic fibroblast growth factor into granular structures. Trypsin and phorbol 12-myristate 13-acetate also initiate release of mitogenic activity from this cell line, whereas under non-stirred conditions collagen and ADP do not. Through measurements of intracellular calcium levels it was determined that thrombin pretreatment of cells ablates a further response to thrombin, but does not block an increase in intracellular calcium levels due to trypsin. This suggests that these two agonists may act through different mechanisms. The thrombin-induced release reaction is inhibited almost completely by the reagents hirudin and dipyridamole, and only partially by indomethacin. These data indicate that the CHRF-288-11 cell line should provide an excellent model system in which to study the packaging of factors into granules which undergo regulated release.
A simple and inexpensive means of creating autologous fibrin glue is described that avoids the potential disadvantages of conventionally obtained material. This improvement may allow more widespread use of fibrin glue for operative bleeding.
Titanium implants, with an acid-etched surface, were screwed into holes 3 mm in diameter, about 1 cm apart, carefully prepared with an internally irrigated, surgical bur in the femurs of 3- to 6-month-old rabbits. During the first 3 days after surgery, fluorescent bone labels revealed extensive bone formation, particularly at the endosteal margin of the surgical defect, indicating preservation of a high degree of osteogenic capacity. A lattice of coarse, woven bone began encapsulating the implant within 3 days. By the end of 6 weeks, mature, lamellar bone filled voids at or near the implant surface and a rigid bone/implant interface was routinely achieved. Nonspecific, subperiosteal bony hypertrophy was noted within 6 weeks after implants were placed in young, growing animals (3 months old), but not in adults (6 months old). After 6 to 12 weeks of healing, a 100-gm load was applied for 4 to 8 weeks by stretching a stainless steel spring between the implants. All but one of twenty loaded implants remained rigid. Immediate loading of four pairs of implants resulted in spontaneous spiral-type ("torsional") fractures of the femur within 1 week. These results indicate that (1) relatively simple and inexpensive titanium implants develop a rigid osseous interface, (2) 6 weeks is an adequate healing period, prior to loading, to attain rigid stability and avoid spontaneous fracture, (3) continuously loaded implants remain stable within the bone, (4) bone formation is observed on periosteal surfaces subjected to concave flexure (compression), (5) cancellous-type bone orients perpendicularly between loaded implants, apparently corresponding to lines of stress, (6) new secondary osteons are propagated at or near the surface of loaded implants, (7) the remodeling (turnover) cycle for rabbit compact bone is about 6 weeks, and (8) endosseous implants have potential as a source of firm osseous anchorage for orthodontics and dentofacial orthopedics.
Using a vital microscopic method--the titanium chamber--it has been possible for the first time to dynamically follow the healing patterns in ortotopical cancellous and cortical bone grafts. Cancellous grafts healed by an initial strong osteogenetic phase without previous resorption of pre-existing bone trabeculae. Cortical grafts occasionally also healed primarily with osteogenesis, however rapidly followd by a dominant resorptive phase. A second and much stronger osteogenetic phase followed 60 days or more after grafting. Lamellated bone was as a rule preceded by woven bone of which two different types are described. Woven bone observed before grafting became lamellated afterwards which might be taken as an indication of survival of grafted woven bone. Numerous Howships lacunae, giving the bone a wavy appearance, were seen at resorption of bone trabeculae. In dense bone creeping substitution was observed. The cutter heads moved with an estimated rate of 30--40 microns a day. The resorption canals were later replaced by new bone formation. Vascular penetration rate in a cancellous graft was calculated to maximum 0.2--0.4 mm/day and in a cortical graft in pre-existing vascular canals to maximum 0.15--0.30 mm/day. A sufficient amount of vessels--about the same vascular density as before grafting--was necessary for bone remodelling to occur.
Using a vital microscopic method, it has been possible to follow the vascular changes and bone remodelling in the same bone graft from the time of transplantation till one year afterwards.
Grafts which received their first vessel early (5–9 days after grafting) contained vital bone and a vivid blood circulation one year after transplantation. Grafts which received their first vessel late (17-29 days after grafting) were only partly revascularized after one year and contained islands of dead bone.
Minimal surgical trauma toboth graft and the host bed is important for early revascularization of the graft, and, therefore, also contributes to a more complete incorporation of the graft.
A significant proportion of platelets is lost in the red blood cell mass and with the buffy coat during the preparation of platelet-rich plasma by differential centrifugation. It has been suggested that these lost platelets constitute a subpopulation of platelets that are young and highly effective in hemostasis. We compared the volume and density of these lost platelets with platelets from platelet-rich plasma, and measured the in vivo survival of platelets isolated with platelet-rich plasma (69.7% of the total platelets) and a total platelet population (97% of total platelets). Platelets from the total population had the same mean volume (7.62 μ 3) as platelets from platelet-rich plasma (7.60 μ 3). However, the mean volume of the subpopulation of lost platelets was slightly smaller than the mean volume of platelets from platelet-rich plasma (p < 0.005). No differences in relative density were found in lost platelets when compared with platelets from platelet-rich plasma as measured by their capacity to sediment through a fixed-density arabinogalactan medium. In four donors, the mean survival times of platelets from platelet-rich plasma and total platelet population did not differ significantly. We conclude that the platelets present in platelet-rich plasma are representative of the whole platelet population and that blood banks do not sacrifice a subset of large, heavy, young platelets in preparing platelet-rich plasma.
We evaluated in vitro platelet function of platelet concentrates stored at 22 C for 5 days prepared either by the conventional pelleting procedure or platelet concentrates prepared from buffy coats by utilizing a novel bucket designed to support a suspended bag. For platelet concentrates from buffy coat, whole blood was centrifuged at 3,000 x g for 13 min, with all but 30cc of the cell poor plasma transferred to a satellite bag, followed by a second centrifugation at 170 x g for 5 min utilizing our novel centrifugation device. For pelleted platelets, whole blood was centrifuged at 2,000 x g for 3 min, platelet rich plasma removed, centrifuged, and the pellet resuspended in plasma. Leukocyte contamination in buffy coat platelet concentrates was reduced by 95% (p < 0.001) in comparison to pelleted platelets. Further, platelets from buffy coat platelet concentrates demonstrated significantly enhanced ADP-induced aggregation, increased recovery from hypotonic shock, higher morphology scores, and reduced GMP-140 expression in comparison to pelleted preparations. No differences in O2 consumption, CO2 production, pH and total ATP were observed between the two types of preparations at day 5 of storage. Our results indicate that platelet concentrates from buffy coat, prepared by a suspended storage bag centrifugation technique, are superior with respect to in vitro platelet function when compared to pelleted platelets.
The platelet content of platelet-derived growth factor (PDGF), a mitogen stored in the alpha-granules, was studied during preparation and storage of platelet concentrates (PC) and compared to the growth-promoting activity of platelets, beta-thromboglobulin (beta-TG) and lactate dehydrogenase (LD). We compared PC prepared from platelet-rich plasma (PRP-PC; n = 10) and from buffy coat. Two different pre-preparation storage periods of the buffy coat were used: 4 h (BC-PC:4h; n = 10) and 24 h (BC-PC:24h; n = 5). The platelet content of PDGF and beta-TG was measured by a RIA technique and the growth-promoting activity by incorporation of 3H-thymidine in stimulated fibroblasts. The platelet content of PDGF, beta-TG and the growth-promoting activity of the platelets decreased in a similar way during preparation and storage of PRP-PC (31 +/- 2, 35 +/- 2 and 33 +/- 7%, respectively, at day 5 of storage; mean +/- SEM). The release of LD was minor (3.9 +/- 0.5% at day 5). At day 1 of storage the platelet content of PDGF was significantly better preserved in BC-PC:4h than in BD-PC:24h (88 +/- 2 and 81 +/- 3%, respectively; p = 0.03). Comparing BC-PC:4h and PRP-PC we found a significantly better preservation of PDGF in BC-PC:4h until day 3 of storage (80 +/- 2 and 75 +/- 1%, respectively at day 3; p = 0.046). In conclusion the preparation of PC according to the PRP method initially induces a higher loss of PDGF, and hence of the growth-promoting activity, than the BC method.
Occlusion of the maxillary ostium is considered to be a key factor in the pathogenesis of maxillary sinusitis. In this study, the authors determined the effect of ostial occlusion on pressure in the rabbit maxillary sinus which, like most humans, has only one ostium. We compared pressures in the normal and occluded maxillary sinus and the nasal cavity during spontaneous breathing in anesthetized adult animals. Serial pressure measurements were obtained from sinuses with patent ostia in nasal-breathing rabbits and with occluded ostia in both nasal-breathing and tracheotomized animals.
Sinuses with patent ostia showed pressure curves synchronous with the respiratory cycle. Inspiratory and expiratory pressures in the nasal cavity and the sinus were isobaric. Sinuses with occluded ostia initially developed a positive pressure followed by a negative pressure that reached a subatmospheric plateau of-28.2 ± 7.3 mm H2O (mean ± standard deviation [SD]) within 20 to 50 minutes.
This is the first quantitative study of sinus pressures using the rabbit as an animal model. The findings may contribute to a better understanding of the role of ostial occlusion in the pathogenesis of maxillary sinusitis in humans.
Platelets contain a vast number of biologically active molecules within cytoplasmic granules which are classified according to their respective distinct ultrastructures, densities and content. The alpha-granule is a unique secretory organelle in that it exhibits further compartmentalization and acquires its protein content via two distinct mechanisms: (1) biosynthesis predominantly at the megakaryocyte (MK) level (with some vestigial platelet synthesis) (e.g. platelet factor 4) and (2) endocytosis and pinocytosis at both the MK and circulating platelet levels (e.g. fibrinogen (Fg) and IgG). The currently known list of alpha-granular proteins continues to enlarge and includes many adhesive proteins (e.g. Fg, von Willebrand factor (vWf) and thrombospodin (TSP)), plasma proteins (e.g. IgG and albumin), cellular mitogens (e.g. platelet derived growth factor and TGF beta), coagulation factors (e.g. factor V) and protease inhibitors (e.g. alpha 2-macroglobulin and alpha 2-antiplasmin). More recently the inner lining of the alpha-granule unit membrane has been demonstrated to contain a number of physiologically important receptors including glycoprotein IIb/IIIa (alpha IIb beta 3) and P-selectin. The alpha-granules originate from small precursor granules which can be observed budding from the trans-Golgi network within the platelet precursor cell the MK. During MK maturation the alpha-granules become very prominent and are ultimately packaged into platelets during thrombopoiesis. The alpha-granular contents are destined for release during platelet activation at sites of vessel wall injury and thus play an important role in haemostasis, inflammation, ultimate wound repair and in the pathogenesis of atherosclerosis.
We performed a simple, undisplaced, incomplete osteotomy of the distal medial condyle of mature New Zealand White rabbits and permitted healing without fixation for 4 weeks. During the recovery period, the rabbits received the bone label calcein in their drinking water. From ground stained and unstained sections, we determined histomorphometric parameters in five zones: osteotomy gap, juxtaosteotomy, lateral condyle, metaphysis, and diaphysis. At 4 weeks, newly formed cancellous bone had obliterated the osteotomy gap. Osteotomy also stimulated new bone formation in cancellous bone of the medial condyle around the osteotomy. At that site, we found a fivefold increase in new bone without a change in bone volume (BV). Stimulation of bone formation was not observed in cancellous bone of the lateral condyle that had not been operated on or in cortical bone of the metaphysis or diaphysis. The maintenance of BV, despite increased new bone formation in the osteotomized medial femoral condyle, was probably due to a local acceleration of bone remodeling.
The preparation and use of platelet gel, an autologous formulation of fibrin glue, are described. The unique features of this biologic sealant are that it is derived from autologous blood collected in the immediate preoperative period by the anesthesiologist, it contains a high concentration of platelets, and it can be used in patients who are not candidates for blood bank donation. Platelet gel has been used successfully in the area of reconstructive oral and maxillofacial surgery in conjunction with ablative surgery of the maxillofacial region, mandibular reconstruction, surgical repair of alveolar clefts and associated oral-antral/ oral-nasal fistulas, and adjunctive procedures related to the placement of osseointegrated implants.
Platelet-rich plasma is an autologous source of platelet-derived growth factor and transforming growth factor beta that is obtained by sequestering and concentrating platelets by gradient density centrifugation. This technique produced a concentration of human platelets of 338% and identified platelet-derived growth factor and transforming growth factor beta within them. Monoclonal antibody assessment of cancellous cellular marrow grafts demonstrated cells that were capable of responding to the growth factors by bearing cell membrane receptors. The additional amounts of these growth factors obtained by adding platelet-rich plasma to grafts evidenced a radiographic maturation rate 1.62 to 2.16 times that of grafts without platelet-rich plasma. As assessed by histomorphometry, there was also a greater bone density in grafts in which platelet-rich plasma was added (74.0% +/- 11%) than in grafts in which platelet-rich plasma was not added (55.1% +/- 8%; p = 0.005).
Since 1990, platelet concentrates prepared by soft centrifugation of buffy-coat pools diluted with a glucose-free, commercially available crystalloid solution (BC-PC) are the first choice product for all platelet recipients in our institution. Numerous in vitro and in vivo observations from our own and other laboratories indicate that BC-PC compare favorably to PC prepared from platelet-rich plasma (PRP). In the present in vitro study we evaluated traditional and bottom-and-top bags and modified centrifugation conditions with the aim of increasing in vitro platelet yield in BC-PC. This was 14-18% higher compared with our previous protocol when prolonged centrifugation and bottom-and-top bags were used. In addition, we evaluated post-transfusion platelet count increments in 42 unselected adult hematological patients routinely transfused with 703 1-5 day-old BC-PC pools. Transfusion data were managed with PLATELET, an MS-DOS compatible program which includes automated calculation of transfusion efficacy and periodic patient reports. Mean pre-, 1 h and 24 h post-transfusion platelet counts were 16, 38 and 28x10 9/L, respectively. Mean 1 h and 24 h post-transfusion platelet count increments, expressed as percentage of expected, were 40 and 24%, respectively. These data were similar to those obtained previously in 189 unselected hematological patients given 2432 PRP-PC transfusions (mean 1 h post-transfusion increment 46% of expected). The present in vitro study confirms that similar platelet yields can be obtained with the BC and PRP methods. In vivo findings show that also in routine conditions post-transfusion increments of PRP-PC and BC-PC are similar.(ABSTRACT TRUNCATED AT 250 WORDS)
This study involving rabbits was undertaken to establish an experimental model for the sinus lift procedure and to clarify the repair of autogenous grafted bone in the maxillary sinus.
A corticocancellous bone block was grafted into the maxillary sinus of each of 18 rabbits. Each animal was killed at 2, 4, or 8 weeks after grafting and then histologically evaluated.
At 2 weeks, new bone formation was observed. There was no inflammation of the antral membrane. At 4 weeks, lamellar structures were observed in newly formed bone. At 8 weeks, newly formed cortical bone was observed under the elevated membrane and the medullary cavity was almost completely occupied by fat cells.
There were no histologic complications after the sinus lift procedure. Histologic results indicated that newly continuous cortical bone was formed along the elevated membrane at 8 weeks. This animal model could be useful as a sinus lift model.
This article presents preliminary clinical evidence of the beneficial effect of the use of plasma rich in growth factors of autologous origin. The plasma is obtained from the individual patient by plasmapheresis. The macroscopic and microscopic results obtained with bone regeneration using this technique, which uses no membrane or barrier, can be observed. The incorporation of these concepts can introduce several advantages, including the enhancement and acceleration of bone regeneration and more rapid and predictable soft tissue healing.
The effect on platelets of two standard methods of platelet concentrate (PC) preparation was studied by flow cytometry. The findings were correlated with those obtained in an experimental in vitro perfusion model.
PCs were prepared from whole blood by the platelet-rich plasma (PRP) or buffy coat (BC) method and placed on a flatbed platelet agitator at 22 degrees C for up to 5 days. Platelet glycoproteins (GP)lbalpha, GPIIb/IIIa, and GPIV, p-selectin and lysosomal integral membrane protein, and the binding of von Willebrand factor, fibrinogen, fibronectin, and coagulation factor Va were measured with the corresponding specific conjugated antibodies. Perfusions were carried out in an annular chamber with citrated blood depleted of platelets and white cells by filtration, to which samples from PCs were added.
PRP-PC production provoked intense platelet activation. In contrast, in BC-derived PCs, platelet activation was milder, and only a significant increase in bound fibrinogen was seen. After 1 day of storage, differences between the methods that had been observed immediately after separation had almost disappeared. During the remaining storage period, increases in activation-dependent antigens and in procoagulant activity were measured. Of the studied platelet GPs, only GPIIIb/ IIIa decreased by 25 percent in PRP-PCs. Differences in covered surface were not significant in perfusion studies performed on Day 0 and after 5 days of storage in PRP-PCs (26.8 +/- 6.9 vs. 20.5 +/- 5.8) or BC-PCs (23.8 +/- 11 vs. 24.8 +/- 10.2).
Platelet activation occurred during the separation and storage of PCs prepared by both methods, and it was higher in PRP-PCs only in samples obtained immediately after preparation. Despite these changes, platelet adhesive and cohesive functions were similar in both types of PCs and remained basically unchanged after storage.
A method to produce platelet-rich plasma and platelet concentrate using a double centrifuge technique in combination with the fibrin adhesive Tisseel is described. This technique constitutes the basic mixture for augmenting and improving an inadequate bone site. Also described is a procedure by which autologous bone or bone substitute is added to this mixture to increase the volume of grafting material. Platelet concentrates cause growth factors to be delivered to graft sites in an intense form, while Tisseel serves as a standardized, pharmaceutically manufactured fibrin adhesive.
To evaluate changes in volume and structure of bone after autogenous iliac crest bone grafting to the maxilla. To discover the predictive value of computed tomographic (CT) measurements of bone density and study their correlation with the results of histomorphometric analyses of bone structure.
In 25 patients with atrophic maxillae (mean age 47 years, range 15-71), who had onlay bone grafting and sinus floor augmentation with autogenous iliac crest bone, a CT analysis was carried out immediately before and after grafting, and 5 months (range 4-6) later, at the time of endosseous implantation. On both occasions, bone biopsy specimens were taken. HISTOLOGY OF BONE: After preparing and digitizing semithin sections, histomorphometry (NH-Image) was done to establish the ratio of trabeculae to medullary cavity. CT ANALYSIS: The available transverse and vertical bone and the bone density of natural and augmented bone were analyzed using the Simplant Program and the CT data. As reference, the bone density of the first cervical vertebra was used. By regression analysis, the correlation of CT bone density and histological bone structure was investigated.
After a median healing period of 4.5 months, no significant changes were found in bone volume compared with the measurements made immediately after grafting. The changes in density in the cancellous portion of the grafted bone showed no correlation (correlation coefficient: +0.16) with the results of histomorphometric analysis of bone structure.
The predictive value of measurement of bone density to evaluate bone structure on the basis of the D1-D4 classification needs to be reconsidered. The most favourable time for secondary implantation is 4-6 months after iliac crest bone grafting.
This study was undertaken to establish an experimental model for maxillary sinus augmentation in rabbits and to clarify the bone response to the occluded nasal ostium. In rabbits without ostial occlusion, the elevation of the sinus mucosa resulted in formation of a subantral hollow space filled with blood clots and granulation tissue 1 week after operation. The newly formed bone filled in the space had a central granulation tissue. The space was almost completely replaced by a normal sinus airspace after 3 weeks. In rabbits with ostial occlusion, a fully formed bone mass was seen after 3 weeks. The mass had both mature trabeculae and peripheral cortical bone containing no sinus airspace after 6 weeks. This animal model for maxillary sinus augmentation may improve our understanding of the bone formation procedure in humans and delineate how sinus air pressure caused by the occluded nasal ostium affects the quantity and fate of newly formed bone.
The purpose was to evaluate the effect of platelet-rich plasma (PRP) on bone healing.
Fifteen rabbits were included in this randomized, blinded, prospective pilot study. Four equal 8 mm diameter cranial bone defects were created and immediately grafted with autogenous bone, PRP alone, autogenous bone and PRP, and no treatment as a control. The defects were evaluated by digital subtraction radiography with step-wedge calibration, histology, and histomorphometric analysis performed at 1, 2, and 4 months.
The results showed a significant increase in histomorphometric bone area and radiographic bone density in both bone and bone and PRP samples as compared with the control and PRP alone. No significant increase in bone formation was seen with the addition of PRP to autogenous bone. No significant difference in bone formation was seen between defects treated with PRP alone and control sites.
No significant improvement, radiographically or histomorphometrically, was seen with the addition of PRP in bone formation in noncritical sized defects in the rabbit cranial model. However, bone and bone and PRP showed a histomorphometric tendency toward increased bone formation at 1, 2, and 4 months.
Role of thymidine phosphorylase activity in the angiogenic effect of PDEGF/ thymidine phosphorylase
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Mivadera KT, Dohmae N, Takio K, et al: Role of thymidine phosphorylase activity in the angiogenic effect of PDEGF/ thymidine phosphorylase. Cancer Res 55:1687, 1995
Color atlas of hematology
- Kracke
Kracke R: Color atlas of hematology, in Kracke R (ed): Color Atlas of Hematology (ed 1). Philadelphia, PA, Lippincott, 1947, pp 43-57
Mechanisms of action of skeletal growth factors in osteoblasts
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Stein GS, Owen TA, van Wijnen AJ, et al: Mechanisms of action of skeletal growth factors in osteoblasts, in Canalis E (ed): Skeletal Growth Factors (ed 1). Philadelphia, PA, Lippincott Williams & Wilkins, 2000, pp 52-54
Constitutive production and thrombin-induced release of VEGF by human megakaryoctes and platelets
- Mohle
Mohle RD, Green D, Moore MA, et al: Constitutive production and thrombin-induced release of VEGF by human megakaryoctes and platelets. Proc Natl Acad Sci U S A 94:663, 1997
Trichrome stainings and their preliminary technique
- Masson
Masson P: Trichrome stainings and their preliminary tech-nique. J Tech Meth 12:75, 1929
Platelet concentrates from buffy coats
- Rebulla
Response of human megakaryocytic cell line to thrombin
- Jones
Mechanisms of action of skeletal growth factors in osteoblasts
- Stein
Maxillary sinus augmentation model in rabbits
- Asai
Maxillary sinus floor augmentation in rabbits
- Wada
Reference values in experimental animals and humans
- Mitruka
Healing of cancellous bone osteotomy in rabbits-Part I
- Bogoch
Release of PDGF from human platelets by arachidonic acid
- Linder