Radiographic and histomorphometric analysis of bone healing using autogenous graft associated with platelet-rich plasma obtained by 2 different methods

Healing of particulate allografts mixed with platelet concentrates in ridge preservation and sinus lift: a prospective histomorphometric study

The objective of the present study was to evaluate the bone quality of sinus and alveolar grafts following filling with particulate allogenous bone (DFDBA 300-500μm) and platelet concentrate (platelet-rich fibrin, PRF). A prospective interventional clinical study was carried out. A total of 40 bone cores, 2mm in diameter, were taken from 21 patients: 22 from grafted alveoli, 7 from grafted sinus sites, and 11 from native bone used as a control. Fixed, paraffin-embedded samples were subjected to histological staining with hematoxylin-eosin and Masson's trichrome. Bone maturity of the samples was evaluated by two independent operators using histomorphometric analysis. There existed a greater proportion of lamellar neoformed bone than woven neoformed bone as the healing time increased. Moreover, there was also an increasing proportion of newly formed bone in the grafted sockets as a function of healing time (average: 41.22% ≤ 5 months, 55.89% ˃ 5 months). Resorption of DFDBA particles also appears to be correlated with healing time in the grafted socket (average: 15.43 ≤ 5 months, 13.72% ˃ 5 months). In conclusion, performing sinus lift and alveolar socket preservation techniques using DFDBA and PRF results in high quality, mature bone tissue according to histological criteria.

Maxillary sinus lift response to platelet-rich plasma associated with autogenous bone, ceramic biphasic HA/β-TCP (70:30), or deproteinized bovine bone

BACKGROUND

This study evaluated the long-term effects of platelet-rich plasma (PRP) on bone formation and regeneration when associated with autogenous bone graft (AB), porous biphasic calcium phosphate (pBCP), or deproteinized bovine bone (DBB) in maxillary sinus augmentation (MSA) of rabbit.

METHODS

In 54 rabbits, bilateral MSA procedure was performed and randomly one sinus was filled with 200 mm³ material plus blood clot (AB/clot, DBB/clot, and pBCP/clot) and other with the same graft plus PRP (AB/PRP, DBB/PRP, and pBCP/PRP). After 30, 60, and 180 days, microtomographic were performed to analyze the three-dimensional MSA volume and histomorphometric analyses for the percentage of bone and soft tissues ingrowth. Data were compared by two-way ANOVA and the means were compared by the Tukey test, at p < 0.05.

RESULTS

The percentage of pBCP and DBB were nearly unchanged throughout the whole period and bone formation occurred in the spaces between particles. The MSA volume filled with DBB and pBCP agglutinated with clot and PRP maintained constant during all experimental periods (147.2 mm³ and 154.9 mm³, respectively, p = 0.7377), and no significant changes in the new formatted bone and soft tissue were observed between treatments. In AB/clot and AB/PRP, the MSA volume was similar at 30 days (140.3 mm³ and 137.9 mm³, respectively), but a higher and gradual reduction was observed until 180 days. In the AB/PRP, this reduction was significantly higher (44.2%) than AB/clot (22.5%) (p = 0.01792). Histologically, the addition of PRP to AB accelerated the new bone formation/remodeling maintaining the percentage of new bone similar to AB/clot during all experimental volume (p = 0.6406), while the AB particles showed a higher resorption in AB/PRP than AB/clot until 60 days (mean of 7.8% and 15.1%, respectively, p = 0.0396).

CONCLUSION

The association of PRP with the autogenous graft accelerates the process of bone formation/remodeling in MSA, but not had influence on the pBCP and DBB groups.

Plasma rich in growth factors (PRGF) in intraoral bone grafting procedures: A systematic review

PURPOSE

This systematic review aimed at assessing the effects of PRGF in new bone formation, soft tissue healing and post-operative pain and swelling in sites that underwent ridge preservation, ridge augmentation and maxillary sinus augmentation procedures.

MATERIALS AND METHODS

A comprehensive literature search employing seven databases was conducted by two independent reviewers. Only randomized and non-randomized controlled clinical trials using PRGF alone or in combination with bone grafting materials were selected.

RESULTS

Overall, 919 studies were identified, of which a total of 8 articles were included in the qualitative analysis. Two of the selected studies reported on ridge preservation, one on ridge augmentation and five on maxillary sinus augmentation. Positive results were recorded for soft tissue healing and post-operative pain and swelling following these procedures. However, outcomes of PRGF on new bone formation post extraction and on maxillary sinus augmentation when combined with other biomaterials were conflicting. Meta-analysis could not be conducted for any variables due to the heterogeneity of selected studies.

CONCLUSION

Limited evidence exists on the effects of PRGF in different intraoral bone grafting procedures, with some benefit reported on soft tissue healing and post-operative symptomatology. As this platelet concentrate is commonly used in clinical practice, further research is needed to fully assess its clinical indications and effectiveness.

Comparative (Quantitative and Qualitative) Analysis of Three Different Reagents for Preparation of Platelet-Rich Plasma for Hair Rejuvenation

Objective:

The aim of this study was to compare the quantity and quality of platelets in platelet-rich plasma (PRP) samples prepared using three different reagents, namely, ethylenediaminetetraacetic acid (EDTA), sodium citrate, and acid citrate dextrose-A (ACD-A) solution.

Materials and Methods:

A prospective study was carried out in which all the 50 patients who attended the outpatient department for hair rejuvenation were enrolled for the study. All the patients had a history of hair fall with diffuse thinning of hair, Norwood Grades 2 and 3. Patients with complete hair loss were not included in the study. No specific randomization was carried out. All the patients were explained about the procedure and the use of vials containing the aforementioned three reagents. Then, 40mL blood was taken from each patient. Both quantitative and qualitative analyses of platelets were carried out on PRP samples. Quantitative analysis was done by using an automatic cell counter and cross-checking manually. Qualitative analysis was carried out by preparing smears from each of the three samples from each vial. All the patients were followed up at 4 weekly intervals for a duration of 6 months and then at the end of 1 year. All the patients received six sessions of PRP.

Results:

All the data were subjected to statistical analysis using Student’s t-test, and P value of <0.001 was obtained in samples from ACD-A vials, which was statistically significant. In all the 50 patients, the samples collected in vials containing ACD-A yielded the maximum quantitative count and the best morphology of platelets under smear examination.

Conclusion:

Within the limits of this study, we would like to conclude that ACD-A vials should be used for collecting and processing blood for PRP preparation to obtain best results in hair rejuvenation.

Implant osseointegration in irradiated bone: an experimental study

BACKGROUND AND OBJECTIVES

The aim of this study was to evaluate the effect of radiotherapy on the osseointegration of dental implants in the tibia and the action of platelet-rich plasma (PRP) as an adjuvant therapy.

MATERIAL AND METHODS

A total of 18 rabbits received two implants in each tibial epiphysis, totalizing 72 implants. The control group (group I) was composed by six rabbits and did not receive radiotherapy. The test groups (II and III) received a single dose of 1727 cGy. Group II was composed by six irradiated animals and group III by six animals that received irradiation and PRP during implant placement. The implant success rate, the bone-implant contact (BIC), and the bone volume were analyzed.

RESULTS

There was no osseointegration in four of the implants, three in group II and one in group III. Total BIC was significantly higher in group I, when compared to the other groups. There was a significant difference of osteoid BIC only between irradiated animals (group II, 8.5%; group III, 4.7%; p = 0.001). On the other hand, the mineralized BIC was significantly higher in group I. Furthermore, group II had a lower mineralized BIC than group III (p = 0.002). Bone volume was higher in the control group (41.3%), followed by group III (33.4%) and II (25.1%), with differences between groups I and II (p = 0.001) and groups II and III (p = 0.022).

CONCLUSIONS

The present study showed that both the bone volume and BIC were higher in the control group. However, the failure rates of the implants were low in both irradiated groups. The PRP was a positive adjuvant in the osseointegration process.

The healing effect of platelet-rich plasma on xenograft in peri-implant bone defects in rabbits

Background

The association of biomaterial combined with repair factor-like platelet-rich plasma (PRP) has prospective values. Bovine-derived xenograft has been identified as an osteoconductive and biocompatible grafting material that provides osseointegration ability. PRP has become a valuable adjunctive agent to promote healing in a lot of dental and oral surgery procedures. However, there are controversies with respect to the regenerative capacity of PRP and the real benefits of its use in bone grafts. The purpose of this study was to assess the influence of PRP combined with xenograft for the repair of peri-implant bone defects.

Methods

Twelve rabbits were used in this study, and the experimental surgery with implant installation was performed simultaneously. Autologous PRP was prepared before the surgical procedure. An intrabony defect (7.0 mm in diameter and 3.0 mm deep) was created in the tibia of each rabbit; then, 24 titanium dental implants (3.0 mm in diameter and 8.5 mm long) were inserted into these osteotomy sites. Thus, a standardized gap (4.0 mm) was established between the surrounding bony walls and the implant surface. The gaps were treated with either xenograft alone (control group) or xenograft combined with PRP (experimental group). After healing for 1, 2, 3, 4, 5, and 6 weeks, the rabbits were sacrificed with an overdose of KCl solution. Two rabbits were killed at each time, and the samples including dental implants and surrounding bone were collected and processed for histological analysis.

Results

More newly formed bone and a better bone healing process were observed in control group. The histomorphometric analysis revealed that the mean percentage of bone-to-implant contact in the control group was significantly higher than that of the experimental group (25.23 vs. 8.16 %; P < 0.05, independent-simple t test, analysis of variance [ANOVA]).

Conclusions

The results indicate that in the addition of PRP to bovine-derived xenograft in the repair of bone defects around the implant, PRP may delay peri-implant bone healing.

Cytokine, chemokine, and growth factor profile of platelet-rich plasma

During wound healing, biologically active molecules are released from platelets. The rationale of using platelet-rich plasma (PRP) relies on the concentration of bioactive molecules and subsequent delivery to healing sites. These bioactive molecules have been seldom simultaneously quantified within the same PRP preparation. In the present study, the flexible Bio-Plex system was employed to assess the concentration of a large range of cytokines, chemokines, and growth factors in 16 healthy volunteers so as to determine whether significant baseline differences may be found. Besides IL-1b, IL-1ra, IL-4, IL-6, IL-8, IL-12, IL-13, IL-17, INF-γ, TNF-α, MCP-1, MIP-1a, RANTES, bFGF, PDGF, and VEGF that were already quantified elsewhere, the authors reported also on the presence of IL-2, IL-5, IL-7, IL-9, IL-10, IL-15 G-CSF, GM-CSF, Eotaxin, CXCL10 chemokine (IP-10), and MIP 1b. Among the most interesting results, it is convenient to mention the high concentrations of the HIV-suppressive and inflammatory cytokine RANTES and a statistically significant difference between males and females in the content of PDGF-BB. These data are consistent with previous reports pointing out that gender, diet, and test system affect the results of platelet function in healthy subjects, but seem contradictory when compared to other quantification assays in serum and plasma. The inconsistencies affecting the experimental results found in literature, along with the variability found in the content of bioactive molecules, urge further research, hopefully in form of randomized controlled clinical trials, in order to find definitive evidence of the efficacy of PRP treatment in various pathologic and regenerative conditions.

New and emerging strategies in platelet-rich plasma application in musculoskeletal regenerative procedures: general overview on still open questions and outlook

Despite its pervasive use, the clinical efficacy of platelet-rich plasma (PRP) therapy and the different mechanisms of action have yet to be established. This overview of the literature is focused on the role of PRP in bone, tendon, cartilage, and ligament tissue regeneration considering basic science literature deriving from in vitro and in vivo studies. Although this work provides evidence that numerous preclinical studies published within the last 10 years showed promising results concerning the application of PRP, many key questions remain unanswered and controversial results have arisen. Additional preclinical studies are needed to define the dosing, timing, and frequency of PRP injections, different techniques for delivery and location of delivery, optimal physiologic conditions for injections, and the concomitant use of recombinant proteins, cytokines, additional growth factors, biological scaffolds, and stems cells to develop optimal treatment protocols that can effectively treat various musculoskeletal conditions.

Effect of autologous platelet-rich plasma on bone regeneration in mandibular fractures

OBJECTIVES

The aim of this study was to assess the effect of autologous platelet-rich plasma (PRP) on bone regeneration in mandibular fractures via a cone beam computed tomography (CBCT).

PATIENTS AND METHODS

Twenty-four patients having parasymphyseal fractures participated in this study. They were randomly divided into two equal groups. Group A was treated by two titanium miniplates and screws plus local application of activated PRP along the fracture line, whereas group B was treated by the same bone plates and screws without application of PRP. The patients were recalled at 1 week, 3 and 6 months after surgery for clinical assessment and measuring the bone density via CBCT at a region of interest (ROI) including the fracture line.

RESULTS

The mean values of the bone density measurements, in both groups, were higher at 3 and 6 months than 1 week after surgery. At 1 week after surgery, the values were 542 ± 93 HU and 515 ± 81 HU in group A and B, respectively. In group A, the mean value of bone density measurements was 728 ± 58 HU (range 620-796 HU) at 3 months after surgery and it was 1024 ± 188 HU (range 825-1490 HU) 6 months later. While in group B, the mean values of the bone density measurements at the ROI were 600 ± 78 HU (range 520-790 HU) and 756 ± 53 HU (range 710-890 HU) at 3 and 6 months after surgery, respectively. The increase in the bone density measurements at 3 and 6 months after surgery was statistically significant only in group A (P = 0.0002 and P = 0.0001, respectively).

CONCLUSIONS

It can be concluded that direct application of the PRP along the fracture lines may enhance the bone regeneration in mandibular fractures.

Evaluation of healing processes of intraosseous defects with and without guided bone regeneration and platelet rich plasma. An animal study

BACKGROUND

In most cases, the natural healing of intrabony defects only leads to restoration of tissue continuity without differentiation and function. However, repair is not regarded to be an optimal treatment method, as confirmed in many clinical cases. Thus it is important to choose a surgical procedure which makes it possible to achieve restitution ad integrum of the bone structure. The choice of the GBR technique is crucial, in terms of the clinical conditions and limitations resulting from the use of a particular material.

OBJECTIVE

The objective of this study has been the analysis of effectiveness of selected surgical treatment techniques of intrabony defects in rabbits.

MATERIALS AND METHODS

Research was conducted on 36 white rabbits. The operation technique was a criterion of division into 3 groups: BG/BOC (Bio-Oss Collagen(®)+Bio-Gide Perio(®)), BOC/PRP (Bio-Oss Collagen(®)+PRP), C (control group). Qualitative and quantitative histopathological evaluation was carried out after 1, 3, 6 and 12 months.

RESULTS

The highest value of the bone surface area 31.9% (SD 1.8) was achieved in BOC/BG group three months after the implantation, while the lowest was revealed in C - group - 12.5% (SD 1.32) one month following the procedure.

CONCLUSIONS

Upon quantitative histological assessment, the bone tissue presented the most intensive osteogenesis within one month from the application of BOC/PRP, whereas this was observed after the application of BOC/BG in later stages. The application of two regenerative methods influenced the rate, quality and overall treatment of intraosseus defects.

Bovine Anorganic Bone Graft Associated with Platelet-Rich Plasma: Histologic Analysis in Rabbit Calvaria

Autogenous bone tissue has regeneration potential; however, this capacity may not be sufficient in larger bone defects. The aim of this study is to histologically evaluate anorganic bovine bone grafts (GenOx Inorg) with or without platelet-rich plasma (PRP). Two bone lesions were created in calvaria of 12 rabbits. The 24 surgical lesions were separated into 3 groups: coagulous, anorganic, and anorganic with PRP. At the 4-week time point, the animals were euthanized and the grafted area removed, fixed in formalin 10% with phosphate buffered saline, 0.1 M, and embedded in paraffin. The histologic parameters analyzed were new bone filling the defect area, presence of giant cells and particles of the graft, and new bone formation associated with the particles. In the coagulous group, defects were filled with fibrous tissue that attached the periosteum and little bone neoformation in the periphery. In anorganic groups with or without PRP, little new bone formation in the periphery of the defect was observed; however, in the center of some defects there was new bone. Moderate presence of giant cells and little new bone formation was associated with the innumerous graft particles. Histologic results revealed no statistically significant differences among the defects new bone fill between the studied groups (P  =  .64). There was no significant difference in the number of giant cells (P  =  .60), graft particles (P  =  .46), and new bone formation around graft particles (P  =  .26), whether PRP was added or not. Anorganic bone, isolated or mixed with PRP, was biocompatible and osteoconductive, while maintaining bone volume.

Effect of different storage media on the regenerative potential of autogenous bone grafts: a histomorphometrical analysis in rabbits

The success of autogenous bone graft is related to the graft cell viability. In bone-grafting procedures, harvested grafts are often maintained in extraoral media while the recipient site is prepared. The aim of this study was to evaluate in vivo the effect of storage media over autogenous bone grafts during the transsurgical time. Two grafts were removed bilaterally from the calvaria of 18 rabbits. One graft was immediately fixed in the mandibular angle (control group), and the other was maintained in air exposure (dry group), 0.9% NaCl solution (saline group), or platelet-poor plasma (PPP group) during 30 minutes and stabilized in the symmetrical location of control grafts. After 28 days, the animals were euthanized and the bone fragments were removed, demineralized, and embedded in paraffin. Histological evaluation was performed under light microscope. Empty lacunae and bone graft area quantification were carried out for the sections. The histomorphometrical analysis revealed reduction of the graft area and increase of empty lacunae in the dry group when compared with control. No significant differences were found in the number of empty lacunae or bone graft area between the saline group and its control and also between the PPP group and its control. The dry group showed more empty lacunae and less graft area than the saline and PPP groups. In accordance with the results, PPP and physiologic solution demonstrated osteocyte preservation and bone graft area maintenance, being satisfactory storage media for autogenous bone grafts during the transsurgical period.

Comparative radiographic evaluation of alveolar bone healing associated with autologous platelet-rich plasma after impacted mandibular third molar surgery

PURPOSE

This study radiographically evaluated the performance of autologous platelet-rich plasma (PRP) applied in tooth sockets.

PATIENTS AND METHODS

Thirty extractions of bilateral impacted mandibular third molars were performed in 15 volunteers (7 men, 8 women; 18 to 22 years old). After extraction of right and left mandibular third molars, the socket at 1 side received the autologous PRP (PRP group) and the other was filled with blood clot (control group). Millimeter periapical radiographs were obtained 7 days, 1 month, and 2, 3, and 6 months postoperatively. Radiographic bone density was quantified 3 times by the same examiner at different moments using HLImage 97 software, and data were statistically analyzed by Statgraf 7.0 software (analysis of variance and Tukey test).

RESULTS

In general, there was significantly faster bone formation in sockets treated with PRP (P < .01). Significant bone formation was observed in the first month (P < .01), second month (P < .05), and third month (P < .01) for the PRP group. No statistical differences were observed on the seventh day and sixth month of investigation, yet there were higher means of radiographic bone density in sockets treated with PRP. In the control group, men exhibited significant bone repair compared with women (P < .05).

CONCLUSION

Autologous PRP was found to accelerate alveolar bone regeneration, and men presented better repair after tooth extraction.