Combination of an allogenic and a xenogenic bone substitute material with injectable platelet-rich fibrin - A comparative in vitro study

Does Injectable Platelet-Rich Fibrin Combined With Autogenous Demineralized Dentine Enhance Alveolar Ridge Preservation? A Randomized Controlled Trial

OBJECTIVE

The present trial evaluated the first-time application of autogenous demineralized dentin graft with injectable platelet-rich fibrin (ADDG + i-PRF) versus autogenous demineralized dentin graft (ADDG), in alveolar ridge preservation (ARP) in the maxillary aesthetic zone.

MATERIAL AND METHODS

Twenty-two maxillary (n = 22) non-molar teeth indicated for extraction were randomized into two groups (n = 11/group). Extracted teeth were prepared into ADDG, implanted into extraction sockets with or without i-PRF amalgamation and covered by collagen sponge. Cone-beam computed tomography scans at baseline and 6 months were compared to assess ridge-dimensional changes. Keratinized tissue width, patient satisfaction, pain score and chair time were recorded. In the course of dental implant placements at 6 months, bone core biopsies of engrafted sites were obtained and analysed histomorphometrically.

RESULTS

Reduction in ridge width was 1.71 ± 1.08 and 1.8 ± 1.35 mm, while reduction in ridge height was 1.11 ± 0.76 and 1.8 ± 0.96 mm for ADDG + i-PRF and ADDG, respectively (p > 0.05). Significant differences in keratinized tissue width reduction were notable between ADDG + i-PRF and ADDG (0.12 ± 0.34 and 0.58 ± 0.34 mm respectively; p = 0.008). Postoperative pain scores were significantly lower in ADDG + i-PRF (p = 0.012). All patients in the two groups were satisfied with no differences in chair time (p > 0.05). No differences in total percentage area of newly formed bone, soft tissue or graft particles were observed between the groups (p > 0.05).

CONCLUSIONS

ADDG alone or in combination with i-PRF yields similar results regarding ARP clinically, quality of the formed osseous tissues, as well as patients' satisfaction. Yet, the addition of i-PRF to ADDG tends to preserve the keratinized tissue and lessen postoperative pain.

Effects of boric acid combined with injectable platelet rich fibrin on the mineralized nodule formation and the viability of human dental pulp stem cells

BACKGROUND

The present study aimed to evaluate the viability of human dental pulp stem cells (hDPSCs) exposed to boric acid (BA) and injectable platelet-rich fibrin (I-PRF).

MATERIALS AND METHODS

hDPSCs were isolated from impacted third molars. Nine milliliters of whole blood was transferred to I-PRF tubes and centrifuged at 700 rpm for 3 minutes. A BA solution was prepared by dissolving BA in a 0.1 g/ml stock solution. The cells were divided into four groups: control, I-PRF, BA, and BA + I-PRF. Cell viability was evaluated using flow cytometry. Mineralized calcium nodules were observed using Alizarin Red staining. The data were analyzed using two-way analysis of variance and Tukey's HSD test (p<0.05).

RESULTS

The highest percentage of viable cells was in the I-PRF group, and the lowest percentage of viable cells was in the BA group at all times. Larger calcium nodules were observed in the BA group compared to the other groups.

CONCLUSION

The use of I-PRF with or without BA had a positive effect on cell viability. BA and I-PRF affected the formation of mineralized calcium nodules. I-PRF and BA may be used in combination because these substances minimally reduce cell viability and promote mineralized nodule formation.

The effect of injectable platelet-rich fibrin and platelet-rich fibrin in regenerative endodontics: a comparative in vitro study

OBJECTIVE

To explore the feasibility of injectable platelet-rich fibrin (i-PRF) in regenerative endodontics by comparing the effect of i-PRF and platelet-rich fibrin (PRF) on the biological behavior and angiogenesis of human stem cells from the apical papilla (SCAPs).

METHODOLOGY

i-PRF and PRF were obtained from venous blood by two different centrifugation methods, followed by hematoxylin-eosin (HE) staining and scanning electron microscopy (SEM). Enzyme-linked immunosorbent assay (ELISA) was conducted to quantify the growth factors. SCAPs were cultured with different concentrations of i-PRF extract (i-PRFe) and PRF extract (PRFe), and the optimal concentrations were selected using the Cell Counting Kit-8 (CCK-8) assay. The cell proliferation and migration potentials of SCAPs were then observed using the CCK-8 and Transwell assays. Mineralization ability was detected by alizarin red staining (ARS), and angiogenesis ability was detected by tube formation assay. Real-time quantitative polymerase chain reaction (RT-qPCR) was performed to evaluate the expression of genes related to mineralization and angiogenesis. The data were subjected to statistical analysis.

RESULTS

i-PRF and PRF showed a similar three-dimensional fibrin structure, while i-PRF released a higher concentration of growth factors than PRF ( P <.05). 1/4× i-PRFe and 1/4× PRFe were selected as the optimal concentrations. The cell proliferation rate of the i-PRFe group was higher than that of the PRFe group ( P <.05), while no statistical difference was observed between them in terms of cell mitigation ( P >.05). More importantly, our results showed that i-PRFe had a stronger effect on SCAPs than PRFe in facilitating mineralization and angiogenesis, with the consistent result of RT-qPCR ( P <.05).

CONCLUSION

This study revealed that i-PRF released a higher concentration of growth factors and was superior to PRF in promoting proliferation, mineralization and angiogenesis of SCAPs, which indicates that i-PRF could be a promising biological scaffold for application in pulp regeneration.

A comparative analysis of particulate bovine bone substitutes for oral regeneration: a narrative review

PURPOSE

Particulate bovine bone substitutes (BS) are commonly used in oral regeneration. However, more literature is needed focusing on comparative analyses among various particulate bovine BS. This study evaluates pre-clinical and clinical data of different particulate bovine BS in oral regeneration.

METHODS

A narrative review was conducted by screening the PubMed database Included in the review were pre-clinical and clinical studies until 2024 comparing a minimum of two distinct particulate bovine BS. In addition to examining general data concerning manufacturing and treatment processes, biological safety, physical and chemical characteristics, and graft resorption, particular emphasis was placed on assessing pre-clinical and clinical data related to ridge preservation, sinus floor elevation, peri-implant defects, and various forms of alveolar ridge augmentation utilizing particulate bovine BS.

RESULTS

Various treatment temperatures ranging from 300 to 1,250 °C and the employment of chemical cleaning steps were identified for the manufacturing process of particulate bovine BS deemed to possess biosecurity. A notable heterogeneity was observed in the physical and chemical characteristics of particulate bovine BS, with minimal or negligible graft resorption. Variations were evident in particle and pore sizes and the porosity of particulate bovine BS. Pre-clinical assessments noted a marginal inclination towards favorable outcomes for particulate bovine BS subjected to higher treatment temperatures. However, clinical data are insufficient. No distinctions were observed regarding ridge preservation, while slight advantages were noted for high-temperature treated particulate bovine BS in sinus floor elevation.

CONCLUSIONS

Subtle variances in both pre-clinical and clinical outcomes were observed in across various particulate bovine BS. Due to inadequate data, numerous considerations related to diverse particulate bovine BS, including peri-implant defects, must be more conclusive. Additional clinical studies are imperative to address these knowledge gaps effectively.

Evaluation of the effect of injectable platelet-rich fibrin (i-PRF) in wound healing and growth factor release in rats: a split-mouth study

This experimental study aimed to evaluate the effects of injectable platelet-rich fibrin (i-PRF) on mucosal healing and the release of growth factors in rats. 40 rats were used; i-PRF was administered in the right buccal area while saline was injected in the left. Cytokeratin, FGF, PDGF, TGF, and VEGF expressions were determined with immunohistochemistry. Gene expressions of EGF, TGF-β, and VEGF were analysed. Epithelialization started on the 3rd day, and connective tissue maturation was more prominent in the i-PRF-applied group. Also, the releases of VEGF, EGF, TGF-β, PDGF, and FGF were higher in the i-PRF group during the 14 days. Gene expression analysis showed that changes in TGF-β at 14 days after i-PRF injection and VEGF after 21 days were statistically significant. The results of this study suggested that autologous i-PRF application enhanced the healing of oral mucosal wounds by increasing the release of growth factors for 21 days.

Ten years of injectable platelet-rich fibrin

The use of platelet-rich fibrin (PRF) has seen widespread advantages over platelet-rich plasma (PRP) in many fields of medicine. However, until 2014, PRF remained clinically available only in its solid clotted form. Modifications to centrifugation protocols and tube technology have led to the development of a liquid injectable version of PRF (i-PRF). This narrative review takes a look back at the technological developments made throughout the past decade and further elaborates on their future clinical applications. Topics covered include improvements in isolation techniques and protocols, ways to further concentrate i-PRF, and the clinical impact and relevance of cooling i-PRF. Next, various uses of i-PRF are discussed, including its use in regenerative periodontology, implantology, endodontics, temporomandibular joint injections, and orthodontic tooth movement. Furthermore, various indications in medicine are also covered, including its use in sports injuries and osteoarthritis of various joints, treatment of diabetic ulcers/wound care, and facial esthetics and hair regrowth. Finally, future applications are discussed, mainly its use as a drug delivery vehicle for small biomolecules, such as growth factors, antibiotics, exosomes, and other medications that may benefit from the controlled and gradual release of biomolecules over time.

Effectiveness of i-PRF in periodontal regeneration - A systematic review and meta-analysis

Background

Periapical diseases are common dental conditions that require non-surgical endodontic intervention (NEI) for successful treatment. However, the impact of diabetes mellitus (DM) on the periapical healing (PH) outcome in diabetic patients remains somewhat unclear. This review aimed to evaluate the PH outcome following endodontic intervention among DM-afflicted individuals.

Methods

A comprehensive search was conducted across multiple electronic databases to identify relevant studies. Specifically devised selection criteria were applied to select studies that assessed PH outcomes in DM sufferers undergoing different treatment protocols. Data extraction and quality assessment were performed following predetermined protocols. ROB - 2 risk assessment tool assessed quality of the included studies.

Results

A total of 11 studies met the inclusion criteria and were included in the investigation. Four studies showed greater occurrence of apical periodontitis and five of them reduced healing and success rate in diabetic as compared to controls. Overall, nine studies showed that diabetes mellitus affected periapical outcome negatively. This suggests that diabetes mellitus is an important factor in the prognosis of endodontic intervention. Assessment tools used were PAI, PR, SC and FD analysis. RoB-2 assessed the included studies to have moderate risk of bias.

Conclusion

This review provided compelling evidence that DM patients experienced a noticeable negative impact on PH outcome as compared to control population. These findings highlight the importance of considering the diabetic status of patients when assessing the prognosis of periapical diseases and planning NEI interventions. Further research is needed to validate these findings and explore potential mechanisms underlying the observed associations.

Platelet-rich fibrin for rehydration and pre-vascularization of an acellular, collagen membrane of porcine origin

OBJECTIVES

Pre-vascularization of the collagen membranes with autologous platelet concentrates is a standard procedure in oral and maxillofacial surgery. This study analyzed the possible interaction of an acellular collagen membrane of porcine origin (NM) with platelet-rich fibrin (PRF) regarding its rehydration protocol with differences in pH values and effect on angiogenesis.

MATERIALS AND METHODS

NM was analyzed alone and combined with solid PRF by plotting or co-culturing with injectable PRF. Different media (venous blood, buffer solution with a fixed pH value of 7, saline solution, and injectable PRF) were used to analyze the influence on pH value during rehydration. Chorion allantois membrane assay (CAM) was applied to check pro-angiogenic effects after 24, 48, and 72 h, followed by immunohistochemical analysis.

RESULTS

Rehydration in injectable PRF showed acidity over time (p < 0.05). A definite pro-angiogenic effect of NM alone was found regarding neo-vessel formation supported by the respective light microscopically analysis without significant differences to PRF alone (p > 0.005). This pro-angiogenic effect could not be exaggerated when NM was combined with liquid/solid PRF (each p > 0.005).

CONCLUSIONS

Rehydration with liquid PRF of the collagen membrane results in acidity compared to a saline solution or patient's blood. The significant pro-angiogenic potential of the membrane alone resulted in enhanced neo-vessel formation that could not be optimized with the addition of PRF.

CLINICAL RELEVANCE STATEMENT

Using injectable PRF for rehydration protocol of the collagen membrane leads to acidosis that can ultimately optimize wound healing. Differences in the physio-mechanical interplay of collagen matrices and autologous platelet concentrates must result in clinical algorithms if pre-vascularization can maximize outcomes.

Efficacy of injectable platelet-rich fibrin on clinical and biochemical parameters in non-surgical periodontal treatment: a split-mouth randomized controlled trial

OBJECTIVES

The purpose of this clinical trial was to evaluate the potential clinical and biochemical effects of injectable platelet-rich fibrin (i-PRF) application adjunct to scaling and root planning (ScRp) in deep periodontal pockets.

MATERIALS AND METHODS

In this split-mouth-designed study, 17 patients with 34 deep periodontal pockets were randomly treated with ScRp + i-PRF (test group) and ScRp + saline (control group). Clinical periodontal measurements were recorded at baseline, 1st, 3rd, and 6th months after the treatments. The levels of vascular endothelial growth factor (VEGF), tumor necrosis factor-α (TNF-α), and interleukin (IL)-10 in gingival crevicular fluid (GCF) samples were analyzed using the ELISA method at baseline, 7th, and 14th days.

RESULTS

Clinical periodontal parameters showed significant improvements with both treatment modalities. Mean pocket reduction (PD) and clinical attachment (CAL) gain were significantly higher in the test group than in controls at follow-up visits (p < 0.05). In the test group, gingival recession (GR) values were significantly lower compared to the control group. VEGF and IL-10 levels in the test group were significantly higher than in controls at the 14th day, and TNF-α levels were found significantly lower in the test group at the 7th and 14th days.

CONCLUSIONS

Especially in the test group, the significant increase in VEGF and IL-10 expressions and the decrease in TNF-α levels may have accelerated the periodontal healing observed in the clinical parameters.

CLINICAL RELEVANCE

The result of the present study demonstrated the beneficial effects of adjunctive i-PRF administration during non-surgical periodontal treatment of deep periodontal pockets.

CLINICAL TRIAL REGISTRATION NUMBER

NCT05753631.

The role and mechanism of platelet-rich fibrin in alveolar bone regeneration

Platelet-rich fibrin (PRF), as an autologous blood preparation, has been receiving increasing attention in recent years and has been successfully applied in various clinical treatments for alveolar bone regeneration in the oral field. This review focuses on analyzing and summarizing the role and mechanism of PRF in alveolar bone regeneration. We first provide a brief introduction to PRF, then summarize the mechanisms by which PRF promotes alveolar bone regeneration from three aspects: osteogenesis mechanism, bone induction mechanism, and bone conduction mechanism, involving multiple signaling pathways such as Smad, ERK1/2, PI3K/Akt, and Wnt/β-catenin. We also explore the various roles of PRF as a scaffold, filler, and in combination with bone graft materials, detailing how PRF promotes alveolar bone regeneration and provides a wealth of experimental evidence. Finally, we summarize the current applications of PRF in various oral fields. The role of PRF in alveolar bone regeneration is becoming increasingly important, and its role and mechanism are receiving more and more research and understanding. This article will provide a reference of significant value for research in related fields. The exploration of the role and mechanism of PRF in alveolar bone regeneration may lead to the discovery of new therapeutic targets and the development of more effective and efficient treatment strategies.

The Effects of Platelet-Rich Fibrin in the Behavior of Mineralizing Cells Related to Bone Tissue Regeneration-A Scoping Review of In Vitro Evidence

Platelet-rich fibrin (PRF) is a second-generation blood concentrate that serves as an autologous approach for both soft and hard tissue regeneration. It provides a scaffold for cell interaction and promotes the local release of growth factors. PRF has been investigated as an alternative to bone tissue therapy, with the potential to expedite wound healing and bone regeneration, though the mechanisms involved are not yet fully understood. This review aims to explore the in vitro evidence of PRF's effects on the behavior of mineralizing cells related to bone tissue regeneration. A systematic electronic search was conducted up to August 2023, utilizing three databases: PubMed, Web of Science, and Scopus. A total of 76 studies were selected, which presented in vitro evidence of PRF's usefulness, either alone or in conjunction with other biomaterials, for bone tissue treatment. PRF membranes' influence on the proliferation, differentiation, and mineralization of bone cells is linked to the constant release of growth factors, resulting in changes in crucial markers of bone cell metabolism and behavior. This further reinforces their therapeutic potential in wound healing and bone regeneration. While there are some notable differences among the studies, the overall results suggest a positive effect of PRF on cell proliferation, differentiation, mineralization, and a reduction in inflammation. This points to its therapeutic potential in the field of regenerative medicine. Collectively, these findings may help enhance our understanding of how PRF impacts basic physiological processes in bone and mineralized tissue.

Efficacy of mixture of injectable-platelet-rich fibrin and type-1 collagen particles on the closure of through-and-through periapical bone defects: A randomized controlled trial

AIM

To determine the efficacy of a combination of injectable-platelet-rich fibrin and type-1 collagen particles on the healing of through-and-through periapical bone defect and subsequent closure of bony window.

METHODOLOGY

The clinical trial was registered in ClinicalTrials.gov (NCT04391725). Thirty-eight individuals with radiographic evidence of periapical radiolucency in maxillary anterior teeth and confirmed loss of palatal cortical plates in cone beam computed tomographic imaging were randomly assigned to either the experimental group (n = 19) or the control group (n = 19). A mixture of i-PRF and collagen as a graft was applied to the defect in adjunct to periapical surgery in the experimental group. No guided bone regeneration procedures were used in the control group. The healing was evaluated using Molven's (2D) and modified PENN 3D (3D) criteria. Percentage reduction of the buccal and palatal bony window area, and complete closure of through-and-through periapical bony window (tunnel defect) were assessed using Radiant Diacom viewer software (Version 4.0.2). The reduction in the periapical lesion area and volume was measured using Corel DRAW and ITK Snap software.

RESULTS

Thirty-four participants (18 and 16 in the experimental and control groups respectively) reported for follow-up at 12 months. There was 96.9% and 97.96% reduction of buccal bony window area in the experimental and control groups respectively. Similarly, palatal window showed 99.03% and 100% reduction in the experimental and control groups respectively. No significant difference in both buccal and palatal window reduction was noticed between the groups. A total of 14 cases (seven in the experimental group and seven in the control group) showed complete closure of through-and-through bony window. No significant difference in clinical, 2D and 3D radiographic healing, percentage reduction in area and volume was observed between the experimental and control groups (p > .05). Neither the area nor the volume of lesion, and the size of buccal or palatal window had significant effect on healing of through-and-through defects.

CONCLUSION

Endodontic microsurgery results in high success rate in large periapical lesions with through-and-through communication with more than 80% reduction in volume of lesion and size of both buccal and palatal window after 1 year. A mixture of type-1 collagen particles and i-PRF, adjunct to periapical micro-surgery did not improve the healing in through-and-through periapical defects.

Use of Injectable Platelet-Rich Fibrin Accompanied by Bone Graft in Socket Endurance: A Radiographic and Histological Study

Background Ridge preservation became a crucial dental health issue and strategy to keep away from ridge defacement after post-tooth loss. The recent scientific evolution of platelet-rich fibrin (PRF) comprises a parenteral formulation of PRF. The combined allograft for socket preservation gives benefits. In this study, bone allografts, demineralized freeze-dried bone allografts (DFDBA) and freeze-dried bone allografts (FDBA) are used in a 30:70 ratio alone or in combination with injectable PRF (I-PRF) for socket preservation. Methods This study is a radiographic and histological examination conducted on 60 participants aged between 19-65 years. Participating patients agreed voluntarily that they would not bear any fixed prosthesis for the next nine months and plan for implanted teeth placement, including multi-rooted mandibular molars denticles. Both groups received atraumatic extraction; then, the socket was preserved with bone allograft alone in the control group and bone allograft mixed with I-PRF, forming sticky bone, in the experimental group. Clinical, radiological, and histological assessments were taken at the inception stage, three months, six months, and nine months. A multivariate regression model and a generalized estimating equation (GEE) model were used to analyse the effects of these changes on outcomes. Results In all the parameters, the test group indicated a good amount of bone growth with increasing intervals of time for bone height radiographically with statistically significant difference present (p<0.05) and histologically after nine months when socket site grafted with bone graft in combination with I-PRF. Conclusion This study's results demonstrated that I-PRF possesses the potential to regenerate and heal in the tooth-extracted socket. This study further recommends the implementation of I-PRF in safeguarding and conserving the raised rim of the tooth. Future research should take place on the osteogenic capability of I-PRF in more comprehensive ridge accession surgical procedures and additional expanding and improving capacities in periodontal reconstruction.

Evaluation of the Effect of Injectable Platelet-rich Fibrin on Palatal Wound Healing: A Two-arm Randomized Controlled Clinical Trial

AIM

This study aimed to evaluate the effect of injectable platelet-rich fibrin (i-PRF) as a potential catalyst for the acceleration of palatal wound healing after subepithelial connective tissue graft (SCTG) harvesting.

MATERIALS AND METHODS

Referred patients to the Department of Periodontology with the complication of the gingival recession were examined. Thirty participants were chosen for root coverage surgeries with SCTGs, and randomly distributed into two groups; the study group (n = 15) with i-PRF was applied, and the control group (n = 15) without i-PRF. The wound healing index was evaluated on the 7th, 14th, and 30th days of the treatment. Palatal tissue thickness was measured before the treatment and at the 1st, 2nd, and 3rd months after the treatment.

RESULTS

The study group improved significantly the early healing over the control group on days 7 and 14 (p < 0.01), whereas no difference in the first month (p > 0.05) between the groups. Moreover, the study group showed higher tissue thickness mean in the first and second month (p < 0.01), but in the third month, there were no significant differences (p > 0.05) between both groups.

CONCLUSION

The i-PRF has favorable effects on the healing process by enhancing wound healing and increasing the tissue thickness in the palate after SCTG harvesting.

CLINICAL SIGNIFICANCE

For clinicians, it is important to know that we can use biological materials to accelerate healing in general, such as i-PRF. In this study, we used it in the palate, which may accelerate the healing so that we can repeatedly use the same area of the patient's palate for more than one occasion faster.

Injectable platelet-rich fibrin with demineralized freeze-dried bone allograft compared to demineralized freeze-dried bone allograft in intrabony defects of patients with stage-III periodontitis: a randomized controlled clinical trial

Aim

The current randomized controlled clinical trial assessed the effect of injectable platelet-rich fibrin (I-PRF) combined with demineralized freeze-dried bone allograft (DFDBA) compared to DFDBA alone in the management of intrabony defects of stage-III periodontitis patients.

Methodology

Following sample size calculation, twenty stage-III periodontitis patients with ≥ 5 mm clinical attachment level (CAL)-loss and ≥ 3 mm intrabony defects were randomized into test (I-PRF + DFDBA; n = 10) and control (DFDBA; n = 10) groups. CAL (primary outcome), periodontal probing depth (PPD), gingival recession depth (GRD), full-mouth plaque scores (FMPS), full-mouth bleeding scores (FMBS), radiographic linear defect depth (RLDD), and bone fill (secondary outcomes) were examined at baseline, 3, 6, and 9 months post-surgically.

Results

I-PRF + DFDBA and DFDBA independently demonstrated significant intragroup CAL-gain, PPD-, and RLDD-reduction at 3, 6, and 9 months (p < 0.05), with no significant intergroup differences observed (p > 0.05). CAL-gain (mean ± SD) of 2.40 ± 0.70 mm and 2.50 ± 0.85 mm and PPD-reduction of 3.50 ± 1.18 mm and 2.80 ± 0.42 mm were demonstrated for I-PRF + DFDBA and DFDBA at 9 months respectively. Both groups showed significant intragroup RLDD improvement, with a RLDD of 3.58 ± 0.66 mm and 3.89 ± 1.57 mm for I-PRF + DFDBA and DFDBA at 9 months respectively. Stepwise linear regression analysis revealed that baseline RLDD and bone fill at 9 months were significant predictors of CAL (p < 0.05).

Conclusion

Within the present study’s limitations, DFDBA with or without I-PRF resulted in significant improvement in clinical and radiographic periodontal parameters in the surgical treatment of periodontal intrabony defects of stage-III periodontitis patients. Addition of I-PRF to DFDBA does not appear to significantly enhance the DFDBA’s reparative/regenerative outcomes.

Clinical relevance

Within the current study’s limitations, routinely adding I-PRF to DFDBA cannot be recommended to significantly improve DFDBA’s treatment outcomes in intrabony defects.

Progressive Platelet Rich Fibrin tissue regeneration matrix: Description of a novel, low cost and effective method for the treatment of chronic diabetic ulcers-Pilot study

INTRODUCTION

Chronic lower limb ulcers (CLLU) are those injuries that persist for more than six weeks despite adequate care. They are relatively common; it is estimated that 10/1,000 people will develop CLLU in their lifetime. Diabetic ulcer, because of its unique pathophysiology (association between neuropathy, microangiopathy, and immune deficiency), is considered one of the most complex and difficult etiologies of CLLU for treatment. This treatment is complex, costly, and sometimes frustrating, as it is often ineffective, which worsens the quality of life of patients and makes its treatment a challenge.

OBJECTIVE

To describe a new method for treating diabetic CLLU and the initial results of using a new autologous tissue regeneration matrix.

METHOD

This is a pilot, prospective, an interventional study that used a novel protocol of autologous tissue regeneration matrix for the treatment of diabetic CLLU.

RESULTS

Three male cases with a mean age of 54 years were included. A total of six Giant Pro PRF Membrane (GMPro) were used varying their application between one to three sessions during treatment. A total of 11 liquid phase infiltrations were performed varying their application between three and four sessions. The patients were evaluated weekly and a reduction in the wound area and scar retraction was observed during the period studied.

CONCLUSION

The new tissue regeneration matrix described is an effective and low-cost method for the treatment of chronic diabetic ulcers.

The application of injectable platelet-rich fibrin in regenerative dentistry: A systematic scoping review of In vitro and In vivo studies

Background

Ongoing research in the dental field has begun to focus on the use of injectable platelet-rich fibrin (I-PRF) as a regenerative tool with the potential to prompt tissue regeneration. In this regard, this systematic scoping review aimed to collect, map, and appraise the in vitro and in vivo studies regarding the role of I-PRF in or soft and hard tissue regeneration in relation to oral and maxillofacial structures.

Methods

A systematic electronic search of Medline, Scopus, Web of Science, and Embase databases was performed from 2000 to December 2021 using a combination of keywords. All in vitro and in vivo studies, written in English and concerning the potential role of I-PRF in regenerative dentistry were considered.

Results

In total, 18 in vitro studies, 5 animal studies, 6 case reports, and 31 clinical studies have evaluated the effect of I-PRF on oral and maxillofacial soft and hard tissue regeneration. The investigated studies verified the anti-inflammatory, anti-microbial efficacy and the positive effects of I-PRF application for wound, periodontal, bone, cartilage, and pulp regeneration, as well as acceleration in tooth movement during orthodontic treatment.

Conclusions

Current literature approves the feasibility of I-PRF application as a promising regenerative adjunct to dental procedures.

Effect of Injectable Platelet-Rich Fibrin with a Nano-Hydroxyapatite Bone Graft on the Treatment of a Grade II Furcation Defect

Background: Periodontal diseases lead to bone loss, crestal defects and even loss of the tooth, which also further makes it difficult to replace the tooth. Autogenous bone grafts are considered the gold standard in bone regenerative procedures. This study aimed to compare and evaluate the bone regenerative effects of i-PRF (Injectable- Platelet-rich fibrin) with a bone graft and a bone graft alone in mandibular grade II furcation defects over a period of 9 months. Method: This was a comparative study of 12 participants, who were randomly selected and grouped into two groups: test and control. Following phase I therapy, both groups were subjected to open flap debridement. In the test group, after debridement, a nano-hydroxyapatite bone graft mixed with i-PRF was inserted, whereas in the control group only a nano-hydroxyapatite bone graft was inserted. The clinical parameters such as plaque index (PI), gingival index (GI), pocket probing depth (PPD), clinical attachment level (CAL), horizontal probing depth (HPD) and vertical probing depth (VPD) were recorded at baseline, 3 months, 6 months and 9 months following the surgery. The bone area fill (BAF) was assessed using intraoral periapical radiographs (IOPARs) taken at baseline and 9 months after surgery. Results: At the baseline, there was no statistically significant difference between the tested parameters. After 9 months all the clinical parameters, PI, GI, PPD, CAL, HPD and VPD as well as radiographic bone fill showed a significant increase in both the groups (p < 0.05) (PI-TGr; CGr−VPD—3.5 ± 0.54 to 0.66 ± 0.51; 3.3 ± 0.81 to 2 ± 0.63/BAF—2.9 ± 0.88 to 5.6 ± 1.10; 3.4 ± 1.39 to 3.9 ± 1.4). On comparison the test group showed better results for each clinical parameter. Conclusion: The results showed increased improvement in clinical conditions in both groups, although better results were seen in the group where i-PRF with a nano-HA bone graft was used in the furcation defect.

Effects of advanced platelet-rich fibrin combined with xenogenic bone on human periodontal ligament stem cells

OBJECTIVES

In this study, we aimed to investigate the effects of a mixture of advanced platelet-rich fibrin (A-PRF) and xenogenic bone substitute material (XBSM) on the proliferation and migration of human periodontal ligament stem cells (hPDLSCs) based on the in vitro release of growth factors.

MATERIAL AND METHODS

The concentrations of platelet-derived growth factor-AB (PDGF-AB) and vascular endothelial growth factor (VEGF) released by the A-PRF-XBSM mixture were estimated using enzyme-linked immunoassay for up to 7 d. The A-PRF-XBSM mixture exudate was incubated with hPDLSCs. At Days 1, 3, 5, and 7, cell proliferation and migration were investigated by cell counting and wound-healing assays.

RESULTS

PDGD-AB and VEGF were released from the A-PRF-XBSM mixture exudate for up to 7 days. hPDLSCs were cultured in media with various concentrations of the A-PRF-XBSM mixture exudate and exhibited their proliferation and migration ability. Furthermore, the factors released from the 100% A-PRF-XBSM mixture exudate had a substantial effect on cell migration, whereas those released from 4% and 20% A-PRF-XBSM mixture exudates stimulated hPDLSC proliferation.

CONCLUSIONS

A-PRF-XBSM mixture continuously released growth factors over 7 days and enhanced hPDLSC proliferation and migration. Therefore, A-PRF in combination with XBSM might provide potential advantages for periodontal tissue regeneration.

Hyaluronic Acid with Bone Substitutes Enhance Angiogenesis In Vivo

Introduction: The effective induction of angiogenesis is directly related to the success of bone-substitute materials (BSM) for maxillofacial osseous regeneration. Therefore, the addition of pro-angiogenic properties to a commercially available bovine bone-substitute material in combination with hyaluronic acid (BSM+) was compared to the same bone-substitute material without hyaluronic acid (BSM) in an in-vivo model. Materials and Methods: BSM+ and BSM were incubated for six days on the chorioallantoic membrane (CAM) of fertilized chicken eggs. Microscopically, the number of vessels and branching points, the vessel area and vessel length were evaluated. Subsequently, the total vessel area and brightness integration were assessed after immunohistochemical staining (H&E, alphaSMA). Results: In the BSM+ group, a significantly higher number of vessels (p < 0.001), branching points (p = 0.001), total vessel area (p < 0.001) as well as vessel length (p = 0.001) were found in comparison to the BSM group without hyaluronic acid. Immunohistochemically, a significantly increased total vessel area (p < 0.001 for H&E, p = 0.037 for alphaSMA) and brightness integration (p = 0.047) for BSM+ in comparison to the native material were seen. Conclusions: The combination of a xenogenic bone-substitute material with hyaluronic acid significantly induced angiogenesis in vivo. This might lead to a faster integration and an improved healing in clinical situations.

The feasibility of injectable PRF (I-PRF) for bone tissue engineering and its application in oral and maxillofacial reconstruction: From bench to chairside

Among all the biomaterials introduced in the field of bone tissue engineering, injectable platelet-rich fibrin (I-PRF) has recently gained considerable attention. I-PRF, as a rich source of biologically active molecules, is a potential candidate which can be easily obtained in bedside and constitutes several biological factors which can result in higher anti-bacterial, anti-inflammatory and regenerative capabilities. According to the studies evaluating the osteogenic efficacy of I-PRF, this biomaterial has exhibited favorable outcomes in terms of adhesion, differentiation, migration, proliferation and mineralization potential of stem cells. In addition, the injectability and ease-of-applicability of this biomaterial has led to its various clinical applications in the oral and maxillofacial bone regeneration such as ridge augmentation, sinus floor elevation, cleft palate reconstruction and so on. Furthermore, to enhance the clinical performance of I-PRF, albumin gel-PRF as a long-lasting material for long-term utilization has been recently introduced with a gradual increase in growth factor release pattern. This review provides a comprehensive approach to better evaluate the applicability of I-PRF by separately appraising its performance in in-vitro, in-vivo and clinical situations. The critical approach of this review toward the different production protocols and different physical and biological aspects of I-PRF can pave the way for future studies to better assess the efficacy of I-PRF in bone regeneration.

The adjunctive effect of autologous platelet concentrates on orthodontic tooth movement: A systematic review and meta-analysis of current randomized controlled trials

OBJECTIVE

To evaluate the effectiveness of autologous platelet concentrates (APCs) as adjuncts on accelerating orthodontic tooth movement (OTM) of the human subjects undergoing orthodontic treatment and to critically appraise the available literature.

METHODS AND MATERIALS

Five electronic databases (PubMed, Scopus, Web of Science, Embase, and Cochrane Central Register of Controlled Trials) were searched from 2000 up to May 2021 to retrieve eligible randomized controlled trials (RCTs) investigating patients who underwent orthodontic treatment that involved OTM of maxillary and mandibular incisors and canines. All the enrolled cases were treated with APCs and had no local or systemic interfering factors. The quality of the included studies was assessed using the modified JADAD scale. The effect sizes were assessed using mean difference (MD). The heterogeneity analysis was conducted using (I²) statistic at α=0.10.

RESULTS

Finally, seven RCTs were included in the qualitative, and two RCTs were included in the quantitative analysis. The meta-analysis was performed regarding the effect of injectable platelet-rich fibrin (I-PRF) on the rate of canine tooth movement in millimeters at different intervals of the 1^st, 2^nd, and 3^rd months. In the 1^st month, I-PRF (WMD:0.12mm, CI95% -5.01 to 5.24, I²=90%) did not significantly affect OTM. In the 2^nd month, I-PRF (WMD:0.66mm, CI95% 0.60 to 0.73, I²=10%) significantly increased the OTM. However, in the 3^rd month, I-PRF did not significantly increase the OTM (WMD:0.54mm, CI95% -1.38 to 2.47, I²=67%).

CONCLUSIONS

According to the low certainty of evidence about this topic, providing a definite conclusion is not possible. However, applying I-PRF seems to be efficient in accelerating the OTM of the canines. Further high-quality studies with larger sample sizes will be indispensable to validate this conclusion.

Non-Interventional Prospective Observational Study of Platelet Rich Fibrin as a Therapy Adjunctive in Patients with Medication-Related Osteonecrosis of the Jaw

BACKGROUND

Medication-related osteonecrosis (MRONJ) of the jaw is a severe and feared side effect of antiresorptive therapy in the oncological setting. With growing evidence that impaired angiogenesis may represent a key factor in pathogenesis, the aim of this study was to evaluate an autologous platelet concentrate as a possible additive in surgical therapy to optimize vascularization and, subsequently, resolution rates.

MATERIAL AND METHODS

A non-interventional, prospective, multicenter study was conducted, and all patients with stage I-III MRONJ, undergoing antiresorptive therapy for an oncological indication, were included. The necrosis was treated surgically without (study arm A) or with (arm B) the addition of an autologous platelet concentrate (platelet-rich fibrin, PRF).

RESULTS

After 5, 14, and 42 days postoperative, wound healing (primary outcome: mucosal integrity) as well as downstaging, pain perception, and oral health-related quality of life (secondary outcome) were assessed via clinical evaluation. Among the 52 patients included, primarily with MRONJ stage I and II, the use of PRF as an additive in surgical therapy did not display a significant advantage for wound healing (p = 0.302), downstaging (p = 0.9), pain reduction (p = 0.169), or quality of life (p = 0.9).

SUMMARY

In conclusion, PRF as an adjunct did not significantly optimize wound healing. Further, no significant changes in terms of downstaging, pain sensation, and oral health-related quality of life were found.

Second generation liquid platelet concentrates: A literature review

Liquid or injectable platelet rich fibrin (PRF) is a second-generation platelet concentrate which is completely autologous and free of external additives like bovine thrombin and calcium chloride. Additionally, it is the only one to be obtained in a liquid form among the second generation platelet concentrates. This allows for wide applications such as to maximize injections or mixing with biomaterials such as bone grafts or antibiotics. Since it was first introduced in 2015, several modifications of the original protocol have been proposed which aim at maximizing its biological and mechanical properties. This includes changes in centrifugation speed, time, and so on. The aim of this review is to summarize the various modifications of the injectable/liquid formation of PRF as well as to discuss the potential applications and future research direction.

Efficacy of i-PRF in regenerative endodontics therapy for mature permanent teeth with pulp necrosis: study protocol for a multicentre randomised controlled trial

BACKGROUND

Dental pulp necrosis, a common health problem, is traditionally treated with root canal therapy; however, it fails in restoring the vitality of damaged pulp. Most studies regarding regenerative endodontic therapy (RET) are limited to the treatment of immature necrotic teeth. Given that injectable platelet-rich fibrin (i-PRF) has shown great potential in regenerative medicine as a novel platelet concentration, this study is designed to explore whether i-PRF can serve as a biological scaffold, extending the indications for RET and improving the clinical feasibility of RET in mature permanent teeth with pulp necrosis.

METHODS

This is a randomised, double-blind, controlled, multicentre clinical trial designed to evaluate the clinical feasibility of RET for mature permanent teeth with pulp necrosis and to compare the efficacy of i-PRF and blood clots as scaffolds in RET. A total of 346 patients will be recruited from three centres and randomised at an allocation ratio of 1:1 to receive RET with either a blood clot or i-PRF. The changes in subjective symptoms, clinical examinations, and imaging examinations will be tracked longitudinally for a period of 24 months. The primary outcome is the success rate of RET after 24 months. The secondary outcome is the change in pulp vitality measured via thermal and electric pulp tests. In addition, the incidence of adverse events such as discolouration, reinfection, and root resorption will be recorded for a safety evaluation.

DISCUSSION

This study will evaluate the clinical feasibility of RET in mature permanent teeth with pulp necrosis, providing information regarding the efficacy, benefits, and safety of RET with i-PRF. These results may contribute to changes in the treatment of pulp necrosis in mature permanent teeth and reveal the potential of i-PRF as a novel biological scaffold for RET.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04313010 . Registered on 19 March 2020.

The Influence of Hyaluronic Acid Biofunctionalization of a Bovine Bone Substitute on Osteoblast Activity In Vitro

Bovine bone substitute materials (BSMs) are used for oral bone regeneration. The objective was to analyze the influence of BSM biofunctionalization via hyaluronic acid (HA) on human osteoblasts (HOBs). BSMs with ± HA were incubated with HOBs including HOBs alone as a negative control. On days 3, 7 and 10, cell viability, migration and proliferation were analyzed by fluorescence staining, scratch wound assay and MTT assay. On days 3, 7 and 10, an increased cell viability was demonstrated for BSM+ compared with BSM- and the control (each p ≤ 0.05). The cell migration was enhanced for BSM+ compared with BSM- and the control after day 3 and day 7 (each p ≤ 0.05). At day 10, an accelerated wound closure was found for the control compared with BSM+/- (each p < 0.05). The highest proliferation rate was observed for BSM+ on day 3 (p ≤ 0.05) followed by BSM- and the control (each p ≤ 0.05). At day 7, a non-significantly increased proliferation was shown for BSM+ while the control was higher than BSM- (each p < 0.05). The least proliferation activity was observed for BSM- (p < 0.05) at day 10. HA biofunctionalization of the BSMs caused an increased HOB activity and might represent a promising alternative to BSM- in oral bone regeneration.

Possible Implications for Improved Osteogenesis? The Combination of Platelet-Rich Fibrin With Different Bone Substitute Materials

Bone substitute materials (BSM) are widely used in oral regeneration, but sufficient angiogenesis is crucial for osteogenesis. The combination of BSM with autologous thrombocyte concentrations such as platelet-rich fibrin (PRF) may represent a clinical approach to overcome this limitation. This study analyzes the early influence on osteoblast (HOB) in vitro. Here, four different BSM (allogeneic, alloplastic, and two of xenogeneic origin) were combined with PRF. After the incubation with osteoblasts for 24 h, cell viability, migration, and proliferation were assessed. Next, marker of proliferation, migration, and differentiation were evaluated on gene and protein levels in comparison to the native BSM and osteoblast alone. Addition of PRF increased viability for both the xenogeneic BSM (p = 0.0008, p = 0.032, respectively) in comparison to HOB and vs. native BSM (p = 0.008), and led to a tendency for increased cell proliferation and migration for all BSM (each p > 0.05). On gene basis, allogeneic and alloplastic BSM displayed a significantly increased RUNX2 expression (each p = 0.050). Expression of alkaline phosphatase for alloplastic (p = 0.050) and collagen-1 for xenogeneic BSM (p = 0.05) were significantly increased in combination with PRF. In addition, bone morphogenic protein was expressed significantly higher when xenogeneic material was combined with PRF in comparison to HOB alone (each p = 0.05). In summary, the combination of PRF with different BSM increases initial viability and may influence early proliferation and migration potential of osteoblast via RUNX2, alkaline phosphatase, collagen, and BMP2 especially in combination with alloplastic and xenogeneic BSM. Biofunctionalization of BSM using PRF might improve osteogenesis and extend the range of indications.

Activation of Human Osteoblasts via Different Bovine Bone Substitute Materials With and Without Injectable Platelet Rich Fibrin in vitro

INTRODUCTION

The aim of the in vitro study was to compare the effect of four bovine bone substitute materials (XBSM) with and without injectable platelet-reach fibrin for viability and metabolic activity of human osteoblasts (HOB) as well as expression of alkaline phosphatase (ALP), bone morphogenetic protein 2 (BMP-2), and osteonectin (OCN).

MATERIALS AND METHODS

Cerabone® (CB), Bio-Oss® (BO), Creos Xenogain® (CX) and MinerOss® X (MO) ± i-PRF were incubated with HOB. At day 3, 7, and 10, cell viability and metabolic activity as well as expression of ALP, OCN, and BMP-2, was examined.

RESULTS

For non-i-PRF groups, the highest values concerning viability were seen for CB at all time points. Pre-treatment with i-PRF increased viability in all groups with the highest values for CB-i-PRF after 3 and 7 and for CX-i-PRF after 10 days. For metabolic activity, the highest rate among non-i-PRF groups was seen for MO at day 3 and for CB at day 7 and 10. Here, i-PRF groups showed higher values than non-i-PRF groups (highest values: CB + i-PRF) at all time points. There was no difference in ALP-expression between groups. For OCN expression in non-i-PRF groups, CB showed the highest values after day 3, CX after day 7 and 10. Among i-PRF-groups, the highest values were seen for CX + i-PRF. At day 3, the highest BMP-2 expression was observed for CX. Here, for i-PRF groups, the highest increase was seen for CX + i-PRF at day 3. At day 7 and 10, there was no significant difference among groups.

CONCLUSION

XBSM sintered under high temperature showed increased HOB viability and metabolic activity through the whole period when compared to XBSM manufactured at lower temperatures. Overall, the combination of XBSM with i-PRF improved all cellular parameters, ALP and BMP-2 expression at earlier stages as well as OCN expression at later stages.

Does Platelet-Rich Fibrin Enhance the Early Angiogenetic Potential of Different Bone Substitute Materials? An In Vitro and In Vivo Analysis

The impaired angiogenic potential of bone substitute materials (BSMs) may limit regenerative processes. Therefore, changes in the angiogenetic properties of different BSMs in combination with platelet-rich fibrin (PRF) in comparison to PRF alone, as well as to native BSMs, were analyzed in vitro and in vivo to evaluate possible clinical application. In vitro, four BSMs of different origins (allogeneic, alloplastic, and xenogeneic) were biofunctionalized with PRF and compared to PRF in terms of platelet interaction and growth factor release (vascular endothelial growth factor (VEGF), tissue growth factor ß (TGFß) and platelet-derived growth factor (PDGF)) after 15 min. To visualize initial cell–cell interactions, SEM was performed. In vivo, all BSMs (±PRF) were analyzed after 24 h for new-formed vessels using a chorioallantoic membrane (CAM) assay. Especially for alloplastic BSMs, the addition of PRF led to a significant consumption of platelets (p = 0.05). PDGF expression significantly decreased in comparison to PRF alone (all BSMs: p < 0.013). SEM showed the close spatial relation of each BSM and PRF. In vivo, PRF had a significant positive pro-angiogenic influence in combination with alloplastic (p = 0.007) and xenogeneic materials (p = 0.015) in comparison to the native BSMs. For bio-activated xenogeneic BSMs, the branching points were also significantly increased (p = 0.005). Finally, vessel formation was increased for BSMs and PRF in comparison to the native control (allogeneic: p = 0.046; alloplastic: p = 0.046; and xenogeneic: p = 0.050). An early enhancement of angiogenetic properties was demonstrated when combining BSMs with PRF in vitro and led to upregulated vessel formation in vivo. Thus, the use of BSMs in combination with PRF may trigger bony regeneration in clinical approaches.

A collagen membrane influences bone turnover marker in vivo after bone augmentation with xenogenic bone

Background

The aim was to compare early biochemical and histological osseous healing of chronic mandibular defects regenerated with bovine bone substitute with and without collagen membrane in vivo.

Methods

Eight weeks after formation of a lateral full-thickness perforating bone defect in the mandible of 40 rabbits, bovine bone substitute with (“+”;n = 20) and without (“-”;n = 20) collagen membrane was applied. Blood and bone was collected 24, 72 h, 7, 14 and 21 days after surgery. Total acid phosphatase, bone acid phosphatase, total alkaline phosphatase and bone alkaline phosphatase activities were compared between groups. Formation of new bone was quantified histologically for all time points.

Results

Twenty-four hours after surgery, bone alkaline phosphatase was significantly elevated in “+” group when compared to “-” (p=0.012). After 72 hours, all bone turnover markers except for total acid phosphatase (p=0.078) where significantly elevated in “+” (all p < 0.05). Fourteen days after surgery, the significant highest values for all bone turnover markers were detected in “-” (all p < 0.05). A significant difference in favor of group “-” could also be detected after 3 weeks in terms of both acid phosphatases (p < 0.05). In histology, no significant differences could be detected.

Conclusion

Bone regeneration with bovine bone substitute material and collagen membrane shows a significantly earlier bone remodeling activity but does not seem to influence formation of new bone in histological samples.

In Vivo Modulation of Angiogenesis and Immune Response on a Collagen Matrix via Extracorporeal Shockwaves

The effective management of tissue integration and immunological responses to transplants decisively co-determines the success of soft and hard tissue reconstruction. The aim of this in vivo study was to evaluate the eligibility of extracorporeal shock wave therapy (ESWT) with respect to its ability to modulate angiogenesis and immune response to a collagen matrix (CM) for tissue engineering in the chorioallantoic membrane (CAM) assay, which is performed with fertilized chicken eggs. CM were placed on the CAM on embryonic development day (EDD) 7; at EDD-10, ESWT was conducted at 0.12 mJ/mm² with 500 impulses each. One and four days later, angiogenesis represented by vascularized area, vessel density, and vessel junctions as well as HIF-1α and VEGF gene expression were evaluated. Furthermore, immune response (iNOS2, MMP-9, and MMP-13 via qPCR) was assessed and compared between ESWT- and non-ESWT-groups. At EDD-14, the vascularized area (+115% vs. +26%) and the increase in vessel junctions (+751% vs. +363%) were significantly higher in the ESWT-group. ESWT significantly increased MMP-9 gene expression at EDD-11 and significantly decreased MMP-13 gene expression at EDD-14 as compared to the controls. Using the CAM assay, an enhanced angiogenesis and neovascularization in CM after ESWT were observed. Furthermore, ESWT could reduce the inflammatory activity after a latency of four days.

Red and Yellow Injectable Platelet-Rich Fibrin Demonstrated Differential Effects on Periodontal Ligament Stem Cell Proliferation, Migration, and Osteogenic Differentiation

The biological benefits of using two fractions derived from injectable platelet-rich fibrin (i-PRF) in bone regeneration remain unclear. Thus, the current study examined two fractionation protocols producing yellow i-PRF and red i-PRF on periodontal ligament stem cells (PDLSCs). The i-PRF samples from five donors were harvested from two different levels, with and without a buffy coat layer, to obtain red and yellow i-PRF, respectively. The PDLSCs were isolated and characterized before their experimental use. The culture medium in each assay was loaded with 20% of the conditioned medium containing the factors released from the red and yellow i-PRF. Cell proliferation and cell migration were determined with an MTT and trans-well assay, respectively. Osteogenic differentiation was investigated using alkaline phosphatase and Alizarin red staining. The efficiency of both i-PRFs was statistically compared. We found that the factors released from the red i-PRF had a greater effect on cell proliferation and cell migration. Moreover, the factors released from the yellow i-PRF stimulated PDLSC osteogenic differentiation earlier compared with the red i-PRF. These data suggest that the red i-PRF might be suitable for using in bone regeneration because it induced the mobilization and growth of bone regenerative cells without inducing premature mineralization.

Collagen membranes of dermal and pericardial origin-In vivo evolvement of vascularization over time

Aim of the study was to compare the evolvement of vascularization over time of collagen membranes (CMs) of dermal and pericardial origin in an in vivo animal study. Twenty-eight mice underwent implantation of three commercially available CM derived from porcine dermis (homogenous structure: CM1 (Control 1) and bilayer structure: CM2 [Control 2]), from porcine pericardium (CM3; Test 1) as well as CM3 sprayed with silica-enhanced nanostructured hydroxyapatite (CM4, Test 2). After 3, 6, 9, and 12 days, intravital fluorescence microscopy was conducted for determination of capillary diameter, density, flow, and length. At Day 12, samples were examined immunohistologically for expression of fibroblast growth factor receptor 4 (FGFR4), CD11b, CD68, αSMA, and CD34. In all CM, intravital fluorescence microscopy over time showed increasing values for all parameters with the highest levels in CM4 and the lowest values in CM1. Significant lower amounts of FGFR4, CD11b, and CD68 were detected in CM4 when compared to CM2 (p < .05). In contrast to CM3, lower values of αSMA and higher numbers of CD34 positive-marked vessels were observed in CM4 (p < .05). In conclusion, dermal bilayer as well as pericardial CM seem to have a higher vascularization rate than dermal homogenous CM. Additional coating of pericardial CM with a silica-enhanced hydroxyapatite increases the speed of vascularization as well as biological remodeling processes.