Regenerative potential of leucocyte- and platelet-rich fibrin. Part B: sinus floor elevation, alveolar ridge preservation and implant therapy. A systematic review

Impact of platelet-rich fibrin derivatives on patient morbidity and quality of life in palatal donor sites following free gingival graft surgery: a randomized clinical trial

OBJECTIVES

Platelet concentrates are biomaterials with significant potential in tissue regeneration, functioning as scaffolds with greater leukocyte inclusion and a flexible fibrin mesh. However these concentrates have different preparation methods and biological properties. The objective of this clinical investigation was to evaluate the effects of utilizing platelet-rich fibrin (PRF) materials (L-PRF and A-PRF) as a palatal bandage following free gingival graft (FGG) on patients' morbidity and oral health-related quality of life.

MATERIALS AND METHODS

Thirty-nine participants received FGG to promote keratinized tissue and treat gingival recession. Participants were randomly assigned to L-PRF, A-PRF, and control groups, with 13 participants in each. They used a visual analog scale (VAS) to rate their pain, analgesic medication use, dietary changes, discomfort, and bleeding at 1-7 days, 14 days and 1 month during the healing process. Patients' quality of life was assessed using the Oral Health Impact Profile (OHIP-14) at baseline, 1-7 days, 14 days, 1 month, and 6 months.

RESULTS

There was no difference in anxiety levels between the all groups. (p > 0.05). The control group had higher OHIP-14 total scores than the other groups, but the differences were not statistically significant, especially in the first seven days (p > 0.05). In addition, the PRF groups showed an improvement in quality of life after 14 days, 1 month, and 6 months (p < 0.05). Patients' pain and suffering decreased with healing. The control group took more postoperative analgesics than PRF groups. In addition, there was a significant decrease in patient complaints about medicine intake, bleeding, pain, perceived sensitivity, and dietary modifications in all groups during follow-up.

CONCLUSIONS

PRF palatal bandages may improve patient's quality of life, donor site healing, postoperative pain and morbidity.

CLINICAL RELEVANCE

This study found that preserving the palate in FGG and employing PRF materials that speed palate healing reduce discomfort and morbidity.

Efficacy of autologous platelet concentrate products for alveolar preservation: A meta-analysis

PURPOSE

The purpose of the study was to systematically evaluate the efficacy of autologous platelet concentrate products in the preservation of the alveolar ridge after tooth extraction through meta-analysis and provide a theoretical basis for the clinical application of autologous platelet concentrates to reduce alveolar bone resorption.

METHODS

This study conducted a meta-analysis of clinical trials between 2013 and 2023, focusing on autologous platelet concentrate products (e.g., PRP, PRF, CGF, and PRCF) used for alveolar ridge preservation after tooth extraction. The analysis included 122 articles and 371 extraction sockets. All statistical analyses were performed using Review Manager version 5.4.

RESULTS

Results indicate that these platelet concentrates effectively reduced changes in horizontal width 1 mm below the alveolar crest and vertical socket height. They also promoted a higher percentage of new bone formation in extraction sockets compared with control groups. However, they did not significantly prevent horizontal bone resorption at 3 and 5 mm below the alveolar crest.

CONCLUSION

In conclusion, autologous platelet concentrates are useful for alveolar ridge preservation, but larger clinical studies are needed to confirm these findings due to the relatively small sample size in this study.

Efficacy of Platelet-Rich Fibrin in Preserving Alveolar Ridge Volume and Reducing Postoperative Pain in Site Preservation of Post-Extracted Sockets

Background and Objectives: In socket preservation, the goal is to minimize bone resorption after tooth extraction to maintain the volume and contour of the alveolar ridge. The use of PRF in post extraction sites may reduce ridge resorption by encouraging the growth of new bone and acting as a scaffold for tissue. In addition, PRF may enhance healing and minimize postoperative pain. The aim of this study was to evaluate the effectiveness of platelet-rich fibrin (PRF) in maintaining the ridges' dimensions at the extraction site, in the maxilla and mandible, as well as its impact on post-extraction discomfort. Methods: The study was conducted on 60 patients presenting for extraction of posterior teeth and was randomly divided into three groups: group I PRF (n = 20), group II PRF + collagen (n = 20), and group III control (n = 20). Sockets were filled with PRF (group I) and PRF + collagen (group II). At baseline and follow-up after 3 months, CBCT was used to assess the bone dimensions. The postoperative pain evaluations were performed at 24 h, 3 days, and 7 days after the tooth extraction. The pain rate was evaluated using a numerical rating scale from the British Pain Society. Results: The study examined the effects of platelet-rich fibrin (PRF) and PRF combined with collagen on the height and width of the ridges, as well as the pain experienced by the patients following alveolar ridge preservation surgery. ANOVA and t-tests were used to evaluate and compare the ridge dimensions. Comparing the results to the control group, there were no significant differences in the height or width of the ridges. However, both the PRF and PRF + Collaplug® treatments effectively reduced the short-term postoperative pain. Conclusions: The study findings suggest that platelet-rich fibrin (PRF) and PRF combined with collagen do not exert significant effects on ridge width and height compared to the standard treatment following alveolar ridge preservation. However, it is noteworthy that both the PRF and PRF + collagen treatments demonstrated efficacy in reducing postoperative pain in the short term, offering a potential advantage over standard treatment protocols.

The effect of platelet-rich fibrin (PRF) versus freeze-dried bone allograft (FDBA) used in alveolar ridge preservation on the peri-implant soft and hard tissues: a randomized clinical trial

BACKGROUND

The effectiveness of alveolar ridge preservation on bone regeneration and tissue healing has been thoroughly documented in the literature. This study aimed to evaluate the peri-implant soft and hard tissue changes after alveolar ridge preservation using either platelet-rich fibrin (PRF) or freeze-dried bone allograft (FDBA) over a 12-month period following the prosthetic loading of implants.

METHODS

In this randomized clinical trial, 40 individuals were recruited for alveolar ridge preservation using (1) FDBA or (2) PRF in incisal/premolar areas. At two follow-up sessions (six- and 12-months post-implant insertion), radiographic imaging and clinical examinations assessed marginal bone loss and soft tissue factors, including gingival recession and bleeding on probing. The differences between study groups were analyzed using Generalized estimating Equations, the Binary logistic regression model, and Cochran's Q test.

RESULTS

There was a statistically significant difference regarding gingival recession at both follow-up evaluations; values in the PRF group were considerably lower compared to the FDBA group (p < 0.05). The mean values for vertical marginal bone loss and bleeding on probing showed no significant differences between the two study groups (p > 0.05).

CONCLUSIONS

Except for gingival recession, applying PRF yielded comparable clinical results to FDBA after one year of implant loading and could be recommended as a potential biomaterial for alveolar ridge preservation following tooth extractions.

CLINICAL TRIAL REGISTRATION

The research protocol was registered in the Protocol Registration and Results System on 13/08/2021, available at https://clinicaltrials.gov/ (NCT05005377).

Comparison of histologic and radiographic changes of sockets grafted with LPRF and sockets without intervention after tooth extraction

OBJECTIVES

After tooth extraction, marked resorption occurs in extraction socket walls, leading to functional and esthetic problems in that area. One of the methods introduced to reduce this resorption is the use of platelet derivatives. This study aimed to evaluate the effects of leukocyte and platelet-rich fibrin (L-PRF) on the changes following tooth extraction.

MATERIALS AND METHODS

The participants were 24 patients who needed to replace at least one single-rooted tooth with an implant. They were randomly divided into test and control groups. After the tooth extraction, the sockets in the test group received LPRF clots, while in the control group, the sockets were left free of any interventions. CBCT scans were obtained from the extraction site both immediately after the tooth extraction and 8 weeks later. The histologic biopsy was also obtained while the implant site was being prepared 8 weeks after the extraction.

RESULTS

The average vertical bone loss in the buccal crest was not significantly different between the two groups (1.67 ± 1.67 in the test group and 2.3 ± 1.36 in the control group; mean difference =  - 0.36, 95% CI: - 1.65-0.93, p-value = 0.57). Nor was the difference in resorption of the palatal wall (mean difference =  - 0.19, 95% CI: - 1.51.12, p-value = 0.76). The mean ridge width resorption in 25% of the coronal aspect of sockets was also measured in the test (1.30 ± 0.66) and control group (0.58 ± 0.95) (mean difference = 0.73, 95% CI: 0.03-1.42, p-value = 0.04). The new bone formation in histologic view was not statistically different between groups (p-value = 0.15).

CONCLUSION

The LPRF neither reduces the rate of ridge resorption in vertical or horizontal dimensions of extraction sockets nor induces more new bone formation.

CLINICAL RELEVANCE

This study helps dentists choose the appropriate material for ridge preservation.

L-PRF Secretome from Both Smokers/Nonsmokers Stimulates Angiogenesis and Osteoblast Differentiation In Vitro

Leukocyte and Platelet-Rich Fibrin (L-PRF) is part of the second generation of platelet-concentrates. L-PRF derived from nonsmokers has been used in surgical procedures, with its beneficial effects in wound healing being proven to stimulate biological activities such as cell proliferation, angiogenesis, and differentiation. Cigarette smoking exerts detrimental effects on tissue healing and is associated with post-surgical complications; however, evidence about the biological effects of L-PRF derived from smokers is limited. This study evaluated the impact of L-PRF secretome (LPRFS) derived from smokers and nonsmokers on angiogenesis and osteoblast differentiation. LPRFS was obtained by submerging L-PRF membranes derived from smokers or nonsmokers in culture media and was used to treat endothelial cells (HUVEC) or SaOs-2 cells. Angiogenesis was evaluated by tubule formation assay, while osteoblast differentiation was observed by alkaline phosphatase and osterix protein levels, as well as in vitro mineralization. LPRFS treatments increased angiogenesis, alkaline phosphatase, and osterix levels. Treatment with 50% of LPRFS derived from smokers and nonsmokers in the presence of osteogenic factors stimulates in vitro mineralization significantly. Nevertheless, differences between LPRFS derived from smokers and nonsmokers were not found. Both LPRFS stimulated angiogenesis and osteoblast differentiation in vitro; however, clinical studies are required to determine the beneficial effect of LPRFS in smokers.

Effectiveness of Autologous Platelet Concentrates in the Sinus Lift Surgery: Findings from Systematic Reviews and Meta-Analyses

Maxillary sinus augmentation is one of the most predictable procedures for the rehabilitation of the posterior maxilla. The current overview aimed to summarize the findings provided by systematic reviews (SRs) and meta-analyses on the effectiveness of autologous platelet concentrates (APCs) in sinus lift and to assess the methodological quality of the included SRs. Three electronic databases have been explored. SRs and meta-analyses addressing the effectiveness of APCs in sinus lift technique were included. Clinical, radiographic and histomorphometric findings were considered for APCs as solely grafting materials and APCs in combination with biomaterials. Outcomes were implant survival rate (ISR), implant stability (IS), implant failure (IF), postoperative complications, histomorphometric findings, radiographic bone gain, bone volume and bone density. The methodological quality of the included SRs was assessed using the updated version of "A Measurement Tool to Assess Systematic Review" (AMSTAR-2). Thirty SRs were included. The methodological quality of the included reviews ranged from critically low (3 studies) to high (9 studies). The included SRs showed favorable clinical outcomes, short-term new bone formation and no biological complications when APCs were used both as solely graft material or in combination with other biomaterials. However, no significant additional effects in the long-term period were observed. APCs did not add any further positive effects compared to the physiological healing derived by the natural blood clot. The current overview of SRs highlighted the need for high-quality SRs evaluating the role of APCs in sinus lift though network meta-analyses, in order to identify the most powerful material for sinus lift augmentation. The use of APCs improves the healing of soft tissues and the postoperative quality of life in the short-term period. Thus, its application can be recommended.

Delayed centrifugation weakens the in vitro biological properties of platelet-rich fibrin membranes

OBJECTIVE

To investigate how delayed blood centrifugation affects the composition of the resultant platelet rich fibrin membrane (PRF, a concentrated growth factor preparation) and its biological effects towards gingival fibroblasts.

MATERIALS AND METHODS

Blood samples were collected from 18 healthy individuals and centrifuged immediately (T-0), or after a 1-6-minute delay (T-1-6, respectively), to generate PRF. Each PRF membrane was weighed. T-0 and T-6 membranes were incubated for 48 h in cell culture medium at 37 °C to create PRF "releasates" (soluble factors released from the PRF). Human gingival fibroblasts were incubated for 48 h with or without the releasates, followed by RNA isolation and real-time polymerase chain reaction to measure expression of select genes associated with granulation tissue formation, angiogenesis and wound contraction. Additional T-0 and T-6 membranes were used for visualization of leucocyte nuclei and platelets by immunostaining.

RESULTS

Immediate centrifugation (T-0) resulted in the largest membranes, T-6 membranes being on average 29% smaller. Leucocytes and platelets were significantly more abundant in T-0 than in T-6 samples. Majority of the fibroblast genes studied were consistently either upregulated or downregulated by the T-0 PRF releasates. However, centrifugation after a 6-minute delay significantly weakened the fibroblast responses.

CONCLUSIONS

Delayed centrifugation resulted in smaller PRF membranes with fewer leucocytes and platelets and also significantly reduced on the expression of a set of healing-related gingival fibroblast genes.

CLINICAL RELEVANCE

The higher expression of wound healing-related genes in gingival fibroblasts by the immediately-centrifuged PRF membranes may increase their biological properties in clinical use.

The use of mesenchymal stromal cell secretome to enhance guided bone regeneration in comparison with leukocyte and platelet-rich fibrin

OBJECTIVES

Secretomes of mesenchymal stromal cells (MSC) represent a novel strategy for growth-factor delivery for tissue regeneration. The objective of this study was to compare the efficacy of adjunctive use of conditioned media of bone-marrow MSC (MSC-CM) with collagen barrier membranes vs. adjunctive use of conditioned media of leukocyte- and platelet-rich fibrin (PRF-CM), a current growth-factor therapy, for guided bone regeneration (GBR).

METHODS

MSC-CM and PRF-CM prepared from healthy human donors were subjected to proteomic analysis using mass spectrometry and multiplex immunoassay. Collagen membranes functionalized with MSC-CM or PRF-CM were applied on critical-size rat calvaria defects and new bone formation was assessed via three-dimensional (3D) micro-CT analysis of total defect volume (2 and 4 weeks) and 2D histomorphometric analysis of central defect regions (4 weeks).

RESULTS

While both MSC-CM and PRF-CM revealed several bone-related proteins, differentially expressed proteins, especially extracellular matrix components, were increased in MSC-CM. In rat calvaria defects, micro-CT revealed greater total bone coverage in the MSC-CM group after 2 and 4 weeks. Histologically, both groups showed a combination of regular new bone and 'hybrid' new bone, which was formed within the membrane compartment and characterized by incorporation of mineralized collagen fibers. Histomorphometry in central defect sections revealed greater hybrid bone area in the MSC-CM group, while the total new bone area was similar between groups.

CONCLUSION

Based on the in vitro and in vivo investigations herein, functionalization of membranes with MSC-CM represents a promising strategy to enhance GBR.

Leukocyte- and Platelet-Rich Fibrin (L-PRF) Obtained from Smokers and Nonsmokers Shows a Similar Uniaxial Tensile Response In Vitro

We evaluated and compared the biomechanical properties of Leukocyte-and Platelet Rich Fibrin L-PRF clots and membranes derived from smoker and nonsmoker donors. Twenty venous-blood donors (aged 18 to 50 years) were included after signing informed consent forms. L-PRF clots were analyzed and then compressed to obtain L-PRF membranes. L-PRF clot and membrane samples were tested in quasi-static uniaxial tension and the stress-stretch response was registered and characterized. Furthermore, scanning electron microscope representative images were taken to see the fibrin structure from both groups. The analysis of stress-stretch curves allowed us to evaluate the statistical significance in differences between smoker and nonsmoker groups. L-PRF membranes showed a stiffer response and higher tensile strength when compared to L-PRF clots. However, no statistically significant differences were found between samples from smokers and nonsmokers. With the limitations of our in vitro study, we can suggest that the tensile properties of L-PRF clots and membranes from the blood of smokers and nonsmokers are similar. More studies are necessary to fully characterize the effect of smoking on the biomechanical behavior of this platelet concentrate, to further encourage its use as an alternative to promote wound healing in smokers.

Antimicrobial Effects of Platelet-Rich Plasma and Platelet-Rich Fibrin: A Scoping Review

Platelet-rich plasma (PRP), derived from the centrifugation and subsequent separation of whole blood, results in an unusually high concentration of platelets. A newer form of platelet concentrate, platelet-rich fibrin (PRF), has also been developed. There has been significant research into the therapeutic effects of PRP, particularly in enhancing wound healing and preventing infections in surgical wounds. This scoping review aims to thoroughly evaluate preclinical and clinical evidence regarding the antimicrobial effects of PRP and PRF. In conducting this review, 612 records were examined, and 36 articles were selected for inclusion. The studies reviewed include preclinical research, such as in-vitro and in-vivo studies, and clinical trials involving human participants. The current clinical evidence suggests a notable trend towards the antimicrobial capabilities of PRP and PRF, underscoring their potential benefits in treating wounds. The application of PRP and PRF in wound management shows encouraging outcomes, but further investigation is needed to optimize their use as antimicrobial agents. Additional research, particularly randomized controlled trials, is essential to substantiate their antimicrobial effectiveness in specific diseases and types of wounds, considering their potential impact on clinical results.

Effect of thermal manipulation on the biological and mechanical characteristics of horizontal platelet rich fibrin membranes

BACKGROUD

Regardless of application scenarios, proper mechanical characteristics and degradation properties are prerequisites for horizontal platelet rich fibrin (H-PRF) to manifest its ability. Among the methods used to modify PRF, thermal manipulation is promising as it is easy to handle without adding extra additives. Yet there is no consensus on optimal temperature treatment. This study aimed to investigate the effects of heating on the biological and mechanical characteristics of H-PRF and explore the optimum heating temperature for H-PRF thermal treatment.

METHODS

We employed a series of temperature gradients, room temperature, 50℃, 75℃, 90℃, 105℃. The microstructure and the mechanical properties were recorded by Scanning Electron Microscope (SEM) and tensile strength tests respectively. The degradation rate of H-PRF membranes was examined by digestion assay with plasmin and trypsin. The viability of cells within H-PRF membranes and the proliferation of osteoblasts cultured with extracts from different H-PRF groups was evaluated using CCK-8 assays.

RESULTS

Compared with the nonheated group, overheated manipulation beyond 90℃ can significantly prolong the degradation properties for up to 3 to 4 weeks and enhance the mass stress of H-PRF membranes. A high-temperature treatment of 105℃ accompanied by the cell activity beneath H-PRF reduced more than half, and thus, the biological effect on human osteoblasts (hFOBs) also reduced dramatically.

CONCLUSIONS

High thermal manipulation can prolong the degradation properties and enhance the mechanical properties of PRF membranes accompanied by the loss of biological effect.

Efficacy of concentrated growth factor (CGF) in the surgical treatment of oral diseases: a systematic review and meta-analysis

BACKGROUND

Concentrated growth factor (CGF), a new autologous platelet concentrate, has been widely investigated to the adjunctive treatment of oral diseases. This study aims to evaluate the efficacy of CGF in the surgical treatment of oral diseases.

METHODS

MEDLINE, Web of Science, Scopus, Cochrane, and EMBASE databases were searched up to July 2023. Only randomized clinical trials were included. The methodologic quality was evaluated by the Cochrane Risk of Bias Tool. RevMan 5.4 software was used for data analysis.

RESULTS

In the treatment of periodontal intrabony defects, bone graft combined with CGF was significantly superior to bone graft (P < 0.01), with mean intrabony defect depth reduction of 1.41 mm and mean clinical attachment level gain of 0.55 mm. In the regenerative surgery of furcation defects, the effect of CGF group was significantly better than control group (P < 0.0001), with mean probing depth reduction of 0.99 mm, vertical bone gain of 0.25 mm, and horizontal bone gain of 0.34 mm. CGF combined with coronally advanced flap (CAF) was more effective than CAF alone (mean keratinized tissue width increase of 0.41 mm, mean gingival thickness increase of 0.26 mm, P < 0.00001), but less effective than connective tissue graft (CTG) combined with CAF (mean root coverage difference of -15.1%, mean gingival thickness difference of -0.5 mm, P < 0.0001). In the alveolar ridge preservation, additional use of CGF reduced horizontal bone resorption by 1.41 mm and buccal vertical bone resorption by 1.01 mm compared to control group (P < 0.0001). The VAS score of CGF group was significantly lower than that of the control group at the 1st and 7th day after oral surgery (P < 0.0001).

CONCLUSIONS

CGF can exert a positive adjunctive effect for the regenerative surgery of periodontal intrabony defects, furcation defects, and alveolar ridge preservation procedure. CGF combined with CAF has a better therapeutic effect on gingival recession compared to CAF alone, although it is not as effective as CTG combined with CAF. CGF could promote postoperative healing and pain relief in oral surgery within a week. There is currently not enough evidence to support the clinical benefits of CGF in other oral surgeries.

Proteomic Analysis of Mesenchymal Stromal Cells Secretome in Comparison to Leukocyte- and Platelet-Rich Fibrin

Secretomes of mesenchymal stromal cells (MSCs) are emerging as a novel growth factor (GF)-based strategy for periodontal and bone regeneration. The objective of this study was to compare the secretome of human bone marrow MSC (BMSC) to that of leukocyte- and platelet-rich fibrin (L-PRF), an established GF-based therapy, in the context of wound healing and regeneration. Conditioned media from human BMSCs (BMSC-CM) and L-PRF (LPRF-CM) were subjected to quantitative proteomic analysis using liquid chromatography with tandem mass spectrometry. Global profiles, gene ontology (GO) categories, differentially expressed proteins (DEPs), and gene set enrichment (GSEA) were identified using bioinformatic methods. Concentrations of selected proteins were determined using a multiplex immunoassay. Among the proteins identified in BMSC-CM (2157 proteins) and LPRF-CM (1420 proteins), 1283 proteins were common. GO analysis revealed similarities between the groups in terms of biological processes (cellular organization, protein metabolism) and molecular functions (cellular/protein-binding). Notably, more DEPs were identified in BMSC-CM (n = 550) compared to LPRF-CM (n = 118); these included several key GF, cytokines, and extracellular matrix (ECM) proteins involved in wound healing. GSEA revealed enrichment of ECM (especially bone ECM)-related processes in BMSC-CM and immune-related processes in LPRF-CM. Similar trends for intergroup differences in protein detection were observed in the multiplex analysis. Thus, the secretome of BMSC is enriched for proteins/processes relevant for periodontal and bone regeneration. The in vivo efficacy of this therapy should be evaluated in future studies.

Bacterial exclusion and wound healing potential of horizontal platelet-rich fibrin (H-PRF) membranes when compared to 2 commercially available collagen membranes

OBJECTIVES

The aim of the present study was to compare the barrier function during bacterial invasion and wound healing properties of 3 commonly used membranes including horizontal platelet-rich fibrin (H-PRF) against two commercially available resorbable collagen membranes.

MATERIALS AND METHODS

H-PRF membranes were prepared by collecting venous blood from 3 healthy volunteers using a 700 g for 8-min centrifugation protocol followed by compression into membranes. To evaluate their barrier function, 3 groups (H-PRF membrane, collagen membrane A (Bio-Gide, Geistlich), collagen membrane B (Megreen, Shanxi Ruisheng Biotechnology Co) were placed between an inner chamber and outer chamber and inoculated with S. aureus. At 2 h, 24 h, and 48 h post-inoculation, cultures from the inner and outer chambers were assessed for bacterial CFUs. Then, scanning electron microscope (SEM) was utilized to visualized the morphological destruction by bacteria of the inner and outer surfaces of the membranes. To assess the wound healing properties of each membrane, leachates from each group were applied to human gingival fibroblasts (HGF) and a scratch assay was performed at 24 h and 48 h.

RESULTS

S. aureus showed a minimal bacterial attachment or invasion rate through either collagen membranes at 2 h post-inoculation, yet over time demonstrated rapid degradation, especially on the rougher surface. While PRF demonstrated higher number of CFUs after 2 h, no significant penetration/degradation of the H-PRF membranes was observed at 24 h and 48 h in the H-PRF group. Both collagen membranes demonstrated significant morphological changes 48 h post-bacterial innoculation, while minimal obvious morphological changes were observed in the H-PRF group. The wound healing assay also demonstrated significantly better wound closure rates in the H-PRF group.

CONCLUSION

H-PRF membranes exhibited better barrier function towards S. aureus over 2 days of innoculation and better wound healing ability when compared to two commercially available collagen membranes.

CLINICAL RELEVANCE

This study provides further evidence for the application of H-PRF membranes during guided bone regeneration by minimizing bacterial invasion. Furthermore, H-PRF membranes have significantly better ability to promote wound healing.

Leukocyte- and platelet-rich fibrin in endoscopic endonasal skull base reconstruction: study protocol for a multicenter prospective, parallel-group, single-blinded randomized controlled non-inferiority trial

BACKGROUND

Recent advances in endoscopic endonasal transsphenoidal approaches (EETA) for skull base lesions have resulted in a significant increase in extent and complexity of skull base defects, demanding more elaborate and novel reconstruction techniques to prevent cerebrospinal fluid (CSF) leakage and to improve healing. Currently, commercially available fibrin sealants are often used to reinforce the skull base reconstruction. However, problems have been reported regarding hypersensitivity reactions, efficacy, and costs. This trial aims to investigate autologous leukocyte- and platelet-rich fibrin (L-PRF) membranes as an alternative for commercially available fibrin glues in EETA-related skull base reconstruction reinforcement.

METHODS/DESIGN

This multicenter, prospective randomized controlled trial aims to demonstrate non-inferiority of L-PRF membranes compared to commercially available fibrin sealants in EETA cases (1) without intra-operative CSF-leak as dural or sellar floor closure reinforcement and (2) in EETA cases with intra-operative CSF-leak (or very large defects) in which a classic multilayer reconstruction has been made, as an additional sealing. The trial includes patients undergoing EETA in three different centers in Belgium. Patients are randomized in a 1:1 fashion comparing L-PRF with commercially available fibrin sealants. The primary endpoint is postoperative CSF leakage. Secondary endpoints are identification of risk factors for reconstruction failure, assessment of rhinological symptoms, and interference with postoperative imaging. Additionally, a cost-effectiveness analysis is performed.

DISCUSSION

With this trial, we will evaluate the safety and efficacy of L-PRF compared to commercially available fibrin sealants.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03910374. Registered on 10 April 2019.

The Effectiveness of the Addition of Platelet-Rich Fibrin to Bovine Xenografts in Sinus and Bone Ridge Augmentation: A Systematic Review

Dental implants sometimes need bone augmentation to recreate an adequate bone height and volume. Numerous bone augmentation techniques have been described, and, currently, the most commonly used bone graft procedure is xenografts with deproteinized bovine bone mineral (DBBM). The addition of platelet-rich fibrin (PRF) to DBBM has already shown better performance than DBBM alone in restoring intrabony periodontal defects, but the role of PRF in preimplantation bone grafts is still not clear. The objective of this systematic review was to evaluate the efficacy of the adjunction of PRF or L-PRF to DBBM in bone ridge augmentation procedures. Clinical randomized controlled studies using PRF associated with DBBM were included. In April 2023, three electronic databases (PubMed, Cochrane, and Web of Science) were searched. The search strategy was performed according to PRISMA guidelines. The risk of bias assessments were performed using the Cochrane Collaboration tool. A total of seven articles were included and analyzed. The results show no statistically significant effect of PRF added to DBBM compared to DBBM alone in the sinus lift procedure but do show an effect in the reduction in bone graft resorption in one study of mandibular guided bone regeneration.

Evaluation of Implant Surface Modification with Nanohydroxyapatite Associated with the Use of L-PRF: In Vivo Study in Rats

Leukocyte-platelet-rich fibrin (L-PRF) contains growth factors that stimulate bone regeneration. This study evaluated the bone repair in a tibia rat model around two implant surfaces in combination or not with L-PRF by assessing microtomographic and histomorphometric parameters. A total of 48 female rats were used in the study, in which 24 received implants with two types of surface treatments (dual acid etched-DAE or nanohydroxyapatite-nanoHA), and the other 24 received the same mini implants with L-PRF, which was collected by cardiac puncture, centrifugated, and inserted in the bone bed. The animals were euthanized 7 and 30 days after implant placement, and the retrieved samples were prepared for microtomographic and histomorphometric (bone-to-implant contact-BIC; and Bone Area Fraction Occupancy-BAFO) analyses. The adhesion of the nanoHA surface onto the implant surface was investigated by insertion and removal in simulated bone medium (Sawbones). The adhesion evaluation revealed that the loss of nanoHA after this procedure (as measured with SEM) from the implant surface was less than 1%. Overall, the nanoHA surface presented more bone in contact and in proximity to the implant, a higher bone surface/tissue volume fraction, a higher number of bone trabeculae, as well as trabecular separation relative to the DAE surface. Such results were more evident when the nanoHA surface was combined with L-PRF and after 30 days in vivo. The nanoHA surface presented higher BAFO when compared to DAE, with or without association with L-PRF. Therefore, implants with a nanoHA surface potentially benefit from the association to L-PRF.

Cone-Beam Computed Tomography and Histological Findings for Socket Preservation Techniques Using Different Grafting Materials: A Systematic Review

OBJECTIVE

Socket preservation techniques have been used to maintain the ridge dimension following tooth extraction. The materials used influence the quality and quantity of newly formed bone. Therefore, the aim of this article was to systematically review the literature reporting both histological and radiographic outcomes of socket preservation techniques after tooth extraction in human subjects.

MATERIAL AND METHOD

A systematic electronic search was performed in the electronic databases. English language clinical studies that were published between 2017 and 2022 and included both histological and radiographic findings for the test and control groups. Our primary search produced 848 articles, and of these, 215 were duplicate studies. A total of 72 articles were then eligible for full-text reading.

RESULTS

The review included eight studies that met its inclusion criteria. Three outcomes were compared in the included studies. The percentage of newly formed bone ranged from 21.34 ± 9.14% to more than 50% of new bone formation. The materials that showed more than 50% of newly formed bone formation were demineralized dentin graft, platelet-rich fibrin, freeze-dried bone allograft, corticocancellous porcine, and autogenous bone. Four Studies did not report the percentage of the residual graft materials, while those who reported showed a variable range of a minimum 1.5% to more than 25%. One study did not report the changes in horizontal width at the follow-up period, while other studies ranged from 0.6 mm to 10 mm.

CONCLUSION

Socket preservation represents an efficient technique to preserve the ridge contour with satisfactory newly formed bone in the augmented site and maintaining the vertical and horizontal dimensions of the ridge.

Efficacy of the application of leukocyte and platelet-rich fibrin (L-PRF) on alveolar ridge preservation. A randomized controlled clinical trial

INTRODUCTION

Alveolar ridge preservation (ARP) is a well-defined treatment performed to reduce bone dimensional changes occurring during the healing of post-extraction sockets to allow for adequate implant placement. Leukocyte and platelet-rich fibrin (L-PRF) has been showing to potentially promote bone and tissue regeneration during wound healing. Therefore, the aim of this study is to evaluate its efficacy for ARP when applied to fresh extraction sockets, in comparison with spontaneous healing.

MATERIALS AND METHODS

Twenty-seven patients with hopeless non-molar teeth were treated. After randomization, fresh extraction sockets were either filled with L-PRF or allowed to heal spontaneously. CBCTs and intraoral scans were obtained immediately after extraction and at 4 months. Through superimposition of the obtained images, changes in the horizontal ridge width, height, buccal volume, and ridge contour changes were measured, as well as patient-reported outcome measures (PROM's).

RESULTS

The ridge dimensions changed similarly in both groups. Although less reduction occurred in the test group at 1 mm from the bone crest, differences were not statistically significant (p > 0.05). Application of L-PRF did not prevent reductions of ridge contours, neither in the linear vertical aspect nor in volumetric changes. There were no differences between groups in the need for bone regeneration when placing implants. Patients in both groups reported similar outcomes in terms of bleeding, pain, inflammation, and function at 1 and 4 weeks postoperatively.

CONCLUSION

Alveolar preservation with L-PRF neither minimized bone resorption occurring after tooth extraction in non-molar sites nor reduced the need for bone regeneration when placing implants. Furthermore, its use did not improve PROM's.

Leukocyte- and platelet-rich fibrin in cranial surgery: study protocol for a prospective, parallel-group, single-blinded randomized controlled non-inferiority trial {1}

BACKGROUND

CSF leakage is a major complication after cranial surgery, thus, adequate dural closure must be performed. Commercially available fibrin sealants are currently considered the gold standard for dural closure, but problems have been reported regarding safety, efficacy, and costs. This trial aims to investigate autologous leukocyte- and platelet-rich fibrin (L-PRF) as an alternative to commercially available fibrin sealants.

METHODS/DESIGN

This single-blinded, prospective randomized controlled interventional trial aims to demonstrate the non-inferiority of L-PRF compared to commercially available fibrin sealants for dural closure. This trial will include patients undergoing cranial neurosurgery (supratentorial and infratentorial) with intentional opening of the dura. Patients are randomized in a 1:1 fashion comparing L-PRF to commercially available fibrin sealants. The primary endpoint is postoperative CSF leakage within 12 weeks after surgery. Secondary endpoints are complications such as bleeding or wound infections. Additionally, a cost-effectiveness analysis is performed.

DISCUSSION

With this trial, we will evaluate the safety and efficiency of L-PRF compared to commercially available fibrin sealants.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03812120. Registered on 22 January 2019.

Platelet-rich fibrin combined with a particulate bone substitute versus guided bone regeneration in the damaged extraction socket: An in vivo study

AIM

It has been proposed that platelet-rich fibrin (PRF) can be used to support bone regeneration during alveolar ridge augmentation. The aim of this study was to determine whether an approach utilizing PRF provides similar performance to the established guided bone regeneration (GBR) procedure.

MATERIALS AND METHODS

Two-wall defects were surgically created in beagle dogs and treated in three experimental groups: (i) a sticky bone (SB) substitute prepared using liquid PRF and deproteinized porcine bone mineral (DPBM); (ii) SB covered with solid PRF compressed into a membrane; and (iii) GBR performed using DPBM covered by a collagen membrane. Quantitative reverse-transcription polymerase chain reaction was applied to the specimen after 1 week of healing, and microcomputed tomography (micro-CT) and histological outcomes were analysed after 8 weeks of healing.

RESULTS

Compared with GBR, PRF resulted in a moderate increase in the expression levels of osteoblast and osteoclast markers, osteocalcin, and calcitonin receptor. Moreover, PRF modestly increased angiogenesis and the inflammation markers vascular endothelial growth factor (VEGF) and IL-6. Micro-CT and histological analyses confirmed the expected increased alveolar ridge area, with no significant differences between the three groups. Consistently, graft consolidation, as indicated by new bone formation at the defect site, did not differ significantly between groups.

CONCLUSIONS

The present results demonstrate that PRF-based approaches perform comparably to the established GBR procedure in terms of the consolidation of DPBM in two-wall alveolar defects.

Smoking habits do not affect biological responses induced by leucocyte and platelet-rich fibrin in periodontal ligament cells

BACKGROUND AND OBJECTIVE

Leucocyte- and platelet-rich fibrin has been developed to stimulate wound healing response. However, it is currently unknown whether smoking affects the biological responses elicited by leucocyte- and platelet-rich fibrin on periodontal ligament-derived mesenchymal stromal cells. This study analyzes the kinetics of biomolecule release from leucocyte- and platelet-rich fibrin derived from smokers and nonsmokers and their effect on periodontal ligament cell proliferation and migration as essential biological activities during wound healing.

METHODS

Biomolecules present in leucocyte- and platelet-rich fibrin exudates and conditioned media collected from smokers and nonsmokers were analyzed by Luminex arrays. Periodontal ligament-derived mesenchymal stromal cell obtained from one nonsmoker were treated with leucocyte- and platelet-rich fibrin exudates or leucocyte- and platelet-rich fibrin conditioned media derived from both smokers and nonsmokers. The parameters evaluated included cell proliferation, determined by Ki67 immunostaining and migration assessed using transwell assays. Also, cells were treated with nicotine in the presence of fetal bovine serum 10% or leucocyte- and platelet-rich fibrin conditioned media.

RESULTS

A similar biomolecular profile was detected in leucocyte- and platelet-rich fibrin exudates and leucocyte- and platelet-rich fibrin conditioned media from smokers and nonsmokers, stimulating (periodontal ligament-derived mesenchymal stromal cell) proliferation, and migration to a comparable degree. Nicotine reduced cell proliferation and migration of periodontal cells; however, this effect was recovered in the presence of leucocyte- and platelet-rich fibrin conditioned media.

CONCLUSION

Leucocyte- and platelet-rich fibrin derived from smokers could be an autologous source of biomolecules to stimulate cell biological activities involved in wound healing in smokers who have difficulties in ceasing this habit. Clinical trials are required to evaluate the impact of leucocyte- and platelet-rich fibrin on healing responses in smokers.

Efficacy of biologics for the treatment of periodontal infrabony defects: An American Academy of Periodontology best evidence systematic review and network meta-analysis

BACKGROUND

A large variety of biomaterials, biologics and membranes have been utilized in the past 40 years for the regenerative treatment of periodontal infrabony defects. Biologic agents have progressively gained popularity among clinicians and are routinely used for periodontal regeneration. In alignment with the goals of the American Academy of Periodontology (AAP) Best Evidence Consensus (BEC) on the use of biologic mediators in contemporary clinical practice, the aim of this sytematic review was to evaluate the effect of biologic agents, specifically autogenous blood-dervied products (ABPs), enamel matrix derivative (EMD) and recombinant human platelet-derived growth factor-BB (rhPDGF-BB), on the regenerative outcomes of infrabony defects.

METHODS

A detailed systematic search was conducted to identify eligible randomized control trials (RCTs) reporting the outcomes of periodontal regenerative therapy using biologics for the treatment of infrabony defects. A frequentist mixed-modeling approach to network meta-analysis (NMA), characterized by the assessment of three individual components for the treatment of an infrabony defect (the bone graft material [BG], the biologic agent, the application of a barrier membrane) was performed to evaluate and compare the relative efficacy of the different components, on the outcomes of different therapeutic modalities of periodontal regeneration.

RESULTS

A total of 153 eligible RCTs were included, with 150 studies contributing to the NMA. The quantitative analysis showed that the addition of biologic agents to bone graft significantly improves the clinical and radiographic outcomes, as compared to BG and flap procedures alone. Barrier membranes enhanced the regenerative outcomes of BG but did not provide further benefits in combination with biologics. The type of BG (autogenous, allogeneic, xenogeneic or alloplastic) and the biologic agent (EMD, platelet-rich fibrin [PRF], platelet-rich plasma [PRP] or rhPDGF-BB) played a significant role on the final outcomes of infrabony defects. Allogeneic and xenogeneic BGs exhibited statistically significantly superior clinical gain than synthetic and autogenous BGs (p < 0.05 in all the comparisons), while rhPDGF-BB and PRF demonstrated significantly higher stability of the gingival margin (p < 0.01) and radiographic bone fill/gain (p < 0.05), together with greater, although not statistically significant, clinical attachment level gain and pocket depth reduction, than EMD and PRP. Overall, rhPDGF-BB exhibited the largest effect size for most parameters, including clinical attachment level gain, pocket depth reduction, less gingival recession and radiographic linear bone gain. Considering the relatively high number of trials presenting an unclear or high risk of bias, the strength of recommendation supporting the use of PRP was judged weak, while the recommendation for EMD, PRF and rhPDGF-BB was deemed in favor.

CONCLUSIONS

Biologics enhance the outcomes of periodontal regenerative therapy. Combination therapies involving BGs + biologics or BGs + barrier membrane demonstrated to be superior to monotherapies. The choice of the type of BG and biologic agent seems to have significant impact on the clinical and radiographic outcomes of infrabony defects.

Effect of leukocyte-platelet-rich fibrin in bone healing around dental implants placed in conventional and wide osteotomy sites: A pre-clinical study

Leukocyte-platelet-rich fibrin (L-PRF) has been suggested for gap management for immediate implant placement when the distance is greater than 2 mm. However, there remains a paucity in hierarchically designed research to support this application. The present study aimed to evaluate the effect of L-PRF on the osseointegration parameters of dental implants placed after conventional osteotomy of surgically created bone defects that simulate post extraction sockets in a canine model after 3, 6, and 12 weeks in vivo. Eighty dental implants (Intra-Lock, Boca Raton, FL) were placed in the radius of 13 beagle dogs. The experiment consisted of 4 groups (n = 20 implants/group): 1) Regular osteotomy (Reg n/L-PRF); 2) Regular osteotomy and implant placement with L-PRF membrane (Reg L-PRF); 3) Wide osteotomy with no gap management performed, where an osteotomy/bony defect (6 mm of diameter and ~5 mm deep) was created to simulate immediate implant placement in post-extraction sockets, and the gap was left for spontaneous healing (Wide nL-PRF); and 4) Wide osteotomy with L-PRF gap management (Wide L-PRF). L-PRF membranes were obtained by blood drawn from each subject and centrifuged at 2700 rpm (408 RCF-clot) for 12 min. In the experimental groups where L-PRF was utilized, the membrane was inserted into the osteotomy site prior to implant placement. Six dogs had implants placed in the radius for 3 weeks; and 7 dogs had implants placed in the left radius for 6 weeks and in the right radius for 12 weeks. At the corresponding experimental time points, samples were harvested, and subjected to histological processing for qualitative and quantitative analyses, via bone-to-implant contact (BIC) and bone-area-fraction occupancy (BAFO). Qualitative analysis demonstrated increased amounts of bone formation around the implant and within the healing chambers over time for all groups. While comparable histological features were observed for both Reg groups (L-PRF and nL-PRF), the gap management performed in Wide L-PRF group resulted in effective gap filling with improved bone growth in close proximity to the implant surface. Quantitative analyses of BIC and BAFO yielded higher values for both variables at 3 weeks for Wide L-PRF (~38% and ~56% respectively) compared to Wide nL-PRF (~20% for BIC and BAFO) (p < .03). No statistical differences were detected between Wide groups at 6 and 12 weeks, neither between Reg groups, independent of the association with or without the L-PRF membrane at all healing times. L-PRF placed within wide osteotomies, prior to implant placement, resulted in increased early bone formation compared to unfilled wide osteotomies at the early healing time (3 weeks in vivo).

Effect of platelet concentrate prepared by different methods on the healing of full-thickness skin defects

BACKGROUND

Platelet-rich plasma and concentrated growth factors have been widely utilized in tissue regeneration. However, very few studies have focused on comparing the merits of these two materials in skin repair.

AIMS

We aim to compare the wound healing effects of four platelet concentrates.

METHODS

Auto-platelet-rich plasma, artificial platelet-rich plasma, concentrated growth factors in a liquid phase, and a gel phase were prepared, and a full-thickness skin defect model of mice was made. The skin defects were treated with normal saline as a control and also the four kinds of platelet concentrates mentioned above, respectively. Wound size was measured and calculated on days 3, 5, 7, and 10, with histological analysis performed.

RESULTS

All four platelet concentrates accelerated wound healing in mice. Interleukin-1β (IL-1β) and tumor necrosis factor (TNF-α) in concentrated growth factors in a liquid phase, a gel phase, and artificial platelet-rich plasma groups were significantly lower than those in the control group; and vascular endothelial growth factor (VEGF) and CD34 were significantly higher than those in the control group and auto-platelet-rich plasma group.

CONCLUSIONS

All four platelet concentrates appear to promote wound healing. Compared with auto-platelet-rich plasma, concentrated growth factors in a liquid phase and in a gel phase, and artificial platelet-rich plasma seem to have more substantial effects in promoting angiogenesis, epithelialization, and reducing inflammation, thus promoting a stronger effect on wound healing.

Treatment of sinus membrane perforations during sinus lift surgeries using leukocyte and platelet-rich fibrin: A report of three cases

BACKGROUND AND AIM

Schneiderian membrane (SM) perforation is the most frequent intraoperative complication during sinus lifts, which can lead to implant failure or delayed implant treatment. This article aims to show the results of using leukocyte and platelet-rich fibrin (L-PRF) in the treatment of perforations occurring during sinus lifts with a lateral window approach.

RESULTS

Three patients (n = 5 implants) with a mean ± SD age of 57.67 ± 12.12 years were included, in whom perforations of the SM of 3-5 mm and >5 mm occurred. The mean ± SD preoperative bone height was 4.42 ± 2.96 and, at 6 months it was 9.58 ± 2.41 (P < 0.05). All implants had a 100% survival rate at 6-24 months. At the split-mouth, the mean ± SD baseline height was 5.05 ± 2.99 mm in repaired SM versus 2.92 ± 1.01 in those without any complications (P > 0.05). At 6 months, mean ± SD gains were 10.09 ± 2.44 mm versus 7.73 ± 0.90 mm, respectively, (P > 0.05).

CONCLUSION

L-PRF simplifies SM repair, reducing the need for high surgical experience and/or skills. Although there are no significant differences between repaired and intact SM, at the radiological level, greater bone compactness and maturation were observed in the latter, which may be associated with the presence of air bubbles caused by anaerobic bacterial activity in repaired SM.

RELEVANCE FOR PATIENTS

The use of L-PRF greatly simplifies the resolution of SM perforations during sinus lift surgeries, reducing treatment times, and providing predictable results. Being of autologous origin, it accelerates and enhances healing, eliminating the possibility of autoimmune rejection reactions.

Intentional Replantation as a Starting Approach for a Multidisciplinary Treatment of a Mandibular Second Molar: A Case Report

Intentional replantation (IR) may offer a solution for persistent periapical lesions associated with endodontically treated teeth. A 35-year-old male patient presented with pain associated with the left mandibular second molar and hypoesthesia. Upon clinical examination, increased probing pocket depth in the mid-buccal surface was detected. Cone beam computed tomography revealed a previous non-surgical root canal treatment, with root canal filling material extrusion adjacent to the inferior alveolar nerve, a fractured instrument in the mesial root, and a large periapical radiolucency involving both teeth 37 and 36. A diagnosis of symptomatic post-treatment apical periodontitis was established. After discussing treatment options with the patient, an IR of tooth 37 was performed. Extra-oral procedures were completed in 17 min. At 9 months, hypoesthesia resolution was reported, and apical healing was radiographically observed. After 2.5 years, the replanted tooth showed extensive root resorption. An extraction with alveolar ridge preservation, using leukocyte-platelet rich fibrin (L-PRF), was performed. Six months after tooth extraction and regeneration, implant placement surgery was carried out. IR presents a valid treatment modality for the management of post-treatment apical periodontitis. When orthograde retreatment or apical microsurgery prove to be unfeasible, IR is a unique procedure with the potential to promote tooth preservation in properly selected cases. Although unsuccessful after 2.5 years, the IR of tooth 37 allowed for bone regeneration, the maintenance of tooth 36 vitality, and hypoesthesia resolution.

Increased local concentrations of growth factors from leucocyte- and platelet-rich fibrin do not translate into improved alveolar ridge preservation: an intraindividual mechanistic randomized controlled trial

AIMS

Leucocyte- and platelet-rich fibrin (L-PRF) has been tested for enhancing alveolar ridge preservation (ARP), but little is known about the local release profile of growth factors (GF) and the clinical equipoise related to its efficacy remains. This study compared the patterns of GF release, early soft tissue healing and alveolar ridge resorption following unassisted healing and L-PRF application in non-molar extraction sockets.

MATERIALS AND METHODS

Atraumatic tooth extraction of two hopeless teeth per patient was followed by unassisted healing or L-PRF placement to fill the socket in 18 systemically healthy, nonsmoking subjects. This intraindividual trial was powered to assess changes in horizontal alveolar ridge dimensions 1 mm below the crest of alveolar bone. GF concentrations in wound fluid were assessed with a multiplex assay at 6, 24, 72 and 168 hours. Early healing was evaluated with the wound-healing index and changes in soft tissue volumes on serial digital scans. Hard tissue changes were measured on superimposed CBCT images after 5 months of healing.

RESULTS

L-PRF resulted in higher GF concentrations in WF as compared to the control, but no differences in release patterns or time of peak were observed. No intergroup differences in early healing parameters were observed. Alveolar bone resorption was observed in both groups. No significant intergroup differences were observed in hard tissue healing 1, 3 or 5 mm apical to the original bone crest, or in ability to digitally plan a prosthetically guided implant with or without bone augmentation.

CONCLUSIONS

L-PRF increased the GF concentrations in wound fluid of extraction sockets without shifting the pattern observed in unassisted healing, while the increased delivery did not translate into clinical benefits in early wound healing or ARP. The current findings question the assumption that increased local concentrations of GF by L-PRF translate into improved clinical outcomes. Additional definitive studies are needed to establish the benefits of L-PRF in ARP. (clinicaltrials.gov NCT03985033).

A three-in-one alveolar process reconstruction protocol for maxillary molar sites with severe residual bone height deficiency: A proof-of-concept pilot study

BACKGROUND

Implant placement in maxillary molar sites with severe height deficiency often requires multiple surgeries, which was time-consuming, invasive, and subject to serious postoperative complications.

PURPOSE

To introduce and assess a three-in-one technique (extraction, alveolar ridge preservation [ARP], and sinus elevation) for augmenting deficiency maxillary molar alveolar ridges.

MATERIAL AND METHODS

Fourteen patients with severe posterior maxillary ridge height deficiency underwent extraction, sinus elevation via an intrasocket window and ARP using sticky bone and then covered with acellular dermal matrix (ADM). Primary closure was intentionally not obtained. Cone-beam computed tomography and periapical radiography were used to measure dimensional ridge changes over time. Bone biopsies were taken at implant placement 7-21 months after surgery, which proceeded without additional grafting. Peri-implant soft tissue was assessed after 8-12 months of functional loading.

RESULTS

Maxillary molar sites (13 first molars, 1 second molar) with a mean sinus floor height of 1.73 ± 0.86 mm and mean buccal plate thickness of 1.62 ± 1.15 mm were elevated and grafted. Immediately after surgery, the mean sinus floor height was 14.03 ± 1.97 mm and the alveolar thickness at virtual implant platform level was 12.99 ± 1.88 mm. After 5-9 months healing, those measurements decreased by 2.45 ± 1.73 mm (p = 0.000) and 3.88 ± 3.95 mm (p = 0.006), respectively. Healed ridges were composed of 18.74% ± 4.34% mean vital bone and 19.08% ± 9.10% mean residual graft. After 8-12 months of functional loading, the peri-implant tissue appeared healthy, and there was a mean marginal bone loss of 0.12 ± 0.11 mm.

CONCLUSIONS

For maxillary first molar sites with severe sinus floor height deficiency, this minimally invasive three-in-one treatment allows for uncomplicated implant placement and short-term functional stability.

Mechanical properties and cellular content of leukocyte- and platelet-rich fibrin membranes of patients on antithrombotic drugs

INTRODUCTION

The aim of this study was to examine the potential influence of antithrombotics on leukocyte- and platelet-rich fibrin (L-PRF) membranes.

METHODS

Tensile tests and cell counts were performed with L-PRF membranes originating from patients on anticoagulants and antiplatelets versus patients not taking antithrombotics.

RESULTS

For the tensile tests, 13 control patients, 12 on anticoagulants, and 10 on antiplatelets donated blood. Compared to controls, membranes from anticoagulated donors were weaker (strength 0.57 ± 0.24 MPa vs. 0.80 ± 0.27 MPa, p = .03) and could not be stretched as far (1.8 ± 0.3 vs. 2.1 ± 0.3 times the initial length, p = .01). For the cell counting, 23 control patients, 16 on anticoagulants, and 16 on antiplatelets donated blood. The percentage of platelets was ±50% in the three groups. The percentage of leukocytes was lower in the anticoagulant group compared with controls (69 ± 10% vs. 78 ± 8%, p = .04). However, because of the unknown error of method, it is questionable whether the statistical significance is meaningful. There was no difference between membranes from the control group and the group on antiplatelets.

CONCLUSION

Our results indicate that L-PRF membranes originating from patients on anticoagulants are weaker, stretch less far, and contain less leukocytes than L-PRF membranes of patients not taking these drugs.

Immediate implant placement with platelet rich fibrin as space filling material versus deproteinized bovine bone in maxillary premolars: A randomized clinical trial

BACKGROUND

Several biomaterials have been suggested to augment the jumping gap during immediate implant placement.

PURPOSE

The aim of this study was to compare the effect of xenograft or platelet derived growth factor (PRF) to graft the jumping gap in immediate implant placement in the maxillary premolar region.

MATERIALS AND METHODS

Twenty patients underwent atraumatic extraction followed by immediate placement. The patients were equally divided into two groups. The first group received xenograft as a jumping gap filling material. The second group received PRF to graft the jumping gap. All patients received preoperative, immediate postoperative, and 6 months postoperative cone beam CT scan (CBCT). Implant stability quotient ISQ values were taken for the installed implants immediate postoperative and at 6 months.

RESULTS

Implants receiving PRF as a jumping gap graft material demonstrated a significantly greater amount of crestal bone loss 1.85 ± 0.89 mm as compared to xenograft group 0.77 ± 0.32 mm (t = 3.52, p = 0.005). PRF group showed significantly greater reduction in buccopalatal direction 1.63 mm as compared to xenograft group 0.59 mm (t = 4014, p <0.001). ISQ values were similar immediately postoperative (t = 0.070, p = 0.945) while the ISQ values were significantly lower in PRF group as compared to xenograft graft at the six-month interval (t = 0.248, p = 0.023).

CONCLUSION

The use of xenograft material as a jumping gap filling material resulted in superior results compared to PRF with regards to crestal bone loss, buccolingual socket reduction, and ISQ values.

Sinus Lift Associated with Leucocyte-Platelet-Rich Fibrin (Second Generation) for Bone Gain: A Systematic Review

The purpose of this systematic review was to analyze sinus lifting procedures and to compare the efficiency of this treatment associated with the second generation of platelet-rich fibrin related to its effects on bone gain and to clarify the regenerative efficacy in sinus lift procedure, whether alone or as a coadjutant to other bone graft materials. The PICOT question was, “In clinical studies with patients needing a maxillary sinus lift (P), does the use of PRF either alone (I) or in conjunction with other biomaterials (C) improve the clinical outcome associated with bone gain and density (O), with at least three months of follow-up (T)?” An electronic search was conducted in the MEDLINE (PubMed), Science Direct, and Scopus databases through a search strategy. A total of 443 articles were obtained from the electronic database search. Sixteen articles met all criteria and were included in this review. Within the limitation of this study and interpreting the results carefully, it was suggested that a higher risk for implant failure after a sinus elevation might be seen in patients with residual bone ≤4 mm, and PRF application was effective, suggesting reducing the time needed for new bone formation.

Treatment of oroantral communication with Platelet-Rich Fibrin: A systematic review

BACKGROUND

Oroantral communication (OAC) is the opening between the maxillary sinus and the oral cavity, which constitutes a gate for the mucosal infection in the maxillary sinus. On the other hand, an OAF develops when the OAC does not close spontaneously, remains manifest and is epithelialized. Several methods have been proposed to solve these situations, however, they are associated with increased postoperative morbidity and/or higher associated costs and require some experience of the surgeon to perform them. To overcome these disadvantages, the use of Platelet-Rich Fibrin (PRF) is proposed. The present study aims to perform a systematic review of the literature, collecting cases in which PRF was used in the treatment of OACs/OAFs.

MATERIALS AND METHODS

An electronic search of the MEDLINE database (via PubMed) and Web of Science was performed using the following MeSH terms (Medical Subjects Headings): (oroantral communication OR oroantral fistula OR buccosinusal communication) AND (platelet-rich fibrin OR prf OR fibrin mesh). The criteria used were those described by the PRISMA® Statement. The search was not time-restricted and was updated to April 2021.

RESULTS

After searching, 11 articles were included that met the established criteria. In these, PRF was used alone or in combination with bi- or trilaminar techniques achieving complete resolution in 100% of cases (n = 116).

CONCLUSIONS

With the limitations of this study, it can be established that PRF can be used alone for the treatment of OACs/OAFs up to 5 mm and, in larger defects, it is advisable to combine it with bi- or trilaminar techniques. PRF is an effective therapeutic option, with minimal associated postoperative morbidity compared to other techniques and allows the position of the mucogingival junction to be preserved. Its combination with bone grafting improves the starting point before the replacement of the missing tooth with a dental implant.

The Adjunctive Use of Leucocyte- and Platelet-Rich Fibrin in Periodontal Endosseous and Furcation Defects: A Systematic Review and Meta-Analysis

The aim of this systematic review of randomized controlled trials was to evaluate the adjunctive use of leucocyte- and platelet-rich fibrin (L-PRF) in periodontal endosseous and furcation defects, as compared without L-PRF. The endosseous defect group was subclassified into: L-PRF/open flap debridement (L-PRF/OFD) versus OFD, L-PRF/osseous graft (L-PRF/OG) versus OG, L-PRF/Emdogain (L-PRF/EMD) versus EMD, and L-PRF/guided tissue regeneration (L-PRF/GTR) versus GTR. The furcation defect group was subclassified into L-PRF/OFD versus OFD, and L-PRF/OG versus OG. Mean difference, 95% confidence intervals and forest plots were calculated for probing pocket depth (PPD), clinical attachment level (CAL) and radiographic defect depth (DD). Nineteen studies concerning systemically healthy non-smokers were included. The results of this systematic review and meta-analysis showed in two- and/or three-wall endosseous defects that the adjunctive use of L-PRF to OFD or OG was significantly beneficial for PPD reduction, CAL gain and DD reduction, as compared without L-PRF. Furthermore, the data showed that for two- and/or three-wall endosseous defects, the adjunctive use of L-PRF to GTR was significantly beneficial for CAL and DD improvement, whereas adding L-PRF to EMD had no significant effect, and that for class II furcation defects, the addition of L-PRF to OFD was significantly beneficial for PPD, CAL and DD improvement, whereas the addition of L-PRF to OG was significantly clinically beneficial. In conclusion, this systematic review and meta-analysis found that there was significant clinical and radiographic additive effectiveness of L-PRF to OFD and to OG in two- and/or three-wall periodontal endosseous defects of systemically healthy non-smokers, as compared without L-PRF.

Preparation, characterization and biological properties of a novel bone block composed of platelet rich fibrin and a deproteinized bovine bone mineral

Alveolar bone defects caused by tooth loss often lead to challenges in implant dentistry, with a need for development of optimal bone biomaterials to predictably rebuild these tissues. To address this problem, we fabricated a novel bone block using platelet-rich fibrin (PRF) and Deproteinized Bovine Bone Mineral (DBBM), and characterized their mechanical and biological properties. The bone block was prepared by mixing DBBM, Liquid-PRF, and Solid-PRF fragments in various combinations as follows: (1) BLOCK-1 made with Solid-PRF fragments + DBBM, (2) BLOCK-2 made with Liquid-PRF + DBBM, (3) BLOCK-3 made with Solid-PRF fragments + Liquid-PRF + DBBM. The time for solidification and the degradation properties were subsequently recorded. Scanning electron microscopy (SEM) and tensile tests were carried out to investigate the microstructure and mechanical properties of each block. The bioactivity of the three groups towards osteoblast differentiation was also evaluated by culturing cells with the conditioned medium from each of the three groups including cell proliferation assay, cell migration assay, alkaline phosphatase (ALP) staining, and alizarin red staining (ARS), as well as by real-time PCR for genes encoding runt-related transcription factor 2 (RUNX2), ALP, collagen type I alpha1(COL1A1) and osteocalcin (OCN). BLOCK-3 made with Solid-PRF fragments + Liquid-PRF + DBBM had by far the fastest solidification period (over a 10-fold increase) as well as the most resistance to degradation. SEM and tensile tests also revealed that the mechanical properties of BLOCK-3 were superior in strength when compared to all other groups and further induced the highest osteoblast migration and osteogenic differentiation confirmed by ALP, ARS and real-time PCR. PRF bone blocks made through the combination of Solid-PRF fragments + Liquid-PRF + DBBM had the greatest mechanical and biological properties when compared to either used alone. Future clinical studies are warranted to further support the clinical application of PRF bone blocks in bone regeneration procedures.

Impact of local and systemic antimicrobials on leukocyte- and platelet rich fibrin: an in vitro study

The aim of this study was to evaluate the effect of local and systemic administration of antimicrobials to leukocyte- and platelet-rich fibrin (L-PRF). For part A, 16 tubes of venous blood were collected from each of eight systemically healthy subjects. Prior to blood centrifugation, 12 of the 16 tubes were injected with 0.125 ml, 0.25 ml or 0.50 ml metronidazole solution. One set of L-PRF membranes was used to assess the release of vascular endothelial growth factor AB, platelet-derived growth factor, transforming growth factor beta 1, and bone morphogenetic protein 2 at indicated time points. The metronidazole release over time by L-PRF membranes was also evaluated. The remaining L-PRF membranes were placed on the surface of agar plates inoculated with three different periodontal pathogens to determine their antibacterial activity. For part B, another six subjects were enrolled with three subjects taking 2 g amoxicillin and three subjects 500 mg metronidazole as prophylaxis prior to a periodontal treatment. Before and 2 h after consuming one of the prescribed antimicrobials, three tubes of blood were collected for preparing L-PRF membranes. These membranes were used to measure the antibacterial activity against periodontal pathogens. No statistically significant difference could be found in the release of growth factors between L-PRF membranes with and without incorporation of metronidazole solution. The release of metronidazole could be detected up to day 3, however with the highest concentration during the first 4 h. This concentration was dose dependent. The antibacterial capacity of L-PRF membranes increased significantly for both the systemic intake, and after the addition of metronidazole solution to the blood tubes before centrifugation, the latter again dose dependent. The antibacterial capacity of L-PRF against the periodontal pathogens tested can significantly be enhanced by the addition of antimicrobials, without disadvantage for the release of growth factors.

From Blood to Bone-The Osteogenic Activity of L-PRF Membranes on the Ex Vivo Embryonic Chick Femur Development Model

(1) Background: To evaluate the effects of the direct and indirect contact of leukocyte and platelet-rich fibrin (L-PRF) on bone development, in an ex vivo embryonic chick femur model. (2) Methods: Both sections of L-PRF membranes (red and yellow portions) were evaluated with scanning electron microscopy and histochemical staining. The in vivo angiogenic activity was evaluated using a chorioallantoic membrane model. The osteogenic activity was assessed with an organotypic culture of embryonic chick femora through direct and indirect contact, and assessment was conducted by microtomographic and histological analysis. Descriptive statistics, One-Way ANOVA and Tukey’s multiple comparisons tests were performed for datasets that presented a normal distribution, and Kruskal-Wallis tests were performed for non-parametric datasets. A significance level of 0.05 was considered. (3) Results: The L-PRF induced angiogenesis reflected by a higher number and a larger and more complex gauge in the vessels that invaded the membrane. The physical presence of the membrane over the bone (direct contact) unleashes the full potential of the L-PRF effects on bone growth enhancement. The greatest increase in mineral content was observed in the diaphysis region. (4) Conclusion: The L-PRF direct contact group presented higher values on mineral content for bone volume, bone surface and bone mineral density than the indirect contact and control groups.

Hard Tissue Preservation and Recovery in Minimally Invasive Alveolar Surgery Using Three-Dimensional Printing Guide Plate

BACKGROUND

For completely impacted teeth, it is of great significance to locate teeth accurately, preserve hard tissue and recovering the height of alveolar ridge. This can be effectively solved by the digital three-dimensional printing guide technology.

METHODS

Ten patients with completely impacted tooth were selected in this experiment. After cone-beam computed tomography scan, the dicom formal computed tomography data was analyzed for three-dimensional reconstruction by mimics 17.0 software. Then determining the surgical plan and making surgical guide plate. Three-dimensional printing guide plate assisted piezosurgery was used to remove bone and extract impacted teeth. After that, the removed bone cap was back to the original position. Cone-beam computed tomography was used for each operated patients after 1 week and 6 months.

RESULT

The surgical guide plates can locate teeth accurately and the surgery time was reduced for all patients. A week later, all patients healed well and removed the stitches on time. Cone-beam computed tomography showed that the retention of bone caps was good and there was no displacement. All patients showed a normal parameter of pain. Six months later, cone-beam computed tomography showed good bone formation in the extraction area, which filled with new bones completely. The recovery of bone outline and height of alveolar crest at the surgical site were basically consistent with those before the operation.

CONCLUSIONS

Three-dimensional printing guide plates combining with fenestration and bone-cap restoration can locate impacted teeth accurately, reduce the extraction volume of bone, shorten surgery time, and alleviate complications. This was conducive to preserve and restore hard tissue and had great prospective.

Structure, Barrier Function, and Bioactivity of Platelet-Rich Fibrin Following Thermal Processing

Platelet-rich fibrin (PRF) has been utilized as a substitute for resorbable membranes during guided bone regeneration therapy as it is a more bioactive biomaterial with living cells and growth factors than resorbable membranes. Nevertheless, PRF poses obvious disadvantages in its mechanical strength since its rapid degradability has been shown to typically resorb within a 2-week time period. In the present study, the barrier function and biological and mechanical properties of PRF were investigated both as standard therapy and after thermal processing. Two heating processes were applied: both single-side heating and double-side heating at 90°C for 10 s using a metal plate heater. The appearance and weight of PRF membranes were documented after heating, along with their morphological and mechanical properties evaluated by scanning electron microscope and tensile strength tests. The viability of cells found within PRF membranes was also evaluated using live/dead cell viability and CCK-8 (cell counting kit-8) assays. To comprehensively evaluate the barrier function of PRF membranes, Hoechst staining of human gingival fibroblasts, which can be distinguished from cells within the PRF membrane by emitting blue light at an excitation wavelength of 488 nm, was seeded onto the surface of PRF membranes. Furthermore, osteoblasts were cultured with extracts from different PRF groups to evaluate the biocompatibility of PRF membranes. The degradation rate of PRF membranes was examined by digestion assay. Compared with the nonheated PRF control, the size and weight of PRF membranes led to a significant decrease with a denser PRF microstructure following heating. In summary, the double-sided heating of PRF membranes not only demonstrated an improvement in mechanical and degradation properties but also led to a decrease in cell viability and proliferation.

Assessment of the Effect of A-PRF Application during the Surgical Extraction of Third Molars on Healing and the Concentration of C-Reactive Protein

Extraction procedures for mandibular third molars are performed all over the world every day. Local inflammation resulting from surgery, and the pain that patients experience, often make it impossible to take up daily life activities, such as work or sports. Growth and anti-inflammatory factors, located in the fibrin network, have a positive effect on tissue-healing processes and should also reduce local inflammation. Advanced platelet-rich fibrin (A-PRF) applied locally influences such processes as: angiogenesis, osteogenesis and collagenogenesis. It also affects mesenchymal cell lines and anti- and pro-inflammatory mediators. Due to the autologous origin of the material, their use in guide bone regeneration (GBR) is more and more widespread in dentistry. The results of previous studies indicate that the use of A-PRF in the treatment area significantly reduces postoperative pain, while the formation of edema is not affected. C-reactive protein (CRP), which is an acute phase protein, appears in the blood as a consequence of inflammation. Due to the dynamics of changes in concentration of CRP, it is a protein that is sufficiently sensitive and is used in studies to monitor the tissue healing process. The effect of A-PRF application on CRP concentrations, before and after surgery, has not been investigated yet. The study was conducted on 60 generally healthy patients. A faster decrease of CRP levels was shown in patients who used A-PRF after the procedure. Additionally, it accelerated healing and reduced the occurrence of a dry socket close to 0.

Regenerative Endodontic Procedure of Immature Permanent Teeth with Leukocyte and Platelet-rich Fibrin: A Multicenter Controlled Clinical Trial

INTRODUCTION

The aim of this nonrandomized, multicenter controlled clinical trial was to evaluate the impact of leukocyte-platelet-rich fibrin (LPRF) on regenerative endodontic procedures (REPs) of immature permanent teeth in terms of periapical bone healing (PBH) and further root development (RD).

METHODS

Healthy patients between 6-25 years with an inflamed or necrotic immature permanent tooth were included and divided between the test (= REP + LPRF) and control (= REP-LPRF) group depending on their compliance and the clinical setting (university hospital or private practice). After receiving REP ± LPRF, the patients were recalled after 3, 6, 12, 24, and 36 months. At each recall session, the teeth were clinically and radiographically (by means of a periapical radiograph [PR]) evaluated. A cone-beam computed tomographic (CBCT) imaging was taken preoperatively and 2 and 3 years postoperatively. PBH and RD were quantitatively and qualitatively assessed.

RESULTS

Twenty-nine teeth with a necrotic pulp were included, from which 23 (9 test and 14 control) were analyzed. Three teeth in the test group had a flare-up reaction in the first year after REP. Except for 2 no shows, all the analyzed teeth survived up to 3 years after REP, and, in case of failure, apexification preserved them. Complete PBH was obtained in 91.3% and 87% of the cases based on PR qualitative and quantitative evaluation, respectively, with no significant difference between the groups with respect to the baseline. The PR quantitative change in RD at the last recall session with respect to the baseline was not significant (all P values > .05) in both groups. The qualitative assessment of the type of REP root healing was nonuniform. In the test group, 55.6% of the teeth presented no RD and no apical closure. Only 50% of the 14 teeth assessed with CBCT imaging presented complete PBH. Regarding volumetric measurements on RD 3 years after REP for the change with respect to the baseline in root hard tissue volume, mean root hard tissue thickness, and apical area, the control group performed significantly in favor of RD than the test group (P = .03, .003, and 0.05 respectively). For the volumetric change 3 years after REP with respect to the baseline in root length and maximum root hard tissue thickness, no significant difference (P = .72 and .4, respectively) was found between the groups. The correlation between the PR and CBCT variables assessing RD was weak (root lengthening) to very weak (root thickening).

CONCLUSIONS

REP-LPRF seems to be a viable treatment option to obtain PBH and aid further RD of necrotic immature permanent teeth. Caution is needed when evaluating REP with PR.

Application of Platelet-Rich Fibrin Derivatives for Mandibular Third Molar Extraction Related Post-Operative Sequelae: A Systematic Review and Network Meta-Analysis

PURPOSE

Leukocyte- and platelet-rich fibrin (L-PRF) and advanced-platelet-rich fibrin (A-PRF) that are derivatives of PRF (platelet-rich fibrin) accelerate wound healing and reduce postoperative sequelae after tooth extraction. This network meta-analysis aimed to investigate the effectiveness of L-PRF and A-PRF in mandibular third molar extraction and provide suggestions for alleviating postoperative symptoms and signs.

METHODS

A comprehensive search of the literature was conducted in PubMed, Embase, Web of Science, and SinoMed databases up to Oct 9, 2020. Three types of randomized controlled trials were included to investigate the effects of PRF derivatives after extracting mandibular third molars: A-PRF and L-PRF groups; A-PRF and control groups; L-PRF and control groups. Their relative effectiveness and ranking were assessed using network meta-analysis and the surface under the cumulative ranking curve (SUCRA) with STATA 16.0 and Revman 5.3, respectively.

RESULTS

Ten randomized controlled trials were included, with 307 mandibular third molar extraction patients involved. The results showed that A-PRF had the best effect among the 3 groups in improving postoperative pain on the third (SUCRA = 98.2%) and seventh (SUCRA = 88.4%) days; L-PRF promoted soft tissue healing (MD = -0.90, 95% CI [-1.40, -0.40], P = .0004) on the seventh day compared with the control. However, other comparisons showed no significant differences (P > .05).

CONCLUSION

The limited results confirmed that PRF derivatives only reduced some postoperative symptoms and did not prevent them all. Application of A-PRF after third molar extraction reduced postoperative pain, and L-PRF improved the degree of soft tissue healing.

A retrospective preliminary histomorphometric and clinical investigation on sinus augmentation using enzyme-deantigenic, collagen-preserving equine bone granules and plasma rich in growth factors

Background

Enzyme-deantigenic equine bone (EDEB) is a substitute of autogenous bone. Mixing it with plasma rich in growth factors (PRGF) seems a viable option to achieve enhanced bone formation in alveolar bone augmentation surgeries. This retrospective study aims to first report the histomorphometric and clinical outcomes achieved when using the EDEB/PRGF mixture for performing sinus augmentation procedures followed by delayed implant placement.

Materials and methods

Records of 11 patients who underwent 14 sinus augmentation surgeries using EDEB/PRGF followed by delayed implant placement were retrospectively collected and analyzed to assess histomorphometric data concerning newly formed bone (NFB) and residual biomaterial (RB) recorded at implant placement, marginal bone loss (MBL) values of implants placed in the augmented sinuses, and implant and prosthetic success and survival rates.

Results

At 5.6 ± 1.1 months after grafting, NFB and RB were 34.0 ± 9.1% and 11.3 ± 2.2% respectively, and no histologic signs of inflammation or immune reaction were observed in any of the 34 bone biopsies being collected. Further, 86.5 ± 4.3 months after implant placement, MBL was 0.40 ± 0.07 mm. No implant or prosthesis failed, and the implant success and survival rates were 100%

Conclusions

Within the limitations of the present study, grafting EDEB/PRGF for lateral sinus augmentation and delayed implant placement seems to be safe. Compared to published data concerning EDEB alone, results of the present study do not suggest that the EDEB/PRGF combination may provide a histomorphometric or medium-/long-term clinical advantage.

Effects of relative centrifugation force on L-PRF: An in vivo submandibular boney defect regeneration study

Properties and composition of leukocyte- and platelet-rich fibrin (L-PRF) clots may be largely affected by centrifugation protocols (function of relative centrifugal force [RCF]), which may impact biological potential repair in bone regeneration. The present in vivo study sought to assess the effect of the RCF on the composition of L-PRF clots, as well as to compare the repair potential of L-PRF clots obtained with different RCF protocols in submandibular boney defects using PLGA scaffolds for bone regeneration. Complete blood count and volumetric evaluations were performed on L-PRF clots obtained through centrifugation for 12 min at 200, 400, and 600 RCF-clot centrifugation speeds. These evaluations were completed from blood collected immediately prior to any surgical procedures. The in vivo portion comprised of three submandibular unilateral, full thickness, osteotomies (~0.40cm³ ) which were created in the submandibular region of six sheep, using rotary instrumentation under continuous irrigation. Subsequently, poly(lactic-co-glycolic acid) (PLGA) scaffolds were enveloped in a L-PRF membrane from one of the three spinning speeds (n = 6/RCF) and inserted into the defect (sites were interpolated to avoid site bias). Six-weeks after surgery, the mandibles were harvested en bloc and prepared for volumetric and histomorphometric evaluations. Membranes harvested from 600 RCF produced significantly larger L-PRF clots (6.97g ± 0.95) in comparison to the lower 200 RCF (5.7g ± 0.95), with no significant differences between 600 and 400, and from 400 and 200 RCF. The three tested RCFs did not alter the platelet count of the L-PRF clot. For the in vivo component, quantitative bone regeneration analyses demonstrated significantly higher values obtained with L-PRF membranes extracted post 600 RCF (27.01 ± 8%) versus 200 RCF (17.54 ± 8%), with no significant differences regarding 400 RCF (~23 ± 8%). At the qualitative histological analyses, L-PRF membranes obtained at 600 and 400 RCFs yielded improved healing throughout the defect, where the L-PRF sourced from the lowest speed, 200 RCF, presented healing primarily at the margins along with the presence of connective tissue at the central aspect of the surgical defect. Higher 600 RCF yielded larger L-PRF clots/membranes, resulting in enhanced bone repair potential in association with PLGA scaffolds for the treatment of critical size bone defects.

Guided bone regeneration simultaneous with implant placement using bovine-derived xenograft with and without liquid platelet-rich fibrin: a randomized controlled clinical trial

OBJECTIVE

To assess augmentation success after guided bone regeneration (GBR) carried out simultaneously with implant placement using bovine-derived xenograft alone and in combination with liquid platelet-rich fibrin (liquid-PRF).

METHODS

This randomized controlled clinical trial was conducted on patients with horizontal bone deficiency in the posterior regions of the mandible. After implant placement, GBR procedures were randomly performed using liquid-PRF-enriched bovine-derived xenograft (for the test group) and with bovine-derived xenograft alone (for the control group). To assess the change in augmentation thickness, the primary outcome of the study, cone beam computed tomography was carried out at the implant sites on completion and 6 months after surgery. The secondary outcomes were marginal bone level and implant survival rate at prosthetic delivery and at 6 months, 1 year, and 2 years follow-up after loading. The significance level was set at p<0.05 for all analysis.

RESULTS

Twenty patients with 50 implants were analyzed for the test group and 20 patients with 48 implants for the control group. At 6 months postoperatively, the mean values of augmentation thickness were 1.63 ± 0.21 mm, 2.59 ± 0.34 mm, and 3.11 ± 0.36 mm for the test group and 1.34 ± 0.14 mm, 2.49 ± 0.24 mm, and 2.97 ± 0.24 mm for the control group at 2 mm, 4 mm, and 6 mm below to the implant shoulder (p < 0.001, p = 0.007, and p = 0.036, respectively). The mean marginal bone loss was found to be less than 1 mm for both study groups during the 2 years of follow-up after prosthetic loading. Implant survival rate was 100% for both study groups.

CONCLUSION

Bovine-derived xenograft alone and in combination with liquid-PRF are both successful in achieving bone augmentation around the implants and produce a small change in marginal bone level and a high implant survival rate after loading.

CLINICAL RELEVANCE

There is a lack of evidence in the literature regarding the augmentation success of liquid-PRF used in combination with bone graft substitutes. This study indicates that liquid-PRF could be used as a supportive material with bovine-derived xenograft in GBR procedures carried out simultaneously with implant placement.

Effect of different platelet-rich fibrin matrices for ridge preservation in multiple tooth extractions: A split-mouth randomized controlled clinical trial

AIM

To evaluate dimensional changes in the alveolar ridge and bone structure after tooth extraction when L-PRF or A-PRF+ was used in comparison to unassisted socket healing.

MATERIALS AND METHODS

Twenty patients in need of at least three tooth extractions in the aesthetic zone were included. L-PRF, A-PRF+ or control was randomly assigned, leaving one empty socket/edentulous site between conditions. CBCT scans were obtained immediately after tooth extraction and after 3 months of healing. Horizontal and vertical dimensional changes of the ridge and socket fill were calculated. Histological and micro-CT analysis of bone biopsies were used to evaluate post-surgical bone structural healing.

RESULTS

Mean horizontal and vertical changes at 1-mm below the crest (buccal and palatal side) were similar for the three sites (p > 0.05). For the socket fill, L-PRF (85.2%) and A-PRF+ (83.8%) showed superior values than the control (67.9%). The histological and radiological analysis reported more newly formed bone for the PRF groups, without any significant differences between both.

CONCLUSIONS

PRF matrices failed to reduce the dimensional changes after multiple tooth extractions in the premaxilla. After 3-month healing, both PRF matrices showed radiographically a significant superiority for the socket fill. Histologically, they seemed to accelerate new bone formation.

Impact of g force and timing on the characteristics of platelet-rich fibrin matrices

Recently, new centrifugation protocols for the preparation of platelet-rich fibrin (PRF) have been introduced in an attempt to further improve the beneficial impact of these 2nd generation platelet concentrate membranes. This in-vitro study aimed to compare the biological and physical characteristics of three types of PRF membranes using two different centrifuges with adapted relative centrifugal forces (RCF): leucocyte- and platelet-rich fibrin, advanced platelet-rich fibrin, and advanced platelet-rich fibrin⁺. Release of growth factors, macroscopic dimensions, cellular content and mechanical properties of the respective membranes, prepared from blood of the same individual were explored. Furthermore, the impact of timing (blood draw-centrifugation and centrifugation-membrane preparation) was assessed morphologically as well as by electron microscopy scanning. No statistically significant differences amongst the three PRF modifications could be observed, neither in their release of growth factors or the cellular content, nor in clot/membrane dimensions. The difference between both centrifuges were negligible when the same g-force was used. A lower g-force, however, reduced membrane tensile strength. Timing in the preparation process had a significant impact. Adaptation of RCF only had a minimal impact on the final characteristics of PRF membranes.