Incorporating antibiotics into platelet-rich fibrin: A novel antibiotics slow-release biological device

Development of a super-hydrophilic anaerobic tube for the optimization of platelet-rich fibrin

Horizontal platelet-rich fibrin (H-PRF) contains a variety of bioactive growth factors and cytokines that play a key role in the process of tissue healing and regeneration. The blood collection tubes used to produce Solid-PRF (plasmatrix (PM) tubes) have previously been shown to have a great impact on the morphology, strength and composition of the final H-PRF clot. Therefore, modification to PM tubes is an important step toward the future optimization of PRF. To this end, we innovatively modified the inner wall surface of the PM tubes with plasma and adjusted the gas environment inside the PM tubes to prepare super-hydrophilic anaerobic plasmatrix tubes (SHAP tubes). It was made anaerobic for the preparation of H-PRF with the aim of improving mechanical strength and bioactivity. The findings demonstrated that an anaerobic environment stimulated platelet activation within the PRF tubes. After compression, the prepared H-PRF membrane formed a fibrous cross-linked network with high fracture strength, ideal degradation characteristics, in addition to a significant increase in size. Thereafter, the H-PRF membranes prepared by the SHAP tubes significantly promoted collagen synthesis of gingival fibroblast and the mineralization of osteoblasts while maintaining excellent biocompatibility, and advantageous antibacterial properties. In conclusion, the newly modified PRF tubes had better platelet activation properties leading to better mechanical strength, a longer degradation period, and better regenerative properties in oral cell types including gingival fibroblast and alveolar osteoblasts. It also improves the success rate of H-PRF preparation in patients with coagulation dysfunction and expands the clinical application scenario.

How to explain the beneficial effects of leukocyte- and platelet-rich fibrin

The survival of an organism relies on its ability to repair the damage caused by trauma, toxic agents, and inflammation. This process involving cell proliferation and differentiation is driven by several growth factors and is critically dependent on the organization of the extracellular matrix. Since autologous platelet concentrates (APCs) are fibrin matrices in which cells, growth factors, and cytokines are trapped and delivered over time, they are able to influence that response at different levels. The present review thoroughly describes the molecular components present in one of these APCs, leukocyte- and platelet-rich fibrin (L-PRF), and summarizes the level of evidence regarding the influence of L-PRF on anti-inflammatory reactions, analgesia, hemostasis, antimicrobial capacity, and its biological mechanisms on bone/soft tissue regeneration.

Impact of aminopenicillin administration routes on antimicrobial effects of platelet-rich fibrin: An in-vitro investigation

INTRODUCTION

The aim of the study was to investigate the impact of different aminopenicillin administration routes on the antimicrobial effects of platelet-rich fibrin (PRF).

METHODS

We enrolled patients undergoing treatment with amoxicillin/clavulanic acid (AMC) orally or ampicillin/sulbactam (SAM) intravenously. AMC was applied in a single oral dose (875/125 mg), or in a double oral dose (1750/250 mg), and SAM in a dose of 2000/1000 mg. Blood was obtained one hour after the intake of AMC or 15 min after the infusion of SAM ended. Antimicrobial effects were investigated in agar diffusion tests with fresh PRF, PRF stored for 24, and PRF stored for 48 h. Agar diffusion tests were performed with Escherichia coli, Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus influenzae, and Porphyromonas gingivalis. Inhibition zones (IZs) around a 6 mm PRF disc were measured after 24 h.

RESULTS

IZs for fresh PRF and the single oral dose of AMC were 0.0, 4.7, 15.2, 2.3, and 0.9 mm (E. coli, S. aureus, S. pneumoniae, H. influenzae, and P. gingivalis, respectively). For the double oral dose, these values were 0.0, 11.4, 20.0, 8.1, and 7.4 mm. IZs for SAM were 11.9, 18.2, 24.7, 20.3, and 22.1 mm. Differences between parenteral and oral application as well as between different oral doses were significant (p<0.0001, one-way ANOVA).

DISCUSSION

The results of our study demonstrate that oral administration is a suitable route to load PRF with these drugs. This could expand the scope of PRF application to prevent infections at the surgical site, especially in an outpatient setting in which drugs are normally applied orally.

Comparative Evaluation of L-PRF and Ofloxacin Incorporated L-PRF as an Adjunctive to SRP-A Split-Mouth Randomized Clinical Trial

Aim and Objectives

To compare and evaluate the clinical efficacy of "ofloxacin incorporated L-PRF" and "L-PRF alone" when used as an adjuvant to non-surgical periodontal therapy.

Materials and Methods

A split-mouth study was conducted in 50 patients diagnosed as chronic periodontitis with pocket depth ≥6 with at least one site in each quadrant. All patients underwent scaling and root planning. Test site received with ofloxacin incorporated L-PRF and control site received L-PRF alone. Clinical parameters pocket depth (PD), plaque index (PI), and gingival bleeding index (GBI) were recorded at baseline and 1 month after scaling and root planning.

Results

In total, 100 sites were treated (50 test group and 50 control group) with no uneventful healing effects. Statistically significant decreases in PD (P = .0001 for both test and control groups), PI (P = .001), GBI (P = .001 for both groups), between pre-treatment and 1 month post-treatment were noted in both test and control groups. For intergroup comparisons, there was a statistically significant difference in all clinical indices (P > .005).

Conclusion

Use of L-PRF with ofloxacin as an adjuvant to non-surgical periodontal therapy showed better improvements in clinical parameters.

Antimicrobial effects of clindamycin-loaded platelet-rich fibrin (PRF)

OBJECTIVES

Recent research has demonstrated that platelet-rich fibrin (PRF) is an appropriate carrier for ampicillin/sulbactam. The aim of the study was to investigate whether PRF is also a suitable bio-carrier for clindamycin (CLI).

METHODS

PRF membranes were produced from 36 patients receiving intravenous therapy with CLI (e.g. due to the diagnosis of an osteonecrosis of the jaw or infections). Concentrations of CLI in PRF membranes were measured with liquid chromatography-tandem mass spectrometry, and the antimicrobial effects were investigated in vitro in agar diffusion tests with fresh PRF and PRF stored for 24 h. Storage was performed in an incubator at 36 °C to simulate the in-vivo situation.

RESULTS

The mean concentration of CLI in plasma was 1.0 ± 0.3 μg/100 mg plasma; in resulting PRF membranes 0.7 ± 0.4 μg/100 mg PRF. Agar diffusion tests were performed with Staphylococcus aureus, Streptococcus pneumoniae, Streptococcus mitis, Porphyromonas gingivalis, and Fusobacterium nucleatum. Mean inhibition zones, in mm, for fresh PRF were 17.3, 12.2, 18.8, 17.1, 25.8 and 18.1, 12.7, 19.2, 17.3, and 26.3 for stored PRF, respectively.

CONCLUSION

The results demonstrate that PRF is a suitable bio-carrier for CLI when administered systemically to patients. The concentration in PRF generated from patients after infusion of 600 mg CLI dose suffices to target clinically relevant bacteria.

CLINICAL RELEVANCE

Using PRF as a carrier for local antibiotic application can prevent infections in oral and maxillofacial surgery. Within the study limitations, the findings could expand the scope of PRF application by adding CLI as a new antibiotic to the spectrum of PRF therapy.

Antimicrobial effect of platelet-rich fibrin: A systematic review of in vitro evidence-based studies

This systematic review (SR) aimed to evaluate the antimicrobial potential of different types of platelet-rich fibrin (PRF) often used in regenerative treatments. An electronic search was performed in four databases and in Gray literature for articles published until January, 2023. The eligibility criteria comprised in vitro studies that evaluated the antimicrobial effect of different types of PRF. For the analysis of the risk of bias within studies, the modified OHAT (Office of Health Assessment and Translation) tool was used. For the evaluation of the results, a qualitative critical analysis was carried out in the synthesis of the results of the primary studies. Sixteen studies published between 2013 and 2021 were included in this SR. The antimicrobial effects of PRF variations (PRF, injectable PRF [I-PRF], PRF with silver nanoparticles [agNP-PRF], and horizontal PRF [H-PRF]), were analyzed against 16 types of bacteria from the oral, periodontal, and endodontic environments. All types of PRF showed significant antimicrobial action, with the antibacterial efficacy being more expressive than the fungal one. The I-PRF, H-PRF, and agNP-PRF subtypes improve antimicrobial activity. According to the OHAT analysis, no study was classified as having a high risk of bias. Evidence suggests that PRF variations have significant antimicrobial activity, with bacterial action being greater than fungal. Evolutions such as I-PRF, H-PRF, and agNP-PRF improve antimicrobial activity. Future studies analyzing the clinical effect of these platelets are fundamental. This SR was registered in INPLASY under number INPLASY202340016.

The impact of local and systemic penicillin on antimicrobial properties and growth factor release in platelet-rich fibrin: In vitro study

OBJECTIVE

This study evaluates the impact of local and systemic administration of penicillin on the antimicrobial properties and growth factors of platelet-rich fibrin (PRF) under in vitro conditions.

MATERIALS AND METHODS

The study involved 12 volunteers. Four tubes of venous blood were collected before systemic antibiotic administration. Two tubes were centrifuged at 2700 RPM for 12 min to obtain PRF, while 0.2 ml of penicillin was locally added into other two tubes. After systemic administration, blood samples were again collected and subjected to centrifugation. The release of growth factors (IGF-1, PDGF, FGF-2, and TGFβ-1) was determined using the Enzyme-Linked Immunosorbent Assay (ELISA), and an antibiotic sensitivity test was performed for S. aureus and E. coli bacteria.

RESULTS

Results showed that local antibiotic addition before PRF centrifugation had a significant antimicrobial effect without affecting growth factor releases. There was no statistically significant difference in antimicrobial properties between PRF prepared with systemic antibiotic administration and PRF prepared without antibiotics.

MATERIALS AND METHODS

The study suggests that incorporating localized antibiotics into PRF results in strong antimicrobial effects without compromise of growth factor release. However, the combination of PRF with systemic antibiotics did not significantly enhance its antimicrobial properties compared to PRF prepared without antibiotics.

CLINICAL RELEVANCE

Local addition of penicillin into PRF provides strong antimicrobial properties which may help reduce dependence on systemic antibiotic regimens, mitigating antibiotic resistance and minimizing associated side effects.

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.

Understanding Solid-Based Platelet-Rich Fibrin Matrices in Oral and Maxillofacial Surgery: An Integrative Review of the Critical Protocol Factors and Their Influence on the Final Product

Platelet-rich fibrin (PRF) is a second-generation platelet concentrate whose use in clinical practice has been widely disseminated. This has led to the development of several commercial protocols, creating great confusion as to the terminology and implications of each of them. This integrative review aims to identify the critical factors of each of the phases of the solid-based PRF matrix protocol and their possible influence on their macro- and microscopic characteristics. An electronic search of the MEDLINE database (via PubMed), Web of Science, Scopus, LILACS, and OpenGrey was carried out. The search was temporarily restricted from 2001 to 2022. After searching, 43 studies were included that met the established criteria. There were numerous factors to consider in the PRF protocol, such as the material of the blood collection tubes, the duration of phlebotomy, the parameters related to blood centrifugation, the time from centrifugation to dehydration of the fibrin clots and their dehydration into membranes, as well as the time to clinical use. These factors influenced the macro- and microscopic characteristics of the PRF and its physical properties, so knowledge of these factors allows for the production of optimised PRF by combining the protocols and materials.

Investigation of three common centrifugation protocols for platelet-rich fibrin (PRF) as a bio-carrier for ampicillin/sulbactam: a prospective trial

OBJECTIVES

Different platelet-rich fibrin (PRF) protocols exist and are known to differ in resulting mechanical and bioactive properties. Centrifugation parameters may also influence drug release, in particular antibiotics, when using PRF as a bio-carrier. We thus evaluated three common protocols regarding effects on the bio-carrier properties.

MATERIALS AND METHODS

In a prospective trial comprising 33 patients, we compared different protocols for PRF as a bio-carrier for ampicillin/sulbactam (SAM). Blood samples were taken shortly after a single dose of ampicillin/sulbactam (2 g/1 g) was administered to patients intravenously. PRF was obtained by centrifugation and three protocols were used: protocol A (1300 rpm, 8 min, RCF-max = 208 g), B (2300 rpm, 12 min, RCF-max = 652 g), and C (1500 rpm, 14 min, RCF-max = 276 g). The antibacterial activity of PRF was investigated against five oral species in vitro, based on agar diffusion methodology.

RESULTS

The study demonstrates that a single dose of SAM is sufficient to reach high concentrations in PRF in all protocols (150 µg/ml), which is comparable to the plasma SAM concentration. Antibacterial activity was inferred from the diameter of inhibition zones seen in agar diffusion tests using PRF discs. Protocol B resulted in the largest inhibition zones. One-way ANOVA revealed statistically improved results for protocol B for some bacteria.

CONCLUSIONS

The study provides valuable data on PRF antibiotic enrichment, notably SAM. A single dose of SAM is sufficient to reach clinically relevant concentrations in PRF.

CLINICAL RELEVANCE

These findings potentially extend the application of PRF, for example in patients with osteonecrosis of the jaw or in oral surgery (e.g., stick bone).

Comparison of Antimicrobial Activity against Porphyromonas gingivalis between Advanced Platelet-Rich Fibrin and Injectable Platelet-Rich Fibrin

Platelet-rich fibrin (PRF) obtained via low-speed centrifugation has antimicrobial properties. This study was conducted to evaluate the effectiveness of advanced platelet-rich fibrin plus (A-PRF+) and injectable platelet-rich fibrin (I-PRF), obtained from patients with different periodontal states, against Porphyromonas gingivalis. A-PRF+ and I-PRF samples were obtained from venous blood of 60 subjects divided equally into three groups: periodontitis, gingivitis, and healthy gingiva groups. The antibacterial experiments evaluated biofilm inhibition, mature biofilm impact, and time-kill kinetics. The percent reduction in biofilm-growing and mature biofilm bacteria ranged from 39% to 49% and 3% to 7%, respectively. In the time-kill kinetics assay, PRF from the periodontitis group was more effective as an antimicrobial than that from the gingivitis and healthy gingiva group ( $p<0.001$ ); I-PRF was more effective than A-PRF+ ( $p<0.05$ ) and both of them showed peak antibacterial activity after 12 h of exposure. Both A-PRF+ and I-PRF exhibited antibacterial properties against P. gingivalis, but I-PRF appeared to be more effective. The PRF obtained from the different groups appeared to have different degrees of antimicrobial efficacy.

Can platelet-rich fibrin act as a natural carrier for antibiotics delivery? A proof-of-concept study for oral surgical procedures

OBJECTIVES

Evaluate the role of platelet-rich fibrin (PRF) as a natural carrier for antibiotics delivery through the analysis of drug release and antimicrobial activity.

MATERIALS AND METHODS

PRF was prepared according to the L-PRF (leukocyte- and platelet-rich fibrin) protocol. One tube was used as control (without drug), while an increasing amount of gentamicin (0.25 mg, G1; 0.5 mg, G2; 0.75 mg, G3; 1 mg, G4), linezolid (0.5 mg, L1; 1 mg, L2; 1.5 mg, L3; 2 mg, L4), vancomycin (1.25 mg, V1; 2.5 mg, V2; 3.75 mg, V3; 5 mg, V4) was added to the other tubes. At different times the supernatant was collected and analyzed. Strains of E. coli, P. aeruginosa, S. mitis, H. influenzae, S. pneumoniae, S. aureus were used to assess the antimicrobial effect of PRF membranes prepared with the same antibiotics and compared to control PRF.

RESULTS

Vancomycin interfered with PRF formation. Gentamicin and linezolid did not change the physical properties of PRF and were released from membranes in the time intervals examined. The inhibition area analysis showed that control PRF had slight antibacterial activity against all tested microorganisms. Gentamicin-PRF had a massive antibacterial activity against all tested microorganisms. Results were similar for linezolid-PRF, except for its antibacterial activity against E. coli and P. aeruginosa that was comparable to control PRF.

CONCLUSIONS

PRF loaded with antibiotics allowed the release of antimicrobial drugs in an effective concentration. Using PRF loaded with antibiotics after oral surgery may reduce the risk of post-operative infection, replace or enhance systemic antibiotic therapy while preserving the healing properties of PRF. Further studies are needed to prove that PRF loaded with antibiotics represents a topical antibiotic delivery tool for oral surgical procedures.

Microbiome and the inflammatory pathway in peri-implant health and disease with an updated review on treatment strategies

Crestal bone preservation around the dental implant for aesthetic and functional success is widely researched and documented over a decade. Several etiological factors were put forth for crestal bone loss; of which biofilm plays a major role. Biofilm is formed by the colonization of wide spectra of bacteria inhabited around dental implants. Bacterial adherence affects the regulators of bone growth and an early intervention preserves the peri-implant bone. Primary modes of therapy stated in early literature were either prevention or treatment of infection caused by biofilm. This narrative review overviews the microbiome during different stages of peri-implant health, the mechanism of bone destruction, and the expression of the biomarkers at each stage. Microbial contamination and the associated biomarkers varied depending on the stage of peri-implant infection. The comprehensive review helps in formulating a research plan, both in diagnostics and treatment aspects in improving peri-implant health.

Evaluation of advanced platelet-rich fibrin (PRF) as a bio-carrier for ampicillin/sulbactam

OBJECTIVES

Mechanisms of wound healing are often impaired in patients with osteonecrosis of the jaw (ONJ). According to the guidelines for the treatment of this disease, early surgical intervention is indicated. However, surgery often faces complications such as wound healing disorders. The application of platelet-rich fibrin (PRF) after necrosectomy between bone and mucosa may constitute a promising approach to improve surgical results. An aspect that was not investigated until now is that PRF acts as a "bio-carrier" for antibiotics previously applied intravenously.

MATERIALS AND METHODS

We investigated the antimicrobial properties of PRF in 24 patients presenting ONJ undergoing systemic antibiosis with ampicillin/sulbactam. We measured the concentration of ampicillin/sulbactam in plasma and PRF and performed agar diffusion tests. Ampicillin/sulbactam was applied intravenously to the patient 10 minutes for blood sampling for PRF. No further incorporation of patients' blood or PRF product with antibiotic drugs was obtained. Four healthy patients served as controls.

RESULTS

Our results revealed that PRF is highly enriched with ampicillin/sulbactam that is released to the environment. The antibiotic concentration in PRF was comparable to the plasma concentration of ampicillin/sulbactam. The inhibition zone (IZ) of PRF was comparable to the standard ampicillin/sulbactam discs used in sensitivity testing.

CONCLUSIONS

The results of our study demonstrated that PRF is a reliable bio-carrier for systemic applied antibiotics and exhibits a large antimicrobial effect.

CLINICAL RELEVANCE

We describe a clinically useful feature of PRF as a bio-carrier for antibiotics. Especially when applied to poorly perfused tissues and bone such as in ONJ, the local release of antibiotics can reduce wound healing disorders like infections.

Blood cell-based drug delivery systems: a biomimetic platform for antibacterial therapy

With the rapid increase in multidrug-resistance against antibiotics, higher doses of antibiotics or more effective antibiotics are needed to treat diseases, which ultimately leads to a decrease in the body's immunity and seriously threatens human health worldwide. The efficiency of antibiotics has been a large challenge for years. To overcome this problem, many carriers are utilized for anti-bacteria, attempting to optimize the delivery of such drugs and transport them safely and directly to the site of disease. Blood cell-based drug delivery systems present several advantages as compared to polymeric delivery system. These blood cells including red blood cells (RBCs), leukocytes, platelets. The blood cells and their membranes can both be used as drug carriers to deliver antibacterial drugs. In addition, blood cells can overcome many physiological/pathological obstacles faced by nanoparticles in vivo and effectively deliver drugs to the site of the disease. In this paper, we review studies on blood cell-based delivery systems used in antibacterial therapy, and analyze different roles in antibacterial therapy, which provide basis for further study in this field.

Titanium platelet-rich fibrin (T-PRF) as high-capacity doxycycline delivery system

OBJECTIVES

Titanium platelet-rich fibrin (T-PRF), a second-generation autogenous blood concentrate with tough and thick fibrin meshwork activated by a titanium tube, was used as a drug carrier for doxycycline (Doxy) by injection. The objective of this study is to evaluate the loading capacity of T-PRF, release kinetics of doxycycline-loaded T-PRF, and its antibacterial effects against S. aureus and P. aeruginosa.

MATERIALS AND METHODS

The T-PRF and collagen were loaded with Doxy as T-PRF/Doxy and Collagen/Doxy, and their release and antibacterial activities against S. aureus and P. aeruginosa were investigated. Chemical characterization and morphological analysis were performed.

RESULTS

In comparison with collagen, approximately sevenfold more Doxy, 281 mg/g, was loaded into T-PRF. It was found that 25% of the loaded Doxy was released from T-PRF compared to only 12% from collagen within 72 h. The largest inhibition zone diameter (IZD) was observed for T-PRF/Dox with 32 ± 6 mm and 37 ± 5 mm for P. aereginosa and S. aureus, respectively. However, only 10 ± 5 mm and 10 ± 6 mm IZD were observed for bare T-PRF, and no inhibition zone was observed for the Collagen/Doxy group. A dense fibrin structure was visualized on SEM images of the T-PRF/Doxy group compared to the T-PRF group.

CONCLUSIONS

T-PRF has higher Doxy loading capacity and long-acting antibacterial effects compared to collagen. T-PRF was shown to have potential autogenous long-term drug-carrying capability for doxycycline. Also, the potential fibrinophilic properties of Doxy were observed to strengthen the structure of T-PRF.

CLINICAL RELEVANCE

T-PRF is an autogenous drug career with high loading capacity and extended antibacterial effects for doxycycline. Doxycycline molecules can be visible on T-PRF fibers. This study suggests that T-PRF/Dox could be used as a proper antibiotic delivery device in the treatments of periodontitis and peri-implantitis.

Tranexamic acid integrated into platelet-rich fibrin produces a robust and resilient antihemorrhagic biological agent: a human cohort study

OBJECTIVE

To investigate the incorporation of the antifibrinolytic agent tranexamic acid (TA) during platelet-rich fibrin (PRF) formation to produce a robust fibrin agent with procoagulation properties.

STUDY DESIGN

Blood from healthy volunteers was collected. Into 3 tubes, TA was immediately added in 1-mL, 0.4-mL, and 0.2-mL volumes, and the fourth tube was without additions. After PRF preparation, the clots were weighed in their raw (clot) and membrane forms. PRF physical properties were analyzed using a universal testing system (Instron). Protein and TA levels in the PRF were analyzed using a bicinchoninic acid assay and a ferric chloride assay, respectively.

RESULTS

The addition of TA to PRF led to a robust weight compared with sham control. PRF weight was greater in females in all tested groups. The addition of TA also led to greater resilience to tears, especially at 1-mL TA addition to the blood. Furthermore, TA addition led to a greater value of total protein within the PRF and entrapment of TA in the PRF.

CONCLUSIONS

Addition of TA to a PRF preparation leads to robust PRF with greater protein levels and the amalgamation of TA into the PRF. Such an agent may enhance the beneficial properties of PRF and attribute procoagulation properties to it.

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.

Comparison of the Postoperative Effects of Local Antibiotic versus Systemic Antibiotic with the Use of Platelet-Rich Fibrin on Impacted Mandibular Third Molar Surgery: A Randomized Split-Mouth Study

The surgery of the impacted mandibular third molar is the most frequent procedure in dentistry. The prescription of systemic antibiotics after the third molar extraction is widespread among dentists, but this is still argumentative. This study is aimed at evaluating the postoperative effects of local antibiotic mixed with platelet-rich fibrin (PRF) and a postoperative systemic antibiotic prescribed for mandibular third molar surgery. The study included 75 patients divided into a control and 4 test groups (n = 15). In the control group, only PRF was placed into the extracted socket, and no antibiotic was prescribed. In the first and third groups, PRF was applied to the socket; penicillin and clindamycin were prescribed as oral medications, respectively. In the second and fourth groups, only PRF combined with penicillin and clindamycin was applied into the socket, respectively. The outcome variables were pain, swelling, analgesic intake, and trismus. These variables were also assessed based on the first, second, third, and seventh days following the operation. Unpaired Student's t-test and Mann–Whitney U test were used for analysis. There were significant differences in the total VAS pain scores between the control and group 3 (p < 0.05), groups 1 and 2 (p < 0.01), and group 4 (p < 0.001) in ascending order. For analgesic intake, there was no significant difference for group 1 (p > 0.05). However, there were statistical differences between the control group and groups 2 and 3 (p < 0.01) and group 4 (p < 0.001). Trismus and swelling did not differ among the groups (p > 0.05). This study showed that the effects of local and systemic antibiotics with the use of PRF reduced postoperative outcomes. Moreover, local antibiotics with PRF may be a viable method to avoid the possible side effects of systemic antibiotics.

From Blood to Regenerative Tissue: How Autologous Platelet-Rich Fibrin Can Be Combined with Other Materials to Ensure Controlled Drug and Growth Factor Release

The purpose of this review is to examine the latest literature on the use of autologous platelet-rich fibrin as a drug and growth factor carrier system in maxillofacial surgery. Autologous platelet-rich fibrin (PRF) is a unique system that combines properties such as biocompatibility and biodegradability, in addition to containing growth factors and peptides that provide tissue regeneration. This opens up new horizons for the use of all beneficial ingredients in the blood sample for biomedical purposes. By itself, PRF has an unstable effect on osteogenesis: therefore, advanced approaches, including the combination of PRF with materials or drugs, are of great interest in clinics. The main advantage of drug delivery systems is that by controlling drug release, high drug concentrations locally and fewer side effects within other tissue can be achieved. This is especially important in tissues with limited blood supply, such as bone tissue compared to soft tissue. The ability of PRF to degrade naturally is considered an advantage for its use as a "warehouse" of controlled drug release systems. We are focusing on this concentrate, as it is easy to use in manipulations and can be delivered directly to the surgical site. The target audience for this review are researchers and medical doctors who are involved in the development and research of PRFs further studies. Likewise, surgeons who use PRF in their work to treat patients and who advice patients to take the medicine orally.

Biomaterials for Periodontal and Peri-Implant Regeneration

Periodontal and peri-implant regeneration is the technique that aims to restore the damaged tissue around teeth and implants. They are surrounded by a different apparatus, and according to it, the regenerative procedure can differ for both sites. During the last century, several biomaterials and biological mediators were proposed to achieve a complete restoration of the damaged tissues with less invasiveness and a tailored approach. Based on relevant systematic reviews and articles searched on PubMed, Scopus, and Cochrane databases, data regarding different biomaterials were extracted and summarized. Bone grafts of different origin, membranes for guided tissue regeneration, growth factors, and stem cells are currently the foundation of the routinary clinical practice. Moreover, a tailored approach, according to the patient and specific to the involved tooth or implant, is mandatory to achieve a better result and a reduction in patient morbidity and discomfort. The aim of this review is to summarize clinical findings and future developments regarding grafts, membranes, molecules, and emerging therapies. In conclusion, tissue engineering is constantly evolving; moreover, a tailor-made approach for each patient is essential to obtain a reliable result and the combination of several biomaterials is the elective choice in several conditions.

Clinical and radiographic effects of ascorbic acid-augmented platelet-rich fibrin versus platelet-rich fibrin alone in intra-osseous defects of stage-III periodontitis patients: a randomized controlled clinical trial

Aim

To assess platelet-rich fibrin (PRF) with ascorbic acid (AA) versus PRF in intra-osseous defects of stage-III periodontitis patients.

Methodology

Twenty stage-III/grade C periodontitis patients, with ≥ 3 mm intra-osseous defects, were randomized into test (open flap debridement (OFD)+AA/PRF; n = 10) and control (OFD+PRF; n = 10). Clinical attachment level (CAL; primary outcome), probing pocket depth (PPD), gingival recession depth (RD), full-mouth bleeding scores (FMBS), full-mouth plaque scores (FMPS), radiographic linear defect depth (RLDD) and radiographic defect bone density (RDBD) (secondary-outcomes) were examined at baseline, 3 and 6 months post-surgically.

Results

OFD+AA/PRF and OFD+PRF demonstrated significant intragroup CAL gain and PPD reduction at 3 and 6 months (p < 0.001). OFD+AA/PRF and OFD+PRF showed no differences regarding FMBS or FMPS (p > 0.05). OFD+AA/PRF demonstrated significant RD reduction of 0.90 ± 0.50 mm and 0.80 ± 0.71 mm at 3 and 6 months, while OFD+PRF showed RD reduction of 0.10 ± 0.77 mm at 3 months, with an RD-increase of 0.20 ± 0.82 mm at 6 months (p < 0.05). OFD+AA/PRF and OFD+PRF demonstrated significant RLDD reduction (2.29 ± 0.61 mm and 1.63 ± 0.46 mm; p < 0.05) and RDBD-increase (14.61 ± 5.39% and 12.58 ± 5.03%; p > 0.05). Stepwise linear regression analysis showed that baseline RLDD and FMBS at 6 months were significant predictors of CAL reduction (p < 0.001).

Conclusions

OFD+PRF with/without AA significantly improved periodontal parameters 6 months post-surgically. Augmenting PRF with AA additionally enhanced gingival tissue gain and radiographic defect fill.

Clinical relevance

PRF, with or without AA, could significantly improve periodontal parameters. Supplementing PRF with AA could additionally augment radiographic linear defect fill and reduce gingival recession depth.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00784-021-03929-1.

Methodological variations affect the release of VEGF in vitro and fibrinolysis' time from platelet concentrates

Blood Concentrates (BCs) are autologous non-transfusional therapeutical preparations with biological properties applied in tissue regeneration. These BCs differ in the preparation method, in fibrin network architecture, growth factors release as well as in platelet/cell content. Methodological changes result in distinct matrices that can compromise their clinical effectiveness. The present study evaluated the influence of different g-forces and types of tubes in the release of vascular endothelial growth factor (VEGF) from platelet-rich fibrin (PRF) as a function of time. The PRF-like samples were obtained with three g-forces (200, 400, and 800 x g) for 10 minutes in pure glass tubes or in polystyrene-clot activator tubes. Scanning and Transmission electron microscopy was used to morphometric analyzes of PRF’s specimens and flow cytometry was used to quantify VEGF slow release until 7 days. Our results showed that platelets were intact and adhered to the fibrin network, emitting pseudopods and in degranulation. The fibrin network was rough and twisted with exosomic granulations impregnated on its surface. An increase in the concentration of VEGF in the PRF supernatant was observed until 7 days for all g forces (200, 400 or 800 xg), with the highest concentrations observed with 200 x g, in both tubes, glass or plastic. Morphological analyzes showed a reduction in the diameter of the PRF fibers after 7 days. Our results showed that g-force interferes with the shape of the fibrin network in the PRF, as well as affect the release of VEGF stored into platelets. This finding may be useful in applying PRF to skin lesions, in which the rapid release of growth factors can favor the tissue repair process. Our observations point to a greater clarification on the methodological variations related to obtaining PRF matrices, as they can generate products with different characteristics and degrees of effectiveness in specific applications.