Use of Leukocyte-and Platelet-Rich Fibrin for Bone Regeneration: A Systematic Review

Introduction: Leukocyte- and platelet- rich fibrin (L-PRF) is a fibrin matrix in which the platelet cytokines, growth factors and cells are trapped and this material has been recruited in reconstruction of various defects. The aim of this study was to systematically review of the published data on the effectiveness of using L-PRF on regeneration of bone defects in oral and maxillofacial surgeries. Materials and Methods: Medline and Cochrane Central databases were searched for related articles up to and including August 2015. Being English, having ≥ four weeks follow-up, and clinical, radiographic, histological and histomorphometric assessments were the inclusion criteria. Results: Twenty-four animal studies and 45 human trials were included that reported the rate of new bone formation (NBF). Also, 38 human reports with low levels of evidence to list evaluating various applications of L-PRF in oral and maxillofacial reconstructions were assessed. Using L-PRF either solely or mixed in human trials was evaluated and divided into six groups of sinus floor augmentation and guided bone regeneration (GBR) technique, socket preservation, periodontal intra-bony defects (PID)  regeneration, peri-apical and endo-periodontal defects treatment, peri-implant bone regeneration and treatment of bisphosphonate-related osteonecrosis of the jaw (BRONJ). Moreover, other uses of L-PRF with bone regeneration purposes in oral and maxillofacial surgeries were discussed. Conclusion: As a consequence, although L-PRF either solely or mixed showed challengeable outcomes in animal studies, it was shown to be effective used to accelerate and enhance new bone formation in human studies. However, future clinical trials in some treatment areas are needed with larger sample sizes and long follow-ups to arrive at an evidence-based conclusion.

Apical Extrusion of Debris after Canal Preparation with Hand-Files Used Manually or Installed on Reciprocating Air-Driven Handpiece in Straight and Curved Canals

Introduction: Apical debris extrusion (DE) subsequent to root canal instrumentation, is one of the most important causes of endodontic flare-ups. The aim of this study was to compare the amount of DE after root canal instrumentation using nickel-titanium (NiTi) hand files with step-back manual technique or installed on reciprocating handpiece. Methods and Materials: This study was conducted on mesiobuccal (MB) roots of extracted maxillary first molars (n=20) and roots of mandibular premolars (n=20) that were randomly divided into two groups (n=20) according to the armamentarium used for canal preparation (air-driven reciprocating handpiece or hand instrumentation). In each group, the MB and premolar roots were prepared with the main apical sizes of 35 and 40, respectively. The extruded debris were collected and weighed. Finally, the mean dry weights were compared using ANOVA and t-test, and Tukey’s Multiple Comparisons Procedures were used to determine the significant differences in amounts of DE. The level of significance was set at 0.05. Results: Regardless of the type of teeth, the mean values of DE, were significantly lower in the handpiece group (P<0.0001). In addition, significantly lower amounts of DE was observed in premolars in similar group (P<0.001). However, this difference was not significant in MB roots of molars (P=0.20). Conclusion: Root canal preparation with reciprocating handpiece can lead to significantly lower debris extrusion than the manual step-back technique. In handpiece-prepared canals, the amount of extruded debris was significantly lower in premolar teeth.Keywords: Apical; Apical Extrusion; Debris Extrusion; NiTi Files; Reciprocation; Step-Back Techniqu

Characterization of Wet-electrospun Poly (ε-caprolactone)/Poly (L-lactic) Acid with Calcium Phosphates Coated with Chitosan for Bone Engineering

Introduction: Remarkable advances have been made in the development of scaffolds with favorable characteristics for bone tissue engineering using different techniques. Recently, electrospinning process for fabrication of fibrous matrices have gained popularity, mainly because of structural similarity to the extracellular matrix. In this study, the influence of in situ formation of calcium phosphates (CP) stabled with chitosan (CT) layer on the physicochemical properties of the wet-electrospun poly (ε-caprolactone)/poly (L-lactic) acid (PCL/PLLA) scaffolds was evaluated. Materials and Methods: To prepare three-dimensional (3D) fibrous scaffold, PCL/PLLA 10% (w/v) blend was fabricated via wet-electrospinning technique. The fabricated scaffolds were characterized regarding morphology, porosity, hydrophilicity and mechanical strength using scanning electron microscopy (SEM), liquid displacement technique, contact angle measurement and mechanical tests, respectively. Moreover, cell adhesion and viability of human adipose-derived stem cells (hASCs) seeded on the scaffolds were investigated using SEM, MTT assay and DAPI staining. Results: Wet-electrospun fibers displayed random, dispersive and non-woven morphology. Porosity of the fabricated scaffolds was 80% and CT coating improved the water contact angle value. In vitro seeding of ADSCs on PCL/PLLA/CP+CT demonstrated enhanced cell proliferation and attachment compared to the PCL/PLLA blend. Porosity, wettability, mechanical properties and biocompatibility of the PCL/PLLA scaffolds have significantly influenced by both in situ formation of CP and CT coating. Conclusion: The results indicated that the PCL/PLLA scaffold spun into water/ethanol modified with NaOH (pH~10) coagulation bath with in situ surface formation of CP and CT coating can be a candidate scaffold for bone tissue engineering

Development of PLGA-coated β-TCP scaffolds containing VEGF for bone tissue engineering

Bone tissue engineering is sought to apply strategies for bone defects healing without limitations and short-comings of using either bone autografts or allografts and xenografts. The aim of this study was to fabricate a thin layer poly(lactic-co-glycolic) acid (PLGA) coated beta-tricalcium phosphate (β-TCP) scaffold with sustained release of vascular endothelial growth factor (VEGF). PLGA coating increased compressive strength of the β-TCP scaffolds significantly. For in vitro evaluations, canine mesenchymal stem cells (cMSCs) and canine endothelial progenitor cells (cEPCs) were isolated and characterized. Cell proliferation and attachment were demonstrated and the rate of cells proliferation on the VEGF released scaffold was significantly more than compared to the scaffolds with no VEGF loading. A significant increase in expression of COL1 and RUNX2 was indicated in the scaffolds loaded with VEGF and MSCs compared to the other groups. Consequently, PLGA coated β-TCP scaffold with sustained and localized release of VEGF showed favourable results for bone regeneration in vitro, and this scaffold has the potential to use as a drug delivery device in the future

Biocompatibility of Portland Cement Modified with Titanium Oxide and Calcium Chloride in a Rat Model

Introduction: The aim of the present study was to evaluate the biocompatibility of two modified formulations of Portland cement (PC) mixed with either titanium oxide or both titanium oxide and calcium chloride. Methods and Materials: Polyethylene tubes were filled with modified PCs or Angelus MTA as the control; the tubes were then implanted in 28 Wistar rats subcutaneously. One tube was left empty as a negative control in each rat. Histologic samples were taken after 7, 15, 30 and 60 days. Sections were assessed histologically for inflammatory responses and presence of fibrous capsule and granulation tissue formation. Data were analyzed using the Fisher’s exact and Kruskal-Wallis tests. Result: PC mixed with titanium oxide showed the highest mean scores of inflammation compared with others. There was no statistically significant difference in the mean inflammatory grades between all groups in each of the understudy time intervals. Conclusion: The results showed favorable biocompatibility of these modified PC mixed with calcium chloride and titanium oxide.Keywords: Biocompatibility; Mineral Trioxide Aggregate; Portland Cemen

Critical-Sized Bone Defects Regeneration Using a Bone-Inspired 3D Bilayer Collagen Membrane in Combination with Leukocyte and Platelet-Rich Fibrin Membrane (L-PRF): An \u3cem\u3eIn Vivo\u3c/em\u3e Study

Objectives We aim to develop a 3D-bilayer collagen (COL) membrane reinforced with nano beta-tricalcium-phosphate (nβ-TCP) particles and to evaluate its bone regeneration in combination with leukocyte-platelet-rich fibrin (L-PRF) in vivo. Background data L-PRF has exhibited promising results as a cell carrier in bone regeneration in a number of clinical studies, however there are some studies that did not confirm the positive results of L-PRF application. Methods Mechanical & physiochemical characteristics of the COL/nβ-TCP membrane (1/2 & 1/4) were tested. Proliferation and osteogenic differentiation of seeded cells on bilayer collagen/nβ-TCP thick membrane was examined. Then, critical-sized calvarial defects in 8 white New Zealand rabbits were filled with either Col, Col/nβ-TCP, Col/nβ-TCP combined with L-PRF membrane, or left empty. New bone formation (NBF) was measured histomorphometrically 4 & 8 weeks postoperatively. Results Compressive modulus increases while porosity decreases with higher β-TCP concentrations. Mechanical properties improve, with 89 % porosity (pore size ∼100 μm) in the bilayer-collagen/nβ-TCP membrane. The bilayer design also enhances the proliferation and ALP activity. In vivo study shows no significant difference among test groups at 4 weeks, but Col/nβ-TCP + L-PRF demonstrates more NBF compared to others (P \u3c 0.05) after 8 weeks. Conclusion The bilayer-collagen/nβ-TCP thick membrane shows promising physiochemical in vitro results and significant NBF, as ¾ of the defect is filled with lamellar bone when combined with L-PRF membrane

Advances in Hydrogel Bioprinting for Bone Tissue Engineering

Bone regeneration is a complex process involving the orchestration of multiple cellular and molecular events. In recent years, significant interest has emerged in utilizing three-dimensional (3D) printed hydrogels for bone tissue engineering, owing to their potential in mimicking the natural extracellular matrix and providing a platform for cell growth and differentiation. The use of bioprinted hydrogels for bone regeneration has garnered attention due to its potential in addressing critical-sized bone defects