Dimensionally stable and bioactive membrane for guided bone regeneration: An in vitro study

Advances in guided bone regeneration membranes: a comprehensive review of materials and techniques

Guided tissue/bone regeneration (GTR/GBR) is a widely used technique in dentistry to facilitate the regeneration of damaged bone and tissue, which involves guiding materials that eventually degrade, allowing newly created tissue to take its place. This comprehensive review the evolution of biomaterials for guided bone regeneration that showcases a progressive shift from non-resorbable to highly biocompatible and bioactive materials, allowing for more effective and predictable bone regeneration. The evolution of biomaterials for guided bone regeneration GTR/GBR has marked a significant progression in regenerative dentistry and maxillofacial surgery. Biomaterials used in GBR have evolved over time to enhance biocompatibility, bioactivity, and efficacy in promoting bone growth and integration. This review also probes into several promising fabrication techniques like electrospinning and latest 3D printing fabrication techniques, which have shown potential in enhancing tissue and bone regeneration processes. Further, the challenges and future direction of GTR/GBR are explored and discussed.

Guided Tissue and Bone Regeneration Membranes: A Review of Biomaterials and Techniques for Periodontal Treatments

This comprehensive review provides an in-depth analysis of the use of biomaterials in the processes of guided tissue and bone regeneration, and their indispensable role in dental therapeutic interventions. These interventions serve the critical function of restoring both structural integrity and functionality to the dentition that has been lost or damaged. The basis for this review is laid through the exploration of various relevant scientific databases such as Scopus, PubMed, Web of science and MEDLINE. From a meticulous selection, relevant literature was chosen. This review commences by examining the different types of membranes used in guided bone regeneration procedures and the spectrum of biomaterials employed in these operations. It then explores the manufacturing technologies for the scaffold, delving into their significant impact on tissue and bone regenerations. At the core of this review is the method of guided bone regeneration, which is a crucial technique for counteracting bone loss induced by tooth extraction or periodontal disease. The discussion advances by underscoring the latest innovations and strategies in the field of tissue regeneration. One key observation is the critical role that membranes play in guided reconstruction; they serve as a barrier, preventing the entry of non-ossifying cells, thereby promoting the successful growth and regeneration of bone and tissue. By reviewing the existing literature on biomaterials, membranes, and scaffold manufacturing technologies, this paper illustrates the vast potential for innovation and growth within the field of dental therapeutic interventions, particularly in guided tissue and bone regeneration.

Nanoscale β-TCP-Laden GelMA/PCL Composite Membrane for Guided Bone Regeneration

Major advances in the field of periodontal tissue engineering have favored the fabrication of biodegradable membranes with tunable physical and biological properties for guided bone regeneration (GBR). Herein, we engineered innovative nanoscale beta-tricalcium phosphate (β-TCP)-laden gelatin methacryloyl/polycaprolactone (GelMA/PCL-TCP) photocrosslinkable composite fibrous membranes via electrospinning. Chemo-morphological findings showed that the composite microfibers had a uniform porous network and β-TCP particles successfully integrated within the fibers. Compared with pure PCL and GelMA/PCL, GelMA/PCL-TCP membranes led to increased cell attachment, proliferation, mineralization, and osteogenic gene expression in alveolar bone-derived mesenchymal stem cells (aBMSCs). Moreover, our GelMA/PCL-TCP membrane was able to promote robust bone regeneration in rat calvarial critical-size defects, showing remarkable osteogenesis compared to PCL and GelMA/PCL groups. Altogether, the GelMA/PCL-TCP composite fibrous membrane promoted osteogenic differentiation of aBMSCs in vitro and pronounced bone formation in vivo. Our data confirmed that the electrospun GelMA/PCL-TCP composite has a strong potential as a promising membrane for guided bone regeneration.

Bioglass/collagen scaffolds combined with bone marrow stromal cells on bone healing in an experimental model in cranial defects in rats

This study aimed to develop bone regenerative therapeutic strategies, based on the addition of bone marrow stromal cells (BMSC) on bioglass/collagen (BG/COL) scaffolds. For this purpose, an in vivo study was conducted using tissue response of the BG/COL scaffolds combined with BMSC in a critical-size defects. Wistar rats were submitted to the surgical procedure to perform the cranial critical size bone defects and distributed in four groups (20 animals per group): Control Group (CG) (rats submitted to the cranial bone defect surgery without treatment), Bioglass Group (BG) (rats treated with BG), BG/COL Group (rats treated with BG/COL) and Bioglass/Collagen and BMSC Group (BG/COL/BMSC) (rats treated with BG/COL scaffolds enriched with BMSCs). Animals were euthanized 15 and 30 days after surgery. Scanning electron microscopy, histopathological and immunohistochemistry analysis were used. SEM analysis demonstrated that porous scaffolds were obtained, and Col fibers were successfully impregnated to BG matrices. The implantation of the BMSC on BG/COL based scaffolds was effective in stimulating newly bone formation and produced an increased immunoexpression of markers related to the bone repair. These results highlight the potential of BG/COL scaffolds and BMSCs to be used as a therapeutic approach for bone regeneration.

Asymmetric resorbable-based dental barrier membrane for periodontal guided tissue regeneration and guided bone regeneration: A review

Guided tissue regeneration (GTR) and guided bone regeneration (GBR) are two common dental regenerative treatments targeted at reconstructing damaged periodontal tissue and bone caused by periodontitis. During GTR/GBR treatment, a barrier membrane is placed in the interface between the soft tissue and the periodontal defect to inhibit soft tissue ingrowth and creating a space for the infiltration of slow-growing bone cells into the defect site. Recently, asymmetric resorbable-based barrier membrane has received a considerable attention as a new generation of GTR/GBR membrane. Despite numerous literatures about asymmetric-based membrane that had been published, there is lacks comprehensive review on asymmetric barrier membrane that particularly highlight the importance of membrane structure for periodontal regeneration. In this review, we systematically cover the latest development and advancement of various kinds of asymmetric barrier membranes used in periodontal GTR/GBR application. Herein, the ideal requirements for constructing a barrier membrane as well as the rationale behind the asymmetric design, are firstly presented. Various innovative methods used in fabricating asymmetric barrier membrane are being further discussed. Subsequently, the application and evaluation of various types of asymmetric barrier membrane used for GTR/GBR are compiled and extensively reviewed based on the recent literatures reported. Based on the existing gap in this field, the future research directions of asymmetric resorbable-based barrier membrane such as its combination potential with bone grafts, are also presented.

Advances in Modification Methods Based on Biodegradable Membranes in Guided Bone/Tissue Regeneration: A Review

Guided tissue/bone regeneration (GTR/GBR) is commonly applied in dentistry to aid in the regeneration of bone/tissue at a defective location, where the assistive material eventually degrades to be substituted with newly produced tissue. Membranes separate the rapidly propagating soft tissue from the slow-growing bone tissue for optimal tissue regeneration results. A broad membrane exposure area, biocompatibility, hardness, ductility, cell occlusion, membrane void ratio, tissue integration, and clinical manageability are essential functional properties of a GTR/GBR membrane, although no single modern membrane conforms to all of the necessary characteristics. This review considers ongoing bone/tissue regeneration engineering research and the GTR/GBR materials described in this review fulfill all of the basic ISO requirements for human use, as determined through risk analysis and rigorous testing. Novel modified materials are in the early stages of development and could be classified as synthetic polymer membranes, biological extraction synthetic polymer membranes, or metal membranes. Cell attachment, proliferation, and subsequent tissue development are influenced by the physical features of GTR/GBR membrane materials, including pore size, porosity, and mechanical strength. According to the latest advances, key attributes of nanofillers introduced into a polymer matrix include suitable surface area, better mechanical capacity, and stability, which enhances cell adhesion, proliferation, and differentiation. Therefore, it is essential to construct a bionic membrane that satisfies the requirements for the mechanical barrier, the degradation rate, osteogenesis, and clinical operability.

Personalized and Defect-Specific Antibiotic-Laden Scaffolds for Periodontal Infection Ablation

Periodontitis compromises the integrity and function of tooth-supporting structures. Although therapeutic approaches have been offered, predictable regeneration of periodontal tissues remains intangible, particularly in anatomically complex defects. In this work, personalized and defect-specific antibiotic-laden polymeric scaffolds containing metronidazole (MET), tetracycline (TCH), or their combination (MET/TCH) were created via electrospinning. An initial screening of the synthesized fibers comprising chemo-morphological analyses, cytocompatibility assessment, and antimicrobial validation against periodontopathogens was accomplished to determine the cell-friendly and anti-infective nature of the scaffolds. According to the cytocompatibility and antimicrobial data, the 1:3 MET/TCH formulation was used to obtain three-dimensional defect-specific scaffolds to treat periodontally compromised three-wall osseous defects in rats. Inflammatory cell response and new bone formation were assessed by histology. Micro-computerized tomography was performed to assess bone loss in the furcation area at 2 and 6 weeks post implantation. Chemo-morphological and cell compatibility analyses confirmed the synthesis of cytocompatible antibiotic-laden fibers with antimicrobial action. Importantly, the 1:3 MET/TCH defect-specific scaffolds led to increased new bone formation, lower bone loss, and reduced inflammatory response when compared to antibiotic-free scaffolds. Altogether, our results suggest that the fabrication of defect-specific antibiotic-laden scaffolds holds great potential toward the development of personalized (i.e., patient-specific medication) scaffolds to ablate infection while affording regenerative properties.

Innovations in Craniofacial Bone and Periodontal Tissue Engineering - From Electrospinning to Converged Biofabrication

From a materials perspective, the pillars for the development of clinically translatable scaffold-based strategies for craniomaxillofacial (CMF) bone and periodontal regeneration have included electrospinning and 3D printing (biofabrication) technologies. Here, we offer a detailed analysis of the latest innovations in 3D (bio)printing strategies for CMF bone and periodontal regeneration and provide future directions envisioning the development of advanced 3D architectures for successful clinical translation. First, the principles of electrospinning applied to the generation of biodegradable scaffolds are discussed. Next, we present on extrusion-based 3D printing technologies with a focus on creating scaffolds with improved regenerative capacity. In addition, we offer a critical appraisal on 3D (bio)printing and multitechnology convergence to enable the reconstruction of CMF bones and periodontal tissues. As a future outlook, we highlight future directions associated with the utilization of complementary biomaterials and (bio)fabrication technologies for effective translation of personalized and functional scaffolds into the clinics.

Development of Zoledronic Acid Containing Biomaterials for Enhanced Guided Bone Regeneration

In recent years, biomaterial-based treatments, also called guided bone regeneration (GBR), which aim to establish a bone regeneration site and prevent the migration of gingival connective tissue and / or peripheral epithelium through the defective area during periodontal surgical procedures have come to the fore. In this report, we have developed a nanoparticle bearing thermosensitive in situ gel formulation of Pluronic F127 and poly(D,L-lactic acid) based membrane to reveal their utilization at GBR by in-vivo applications. In addition, the encouragement of the bone formation in defect area via inhibition of osteoclastic activity is intended by fabrication these biodegradable biomaterials at a lowered Zoledronic Acid (ZA) dose. Both of the developed materials remained stable under specified stability conditions (25 °C, 6 months) and provided the extended release profile of ZA. The in-vivo efficacy of nanoparticle bearing in situ gel formulation, membrane formulation and simultaneous application for guided bone regeneration was investigated in New Zealand female rabbits with a critical size defect of 0.5 × 0.5 cm in the tibia bone for eight weeks. Based on the histopathological findings, lamellar bone and primarily woven bone formations were observed after 8 weeks of post-implantation of both formulations, while fibrosis was detected only in the untreated group. Lamellar bone growth was remarkably achieved just four weeks after the simultaneous application of formulations. Consequently, the simultaneous application of ZA-membrane and ZA-nanoparticles loaded in-situ gel formulations offers enhanced and faster GBR therapy alternatives.

In Vitro Degradation of Plasticized PLA Electrospun Fiber Mats: Morphological, Thermal and Crystalline Evolution

In the present work, fiber mats of poly(lactic acid), PLA, plasticized by different amounts of oligomer lactic acid, OLA, were obtained by electrospinning in order to investigate their long term hydrolytic degradation. This was performed in a simulated body fluid for up to 352 days, until the complete degradation of the samples is reached. The evolution of the plasticized electrospun mats was followed in terms of morphological, thermal, chemical and crystalline changes. Mass variation and water uptake of PLA-based electrospun mats, together with pH stability of the immersion media, were also studied during the in vitro test. The results showed that the addition of OLA increases the hydrolytic degradation rate of PLA electrospun fiber mats. Moreover, by adding different amounts of OLA, the time of degradation of the electrospun fiber mats can be modulated over the course of a year. Effectively, by increasing the amount of OLA, the diameter of the electrospun fibers decreases more rapidly during degradation. On the other hand, the degree of crystallinity and the dimension of the α crystals of the electrospun fiber mats are highly affected not only by the presence but also by the amount of OLA during the whole process.

Evaluation of 1-Ethyl-3-(3-Dimethylaminopropyl) Carbodiimide Cross-Linked Collagen Membranes for Guided Bone Regeneration in Beagle Dogs

The purpose of this study was to evaluate the bone regeneration efficacy of an 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC)-cross-linked collagen membrane for guided bone regeneration (GBR). A non-cross-linked collagen membrane (Control group), and an EDC-cross-linked collagen membrane (Test group) were used in this study. In vitro, mechanical, and degradation testing and cell studies were performed. In the animal study, 36 artificial bone defects were formed in the mandibles of six beagles. Implants were inserted at the time of bone grafting, and membranes were assigned randomly. Eight weeks later, animals were sacrificed, micro-computed tomography was performed, and hematoxylin-eosin stained specimens were prepared. Physical properties (tensile strength and enzymatic degradation rate) were better in the Test group than in the Control group. No inflammation or membrane collapse was observed in either group, and bone volumes (%) in defects around implants were similar in the two groups (p > 0.05). The results of new bone areas (%) analysis also showed similar values in the two groups (p > 0.05). Therefore, it can be concluded that cross-linking the collagen membranes with EDC is the method of enhancing the physical properties (tensile strength and enzymatic degradation) of the collagen membranes without risk of toxicity.

Guided bone regeneration by the development of alendronate sodium loaded in-situ gel and membrane formulations

Biocompatible materials applied in guided bone regeneration are needed to prevent leakage caused by the invasion of peripheral epithelium. (2.1) The aim of this study is to develop a thermosensitive in situ gel system containing alendronate sodium loaded PLGA nanoparticles and alendronate sodium loaded membranes for guided bone regeneration. Thermosensitive Pluronic F127 gel system was preferred to prevent soft tissue migration to the defect site and prolong the residence time of the nanoparticles in this region. In situ gel system was combined with membrane formulation to enhance bone regenaration activity. Efficacy of combination system was investigated by implanting in 0.5 × 0.5 cm critical size defect in tibia of New Zealand female rabbits. According to the histopathological results, fibroblast formations were found at defect area after 6 weeks of post implantation. In contrast, treatment with the combination of in-situ gel containing nanoparticles with membrane provided woven bone formation with mature bone after 4 weeks of post implantation. As a results, the combination of in-situ gel formulation containing alendronate sodium-loaded nanoparticles with membrane formulation could be effectively applided for guided bone regeneration.

Composite Membranes of Poly(ε-caprolactone) with Bisphosphonate-Loaded Bioactive Glasses for Potential Bone Tissue Engineering Applications

Poly(ε-caprolactone) (PCL) is a bioresorbable synthetic polyester with numerous biomedical applications. PCL membranes show great potential in guided tissue regeneration because they are biocompatible, occlusive and space maintaining, but lack osteoconductivity. Therefore, two different types of mesoporous bioactive glasses (SiO2-CaO-P2O5 and SiO2-SrO-P2O5) were synthesized and incorporated in PCL thin membranes by spin coating. To enhance the osteogenic effect of resulting membranes, the bioglasses were loaded with the bisphosphonate drug ibandronate prior to their incorporation in the polymeric matrix. The effect of the composition of the bioglasses as well as the presence of absorbed ibandronate on the physicochemical, cell attachment and differentiation properties of the PCL membranes was evaluated. Both fillers led to a decrease of the crystallinity of PCL, along with an increase in its hydrophilicity and a noticeable increase in its bioactivity. Bioactivity was further increased in the presence of a Sr substituted bioglass loaded with ibandronate. The membranes exhibited excellent biocompatibility upon estimation of their cytotoxicity on Wharton's Jelly Mesenchymal Stromal Cells (WJ-SCs), while they presented higher osteogenic potential in comparison with neat PCL after WJ-SCs induced differentiation towards bone cells, which was enhanced by a possible synergistic effect of Sr and ibandronate.

A Novel Bilayer Polycaprolactone Membrane for Guided Bone Regeneration: Combining Electrospinning and Emulsion Templating

Guided bone regeneration is a common dental implant treatment where a barrier membrane (BM) is used between epithelial tissue and bone or bone graft to prevent the invasion of the fast-proliferating epithelial cells into the defect site to be able to preserve a space for infiltration of slower-growing bone cells into the periodontal defect site. In this study, a bilayer polycaprolactone (PCL) BM was developed by combining electrospinning and emulsion templating techniques. First, a 250 µm thick polymerised high internal phase emulsion (polyHIPE) made of photocurable PCL was manufactured and treated with air plasma, which was shown to enhance the cellular infiltration. Then, four solvent compositions were investigated to find the best composition for electrospinning a nanofibrous PCL barrier layer on PCL polyHIPE. The biocompatibility and the barrier properties of the electrospun layer were demonstrated over four weeks in vitro by histological staining. Following in vitro assessment of cell viability and cell migration, cell infiltration and the potential of PCL polyHIPE for supporting blood vessel ingrowth were further investigated using an ex-ovo chick chorioallantoic membrane assay. Our results demonstrated that the nanofibrous PCL electrospun layer was capable of limiting cell infiltration for at least four weeks, while PCL polyHIPE supported cell infiltration, calcium and mineral deposition of bone cells, and blood vessel ingrowth through pores.

[Research progress on the modification of guided bone regeneration membranes]

Guided bone regeneration (GBR) is an important technique to solve bone defect problems. In this technique, GBR barrier membranes play an irreplaceable role. GBR membranes can act as a barrier protecting fibroblasts from bone defects and promote osteoblast adhesion and proliferation, leading to bone regeneration. GBR barrier membranes should be enhanced because of the disadvantages of collagen membranes, which are extensively applied to the field of GBR. Therefore, various efforts have been devoted to modifying the antibacterial and osteogenic properties of GBR barrier membranes and developing novel materials. This article reviews the research advancements on the modification of GBR barrier membranes and discover future directions for the development of GBR barrier membranes to provide a reference for bone tissue engi-neering and repair.

Histologic, Histomorphometric, and Osteogenesis Comparative Study of a Novel Fabricated Nanocomposite Membrane Versus Cytoplast Membrane

PURPOSE

The present study compared the in vivo efficacy of a novel synthesized polycaprolactone (PCL)/polyethylene glycol (PEG)/bioactive glass (BG) nanocomposite membrane versus a cytoplast (Cy) membrane in terms of the average percentage of new bone formation and inflammation levels.

MATERIALS AND METHODS

In the present interventional animal study, 12 male New Zealand rabbits were tested. In the parietal bone of the rabbits, 24 defects were prepared (2 defects for each rabbit), which were divided into 3 equal groups (Cy, PCL, and control). Each rabbit's calvarial bone was prepared for the histologic and histomorphometric survey. The amount of regenerated bone (ie, length, area, percentage), necrosis rate, fibrosis (fibrosis plus and percentage), and inflammation in the standard defects of parietal bone in the rabbits were examined and compared after 10 weeks.

RESULTS

A significant difference was found between the Cy and PCL groups regarding the mean area and thickness of the bone. We also found a significant difference in the bone length, area, and percentage formed between PCL and control groups. Also, the rate of fibrous tissue formation was significantly different statistically between the PCL and control groups. The results showed the influence of the PCL membrane in generating more bone and less fibrous tissue. In all 3 groups, negligible inflammation and no necrosis was observed.

CONCLUSIONS

The results of the present study have shown that combining PCL, PEG, and BGs could be promising for bone regeneration in jaw defects, around dental implants, and in oral and maxillofacial defects.

GBR membrane of novel poly (butylene succinate-co-glycolate) co-polyester co-polymer for periodontal application

In periodontics, osteoconductive biodegradable guided bone regeneration (GBR) membranes with acceptable physico-mechanical properties are required to fix alveolar bone defects. The objectives of the present study were to produce and characterize a novel co-polyester—poly (butylene succinate-co-glycolate) (PBSGL), and fabricate a PBSGL membrane by electrospinning. We then aimed to evaluate the in vitro effect of the glycolate ratio on the biocompatibility and osteogenic differentiation of mesenchymal stem cells (MSCs), and evaluate in vivo bone regeneration using these membranes in rabbit calvarial defects by histology. Increasing the glycolate ratio of electrospun PBSGL membranes resulted in better cell attachment, greater cell metabolic activity, and enhanced osteogenic potential at both transcriptional and translational levels. Histologic and histomorphometric evaluations revealed further that bone defects covered with fibers of higher glycolate ratios showed more bone formation, with no adverse inflammatory response. These results suggest that novel PBSGL electrospun nanofibers show great promise as GBR membranes for bone regeneration.

Electrospun F18 Bioactive Glass/PCL-Poly (ε-caprolactone)-Membrane for Guided Tissue Regeneration

Barrier membranes that are used for guided tissue regeneration (GTR) therapy usually lack bioactivity and the capability to promote new bone tissue formation. However, the incorporation of an osteogenic agent into polymeric membranes seems to be the most assertive strategy to enhance their regenerative potential. Here, the manufacturing of composite electrospun membranes made of poly (ε-caprolactone) (PCL) and particles of a novel bioactive glass composition (F18) is described. The membranes were mechanically and biologically tested with tensile strength tests and tissue culture with MG-63 osteoblast-like cell line, respectively. The PCL-F18 composite membranes demonstrated no increased cytotoxicity and an enhanced osteogenic potential when compared to pure PCL membranes. Moreover, the addition of the bioactive phase increased the membrane tensile strength. These preliminary results suggested that these new membranes can be a strong candidate for small bone injuries treatment by GTR technique.

Tetracycline-incorporated polymer nanofibers as a potential dental implant surface modifier

This study investigated the antimicrobial and osteogenic properties of titanium (Ti) disks superficially modified with tetracycline (TCH)-incorporated polymer nanofibers. The experiments were carried out in two phases. The first phase dealt with the synthesis and characterization (i.e., morphology, mechanical strength, drug release, antimicrobial activity, and cytocompatibility) of TCH-incorporated fibers. The second phase was dedicated to evaluating both the antimicrobial and murine-derived osteoprecursor cell (MC3T3-E1) response of Ti-modified with TCH-incorporated fibers. TCH was successfully incorporated into the submicron-sized and cytocompatible fibers. All TCH-incorporated mats presented significant antimicrobial activity against periodontal pathogens. The antimicrobial potential of the TCH-incorporated fibers-modified Ti was influenced by both the TCH concentration and bacteria tested. At days 5 and 7, a significant increase in MC3T3-E1 cell number was observed for TCH-incorporated nanofibers-modified Ti disks when compared to that of TCH-free nanofibers-modified Ti-disks and bare Ti. A significant increase in alkaline phosphatase (ALP) levels on the Ti disks modified with TCH-incorporated nanofiber on days 7 and 14 was seen, suggesting that the proposed surface promotes early osteogenic differentiation. Collectively, the data suggest that TCH-incorporated nanofibers could function as an antimicrobial surface modifier and osteogenic inducer for Ti dental implants. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2085-2092, 2017.

Participation of MicroRNA-34a and RANKL on bone repair induced by poly(vinylidene-trifluoroethylene)/barium titanate membrane

The poly(vinylidene-trifluoroethylene)/barium titanate (PVDF) membrane enhances in vitro osteoblast differentiation and in vivo bone repair. Here, we hypothesized that this higher bone repair could be also due to bone resorption inhibition mediated by a microRNA (miR)/RANKL circuit. To test our hypothesis, the large-scale miR expression of bone tissue grown on PVDF and polytetrafluoroethylene (PTFE) membranes was evaluated to identify potential RANKL-targeted miRs modulated by PVDF. The animal model used was rat calvarial defects implanted with either PVDF or PTFE. At 4 and 8 weeks, the bone tissue grown on membranes was submitted to a large-scale analysis of miRs by microarray. The expression of miR-34a and some of its targets, including RANKL, were evaluated by real-time polimerase chain reaction and osteoclast activity was detected by tartrate-resistant acid phosphatase (TRAP) staining. Among more than 250 miRs, twelve, including miR-34a, were simultaneously higher expressed (≥2 fold) at 4 and 8 weeks on PVDF. The higher expression of miR-34a was concomitant with a reduced expression of all its evaluated targets, including RANKL. Additionally, more TRAP-positive cells were observed in bone tissue grown on PTFE compared with PVDF in both time points. In conclusion, our results suggest that the higher bone formation induced by PVDF could be, at least in part, triggered by a miR-34a increase and RANKL decrease, which may inhibit osteoclast differentiation and activity, and bone resorption.

Biodegradable Polymer Membranes Applied in Guided Bone/Tissue Regeneration: A Review

Polymer membranes have been widely used in guided tissue regeneration (GTR) and guided bone regeneration (GBR). In this review, various commercially available membranes are described. Much attention is paid to the recent development of biodegradable polymers applied in GTR and GBR, and the important issues of biodegradable polymeric membranes, including their classification, latest experimental research and clinical applications, as well as their main challenges are addressed. Herein, natural polymers, synthetic polymers and their blends are all introduced. Pure polymer membranes are biodegradable and biocompatible, but they lack special properties such as antibacterial properties, osteoconductivity, and thus polymer membranes loaded with functional materials such as antibacterial agents and growth factors show many more advantages and have also been introduced in this review. Despite there still being complaints about polymer membranes, such as their low mechanical properties, uncontrollable degradation speed and some other drawbacks, these problems will undoubtedly be conquered and biodegradable polymers will have more applications in GTR and GBR.

Multifunctional Chitosan-45S5 Bioactive Glass-Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) Microsphere Composite Membranes for Guided Tissue/Bone Regeneration

Novel multifunctional chitosan-45S5 bioactive glass-poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) microsphere (CS-BG-MS) composite membranes were developed with applicability in guided tissue/bone regeneration (GTR/GBR). The incorporation of 45S5 BG and PHBV MS into CS membranes not only provided the membranes with favorable surface roughness, hydrophilicity, and flexibility but also slowed down their degradation rate. Moreover, the CS membranes became bioactive after the incorporation of 45S5 BG and capable of releasing drugs of different physicochemical properties in a controlled and sustained manner with the addition of PHBV MS. Cell culture tests showed that osteoblast-like MG-63 human osteosarcoma cells had significantly higher adhesion, cell proliferation, and alkaline phosphatase (ALP) activity on CS-BG and CS-BG-MS membranes than on neat CS membranes. Therefore, the developed bioactive CS-BG-MS membranes with potential multidrug (e.g., antibacterial and antiosteoporosis drugs) delivery capability are promising candidate membranes for GTR/GBR applications.