Bilayered construct for simultaneous regeneration of alveolar bone and periodontal ligament

Engineering periodontal tissue interfaces using multiphasic scaffolds and membranes for guided bone and tissue regeneration

Periodontal diseases are one of the greatest healthcare burdens worldwide. The periodontal tissue compartment is an anatomical tissue interface formed from the periodontal ligament, gingiva, cementum, and bone. This multifaceted composition makes tissue engineering strategies challenging to develop due to the interface of hard and soft tissues requiring multiphase scaffolds to recreate the native tissue architecture. Multilayer constructs can better mimic tissue interfaces due to the individually tuneable layers. They have different characteristics in each layer, with modulation of mechanical properties, material type, porosity, pore size, morphology, degradation properties, and drug-releasing profile all possible. The greatest challenge of multilayer constructs is to mechanically integrate consecutive layers to avoid delamination, especially when using multiple manufacturing processes. Here, we review the development of multilayer scaffolds that aim to recapitulate native periodontal tissue interfaces in terms of physical, chemical, and biological characteristics. Important properties of multiphasic biodegradable scaffolds are highlighted and summarised, with design requirements, biomaterials, and fabrication methods, as well as post-treatment and drug/growth factor incorporation discussed.

Are Local Drug Delivery Systems a Challenge in Clinical Periodontology?

Placing antimicrobial treatments directly in periodontal pockets is an example of the local administration of antimicrobial drugs to treat periodontitis. This method of therapy is advantageous since the drug concentration after application far surpasses the minimum inhibitory concentration (MIC) and lasts for a number of weeks. As a result, numerous local drug delivery systems (LDDSs) utilizing various antibiotics or antiseptics have been created. There is constant effort to develop novel formulations for the localized administration of periodontitis treatments, some of which have failed to show any efficacy while others show promise. Thus, future research should focus on the way LDDSs can be personalized in order to optimize future clinical protocols in periodontal therapy.

Recent Advances on Electrospun Nanofibers for Periodontal Regeneration

Periodontitis is an inflammatory infection caused by bacterial plaque accumulation that affects the periodontal tissues. Current treatments lack bioactive signals to induce tissue repair and coordinated regeneration of the periodontium, thus alternative strategies are needed to improve clinical outcomes. Electrospun nanofibers present high porosity and surface area and are able to mimic the natural extracellular matrix, which modulates cell attachment, migration, proliferation, and differentiation. Recently, several electrospun nanofibrous membranes have been fabricated with antibacterial, anti-inflammatory, and osteogenic properties, showing promising results for periodontal regeneration. Thus, this review aims to provide an overview of the current state of the art of these nanofibrous scaffolds in periodontal regeneration strategies. First, we describe the periodontal tissues and periodontitis, as well as the currently available treatments. Next, periodontal tissue engineering (TE) strategies, as promising alternatives to the current treatments, are addressed. Electrospinning is briefly explained, the characteristics of electrospun nanofibrous scaffolds are highlighted, and a detailed overview of electrospun nanofibers applied to periodontal TE is provided. Finally, current limitations and possible future developments of electrospun nanofibrous scaffolds for periodontitis treatment are also discussed.

Biomimetic Bilayered Scaffolds for Tissue Engineering: From Current Design Strategies to Medical Applications

Tissue damage due to cancer, congenital anomalies, and injuries needs new efficient treatments that allow tissue regeneration. In this context, tissue engineering shows a great potential to restore the native architecture and function of damaged tissues, by combining cells with specific scaffolds. Scaffolds made of natural and/or synthetic polymers and sometimes ceramics play a key role in guiding cell growth and formation of the new tissues. Monolayered scaffolds, which consist of uniform material structure, are reported as not being sufficient to mimic complex biological environment of the tissues. Osteochondral, cutaneous, vascular, and many other tissues all have multilayered structures, therefore multilayered scaffolds seem more advantageous to regenerate these tissues. In this review, recent advances in bilayered scaffolds design applied to regeneration of vascular, bone, cartilage, skin, periodontal, urinary bladder, and tracheal tissues are focused on. After a short introduction on tissue anatomy, composition and fabrication techniques of bilayered scaffolds are explained. Then, experimental results obtained in vitro and in vivo are described, and their limitations are given. Finally, difficulties in scaling up production of bilayer scaffolds and reaching the stage of clinical studies are discussed when multiple scaffold components are used.

Electrospun Nanofibers for Periodontal Treatment: A Recent Progress

Periodontitis is a major threat to oral health, prompting scientists to continuously study new treatment techniques. The nanofibrous membrane prepared via electrospinning has a large specific surface area and high porosity. On the one hand, electrospun nanofibers can improve the absorption capacity of proteins and promote the expression of specific genes. On the other hand, they can improve cell adhesion properties and prevent fibroblasts from passing through the barrier membrane. Therefore, electrospinning has unique advantages in periodontal treatment. At present, many oral nanofibrous membranes with antibacterial, anti-inflammatory, and tissue regeneration properties have been prepared for periodontal treatment. First, this paper introduces the electrospinning process. Then, the commonly used polymers of electrospun nanofibrous membranes for treating periodontitis are summarized. Finally, different types of nanofibrous membranes prepared via electrospinning for periodontal treatment are presented, and the future evolution of electrospinning to treat periodontitis is described.

The Effect of Diabetes Mellitus on IGF Axis and Stem Cell Mediated Regeneration of the Periodontium

Periodontitis and diabetes mellitus (DM) are two of the most common and challenging health problems worldwide and they affect each other mutually and adversely. Current periodontal therapies have unpredictable outcome in diabetic patients. Periodontal tissue engineering is a challenging but promising approach that aims at restoring periodontal tissues using one or all of the following: stem cells, signalling molecules and scaffolds. Mesenchymal stem cells (MSCs) and insulin-like growth factor (IGF) represent ideal examples of stem cells and signalling molecules. This review outlines the most recent updates in characterizing MSCs isolated from diabetics to fully understand why diabetics are more prone to periodontitis that theoretically reflect the impaired regenerative capabilities of their native stem cells. This characterisation is of utmost importance to enhance autologous stem cells based tissue regeneration in diabetic patients using both MSCs and members of IGF axis.

Vasoconstrictor and coagulation activator entrapped chitosan based composite hydrogel for rapid bleeding control

Chitosan (Cs) as a hemostatic agent has been in use to control hemorrage. Composite hydrogel formed by entrapment of vasoconstrictor-potassium aluminium sulfate (0.25 %PA) and coagulation activator-calcium chloride (0.25 %Ca) into Cs (2 %) hydrogel would enhance the hemostatic property of Cs. In this work, the prepared composite hydrogel was injectable, shear thinning, cyto and hemocompatible. The 2 %Cs-0.25 %PA-0.25 %Ca composite hydrogel caused rapid blood clotting by accelerating RBC/platelet aggregation and activation of the coagulation cascade. Further, in vivo studies on rat liver and femoral artery hemorrage model showed the efficiency of 2 %Cs-0.25 %PA-0.25 %Ca composite hydrogel to achieve hemostasis in a shorter time (20 ± 10 s, 105 ± 31 s) than commercial hemostatic agents-Fibrin sealant (77 ± 26 s, 204 ± 58 s) and Floseal (76 ± 15 s, 218 ± 46 s). In in vivo toxicological study, composite hydrogel showed material retention even after 8 weeks post-surgery, therefore excess hydrogel should be irrigated from site of application. This prepared composite hydrogel based hemostatic agent has potential application in low pressure bleeding sites.

Biodegradable engineered fiber scaffolds fabricated by electrospinning for periodontal tissue regeneration

Considering the specificity of periodontium and the unique advantages of electrospinning, this technology has been used to fabricate biodegradable tissue engineering materials for functional periodontal regeneration. For better biomedical quality, a continuous technological progress of electrospinning has been performed. Based on property of materials (natural, synthetic or composites) and additive novel methods (drug loading, surface modification, structure adjustment or 3 D technique), various novel membranes and scaffolds that could not only relief inflammation but also influence the biological behaviors of cells have been fabricated to achieve more effective periodontal regeneration. This review provides an overview of the usage of electrospinning materials in treatments of periodontitis, in order to get to know the existing research situation and find treatment breakthroughs of the periodontal diseases.

Nanomaterials for Periodontal Tissue Engineering: Chitosan-Based Scaffolds. A Systematic Review

Introduction. Several biomaterials are used in periodontal tissue engineering in order to obtain a three-dimensional scaffold, which could enhance the oral bone regeneration. These novel biomaterials, when placed in the affected area, activate a cascade of events, inducing regenerative cellular responses, and replacing the missing tissue. Natural and synthetic polymers can be used alone or in combination with other biomaterials, growth factors, and stem cells. Natural-based polymer chitosan is widely used in periodontal tissue engineering. It presents biodegradability, biocompatibility, and biological renewability properties. It is bacteriostatic and nontoxic and has hemostatic and mucoadhesive capacity. The aim of this systematic review is to obtain an updated overview of the utilization and effectiveness of chitosan-based scaffold (CS-bs) in the alveolar bone regeneration process. Materials and Methods. During database searching (using PubMed, Cochrane Library, and CINAHL), 72 items were found. The title, abstract, and full text of each study were carefully analyzed and only 22 articles were selected. Thirteen articles were excluded based on their title, five after reading the abstract, twenty-six after reading the full text, and six were not considered because of their publication date (prior to 2010). Quality assessment and data extraction were performed in the twelve included randomized controlled trials. Data concerning cell proliferation and viability (CPV), mineralization level (M), and alkaline phosphatase activity (ALPA) were recorded from each article Results. All the included trials tested CS-bs that were combined with other biomaterials (such as hydroxyapatite, alginate, polylactic-co-glycolic acid, polycaprolactone), growth factors (basic fibroblast growth factor, bone morphogenetic protein) and/or stem cells (periodontal ligament stem cells, human jaw bone marrow-derived mesenchymal stem cells). Values about the proliferation of cementoblasts (CB) and periodontal ligament cells (PDLCs), the activity of alkaline phosphatase, and the mineralization level determined by pure chitosan scaffolds resulted in lower than those caused by chitosan-based scaffolds combined with other molecules and biomaterials. Conclusions. A higher periodontal regenerative potential was recorded in the case of CS-based scaffolds combined with other polymeric biomaterials and bioceramics (bio compared to those provided by CS alone. Furthermore, literature demonstrated that the addition of growth factors and stem cells to CS-based scaffolds might improve the biological properties of chitosan.

Recent advances in periodontal regeneration: A biomaterial perspective

Periodontal disease (PD) is one of the most common inflammatory oral diseases, affecting approximately 47% of adults aged 30 years or older in the United States. If not treated properly, PD leads to degradation of periodontal tissues, causing tooth movement, and eventually tooth loss. Conventional clinical therapy for PD aims at eliminating infectious sources, and reducing inflammation to arrest disease progression, which cannot achieve the regeneration of lost periodontal tissues. Over the past two decades, various regenerative periodontal therapies, such as guided tissue regeneration (GTR), enamel matrix derivative, bone grafts, growth factor delivery, and the combination of cells and growth factors with matrix-based scaffolds have been developed to target the restoration of lost tooth-supporting tissues, including periodontal ligament, alveolar bone, and cementum. This review discusses recent progresses of periodontal regeneration using tissue-engineering and regenerative medicine approaches. Specifically, we focus on the advances of biomaterials and controlled drug delivery for periodontal regeneration in recent years. Special attention is given to the development of advanced bio-inspired scaffolding biomaterials and temporospatial control of multi-drug delivery for the regeneration of cementum-periodontal ligament-alveolar bone complex. Challenges and future perspectives are presented to provide inspiration for the design and development of innovative biomaterials and delivery system for new regenerative periodontal therapy.

Dental Follicle Cells: Roles in Development and Beyond

Dental follicle cells (DFCs) are a group of mesenchymal progenitor cells surrounding the tooth germ, responsible for cementum, periodontal ligament, and alveolar bone formation in tooth development. Cascades of signaling pathways and transcriptional factors in DFCs are involved in directing tooth eruption and tooth root morphogenesis. Substantial researches have been made to decipher multiple aspects of DFCs, including multilineage differentiation, senescence, and immunomodulatory ability. DFCs were proved to be multipotent progenitors with decent amplification, immunosuppressed and acquisition ability. They are able to differentiate into osteoblasts/cementoblasts, adipocytes, neuron-like cells, and so forth. The excellent properties of DFCs facilitated clinical application, as exemplified by bone tissue engineering, tooth root regeneration, and periodontium regeneration. Except for the oral and maxillofacial regeneration, DFCs were also expected to be applied in other tissues such as spinal cord defects (SCD), cardiomyocyte destruction. This article reviewed roles of DFCs in tooth development, their properties, and clinical application potentials, thus providing a novel guidance for tissue engineering.

Advance of Nano-Composite Electrospun Fibers in Periodontal Regeneration

Periodontitis is considered to be the main cause of tooth loss, which affects about 15% of the adult population around the world. Scaling and root-planning are the conventional treatments utilized to remove the contaminated tissue and bacteria, but eventually lead to the formation of a poor connection—long junctional epithelium. Therefore, regenerative therapies, such as guided tissue/bone regeneration (GTR/GBR) for periodontal regeneration have been attempted. GTR membranes, acting as scaffolds, create three-dimensional (3D) environment for the guiding of cell attachment, proliferation and differentiation, and play a significant role in periodontal regeneration. Nano-composite scaffolds based on electrospun nanofibers have gained great attention due to their ability to emulate natural extracellular matrix (ECM) that affects cell survival, attachment and reorganization. Promoted protein absorption, cellular reactions, activation of specific gene expression and intracellular signaling, and high surface area to volume ratio are also important properties of nanofibrous scaffolds. Moreover, several bioactive components, such as bioceramics and functional polymers can be easily blended into nanofibrous matrixes to regulate the physical-chemical-biological properties and regeneration abilities. Simultaneously, functional growth factors, proteins and drugs are also incorporated to regulate cellular reactions and even modify the local inflammatory microenvironment, which benefit periodontal regeneration and functional restoration. Herein, the progress of nano-composite electrospun fibers for periodontal regeneration is reviewed, including fabrication methods, compound types and processes, and surface modifications, etc. Significant proof-of-concept examples are utilized to illustrate the results of material characteristics, cellular interactions and periodontal regenerations. Finally, the existing limitations of nano-composite electrospun fibers and the development tendencies in future are also discussed.

Chitosan hydrogel scaffold reinforced with twisted poly(l lactic acid) aligned microfibrous bundle to mimic tendon extracellular matrix

Regeneration of tendon requires construct that provides necessary structural support closely mimicking the native architecture. To recreate this complex architecture a construct made of heat-treated, twisted poly(L lactic acid) (PLLA) microfibers coated with chitosan gel and surrounded by PLLA micro-fibrous layer was developed. The developed construct characterized using SEM showed the macroporous nature of gel coating around four distinct PLLA twisted fibrous bundle and a thin fiber layer surrounding the construct. FTIR analysis confirmed the presence of PLLA and chitosan construct. Mechanical strength increased with increasing number of strips. Protein adsorption was significantly low on the construct with outer covering that could retard cell adhesion to the outer layer. The developed construct showed good cell attachment and proliferation of tenocytes. These results indicate that the construct would find application for tendon tissue engineering.

Advanced smart biomaterials and constructs for hard tissue engineering and regeneration

Hard tissue repair and regeneration cost hundreds of billions of dollars annually worldwide, and the need has substantially increased as the population has aged. Hard tissues include bone and tooth structures that contain calcium phosphate minerals. Smart biomaterial-based tissue engineering and regenerative medicine methods have the exciting potential to meet this urgent need. Smart biomaterials and constructs refer to biomaterials and constructs that possess instructive/inductive or triggering/stimulating effects on cells and tissues by engineering the material's responsiveness to internal or external stimuli or have intelligently tailored properties and functions that can promote tissue repair and regeneration. The smart material-based approaches include smart scaffolds and stem cell constructs for bone tissue engineering; smart drug delivery systems to enhance bone regeneration; smart dental resins that respond to pH to protect tooth structures; smart pH-sensitive dental materials to selectively inhibit acid-producing bacteria; smart polymers to modulate biofilm species away from a pathogenic composition and shift towards a healthy composition; and smart materials to suppress biofilms and avoid drug resistance. These smart biomaterials can not only deliver and guide stem cells to improve tissue regeneration and deliver drugs and bioactive agents with spatially and temporarily controlled releases but can also modulate/suppress biofilms and combat infections in wound sites. The new generation of smart biomaterials provides exciting potential and is a promising opportunity to substantially enhance hard tissue engineering and regenerative medicine efficacy.

Trends in polymeric electrospun fibers and their use as oral biomaterials

Electrospinning is one of the techniques to produce structured polymeric fibers in the micro or nano scale and to generate novel materials for biomedical proposes. Electrospinning versatility provides fibers that could support different surgical and rehabilitation treatments. However, its diversity in equipment assembly, polymeric materials, and functional molecules to be incorporated in fibers result in profusion of recent biomaterials that are not fully explored, even though the recognized relevance of the technique. The present article describes the main electrospun polymeric materials used in oral applications, and the main aspects and parameters of the technique. Natural and synthetic polymers, blends, and composites were identified from the available literature and recent developments. Main applications of electrospun fibers were focused on drug delivery systems, tissue regeneration, and material reinforcement or modification, although studies require further investigation in order to enable direct use in human. Current and potential usages as biomaterials for oral applications must motivate the development in the use of electrospinning as an efficient method to produce highly innovative biomaterials, over the next few years. Impact statement Nanotechnology is a challenge for many researchers that look for obtaining different materials behaviors by modifying characteristics at a very low scale. Thus, the production of nanostructured materials represents a very important field in bioengineering, in which the electrospinning technique appears as a suitable alternative. This review discusses and provides further explanation on this versatile technique to produce novel polymeric biomaterials for oral applications. The use of electrospun fibers is incipient in oral areas, mainly because of the unfamiliarity with the technique. Provided disclosure, possibilities and state of the art are aimed at supporting interested researchers to better choose proper materials, understand, and design new experiments. This work seeks to encourage many other researchers-Dentists, Biologists, Engineers, Pharmacists-to develop innovative materials from different polymers. We highlight synthetic and natural polymers as trends in treatments to motivate an advance in the worldwide discussion and exploration of this interdisciplinary field.

Bioactive Sr(II)/Chitosan/Poly(ε-caprolactone) Scaffolds for Craniofacial Tissue Regeneration. In Vitro and In Vivo Behavior

In craniofacial tissue regeneration, the current gold standard treatment is autologous bone grafting, however, it presents some disadvantages. Although new alternatives have emerged there is still an urgent demand of biodegradable scaffolds to act as extracellular matrix in the regeneration process. A potentially useful element in bone regeneration is strontium. It is known to promote stimulation of osteoblasts while inhibiting osteoclasts resorption, leading to neoformed bone. The present paper reports the preparation and characterization of strontium (Sr) containing hybrid scaffolds formed by a matrix of ionically cross-linked chitosan and microparticles of poly(ε-caprolactone) (PCL). These scaffolds of relatively facile fabrication were seeded with osteoblast-like cells (MG-63) and human bone marrow mesenchymal stem cells (hBMSCs) for application in craniofacial tissue regeneration. Membrane scaffolds were prepared using chitosan:PCL ratios of 1:2 and 1:1 and 5 wt % Sr salts. Characterization was performed addressing physico-chemical properties, swelling behavior, in vitro biological performance and in vivo biocompatibility. Overall, the composition, microstructure and swelling degree (≈245%) of scaffolds combine with the adequate dimensional stability, lack of toxicity, osteogenic activity in MG-63 cells and hBMSCs, along with the in vivo biocompatibility in rats allow considering this system as a promising biomaterial for the treatment of craniofacial tissue regeneration.

Periodontal ligament‑associated protein‑1 delays rat periodontal bone defect repair by regulating osteogenic differentiation of bone marrow stromal cells and osteoclast activation

The aim of the present study was to assess the roles of periodontal ligament‑associated protein‑1 (PLAP‑1) in the osteogenic differentiation of rat bone marrow stromal cells (rBMSCs) and in osteoclast activation during the repair of rat periodontal bone defects. Male, 6‑week‑old, Wistar rats treated with periodontal bone defects were randomly assigned to 3 groups: The PLAP‑1‑transfected rBMSC group (PLAP‑1 group), the empty vector‑transfected rBMSC group (vector group) and the normal rBMSC group (control group). Specimens were obtained at 2, 4 and 6 weeks post‑surgery. Histological observation and micro‑computed tomography were applied to evaluate the repair effect. The bone defect areas of the mandible were dissected for western blotting and reverse transcription-quantitative polymerase chain reaction (RT‑qPCR). Osteogenesis‑associated proteins, including alkaline phosphatase (ALP), bone sialoprotein (BSP), runt-related transcription factor 2 (Runx2), Osterix (Osx) and osteocalcin (OC), as indicators of rBMSC‑induced osteogenesis, were examined by RT-qPCR and western blotting. Osteoclasts were identified and quantified using tartrate‑resistant acid phosphatase staining. Meanwhile, the receptor activator of nuclear factor κΒ ligand (RANKL)/οsteoprotegerin (OPG) ratio was quantified to assess osteoclast activation by western blotting. Τhe repair effect of the PLAP‑1 group was significantly worse than that of the vector and control groups. In the PLAP‑1 group, newly formed and mineralized bones were significantly less in quantity than that in the other two groups (P<0.05), and the expression of osteogenic proteins (ALP, BSP, Runx2, Osx and OC) was also reduced (P<0.01). However, there was no significant difference between the vector and control groups. The RANKL/OPG ratio was upregulated in the PLAP‑1 group due to decreased OPG protein expression and a simultaneous increase in RANKL protein expression (P<0.01), and more osteoclasts were activated in the PLAP‑1 group (P<0.01). In conclusion, the present study found that PLAP‑1 delays rat periodontal bone defect repair by inhibiting osteogenic differentiation and promoting osteoclast activation, mainly dependent on the upregulation of the RANKL/OPG ratio.

Engineered scaffolds and cell-based therapy for periodontal regeneration

BACKGROUND

The main objective of regenerative periodontal therapy is to completely restore the periodontal tissues lost. This review summarizes the most recent evidence in support of scaffold- and cell-based tissue engineering, which are expected to play a relevant role in next-generation periodontal regenerative therapy.

METHODS

A literature search (PubMed database) was performed to analyze more recently updated articles regarding periodontal regeneration, scaffolds and cell-based technologies.

RESULTS

Evidence supports the importance of scaffold physical cues to promote periodontal regeneration, including scaffold multicompartmentalization and micropatterning. The in situ delivery of biological mediators and/or cell populations, both stem cells and already differentiated cells, has shown promising in vivo efficacy.

CONCLUSIONS

Porous scaffolds are pivotal for clot stabilization, wound compartmentalization, cell homing and cell nutrients delivery. Given the revolutionary introduction of rapid prototyping technique and cell-based therapies, the fabrication of custom-made scaffolds is not far from being achieved.

Chitosan-Based Trilayer Scaffold for Multitissue Periodontal Regeneration

Periodontal regeneration is still a challenge for periodontists and tissue engineers, as it requires the simultaneous restoration of different tissues-namely, cementum, gingiva, bone, and periodontal ligament (PDL). Here, we synthetized a chitosan (CH)-based trilayer porous scaffold to achieve periodontal regeneration driven by multitissue simultaneous healing. We produced 2 porous compartments for bone and gingiva regeneration by cross-linking with genipin either medium molecular weight (MMW) or low molecular weight (LMW) CH and freeze-drying the resulting scaffolds. We synthetized a third compartment for PDL regeneration by CH electrochemical deposition; this allowed us to produce highly oriented microchannels of about 450-µm diameter intended to drive PDL fiber growth toward the dental root. In vitro characterization showed rapid equilibrium water content for MMW-CH and LMW-CH compartments (equilibrium water content after 5 min >85%). The MMW-CH compartment degraded more slowly and provided significantly more resistance to compression (28% ± 1% of weight loss at 4 wk; compression modulus H_A = 18 ± 6 kPa) than the LMW-CH compartment (34% ± 1%; 7.7 ± 0.8 kPa) as required to match the physiologic healing rates of bone and gingiva and their mechanical properties. More than 90% of all human primary periodontal cell populations tested on the corresponding compartment survived during cytocompatibility tests, showing active cell metabolism in the alkaline phosphatase and collagen deposition assays. In vivo tests showed high biocompatibility in wild-type mice, tissue ingrowth, and vascularization within the scaffold. Using the periodontal ectopic model in nude mice, we preseeded scaffold compartments with human gingival fibroblasts, osteoblasts, and PDL fibroblasts and found a dense mineralized matrix within the MMW-CH region, with weakly mineralized deposits at the dentin interface. Together, these results support this resorbable trilayer scaffold as a promising candidate for periodontal regeneration.

Tri-Layered Nanocomposite Hydrogel Scaffold for the Concurrent Regeneration of Cementum, Periodontal Ligament, and Alveolar Bone

A tri-layered scaffolding approach is adopted for the complete and concurrent regeneration of hard tissues-cementum and alveolar bone-and soft tissue-the periodontal ligament (PDL)-at a periodontal defect site. The porous tri-layered nanocomposite hydrogel scaffold is composed of chitin-poly(lactic-co-glycolic acid) (PLGA)/nanobioactive glass ceramic (nBGC)/cementum protein 1 as the cementum layer, chitin-PLGA/fibroblast growth factor 2 as the PDL layer, and chitin-PLGA/nBGC/platelet-rich plasma derived growth factors as the alveolar bone layer. The tri-layered nanocomposite hydrogel scaffold is cytocompatible and favored cementogenic, fibrogenic, and osteogenic differentiation of human dental follicle stem cells. In vivo, tri-layered nanocomposite hydrogel scaffold with/without growth factors is implanted into rabbit maxillary periodontal defects and compared with the controls at 1 and 3 months postoperatively. The tri-layered nanocomposite hydrogel scaffold with growth factors demonstrates complete defect closure and healing with new cancellous-like tissue formation on microcomputed tomography analysis. Histological and immunohistochemical analyses further confirm the formation of new cementum, fibrous PDL, and alveolar bone with well-defined bony trabeculae in comparison to the other three groups. In conclusion, the tri-layered nanocomposite hydrogel scaffold with growth factors can serve as an alternative regenerative approach to achieve simultaneous and complete periodontal regeneration.

Bioactive Polymeric Nanoparticles for Periodontal Therapy

Aims

to design calcium and zinc-loaded bioactive and cytocompatible nanoparticles for the treatment of periodontal disease.

Methods

PolymP-nActive nanoparticles were zinc or calcium loaded. Biomimetic calcium phosphate precipitation on polymeric particles was assessed after 7 days immersion in simulated body fluid, by scanning electron microscopy attached to an energy dispersive analysis system. Amorphous mineral deposition was probed by X-ray diffraction. Cell viability analysis was performed using oral mucosa fibroblasts by: 1) quantifying the liberated deoxyribonucleic acid from dead cells, 2) detecting the amount of lactate dehydrogenase enzyme released by cells with damaged membranes, and 3) by examining the cytoplasmic esterase function and cell membranes integrity with a fluorescence-based method using the Live/Dead commercial kit. Data were analyzed by Kruskal-Wallis and Mann-Whitney tests.

Results

Precipitation of calcium and phosphate on the nanoparticles surfaces was observed in calcium-loaded nanoparticles. Non-loaded nanoparticles were found to be non-toxic in all the assays, calcium and zinc-loaded particles presented a dose dependent but very low cytotoxic effect.

Conclusions

The ability of calcium-loaded nanoparticles to promote precipitation of calcium phosphate deposits, together with their observed non-toxicity may offer new strategies for periodontal disease treatment.

Layered chitosan-collagen hydrogel/aligned PLLA nanofiber construct for flexor tendon regeneration

The aim of our study was to develop a tendon construct of electrospun aligned poly (l-lactic acid) (PLLA) nanofibers, to mimic the aligned collagen fiber bundles and layering PLLA fibers with chitosan-collagen hydrogel, to mimic the glycosaminoglycans of sheath ECM for tendon regeneration. The hydrogel coated electrospun membrane was rolled and an outer coating of alginate gel was given to prevent peritendinous adhesion. The developed constructs were characterized by SEM, FT-IR and tensile testing. Protein adsorption studies showed lower protein adsorption on coated scaffolds compared to uncoated scaffolds. The samples were proven to be non-toxic to tenocytes. The chitosan-collagen/PLLA uncoated scaffolds and alginate gel coated chitosan-collagen/PLLA scaffolds showed good cell proliferation. The tenocytes showed good attachment and spreading on the scaffolds. This study indicated that the developed chitosan-collagen/PLLA/alginate scaffold would be suitable for flexor tendon regeneration.

Potential of Electrospun Nanofibers for Biomedical and Dental Applications

Electrospinning is a versatile technique that has gained popularity for various biomedical applications in recent years. Electrospinning is being used for fabricating nanofibers for various biomedical and dental applications such as tooth regeneration, wound healing and prevention of dental caries. Electrospun materials have the benefits of unique properties for instance, high surface area to volume ratio, enhanced cellular interactions, protein absorption to facilitate binding sites for cell receptors. Extensive research has been conducted to explore the potential of electrospun nanofibers for repair and regeneration of various dental and oral tissues including dental pulp, dentin, periodontal tissues, oral mucosa and skeletal tissues. However, there are a few limitations of electrospinning hindering the progress of these materials to practical or clinical applications. In terms of biomaterials aspects, the better understanding of controlled fabrication, properties and functioning of electrospun materials is required to overcome the limitations. More in vivo studies are definitely required to evaluate the biocompatibility of electrospun scaffolds. Furthermore, mechanical properties of such scaffolds should be enhanced so that they resist mechanical stresses during tissue regeneration applications. The objective of this article is to review the current progress of electrospun nanofibers for biomedical and dental applications. In addition, various aspects of electrospun materials in relation to potential dental applications have been discussed.