A Novel Approach for the Treatment of Recurrent Oroantral Fistula Occurring at an Infected Sinus Augmentation Site.

Closing a recurrent oroantral fistula (OAF) that occurs at an infected sinus augmentation site is a challenge for clinicians. The recurrent OAF has a detrimental impact on bone regeneration and subsequent implant placement. This case report includes three cases in which sinus graft infection and OAF occurred after maxillary sinus augmentation (MSA). In these cases, treatments to control sinus infection were performed using an otolaryngologist; then, intraoral interventions comprising mucosal flap procedures, bone grafts, and barrier membrane applications were performed 2-5 times by oral surgeons. Nevertheless, OAF recurred persistently. The failure to stop OAF recurrence may be due to the inability to effectively block air pressure at the OAF site. Following a comprehensive debridement of the infected tissue at the previous sinus augmentation site, a pouch was created through sinus mucosal elevation. The perforated sinus mucosa at the OAF site was covered with a non-resorbable membrane in one case and with resorbable collagen membranes in the other two cases, followed by bone grafting within the pouch. Lastly, this procedure was completed by blocking the entrance of the pouch with a cortical bone shell graft and a resorbable collagen membrane. The cortical bone shell graft, obstructing the air pressure from the nasal cavity, facilitated bone formation, and, ultimately, allowed for implant placement. Within the limitations of the present case report, the application of a guided bone regeneration technique involving a cortical bone shell graft and a barrier membrane enabled the closure of the recurrent OAF and subsequent implant placement.

Digital Workflow for Retrofitting a Surveyed Crown Using a Removable Partial Denture as an Antagonist.

Digital workflow expedites the procedure of retrofitting a surveyed crown against an existing removable partial denture (RPD). This article describes a simple and straightforward technique of digital workflow where an existing RPD is scanned as an antagonist to design the rest seat, guide plane, and height of contour of a surveyed crown.

The use of heparin chemistry to improve dental osteogenesis associated with implants.

In this study, we designed a hybrid Ti by heparin modifying the Ti surface followed by Growth/differentiation factor-5 (GDF-5) loading. After that, products were characterized by physicochemical analysis. Quantitative analysis of functionalized groups was also confirmed. The release behavior of GDF-5 grafted samples was confirmed for up to 21days. The surface modification process was found to be successful and to effectively immobilize GDF-5 and provide for its sustained release behavior. As an in vitro test, GDF-5 loaded Ti showed significantly enhanced osteogenic differentiation with increased calcium deposition under nontoxic conditions against periodontal ligament stem cells (PDLSc). Furthermore, an in vivo result showed that GDF-5 loaded Ti had a significant influence on new bone formation in a rabbit model. These results clearly confirmed that our strategy may suggest a useful paradigm by inducing osseo-integration as a means to remodeling and healing of bone defects for restorative procedures in dentistry.

Poly(l-Lactic Acid)/Gelatin Fibrous Scaffold Loaded with Simvastatin/Beta-Cyclodextrin-Modified Hydroxyapatite Inclusion Complex for Bone Tissue Regeneration.

Recently, the application of nanostructured materials in the field of tissue engineering has garnered attention to mediate treatment and regeneration of bone defects. In this study, poly(l-lactic acid) (PLLA)/gelatin (PG) fibrous scaffolds are fabricated and ß-cyclodextrin (ßCD) grafted nano-hydroxyapatite (HAp) is coated onto the fibrous scaffold surface via an interaction between ßCD and adamantane. Simvastatin (SIM), which is known to promote osteoblast viability and differentiation, is loaded into the remaining ßCD. The specimen morphologies are characterized by scanning electron microscopy. The release profile of SIM from the drug loaded scaffold is also evaluated. In vitro proliferation and osteogenic differentiation of human adipose derived stem cells on SIM/HAp coated PG composite scaffolds is characterized by alkaline phosphatase (ALP) activity, mineralization (Alizarin Red S staining), and real time Polymerase chain reaction (PCR). The scaffolds are then implanted into rabbit calvarial defects and analyzed by microcomputed tomography for bone formation after four and eight weeks. These results demonstrate that SIM loaded PLLA/gelatin/HAp-(ßCD) scaffolds promote significantly higher ALP activity, mineralization, osteogenic gene expression, and bone regeneration than control scaffolds. This suggests the potential application of this material toward bone tissue engineering.

Development of Poly(ɛ-caprolactone) Scaffold Loaded with Simvastatin and Beta-Cyclodextrin Modified Hydroxyapatite Inclusion Complex for Bone Tissue Engineering.

In this study, we developed poly(ɛ-caprolactone) (PCL) 3D scaffolds using a solid free form fabrication (SFF) technique. ß-cyclodextrin (ßCD) was grafted to hydroxyapatite (HAp) and this ßCD grafted HAp was coated onto the PCL scaffold surface, followed by drug loading through an inclusion complex interaction between the ßCD and adamantane (AD) or between ßCD and simvastatin (SIM). The scaffold structure was characterized by scanning electron microscopy (SEM). The release profile of simvastatin in the ß-CD grafted HAp was also evaluated. Osteogenic differentiation of adipose-derived stromal cells (ADSCs) was examined using an alkaline phosphatase activity (ALP) assay. The results suggest that drug loaded PCL-HAp 3-D scaffolds enhances osteogenic differentiation of ADSCs.

Current progress in nanotechnology applications for diagnosis and treatment of kidney diseases.

Significant progress has been made in nanomedicine, primarily in the form of nanoparticles, for theranostic applications to various diseases. A variety of materials, both organic and inorganic, have been used to develop nanoparticles with promise to achieve improved efficacy in medical applications as well as reduced systemic side effects compared to current standard of care medical practices. In particular, this article highlights the recent development and application of nanoparticles for diagnosing and treating nephropathologies.

The effect of gold nanoparticle size on osteogenic differentiation of adipose-derived stem cells.

There have been many medical applications based on gold nanoparticles (GNPs) over the past several centuries. Recently, researchers have focused on bone tissue engineering applications utilizing GNPs. The effect of various sizes of gold nanoparticles on the differentiation of human adipose-derived stem cells (ADSCs) into osteoblasts was investigated. The concentration of gold nanoparticles was fixed at 1 µM and varying sizes of 15, 30, 50, 75 and 100 nm (spherical GNPs) were used. The lack of cytotoxicity was confirmed by establishing viability of ADSCs using cell counting kit-8 (CCK-8) and live/dead assays. The results showed that each size of GNPs had no significant toxicity on ADSCs during 1 week of incubation. Osteogenic differentiation of ADSCs was confirmed by alkaline phosphatase (ALP) staining, ALP activity, calcium deposition, and real time PCR experiments. It was found, through dark field assays and microscope cell images, that 30 nm and 50 nm GNPs were preferentially up taken into the ADSCs. As expected, all sizes of gold nanoparticles promoted the differentiation of ADSCs toward osteoblasts more than control. Among all sizes, 30 and 50 nm GNPs appeared to have the highest differentiation rates. The data consistently demonstrated that 30 and 50 nm GNPs are the most effective in promoting osteogenic differentiation of ADSCs.

Inhibition of osteoclast differentiation by gold nanoparticles functionalized with cyclodextrin curcumin complexes.

Gold nanoparticles (GNPs) have been previously reported to inhibit osteoclast (OC) formation. However, previous research only confirmed the osteoclastogenesis inhibitory effect under in vitro conditions. The aim of this study was to develop a therapeutic agent for osteoporosis based on the utilization of GNPs and confirm their effect both in vitro and in vivo. We prepared ß-cyclodextrin (CD) conjugated GNPs (CGNPs), which can form inclusion complexes with curcumin (CUR-CGNPs), and used these to investigate their inhibitory effects on receptor activator of nuclear factor-κb ligand (RANKL)-induced osteoclastogenesis in bone marrow-derived macrophages (BMMs). The CUR-CGNPs significantly inhibited the formation of tartrate-resistant acid phosphatase (TRAP)-positive multinuclear cells in BMMs without inducing cytotoxicity. The mRNA expressions of genetic markers of OC differentiation including c-Fos, nuclear factor of activated T cells 1 (NFATc1), TRAP, and osteoclast associated receptor (OSCAR) were significantly decreased in the presence of CUR-CGNPs. In addition, the CUR-CGNPs inhibited OC differentiation of BMMs through suppression of the RANKL-induced signaling pathway. Additionally, CUR-CGNPs caused a decrease in RANKL-induced actin ring formation, which is an essential morphological characteristic of OC formation allowing them to carry out bone resorption activity. Furthermore, the in vivo results of an ovariectomy (OVX)-induced osteoporosis model showed that CUR-CGNPs significantly improved bone density and prevented bone loss. Therefore, CUR-CGNPs may prove to be useful as therapeutic agents for preventing and treating osteoporosis.

Electrospun chitosan nanofibers with controlled levels of silver nanoparticles. Preparation, characterization and antibacterial activity.

The ideal wound dressing would have properties that allow for absorption of exudates, and inhibition of microorganism for wound protection. In this study, we utilized an electrospinning (ELSP) technique to design a novel wound dressing. Chitosan (CTS) nanofibers containing various ratios of silver nanoparticles (AgNPs) were obtained. AgNPs were generated directly in the CTS solution by using a chemical reduction method. The formation and presence of AgNPs in the CTS/AgNPs composite was confirmed by x-ray diffraction (XRD), ultraviolet-visible spectroscopy (UV) and thermogravimetric analysis (TGA). The electrospun CTS/AgNPs nanofibers were characterized morphologically by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). These nanofibers were subsequently tested to evaluate their antibacterial activity against gram-negative Pseudomonas aeruginosa (P. aeruginosa) and gram-positive Methicillin-resistant Staphylococcus aureus (MRSA). Results of this antibacterial testing suggest that CTS/AgNPs nanofibers may be effective in topical antibacterial treatment in wound care.

Photo-cured hyaluronic acid-based hydrogels containing growth and differentiation factor 5 (GDF-5) for bone tissue regeneration.

In this study we describe the generation and influences on in vitro and in vivo osteogenesis of photo-cured hyaluronic acid (HA) hydrogels loaded with growth and differentiation factor 5 (GDF-5). Prior to loading GDF-5, we characterized the release profiles from these hydrogels and tested their respective cell viability, differentiation and in vivo bone regeneration. The results from this testing indicated that GDF-5 was observed to release in a sustained manner from the HA hydrogels I-III. MTT and Live/Dead assays showed that the HA hydrogels I-III have good biocompatibility for use as scaffolds for bone tissue regeneration. In vitro cell tests showed a higher level of MC3T3-E1 cell proliferation and differentiation on HA hydrogels I-III than on HA hydrogel 0. Moreover, in vivo animal tests showed that the HA hydrogels I and III had a significant improvement on osteogenesis. Overall, our results suggest that the HA-based hydrogel is a good biomaterial to deliver osteogenic differentiation factors such as GDF-5, and GDF-5 can be useful as an effective alternative to aid new bone formation.

Enhanced bone regeneration with a gold nanoparticle-hydrogel complex.

Gold nanoparticles (GNPs) are widely used in diagnostics, drug delivery, biomedical imaging, and photo-thermal therapy due to their surface plasmon resonance, fluorescence, and easy-surface functionalization. According to recent studies, GNPs display a positive effect on the osteogenic differentiation of mesenchymal stem cells (MSCs) and MC3T3-E1 osteoblast-like cells. The aim of this study was to develop a new approach for bone tissue regeneration based on the utilization of a biodegradable hydrogel loaded with GNPs. We have used photo-curable gelatin hydrogels (Gel) in order to provide a proof of principle of GNPs in regeneration strategies for bone tissue repair. We have investigated the effects of these Gel-GNP composite hydrogels both in vitro and in vivo. The in vitro results showed that the hydrogels loaded with GNPs promote proliferation, differentiation, and alkaline phosphate (ALP) activities of human adipose-derived stem cells (ADSCs) as they differentiate towards osteoblast cells in a dose-dependent manner. Moreover, the in vivo results showed that these hydrogels loaded with high concentrations of GNPs had a significant influence on new bone formation. Through these in vitro and vivo tests, we found that the Gel-GNP can be a useful material for bone tissue engineering.

Chitosan/polyurethane blended fiber sheets containing silver sulfadiazine for use as an antimicrobial wound dressing.

Electrospun chitosan (CTS) nanofibers have been well known for use as a wound dressing in the biomedical field. Nevertheless, fatal bacterial infections are still a serious problem when CTS nanofibers are used for wound treatment. In this study, we designed a novel wound dressing based on blending the chitosan with polyurethane (CTS/PU) containing silver sulfadiazine (AgSD) in order to enhance both antibacterial activity and mechanical strength. This fiber sheet was produced using the electrospinning (ELSP) technique. The CTS/PU containing AgSD fiber sheet was characterized by energy-dispersive X-ray spectroscopy (EDX). The physicochemical properties of the CTS/PU/AgSD fiber sheets were also characterized by thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FT-IR). The electrospun fibers were morphologically characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). For an in vitro evaluation, the CTS/PU/AgSD fiber sheets were tested for their antibacterial activity against gram-negative Pseudomonas aeruginosa (P. aeruginosa), gram-positive Staphylococcus aureus (S. aureus) and Methicillin-resistant Staphylococcus aureus (MRSA). The results indicate that CTS/PU/AgSD fiber sheets have strong antimicrobial activity as displayed by inhibition of bacterial growth and prevention of infection during the healing process. These results indicate that this material would be good for use as a wound dressing material.

Poly(L-lactic acid)/hydroxyapatite nanocylinders as nanofibrous structure for bone tissue engineering scaffolds.

Poly (L-lactic acid) (PLLA), a biodegradable and biocompatible polyester, has been used as material of for tissue engineered scaffold and regenerative medicine. In this study, hydroxyapatite (HAp) and PLLA composite was electrospun. PLLA fibers were treated with an amino groups containing base in order to fabricate amino groups modified polymeric microcylinders. Simvastatin was loaded into the PLLA/HAp microcylinders. Our study focuses on the incorporation HAp and Simvastatin into the fibrous and cylindrical structure, its effects on the loading and release of simvastatin, and biological responses to osteoblast cells. The aspect ratio of microcylinders was tunable by varying the aminolysis treatment time and density of the base. The effects of the PLLA/HAp composites on osteoblast cell proliferation were evaluated. The PLLA/HAp may interact with osteoblast and obtain desired effects that were stimulating osteoblast function and restraining the osteoclast function for bone tissue regeneration. The potential of the developed composite microcylinders could be a promising way to fabricate the microfibrous structural scaffold that accelerates cell proliferation and functions for bone tissue engineering.

Burn-wound healing effect of gelatin/polyurethane nanofiber scaffold containing silver-sulfadiazine.

Despite the fact that advances of burn treatment have led to reduction in the morbidity caused by burns, burn infection is still a serious problem. In this study, we designed blended synthetic and natural polymers nanofiber scaffolds using polyurethane (PU) and gelatin, which were prepared by an electrospinning method. Silver-sulfadiazine (SSD) was co-mixed to the blended polymer solution for being incorporated into the nanofibers after the electrospinning, followed by examination of burn-wound healing effect. The nanofiber scaffolds containing SSD should not only serve as a substrate for skin regeneration, but may also deliver suitable drugs, within a controlled manner during healing. The SSD release was able to prevent the growth of a wide array of bacteria and accelerate the wound healing by preventing infection. Therefore it could accelerate the burn-wound closure rate. We confirmed that PU/gelatin nanofiber scaffolds containing SSD lead to enhanced regeneration of burn-wounds.

ZrO2 surface chemically coated with hyaluronic acid hydrogel loading GDF-5 for osteogenesis in dentistry.

The objective of this study was to modify zirconium dioxide (ZrO(2)) with photo-cured hyaluronic acid hydrogel (pcHAgel), and to subsequently evaluate the bone regeneration potential of the modified ZrO(2). In the present study, HA grafted onto a ZrO(2) substrate was investigated for its biocompatibility and other properties. We describe the positive influences of ZrO(2) surface-modified with pcHAgel (Zr-3) containing two different loads of growth and differentiation factor-5 (GDF-5) to aid new bone formation as compared to the same amount of BMP-2 (Zr-4-7). We characterized the Zr-3 for their surface morphology and chemical properties. Atomic force microscopy (AFM), scanning electron microscope (SEM), and X-ray photoelectron spectroscopy (XPS) showed that the pcHAgel was successfully grafted onto the ZrO(2) surface. The sustained release of GDF-5 and BMP-2 were observed to occur in the Zr-4-7. In vitro cell tests showed a higher level of MG63 cell proliferation and differentiation on Zr-4-7 than on Zr-3. The Zr-3 is a good biomaterial to deliver osteogenic differentiation factors such as BMP-2 and GDF-5, and GDF-5 can be useful as an effective alternative to aid new bone formation as compared to BMP-2.

Gold nanoparticles surface-functionalized with paclitaxel drug and biotin receptor as theranostic agents for cancer therapy.

We describe in this study whether the gold nanoparticle (AuNP) surface-functionalized with PEG, biotin, paclitaxel (PTX) and rhodamine B linked beta-cyclodextrin (ß-CD) (AuNP-5') can be useful as a theranostic agent for cancer therapy without the cytotoxic effect on normal cells. Prior to surface-functionalizing AuNPs, the cytotoxicity of the nanoparticles was evaluated, followed by their cytocompatibility. PTX, an anti-cancer agent, formed inclusion complexations with ß-CD conjugated AuNPs, and effectively released from the AuNP-2' surface-functionalized with PEG, beta-cyclodextrin (ß-CD) and paclitaxel (PTX) using the intracellular glutathione (GSH) level (10 mm). Two types of AuNP-4 surface-functionalized with PEG and rhodamine B linked ß-CD and AuNP-5 surface-functionalized PEG, biotin and rhodamine B linked ß-CD were used for evaluating their specific interaction on cancer cells such as HeLa, A549 and MG63. These were also tested against normal NIH3T3 cell, determining that the AuNP-5 was more effectively involved with the cancer cells. Confocal laser scanning microscopy (CLSM), fluorescence-activated cell-sorting (FACS) and cell viability analyses showed that the AuNP-5' plays a significant role in the diagnosis and therapy of the cancer cells, and may be used in theranostic agents.

Effect of heparin and alendronate coating on titanium surfaces on inhibition of osteoclast and enhancement of osteoblast function.

The failure of orthopedic and dental implants has been attributed mainly to loosening of the implant from host bone, which may be due to weak bonding of the implant material to bone tissue. Titanium (Ti) is used in the field of orthopedic and dental implants because of its excellent biocompatibility and outstanding mechanical properties. Therefore, in the field of materials science and tissue engineering, there has been extensive research to immobilize bioactive molecules on the surface of implant materials in order to provide the implants with improved adhesion to the host bone tissue. In this study, chemically active functional groups were introduced on the surface of Ti by a grafting reaction with heparin and then the Ti was functionalized by immobilizing alendronate onto the heparin-grafted surface. In the MC3T3-E1 cell osteogenic differentiation study, the alendronate-immobilized Ti substrates significantly enhanced alkaline phosphatase activity (ALP) and calcium content. Additionally, nuclear factor kappa B ligand (RANKL)-induced osteoclast differentiation of RAW264.7 cells was inhibited with the alendronate-immobilized Ti as confirmed by TRAP analysis. Real time PCR analysis showed that mRNA expressions of osteocalcin and osteopontin, which are markers for osteogenesis, were upregulated in MC3T3-E1 cells cultured on alendronate-immobilized Ti. The mRNA expressions of TRAP and Cathepsin K, markers for osteoclastogenesis, in RAW264.7 cells cultured on alendronate-immobilized Ti were down-regulated. Our study suggests that alendronate-immobilized Ti may be a bioactive implant with dual functions to enhance osteoblast differentiation and to inhibit osteoclast differentiation simultaneously.

Photo-cured hyaluronic acid-based hydrogels containing simvastatin as a bone tissue regeneration scaffold.

We describe in this study the positive influences on in vitro and in vivo osteogenesis of photo-cured hyaluronic acid (HA) hydrogels loaded with simvastatin (SIM). Prior to loading SIM, we first characterized the HA hydrogels for their mechanical properties and swelling ratios. The results from this testing indicated that these two factors improved as the substitution degree of 2-aminoethyl methacrylate (AEMA) increased. MTT and live/dead assays showed that the HA hydrogels have good biocompatibility for use as scaffolds for bone tissue regeneration. Moreover, another MTT assay showed that the photo-cured HA hydrogels III fabricated with 30% AEMA (300 mg) conjugated HA (HA-AEMA iii) loaded with between 0.1 and 1 mg of SIM had a similar cytotoxicity as compared to the HA hydrogel III itself. The sustained release of SIM was observed to occur in the HA hydrogel III loaded with 1 mg of SIM. In vitro and in vivo experiments showed that the HA hydrogel III loaded with 1 mg of SIM had a significant influence on osteogenesis.

Highly porous electrospun nanofibers enhanced by ultrasonication for improved cellular infiltration.

A significant problem that affects tissue-engineered electrospun nanofibrous scaffolds is poor infiltration of cells into the three-dimensional (3D) structure. Physical manipulation can enhance cellular infiltration into electrospun scaffolds. The porosity of electrospun nanofibers was highly enlarged by ultrasonication in an aqueous solution. The porosity and related property changes on a series of nanofibers were observed to be dependent on ultrasonication time and energy. To evaluate cell infiltration into the scaffold, fibroblasts were seeded onto these nanofibers and cultured for different lengths of time. The penetration levels of these cells into the scaffold were monitored using confocal lazer scanning microscopy. The cell infiltration potential was greatly increased with regard to an increase in pore size and porosity. These 3D nanofibrous scaffolds fabricated by an ultrasonication process allowed cells to infiltrate easily into the scaffold. This approach shows great promise for design of cell permeable nanofibrous scaffolds for tissue-engineering applications.

The effect of immobilization of heparin and bone morphogenic protein-2 (BMP-2) to titanium surfaces on inflammation and osteoblast function.

The aim of this study was to investigate biologic function of bone morphorgenic protein-2 (rhBMP-2) immobilized on the heparin-grafted Ti surface. Ti surfaces were first modified by 3-aminopropyltriethoxysilane (ATPES), followed by grafting of heparin. BMP-2 was then immobilized on the heparin-grafted Ti surfaces. Pristine Ti and functionalized Ti surfaces were characterized by X-ray photoelectron spectroscopy (XPS), measurement of water contact angles, and protein adsorption. The biological activity of MG-63 cells on pristine and functionalized Ti surfaces was investigated by cell proliferation assays, measurement of alkaline phosphate (ALP) activity, and determination of calcium deposition. Anti-inflammatory effects were assessed by RT-PCR to measure the transcript levels of IL-6 and TNF-α. XPS revealed that heparin and BMP-2 were successfully grafted and immobilized on the Ti surfaces, respectively. In addition, Ti surfaces with BMP-2 immobilized were more hydrophilic than pristine Ti. Furthermore, BMP-2 immobilized Ti promoted significantly higher ALP activity and calcium deposition by MG-63 cells than pristine Ti. The inflammatory response was also decreased when cells were grown on heparin-grafted, BMP-2-immobilized Ti surfaces. The results of this study suggest that by grafting heparin and immobilizing BMP-2 on Ti surfaces, inflammation can be inhibited and osteoblast function promoted.