Abstract: Many dental clinical implant studies have fo- cused on the success of endosseous implants with a variety of surface characteristics. Most of the surface alterations have been aimed at achieving greater bone-to-implant con- tact... more
Abstract: Many dental clinical implant studies have fo- cused on the success of endosseous implants with a variety of surface characteristics. Most of the surface alterations have been aimed at achieving greater bone-to-implant con- tact as determined histometrically at the light microscopic ...
PMMA beam specimens were tested in four-point bending to determine if' the bending strength of acrylic bone cement, as used in posterior spinal fusion, could be improved by metal-wire reinforcement. The result showed that the... more
PMMA beam specimens were tested in four-point bending to determine if' the bending strength of acrylic bone cement, as used in posterior spinal fusion, could be improved by metal-wire reinforcement. The result showed that the load-carrying capacities of 1-and 0.5-mm diam ...
We aimed to evaluate the in vitro osteogenic and osteoinductive potentials of BioS-2P and its ability to promote in vivo bone repair. To investigate osteogenic potential, UMR-106 osteoblastic cells were cultured on BioS-2P and Bioglass... more
We aimed to evaluate the in vitro osteogenic and osteoinductive potentials of BioS-2P and its ability to promote in vivo bone repair. To investigate osteogenic potential, UMR-106 osteoblastic cells were cultured on BioS-2P and Bioglass 45S5 discs in osteogenic medium. The osteoinductive potential was evaluated using mesenchymal stem cells (MSCs) cultured on BioS-2P, Bioglass 45S5 and polystyrene in non-osteogenic medium. Rat bone calvarial defects were implanted with BioS-2P scaffolds alone or seeded with MSCs. UMR-106 proliferation was similar for both materials, while alkaline phosphatase (ALP) activity and mineralization were higher for BioS-2P. Bone sialoprotein (BSP), RUNX2 and osteopontin (OPN) gene expression and BSP, OPN, ALP and RUNX2 protein expression were higher on BioS-2P. For MSCs, ALP activity was higher on Bioglass 45S5 than on BioS-2P and was lower on polystyrene. All genes were highly expressed on bioactive glasses compared to polystyrene. BioS-2P scaffolds promote...
Polyethylene glycol diacrylate (PEGDA) is an important class of photosensitive polymer with many tissue engineering applications. This study compared PEGDA and polycaprolactone (PCL) nanofiber matrix (NFM) coated PEGDA, referred to as... more
Polyethylene glycol diacrylate (PEGDA) is an important class of photosensitive polymer with many tissue engineering applications. This study compared PEGDA and polycaprolactone (PCL) nanofiber matrix (NFM) coated PEGDA, referred to as PCL-PEGDA, scaffolds for their application in multiple tissue repair such as articular cartilage, nucleus pulposus of the intervertebral disc (IVD). We examined each scaffold morphology, porosity, swelling ratio, degradation, mechanical strength, and in vitro cytocompatibility properties. A defect was created in Sprague Dawley rat tail IVD by scraping native cartilage tissue and disc space, then implanting the scaffolds in the disc space for 4 weeks to evaluate in vivo efficacy of multi-tissue repair. Maintenance of disc height and creation of a new cell matrix was assessed to evaluate each scaffold’s ability to repair the tissue defect. Although both PEGDA and PCL-PEGDA scaffolds showed similar porosity ∼73%, we observed distinct topographical charact...
The clinical use of plasma-sprayed hydroxyapatite (HA) coatings on metal implants has aroused as many controversies as interests over the last decade. Although faster and stronger fixation and more bone growth have been revealed, the... more
The term "nanoleakage" has been introduced to explain a penetration pathway within hybrid layers of the dentin-composite junction in the absence of gap formation. This phenomenon is argued in the literature to be a risk... more
The term "nanoleakage" has been introduced to explain a penetration pathway within hybrid layers of the dentin-composite junction in the absence of gap formation. This phenomenon is argued in the literature to be a risk factor for the quality of the dentin bonding. NaOCl is a well-known agent used to remove collagen layers that are exposed after acid etching. The purpose of this study was to determine the influence of an NaOCl treatment of dentin to the formation of nanoleakage. Class V cavities were prepared in 40 human molars with the cervical margins located in dentin. After etching with phosphoric acid, 20 samples were treated with 10% NaOCl for 60 s, and 20 samples were used as control. Composite restorations were placed using two different bonding systems. The specimen were exposed in silver nitrate solution and then in developer. After embedding, the teeth were sectioned, dried, coated with gold, and analyzed by SEM. For all the specimen in the control group, backscatter images indicated a silver penetration within the hybrid layer. There was no penetration of silver detectable in the teeth that were treated with NaOCl. We conclude that the removal of the collagen layer by using NaOCl avoids the formation of nanoleakages with the materials tested.
Electrospinning is a versatile technique for generating a mat of continuous fibers with diameters from a few nanometers to several micrometers. The diversity of electrospinnable materials, and the unique features associated with... more
Electrospinning is a versatile technique for generating a mat of continuous fibers with diameters from a few nanometers to several micrometers. The diversity of electrospinnable materials, and the unique features associated with electro-spun fibers make this technique and its resultant structures attractive for applications in the biomedical field. This article presents an overview of this technique focusing on its application for tissue engineering. In particular, the advantages and disadvantages of using an electrospinning mat for biomedical applications are discussed. It reviews the different available electrospinning configurations, detailing how the different process variables and material types determine the obtained fibers characteristics. Then a description of how nanofiber based scaffolds offer great promise in the regener-ation or function restoration of damaged or diseased bones, muscles or nervous tissue is reported. Different methods for incorporating active agents on nanofibers and controlling their release mechanisms are also reviewed. The review concludes with some personal perspectives on the future work to be done in order to include electrospinning technique in the industrial development of biomedical materials.
The manufacture of 3D scaffolds with specific controlled porous architecture, defined microstructure and an adjustable degradation profile was achieved using two-photon polymerization (TPP) with a size of 2 × 4 × 2 mm(3). Scaffolds... more
The manufacture of 3D scaffolds with specific controlled porous architecture, defined microstructure and an adjustable degradation profile was achieved using two-photon polymerization (TPP) with a size of 2 × 4 × 2 mm(3). Scaffolds made from poly(D,L-lactide-co-ɛ-caprolactone) copolymer with varying lactic acid (LA) and ɛ -caprolactone (CL) ratios (LC16:4, 18:2 and 9:1) were generated via ring-opening-polymerization and photoactivation. The reactivity was quantified using photo-DSC, yielding a double bond conversion ranging from 70% to 90%. The pore sizes for all LC scaffolds were see 300 μm and throat sizes varied from 152 to 177 μm. In vitro degradation was conducted at different temperatures; 37, 50 and 65 °C. Change in compressive properties immersed at 37 °C over time was also measured. Variations in thermal, degradation and mechanical properties of the LC scaffolds were related to the LA/CL ratio. Scaffold LC16:4 showed significantly lower glass transition temperature (T g...
Bone grafts are vital for replacing or repairing skeletal tissue compromised by injury or disease. The current gold standards for bone graftsautografts taken directly from the patient or processed allografts taken from a cadaveric... more
Bone grafts are vital for replacing or repairing skeletal tissue compromised by injury or disease. The current gold standards for bone graftsautografts taken directly from the patient or processed allografts taken from a cadaveric donorare limited in availability, and can ...
Collagen is commonly used as a tissue-engineering scaffold, yet its in vivo applications are limited by a deficiency in mechanical strength. The purpose of this work was to explore the utilization of a unique enzymatic crosslinking... more
Collagen is commonly used as a tissue-engineering scaffold, yet its in vivo applications are limited by a deficiency in mechanical strength. The purpose of this work was to explore the utilization of a unique enzymatic crosslinking procedure aimed at improving the mechanical properties of collagen-based scaffold materials. Type I bovine collagen gel was crosslinked by transglutaminase, which selectively mediates the chemical reaction between glutamine and lysine residues on adjacent protein fibers, thus providing covalent ...