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Periodontal disease affects alveolar bone resorption around the involved teeth. To gain bone height, bone graft materials have been widely used with drug carriers. Application of an atmospheric pressure plasma jet (APPJ) treatment is widely studied due to its ability to change surface characteristics without topographical change. The aim of this study is to identify whether the air APPJ (AAPPJ) treatment before drop-wise loading performance could change loaded amount of dexamethasone, and induce increase of cell attachment and proliferation. The results suggested that AAPPJ treatment decreased the contact angle down to about 13 degrees, which increased gradually but significantly lowered at least 4 days compared to no-treated group. After AAPPJ treatment, hydrocarbon was removed with change of zeta potential into positive charge. However, the AAPPJ treatment did not change the quantity or releasing profile of dexamethasone (p > 0.05). Confocal analysis combined with DNA proliferation analysis showed increase of osteoblast attachment and proliferation. Hence, AAPPJ could be a useful pretreatment method before drop-wise loading on HA scaffold with dexamethasone for increase of osteoblast attachment.

We investigated whether a silver coating on an anodic oxidized titania (TiO2) nanotube surface would be useful for preventing infections in dental implants. We used a magnetron sputtering process to deposit Ag nanoparticles onto a TiO2 surface. We studied different sputtering input power densities and maintained other parameters constant. We used scanning electron microscopy, X-ray diffraction, and contact angle measurements to characterize the coated surfaces. Staphylococcus aureus was used to evaluate antibacterial activity. The X-ray diffraction analysis showed peaks that corresponded to metallic Ag, Ti, O, and biocompatible anatase phase TiO2 on the examined surfaces. The contact angles of the Ag nanoparticle-loaded surfaces were significantly lower at 2.5 W/cm2 input power under pulsed direct current mode compared to commercial, untreated Ti surfaces. In vitro antibacterial analysis indicated that a significantly reduced number of S. aureus were detected on an Ag nanoparticle-loaded TiO2 nanotube surface compared to control untreated surfaces. No cytotoxicity was noted, except in the group treated with 5 W/cm2 input power density, which was the highest input of power density we tested for the magnetron sputtering process. Overall, we concluded that it was feasible to create antibacterial Ag nanoparticle-loaded titanium nanotube surfaces with magnetron sputtering.

Noncontact robotic particle grippers with trapping, manipulation, and release functions are highly desired in cell biology and microfluidics. Optoelectric techniques combine optical and electrokinetic effects to create thousands of such individually addressable traps. By projecting reconfigurable light patterns, these techniques can concentrate molecules, as well as manipulate, sort, and electroporate cells in a programmable manner. We describe the underlying physical mechanisms and discuss applications in biology and future prospects of these devices., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

To reduce the incidence of postsurgical bacterial infection that may cause implantation failure at the implant-bone interface, surface treatment of titanium implants with antibiotic materials such as silver (Ag) has been proposed. The purpose of this work was to create TiO2 nanotubes using plasma electrolytic oxidation (PEO), followed by formation of an antibacterial Ag nanostructure coating on the TiO2 nanotube layer using a magnetron sputtering system. PEO was performed on commercially pure Ti sheets. The Ag nanostructure was added onto the resulting TiO2 nanotube using magnetron sputtering at varying deposition rates. Field emission scanning electron microscopy and transmission electron microscopy were used to characterize the surface, and Ag content on the TiO2 nanotube layer was analyzed by X-ray diffraction and X-ray photoelectron spectroscopy. Scanning probe microscopy for surface roughness and contact angle measurement were used to indirectly confirm enhanced TiO2 nanotube hydrophilicity. Antibacterial activity of Ag ions in solution was determined by inductively coupled plasma mass spectrometry and antibacterial testing against Staphylococcus aureus (S. aureus). In vitro, TiO2 nanotubes coated with sputtered Ag resulted in significantly reduced S. aureus. Cell viability assays showed no toxicity for the lowest sputtering time group in the osteoblastic cell line MC3T3-E1. These results suggest that a multinanostructured layer with a biocompatible TiO2 nanotube and antimicrobial Ag coating is a promising biomaterial that can be tailored with magnetron sputtering for optimal performance., (Copyright © 2013 Wiley Periodicals, Inc.)

Objectives: Despite being commonly used as temporary cements in dentistry, there is a lack of studies regarding the cytotoxicity of zinc oxide-eugenol (ZOE) and zinc oxide non-eugenol (ZONE) cements. In addition, cytotoxicity evaluation of the materials often involves animal-based cells. Therefore, in this study, a cytotoxicity evaluation of commercially available ZOE and ZONE cements was carried out using both animal and human-based cells., Materials and Methods: The extraction or dilution of the extraction from four commercially available cements (two zinc oxide-eugenol and two zinc oxide non-eugenol) was tested for cytotoxicity, using three different cells and a water-soluble treatzolium salt assay. The results were confirmed using a confocal laser microscope following calcein AM and ethidium homodimer-1 staining., Results: The results showed that there was a significant difference in cell viability depending on which cell was used, even when the same material was tested. Generally, L929 showed relatively low cell viability with a low EC50 (effective concentration of extracts that caused 50% of cell viability compared to the control) value compared to both HGF-1 and hTERT-hNOF. Such results were also confirmed by a confocal laser microscope., Conclusions: Careful consideration on interpreting the results for cytotoxicity evaluation of ZOE and ZONE cements is needed when different cells are used.

Background: Eccentric viewing training can be successfully applied in the clinical setting based on positive evidence. Nonetheless, published research should be integrated to provide a conclusive perspective of the efficacy of eccentric viewing training., Objective: Meta-analysis was conducted to examine effectiveness of eccentric viewing training on daily visual activities for individuals with age-related macular degeneration (AMD)., Methods: The papers used in this study were located through PubMed, Ovid, ProQuest, EBSCOhost, RISS, and KMbase on studies published between January, 1990 and December, 2012. The keywords for searching were "age-related macular degeneration" and "eccentric viewing", "eccentric fixation", "peripheral vision" or "preferred retinal loci". The effect sizes were calculated using Comprehensive Meta-Analysis 2.0 and interpreted according to Cohen's criteria., Results: A total of 258 studies were found, among which five papers suited the main selection criteria for final analysis. The entire effect size was 0.660 (95% CI, 0.232 ~ 1.088), indicating a moderate effect size of the eccentric viewing training for individuals with AMD in their daily visual activities (p < 0.05)., Conclusions: The results of this study demonstrated the clinical effectiveness of eccentric viewing training for individuals with AMD. This result should be interpreted cautiously, though, given the possibility of publication bias.

This communication first demonstrates bio-compatibility of a recently developed opto-electrokinetic manipulation technique, using microorganisms. Aggregation, patterning, translation, trapping and size-based separation of microorganisms performed with the technique firmly establishes its usefulness for development of a high-performance on-chip bioassay system.

Objective: Cytotoxicity evaluation is an important step in biocompatibility assessment of dental impression materials. Previously, cytotoxicity evaluations were carried out on already set ('set') impression materials for contact time or extraction time of 24 h or longer in duration. However, clinically, dental impression materials are in contact with oral tissue while they are being set ('polymerizing'), for no longer than 10 min. Hence, the aim of this study was to investigate the difference in results between 'polymerizing' and 'set' forms of impression materials as well as the difference in results between longer duration of contact or extraction time (12 or 24 h) and shorter duration of time (15 or 30 min)., Materials and Methods: Seven dental impression materials of different chemical compositions were tested. Two commonly used in vitro tests were used-test on extraction and test by direct contact. Both 'polymerizing' and 'set' forms of impression materials were used with different durations of extraction and contact (15 min, 30 min, 12 h and 24 h)., Results: There were significant (p < 0.05) differences of cell viability and cell proliferation between the 'polymerizing' and 'set' impression materials. Also, significant (p < 0.05) differences were noted with variance in duration of time., Conclusion: In light of the results, it is recommended to use a 'polymerizing' state of dental impression material for cytotoxicity evaluation, with 15 or 30 min of contact between cell and dental impression materials and an extraction time of 15 or 30 min that is more reflective of clinical situations.

In this study, we analyzed the effects of varying concentrations of chitosan (CS) and β-tricalcium phosphate [β-TCP, Ca(3)(PO(4))(2)] on the mechanical and cell-adhesion properties of a collagen (CG) matrix for use in guided bone regeneration (GBR). Three different CS concentrations (0.5, 1, and 2%) and five different contents of β-TCP (0, 17, 29, 38, and 44%) were investigated. The composite membranes were analyzed by scanning electron microscopy and cell-adhesion, flexural-strength, and tear-strength assays. The results show that the cell-adhesion and mechanical properties of the composite membranes improved with increasing β-TCP and CS contents, yielding suitable levels of the adhesion of cells and adequate mechanical stability to ensure successful GBR. The CS adhered to the microsized β-TCP, which was distributed uniformly in the composite membranes. The β-TCP and CS have no negative effect on the cell morphology, viability, and proliferation and possess good biocompatibility. This study demonstrates that β-TCP/CS/CG composite membranes are good candidates for GBR membranes in future applications., (Copyright © 2012 Wiley Periodicals, Inc.)

Aim: To examine the effects of conventional therapy (CT) combined with intensive virtual reality (VR) program on upper extremity function and activities of daily living (ADL) in individuals in the acute stage of stroke., Method: Twenty-six individuals were randomly assigned to the control or experimental group. The control group received CT, while the experimental group received VR training in addition to CT on same day. The Fugl-Meyer Assessment (FMA) and the Manual Function Test (MFT) were used to measure improvement of functioning in the affected limb and the Korean version of the Modified Barthel Index (K-MBI) was conducted to evaluate ADL., Result: In tests of upper extremity functioning, VR group showed significant improvement on FMA and MFT (p< 0.05). In the CT group, only FMA score showed significant change (p< 0.05). ADL performance improved significantly in both groups (p< 0.05). However, there were no significant differences between the two groups in upper extremity function and ADL performance (p> 0.05)., Conclusion: This study observed that VR training has the advantage of improving intended arm function during intensive training for individuals in the acute stage of stroke.

Objective: This study examined whether repetitive transcranial magnetic stimulation applied over the left dorsolateral prefrontal cortex (DLPFC) affected cognition or mood in poststroke patients., Design: The study was a single-center, prospective, double-blind, sham-controlled preliminary study. Eighteen patients (10 males and 8 females; average age, 62.9 yrs) were enrolled. All participants were randomly assigned to one of three treatment groups: low-frequency (1 Hz) stimulation, high-frequency (10 Hz) stimulation, and sham stimulation (control). Each patient underwent 10 consecutive treatment sessions (five times per week for 2 wks). A Computerized Neuropsychological Test was used to evaluate cognitive function, the Tower of London test was used to assess executive function, the Modified Barthel Index score was used to assess activity of daily living function, and the Beck Depression Inventory was used to assess mood status. These evaluations were conducted in all patients before and after treatment., Results: Treatment had no significant effect on any cognitive function parameter, including the Tower of London scores, in any of the three groups. In contrast, high-frequency repetitive transcranial magnetic stimulation resulted in significantly lower Beck Depression Inventory scores compared with baseline and compared with the other two groups. The Modified Barthel Index scores significantly increased in all three groups., Conclusions: These preliminary data suggest that there was a positive effect on mood, but the study was not powered to detect any measurable effect on cognition.

We study a recently demonstrated AC electrokinetic technique for manipulation and concentration of colloidal particles on an electrode surface. The technique uses indium tin oxide (ITO)-based parallel-plate electrodes on which highly localized infrared (1064 nm) laser illumination is shone. We show that the highly localized laser illumination leads to a highly nonuniform heating of the electrode substrate, which in turn drives an electrothermal microvortex resulting in a rapid transport of particles toward the illuminated site. Hundreds of polystyrene particles, with diameters ranging from 2.0 to 0.1 microm, suspended in a low conductivity solution (2.0 mS/m) could be aggregated at selected locations on the electrode by activating the laser illumination at suitable AC frequencies. Subsequent deactivation of the laser illumination causes the particles to scatter, and we explore this dynamical behavior for 1.0 microm particles using Delaunay tessellations and high-speed videography. We establish that drag from the electrothermal microvortex acts against a repulsive force, which decreases with increasing AC frequency, to create stable particle clusters. Moreover, experimentally we show that this particle capturing technique can be characterized by a critical frequency: a frequency at which the captured colloidal particle cluster becomes unstable and particles are carried away into the bulk by the electrothermal microvortex. This critical frequency increases with decreasing particle diameter for similar particles. For 0.1 microm particles, comparison of aggregation at different AC frequencies is achieved by the comparison of fluorescent intensity profiles of the aggregations.

Introduction: Our objectives were to evaluate the force and energy (resilience) delivery properties of thermoplastic overlay orthodontic materials and to determine the changes in force delivery properties after thermocycling or repeated load cycling., Methods: Three types and 3 thicknesses of materials were investigated. Three-point bending-recovery tests were performed at baseline and after cycling procedures. For cycling, the specimens were thermocycled for 1000 cycles or repeatedly deflected by 1 mm for 100 cycles. Vickers hardness was measured to determine the changes after thermocycling or repeated load cycling., Results: The amount of deflection for optimal force delivery was 0.2 to 0.5 mm. Thin material exerted high energy in the deflection range of optimal force delivery. In the deflection ranges of optimal force delivery (0.2-0.5 mm), the force delivery properties after thermocycling were not different from those at the baseline (P >.01) but were different after repeated load cycling (P <.01). Thermocycling and repeated load cycling influenced Vickers hardness significantly., Conclusions: Thin material (0.508 mm) can deliver higher energy than thick materials (0.762 or 1.016 mm, P <.01) of the same brand. Therefore, thin material should be selected in the same brand of material. The effect of repeated deflection during service should be considered.