Objective: The aim of the present, microcomputed tomographic (mCT) and histological study, was to evaluate the effect of surface modification by atmospheric pressure cold plasma (APCP) on vertical guided bone regeneration in a rabbit calvaria model. Material-Methods: The experimental study was conducted on 12 male New Zealand rabbits with healing periods of 45 and 90 days. Following surgical exposure of the calvarium, 4 customized titanium cylindricalders were fixed. Surface modification was achieved by application of APCP on 2 of cylinders (Pþ) in each calvarium and other cylinders were set as control (P-). In both experimental and control groups, one of the cylinders was filled with bone graft (Gþ) while the other one was left empty (G-). To evaluate short term effects, randomly selected 6 animals were sacrificed at the end of 45 days and remaining 6 animals were left for observing long term effects. Histological and mCT evaluations were used to examine new bone formation. Results: In mCT imaging; the bone volume was greater (P < 0.05) in grafted groups than nongrafted groups in both short and long term. The bone height values were significantly different in (P-G-) group than other groups (P < 0.05) in both evaluation periods. The histological evaluations revealed significant differences between PþGþ group and other groups but in long term both plasma treated groups revealed more bone formation than non plasma treated groups. Conclusion: Modification of the surfaces of titanium cylinders by APCP treatment, accelerated the bone regeneration either bone graft used or not in a rabbit calvaria model.@en

Ventilator-associated pneumonia (VAP) is a type of hospital-acquired infection with high mortality and morbidity rates that is seen in critically ill patients who are connected to mechanical ventilators in intensive care units. Conventional infection control measures may remain insufficient for control and prevention of VAP. In the present study, biofilms of most common pathogens, which are responsible for VAP, namely Pseudomonas aeruginosa, Acinetobacter baumannii, Staphylococcus aureus, and Candida albicans, were grown in the lumen of endotracheal tubes (ETs) under low shear to mimic the biofilm formation in clinical settings using the drip flow reactor system. Antibiofilm efficacies of two different plasma treatment methods were tested on the biofilms that were grown in ETs. In the first method, deionized water (DIW), phosphate-buffered saline (PBS) solution, and N-acetylcysteine (NAC) solution were treated with air dielectric barrier discharge (DBD) plasma and then nebulized on the biofilms. In the second method, air plasma afterglow (APA), which was generated using a DBD jet electrode, was flown through the lumen of ETs. Effects of two different plasma treatment methods on biofilms were evaluated using colony-counting and XTT assays. The quantity of extracellular polymeric substance (EPS) was evaluated with the safranin assay. Scanning electron microscopy (SEM) was used to visualize the effect of various plasma treatment methods on biofilms. Cytotoxic effects of two different plasma treatment methods were tested on the human tracheal epithelial cell line. Our results suggest that the nebulized plasma-treated NAC solution had a superior antibiofilm effect as compared with DIW and PBS. Two different plasma treatment methods used effectively inactivated biofilms and significantly reduced the quantity of EPS without a significant damage to the human tracheal epithelial cell line. Furthermore, SEM images showed the inactivation of microbial cells mainly through membrane damage.@en

The bleaching efficacy of common bleaching agents and deionized water treated with non-thermal atmospheric pressure plasma in the pulp chamber for nonvital tooth bleaching was evaluated. A total of 120 extracted human maxillary first incisors were stained using human blood. Teeth were randomly divided into eight groups (n = 15). In the first four groups, teeth were bleached using 35% hydrogen peroxide gel, 37% carbamide peroxide gel, 2:1 (w/v) sodium perborate paste, and deionized water for 30 min. In the remaining groups, bleaching agents were treated with non-thermal atmospheric plasma for 5 min inside the pulp chamber. Overall color changes (∆E) were determined using Commission Internationale de L’Eclairage Lab Colour System. The plasma-assisted tooth bleaching has not increased tooth temperature beyond 37°C. Bleaching efficacies of bleaching agents were significantly improved when treated with non-thermal atmospheric plasma compared to their application (P < 0.05). A remarkable bleaching effect was obtained when bleaching agents were substituted with water and when treated with non-thermal atmospheric plasma. Non-thermal atmospheric plasma treatment could be a novel tool for activation of bleaching agents in the pulp chamber for nonvital tooth bleaching procedure. Moreover, water could be used as a novel bleaching agent when treated with the non-thermal atmospheric plasma to eliminate possible risks which might arise from peroxide-containing agents.

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The purpose of this in vitro study was to evaluate the effect of the non-thermal plasma (NTP) treatment on the wettability and surface roughness of different types of CAD/CAM materials as well as the shear bond strength (SBS) of adhesive resin cement to the treated surfaces. Three different materials, namely; resin nano ceramic, feldspathic ceramic and poly(methyl methacrylate) (PMMA)-based samples were treated with NTP for different time points to evaluate the effect of NTP treatment on the surface properties of CAD/CAM materials. Moreover, surfaces of CAD/CAM materials were visualised with scanning electron microscopy (SEM). A 90-second NTP treatment time was determined as the optimum time for the highest measured wettability, and thus, the 90-second NTP treated samples were used for the SBS test and evaluation of the failure types. Our results revealed the NTP treatment lowered the contact angles and increased the roughness of all tested materials. Moreover, The NTP treatment significantly enhanced the SBS of resin nano ceramic and feldspathic ceramic-based materials. NTP could be considered as a novel pre-treatment method to improve surface properties and the bonding performance of ceramic-based CAD/CAM materials.@en

The ongoing search for better antibacterial wound care dressings has led to the design and fabrication of advanced functional nanomaterials. Taking advantage of electrospinning and cold atmospheric plasma (CAP), free-standing nanofibrous scaffolds are promising for use in novel biomedical applications. Random and aligned polyvinyl alcohol (PVA)/polyacrylic acid (PAA) nanofiber scaffolds are fabricated by electrospinning and treated with CAP. In this study, we investigate the effects of CAP treatment on alignment, hydrophilicity, antibacterial activity, and biocompatibility in determining the surface properties of the nanofibrous scaffolds. The results of vibrational polarization spectroscopy analysis indicate that CAP treatment changes the degree of alignment of the nanofibers. Furthermore, both random and aligned CAP-treated nanofibrous scaffolds show significant antibacterial activity against the E. coli strain. The results of an in vitro scratch assay reveal that CAP treatment of PVA/PAA nanofibers has no toxic effect.@en

This in vitro study aimed to evaluate the effect of nonthermal atmospheric pressure plasma (NAPP)-activated hydrogen peroxide (HP) and deionized water (DW) on enamel microhardness and enamel surface morphology.
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This in vitro study aimed to evaluate the bleaching efficacy and color stability of nonthermal atmospheric pressure plasma (NAPP)-activated 40% hydrogen peroxide (HP) and deionized water (DW). Methods: Two hundred-forty bovine enamel−dentin samples were stained with a coffee solution before bleaching. Samples were randomly divided into 12 (n = 20): (1) HP for 5 minute (HP-5), (2) HP-10, (3) HP-20, (4) Plasma-HP-5, (5) P-HP-10, (6) P-HP-5/HP-15, (7) P-HP-10/HP-10, (8) P-DW-5, (9) P-DW-10, (10) DW-5, (11) DW-10, and (12) DW-20. After bleaching, the samples were re-stained for 48 h using red wine. The color differences measured using a dental spectrophotometer after bleaching and after re-staining were reported as ΔE1 and ΔE2, respectively. The data were analyzed using Kruskal−Wallis and Mann−Whitney U tests (p< 0.05).@en

INTRODUCTION: Barrier membranes are used to create an empty space in the bone defects and to stabilize the blood clot to prevent soft tissue migration. Materials used as barriers should be characterized by some physico-chemical properties to improve biocompatibility, tissue integration, void formation ability and clinical use. The application of atmospheric cold plasma(ACP), which has been shown to increase surface energy and wettability in various materials intended to work, angularly examines and correlates the cellular uptake, protein adsorption and wettability on the surface of the titanium mesh. METHODS: Mesh with dimensions of 1x1 cm and a diameter of 1.6 mm with a thickness of 0.3 mm was treated with air barrier plasma obtained by using a specially produced microsensor pulsed plasma power source. While there is no application in the control group, the mills in the study group were subjected to ACP application with microgeneration plasma generator for 90 seconds. The contact angle measurements were made using a goniometer. RESULTS: The best result in the wettability evaluation was found to be measured in 90 seconds time. There was no statistically significant difference between the amount of protein in samples removed from the incubator after 6 hours of incubation period (p>0.05). There is a statistically significant difference between the groups in the 24-hour time frame (p<0.05). No significant difference was found on day 1 in cell viability (p>0.05) and expression, but a significant difference was found on days 3 and 5 (p<0.05). DISCUSSION AND CONCLUSION: Recently, argon atmospheric pressure plasma has been reported to increase cell diffusion and wettability in titanium discs. In terms of wettability, in accordance with other studies, our work also resulted in the ACP application increasing the wettability and decreasing the contact angle. Long-term effects on cell adhesion and proliferation are seen. Consequently, there is a need for further experimental and clinical studies of the subject. @en

Surgical site infections have a remarkable impact on morbidity, extended hospitalization and mortality. Sutures strongly contribute to development of surgical site infections as they are considered foreign material in the human body. Sutures serve as excellent surfaces for microbial adherence and subsequent colonization, biofilm formation and infection on the site of a surgery. Various antimicrobial sutures have been developed to prevent suture-mediated surgical site infection. However, depending on the site of surgery, antimicrobial sutures may remain ineffective, and antimicrobial agents on them might have drawbacks. Plasma, defined as the fourth state of matter, composed of ionized gas, reactive oxygen and nitrogen species, free radical and neutrals, draws attention for the control and prevention of hospital-acquired infections due to its excellent antimicrobial activities. In the present study, the efficacy of non-thermal atmospheric plasma treatment for prevention of surgical site infections was investigated. First, contaminated poly (glycolic-co-lactic acid), polyglycolic acid, polydioxanone and poly (glycolic acid-co-caprolactone) sutures were treated with non-thermal atmospheric plasma to eradicate contaminating bacteria like Staphylococcus aureus and Escherichia coli. Moreover, sutures were pre-treated with non-thermal atmospheric plasma and then exposed to S. aureus and E. coli. Our results revealed that non-thermal atmospheric plasma treatment effectively eradicates contaminating bacteria on sutures, and non-thermal atmospheric plasma pre-treatment effectively prevents bacterial colonization on sutures without altering their mechanical properties. Chemical characterization of sutures was performed with FT-IR and XPS and results showed that non-thermal atmospheric plasma treatment substantially increased the hydrophilicity of sutures which might be the primary mechanism for the prevention of bacterial colonization. In conclusion, plasma-treated sutures could be considered as novel alternative materials for the control and prevention of surgical site infections.@en

The aim of the present study was to compare antibiofilm efficacies of the laser in contact and noncontact application modes and cold atmospheric plasma (CAP) on Staphylococcus aureus biofilm grown on sandblasted, large grit, acid-etched (SLA) titanium discs as an in vitro model of biofilm eradication on dental implant materials. Methods: S. aureus biofilm was matured on titanium discs for 7 days then, treated with contact and noncontact Er:YAG laser and CAP. Antibiofilm efficacy of laser and plasma treatments were evaluated with colony counting and safranin assays. Surface characteristics of titanium disc were analyzed with scanning electron microscopy and surface roughness measurements. Temperature distribution over titanium discs were presented for the thermal safety assessment of laser and plasma treatments@en

The aim of this study was to investigate the synergistic effect of cold atmospheric plasma (CAP) treatment and RGD peptide coating for enhancing cellular attachment and proliferation over titanium (Ti) surfaces. The surface structure of CAP-treated and RGD peptide-coated Ti discs were characterized by contact angle goniometer and atomic force microscopy. The effect of such surface modification on human bone marrow derived mesenchymal stem cells (hMSCs) adhesion and proliferation was assessed by cell proliferation and DNA content assays. Besides, hMSCs’ adhesion and morphology on surface modified Ti discs were observed via fluorescent and scanning electron microscopy. RGD peptide coating following CAP treatment significantly enhanced cellular adhesion and proliferation among untreated, CAP-treated and RGD peptide-coated Ti discs. The treatment of Ti surfaces with CAP may contribute to improved RGD peptide coating, which enables increased cellular integrations with the Ti surfaces.@en

Antimicrobial activities of non-thermal atmospheric plasma-treated liquids on various bacterial and fungal strains in their planktonic and biofilm forms have been widely reported. Since most of the plasma-treated liquids are water based, they might be washed off certain surfaces and they cannot be applied for the infections of respiratory tract. In the present study we have tested antimicrobial activities of plasma-treated N-acetyl cysteine solution (NAC), phosphate buffered saline (PBS) solution and deionized water when nebulized over planktonic forms of E. coli and S. aureus. Methods. Antimicrobial activities of nebulized plasma-treated liquids were evaluated with zone of inhibition test and colony counting assay. Moreover pH of NAC, PBS solution and deionized water were measured before, after plasma treatment and during nebulization since low pH is well known consequence observed in plasma-treated liquids. Results. Our results have revealed that pH of plasma-treated NAC, PBS solution and DIW decreases after plasma treatment consistent with previous reports and does not change during nebulization. Moreover, antimicrobial activity assessment indicates that nebulized plasma-treated NAC shows the strongest antimicrobial activity, which leads complete inactivation of bacteria for 103 to 106 CFU/ml initial bacterial load and 5-log reduction for 107 CFU/ml initial bacterial load on both E. coli and S. aureus. Conclusions. Plasma-treated liquids could retain their antimicrobial activity during nebulization and nebulization could be considered as a future alternative method for delivery of plasma-treated liquids for respiratory tract infections. @en

Dental implants became very popular in daily dentistry practice especially in
recent decade. However, a long period of osseointegration is the most undesired
disadvantage of this method. Several studies have been published related to shorten the osseointegration time. Atmospheric Cold Plasma (ACP) treatment is applied to titanium implants for shortening the osseointegration time by increasing the surface hydrophilicty and cell adhesion rate. In this study, ACP was applied to the surface of the titanium disc to increase hydrophilicty and osteoblast cell adhesion. Contact angle measurements were performed before and after ACP application. The effects of ACP applicaion on osteoblast cells action were evaluated by immunohistochemistry and SEM analysis. The contact angle measurments were decreased after the ACP application significantly. ACP treatment increased the adhesion and proliferation on titanium disc surface without causing oxidative stress on osteoblastic cells.
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Besides the material type, surface characteristics of titanium based dental implants also affect the treatment success and time. Atmospheric Cold Plasma (ACP) treatment and RGD peptide conjugation methods are applied to titanium implants for shortening the osseointegration time by increasing the surface hydrophilicty and cell adhesion rate. However the comparative effect of these two implant surface modification techniques has yet to be investgated. In the scope of this study, efficacy of the ACP treatment and RGD peptide conjugation methods has been evaluated by determining adhesion and proliferation of rat bone marrow mesencymal stem cells (MSC) on the surface of modified implants. It was shown that comparing the usage of two individual surface modifications, RGD peptid conjugation after ASP treatment of the implant surface had significantly higher MSC adhesion and proliferation.@en

Two stainless steels (SSs)−304 and 316L−as well as a titanium-aluminum-vanadium alloy (Ti6A14V) and ultra-high-molecular-weight polyethylene (UHMWPE) are common metallic and polymeric materials used in medicine for various applications such as bone fracture fixation, dental and cardiac implants, production of medical devices. Implanted materials are highly susceptible to infections that lead may implant failure. The method used to sterilize implant materials plays an important role in the success and performance of an implant. Mechanical properties of UHMWPE are compromised as a consequence of gamma irradiation. Repetitive autoclaving of implants and surgical tools reduces material performance. Also, custom orthopedic prosthesis production requires cheap, on-site, and quick sterilization procedures. In this study we evaluated the inactivation and prevention of biofilm formation of Escherichia coli and Staphylococcus aureus on UHMWPE, a Ti6A14V, 304 SS, and 316L SS surfaces. Plasma treatment of discs was evaluated by an XTT (2,3-bis-(methoxy-4-nitro-5-sulfophenyl)- 2H-tetrazolium-5-carboxanilide]) viability assay, which showed that 95% of both bacterial biofilms were inactivated after 3 minutes of plasma treatment. For the biofilm prevention tests, UHMWPE, Ti6A14V, 304 SS, and 316L SS discs were first treated with nonthermal dielectric barrier discharge plasma; then, 1-day-old biofilms of E. coli and S. aureus were grown on the disc surfaces, and biofilm formation was similarly evaluated using an XTT assay. Plasma treatment of implant surfaces prevents biofilm formation up to 50%. Safranin assay, which was used to evaluate extracellular polymeric substances, also has shown that plasma treatment of UHMWPE, Ti6A14V, 304 SS, and 316L SS discs not only inactivates biofilms but also but also disrupts extracellular polymeric substances that are secreted by bacteria during biofilm growth.@en