No-ozone cold plasma induces apoptosis in human neuroblastoma cell line via increased intracellular reactive oxygen species (ROS).

BACKGROUND: This study aimed to evaluate the effect of argon-based No-ozone Cold Plasma (NCP) on neuroblastoma cancer cell apoptosis. METHODS: Experiments were performed with SK-N-SH and HS 68. Cell cultures were treated with NCP for 1, 3, and 5 min. NCP was applied using three different strategies: direct NCP application to cell cultures, to only media, and to only cells. Evaluation of cell viability and the level of the reactive oxygen species (ROS) was performed. N-acetyl-L-cysteine (NAC) was also used to antagonize intracellular ROS. Cleaved caspase 3, PARP, aquaporin (AQP) 3 and 8 were detected. RESULTS: NCP induced a gradual decrease in the SK-N-SH cell viability. In contrast, the viability of HS 68 cells did not change. SK-N-SH cells viability was reduced the most when the only media-NCP application strategy was employed. Intracellular ROS levels were significantly increased with time. Cleaved caspase 3 and PARP were increased at 6 h after NCP application. SK-N-SH cells remained viable with NAC after NCP application. AQP 3 and 8 were over-expressed in SK-N-SH cells. CONCLUSION: These findings demonstrate the anti-cancer effect of NCP on neuroblastoma cells. NCP enhanced the selective apoptosis of neuroblastoma cells due to the increased intracellular ROS.

Antimicrobial Effects of Edible Mixed Herbal Extracts on Oral Microorganisms: An In Vitro Study.

Background and Objectives: The oral cavity is inhabited by pathogenic bacteria, whose growth can be inhibited by synthetic oral drugs, including antibiotics and other chemical compounds. Natural antimicrobial substances that elicit fewer negative side effects may serve as alternatives to synthetic agents for long-term use. Thus, the aim of this study was to evaluate the effects of edible mixed herbal extracts on the growth of oral pathogenic bacteria. Materials and Methods: The yield of each herbal extract was as follows: 5% Schizonepeta tenuifolia Briq (STB), 10.94% Mentha piperascens (MP), 5.47% Acanthopanax sessiliflorus Seem (AS), and 10.66% Glycyrrhiza uralensis (GU). The herbal extracts used included 0.5 mg/mL STB, 1.5 mg/mL MP, 1.5 mg/mL AS, and 2.0 mg/mL GU. Antimicrobial tests, morphological analyses (using scanning electron microscopy), microbial surface hydrophobicity measurements, and oral malodor reduction tests were performed using each extract. Statistical analyses were performed with IBM® SPSS® (version 24), using paired t-tests. Results: The mixed herbal extracts significantly inhibited the growth of Streptococcus mutans, Enterococcus faecalis, Candida albicans, and Porphyromonas gingivalis compared to the control (p < 0.001). Scanning electron microscopy results further revealed altered cellular morphology in the groups treated with the mixed herbal extracts. Additionally, the hydrophobicity assay results showed that the mixed herbal extracts reduced the oral adhesion capacities of bacteria (p < 0.001). Administration of the mixed herbal extracts also reduced the levels of volatile sulfur compounds, the main contributors to oral malodor (p < 0.001). Conclusions: Edible mixed herbal extracts can effectively eliminate oral pathogens and may be useful for improving oral health. The herbal extracts used were effective against all species of oral pathogens studied in this report.

Evaluation of the Antifungal Effect of Rhus verniciflua Stokes Extract for Oral Application Potential.

Background and Objectives: This study confirms the possibility of using Rhus verniciflua Stokes (RVS) extract as a natural treatment for oral candidiasis. Materials and Methods: RVS was extracted with 70% ethanol to examine the antioxidant activity through polyphenol, flavonoid content, and DPPH (1,1-diphenyl-2-picrylhydrazyl). To evaluate the antifungal effect against Candida albicans (C. albicans; KCTC 7965/ATCC 10231) and evaluate the stability of RVS, a water-soluble tetrazolium salt (WST-1) assay was performed in human keratinocytes (HaCaT). Results: The findings revealed that RVS extract has fairly high antioxidant activity. The clear zones of the RVS extract against C. albicans increased in diameter due to the inhibition of fungal growth at higher concentrations. Treatment with the 1.25 mg/mL RVS extract had a more than 99% antifungal effect against C. albicans, and the 20 mg/mL RVS extract had a 100% antifungal effect. The WST-1 assay showed that the RVS extract induced low cell viability in the HaCaT cells, which inhibited their proliferation, and the RVS extract is also toxic to normal cells. Conclusions: Although the RVS extract with high antioxidant activity showed clear antifungal activity against C. albicans, it exhibited a low survival rate. Therefore, the development of a safe natural antibiotic is necessary.

Topical Application of No-Ozone Cold Plasma in Combination with Vitamin C Reduced Skin Redness and Pigmentation of UV-Irradiated Mice.

Ultraviolet (UV) is the main cause of sunburn on the skin as it induces erythema and accelerates pigmentation. Vitamin C is one of the most frequently used compounds to reduce UV-induced skin pigmentation, but it has limitations in absorption through the skin. In this study, we tested whether a no-ozone cold plasma (NCP) treatment can improve UV-irradiated skin by helping the action of Vitamin C. For this, among five groups of HRM-2 hairless mice, four groups of mice were subjected to UVB irradiation, and three groups of UVB-treated mice were treated with NCP, Vitamin C, and NCP + Vitamin C, respectively. For evaluating the effect of each treatment, the melanin and erythema index was measured during animal experiments. Histological changes were monitored by performing H&E and MTS and IHC against tyrosinase and melanin. As a result, the naturally recovered mice showed a 28-point decrease in the melanin index, whereas a decrease of around 88, 74.3, and 106 points was detected in NCP-, Vitamin C-, and NCP + vitamin C-treated mice, respectively. Likewise, only a 39-point reduction in the erythema index was monitored in naturally recovered mice, but the NCP-, vitamin C-, and NCP + vitamin C-treated mice showed a 87.3-, 77-, and 111-point reduction, respectively. Interestingly, the skin tissues of the mice treated with NCP in combination with Vitamin C mostly recovered from UVB-induced damage. Altogether, this study elucidated the beneficial effect of the treatment of NCP in combination with Vitamin C on the UVB-irradiated skin, which might be helpful for treating sunburn on the skin.

Editorials for 'Advances in Cold Plasma in Biomedicines'.

Research in the field of plasma medicine has provided many explanations for various phenomena, as well as the involvement of the chemical elements of plasma; however, it still lacks in biological mechanism analyses [...].

Effect of No-ozone Cold Plasma on Regeneration after Crushed Mental Nerve Injury in rats.

Background: This experimental research aimed to determine whether No-ozone Cold Plasma (NCP) has regenerative effect on crushed injured sensory nerves in a rat model (Wistar A) and to evaluate whether NCP can be used as an alternative treatment method for sensory nerve injury in the oral-maxillofacial region. Methods: A total of 10 Wistar A rats were used for this experiment. They were divided into three groups according to whether the mental nerve of the left mandible was injured and NCP was applied or not: group 1 (n=3) (non-mental nerve damage, non-MD) - the left mental nerve was exposed and non-damaged; group 2 (n=3) (mental nerve damage, MD) - the left mental nerve was exposed and damaged, NCP was not applied; and group 3 (n=4) (mental nerve damage and NCP, MD-NCP) - the left mental nerve was exposed and damaged, NCP was applied with regular intervals (three times a week). Results: For the behavior analysis, von Frey test was used. Furthermore, the nerve tissues were examined with hematoxylin and eosin (H&E) staining, and the extent of neurorecovery was evaluated with the immunofluorescence staining of certain markers. The behavioral analysis showed that the function recovery sensory nerve was faster in group 3 (MD-NCP). In the histomorphologic and immunofluorescence analyses, the expression of the factors involved in neurorecovery was much higher in group 3 than in group 2 (MD). Conclusions: The expeditious recovery of sensory nerve function as well as the higher expression of the factors indicating nerve function recovery in the NCP-treated group suggest that NCP has a positive effect on regeneration after sensory nerve crushing injury. Therefore, in the case of sensory impairment of the oral-maxillofacial region, no-ozone cold plasma can be applied for therapeutic effect.

Anti-Cancer Activity of the Combinational Treatment of Noozone Cold Plasma with p-FAK Antibody-Conjugated Gold Nanoparticles in OSCC Xenograft Mice.

Oral squamous cell cancer (OSCC) is the most common type of oral cancer (about 80-90% of cases) and various research is being done to cure the disease. This paper aims to verify whether treatment with no-ozone cold plasma (NCP), which is designed for safe usage of the plasma on oral cavities, in combination with gold nanoparticles conjugated with p-FAK antibody (p-FAK/GNP) can trigger the selective and instant killing of SCC-25 cells both in vitro and in vivo. When SCC25 and HaCaT cells are exposed to p-FAK/GNP+NCP, the instant cell death was observed only in SCC25 cells. Such p-FAK/GNP+NCP-mediated cell death was observed only when NCP was directly treated on SCC25 harboring p-FAK/GNP. During NCP treatment, the removal of charged particles from NCP using grounded electric mesh radically decreased the p-FAK/GNP+NCP-mediated cell death. This p-FAK/GNP+NCP-mediated selective cell death of OSCC was also observed in mice xenograft models using SCC25 cells. The mere treatment of p-FAK/GNP and NCP on the xenograft tumor slowly decreased the size of the tumor, and only about 50% of the tumor remained at the end of the experiment. On the other hand, 1 week of p-FAK/GNP+NCP treatment was enough to reduce half of the tumor size, and most of tumor tissue had vanished at the end. An analysis of isolated tissues showed that in the case of individual treatment with p-FAK/GNP or NCP, the cancer cell population was reduced due to apoptotic cell death. However, in the case of p-FAK/GNP+NCP, apoptotic cell death was unobserved, and most tissues were composed of collagen. Thus, this paper suggests the possibility of p-FAK/GNP+NCP as a new method for treating OSCC.

Non-thermal plasma directly accelerates neuronal proliferation by stimulating axon formation.

Among the various methods, Non Thermal Plasma (NTP) has been recently introduced and is being studied to recover the damaged nerve. In the recent years, several studies have suggested that NTP accelerates nerve cell regeneration, but the mechanism remains unknown. This study evaluated the effect of NTP on neuronal proliferation in SH-SY5Y (Human neuroblastoma cells) cells differentiated by retinoic acid (RA) and investigated the mechanism by which NTP promotes cell proliferation. We analyzed the morphology of differentiated SH-SY5Y cells, and performed western blot analysis and reverse transcription polymerase chain reaction (RT-PCR). Immunofluorescence analysis was performed in an in vivo study by categorizing Wistar A rats into three groups: non-nerve damage (Non-ND), nerve damage (ND), and nerve damage + NTP treatment (ND + NTP). The cell morphology analysis revealed that the number of cells increased and axonal elongation progressed after NTP treatment. In addition, western blots indicated that tau expression increased significantly after NTP treatment. The RT-PCR results revealed that the expression of tau, wnt3a, and ß-catenin increased after NTP treatment. The in vivo immunofluorescence assay showed that NTP increased the markers for tau and S100B while regulating the over-expression of MAP2 and GAP43. NTP treatment accelerated cell proliferation and regeneration of damaged neurons in differentiated SH-SY5Y cells. These results establish the fact of NTP as a noninvasive and effective treatment for nerve injury.

No-ozone cold plasma can kill oral pathogenic microbes in H2O2-dependent and independent manner.

To apply the sterilisation effect of low-temperature plasma to the oral cavity, the issue of ozone from plasma must be addressed. In this study, a new technology for generating cold plasma with almost no ozone is developed and is named Nozone (no-ozone) Cold Plasma (NCP) technology. The antimicrobial efficacy of the NCP against four oral pathogens is tested, and its specific mechanism is elucidated. The treatment of NCP on oral pathogenic microbes on a solid medium generated a growth inhibition zone. When NCP is applied to oral pathogens in a liquid medium, the growth of microbes decreased by more than 105 colony forming units, and the bactericidal effect of NCP remained after the installation of dental tips. The bactericidal effect of NCP in the liquid medium is due to the increase in hydrogen peroxide levels in the medium. However, the bactericidal effect of NCP in the solid medium depends on the charged elements of the NCP. Furthermore, the surface bactericidal efficiency of the dental-tip-installed NCP is proportional to the pore size of the tips and inversely proportional to the length of the tips. Overall, we expect this NCP device to be widely used in dentistry in the near future.

Enhancement of Osteoblast Differentiation Using No-Ozone Cold Plasma on Human Periodontal Ligament Cells.

Periodontitis is an inflammatory disease that leads to periodontal tissue destruction and bone resorption. Proliferation and differentiation of cells capable of differentiating into osteoblasts is important for reconstructing periodontal tissues destroyed by periodontitis. In this study, the effects of the nozone (no-ozone) cold plasma (NCP) treatment on osteoblastic differentiation in periodontal ligament (PDL) cells were investigated. To test the toxicity of NCP on PDL cells, various NCP treatment methods and durations were tested, and time-dependent cell proliferation was analyzed using a water-soluble tetrazolium salts-1 assay. To determine the effect of NCP on PDL cell differentiation, the cells were provided with osteogenic media immediately after an NCP treatment to induce differentiation; the cells were then analyzed using alkaline phosphatase (ALP) staining, an ALP activity assay, real time PCR, and Alizarin Red S staining. The NCP treatment without toxicity on PDL cells was the condition of 1-min NCP treatment immediately followed by the replacement with fresh media. NCP increased ALP, osteocalcin, osteonectin, and osteopontin expression, as well as mineralization nodule formation. NCP treatment promotes osteoblastic differentiation of PDL cells; therefore, it may be beneficial for treating periodontitis.

Influence of Non-Thermal Atmospheric Pressure Plasma Treatment on Retentive Strength between Zirconia Crown and Titanium Implant Abutment.

The aim of this study is to investigate the effect of non-thermal atmospheric pressure plasma (NTP) on retentive strength (RS) between the zirconia crown and the titanium implant abutment using self-adhesive resin cement. Surface free energy (SFE) was calculated on 24 cube-shaped zirconia blocks, and RS was measured on 120 zirconia crown-titanium abutment assemblies bonded with G-CEM LinkAce. The groups were categorized according to the zirconia surface treatment as follows: Control (no surface treatment), NTP, Si (Silane), NTP + Si, Pr (Z-Prime Plus), and NTP + Pr. Half of the RS test assemblies were aged by thermocycling for 5000 cycles at 5-55 °C. The SFE was calculated using the Owens-Wendt method, and the RS was measured using a universal testing machine at the maximum load until failure. One-way analysis of variance (ANOVA) with post-hoc Tukey honestly significant difference (HSD) was performed to evaluate the effect of surface treatments on the SFE and RS. Independent sample t-test was used to compare the RS according to thermocycling (p < 0.05). For the SFE analysis, the NTP group had a significantly higher SFE value than the Control group (p < 0.05). For the RS test, in non-thermocycling, the NTP group showed a significantly higher RS value than the Control group (p < 0.05). However, in thermocycling, there was no significant difference between the Control and NTP groups (p > 0.05). In non-thermocycling, comparing with the NTP + Si or NTP + Pr group, there was no significant difference from the Si or Pr group, respectively (p > 0.05). Conversely, in thermocycling, the NTP + Si and NTP + Pr group had significantly lower RS than the Si and Pr group, respectively (p < 0.05). These results suggest that NTP single treatment for the zirconia crown increases the initial RS but has little effect on the long-term RS. Applied with Silane or Z-Prime Plus, NTP pre-treatment has no positive effect on the RS.

The effect of autogenous tooth bone graft material without organic matter and type I collagen treatment on bone regeneration.

OBJECTIVES: The aim of this study is to examine the effect of particulate autogenous tooth graft removed with organic matter and type I collagen addition on bone regeneration and to validate the possibility of useful allograft material for jaw defects. MATERIAL AND METHODS: Autogenous tooth bone maker (Korean Dental Solution® KOREA) made particulate autogenous tooth not including organic matter. We used to the developed tooth grafts for experiment. Cell adhesion test with hemacytometer and energy dispersive X-ray spectroscopy (Supra40 VP®, Carl Zeiss, Germany) analysis about the particulate autogenous tooth and type I collagen were performed. Rabbits were divided into three groups: bone graft with organic matter (OM) removing particulate autogenous tooth group, bone graft with OM removing particulate autogenous tooth and type I collagen group, and a control group. Bone grafting was performed in rabbit's calvaria. The rabbits were sacrificed at different interval at 1, 2, 4, and 6 weeks after bone grafting for the histopathologic observation and observed the effect of bone regeneration by SEM, H-E & Masson stains, osteocalcin IHC staining. RESULT: In vitro cytopathological study showed affinity for cells, cell attachment pattern, and cell proliferation in the order of control group, OM-removed and collagen-treated group, OM-removed particulate autogenous tooth group. The results of the degree of mineralization were opposite to those of the previous cell experimental results, and the OM-removed group, OM-removed group and collagen-treated group were relatively higher than the control group. Histopathologic analysis showed that vascularization and neonatal bone formation were higher in particulate autogenous tooth group with removing OM and with addition of collagen than control group and group of OM removed only. Immunohistochemical analysis showed that osteocalcin (OSC) expression was not observed in the control group, but at 4 weeks groups, OSC expression was observed the OM removed and OM-removed-collagen-treated particulate autogenous tooth, and the degree of expression was somewhat stronger in group of the OM removed and collagen additionally treated particulate autogenous tooth. CONCLUSION: Particles that do not contain organic matter, the saint tooth, was responsible for sufficient bone graft material through the role of space maintenance and bone conduction, and further improved bone formation ability through additional collagen treatment. Therefore, research on various extracellular substrates and autologous bone grafting materials is necessary, and through this, it is possible to lay the foundation for a new type of autologous bone grafting material with excellent academic and technical utility.

Protective effects of non-thermal plasma on triethylene glycol dimethacrylate-induced damage in odontoblast-like MDPC-23 cells.

AIM: To evaluate whether the use of non-thermal plasma (NTP) could reduce triethylene glycol dimethacrylate (TEGDMA)-mediated damage in MDPC-23 cells. METHODOLOGY: The effects of NTP and TEGDMA on MDPC-23 cell proliferation were tested using WST-1 assays after pretreatment with NTP for 1 min and exposure to TEGDMA. Live/Dead assays were used to visualize cell death. To monitor the effects of NTP and TEGDMA on the cell cycle and apoptotic cell death, flow cytometry was performed. Western blotting was used to assess changes in protein levels mediated by NTP and TEGDMA treatment, and enzyme-linked immunosorbent assays were performed to evaluate the effects of NTP and TEGDMA on prostaglandin E2 (PGE2 ) expression. One-way analysis of variance and Duncan's post hoc tests were used for statistical analysis. RESULTS: NTP treatment effectively protected cells from TEGDMA-mediated cell damage and blocked TEGDMA-mediated cell growth inhibition (p < .05). NTP appeared to protect cells from death (p < .05) and blocked TEGDMA-mediated apoptotic cell death. Additionally, NTP reduced TEGDMA-mediated apoptotic activation of poly (ADP) ribose polymerase-1 and caspase-3 (p < .05). Furthermore, NTP effectively reduced TEGDMA-mediated expression of cyclooxygenase-2 and PGE2 proteins by inhibiting nuclear factor-κB protein expression (p < .05). CONCLUSIONS: NTP alleviated TEGDMA-mediated adverse effects by reducing cytotoxicity and inflammatory reactions in cells exposed to TEGDMA.

The Whitening Effect and Histological Safety of Nonthermal Atmospheric Plasma Inducing Tooth Bleaching.

Various light sources have been applied to enhance the bleaching effect. This study was to identify the histological evaluation in oral soft tissues, as well as tooth color change after tooth bleaching by nonthermal atmospheric pressure plasma (NAPP). Nine New Zealand adult female rabbits were randomly divided into three groups (n = 3): group 1 received no treatment; group 2 was treated with NAPP and 15% carbamide peroxide (CP), which contains 5.4% H2O2, and group 3 was treated with 15% CP without NAPP. Color change (ΔE) was measured using the Shade Eye NCC colorimeter. Animals were euthanized one day later to analyze the histological responses occurring in oral soft tissues, including pulp, gingiva, tongue, buccal mucosa, and hard and soft palates. Changes in all samples were analyzed by hematoxylin and eosin staining and Masson's trichrome. Teeth treated with plasma showed higher ΔE than that obtained with bleaching agents alone. Overall, the histological characteristics observed no appreciable changes. The combinational treatment of plasma had not indicated inflammatory responses as well as thermal damages. NAPP did not cause histological damage in oral soft tissues during tooth bleaching. We suggest that NAPP could be a novel alternative energy source to conventional light sources for tooth bleaching.

Non-thermal plasma application enhances the recovery of transected sciatic nerves in rats.

This experimental research aimed to investigate the effects of non-thermal plasma on nerve regeneration after transected nerve damage using the sciatic nerve in Wistar albino (A) rats. The experiments were performed on 27 Wistar A rats. The rats underwent surgery for right sciatic nerve exposure and were divided into three groups (each group, n = 9) according to sciatic nerve transected injury (SNTI) and non-thermal plasma application: a non-nerve damage (non-ND) group, a only nerve damage without non-thermal plasma application (ND) group, and a nerve damage with non-thermal plasma application (ND + NTP) group. Subsequent to SNTI and immediate suture, non-thermal plasma was administered three times per week for eight weeks. Evaluation for functional recovery was performed using the static sciatic index measured over the full treatment period of eight weeks. The sciatic nerve specimens were obtained after euthanasia and third day from the last non-thermal plasma application. The sciatic nerve tissues were subjected to histological analysis. Behavior analysis presented that the ND + NTP group showed improved static sciatic index compared with the nerve damage group. Histopathological findings demonstrated that the ND + NTP group had more dense Schwann cells and well-established continuity of nerve fibers, greater than the nerve damage group. Immunohistochemistry showed that the ND + NTP group had increased levels of markers for microtubule-associated protein 2 (MAP2), tau, S100 calcium-binding protein B, and neurofilament-200 and regulated the overexpression of CD68 and MAP2. These results indicated that non-thermal plasma enhanced the motor function and restored the neuronal structure by accelerating myelination and axonal regeneration. Additionally, non-thermal plasma was confirmed to have a positive effect on the recovery of SNTI in rats.

Gold nanoparticles conjugated with programmed death-ligand 1 antibodies induce apoptosis of SCC-25 oral squamous cell carcinoma cells via programmed death-ligand 1/signal transducer and transcription 3 pathway.

OBJECTIVE: Objective of this study is to test the anti-cancer effect of the gold nanoparticles conjugated with programmed death-ligand 1 (PD-L1) specific antibodies (PDL1-GNP), on oral squamous cell carcinoma. DESIGN: To test the effect of PDL1-GNP on oral squamous cell carcinoma, SCC-25 cells, a type of human oral squamous cell carcinoma which were isolated from human tongue, and HaCaT human keratinocytes as normal cell control, were used. Cell viability was tested by the water-soluble tetrazolium-1 and live/dead assays, while apoptotic cell death of SCC-25 cells were monitored by immunofluorescent staining and flow cytometry. The molecular changes during PDL1-GNP-mediated apoptosis were analyzed using Western blot analysis. RESULTS: PDL1-GNP treatment effectively decreased the growth of SCC-25 cells but not HaCaT cells. The results of the confocal microscopic assay showed that PDL1-GNP specifically bound to the SCC-25 cell membrane. Furthermore, the results of the live/dead, cytochrome c release assays and flow cytometry indicated PDL1-GNP-mediated apoptotic cell death of SCC-25 cells. PDL1-GNP-treated SCC-25 cells showed a phenotype with increased apoptotic proteins, including cleaved form of caspase-3, caspase-9, and poly (ADP-ribose) polymerase 1 (PARP1). PDL1-GNP treatment also effectively decreased B-cell lymphoma 2 (Bcl-2) and PD-L1 protein expression. Phosphorylation of signal transducer and transcription 3 (STAT3) was significantly increased after PDL1-GNP treatment on SCC-25 cells. CONCLUSIONS: PDL1-GNP treatment induced SCC-25 cell apoptosis possibly by inhibiting the function of the PD-L1 protein, since PD-L1 blocks STAT3 phosphorylation, which promotes apoptotic cell death.

Effect of Non-Thermal Atmospheric Pressure Plasma (NTP) and Zirconia Primer Treatment on Shear Bond Strength between Y-TZP and Resin Cement.

The purpose of this study was to investigate the effect of non-thermal atmospheric pressure plasma (NTP) treatment on the sandblasting of mechanical method and zirconia primer of chemical method used to increase the bond strength between zirconia and resin cement. In this study, Y-TZP was divided into 4 groups according to the surface treatment methods as follows: Zirconia primer (Pr), NTP + Zirconia primer (NTP + Pr), Sandblasting + Zirconia primer (Sb + Pr), Sandblasting + NTP + Zirconia primer (Sb + NTP + Pr). Then, two types of resin cement (G-CEM LinkAce and Rely X-U200) were used to measure the shear bond strength (SBS) and they were divided into non-thermal cycling group and thermal cycling group for aging effect. Statistical analyses were performed using the Kruskal-Wallis test and Mann-Whitney U test. The result of the surface energy (SE), there was no significant difference among the groups (p > 0.05). As a result of the SBS test, the Sb + Pr group had a significantly higher SBS value than the other groups regardless of the resin cement type (p < 0.05), and the decrease rate after thermal cycling treatment was the lowest. On the other hand, the NTP + Pr group showed significantly lower SBS values than the other groups except for the case of using Rely X-U200 (p < 0.05), and the reduction rate after thermal cycling was the highest. The Sb + NTP + Pr group did not differ significantly from the Pr group (p > 0.05). Within the limitations of two successive studies, treatment with NTP after sandblasting used for mechanical bond strength showed a positive effect on initial SBS. However, when NTP was treated before the zirconia primer used for the chemical bond strength, it showed a negative effect on SBS compared to other treatment methods, which was noticeable after the thermal cycling treatment.

Non-thermal plasma accelerates the healing process of peripheral nerve crush injury in rats.

The objective of this study was to evaluate the effect of non-thermal plasma (NTP) on the healing process of peripheral nerve crush injuries, which can occur during dental implant procedures. For this, a rat model of sciatic nerve crush injury (SNCI) was adopted. The rats were divided into three groups: non-nerve damage (non-ND), nerve damage (ND), and ND+NTP group. To evaluate the sciatic nerve (SN) function, the static sciatic index was calculated, and the muscle and SN tissues were subjected to a histologic analysis. The results showed that NTP effectively accelerated the healing process of SNCI in rats. In contrast to the ND group, which showed approximately 60% recovery in the SN function, the NTP-treated rats showed complete recovery. Histologically, the NTP treatments not only accelerated the muscle healing, but also reduced the edema-like phenotype of the damaged SN tissues. In the ND group, the SN tissues had an accumulation of CD68-positive macrophages, partially destroyed axonal fibers and myelinated Schwann cells. Conversely, in the ND+NTP group, the macrophage accumulation was reduced and an overall regeneration of the damaged axon fibers and the myelin sheath was accomplished. The results of this study indicate that NTP can be used for healing of injured peripheral nerves.

Non-thermal atmospheric pressure plasma induces epigenetic modifications that activate the expression of various cytokines and growth factors in human mesoderm-derived stem cells.

Non-thermal atmospheric pressure plasma (NTAPP) has been reported to induce wound healing, activation of immune cells, and proliferation of mesoderm-derived adult stem cells in human. However, the mechanism by which NTAPP activates these physiological effects is poorly understood. Here, we examined whole genome expression profiles of adipose tissue-derived stem cells (ASCs), the proliferation of which is induced by NTAPP. NTAPP upregulated the expression of genes for cytokine and growth factor, but downregulated genes in apoptotic pathways. When ASCs were treated with NTAPP in the presence of a nitric oxide (NO) scavenger, the expression of various cytokines and growth factors decreased, suggesting that NO is primarily responsible for the enhanced cytokine and growth factor expression induced by NTAPP. Increased histone deacetyl transferase 1 (HDAC1) and decreased acetylated histone 3 were detected in NTAPP-treated ASCs. Similarly, ASCs pre-treated with HDAC, DNA methylation, or histone methylation inhibitors had reduced expression of cytokines and growth factors after NTAPP treatment. Taken together, these results strongly suggest that NTAPP induces epigenetic modifications that activate the expression of cytokines and growth factors, explaining how NTAPP acts as an efficient tool in regenerative medicine to stimulate stem cell proliferation, to activate immune cells, and to recover wounds.

Influence of Non-Thermal Atmospheric Pressure Plasma Treatment on Shear Bond Strength between Y-TZP and Self-Adhesive Resin Cement.

The purpose of this study was to evaluate the effect of non-thermal atmospheric pressure plasma (NTP) on shear bond strength (SBS) between yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) and self-adhesive resin cement. For this study, surface energy (SE) was calculated with cube-shaped Y-TZP specimens, and SBS was measured on disc-shaped Y-TZP specimens bonded with G-CEM LinkAce or RelyX U200 resin cylinder. The Y-TZP specimens were classified into four groups according to the surface treatment as follows: Control (no surface treatment), NTP, Sb (Sandblasting), and Sb + NTP. The results showed that the SE was significantly higher in the NTP group than in the Control group (p < 0.05). For the SBS test, in non-thermocycling, the NTP group of both self-adhesive resin cements showed significantly higher SBS than the Control group (p < 0.05). However, regardless of the cement type in thermocycling, there was no significant increase in the SBS between the Control and NTP groups. Comparing the two cements, regardless of thermocycling, the NTP group of G-CEM LinkAce showed significantly higher SBS than that of RelyX U200 (p < 0.05). Our study suggests that NTP increases the SE. Furthermore, NTP increases the initial SBS, which is higher when using G-CEM LinkAce than when using RelyX U200.