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Derong Yin,1 Satoshi Komasa,1 Shigeki Yoshimine,1 Tohru Sekino,2 Joji Okazaki11Department of Removable Prosthodontics and Occlusion, Osaka Dental University, Hirakata, Osaka, Japan; 2Advanced Hard Materials, The Institute of Scientific and Industrial Research, Osaka University, Suita, Osaka, JapanPurpose: On the basis of reasonable superposition of various surface treatment methods, alkali-treated titanium with nanonetwork structures (TNS) was coated with mussel adhesive protein (MAP) and named TNS-MAP. The aims were to optimize the biological properties of TNS, endue it with new properties, and enhance its utility in clinical dental applications.Methods: TNS disks were coated with MAP and the product surface was characterized. Its osteogenic properties were determined by evaluating its effects on cell adhesion, cell proliferation, the expression of osteogenesis-related genes, and in vivo experiments.Results: The treated materials showed excellent hydrophilicity, good surface roughness, and advantages of both TNS and MAP. TNS-MAP significantly promoted initial cell attachment especially after 15 mins and 30 mins. At every time point, cell adhesion and proliferation, the detection rate of osteogenesis-related markers in the extracellular matrix, and the expression of osteogenesis-related genes were markedly superior on TNS-MAP than the control. The in vivo experiments revealed that TNS-MAP promoted new bone growth around the implants and the bone–implant interface.Conclusion: We verified through in vitro and in vivo experiments that we successfully created an effective TNS-MAP composite implant with excellent biocompatibility and advantages of both its TNS and MAP parent materials. Therefore, the new biocomposite implant material TNS-MAP may potentially serve in practical dentistry and orthopedics.Keywords: biocomposite, bone marrow mesenchymal stem cell, extracellular matrix, nanopore, polydopamine

Xing H, Komasa S, Taguchi Y, Sekino T, Okazaki J. Int J Nanomedicine. 2014;9(1): 1741–1755. The Editor-in-Chief and Publisher of International Journal of Nanomedicine wish to retract the published article. Concerns were raised of alleged image duplication observed in several figures within the article. Specifically: Figure 7A panel 10.0 M 1 week appears to be duplicated with Figure 7B panel 10.0 M 2 weeks. Figure 7A panel 5.0 M 1 week appears to be duplicated with Figure 7A panel 12.5 M 1 week. Figure 8B panel CON 4 weeks appears to be duplicated with Figure 8B panel 2.5 M 4 weeks. Despite several attempts the authors did not respond to our queries and the decision was made to retract the article. Our decision-making was informed by our policy on publishing ethics and integrity and the COPE guidelines on retraction. The retracted article will remain online to maintain the scholarly record, but it will be digitally watermarked on each page as “Retracted”. This retraction relates to this paper

Honghao Zhang,1,2 Satoshi Komasa,1 Chiho Mashimo,3 Tohru Sekino,4 Joji Okazaki1 1Department of Removable Prosthodontics and Occlusion, Osaka Dental University, Hirakata, Osaka, Japan; 2Department of Stomatology, Nanfang Hospital and College of Stomatology, Southern Medical University, Guangzhou, Guangdong, China; 3Department of Bacteriology, Osaka Dental University, Hirakata, 4The Institute of Scientific and Industrial Research, Osaka University, Suita, Osaka, Japan Purpose: Alkali-treated titanium with nanonetwork structures (TNS) possesses good osteogenic activity; however, the resistance of this material to bacterial contamination remains inadequate. As such, TNS implants are prone to postoperative infection. In this work, we attempted to alter the biological properties of TNS by treatment with short-duration high-intensity ultraviolet (UV) irradiation.Methods: TNS discs were treated with UV light (wavelength =254 nm, strength =100 mW/cm2) for 15 minutes using a UV-irradiation machine. We carried out a surface characterization and evaluated the discs for bacterial film formation, protein adsorption, and osteogenic features.Results: The superhydrophilicity and surface hydrocarbon elimination exhibited by the treated material (UV-treated titanium with a nanonetwork structure [UV-TNS]) revealed that this treatment effectively changed the surface characteristics of TNS. Notably, UV-TNS also showed reduced colonization by Actinomyces oris during an initial attachment period and inhibition of biofilm formation for up to 6 hours. Moreover, compared to conventional TNS, UV-TNS showed superior osteogenic activity as indicated by increased levels of adhesion, proliferation, alkaline phosphatase activity, osteogenic factor production, and osteogenesis-related gene expression by rat bone marrow mesenchymal stem cells (rBMMSCs). This inverse relationship between bacterial attachment and cell adhesion could be due to the presence of electron–hole pairs induced by high-intensity UV treatment.Conclusion: We suggest that simple UV treatment has great clinical potential for TNS implants, as it promotes the osseointegration of the TNS while reducing bacterial contamination, and can be conducted chair-side immediately prior to implantation. Keywords: implant, nanonetwork, postoperative infection, UV treatment, superhydrophilicity, osteointegration

Yingmin Su,1 Satoshi Komasa,1 Peiqi Li,2 Mariko Nishizaki,1 Luyuan Chen,1 Chisato Terada,1 Shigeki Yoshimine,1 Hiroshi Nishizaki,1 Joji Okazaki1 1Department of Removable Prosthodontics and Occlusion, 2Department of Oral Implantology, Osaka Dental University, Hirakata, Osaka, Japan Abstract: Both bioactive ion chemistry and nanoscale surface modifications are beneficial for enhanced osseointegration of endosseous implants. In this study, a facile synthesis approach to the incorporation of bioactive Ca2+ ions into the interlayers of nanoporous structures (Ca-nano) formed on a Ti6Al4V alloy surface was developed by sequential chemical and heat treatments. Samples with a machined surface and an Na+ ion-incorporated nanoporous surface (Na-nano) fabricated by concentrated alkali and heat treatment were used in parallel for comparison. The bone response was investigated by microcomputed tomography assessment, sequential fluorescent labeling analysis, and histological and histomorphometric evaluation after 8 weeks of implantation in rat femurs. No significant differences were found in the nanotopography, surface roughness, or crystalline properties of the Ca-nano and Na-nano surfaces. Bone–implant contact was better in the Ca-nano and Na-nano implants than in the machined implant. The Ca-nano implant was superior to the Na-nano implant in terms of enhancing the volume of new bone formation. The bone formation activity consistently increased for the Ca-nano implant but ceased for the Na-nano implant in the late healing stage. These results suggest that Ca-nano implants have promising potential for application in dentistry and orthopedics. Keywords: surface modification, nanotopography, bioactive ion, osteoinduction, osseointegration

Bone tissue engineering is a technique that simulates the bone tissue microenvironment by utilizing cells, tissue scaffolds, and growth factors. The collagen hydrogel is a three-dimensional network bionic material that has properties and structures comparable to those of the extracellular matrix (ECM), making it an ideal scaffold and drug delivery system for tissue engineering. The clinical applications of this material are restricted due to its low mechanical strength. In this investigation, a collagen-based gel (atelocollagen/glycerol/pullulan [Col/Gly/Pul] gel) that is moldable and injectable with high adhesive qualities was created by employing a straightforward technique that involved the introduction of Gly and Pul. This study aimed to characterize the internal morphology and chemical composition of the Col/Gly/Pul gel, as well as to verify its osteogenic properties through in vivo and in vitro experiments. When compared to a standard pure Col hydrogel, this material is more adaptable to the complexity of the local environment of bone defects and the apposition of irregularly shaped flaws due to its greater mechanical strength, injectability, and moldability. Overall, the Col/Gly/Pul gel is an implant that shows great potential for the treatment of complex bone defects and the enhancement of bone regeneration.

In recent years, with the advent of a super-aged society, lifelong dental care has gained increasing emphasis, and implant therapy for patients with an edentulous jaw has become a significant option. However, for implant therapy to be suitable for elderly patients with reduced regenerative and immunological capabilities, higher osteoconductive and antimicrobial properties are required on the implant surfaces. Silicon nitride, a non-oxide ceramic known for its excellent mechanical properties and biocompatibility, has demonstrated high potential for inducing hard tissue differentiation and exhibiting antibacterial properties. In this study, silicon nitride was deposited on pure titanium metal surfaces and evaluated for its biocompatibility and antibacterial properties. The findings indicate that silicon nitride improves the hydrophilicity of the material surface, enhancing the initial adhesion of rat bone marrow cells and promoting hard tissue differentiation. Additionally, the antibacterial properties were assessed using Staphylococcus aureus, revealing that the silicon nitride-coated surfaces exhibited significant antibacterial activity. Importantly, no cytotoxicity was observed, suggesting that silicon nitride-coated titanium could serve as a novel implant material.

In a previous study, we successfully coated hydroxyapatite (HAp) onto titanium (Ti) plates using the erbium-doped yttrium aluminum garnet pulsed-laser deposition (Er:YAG-PLD) method. In this study, we performed further experiments to validate the in vitro osteogenic properties, macrophage polarization, and in vivo osseointegration activity of HAp-coated Ti (HAp-Ti) plates and screws. Briefly, we coated a HAp film onto the surfaces of Ti plates and screws via Er:YAG-PLD. The surface morphological, elemental, and crystallographic analyses confirmed the successful surface coating. The macrophage polarization and osteogenic induction were evaluated in macrophages and rat bone marrow mesenchymal stem cells, and the in vivo osteogenic properties were studied. The results showed that needle-shaped nano-HAp promoted the early expression of osteogenic and immunogenic genes in the macrophages and induced excellent M2 polarization properties. The calcium deposition and osteocalcin production were significantly higher in the HAp-Ti than in the uncoated Ti. The implantation into rat femurs revealed that the HAp-coated materials had superior osteoinductive and osseointegration activities compared with the Ti, as assessed by microcomputed tomography and histology. Thus, HAp film on sandblasted Ti plates and screws via Er:YAG-PLD enhances hard-tissue differentiation, macrophage polarization, and new bone formation in tissues surrounding implants both in vitro and in vivo.

In this study, we applied argon plasma treatment to titanium surfaces with nanostructures deposited by concentrated alkali treatment and investigated the effects on the surface of the material and the tissue surrounding an implant site. The results showed that the treatment with argon plasma removed carbon contaminants and increased the surface energy of the material while the nanoscale network structure deposited on the titanium surface remained in place. Reactive oxygen species reduced the oxidative stress of bone marrow cells on the treated titanium surface, creating a favorable environment for cell proliferation. Good results were observed in vitro evaluations using rat bone marrow cells. The group treated with argon plasma exhibited the highest apatite formation in experiments using simulated body fluids. The results of in vivo evaluation using rat femurs revealed that the treatment improved the amount of new bone formation around an implant. Thus, the results demonstrate that argon plasma treatment enhances the ability of nanostructured titanium surfaces to induce hard tissue differentiation and supports new bone formation around an implant site.

Pure titanium is used in dental implants owing to its excellent biocompatibility and physical properties. However, the aging of the material during storage is detrimental to the long-term stability of the implant after implantation. Therefore, in this study, we attempted to improve the surface properties and circumvent the negative effects of material aging on titanium implants by using a portable handheld nonthermal plasma device capable of piezoelectric direct discharge to treat pure titanium discs with nitrogen gas. We evaluated the osteogenic properties of the treated samples by surface morphology and elemental analyses, as well as in vitro and in vivo experiments. The results showed that nonthermal atmospheric-pressure nitrogen plasma can improve the hydrophilicity of pure titanium without damaging its surface morphology while introducing nitrogen-containing functional groups, thereby promoting cell attachment, proliferation, and osseointegration to some extent. Therefore, nitrogen plasma treatment may be a promising method for the rapid surface treatment of titanium implants.

The surface of titanium (Ti) dental implants must be modified to improve their applicability, owing to the biological inertness of Ti. This study aims to use sandblasting as a pretreatment method and prepare a hydroxyapatite (HA) coating on Ti to improve its biocompatibility and induce bone bonding and osteogenesis. In this paper, sandblasted Ti discs were coated with α-tricalcium phosphate (α-TCP) via Er:YAG pulsed laser deposition (Er:YAG-PLD). An HA coating was then obtained via the hydrothermal treatment of the discs at 90 °C for 10 h. The surface characteristics of the samples were evaluated by SEM, SPM, XPS, XRD, FTIR, and tensile tests. Rat bone marrow mesenchymal stem cells were seeded on the HA-coated discs to determine cellular responses in vitro. The surface characterization results indicated the successful transformation of the HA coating with a nanorod-like morphology, and its surface roughness increased. In vitro experiments revealed increased cell attachment on the HA-coated discs, as did the cell morphology of fluorescence staining and SEM analysis; in contrast, there was no increase in cell proliferation. This study confirms that Er:YAG-PLD could be used as an implant surface-modification technique to prepare HA coatings with a nanorod-like morphology on Ti discs.

Standard zirconia implants used in restoration still present problems related to inertness and long-term stability. Various physicochemical approaches have been used to modify the implant surfaces to improve early and late bone-to-implant integration; however, no ideal surface modification has been reported. This study used pulsed laser deposition to deposit a fluorinated hydroxyapatite (FHA) film on a zirconia implant to create a biologically active surface. The film prepared was uniform, dense, and crack-free, and exhibited granular surface droplets; it also presented excellent mechanical strength and favorable biological behavior. The FHA-coated implant was implanted on the femur of Sprague-Dawley rats, and various tests and analyses were performed. Results show that the in vitro initial cell activity on the FHA-coated samples was enhanced. In addition, higher alkaline phosphatase activity and cell mineralization were detected in cells cultured on the FHA-coated groups. Further, the newly formed bone volume of the FHA-coated group was higher than that of the bare micro-adjusted composite nano-zirconia (NANOZR) group. Therefore, the FHA film facilitated osseointegration and may improve the long-term survival rates of dental implants, and could become part of a new treatment technology for implant surfaces, promoting further optimization of NANOZR implant materials.

Polyetheretherketone (PEEK) is a potential substitute for conventional metallic biomedical implants owing to its superior mechanical and chemical properties, as well as biocompatibility. However, its inherent bio-inertness and poor osseointegration limit its use in clinical applications. Herein, thin titanium films were deposited on the PEEK substrate by plasma sputtering, and porous nanonetwork structures were incorporated on the PEEK surface by alkali treatment (PEEK-TNS). Changes in the physical and chemical characteristics of the PEEK surface were analyzed to establish the interactions with cell behaviors. The osteoimmunomodulatory properties were evaluated using macrophage cells and osteoblast lineage cells. The functionalized nanostructured surface of PEEK-TNS effectively promoted initial cell adhesion and proliferation, suppressed inflammatory responses, and induced macrophages to anti-inflammatory M2 polarization. Compared with PEEK, PEEK-TNS provided a more beneficial osteoimmune environment, including increased levels of osteogenic, angiogenic, and fibrogenic gene expression, and balanced osteoclast activities. Furthermore, the crosstalk between macrophages and osteoblast cells showed that PEEK-TNS could provide favorable osteoimmunodulatory environment for bone regeneration. PEEK-TNS exhibited high osteogenic activity, as indicated by alkaline phosphatase activity, osteogenic factor production, and the osteogenesis/osteoclastogenesis-related gene expression of osteoblasts. The study establishes that the fabrication of titanate nanonetwork structures on PEEK surfaces could extract an adequate immune response and favorable osteogenesis for functional bone regeneration. Furthermore, it indicates the potential of PEEK-TNS in implant applications.

There are treatments available for enamel demineralization or acid erosion, but they have limitations. We aimed to manufacture a device that could directly form a hydroxyapatite (HAp) film coating on the enamel with a chairside erbium-doped yttrium aluminum garnet (Er:YAG) laser using the pulsed laser deposition (PLD) method for repairing enamel defects. We used decalcified bovine enamel specimens and compacted α-tricalcium phosphate (α-TCP) as targets of Er:YAG-PLD. With irradiation, an α-TCP coating layer was immediately deposited on the specimen surface. The morphological, mechanical, and chemical characteristics of the coatings were evaluated using scanning electron microscopy (SEM), scanning probe microscopy (SPM), X-ray diffractometry (XRD), and a micro-Vickers hardness tester. Wear resistance, cell attachment of the HAp coatings, and temperature changes during the Er:YAG-PLD procedure were also observed. SEM demonstrated that the α-TCP powder turned into microparticles by irradiation. XRD peaks revealed that the coatings were almost hydrolyzed into HAp within 2 days. Micro-Vickers hardness indicated that the hardness lost by decalcification was almost recovered by the coatings. The results suggest that the Er:YAG-PLD technique is useful for repairing enamel defects and has great potential for future clinical applications.

Oral dysfunction due to peri-implantitis and shortened life of implants has become a major concern. Self-care and removal of oral biofilms by professional mechanical tooth cleaning (PMTC) are indispensable for its prevention. However, if the surface roughness of the implant is increased, it may result in the adhesion of biofilm in the oral cavity. Therefore, the PMTC method can serve for long-term implant management. Calcium carbonate (CaCO 3 ) has been used as a cleaning method for implant surfaces; however, there is concern that the implant surface roughness could increase due to particle collision. Therefore, in this study, to establish a blasting cleaning method that does not adversely affect the implant surface, a new blasting cleaning method using agar particles was devised and its practical application examined. When the simulated stains were blasted with white alumina (WA) abrasive grains and CaCO 3 particles, the simulated stains were almost removed, the surface roughness changed to a satin-finished surface-which was thought to be due to fine scratches-and the surface roughness increased. Most of the simulated stains were removed on the surface of the sample blasted with glycine particles and agar particles. Conversely, the gloss of the sample surface was maintained after cleaning, and the increase in surface roughness was slight.

The immunomodulatory antibacterial activity and osteoimmunomodulatory properties of implantable biomaterials significantly influence bone regeneration. Various types of ultraviolet (UV) instrument are currently in use to greatly enhance the antibacterial activity and osteoconductive capability of titanium, it remains unclear how UV treatment modulates immune response. Compared to traditional UV treatment, the combination of low-dose ozone with UV irradiation is considered a new option to give benefits to surface modification and reduce the drawbacks of UV and ozone individually. Herein, the aim of this study was to elucidate the immune-modulatory properties of macrophages on UV/ozone-irradiated titanium that serve as defense against S. aureus and the crosstalk between immune cells and osteoblasts. Three different cell and bacteria co-culture systems were developed in order to investigate the race between host cells and bacteria to occupy the surface. In vitro immunological experiments indicated that UV/ozone irradiation significantly enhanced the phagocytic and bactericidal activity of macrophages against S. aureus. Further, in vitro and in vivo studies evidenced the favorable osteoimmune environment for osteogenic differentiation and bone formation. This research suggests vital therapeutic potential of UV/ozone irradiation for preventing the biomaterial-associated infections and achieving favorable bone formation simultaneously., (Copyright © 2021 Elsevier B.V. All rights reserved.)

In this paper, we suggest that the atmospheric pressure plasma treatment of pure titanium metal may be useful for improving the ability of rat bone marrow cells (RBMCs) to induce hard tissue differentiation. Previous studies have reported that the use of argon gas induces a higher degree of hard tissue formation. Therefore, this study compares the effects of plasma treatment with argon gas on the initial adhesion ability and hard tissue differentiation-inducing ability of RBMCs. A commercially available titanium metal plate was used as the experimental material. A plate polished using water-resistant abrasive paper #1500 was used as the control, and a plate irradiated with argon mixed with atmospheric pressure plasma was used as the experimental plate. No structural change was observed on the surface of the titanium metal plate in the scanning electron microscopy results, and no change in the surface roughness was observed via scanning probe microscopy. X-ray photoelectron spectroscopy showed a decrease in the carbon peak and the formation of hydroxide in the experimental group. In the distilled water drop test, a significant decrease in the contact angle was observed for the experimental group, and the results indicated superhydrophilicity. Furthermore, the bovine serum albumin adsorption, initial adhesion of RBMCs, alkaline phosphatase activity, calcium deposition, and genetic marker expression of rat bone marrow cells were higher in the experimental group than those in the control group at all time points. Rat distal femur model are used as in vivo model. Additionally, microcomputed tomography analysis showed significantly higher results for the experimental group, indicating a large amount of the formed hard tissue. Histopathological evaluation also confirmed the presence of a prominent newly formed bone seen in the images of the experimental group. These results indicate that the atmospheric pressure plasma treatment with argon gas imparts superhydrophilicity, without changing the properties of the pure titanium plate surface. It was also clarified that it affects the initial adhesion of bone marrow cells and the induction of hard tissue differentiation.

Early osseointegration is important to achieve initial stability after implant placement. We have previously reported that atmospheric-pressure plasma treatment confers superhydrophilicity to titanium. Herein, we examined the effects of titanium implant material, which was conferred superhydrophilicity by atmospheric-pressure plasma treatment, on the surrounding tissue in rat femur. Control and experimental groups included untreated screws and those irradiated with atmospheric-pressure plasma using piezobrush, respectively. The femurs of 8-week-old male Sprague-Dawley rats were used for in vivo experiments. Various data prepared from the Micro-CT analysis showed results showing that more new bone was formed in the test group than in the control group. Similar results were shown in histological analysis. Thus, titanium screw, treated with atmospheric-pressure plasma, could induce high hard tissue differentiation even at the in vivo level. This method may be useful to achieve initial stability after implant placement.

Primary stability and osseointegration are major challenges in dental implant treatments, where the material surface properties and wettability are critical in the early formation of hard tissue around the implant. In this study, a quartz crystal microbalance (QCM) was used to measure the nanogram level amount of protein and bone marrow cells adhered to the surfaces of titanium (Ti) surface in real time. The effects of ultraviolet (UV) and atmospheric-pressure plasma treatment to impart surface hydrophilicity to the implant surface were evaluated. The surface treatment methods resulted in a marked decrease in the surface carbon (C) content and increase in the oxygen (O) content, along with super hydrophilicity. The results of QCM measurements showed that adhesion of both adhesive proteins and bone marrow cells was enhanced after surface treatment. Although both methods produced implants with good osseointegration behavior and less reactive oxidative species, the samples treated with atmospheric pressure plasma showed the best overall performance and are recommended for clinical use. It was verified that QCM is an effective method for analyzing the initial adhesion process on dental implants.

The Bio-C Sealer is a recently developed high-plasticity, calcium-silicate-based, ready-to-use material. In the present study, chemical elements of the materials were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The biocompatibility of the Bio-C Sealer was investigated using cytotoxicity tests and histological responses in the roots of dogs' teeth. XRD, SEM, and FTIR produced hydrated calcium silicate in the presence of water molecules. In addition, FTIR showed the formation of calcium hydroxide and polyethylene glycol, a dispersing agent. The 1:4 dilutions of Bio-C Sealer presented weaker cytotoxicity than the Calcipex II in an in vitro system using the V-79 cell line. After 90 d, the periradicular tissue response of beagle dog roots was histologically evaluated. Absence of periradicular inflammation was reported in 17 of the 18 roots assessed with the Bio-C Sealer, whereas mature vertical periodontal ligament fibers were observed in the apical root ends filled with the Bio-C Sealer. Based on these results and previous investigations, the Bio-C Sealer is recommended as an effective root-end filling material. These results are relevant for clinicians considering the use of Bio-C Sealer for treating their patients.

Zirconia ceramics such as ceria-stabilized zirconia/alumina nanocomposites (nano-ZR) are applied as implant materials due to their excellent mechanical properties. However, surface treatment is required to obtain sufficient biocompatibility. In the present study, we explored the material surface functionalization and assessed the initial adhesion of rat bone marrow mesenchymal stem cells, their osteogenic differentiation, and production of hard tissue, on plasma-treated alkali-modified nano-ZR. Superhydrophilicity was observed on the plasma-treated surface of alkali-treated nano-ZR along with hydroxide formation and reduced surface carbon. A decreased contact angle was also observed as nano-ZR attained an appropriate wettability index. Treated samples showed higher in vitro bovine serum albumin (BSA) adsorption, initial adhesion of bone marrow and endothelial vascular cells, high alkaline phosphatase activity, and increased expression of bone differentiation-related factors. Furthermore, the in vivo performance of treated nano-ZR was evaluated by implantation in the femur of male Sprague-Dawley rats. The results showed that the amount of bone formed after the plasma treatment of alkali-modified nano-ZR was higher than that of untreated nano-ZR. Thus, induction of superhydrophilicity in nano-ZR via atmospheric pressure plasma treatment affects bone marrow and vascular cell adhesion and promotes bone formation without altering other surface properties.

Nanostructured zirconia/alumina composite (NANOZR) has been explored as a suitable material for fabricating implants for patients with metal allergy. In this study, we examined the effect of UV treatment on the NANOZR surface. The experimental group was UV-treated NANOZR and the control group was untreated NANOZR. Observation of the surface of the UV-treated materials revealed no mechanical or structural change; however, the carbon content on the material surface was reduced, and the material surface displayed superhydrophilicity. Further, the effects of the UV-induced superhydrophilic properties of NANOZR plates on the adhesion behavior of various cells were investigated. Treatment of the NANOZR surface was found to facilitate protein adsorption onto it. An in vitro evaluation using rat bone marrow cells, human vascular endothelial cells, and rat periodontal ligament cells revealed high levels of adhesion in the experimental group. In addition, it was clarified that the NANOZR surface forms active oxygen and suppresses the generation of oxidative stress. Overall, the study results suggested that UV-treated NANOZR is useful as a new ceramic implant material.

Alkali-treated titanate layer with nanonetwork structures (TNS) is a promising surface for improving osseointegration capacity in implants. Nevertheless, there is a risk of device failure as a result of insufficient resistance to biofilm contamination. This study tested whether treatment using a handheld non-thermal plasma device could efficiently eliminate biofilm contamination without destroying the surface nanostructure while re-establishing a surface that promoted new bone generation. TNS specimens were treated by a piezoelectric direct discharge (PDD) plasma generator. The effect of decontamination was performed utilizing Staphylococcus aureus . The evaluation of initial cell attachment with adhesion images, alkaline phosphatase activity, extracellular matrix mineralization, and expression of genes related to osteogenesis was performed using rat bone marrow mesenchymal stem cells, and the bone response were evaluated in vivo using a rat femur model. Nanotopography and surface roughness did not significantly differ before and after plasma treatments. Cell and bone formation activity were improved by TNS plasma treatment. Furthermore, plasma treatment effectively eliminated biofilm contamination from the surface. These results suggested that this plasma treatment may be a promising approach for the treatment of nanomaterials immediately before implantation and a therapeutic strategy for peri-implantitis.

Contamination of implants is inevitable during different steps of production as well as during the clinical use. We devised a new implant cleaning strategy to restore the bioactivities on dental implant surfaces. We evaluated the efficiency of the Finevo cleaning system, and Ultraviolet and Plasma treatments to decontaminate hydrocarbon-contaminated titanium disks. The surfaces of the contaminated titanium disks cleaned using the Finevo cleaning system were similar to those of the uncontaminated titanium disks in scanning electron microscopy and X-ray photoelectron spectroscopy analysis, but no obvious change in the roughness was observed in the scanning probe microscopy analysis. The rat bone marrow mesenchymal stem cells (rBMMSCs) cultured on the treated titanium disks attached to and covered the surfaces of disks cleaned with the Finevo cleaning system. The alkaline phosphatase activity, calcium deposition, and osteogenesis-related gene expression in rBMMSCs on disks cleaned using the Finevo cleaning system were higher compared to those in the ultraviolet and plasma treatments, displaying better cell functionality. Thus, the Finevo cleaning system can enhance the attachment, differentiation, and mineralization of rBMMSCs on treated titanium disk surfaces. This research provides a new strategy for cleaning the surface of contaminated titanium dental implants and for restoration of their biological functions.

Advancing bone implant engineering offers the opportunity to overcome crucial medical challenges and improve clinical outcomes. Although the establishment of a functional vascular network is crucial for bone development, its regeneration inside bone tissue has only received limited attention to date. Herein, we utilize siRNA-decorated particles to engineer a hierarchical nanostructured coating on clinically used titanium implants for the synergistic regeneration of skeletal and vascular tissues. Specifically, an siRNA was designed to target the regulation of cathepsin K and conjugated on nanoparticles. The functionalized nanoparticles were assembled onto the bone implant to form a hierarchical nanostructured coating. By regulating mRNA transcription, the coating significantly promotes cell viability and growth factor release related to vascularization. Moreover, microchip-based experiments demonstrate that the nanostructured coating facilitates macrophage-induced synergy in up-regulation of at least seven bone and vascular growth factors. Ovariectomized rat and comprehensive beagle dog models highlight that this siRNA-integrated nanostructured coating possesses all the key traits of a clinically promising candidate to address the myriad of challenges associated with bone regeneration., Competing Interests: Declaration of competing interest The authors confirm that there are no conflicts of interest., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

This study describes the production of a new material composed of pure titanium (Ti) metal with a crystallized nanostructure and investigated whether heat treatment and ultraviolet (UV) irradiation improved its biocompatibility and antibacterial properties. We compared the performance of UV-irradiated and non-irradiated Ti nanosheets (TNS) formed by dark alkaline treatment and heating at 600 °C with that of untreated pure Ti nanostructure (positive control). In vitro and in vivo experiments to assess biocompatibility and effects on cell behavior were performed using human umbilical vein endothelial cells and rat bone marrow cells. The material surface was characterized by X-ray photoelectron spectroscopy (XPS). The antibacterial properties of the irradiated material were evaluated using Staphylococcus aureus , a common pathogenic bacterium. The UV-irradiated TNS exhibited high angiogenic capacity and promoted cell adherence and differentiation relative to the control. Further, surface analysis via XPS revealed a lower C peak for the UV-treated material, indicating a reduced amount of dirt on the material surface. Moreover, UV irradiation decreased the viability of S. aureus on the material surface by stimulating reactive oxygen species production. The biocompatibility and antibacterial properties of the TNS were improved by UV irradiation. Thus, TNS may serve as a useful material for fabrication of dental implants.

Alkali-treated titanium (Ti) with a porous, homogeneous, and uniform nanonetwork structure (TNS) that enables establishment of a more rapid and firmer osteointegration than titanium has recently been reported. However, the mechanisms underlying the enhanced osteogenic activity on TNS remains to be elucidated. This study aimed to evaluate the surface physicochemical properties of Ti and TNS, and investigate osteoinduction and osteointegration in vivo. Surface characteristics were evaluated using scanning electron microscopy (SEM), scanning probe microscopy (SPM), and X-ray photoelectron spectrometry (XPS), and the surface electrostatic force of TNS was determined using solid zeta potential. This study also evaluated the adsorption of bovine serum albumin (BSA) and human plasma fibronectin (HFN) on Ti and TNS surfaces using quartz crystal microbalance (QCM) sensors, and apatite formation on Ti and TNS surfaces was examined using a simulated body fluid (SBF) test. Compared with Ti, the newly developed TNS enhanced BSA and HFN absorbance capacity and promoted apatite formation. Furthermore, TNS held less negative charge than Ti. Notably, sequential fluorescence labeling and microcomputed tomography assessment indicated that TNS screws implanted into rat femurs exhibited remarkably enhanced osteointegration compared with Ti screws. These results indicate that alkali-treated titanium implant with a nanonetwork structure has considerable potential for future clinical applications in dentistry and orthopedics.

Ingredients and surface modification methods are being continually developed to improve osseointegration of dental implants and reduce healing times. In this study, we demonstrate in vitro that, by applying concentrated alkali treatment to NANOZR with strong bending strength and fracture toughness, a significant improvement in the bone differentiation of rat bone marrow cells can be achieved. We investigated the influence of materials modified with this treatment in vivo, on implanted surrounding tissues using polychrome sequential fluorescent labeling and micro-computer tomography scanning. NANOZR implant screws in the alkali-treated group and the untreated group were evaluated after implantation in the femur of Sprague⁻Dawley male rats, indicating that the amount of new bone in the alkali-modified NANOZR was higher than that of unmodified NANOZR. Alkali-modified NANOZR implants proved to be useful for the creation of new implant materials.

The interactions between implants and host tissues depend on several factors. In particular, a growing body of evidence has demonstrated that the surface texture of an implant influences the response of the surrounding cells. The purpose of this study is to develop new implant materials aiming at the regeneration of periodontal tissues as well as hard tissues by coating nano-modified titanium with amelogenin, which is one of the main proteins contained in Emdogain ® . We confirmed by quartz crystal microbalance evaluation that amelogenin is easy to adsorb onto the nano-modified titanium surface as a coating. Scanning electron microscopy, scanning probe microscopy, X-ray photoelectron spectroscopy, and Fourier-transform infrared spectroscopy analyses confirmed that amelogenin coated the nano-modified titanium surface following alkali-treatment. In vitro evaluation using rat bone marrow and periodontal ligament cells revealed that the initial adhesion of both cell types and the induction of hard tissue differentiation such as cementum were improved by amelogenin coating. Additionally, the formation of new bone in implanted surrounding tissues was observed in in vivo evaluation using rat femurs. Together, these results suggest that this material may serve as a new implant material with the potential to play a major role in the advancement of clinical dentistry.

To enhance biocompatibility, osteogenesis, and osseointegration, we coated titanium implants, by krypton fluoride (KrF) pulsed laser deposition, with a thin film of fluoridated hydroxyapatite (FHA). Coating was confirmed by scanning electron microscopy (SEM) and scanning probe microscopy (SPM), while physicochemical properties were evaluated by attenuated reflectance Fourier transform infrared spectroscopy (ATR-FTIR). Calcium deposition, osteocalcin production, and expression of osteoblast genes were significantly higher in rat bone marrow mesenchymal stem cells seeded on FHA-coated titanium than in cells seeded on uncoated titanium. Implantation into rat femurs also showed that the FHA-coated material had superior osteoinductive and osseointegration activity in comparison with that of traditional implants, as assessed by microcomputed tomography and histology. Thus, titanium coated with FHA holds promise as a dental implant material., Competing Interests: The authors declare no conflict of interest.

This study developed a drug-loadable hydrogel system with high plasticity and favorable biological properties to enhance oral bone tissue regeneration. Hydrogels of different calcium alginate concentrations were prepared. Their swelling ratio, degradation time, and bovine serum albumin (BSA) release rate were measured. Human periodontal ligament cells (hPDLCs) and bone marrow stromal cells (BMSCs) were cultured with both calcium alginate hydrogels and polylactic acid (PLA), and then we examined the proliferation of cells. Inflammatory-related factor gene expressions of hPDLCs and osteogenesis-related gene expressions of BMSCs were observed. Materials were implanted into the subcutaneous tissue of rabbits to determine the biosecurity properties of the materials. The materials were also implanted in mandibular bone defects and then scanned using micro-CT. The calcium alginate hydrogels caused less inflammation than the PLA. The number of mineralized nodules and the expression of osteoblast-related genes were significantly higher in the hydrogel group compared with the control group. When the materials were implanted in subcutaneous tissue, materials showed favorable biocompatibility. The calcium alginate hydrogels had superior osteoinductive bone ability to the PLA. The drug-loadable calcium alginate hydrogel system is a potential bone defect reparation material for clinical dental application.

In recent years, zirconia has been a recognized implant material in clinical dentistry. In the present study, we investigated the performance of an alkali-modified ceria-stabilized tetragonal ZrO₂ polycrystalline ceramic-based nanostructured zirconia/alumina composite (NANOZR) implant by assessing surface morphology and composition, wettability, bovine serum albumin adsorption rate, rat bone marrow (RBM) cell attachment, and capacity for inducing bone differentiation. NANOZR surfaces without and with alkali treatment served as the control and test groups, respectively. RBM cells were seeded in a microplate with the implant and cultured in osteogenic differentiation medium, and their differentiation was evaluated by measuring alkaline phosphatase (ALP) activity, osteocalcin (OCN) production, calcium deposition, and osteogenic gene expression. The alkali-treated NANOZR surface increased ALP activity, OCN production, calcium deposition, and osteogenesis-related gene expression in attached RBM cells. These data suggest that alkali treatment enhances the osteogenesis-inducing capacity of NANOZR implants and may therefore improve their biointegration into alveolar bone.

Here, we present the complete genome sequence of Actinomyces naeslundii strain ATCC 27039, isolated from an abdominal wound abscess. This strain is genetically transformable and will thus provide valuable information related to its crucial role in oral multispecies biofilm development., (Copyright © 2016 Mashimo et al.)

In order to optimize the creation of a nanostructured surface on Ti6Al4V titanium alloy, an alkali treatment was performed using a 10-M NaOH solution at various temperatures (30, 40, 50, and 60°C) so as to determine the optimal temperature. This was combined with subsequent heat treatments (200, 400, 600, and 800°C) in air. The effects of different temperatures for the latter treatments on the nanostructure surface and the initial cell adhesion were evaluated, and the optimal temperature of the alkali solution was found to be 30°C. Further, the nanotopography, surface chemistry, and surface roughness of the nanoporous structure were retained after heat treatments performed at 200, 400, and 600°C, and only the phase structure was altered. The amorphous sodium titanate phase, the content of which increased with increased heat-treatment temperature, may have played a role in promoting cell adhesion on the nanoporous surface. However, heat treatment at 800°C did not enhance the cell-surface attachment. Rather, the nanostructure degraded significantly with the reappearance of Al and V., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Background: Titanium (Ti) dental implants have been widely used for prosthetic reconstruction of dentition. Unfortunately, peri-implantitis can result in failure of dental implant osseointegration. Lipopolysaccharide (LPS) acts as a chronic inflammatory stimulus and maintains peri-implant inflammation, worsening the prognosis for implant osseointegration. The purpose of this study is to determine the effects of 10 M NaOH-modified Ti surface with nanonetwork structure on the proliferation and osteogenic differentiation of rat bone marrow mesenchymal stem cells (BMMSCs) in the context of Porphyromonas gingivalis LPS exposure., Methods: Titanium disks treated with 10 M NaOH solution and control were incubated with BMMSCs and exposed to P. gingivalis LPS (0, 0.1, or 1 μg/mL). The effects of the modified nanonetwork structure on osteogenic differentiation of rat BMMSCs were evaluated in the context of different concentrations of P. gingivalis LPS exposure., Results: Rat BMMSCs on the 10 M NaOH-modified Ti surface with nanonetwork structure had higher levels of osteogenesis-related gene expression and significantly greater cell proliferation, alkaline phosphatase activity, and extracellular matrix deposition and mineralization than cells on the untreated Ti surfaces, in all the groups with different doses of P. gingivalis LPS exposure., Conclusion: The 10 M NaOH-modified Ti surface with nanonetwork structure has better endotoxin tolerance under P. gingivalis LPS exposure than the non-modified surface.