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Made available in DSpace on 2022-05-01T10:19:03Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Implant-related infections at the early healing period are considered one of the main risk factors in implant failure. Designing coatings that control bacterial adhesion and have cell stimulatory behavior remains a challenging strategy for dental implants. Here, we used plasma electrolytic oxidation (PEO) to produce antimicrobial coatings on commercially pure titanium (cpTi) using bioactive elements (calcium and phosphorus) and different copper (Cu) sources: copper acetate (CuAc), copper sulfate (CuS), and copper oxide (CuO); coatings containing only Ca and P (CaP) served as controls. Cu sources drove differential physical and chemical surface features of PEO coatings, resulting in tailorable release kinetics with a sustained Cu ion release over 10 weeks. The antibacterial effects of Cu-containing coatings were roughness-dependent. CuAc coating exhibited optimal properties in terms of its hydrophilicity, pores density, and limited surface roughness, which provided the most robust antibacterial activity combined with appropriate responses of human primary stem cells and angiogenic cells. Our data indicate that Cu source selection largely determines the functionality of Cu-containing PEO coatings regarding their antibacterial efficacy and cytocompatibility. Department of Prosthodontics and Periodontology Piracicaba Dental School University of Campinas (UNICAMP) Faculdade de Ciências Odontológicas (FCO) Dental Research Division Guarulhos University Laboratory of Technological Plasmas Institute of Science and Technology São Paulo State University (UNESP) Regenerative Biomaterials Dentistry Radboudumc Laboratory of Technological Plasmas Institute of Science and Technology São Paulo State University (UNESP) CAPES: 001 FAPESP: 2017/01320-0 FAPESP: 2018/14117-0 CNPq: 304853/2018-60

Made available in DSpace on 2020-12-12T02:36:37Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-03-04 Polymicrobial infections are one of the most common reasons for inflammation of surrounding tissues and failure of implanted biomaterials. Because microorganism adhesion is the first step for biofilm formation, physical-chemical modifications of biomaterials have been proposed to reduce the initial microbial attachment. Thus, the use of superhydrophobic coatings has emerged because of their anti-biofilm properties. However, these coatings on the titanium (Ti) surface have been developed mainly by dual-step surface modification techniques and have not been tested using polymicrobial biofilms. Therefore, we developed a one-step superhydrophobic coating on the Ti surface by using a low-pressure plasma technology to create a biocompatible coating that reduces polymicrobial biofilm adhesion and formation. The superhydrophobic coating on Ti was created by the glow discharge plasma using Ar, O2, and hexamethyldisiloxane gases, and after full physical, chemical, and biological characterizations, we evaluated its properties regarding oral biofilm inhibition. The newly developed coating presented an increased surface roughness and, consequently, superhydrophobicity (contact angle over 150°) and enhanced corrosion resistance (p < 0.05) of the Ti surface. Furthermore, proteomic analysis showed a unique pattern of protein adsorption on the superhydrophobic coating without drastically changing the biologic processes mediated by proteins. Additionally, superhydrophobic treatment did not present a cytotoxic effect on fibroblasts or reduction of proliferation; however, it significantly reduced (≈8-fold change) polymicrobial adhesion (bacterial and fungal) and biofilm formation in vitro. Interestingly, superhydrophobic coating shifted the microbiological profile of biofilms formed in situ in the oral cavity, reducing by up to ≈7 fold pathogens associated with the peri-implant disease. Thus, this new superhydrophobic coating developed by a one-step glow discharge plasma technique is a promising biocompatible strategy to drastically reduce microbial adhesion and biofilm formation on Ti-based biomedical implants. Department of Prosthodontics and Periodontology Piracicaba Dental School University of Campinas (UNICAMP), 901 Limeira Avenue Department of Oral Health and Diagnostic Sciences University of Connecticut Health Center, 263 Farmington Avenue Dental Research Division Guarulhos University, 88 Eng. Prestes Maia Street Laboratory of Technological Plasmas Institute of Science and Technology São Paulo State University (UNESP), 511 Três de Março Avenue Laboratory of Technological Plasmas Institute of Science and Technology São Paulo State University (UNESP), 511 Três de Março Avenue

Polymicrobial infection is the main cause of dental implant failure. Although numerous studies have reported the ability of titanium (Ti) surface modifications to inhibit microbial adhesion and biofilm accumulation, the majority of solutions for the utilization of Ti antibacterial surfaces have been testedin in vitro and animal models, with only a few developed surfaces progressing into clinical research. Motivated by this huge gap, we critically reviewed the scientific literature on the existing antibacterial Ti surfaces to help understand these surfaces' impact on the "puzzle" of undesirable dental implant-related infections. This manuscript comprises three main sections: (i) a narrative review on topics related to oral biofilm formation, bacterial-implant surface interactions, and on how implant-surface modifications can influence microbial accumulation; (ii) a critical evidence-based review to summarize pre-clinical and clinical studies in an attempt to "fit pieces into the puzzle" to unveil the best way to reduce microbial loads and control polymicrobial infection around dental implants showed by the current in vivo evidence; and (iii) discussion and recommendations for future research testing emerging antibacterial implant surfaces, connecting basic science and the requirements for future clinical translation. The findings of the present review suggest no consensus regarding the best available Ti surface to reduce bacterial colonization on dental implants. Smart release or on-demand activation surface coatings are a "new piece of the puzzle", which may be the most effective alternative for reducing microbial colonization on Ti surfaces, and future studies should focus on these technologies.

Made available in DSpace on 2022-05-01T08:44:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-12-01 Despite UV photolysis is common industrial water treatment, existent approaches are still not fully effective nor practical due to the growing amount of discharged effluents. Titanium dioxide (TiO2) has been used as a semiconductor for photocatalytic degradation of pollutants, but its efficiency is limited due to its rapid reverse reaction. Thus, novel approaches are needed to improve the quality and cost benefits of photocatalysts. In this study, the processing time effect of CeO2-Nb2O5 coatings on titanium synthesized via a one-step method of Plasma Electrolytic Oxidation (PEO) in an electrolytic solution containing ammonium niobium oxalate salt [NH4NbO(C2O4)2] and cerium oxide (CeO2) powder at 300, 450, and 600 s. The structural and optical properties, morphology, wettability, coating thickness, and elemental chemical composition were investigated. The performance of CeO2-Nb2O5 coatings regarding the photocatalytic activity was evaluated under UV irradiation, using methylene blue (MB) and metformin as model pollutants. Energy Dispersive Spectroscopy confirmed the incorporation of Ce and Nb into the oxide film. The Scanning Electron Microscopy demonstrated that the PEO process produced CeO2-Nb2O5 coatings with a thickness from 9.6 to 55.8 µm and irregular and porous structures that changed in proportion and size according to treatment time. X-ray diffraction (XRD) analysis revealed that the coatings demonstrated crystallization corresponding to CeO2 and Nb2O5 phases. All the experimental groups presented an estimated band gap of 3.3 eV, suggesting that the obtained coatings could be active in the UV light range. Also, such coatings showed an increased surface area that varied from 3.93 to 5.62 cm2 as high it was the treatment time, which could facilitate the degradation of pollutants. These results were consistent with the photocatalytic activity assay, where samples treated for 600 s showed the most significant degradation of MB under UV irradiation, especially at 15 and 30 min of irradiation when compared to untreated titanium and photolysis process (p < 0.05). Regarding metformin, after 120 min of UV exposure, 27% was degraded due to photolysis. Whereas after 210 min, 67% of the pharmaceutical degradation was observed on the 600 s-treated CeO2-Nb2O5 coating. A crystalline CeO2-Nb2O5 coating with improved surface characteristics and photocatalytic activity was synthesized by tailoring the treatment time process. This study makes advantageous for degrading pollutants and medicines, since sewage treatment systems are sometimes slow or not fully effective. Laboratory of Technological Plasmas São Paulo State University (UNESP), Av. Três de Março, 511, Aparecidinha Department of Physics Chemistry and Mathematics UFSCar Department of Prosthodontics and Periodontology Piracicaba Dental School UNICAMP Laboratory of Technological Plasmas São Paulo State University (UNESP), Av. Três de Março, 511, Aparecidinha

Este estudo investigou o comportamento corrosivo do titânio (Ti) em diferentes condições bucais: saliva artificial com pH 3; 6,5 e 9; e em simulador de fluido corpóreo (SFC) com pH 7,4. Os discos de Ti (10 mm x 2 mm) foram polidos com lixas sequenciais. O teste eletroquímico foi realizado usando um método padrão de 3 eletrodos. Foi realizada a espectroscopia de impedância eletroquímica para adquirir a resistência à polarização (Rp) e a capacitância (Q). A densidade de corrente de corrosão (Icorr), a densidade de corrente de passivação (Ipass) e a taxa de corrosão foram obtidas a partir das curvas de polarização. ANOVA one-way e teste de Tukey (α=0,05) foram utilizados na análise estatística. A SFC diminuiu a resistência à polarização quando comparada à saliva artificial em pH 6,5 e 9 (p0,05). A saliva artificial com pH 9 apresentou os menores valores de Icorr, Ipass e taxa de corrosão quando comparados com a SFC e a saliva com pH 3 (p

Made available in DSpace on 2020-12-12T02:44:32Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-09-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Objective: Overcoming substantial shortcomings of soft liners as physico-chemical changes and liner-biofilm-related infections remains a challenge in the rehabilitation treatment. In this study, protective non-thermal plasma (NTP) treatments were developed on the soft liner surface to improve its surface and physico-chemical properties and to reduce fungal colonization after biofilm inhibition challenge. Methods: Resinous liner specimens (Coe-Soft) were prepared and distributed in 3 groups according to the surface treatments: (1) untreated (control); (2) treated with sulfur hexafluoride-based NTP (SF6); and (3) treated with hexamethyldisiloxane-based NTP (HMDSO). To test the NTP stability and their protective and antimicrobial effect on the liner surface over time, the morphology, chemical composition, roughness, water contact angle, shore A hardness, sorption and solubility were evaluated before and after the specimens were exposed to dual-species biofilm of Candida albicans and Streptococcus oralis for 14 days. Colony forming units and biofilm structure were assessed. Data were submitted to ANOVA and Tukey tests (α = 0.05). Results: Both treatments modified the surface morphology, increased hydrophobicity and roughness of the liner, and were effective to reduce C. albicans adhesion without affecting the commensal health-associated S. oralis. HMDSO presented chemical stability and lower hardness in both periods, whereas SF6 exhibited higher initial hardness than control and the highest sorption; contrarily, similar solubility was noted for all groups. Conclusion: HMDSO-based film showed improved physico-chemical properties and inhibited C. albicans biofilm. Thus, it has potential for use to control candida-related stomatitis and improve liner's stability even after being exposed to biofilm inhibition challenge. Department of Prosthodontics and Periodontology University of Campinas (UNICAMP) Piracicaba Dental School Department of Dental Materials and Prosthodontics São Paulo State University (UNESP) School of Dentistry Laboratory of Technological Plasmas São Paulo State University (UNESP) Institute of Science and Technology Department of Bioscience University of Campinas (UNICAMP) Piracicaba Dental School Department of Dental Materials and Prosthodontics São Paulo State University (UNESP) School of Dentistry Laboratory of Technological Plasmas São Paulo State University (UNESP) Institute of Science and Technology

Made available in DSpace on 2019-10-06T15:57:01Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-01-05 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Universidade Estadual Paulista This study developed an experimental quaternary titanium (Ti) alloy and evaluated its surface properties and electrochemical stability. The viability for a biofunctional surface treatment was also tested. Ti-35Nb-7Zr-5Ta (wt%) alloy was developed from pure metals. Commercially pure titanium (cpTi) and Ti-6Al-4V were used as controls. All groups had two surface conditions: untreated (machined surface) and modified by plasma electrolytic oxidation (PEO) (treated surface). The experimental alloy was successfully synthesized and exhibited β microstructure. PEO treatment created a porous surface with increased roughness, surface free energy, hardness and electrochemical stability (p < 0.05). For the machined surfaces, the Ti-Nb-Zr-Ta alloy presented the lowest hardness and elastic modulus (p < 0.05) and displayed greater polarization resistance relative to cpTi. Only PEO-treated cpTi and Ti-Al-V alloys exhibited anatase and rutile as crystalline structures. The β experimental Ti-Nb-Zr-Ta alloy seems to be a good alternative for the manufacture of dental implants, since it presents elastic modulus closer to that of bone, feasibility for surface treatment, electrochemical stability and absence of toxic elements. University of Campinas (UNICAMP) Piracicaba Dental School Department of Prosthodontics and Periodontology, Av. Limeira, 901 Institute of Biomaterials Tribocorrosion and Nanomedicine (IBTN) Faculdade de Ciências do Tocantins (FACIT), Av. José de Brito, 730 Centro Universitário Tocantinense Presidente Antônio Carlos (UNITPAC), Av. Filadélfia, 568 São Paulo State University (UNESP) Engineering College Laboratory of Technological Plasmas, Av. Três de Março, 511 Univ. Estadual Paulista (UNESP) Araraquara Dental School Department of Dental Materials and Prosthodontics, R. Humaitá São Paulo State University (UNESP) Engineering College Laboratory of Technological Plasmas, Av. Três de Março, 511 Univ. Estadual Paulista (UNESP) Araraquara Dental School Department of Dental Materials and Prosthodontics, R. Humaitá FAPESP: 2016/11470-6 FAPESP: 2017/01320-0