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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

PURPOSE To investigate the influence of nonthermal plasma (NTP) treatment on the tensile bond strength between heat-polymerized acrylic resin for ocular prostheses and silicone reliner, with and without the use of an adhesive primer. MATERIALS AND METHODS One-hundred and sixty-four acrylic resin specimens were fabricated and randomly distributed into four groups according to the type of surface treatment: Sofreliner Primer, NTP, Sofreliner Primer + NTP, and NTP + Sofreliner Primer. Two specimens interposed with relining material (Sofreliner) formed one test sample to perform the tensile bond strength tests, before (initial) and after storage (final) in saline solution (37°C, 90 days, n = 10). Surface characterization was performed by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The failure type was classified as cohesive, adhesive, or mixed. The data were analyzed statistically using the two-way ANOVA and Tukey test, as well as the chi-squared test (α = 0.05), Bonferroni correction (α = 0.005), and Spearman correlation coefficient (α = 0.05). RESULTS The SEM and EDS analyses showed the presence of a thin, homogenous organic film in the groups treated with NTP. The NTP + Sofreliner Primer group presented the largest bond strength mean values in the initial period (p < 0.05). Sofreliner Primer and NTP + Sofreliner Primer groups presented the first and second largest tensile bond strength mean values in the final period (p < 0.05), respectively. NTP + Sofreliner Primer group also had the largest number of cohesive (70%, initial) and mixed (90%, final) failures. CONCLUSIONS The NTP treatment performed before the primer application enhanced the bond between the acrylic resin ocular prosthesis and the Sofreliner silicone-based reliner, even after 90 days of immersion in saline solution.

Summary Implant devices have = proven a successful treatment modality in reconstructive surgeries. However, increasing rates of peri-implant diseases demand further examination of their pathogenesis. Polymicrobial biofilm formation on titanium surfaces has been considered the main risk factor for inflammatory processes on tissues surrounding implant devices, which often lead to implant failure. To overcome microbial accumulation on titanium surfaces biofilm targeting strategies have been developed to modify the surface and incorporate antimicrobial coatings. Because antibiotics are widely used to treat polymicrobial infections, these agents have recently started to be incorporated on titanium surface. This review discusses the biofilm formation on titanium dental implants and key factors to be considered in therapeutic and preventative strategies. Moreover, a systematic review was conducted on coatings developed for titanium surfaces using different antibiotics. This review will also shed light on potential alternative strategies aiming to reduce microbial loads and control polymicrobial infection on implanted devices., Graphical Abstract, Highlights • Polymicrobial biofilms are the main etiologic factor of implant-related infections • Titanium (Ti) biomaterial is a substrate for microbial accumulation • Antibiotic-loaded coating on titanium is a promising strategy this accumulation • These strategies need to improve drug releasing and are tested by polymicrobial models, Microbiofilms; Surface Science

Titanium(IV) oxide (TiO2) and zirconium(IV) oxide (ZrO2) are well-known materials for their biocompatibility, hydrophilicity, antimicrobial activity, and excellent mechanical properties. Polymethyl methacrylate (PMMA), on the other hand, has many applications in medicine, biomedical systems, and engineering. However, its poor surface and mechanical properties limit its applications. The purpose of this study is how functionalization of PMMA would provide surface protection and reduce microbial adherence and biofilm formation. Hence, low-temperature Atomic Layer Deposition (ALD) was used to deposit TiO2, ZrO2, and TiO2/ZrO2 mixed oxides nanofilms on PMMA substrates. Surface composition was examined and Ti:Zr ratios were calculated through x-ray photoelectron spectroscopy. The coatings increased wettability and slightly enhanced nanohardness of PMMA. No significant change was observed in the surface roughness of PMMA after ALD. The nanocoatings protected the PMMA surface from thermal and brushing challenges by maintaining wettability, surface roughness, and film integrity. Additionally, compared to control, the mixed oxides with 1:2 cycle ratio of TiO2:ZrO2 showed a significant reduction on all bacterial and fungal initial adhesion and biofilm formation, while the TiO2 film provided reduction at initial fungal adhesion. Thus, TiO2/ZrO2 ALD on PMMA could enhance its surface, mechanical, and biological properties, preparing it for biomedical and engineering applications.

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

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