One-step rapid formation of wrinkled fractal antibiofouling coatings from environmentally friendly, waste-derived terpenes.

Wrinkled coatings are a potential drug-free method for mitigating bacterial attachment and biofilm formation on materials such as medical and food grade steel. However, their fabrication typically requires multiple steps and often the use of a stimulus to induce wrinkle formation. Here, we report a facile plasma-based method for rapid fabrication of thin (<250 nm) polymer coatings from a single environmentally friendly precursor, where wrinkle formation and fractal pattern development are controlled solely by varying the deposition time from 3 s to 60 s. We propose a mechanism behind the observed in situ development of wrinkles in plasma, as well as demonstrate how introducing specific topographical features on the surface of the substrata can result int the formation of even more complex, ordered wrinkle patterns arising from the non-uniformity of plasma when in contact with structured surfaces. Thus-fabricated wrinkled surfaces show good adhesion to substrate and an antifouling activity that is not observed in the equivalent smooth coatings and hence is attributed to the specific pattern of wrinkles.

Non-thermal plasma for surface treatment of inorganic fillers added to resin-based cements.

OBJECTIVES: This study aims to evaluate the effect of non-thermal plasma (NTP) surface treatment in two composite inorganic fillers and evaluate their impact on the chemical-mechanical properties and bond strength ability of experimental resin cements. MATERIALS AND METHODS: Ytterbium fluoride (YF) and barium silicate glass (BS) were characterized and submitted to different surface treatments: non-thermal plasma (NTP); non-thermal plasma and 3-(trimethoxysilyl) propyl methacrylate silanization; and 3-(trimethoxysilyl) propyl methacrylate silanization. Untreated fillers were used as a control. The fillers were incorporated at 65wt% concentration into light-cured experimental resin cements (50wt% BisGMA; 25wt% UDMA; 25wt% TEGDMA; 1mol% CQ). The degree of conversion, the flexural strength, and the microshear bond strength (µSBS) were evaluated to characterize developed composites. RESULTS: YF and BS were successfully cleaned with NTP treatment. Nor NTP neither the silanization affected the degree of conversion of resin cements. The NTP predicted an increase in YF-containing resin cements flexural strength, reducing the storage impact in these materials. NTP treatment did not affect the µSBS when applied to YF, while silanization was effective for BS-containing materials. CONCLUSION: NTP treatment of inorganic particles was possible and was shown to reduce the amount of organic contamination of the particle surface. YF surface treatment with NTP can be an alternative to improve the organic/inorganic interaction in resin composites to obtain materials with better mechanical properties. CLINICAL RELEVANCE: Surface cleaning with NTP may be an alternative for particle surface cleaning to enhance organic-inorganic interaction in dental composites resulting in improved mechanical strength of experimental resin cements.

Cerium Dioxide Particles to Tune Radiopacity of Dental Adhesives: Microstructural and Physico-Chemical Evaluation.

The insufficient radiopacity of dental adhesives applied under composite restorations makes the radiographic diagnosis of recurrent caries challenging. Consequently, the misdiagnosis may lead to unnecessary replacement of restorations. The aims of this study were to formulate experimental dental adhesives containing cerium dioxide (CeO2) and investigate the effects of different loadings of CeO2 on their radiopacity and degree of conversion for the first time. CeO2 was characterized by X-ray diffraction analysis, Fourier transforms infrared spectroscopy, and laser diffraction for particle size analysis. Experimental dental adhesives were formulated with CeO2 as the inorganic filler with loadings ranging from 0.36 to 5.76 vol.%. The unfilled adhesive was used as a control. The studied adhesives were evaluated for dispersion of CeO2 in the polymerized samples, degree of conversion, and radiopacity. CeO2 presented a monoclinic crystalline phase, peaks related to Ce-O bonding, and an average particle size of around 16 µm. CeO2 was dispersed in the adhesive, and the addition of these particles increased the adhesives' radiopacity (p < 0.05). There was a significant decrease in the degree of conversion with CeO2 loadings higher than 1.44 vol.%. However, all materials showed a similar degree of conversion in comparison to commercially available adhesives. CeO2 particles were investigated for the first time as a promising compound to improve the radiopacity of the dental adhesives.

Osteogenic differentiation of bone marrow-derived mesenchymal stem cells on anodized niobium surface.

Currently, titanium and its alloys are the most used materials for biomedical applications. However, because of the high costs of these metals, new materials, such as niobium, have been researched. Niobium appears as a promising material due to its biocompatibility, and excellent corrosion resistance. In this work, anodized niobium samples were produced and characterized. Their capacity to support the osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BM-MSCs) was also tested. The anodized niobium samples were characterized by SEM, profilometry, XPS, and wettability. BM-MSCs were cultured on the samples during 14 days, and tested for cell adhesion, metabolic activity, alkaline phosphatase activity, and mineralization. Results demonstrated that anodization promotes the formation of a hydrophilic nanoporous oxide layer on the Nb surface, which can contribute to the increase in the metabolic activity, and in osteogenic differentiation of BM-MSCs, as well as to the extracellular matrix mineralization.

Niobium pentoxide phosphate invert glass as a mineralizing agent in an experimental orthodontic adhesive.

OBJECTIVE: The aim of this study was to develop an experimental orthodontic adhesive and evaluate how adding phosphate invert glass containing niobium pentoxide (PIG-Nb) affected the adhesive's properties. MATERIAL AND METHODS: PIG-Nb was added at 1, 2.5, and 5 wt% to experimental adhesive (75 wt% bisphenol A methacrylate [BisGMA], 25 wt% triethylene glycol dimethacrylate [TEGDMA], 5 wt% colloidal silica and photoinitiator system). The adhesives were evaluated for mineral deposition, degree of conversion (DC), softening solvent by Knoop microhardness (KNH) variation, pH changes, and shear bond strength (SBS). One-way analysis of variance (ANOVA) (DC and ΔKHN%), two-way ANOVA (SBS), repeated measures ANOVA (pH), and paired test (KNH1 and KNH2) were used at a significance level of P < .05. RESULTS: Adding PIG-Nb to orthodontic adhesives induced deposition on its surface associated with a constant neutral pH. The SBS increased after immersion in artificial saliva, and the PIG-Nb5 exhibited less softening. CONCLUSION: The addition of PIG-Nb into orthodontic adhesives induced mineral deposition. Experimental orthodontic adhesive containing 5% wt of PIG-Nb exhibited increased mineral deposition and suitable properties for orthodontic applications.

In vitro antibacterial and remineralizing effect of adhesive containing triazine and niobium pentoxide phosphate inverted glass.

OBJECTIVES: White spot lesions are still a concern for orthodontic patients. The objective of this study was to assess the remineralizing and antibacterial effect of a newly developed orthodontic adhesive. METHODS: The compounds 1,3,5-tryacryloylhexahydro-1,3,5-triazine (TAT) and phosphate invert glass containing 10 mol% of niobium pentoxide (PIG-Nb) were added at 20 and 5 wt%, respectively, to an experimental adhesive (75 wt% BisGMA, 25 wt% TEGDMA, 5 wt% fummed silica, and photo-initiator system), called TPN. A group without the addition of these compounds was used as Control and the orthodontic adhesive Transbond XT (TXT) was used for comparison. Antibacterial activity was evaluated through surface biofilm formation, mineral deposition, and degree of conversion (DC) through Raman microscopy, Knoop hardness after softening in solvent, and bracket dislodgement (BD). RESULTS: TPN group presented a reduction in bacterial growth when compared to Control and TXT. Mineral deposits were observed on the surface of TPN adhesive after 14 and 28 days of immersion in artificial saliva. There was an increase in DC after 28 days, whereas TPN group presented the highest DC. All groups underwent some degree of softening. No significant changes were observed in BD after 28 days of immersion in artificial saliva. CONCLUSION: The newly developed orthodontic adhesive, with addition of 20 wt% TAT and 5w% PIG-Nb, exhibited antibacterial activity and was capable to induce mineral deposition on its surface in vitro. CLINICAL SIGNIFICANCE: The orthodontic adhesive developed in this study with antibacterial activity and mineral deposition could be a reliable choice for brackets adhesion.

Physicochemical and bioactive properties of innovative resin-based materials containing functional halloysite-nanotubes fillers.

OBJECTIVE: This study aimed to assess the degree of conversion, microhardness, solvent degradation, contact angle, surface free energy and bioactivity (e.g., mineral precipitation) of experimental resin-based materials containing, pure or triclosan-encapsulated, aluminosilicate-(halloysite) nanotubes. METHODS: An experimental resin blend was prepared using bis-GMA/TEGDMA, 75/25wt% (control). Halloysite nanotubes (HNT) doped with or without triclosan (TCN) were first analyzed using transmission electron microscopy (TEM). HNT or HNT/TCN fillers were incorporated into the resin blend at different concentrations (5, 10, and 20wt%). Seven experimental resins were created and the degree of conversion, microhardness, solvent degradation and contact angle were assessed. Bioactive mineral precipitation induced by the experimental resins was evaluated through Raman spectroscopy and SEM-EDX. RESULTS: TEM showed a clear presence of TCN particles inside the tubular lumen and along the outer surfaces of the halloysite nanotubes. The degree of conversion, surface free energy, microhardness, and mineral deposition of polymers increased with higher amount of HNTs. Conversely, the higher the amount (20wt%) of TCN-loaded HNTs the lower the microhardness of the experimental resins. SIGNIFICANCE: The incorporation of pure or TCN-loaded aluminosilicate-(halloysite) nanotubes into resin-based materials increase the bioactivity of such experimental restorative materials and promotes mineral deposition. Therefore, innovative resin-based materials containing functional halloysite-nanotube fillers may represent a valuable alternative for therapeutic minimally invasive treatments.