Fluoroammonium method for processing of cake from leaching of titanium-magnesium production sludge

We present the results of the physical and chemical properties of cake from nitric-acid leaching of titanium production sludge. It was found that all silicon in the cake is in the form of quartz, albite, sillimanite, sodium aluminosilicate. In total, these minerals make up the majority of the cake 60.24%. Titanium is presented in the form of rutile, titanium aluminum oxide, which in total is 35.56%. Iron is part of sillimanite and hematite, the total content of which is about 4.2%. The optimal parameters of fluoroammonium processing of cake were determined: silicon distillation into sublimates at 300°С for 6 hours, sublimation of titanium in the form of titanium tetrafluoride at 800°С for 2 hours. The process of alkaline hydrolysis of sublimates of fluoride compounds and cinder was carried out. Purification of impurities and calcination of hydrated titanium dioxide were carried out. The resulting titanium and silicon dioxide products contain: 96.2% TiO2, 88 % SiО2, respectively; a niobium-containing intermediate product with a content of 11.6 % Nb2O5 was also obtained.

In vitro effect of experimental nanocomposites solutions on the prevention of dental caries around orthodontic brackets

This study aimed to evaluate the in vitro effect of a single application of experimental nanocomposite solutions on the prevention of dental caries around orthodontic brackets. The specimens were exposed to mesoporous silica (MS) nanocomposites containing fluoride by association with titanium tetrafluoride (TiF4) or sodium fluoride (NaF). Nanocomposites also could contain calcium and groups were described as MSCaTiF4, MSTiF4, MSCaNaF, MSNaF, and controls (TiF4, and NaF). Specimens were subjected to the formation of a multispecies biofilm to generate a cariogenic challenge. After 24h, both pH and total soluble fluoride concentration of the culture medium were assessed. Mineral loss was evaluated by percentage of surface mineral loss (%SML), mineral volume variation (ΔZ) of inner enamel and polarized light microscopy (PL). Linear (Ra) and volumetric (Sa) surface roughness and scanning electronic microscopy (SEM) were used to assess enamel topography. Statistical analyses were conducted considering p<0.05. MSNaF had the highest value of culture medium pH after cariogenic challenge, similarly to MSTiF4. All nanocomposite solutions released less fluoride than their controls NaF and TiF4 (p<0.05). All nanocomposite solutions presented lower %SML compared to their respective control groups (p<0.05). Lower Ra, Sa and ΔZ were observed for experimental groups compared to TiF4 (p<0.05). The results were confirmed by PL and SEM analysis. The experimental nanocomposite solutions contributed for lower enamel demineralization around orthodontic brackets.

Low-Temperature Synthesis of Titanium Oxynitride Nanoparticles

The synthesis of transition metal oxynitrides is complicated by extreme reaction conditions such as high temperatures and/or high pressures. Here, we show an unprecedented solution-based synthesis of narrowly dispersed titanium oxynitride nanoparticles of cubic shape and average size of 65 nm. Their synthesis is performed by using titanium tetrafluoride and lithium nitride as precursors alongside trioctylphosphine oxide (TOPO) and cetrimonium bromide (CTAB) as stabilizers at temperatures as low as 250 °C. The obtained nanoparticles are characterized in terms of their shape and optical properties, as well as their crystalline rock-salt structure, as confirmed by XRD and HRTEM analysis. We also determine the composition and nitrogen content of the synthesized particles using XPS and EELS. Finally, we investigate the applicability of our titanium oxynitride nanoparticles by compounding them into carbon fiber electrodes to showcase their applicability in energy storage devices. Electrodes with titanium oxynitride nanoparticles exhibit increased capacity compared to the pure carbon material.

Protective effect of titanium tetrafluoride and silver diamine fluoride on radiation-induced dentin caries in vitro

This in vitro study evaluated the protective effect of titanium tetrafluoride (TiF4) varnish and silver diamine fluoride (SDF) solution on the radiation-induced dentin caries. Bovine root dentin samples were irradiated (70 Gy) and treated as follows: (6 h): 4% TiF4 varnish; 5.42% NaF varnish; 30% SDF solution; placebo varnish; or untreated (negative control). Microcosm biofilm was produced from human dental biofilm (from patients with head-neck cancer) mixed with McBain saliva for the first 8 h. After 16 h and from day 2 to day 5, McBain saliva (0.2% sucrose) was replaced daily (37 °C, 5% CO2) (biological triplicate). Demineralization was quantified by transverse microradiography (TMR), while biofilm was analyzed by using viability, colony-forming units (CFU) counting and lactic acid production assays. The data were statistically analyzed by ANOVA (p < 0.05). TiF4 and SDF were able to reduce mineral loss compared to placebo and the negative control. TiF4 and SDF significantly reduced the biofilm viability compared to negative control. TiF4 significantly reduced the CFU count of total microorganism, while only SDF affected total streptococci and mutans streptococci counts. The varnishes induced a reduction in lactic acid production compared to the negative control. TiF4 and SDF may be good alternatives to control the development of radiation-induced dentin caries.

Sensitivity treatments for teeth with Molar-Incisor Hypomineralization (MIH): Protocol for a Randomized Controlled Trial (Preprint)

BACKGROUND The sensitivity of teeth with MIH (Molar Incisor Hypomineralization) can affect children’s quality of life and is a challenging problem for dentists. Remineralizing agents such as sodium fluoride varnish seem to reduce sensitivity of teeth with MIH, but long-term clinical trials with large samples are still needed for more consistent results about its effectiveness as a desensitizing agent before its clinical recommendation. OBJECTIVE This randomized clinical trial aims to compare three treatment interventions for teeth with MIH and hypersensitivity. METHODS : 60 children aged 6-10 years presenting with at least one first permanent molar with sensitivity and no loss of enamel will be randomly assigned to three groups: Control group - sodium fluoride varnish (Duraphat®, Colgate); Experimental group I - 4% titanium tetrafluoride varnish (TiF4); and Experimental group II - coating resin containing S-PRG filler (Surface Pre-Reacted Glass ionomer) (SPRG Barrier Coat®, Shofu). The sodium fluoride varnish and 4% titanium tetrafluoride varnish will be applied once a week for 4 consecutive weeks and the S-PRG-Barrier Coat resin will be applied in the first session and the application will be simulated in the following 3 weeks to guarantee the blinding of the study. The primary outcome will be sensitivity level measured in different moments: before each material application, immediately after application or simulation, and 1, 2, 4, and 6 months after the last application/simulation by one examiner using Wong-Baker Facial Scale (WBFS), Schiff's Cold Air Sensitivity Scale (SCASS), and FLACC Pain Scale (Face, Legs, Activity, Cry, Consolability pain scale). As secondary outcomes, the parental satisfaction and child self-reported discomfort after the treatment will be measured with a questionnaire prepared by the researcher. The data will undergo statistical analysis and the significance level will be set at 5%. RESULTS The project was funded in 2018, and enrollment was completed in November 2019. The recruitment of participants is currently under way and the first results are expected to be submitted for publication in 2022. CONCLUSIONS If found effective in reducing the patient’s sensitivity with long-term effects, these agents can be considered a treatment choice, and the findings will contribute with the development of a treatment protocol for teeth with sensitivity due to MIH. CLINICALTRIAL Brazilian Registry of Clinical Trials Universal Trial Number: U1111-1237-6720; http://www.ensaiosclinicos.gov.br/rg/?q=RBR-4BHXPB

Synergistic Effect between Zr-MOF and Phosphomolybdic Acid with the Promotion of TiF4 Template

Metal-Organic Framework (MOF) materials are often modified or functionalized, and then the crystal size and morphology of MOF materials are changed. In the process of preparing UiO-66 confined phosphomolybdic acid (PMA) composites (PU), the TiF4-modified PU (PMA + UiO-66) composite catalyst (TiF4-PU) was successfully synthesized by adding titanium tetrafluoride, and the catalytic desulfurization activity was excellent. Similarly, the reaction mechanism was investigated by means of infrared spectroscopy, Raman spectroscopy, XPS, and UV/Vis spectroscopy. The results show that the addition of TiF4 not only changes the appearance and color of the catalyst, but also changes the valence distribution of the elements in the catalyst. The number of oxygen vacancies in the MOF increases due to the addition of TiF4, and more electrons are transferred from the Zr-MOF to PMA to form more Mo5+, which improved the performance of oxidative desulfurization in comparison. Thus, a stronger strong metal-support interaction (SMSI) effect is observed for TiF4-modified PU catalysts. In addition, the quenching experiment of free radicals shows that ·OH radical is the main active substance in the oxidative desulfurization reaction over TiF4-PU catalyst.