Analysis of parabens in dentifrices and the oral cavity

This study analyzed levels of parabens in commercial dentifrices and saliva. HPLC was performed using 35% acetonitrile and measuring absorbance at 254 nm. Thirteen toothpastes and five mouthwashes were analyzed. Of these, volunteers used three toothpastes and two mouthwashes, and levels of parabens were analyzed in saliva and water used for mouth rinsing. In toothpastes, the highest concentrations of methylparaben (MP), propylparaben (PP) and n‐butylparaben (nBP) were 1.86, 1.42 and 1.87 mg/g, respectively. In mouthwashes, the highest concentrations of MP and PP were 0.97 and 0.11 mg/mL, respectively. After volunteers used 500 mg toothpaste T‐1, which contained 895 µg MP, the first and tenth mouth rinse samples contained means of 64.63 and 1.89 µg MP, respectively. After rinsing the mouth three or five times, 37 µg or 18 µg MP was calculated to remain in the oral cavity, respectively. After using 20 mL mouthwash S‐1, which contained 19 mg MP, 1.53 mg MP was calculated to remain in the oral cavity. Immediately after using this mouthwash, the mean salivary concentration of MP was 237 µg/mL. The daily intake of parabens from dentifrices was predicted to be insignificant compared with the intake from food; however, parabens can be ingested from dentifrices. Copyright © 2014 John Wiley & Sons, Ltd.     

Composition Profiles of Dental Enamel Studied by X-Ray Photoelectron Spectroscopy (ESCA)

Abstract

The surfaces of both normal and fluoride treated human dental enamel were examined with x-ray photoelectron spectroscopy (ESCA). Using argon-ion etching to remove thin layers of enamel, subsurface layers were also analyzed. The resulting composition-depth profile showed that stannous fluoride produced a subsurface layer containing both tin and fluoride whereas fluorine was absent from the surface layer. Acid fluoride treatments, however, converted the surface to calcium fluoride which steadily decreased in concentration with depth.     

Synthesis of Homoallylic Alcohols From Ketones in Water

Homoallylic alcohols have been prepared in good yields by allylation of ketones with allyl bromide in the presence of stannous chloride dihydrate, zinc iodide, and ammonium chloride in water.     

Exploring the Potential of Natural Product-Based Nanomedicine for Maintaining Oral Health

Oral diseases pose a major threat to public health across the globe. Diseases such as dental caries, periodontitis, gingivitis, halitosis, and oral cancer affect people of all age groups. Moreover, unhealthy diet practices and the presence of comorbidities aggravate the problem even further. Traditional practices such as the use of miswak for oral hygiene and cloves for toothache have been used for a long time. The present review exhaustively explains the potential of natural products obtained from different sources for the prevention and treatment of dental diseases. Additionally, natural medicine has shown activity in preventing bacterial biofilm resistance and can be one of the major forerunners in the treatment of oral infections. However, in spite of the enormous potential, it is a less explored area due to many setbacks, such as unfavorable physicochemical and pharmacokinetic properties. Nanotechnology has led to many advances in the dental industry, with various applications ranging from maintenance to restoration. However, can nanotechnology help in enhancing the safety and efficacy of natural products? The present review discusses these issues in detail.     

Simultaneous determination of fluoride and monofluorophosphate in toothpastes by supressed ion chromatography

Suppressed ion chromatography with a highly selective and high capacity anion-exchange column is used for the determination of anionic compounds in ten commercially available toothpastes. Minimal sample preparation is needed, requiring only dilution and filtration over a solid-phase extraction cartridge. Quantitative analysis of fluoride and monofluorophosphate, as well as chloride, nitrate, orthophosphate, and sulfate is achieved in one chromatographic run with a total analysis time of 25 minutes. Optimized analytical conditions are validated in terms of accuracy, precision, and total uncertainty, and the results demonstrate the reproducibility of ion chromatography. The coefficient of determination for the anions ranges from 0.9896 to 0.9997. The spiked recoveries for the anions are 88–108%. The change in the fluoride content of the toothpaste with storage time is investigated.     

Enhancement of Sensitivity for Selenium Determination in Atomic Absorption Spectrophotometry by Introducting Hydrogen Selenide into an Argon-Hydrogen Flame

Abstract

The sensitivity for selenium determination with atomic absorption spectrophotometry is enhanced to a large extent by introducing hydrogen selenide gas into an argon-hydrogen flame. As a reducing agent, zinc granular and stannous chloride is successfully used for quantitative and rapid productions of hydrogen selenide from selenium(IV) solution. The sensitivity for 1 % absorption of the signal is estimated to be about 0.02 ppm of selenium.     

Marine Bacterial Dextranases: Fundamentals and Applications

Dextran, a renewable hydrophilic polysaccharide, is nontoxic, highly stable but intrinsically biodegradable. The α-1, 6 glycosidic bonds in dextran are attacked by dextranase (E.C. 3.2.1.11) which is an inducible enzyme. Dextranase finds many applications such as, in sugar industry, in the production of human plasma substitutes, and for the treatment and prevention of dental plaque. Currently, dextranases are obtained from terrestrial fungi which have longer duration for production but not very tolerant to environmental conditions and have safety concerns. Marine bacteria have been proposed as an alternative source of these enzymes and can provide prospects to overcome these issues. Indeed, marine bacterial dextranases are reportedly more effective and suitable for dental caries prevention and treatment. Here, we focused on properties of dextran, properties of dextran—hydrolyzing enzymes, particularly from marine sources and the biochemical features of these enzymes. Lastly the potential use of these marine bacterial dextranase to remove dental plaque has been discussed. The review covers dextranase-producing bacteria isolated from shrimp, fish, algae, sea slit, and sea water, as well as from macro- and micro fungi and other microorganisms. It is common knowledge that dextranase is used in the sugar industry; produced as a result of hydrolysis by dextranase and have prebiotic properties which influence the consistency and texture of food products. In medicine, dextranases are used to make blood substitutes. In addition, dextranase is used to produce low molecular weight dextran and cytotoxic dextran. Furthermore, dextranase is used to enhance antibiotic activity in endocarditis. It has been established that dextranase from marine bacteria is the most preferable for removing plaque, as it has a high enzymatic activity. This study lays the groundwork for the future design and development of different oral care products, based on enzymes derived from marine bacteria.     

In situ and ex situ characterization of a Fe-Cr-Ni alloy in mouthwashes and Hank’s solution

The aim of the present study was to classify the surface oxide layers formed on a Fe-Cr-Ni alloy according to their corrosion resistance in Hank’s solution and mouthwashes by SEM and electrochemical techniques. The SEM micrographs showed the presence of localized corrosion and the polarization curves showed that the passive layer is less stable in the presence of Hank’s solution than of mouthwashes, as a result of the presence of chloride ions.     

Salivary MMP-9 Levels in Chronic Periodontitis Patients with Type-II Diabetes Mellitus

Chronic periodontitis and diabetes mellitus share a two-way relationship, the common factor being the inflammatory-mediated pathway, and various cytokines are released during this inflammatory cascade, one of which being matrix metalloproteinase-9. The aim of this study was to identify whether the levels of matrix metalloproteinase-9 are increased due to type-II diabetes mellitus in chronic periodontitis patients. It was an observational, analytical, case-control study. Thirty subjects were recruited in the test group, who were suffering from type-II diabetes mellitus and chronic periodontitis, and 30 subjects in the control group, who were subjects with chronic periodontitis but systemically healthy. Periodontal parameters, including the plaque score, gingival bleeding index, probing pocket depth and clinical attachment level of the subjects, were measured, saliva samples of all of the subjects were collected and salivary matrix metalloproteinase-9 levels were analyzed by an enzyme-linked immunosorbent assay (ELISA) technique. The statistical analysis was performed using SPSS 24. Overall, the matrix metalloproteinase-9 levels of the diabetic patients with chronic periodontitis were increased almost twofold (156.95 ± 29.80 ng/mL) compared to the levels in the controls (74.96 ± 6.32 ng/mL) (p < 0.001). Similarly, the periodontal parameters were far worse in diabetics with chronic periodontitis compared to the controls. The average gingivitis score for the test subjects was 78.45 ± 8.93%), compared to 29.32 ± 12.96% in the controls (p < 0.001). The mean probing pocket depth for the test group was 5.39 ± 0.60 mm, and, for the control group, it was 4.35 ± 0.31 mm (p < 0.001). For the test subjects, the average clinical attachment level was 5.86 ± 0.58 mm, and it was 4.66 ± 0.32 mm for the controls (p < 0.001). It was ascertained that there is a two-fold increase in the levels of salivary matrix metalloproteinase-9 in the test group compared to the control group. In addition, the level of periodontal apparatus destruction was greater in the test group. This proved that type-II diabetes mellitus influences the levels of matrix metalloproteinase-9 in humans and elevates them, causing further periodontal destruction.     

A 119mSn Mossbauer study of the thermal degradation of PVC stabilised by various organotin(IV) and tin(II) compounds

^119mSn Mossbauer spectroscopy has been used to study the chemical changes undergone by a range of tin-containing stabilisers (dialkyltin dilaurates, dialkyltin bis(ethylcysteinates), stannous stearate and stannous cysteinate) during thermal degradation of PVC at 185°C. The dialkyltin-laurate and -cysteinate stabilisers are converted to the dialkyltin dichlorides. Stannous stearate and stannous cysteinate are rapidly converted into stannic oxide and stannic chloride, respectively.     

Screening for Antimicrobials in Mouthwashes Using HPTLC-Bioluminescence Detection

One of the tasks of food law enforcement authorities is to supervise the composition of cosmetics. In the case of mouthwashes, they are likely to contain (labeled or unlabeled) antimicrobial compounds. Conventional analyses, such as high-performance liquid chromatography (HPLC) and gas chromatography (GC) only shed light on a compound’s structure, but not on its biological function. In this study, we demonstrate that the task of detecting antimicrobials in mouthwashes can be streamlined using the luminescent bacterium Vibrio fischeri as a biodetector coupled with high-performance thin-layer chromatography (HPTLC) as a pre-separation method. The employment of subsequent conventional techniques could then be restricted to fractions with proven V. fischeri toxicity. Samples were separated in parallel on silica gel and amino layer HPTLC plates, developed with a solvent system containing tertiary butyl methyl ether and n-hexane and dried on a plate heater. After applying V. fischeri onto the HPTLC plate, zones of interest were extracted from a parallel plate and identified by HPLC–UV or GC-mass spectrometry. The reaction of V. fischeri to more than 40 standard substances which might be present in mouthwashes was determined. Based on this information, six commercially available mouthwashes were analyzed. The workflow proved to be viable for an effect-directed screening for antimicrobial compounds. The analysis of mouthwashes revealed that not only declared preservatives are used (sodium benzoate, cetylpyridinium chloride) but also other compounds, especially constituents of essential oils. Because their main purpose is flavoring of the mouthwash, they are summarized as “aroma” (anethole, carvone, menthol, thymol) which is in compliance with legal restrictions.     

Selenophilicity of Copper in Selenium-Carbon Bond Formation from Selenous Acid Using Cu(II)/Sn(II) Reagent

A selenium transfer reaction from selenous acid to benzyl and alkyl halides is initiated in the presence of stannous chloride and a catalytic amount of cupric chloride resulting in the formation of the corresponding diorganoselenides and/or diorganodiselenides as the major products as indicated by ¹ H, ¹³ C, ⁷⁷ Se NMR, and MS. The reaction is characterized by a dual-metal effect at the selenium activation and transfer step. Thus, initial reaction of stannous chloride, cupric chloride, and selenous acid gives rise to α-Cu ₂ Se. Selenium transfer from the latter to the organic halide takes place with additional assistance of stannous chloride.     

A potentiometric method for the determination of uranium by stannous chloride reduction

A potentiometric method has been developed for the determination of uranium using stannous chloride as reductant. The oxidation of excess stannous chloride was accomplished with an excess of sodium nitrite, the excess of which was destroyed by sulfamic acid. The U(IV) was then determined by potentiometric titration with standard potassium dichromate. For 3–5 mg amounts of uranium the precision obtained was better than 0.3%.     

Radiopharmaceuticals prepared with stannous chloride

The preparation of radiopharmaceuticals using stannous chloride has acquired an ever increasing importance. The applicability to a great number of compounds constitutes the basis of interest. The possibility of preparing kits has added to the desirable properties. The stannous ion is a powerful reducing agent, it posseses the quality of coprecipitating with numerous elements and favours the formation of many complexes of relatively low toxicity. The present outline is a panoramic appreciation of the radiopharmaceuticals prepared with the aid of stannous chloride, some brief considerations on quality control have found their way into this exposition.     

Supramolecular chemistry approach to the design of a high-resolution sensor array for multianion detection in water

Reliable sensing of structurally similar anions in water is a difficult problem, and analytical tests and sensor devices for reliable sensing of multiple anions are very rare. This study describes a method for fabrication of simple colorimetric array-based assays for aqueous anion solutions, including complex analytes encountered in real-life applications. On the fundamental level, this method shows how the discriminatory capacity of sensor arrays utilizing pattern recognition operating in multianalyte environments may be dramatically improved by employing two key features. The synergy between the sensor and hydrogel host resembles the cooperative effects of an apoenzyme and cofactor: the host hydrogel helps extract the target anions from the bulk analyte while stripping the solvate molecules off the anions. In addition, the supramolecular studies of the affinity and selectivity of the potential sensors for target analytes allow for constructing an array predesigned for a particular analyte. To illustrate both aspects, an eight-sensor array utilizing colorimetric sensor materials showing selectivity for fluoride and pyrophosphate while displaying significant cross-reactivity for other anions such as carboxylates, phosphate, or chloride was used to differentiate between 10 anions. The quantitative analyses were also performed to show that the eight-sensor array was found to operate across 4 orders of magnitude concentrations (0.20-360 ppm; 10 microM to 20 mM). The applicability of this approach was demonstrated by analyzing several toothpaste brands. The toothpastes are complex analytes comprising both known and unknown anions in various concentrations. The fluoride-selective yet cross-reactive array is shown to utilize the fluoride content as the main differentiating factor while using the remaining anionic components for further differentiation between toothpaste brands.     

Preparation,quality control and stability of <Superscript>99m</Superscript>Tc-cefuroxime axetil

Cefuroxime axetil, a cephalosporin antibiotic used to treat bacterial infections, was investigated to label with ^99mTc. Radiolabeling of cefuroxime axetil was carried out by using stannous chloride method. Effects of pH and stannous chloride amount on the radiolabeling yield were investigated. The radiochemical purity of ^99mTc-cefuroxime axetil was determined by thin layer radio chromatography (TLRC), electrophoresis and high performance liquid chromatography. The maximum radiolabeling yield was 98±1%.     

Synthesis of SnO2 nanostructures by ultrasonic-assisted sol–gel method

Fluorine doped SnO₂ nanostructures were grown using ultrasonic assisted sol–gel method. The gel was obtained by dissolving stannous chloride in methanol with ammonium fluoride as dopant followed by irradiation with ultrasonic vibrations. Obtained samples were characterized by structural, morphological and optical studies. All the peaks in the X-ray diffractograms are identified and indexed as tetragonal cassiterite structure. Negative slope of Williamson–Hall plots indicates compressive strain. Particle size of SnO₂ nanostructures is decreases with increases in concentration of fluorine doping. Atomic force microscopy, scanning electron microscopy and transmission electron microscopy studies confirm the formation of ring like porous structures and then hollow tube like growth with increase in the fluorine concentration. Peaks in Raman spectra also indicate strong confinement in SnO₂ particles. Distinct peaks in the PL spectra make the structure suitable for photovoltaic applications.     

Trace analysis in highly concentrated salt solutions of sodium chloride and ammonium fluoride using flame atomic absorption spectrometry

Summary Aqueous solutions of high salt concentration are subjected to direct flame atomic absorption analysis. Blockage of nebulizer and burner is eliminated by employing the dosage scheme washing solution — sample — washing solution effected by means of a specially designed device. The microtrace content of bismuth, zinc and copper in sodium chloride and of copper, lead and iron in ammonium fluoride is determined by the standard addition method. Matrix effects are reduced in the analysis of sodium chloride by the addition of ethanol and in the analysis of ammonium fluoride by pre-heating of sample and washing solution. In order to improve the signal-to-noise ratio, ensemble summation is applied.The following trace element concentrations are determined: 0.5 mg/kg of Cu; 5 mg/kg of Bi and 0.25 mg/kg of Zn in sodium chloride and 0.47 mg/kg of Cu; 0.1 mg/kg of Pb and 3.7 mg/kg of Fe in ammonium fluoride.

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Bestimmung von Spurenelementen in hochkonzentrierten Salzlösungen (NaCl, NH₄F) mittels Flammen-Atom-Absorptions-Analyse

     

辛酸亚锡对氧化锌催化制备丙交酯的影响

用减压蒸馏法合成了丙交酯,在反应的不同时间段加入辛酸亚锡,可使丙交酯最高馏出温度降低至197 ℃。 采用红外光谱表征了丙交酯,测定了反应体系的表面张力和黏度,结果表明,脱自由水后的乳酸、脱自由水后加氧化锌和脱自由水后加氧化锌和辛酸亚锡体系的表面张力分别为38.8、47.0和40.3 N/m;黏度分别为43.1049、59.6774和48.9376 mPa·s。 辛酸亚锡的加入降低了反应体系表观张力和黏度,有利于低聚物结构中酰氧键断裂生成丙交酯。     

A Potassium Based Fluorine Containing Bioactive Glass for Use as a Desensitizing Toothpaste

Potassium releasing bioactive glasses (BAGs) may offer improved relief for dentine hypersensitivity compared to conventional sodium containing BAGs by releasing K⁺ ions for nerve desensitization and occluding dentinal tubules to prevent fluid flow within dentinal tubules. Potassium oxide was substituted for sodium oxide on a molar basis in a fluoride containing BAG used in toothpastes for treating dentine hypersensitivity. The BAG powders were then immersed in an artificial saliva at pH 7 and tris buffer and the pH rise and ion release behavior were characterized by ICP-OES and ISE. The potassium and sodium containing BAGs were characterized by XRD, DSC, FTIR and NMR. Both BAGs presented amorphous diffraction patterns and the glass transition temperature of the potassium glass was higher than that of the sodium glass. The ³¹P MAS-NMR spectra indicated a peak at 2.7 ppm corresponding to apatite and a small peak at −103 ppm indicated crystallization to fluorapatite. Both BAGs dissolved and formed apatite at similar rates, although the dissolution of the potassium glass was slightly slower and it released less fluoride as a result of partial nanocrystallization to fluorapatite upon quenching. The potassium release from the potassium ions could potentially result in nerve deactivation when used in toothpastes.