Inhibitory Effects of Zinc Ions on Enamel Demineralisation Kinetics in vitro

2015 ◽  
Vol 49 (6) ◽  
pp. 600-605 ◽  
Author(s):  
Nasrine R. Mohammed ◽  
Richard J.M. Lynch ◽  
Paul Anderson
Keyword(s):  
Linear Relationship ◽  
Real Time ◽  
Zinc Ion ◽  
Ion Concentration ◽  
Zinc Ions ◽  
Percentage Reduction ◽  
Acidic Solutions ◽  
Low Concentrations ◽  
Log Linear

Metal ions including zinc have the ability to influence enamel demineralisation. However, there is a paucity of data regarding reductions in demineralisation effected by zinc ions (Zn2+) in the literature. Therefore the aim was to measure the effects of zinc ion concentration ([Zn2+]) on the real-time in vitro demineralisation of enamel, during exposure to caries-simulating conditions, using scanning microradiography (SMR). Human enamel blocks were fixed in SMR environmental cells, through which acidic solutions (0.1 M acetic acid, pH 4.0) were circulated for periods of 50 h. SMR was used to quantitatively measure continuous mineral mass loss. Subsequently, the effects of sequentially increasing [Zn2+] (0.1-3,565 ppm) in the acidic solutions were measured on the rate of enamel demineralisation. This study demonstrated that Zn2+ even at low concentrations significantly reduces enamel demineralisation. There was a log-linear relationship between the mean percentage reduction in demineralisation and increasing [Zn2+] up to 3,565 ppm, i.e. the change in the overall percentage reduction in demineralisation was greater at lower concentrations than at higher concentrations, with 60% reduction at 36 ppm increasing to 90% at 3,565 ppm. In conclusion, SMR demonstrated the ability of Zn2+ to reduce the rate of enamel demineralisation under real-time in vitro acid conditions simulating dental caries. The results suggest that Zn2+ in the oral fluids could protect against enamel demineralisation during an acidic challenge. The log-linear relationship between [Zn2+] and demineralisation suggests that the reduction in enamel dissolution is limited by the saturation of surface sites on the enamel surface.

Validation of a Real-Time ISE Methodology to Quantify the Influence of Inhibitors of Demineralization Kinetics in vitro Using a Hydroxyapatite Model System

2018 ◽  
Vol 52 (6) ◽  
pp. 598-603
Author(s):  
Wei-Te Huang ◽  
Saroash Shahid ◽  
Paul Anderson
Keyword(s):  
Acetic Acid ◽  
Real Time ◽  
Model System ◽  
Ion Selective Electrodes ◽  
Percentage Reduction ◽  
Inhibitor Concentration ◽  
Rate Of Increase ◽  
Log Linear ◽  
Calcium Loss

The aim was to validate a novel protocol to measure the cariostatic efficacies of demineralization inhibitors by repeating previous SMR (scanning microradiography) studies investigating the dose response of Zn2+ and F– on demineralization kinetics in vitro using real-time Ca2+ ion selective electrodes (ISEs). In this study, Ca2+ release was used as a proxy for the extent of demineralization. Forty-eight hydroxyapatite (HAP) discs were allocated into 16 groups (n = 3) and adding either increasing [Zn2+], or [F–], similar to those used in the previous SMR studies. Each HAP disc was immersed in 50 mL, pH 4.0, buffered acetic acid for 1 h, and real-time ISE methodology was used to monitor the rate of increase in [Ca2+] in the demineralization solution. Next, either zinc acetate or sodium fluoride was added into each demineralization solution accordingly. Then after each [Zn2+] or [F–] addition, the HAP disc was further demineralized for 1 h, and ISE measurements were continued. The percentage reduction in the rate of calcium loss from hydroxyapatite (PRCLHAP) at each [Zn2+] or [F–] was calculated from the decrease in Ca2+ release rate, similar to that used in the previous SMR studies. A log-linear relationship between mean PRCLHAP and inhibitor concentration was found for both Zn2+ and F–, similar to that reported for each ion in the previous SMR studies. In conclusion, real-time Ca2+ ISE systems can be used to measure the cariostatic efficacies of demineralization inhibitors.

scholarly journals Removal of Zinc ions from industrial wastewater with wool fibers

2010 ◽  
Vol 7 (3) ◽  
pp. 1193-1201
Author(s):  
Baghdad Science Journal
Keyword(s):  
Acid Concentration ◽  
Contact Time ◽  
Industrial Wastewater ◽  
Metal Ion ◽  
Low Cost ◽  
Zinc Ion ◽  
Ion Concentration ◽  
Natural Material ◽  
Zinc Ions ◽  
Wool Fibers

In this research, the efficiency of low-cost unmodified wool fibers were used to remove zinc ion from industrial wastewater. Removal of zinc ion was achieved at 99.52% by using simple wool column. The experiment was carried out under varying conditions of (2h) contact time, metal ion concentration (50mg/l), wool fibers quantity to treated water (70g/l), pH(7) & acid concentration (0.05M). The aim of this method is to use a high sensitive, available & cheep natural material which applied successfully for industrial wastewater& synthetic water, where zinc ion concentration was reduced from (14.6mg/l) to (0.07mg/l) & consequently the hazardous effect of contamination was minimized.

scholarly journals Analysis of the Mechanical Properties and Mechanism of Zinc Ion-Contaminated Red Clay

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Jiaming Li ◽  
Shibin Tang ◽  
Xuejun Chen
Keyword(s):  
Point Contact ◽  
Friction Angle ◽  
Zinc Ion ◽  
Material Composition ◽  
Ion Concentration ◽  
Zinc Ions ◽  
Red Clay ◽  
X Ray ◽  
Floc Structure ◽  
The Stability

To study the effects of different concentrations of zinc ions on the mechanical strength, material composition, and microstructure of red clay, a triaxial test, an x-ray diffraction test, an x-ray fluorescence spectrometry test, a scanning electron microscopy test, and a mercury intrusion test were carried out on contaminated soil to investigate the mechanisms of zinc ion-contaminated red clay. The results show that the higher the concentration of zinc ions, the smaller the shear strength and cohesion of the red clay. The internal friction angle is increased first and then decreased. From material composition, zinc ion makes montmorillonite and hemite disappear in red clay. With the increase of zinc ion concentration, quartz semiquantitative increase and kaolinite semiquantitative decrease and the content of SiO2, Fe2O3, and Na2O reduces. Microscopically, the structure of red clay changes from floc structure to granular and aggregate structure after the zinc ions are added, while the contact of the particles is converted to point contact. With the increase of the concentration of zinc ions, the porosity and the fractal dimension of the red clay gradually increase, and the stability of the granular structure is weakened.

scholarly journals Influence of low amounts of zinc or magnesium substitution on ion release and apatite formation of Bioglass 45S5

2020 ◽  
Vol 31 (10) ◽  
Author(s):  
R. Wetzel ◽  
O. Bartzok ◽  
D. S. Brauer
Keyword(s):  
Particle Size ◽  
High Temperature ◽  
Apatite Formation ◽  
Zinc Ions ◽  
Ion Release ◽  
Bioactive Glasses ◽  
Particle Size Range ◽  
Low Concentrations ◽  
High Temperature Processing

Abstract Magnesium and zinc ions play various key roles in the human body, being involved, among others, in skeletal development and wound healing. Zinc is also known to have antimicrobial properties. While low concentrations can stimulate cells in vitro, high concentrations of magnesium or zinc introduced into bioactive glasses significantly reduce glass degradation and ion release and inhibit apatite precipitation. On the other hand, magnesium and zinc ions improve the high temperature processing of bioactive glasses, even when present at low concentrations only. Results here show that by substituting small amounts of Mg or Zn for Ca, ion release remains high enough to allow for apatite precipitation. In addition, magnesium and zinc containing bioactive glasses are shown to be very susceptible to changes in particle size and relative surface area. For a given magnesium or zinc content in the glass, ion release and apatite formation can be enhanced dramatically by reducing the particle size, reaching comparable levels as Bioglass 45S5 of the same particle size range. Taken together, these findings suggest that when introducing these ions into bioactive glasses, ideally low Mg or Zn for Ca substitution as well as small particle sizes are used. This way, bioactive glasses combining good high temperature processing with fast ion release and apatite precipitation can be obtained, providing the potential additional benefit of releasing magnesium or zinc ions in therapeutic concentrations.

TESTS ON INHIBITION OF GERMINATION AND GROWTH OF CORN PLANTS IN THE PRESENCE OF TOXIC SUBSTANCES

2018 ◽  
Vol 32 (1) ◽  
pp. 19-25
Author(s):  
Valeria Mirela Brezoczki ◽  
◽  
Gabriela Maria Filip ◽  
Keyword(s):  
Copper Ions ◽  
Zinc Ion ◽  
Positive Influence ◽  
Toxic Substances ◽  
Zinc Ions ◽  
Ion Concentrations ◽  
Low Concentrations ◽  
Corn Plants ◽  
Germination And Growth ◽  
Nutrient Solutions

The paper presents the results of the germination tests and growth of corn seeds in the lab by exposing them to five concentrations of toxic substances. Nutrient solutions with five different copper sulfate concentrations or zinc sulfate concentration, were used for the tests, respectively 5 mg/L, 15 mg/L, 45 mg/L, 135 mg/L and 405 mg/L and a control variant with no toxic. Each of the variants were carried out in duplicate, and 5 corn seeds were added for each replicate. The exposure periods were 3 and respectively 7 days and after each established period of time, measurements were carried out for the length of the roots and stems. A series of observations, specific for each of the versions, was recorded. The results of the tests for revealed the following highlights: - From the tests we can see how low zinc ion concentrations (5 mg Zn/L and 15 mg Zn/L) have a more positive influence than copper ions on the germination and development of the roots and stems of corn plants. - Zinc ions have a positive influence in low concentrations (5 mg Zn/L) on roots (27,47 %) and stems (5 mg Zn/L and 15 mg Zn/L - 39,05% and 23,41%) during the germination period first 3 days, and a positive influence on stems growth (10 % compared to the control) of copper ions in small concentration (5 mg Cu/L) was registered on germination and growth of stems during the first 3 days.

Kinetics of Various 99mTc-Sn-Pyrophosphate Compounds in the Rat

1977 ◽  
Vol 16 (04) ◽  
pp. 157-162 ◽  
Author(s):  
C. Schümichen ◽  
B. Mackenbrock ◽  
G. Hoffmann
Keyword(s):  
Normal Saline ◽  
Half Life ◽  
Compound A ◽  
Short Half Life ◽  
Low Concentrations ◽  
The Stability ◽  
Kinetics Of ◽  
In Vitro Stability

SummaryThe bone-seeking 99mTc-Sn-pyrophosphate compound (compound A) was diluted both in vitro and in vivo and proved to be unstable both in vitro and in vivo. However, stability was much better in vivo than in vitro and thus the in vitro stability of compound A after dilution in various mediums could be followed up by a consecutive evaluation of the in vivo distribution in the rat. After dilution in neutral normal saline compound A is metastable and after a short half-life it is transformed into the other 99mTc-Sn-pyrophosphate compound A is metastable and after a short half-life in bone but in the kidneys. After dilution in normal saline of low pH and in buffering solutions the stability of compound A is increased. In human plasma compound A is relatively stable but not in plasma water. When compound B is formed in a buffering solution, uptake in the kidneys and excretion in urine is lowered and blood concentration increased.It is assumed that the association of protons to compound A will increase its stability at low concentrations while that to compound B will lead to a strong protein bond in plasma. It is concluded that compound A will not be stable in vivo because of a lack of stability in the extravascular space, and that the protein bond in plasma will be a measure of its in vivo stability.

Sign in / Sign up

Export Citation Format

Share Document