A Mineralization Adsorption and Mobility Study of Hydroxyapatite Surfaces in the Presence of Zinc and Magnesium Ions

Fuierer, Tristan A; Lore, M.; Puckett, Scott A.; Nancollas, G.H.

doi:10.1021/la00024a054

Cited by 71 publications

(48 citation statements)

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“…In general, the SMR study demonstrated that enamel demineralisation rates were increasingly reduced with successive increases in [Zn 2+ ] in the acid solutions. The rapid and substantial ( ∼ 60%) reduction in PRML enamel between 0.1 and 36 ppm [Zn 2+ ] could be explained by the almost instantaneous occupancy of the abundant PO 4 3-binding sites and/or 'active' dissolution sites by zinc ions [Fuierer et al, 1994]. As these sites become occupied, the rate of demineralisation is effectively reduced.…”

Section: Discussionmentioning

confidence: 99%

“…The apparent change in gradients in the log-linear curve indicates that the mechanistic behaviour of zinc is concentration dependent, and that more than one mechanism is probably occurring between increasing [Zn 2+ ] and the tooth enamel surface under acid conditions. Mohammed et al [2014] previously suggested that zinc acts at PO 4 3-sites in its mechanism in reducing enamel mineral loss, and forms an α-hopeite-like phase once surface adsorption is completed [Fuierer et al, 1994;Davey et al, 1997].…”

Section: Discussionmentioning

confidence: 99%

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Inhibitory Effects of Zinc Ions on Enamel Demineralisation Kinetics in vitro

Mohammed

Lynch²,

Anderson³

2015

Caries Res

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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.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Inhibitory Effects of Zinc Ions on Enamel Demineralisation Kinetics in vitro

Mohammed

Lynch²,

Anderson³

2015

Caries Res

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“…The apparent stabilization of ACP may be because of the binding of Mg 2+ to newly formed nuclei, not only preventing these from reaching a critical growth size and subsequent Ostwald maturation, but also leading to redissolution [13]. The equilibrium adsorption of Zn 2+ on HAP suggests that the formation of zinc phosphate (hopeite) dominates the surface properties and determines the degree of inhibition of HAP crystal growth [14]. At neutral pH, anionic organic macromolecules such as proteins show a considerably greater influence on HAP crystallization than do positive or neutral species, suggesting that they bind to the CaP nanoclusters; this is especially the case for proteins with a hydrophilic carboxylate head that can significantly shorten the induction time of OCP [15] or HAP [16,17], and promote the formation of the corresponding crystals.…”

Section: Nucleation and Growth Of Calcium Orthophosphate Crystals Fromentioning

confidence: 99%

Dynamics of crystallization and dissolution of calcium orthophosphates at the near-molecular level

Wang

et al. 2011

Chin. Sci. Bull.

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Although extensive investigations of biogenic and geological calcium phosphate crystallization/dissolution and their phase transformations have been performed, the mechanisms of crystallization and dissolution of sparingly soluble calcium phosphates in geological settings have not been completely determined at the near-molecular level. In particular, an understanding of the physical-chemical processes at the earliest nucleation stage and the subsequent crystal surface dynamics in soil solutions is lacking. This review focuses on the earliest events in homo/heterogeneous nucleation from an initial supersaturated solution phase, the subsequent growth of calcium phosphate phases, and the relevant influences of the presence of additional inorganic and organic molecules in both geological and biological settings. These studies have implications for the understanding of the complex processes of calcium phosphate transformations in soils, and provide possible physical-chemical mechanisms for the biogeochemical behavior of phosphorus at the near-molecular level. calcium orthophosphates, crystallization, dissolution, AFM Citation:Wang L J, Lu J W, Xu F S, et al. Dynamics of crystallization and dissolution of calcium orthophosphates at the near-molecular level.

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“…Fewer works have been undertaken on other potentially hazardous elements, but the precipitation of metal phosphate compounds (e.g., Ni, Zn, Cd) was suggested from laboratory and field studies (Valsami-Jones et al, 1998;Greman et al, 2001;Seaman et al, 2001), although these compounds are more soluble than Pb-phosphates. When Zn 2+ is added to AP suspension, laboratory experiments showed that this element reacts with AP or the solute species resulting from its dissolution (Xu and Schwartz, 1994;Peaudecerf, 2002) (Fuierer et al, 1994;Xu and Schwartz, 1994) and, in addition, on the proton activity since the dissolution rate of AP is pH-dependent (section 2.1.3, and Valsami-Jones et al, 1998). The formation of Zn-libethenite can be excluded in our case because this mineral was formed in Misra and Bowen's experiments (1981) for Zn concentrations ranging from 3250 to 26000 mg L -1 , in excess by three to four orders of magnitude of Zn concentrations measured in the pore waters (5 to 30 mg L -1 ).…”

Section: Effect Of Amendments On Zn Speciationmentioning

confidence: 99%

The effect of phytostabilization on Zn speciation in a dredged contaminated sediment using scanning electron microscopy, X-ray fluorescence, EXAFS spectroscopy, and principal components analysis

Panfili

Manceau

Sarret

et al. 2005

Geochimica et Cosmochimica Acta

122

129

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Running Title: Effect of phytostabilzation on Zn speciation in dredged sediment 2 ABSTRACTThe maintenance of waterways generates large amounts of dredged sediments, which are deposited on adjacent land surfaces. These sediments are often rich in metal contaminants and present a risk to the local environment. Understanding how the metals are immobilized at the molecular level is critical for formulating effective metal containment strategies, such as phytoremediation. In the present work, the mineralogical transformations of Zn Seven Zn species were identified at the micrometer-scale : sphalerite, gahnite, franklinite, Zncontaining ferrihydrite and phosphate, (Zn-Al)-hydrotalcite, and Zn-substituted, kerolite-like, trioctahedral phyllosilicate. Bulk fractions of each species were quantified by LSF of the powder EXAFS spectra to linear combinations of the identified Zn species spectra.In the untreated and unvegetated sediment, Zn was distributed as ~50 % (mole ratio of total Zn) sphalerite, ~40 % Zn-ferrihydrite, and ~10-20 % (Zn-Al)-hydrotalcite plus Znphyllosilicate. In unvegetated but amended sediments (AP and TS), ZnS and Zn-ferrihydrite each decreased by 10 to 20 % and were replaced by Zn-phosphate (~30-40 %). In the presence of plants, ZnS was almost completely dissolved and the released Zn bound to phosphate (~40-60 %) and to Zn phyllosilicate plus (Zn,Al)-hydrotalcite (~20-40 %). Neither the plant species 3 nor the co-addition of mineral amendment affected the Zn speciation in the vegetated sediment.The sediment pore waters were supersaturated with respect to Zn-containing trioctahedral phyllosilicate, near-saturation with respect to Zn-phosphate, and strongly undersaturated with respect to (Zn,Al)-hydrotalcite. Therefore, the formation of (Zn,Al)-hydrotalcite in slightly alkaline conditions ought to result from heterogenous precipitation on mineral surface. 4

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A Mineralization Adsorption and Mobility Study of Hydroxyapatite Surfaces in the Presence of Zinc and Magnesium Ions

Cited by 71 publications

References 0 publications

Inhibitory Effects of Zinc Ions on Enamel Demineralisation Kinetics in vitro

Inhibitory Effects of Zinc Ions on Enamel Demineralisation Kinetics in vitro

Dynamics of crystallization and dissolution of calcium orthophosphates at the near-molecular level

The effect of phytostabilization on Zn speciation in a dredged contaminated sediment using scanning electron microscopy, X-ray fluorescence, EXAFS spectroscopy, and principal components analysis

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