The effect of the solution Ca/P ratio on the kinetics of dissolution of octacalcium phosphate at constant pH

Verbeeck, Ronald; Devenyns, J.

doi:10.1016/0022-0248(90)90425-k

Cited by 15 publications

(8 citation statements)

References 31 publications

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“…It could also be due to the formation of The results presented above show that the dissolution of an interfacial layer, as previously proposed for other calcium b-TCP cannot be described by a simple model. The results phosphates (21,27). This explanation is particularly attracindicate that the dissolution of b-TCP particles at low saturative since our results suggest the formation of an interfacial tion is most likely controlled by diffusion processes, even HAp layer on b-TCP particles.…”

Section: Discussionmentioning

confidence: 79%

Kinetics of Dissolution of β-Tricalcium Phosphate

Bohner

Lemaître

Ring

1997

Journal of Colloid and Interface Science

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Section: Discussionmentioning

confidence: 79%

Kinetics of Dissolution of β-Tricalcium Phosphate

Bohner

Lemaître

Ring

1997

Journal of Colloid and Interface Science

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“…[29] Another previously suggested explanation for dissolution rate reduction suggested that changes in the number of active dislocations on crystal surfaces, 1, were involved. [25,30] The rate, assumed to be proportional to 1, would therefore be dependent on the decreasing crystal mass.…”

Section: S ¼ 1às ð7þmentioning

confidence: 99%

Dissolution of Crystallites: Surface Energetic Control and Size Effects

2004

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Traditional understanding of dissolution assumes that the reaction is spontaneous and continues until equilibrium is reached. This paper presents theoretical and experimental data to support a dissolution mechanism that involves the existence of critical conditions for dissolution, in which the reaction is accompanied by the formation of pits and the subsequent displacement of pit steps. The accompanying increase in surface roughness leads to changes in surface energy with losses of crystal mass that are positive rather than negative and the existence of critical dissolution conditions. Critical pits and dissolution steps are verified experimentally and a relationship between the size and rate of displacement of steps is also demonstrated, in which the rate decreases with size and approaches zero at a critical size, r*. These microscopic step dynamics are consistent with the observed size-effects in bulk dissolution, which cannot be explained using traditional dissolution theories. The observed size effects include self-inhibition, in which the dissolution rate decreases with extent of reaction, dissolution suppression, and periodic resumption. These interesting dissolution phenomena are only readily displayed when the sizes of dissolving crystallites fall in the same range as the critical size (i.e., within 50r*). It is interesting to note that natural biominerals and many nanoparticles fall into this category, so that their suspensions can be dynamically stabilized without dissolution in undersaturated supporting media. The current research implies that dissolution kinetics cannot be understood well without appealing to fundamental physical concepts about the energetic control of dissolution steps on a molecular level. A new dissolution model for crystallites is introduced systemically.

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“…Concerning the mechanisms by which OCP precursor converts into apatite crystals, two processes have been postulated (Verbeeck and Devenyns, 1990): in situ hydrolysis (Brown et al, 1979;Nelson and McLean, 1984;Tomazic et al, 1989) and consecutive dissolution-precipitation reactions Johnsson and Nancollas, 1992). The former mechanism is supported by the common observation that OCP hydrolyzates retain the original platy morphology but lose the crystallographic characteristics for OCP.…”

Section: Ocp Hydrolysis and The Effects Of Fluoride On This Processmentioning

confidence: 99%

The Effect of Fluoride On Apatite Structure and Growth

Aoba

1997

Critical Reviews in Oral Biology & Medicine

189

120

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Fluoride participates in many aspects of calcium phosphate formation in vivo and has enormous effects on the process and on the nature and properties of formed mineral. The most well-documented effect of fluoride is that this ion substitutes for a column hydroxyl in the apatite structure, giving rise to a reduction of crystal volume and a concomitant increase in structural stability. In the process of enamel mineralization during amelogenesis (a unique model for the cell-mediated formation of well-crystallized carbonatoapatite), free fluoride ions in the fluid phase are supposed to accelerate the hydrolysis of acidic precursor(s) and increase the driving force for the growth of apatitic mineral. Once fluoride is incorporated into the enamel mineral, the ion likely affects the subsequent mineralization process by reducing the solubility of the mineral and thereby modulating the ionic composition in the fluid surrounding the mineral, and enhancing the matrix protein-mineral interaction. But excess fluoride leads to anomalous enamel formation by retarding tissue maturation. It is worth noting that enameloid/enamel minerals found in vertebrate teeth have a wide range of CO3 and fluoride substitutions. In the evolutionary process from elasmobranch through teleost enameloid to mammalian enamel, the biosystems appear to develop regulatory functions for limiting the fluoridation of the formed mineral, but this development is accompanied by an increase of carbonate substitution or defects in the mineral. In research on the cariostatic effect of fluoride, considerable emphasis is placed on the roles of free fluoride ions (i.e., preventing the dissolution and accelerating the kinetics of remineralization) in the oral fluid bathing tooth mineral. Fluoride also has been used for the treatment of osteoporosis, but much still remains to be learned about maximizing the benefit and minimizing the risk of fluoride when used as a public health measure.

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The effect of the solution Ca/P ratio on the kinetics of dissolution of octacalcium phosphate at constant pH

Cited by 15 publications

References 31 publications

Kinetics of Dissolution of β-Tricalcium Phosphate

Kinetics of Dissolution of β-Tricalcium Phosphate

Dissolution of Crystallites: Surface Energetic Control and Size Effects

The Effect of Fluoride On Apatite Structure and Growth

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