Hydrogen Bonding in Apatitic Calcium Phosphates

Winand, L.; Dallemagne, M. J.; Duyckaerts, G.

doi:10.1038/190164a0

Cited by 39 publications

(24 citation statements)

References 4 publications

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“…1 (19) for hydroxyapatite are given in (58,61). This is in accord with the low Ca/P ratios of early tooth and bone mineral (62), and the concomitant tendency to form pyrophosphate when heated (63,64 …”

supporting

confidence: 50%

Apatites :

Brown¹

1971

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supporting

confidence: 50%

Apatites :

Brown¹

1971

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“…No attempt was made to interpret the resuits in light of the various proposed formulas for the composition of defect apatites [4][5][6][7][8][9] since the object of the separation technique was to isolate the precipitates, unchanged, from well-characterized solutions. The precipitates, which were filtered quickly and unwashed, undoubtedly contain small amounts of adsorbed impurities.…”

Section: Discussionmentioning

confidence: 99%

“…Meyer at the above address. where0< • < lor0<-x <_2 which resulted from a series of studies involving indirect chemical measurements and/or spectroscopic methods [5][6][7][8][9][10][11][12]. These formulas suggest that the charge imbalance due to the calcium defect is neutralized by the addition of a hydrogen ion coupled with the removal of a hydroxide ion from the lattice.…”

Section: Introductionmentioning

confidence: 99%

Hydroxyl content of solution-precipitated calcium phosphates

Meyer

1979

Calcif Tissue Int

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A method is described for determination of the titratable hydroxide ion in calcium phosphate precipitates. The procedure requires accurate analysis of the other titratable species in the crystal lattice but is unaffected by the presence of other lattice constituents or impurities. The method was applied to precipitates that had been previously analyzed by solution thermodynamic techniques, and the results were consistent with the earlier observations. The hydroxide content of the precipitates increased with crystal maturity and with increasing pH of the precipitation medium. The hydroxide content of the amorphous phase and the immediate postamorphous-crystalline transformation phase was shown to be nearly zero. After 3 to 4 days' maturation, the hydroxide content of precipitates prepared at pH values of 7, 8, and 9 was shown to increase to approximately 23, 40, 56% of that required for pure hydroxyapatite.

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“…Such variations include missing ions, particularly calcium (Posner and Perloff, 1957;Winand et al, 1961) and hydroxyl (Young and Spooner, 1969;Myrberg, 1968). Hydroxyl was reported as being 20-30% lower in enamel compared with stoichiometric apatite.…”

Section: Introductionmentioning

confidence: 99%

The Chemistry of Enamel Caries

Robinson

Shore

Brookes

et al. 2000

Critical Reviews in Oral Biology & Medicine

321

316

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The chemical changes which occur during the process of carious destruction of enamel are complex due to a number of factors. First, substituted hydroxyapatite, the main component of dental enamel, can behave in a very complex manner during dissolution. This is due not only to its ability to accept substituent ions but also to the wide range of calcium phosphate species which can form following dissolution. In addition, the composition, i.e., the extent of substitution, changes throughout enamel in the direction of carious attack, i.e., from surface to interior. Both surface and positively birefringent zones of the lesion clearly illustrate that carious destruction is not simple dissolution. Selective dissolution of soluble minerals occurs, and there is the probability of reprecipitation. The role of fluoride here is crucial in that not only does it protect enamel per se but also its presence in solution means that rather insoluble fluoridated species can form very easily, encouraging redeposition. The role of organic material clearly needs further investigation, but there is the real possibility of both inhibition of repair and facilitation of redeposition. For the future, delivering fluoride deep into the lesion would appear to offer the prospect of improved repair. This would entail a delivery vehicle which solved the problem of fluoride uptake by apatite at the tooth surface. Elucidation of the role of organic material may also reveal putative mechanisms for encouraging repair and/or protecting the enamel mineral.

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Hydrogen Bonding in Apatitic Calcium Phosphates

Cited by 39 publications

References 4 publications

Apatites :

Apatites :

Hydroxyl content of solution-precipitated calcium phosphates

The Chemistry of Enamel Caries

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