Development of P<sub>2</sub>O<sub>5</sub> Insolubility in Phosphatic Mixtures The Formation of Fluorapatite as Its Causein

Macintire, W. H.; Hardin, L. J.; Oldham, F. D.; Hammond, J. W.

doi:10.1021/ie50331a008

Cited by 9 publications

(5 citation statements)

References 6 publications

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“…No development of citrate-insoluble P2O5 occurred in the admixture of calcine with the monocalcium phosphate at the 1:1.78 ratio. As noted, however, the monocalcium mixtures of Table III were fluoride-free, and citrate insolubility attributable to formation of fluorapatite (16) was, therefore, not involved. P2O5 Transitions in Slurry Mixtures o£ Ammonium Phosphate and CaCOa-MgO Calcine…”

Section: Phosphatesmentioning

confidence: 83%

Behavior of a New Source of Available Magnesium for Phosphatic Fertilizers

Macintire¹,

Hardin²,

Oldham³

1938

Ind. Eng. Chem.

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Section: Phosphatesmentioning

confidence: 83%

Behavior of a New Source of Available Magnesium for Phosphatic Fertilizers

Macintire¹,

Hardin²,

Oldham³

1938

Ind. Eng. Chem.

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“…Just as Ca3(PO4)2 will react with solution of CaF2 (24,25) to form by addition reaction the relatively insoluble fluorapatite and just as calcium hydroxyapatite will react with soluble fluorides to form by exchange reaction fluoroapatite 3Ca3(PO4) -CaF2 (26), so the possibility exists for similar addition or exchange reactions between the constituent ions and molecules of enamel and other ions, such as Pb, oxalate, SO4, etc. Such reactions might produce compounds less soluble than the original, such as a highly insoluble lead hydroxyapatite, the existence of which has already been shown (27).…”

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confidence: 99%

The Effects of Various Ions on Enamel Solubility

Buonocore

Bibby

1945

J Dent Res

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Several reports in the literature indicate that the solubility of enamel in acids can be changed by the action of various ions. Miller (1) using silver nitrate was unable to show retardation in enamel decalcification. The research work of Rickert (2) contradicted this and led him to believe that increased resistance to decalcification of silver nitrate-treated enamel was due to the clogging of tooth substance with reduced silver which prevented the penetration of acids. Hill and Arnold (3) studied the effects of silver nitrate on powdered enamel and found that after treatment, the solubility of enamel was significantly reduced. Difference in enamel solubility in acetate and maleate buffers was attributed by Benedict and Kanthak (4) to the formation of calcium maleate which acted as a protective coating over the enamel particles. Volker (5) and Bibby (6) investigated the effect of fluorides on enamel and concluded that the fluorine ion produced marked reduction in solubility. Because little or no consideration has been given to the effects of other ions on the solubility of enamel, it seemed to us worthwhile to investigate the matter.The choice of the ions used in the experiments was determined by a consideration of the mechanisms whereby the phenomenon of reduced solubility might occur. In order to better understand these, an examination of the chemical nature of enamel is necessary. This will be limited to facts relevant to the adequate understanding of certain assumptions which are made in this paper.Tooth enamel is a crystalline substance showing a characteristic x-ray diffraction pattern. Moreover, this pattern is practically identical with that given by bone, dentin and certain synthetic or natural inorganic materials, such as fluorapatite. On the basis of these x-ray findings these substances have been included in the general class of apatites. It should be remembered that this apatite classification refers only to a particular atomic pattern or arrangement in the crystal lattice and not to any constancy of chemical composition. For instance, McConnell (7,8) has pointed out that a large number of substitutions are possible in the general apatite pattern. If X10(ZO4)6. (F20H2C12) represents the general formula for the apatites, then X may be calcium, lead, manganese, potassium, strontium and cesium or in lesser amounts yttrium, lanthanum, titanium, iron, aluminum and magnesium; Z may be chromium, phosphorous, arsenic, vanadium, silicon, and carbon. Further evidence of the complex and variable nature of the apatites is obtained from the work of Eisenberger, Lehrman and Turner (9). In their critical review of the literature on the system

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“…Fluorine has been found deposited posteruptively by the rat in molar enamel but not in dentin (4). In vitro experiments show powdered enamel and dentin (5, 6), as well as bone tissue (7) to have the property, in common with pure mineral phosphates (8,9,10), of adsorbing fluoride.The above in vivo experiments (1, 2, 3) are interesting from several aspects. First: They indicate that dentin and enamel may be modified chemically during post-eruptive tooth life or after calcification has been completed.…”

mentioning

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“…The observed adsorption of fluorine by mineral phosphates (8,9,10), bone (7), and dental tissues (5, 6) is only presumptive evidence that exposed enamel in the oral cavity has a similar capacity. In general, the fluorosed phosphates and bone and dental tissue resulting from these reactions show reduced acid solubility (6, 9 andunpublished datafromthis laboratory).…”

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Observations on Induced Caries in Rats

McClure

1943

J Dent Res

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The post-eruptive increase of fluorine in dentin and enamel has been observed in rats (1, 2) and in an adult dog (3). Fluorine has been found deposited posteruptively by the rat in molar enamel but not in dentin (4). In vitro experiments show powdered enamel and dentin (5, 6), as well as bone tissue (7) to have the property, in common with pure mineral phosphates (8,9,10), of adsorbing fluoride.The above in vivo experiments (1, 2, 3) are interesting from several aspects. First: They indicate that dentin and enamel may be modified chemically during post-eruptive tooth life or after calcification has been completed. Second: Although fluorine was ingested in quantities varying from 10 ppm. to 125 ppm. by rats (1) a relatively constant proportion between fluorine retained by the enamel and fluorine retained by the dentin was maintained, i.e., about 3.5 to 4.0 times as much fluorine was found present in the dentin as in the enamel. This would seem to be due to an orderly systemic process. It advances the hypothesis that similar chemico-physical properties may be attached to both adult enamel and to adult dentin. Third: The retention of ingested fluoride by teeth post-eruptively raises the question of the relation of such secondary fluorine deposits to caries resistance.Epidemiological evidence has demonstrated the caries inhibitory properties of fluoride in water ingested during the period of tooth calcification (11,12,13,14). An important point to emphasize in these studies (13,14) is the distinction made between certain minimum quantities of fluorine which seemingly improve the dental tissue, and somewhat higher levels, which produce the hypocalcification or hypocalcification and hypoplasia known as endemic dental fluorosis (mottled enamel). On the basis of physiological effects, it also seems necessary to differentiate between at least two forms of dental tissue fluoride, i.e., fluorine acquired during the formative life of the tooth (primary fluoride) and fluorine acquired during adult or post-eruptive tooth life (secondary fluoride). There is the possibility of a third form of fluoride, i.e., fluorine acquired by the exposed oral enamel through surface adsorption (adsorbed secondary enamel fluoride) (4).

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Development of P₂O₅ Insolubility in Phosphatic Mixtures The Formation of Fluorapatite as Its Causein

Cited by 9 publications

References 6 publications

Behavior of a New Source of Available Magnesium for Phosphatic Fertilizers

Behavior of a New Source of Available Magnesium for Phosphatic Fertilizers

The Effects of Various Ions on Enamel Solubility

Observations on Induced Caries in Rats

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Development of P2O5 Insolubility in Phosphatic Mixtures The Formation of Fluorapatite as Its Causein

Cited by 9 publications

References 6 publications

Behavior of a New Source of Available Magnesium for Phosphatic Fertilizers

Behavior of a New Source of Available Magnesium for Phosphatic Fertilizers

The Effects of Various Ions on Enamel Solubility

Observations on Induced Caries in Rats

Contact Info

Product

Resources

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Development of P₂O₅ Insolubility in Phosphatic Mixtures The Formation of Fluorapatite as Its Causein