A New Method of Measuring Hydroxyapatite Dissolution Rate

Forward, G.C.

doi:10.1159/000260243

Cited by 12 publications

(11 citation statements)

References 6 publications

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“…How ever, fluoride present in the buffer solu tion at I ug/ml did reduce the dissolution rate by 20-30%, and this is consistent with numerous reports in the literature [Napper and Smythe, 1966;Forward, 1977;AponteMerced and Feagin, 1979;Grenby and Bull, 1980]. Tung el al., [1981] recently de monstrated exchange of F" for OH" at the surface sites of apatite, and this is consist ent with the observations and mechanism proposed here.…”

Section: Discussionsupporting

confidence: 89%

“…Pellets of the second type were prepared in a simi lar way to that reported by Forward [ 1977] but modi fied by using acetone instead of chloroform as the slurry medium. Mixtures of aqueous apatite (90 wt%) and polyethylene (BDH powder for chromatogra phy) powder ( 10 wt%) or alternatively high-tempera ture apatite (95 wt%) and polyethylene powder (5 wt%) were compressed for 5 min in a 13-mm diam eter KBr die under a vacuum of 0.5 Torr with an ap plied load of 3,000 kg.…”

Section: Preparation O F Apatite Pelletsmentioning

confidence: 99%

“…Previous studies [Napper and Smylhe, 1966;Dedhiya et al, 1974;Forward. 1977;Voegel et al, 1981] have reported de creased initial rates of dissolution of hy droxyapatite in the presence of fluoride ions, strontium ions or various organic molecules in the buffer solution.…”

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confidence: 99%

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Effect of Carbonate and Fluoride on the Dissolution Behaviour of Synthetic Apatites

et al. 1983

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The initial rates of dissolution of synthetic apatites were determined using the rotating disc method. The reactivities of carbonated apatites in acidic media were directly related to their carbonate content. This appeared to be due, in part, to a decrease in the apparent activation energy for dissolution of carbonated apatites. Structurally incorporated fluoride in carbonated apatites at levels up to 1,000 μg/g did not influence the dissolution rates, whereas fluoride at a concentration of 1 μg/ml in the buffer solution reduced the dissolution rates by 20–30%. Apatite dissolution under the experimental conditions was intermediate between transport control and surface chemical control. After 10 min, diffusion processes within the apatite pellets were found to influence the overall dissolution rate.

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Section: Discussionsupporting

confidence: 89%

Section: Preparation O F Apatite Pelletsmentioning

confidence: 99%

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Effect of Carbonate and Fluoride on the Dissolution Behaviour of Synthetic Apatites

et al. 1983

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“…Preparation of HA and Enamel HA powder was prepared, characterised, and compressed into discs as described by Forward [1977).…”

Section: Methodsmentioning

confidence: 99%

Calcium Fluoride and Fluoridated Hydroxyapatite Formation in Relation to the Acid Dissolution Rate of Enamel Mineral

Duke¹,

Forward²

1978

Caries Res

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Hydroxyapatite (HA) discs were treated for 1 min with fluoride solutions of varying concentrations and pH. The calcium fluoride and fluoridated hydroxyapatite (FHA) formed were analysed independently of each other following their separation in molar potassium hydroxide. Only the more intimately associated FHA was found to affect the rate of acid dissolution of HA and its level of formation and the reduction in acid dissolution rate of HA were both found to be linearly related to the logarithm of the ionic fluoride level in the treatment solution following 1 min. pretreatment. The benefit of using acidulated fluoride treatment of enamel is questioned as neutral fluoride treatments of enamel mineral resulted in equivalent protection.

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“…Recently, fluoride dentifrices used in 4 separate anticaries trials Naylor, 1978, 1981;Glass and Shiere, 1978;Naylor and Glass, 1979], in which 3 of the examiners' independent findings had previously shown close agreement, became available for investi gation before the trials began. This study investigates the relationship between the ability of these fluoride dentifrices to form fluoridated hydroxyapatite (FHA) [Duke and Forward, 1978] and reduce the solubil- ity of hydroxyapatite discs [Forward, 1977], and their subsequent performance in anticaries clinical trials.…”

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confidence: 99%

The Relationship between Anticaries Activity of Monofluorophosphate Dentifrices and Their Performances in Laboratory Tests

Duke¹,

Forward²

1985

Caries Res

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The uptake of fluoride by enamel mineral to form alkali-insoluble fluoridated hydroxyapatite (FHA) was measured following pretreatment of hydroxyapatite powder with soluble extracts of 8 sodium monofluorophosphate dentifrices and 1 control (non-fluoride) dentifrice under conditions relevant to normal dentifrice usage. The ability of slurries of these toothpastes to reduce the acid dissolution rate of compressed discs of hydroxyapatite was also measured in the laboratory employing similar pretreatment conditions. These 2 laboratory measurements for each dentifrice were compared with their anticaries clinical efficacies calculated as the percentage reduction in the decayed and filled surfaces (DFS) increment when compared with the corresponding control dentifrice treatment. The DFS increments had been previously determined in 4 separate, double-blind clinical trials lasting 30–36 months, by examiners who had demonstrated close agreement between their independent findings. A Spearman product-moment correlation coefficient, γ, of 0.89 was observed (p < 0.01) with results from the FHA technique and a correlation, r, of 0.95 (p < 0.001) with results from the reduction in dissolution. Using the Kendall rank correlation method, a coefficient, τ, of 0.67 was obtained (p < 0.02) with the FHA technique, and of 0.81 (p < 0.002) with the disc dissolution technique. The correlation coefficients suggested that the measurement of these 2 parameters, when carried out under conditions similar to those experienced at the tooth surface during normal brushing procedure, is of value in predicting the anticaries efficacy of dentifrices.

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A New Method of Measuring Hydroxyapatite Dissolution Rate

Cited by 12 publications

References 6 publications

Effect of Carbonate and Fluoride on the Dissolution Behaviour of Synthetic Apatites

Effect of Carbonate and Fluoride on the Dissolution Behaviour of Synthetic Apatites

Calcium Fluoride and Fluoridated Hydroxyapatite Formation in Relation to the Acid Dissolution Rate of Enamel Mineral

The Relationship between Anticaries Activity of Monofluorophosphate Dentifrices and Their Performances in Laboratory Tests

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