IADR Abstract Archives
Fluorapatite and CaF2 Formation in Low Concentration Fluoride-Calcium-Phosphate Complex Solutions
Objectives: : The present study investigated the effects of a fluoride (1500 ppm F)-calcium-phosphate complex solution composition on the nature and amount of precipitate formed when the pH was raised by an activation solution (AS). The results could assist in developing a self-applied dentin desensitization or remineralization treatments.
Methods: The FCP solution contained 78.9mM NaF (1500 ppm F), 0.1M H3PO4, and 0.2M (FCP1) or 1.0M (FCP2) CaCl2. The AS contained 78.9mM NaF and 0.1M (AS1) or 0.5M (AS2) K2HPO4. 0.75mL of the FCP solution was added to 0.75ml of the AS and mixed well. The precipitate was washed with distilled water, dried, weighed, and analyzed by powder X-ray diffraction (XRD) for phase composition.
Results: The amount of precipitates formed in the four groups were (1) (6.7±0.3) mg (mean ± s.d.; n=5) in AS1+FCP1, (2) (5.9±1.5) mg in AS1+FCP2, (3) (20.4±0.7) mg in AS2+FCP1, and (4) (47.6±1.1) mg in AS2+FCP2. Two-way ANOVA indicated that the amounts of precipitation formed were affected (p<0.05) by both the P concentration in the AS and the Ca concentration in the FCP. Group (4) produced significantly greater precipitate (p<0.05) than group (3), which was greater than those in groups (1) and (2). XRD analyses showed the phases present in the precipitates in the four groups were (1) CaF2>>>fluorapatite (FA), (2) CaF2>FA, (3) FA>CaF2, and (4) FA>>CaF2. The higher calcium and phosphate concentrations in the combined solution in group (4) led to higher FA formation compared to CaF2.
Conclusions: The results show that large amounts of CaF2 and FA precipitation can be formed from a small volume of the AS+FCP solution, and that the relative amounts of CaF2 and FA in the precipitation are controllable. These compositions are useful for formulating more effective self-applied dentin desensitization treatments.
Methods: The FCP solution contained 78.9mM NaF (1500 ppm F), 0.1M H3PO4, and 0.2M (FCP1) or 1.0M (FCP2) CaCl2. The AS contained 78.9mM NaF and 0.1M (AS1) or 0.5M (AS2) K2HPO4. 0.75mL of the FCP solution was added to 0.75ml of the AS and mixed well. The precipitate was washed with distilled water, dried, weighed, and analyzed by powder X-ray diffraction (XRD) for phase composition.
Results: The amount of precipitates formed in the four groups were (1) (6.7±0.3) mg (mean ± s.d.; n=5) in AS1+FCP1, (2) (5.9±1.5) mg in AS1+FCP2, (3) (20.4±0.7) mg in AS2+FCP1, and (4) (47.6±1.1) mg in AS2+FCP2. Two-way ANOVA indicated that the amounts of precipitation formed were affected (p<0.05) by both the P concentration in the AS and the Ca concentration in the FCP. Group (4) produced significantly greater precipitate (p<0.05) than group (3), which was greater than those in groups (1) and (2). XRD analyses showed the phases present in the precipitates in the four groups were (1) CaF2>>>fluorapatite (FA), (2) CaF2>FA, (3) FA>CaF2, and (4) FA>>CaF2. The higher calcium and phosphate concentrations in the combined solution in group (4) led to higher FA formation compared to CaF2.
Conclusions: The results show that large amounts of CaF2 and FA precipitation can be formed from a small volume of the AS+FCP solution, and that the relative amounts of CaF2 and FA in the precipitation are controllable. These compositions are useful for formulating more effective self-applied dentin desensitization treatments.