Objectives: The objective of this study was to determine the capability of releasing biologically available calcium and phosphate ions from aqueous solutions contained in microcapsules formulated in toothpaste. Methods: A heterogeneous polymerization technique was utilized to prepare microcapsules containing an aqueous solution of 5 M potassium phosphate dibasic and 3 M calcium nitrate. Five weight percent of microcapsules were formulated into a commercially available toothpaste formulation. Ion release was studied as a function of ion type. The amount of available fluoride was also measured. The stability of the toothpaste was measured for 12 weeks. Phosphate ion detection was performed by the molybdenum blue method and reported as ppm of phosphate ion released per gram of formulation. Calcium and fluoride ion release measurements were performed using ion specific electrodes. Results: One gram of toothpaste formulated with either phosphate or calcium containing microcapsules was placed in 10 mL of nanopure water and brushed for 1 minute. An aliquot was removed after brushing and was analyzed for calcium, phosphate and fluoride ions. Ion release measurements were studied as a function of ion type in the varnish formulations. A table highlighting some of the results is shown below.
Ion Release
| No Microcapsules (ppm) | 5 wt% of 3M Ca(NO3)2 microcapsules (ppm) | 5 wt% of 5M K2HPO4 microcapsules (ppm) |
Fluoride | 66 | 15 | 65 |
Calcium | 0.7 | 210 | 0.5 |
Phosphate | 1.5 | 0.6 | 1020 |
Conclusions: Using mechanical agitation of a toothbrush, phosphate and calcium ions were released in significant concentrations from microcapsules formulated in toothpaste. The preparation of a toothpaste formulation with significant bioavailable levels of calcium, phosphate and fluoride ions should provide for enhanced remineralization. This work is funded by Premier Dental Products Incorporated.