Calcium Fluoride and Phosphate Ion Release From Varnish Formulations

 

Objectives: The objective of this study was to determine the ion release profiles of calcium, phosphate and fluoride ions from microcapsules with ion permeable membranes formulated in resin and rosin based varnish formulations.  Methods: A heterogeneous polymerization technique was utilized to prepare microcapsules containing an aqueous solution of 0.8 M potassium phosphate dibasic, 0.8 M calcium nitrate and 0.8 M sodium fluoride.  Fifteen weight percent of microcapsules were formulated into both a resin and rosin based varnish formulation for a total of six formulations.  Ion release profiles were studied as a function of ion type and time 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:   Ion release profiles were studied as a function of ion type in the varnish formulations.  A table highlighting some of the results is shown below.

Continuous Phase	Ion Release Measured	Initial Conc in microcapsule (M)	Weight % of microcapsules	1 day (ppm)	1 week (ppm)	6 weeks (ppm)	12 weeks (ppm)
Resin	Phosphate	0.8	15	3	4	12	20
Resin	Calcium	0.8	15	1	3	10	15
Resin	Fluoride	0.8	15	0.4	0.6	1	1
Rosin	Phosphate	0.8	15	5	31	70	75
Rosin	Calcium	0.8	15	2	7	24	28
Rosin	Fluoride	0.8	15	0.5	5	19	22

Conclusions: Ion release profiles were generated for varnish formulations containing microencapsulated aqueous solutions that contained biologically available phosphate ions useful in remineralization.  The preparation of varnish formulations with controlled release profiles appears promising based on the variation of ion type encapsulated in the microcapsule fillers.  This work is funded in part by Premier Dental Products Incorporated, GL Materials Research LLC and an NSF University-Industry Partnership grant.