830 Temperature and Counterion Effect on Ion Release from Ion-Permeable Microcapsules

Friday, March 23, 2012: 2 p.m. - 3:15 p.m.
Presentation Type: Poster Session
M.Q. SCHMIDT1, T. GREVING2, W. MCHALE3, M.A. LATTA4, and S. GROSS2, 1Chemistry, Creighton University, Omaha, NE, 2Creighton University, Omaha, NE, 3Product Development, Premier Dental Products Company, Plymouth Meeting, PA, 4School of Dentistry, Creighton University, Omaha, NE

Objectives: The objective of this study was to measure the release of calcium and phosphate ions from microcapsules with ion permeable membranes as a function of counterion, concentration and temperature.  Methods: A heterogeneous polymerization technique was utilized to prepare a series of microcapsules based on an ethylene glycol based polyurethane containing different aqueous solutions of potassium phosphate dibasic, sodium phosphate dibasic, potassium phosphate monobasic, calcium nitrate, calcium chloride and calcium acetate.  Ion release profiles were studied as a function of initial ion concentration within the microcapsule, ion type and counterion type, and temperature. Phosphate ion detection was performed by the molybdenum blue method.  Calcium ion release measurements were performed using ion specific electrodes.  Results:   Ion release profiles were studied as a function of initial ion concentration in the microcapsule, ion and counterion identity and temperature.  A table highlighting some of the results is shown below.

Salt

Identity

Ion Release Measured

Initial Concentration in microcapsule (M)

0.1 hour (ppm)

20 hours

(ppm)

48 hours

(ppm)

72 hours

(ppm)

Calcium nitrate

Calcium

1

0

4

31

81

Calcium chloride

Calcium

1

2

11

15

24

Calcium acetate

Calcium

1

3

6

18

36

Potassium phosphate dibasic

Phosphate

6

8

600

1982

2028

Potassium phosphate dibasic

Phosphate

3

2

214

897

1392

Conclusions: Ion release profiles were generated for microencapsulated aqueous solutions that contained biologically available ions useful in remineralization.  The preparation of microcapsules with controlled release profiles appears promising based on counterion selection and concentration.  This work is funded in part by Premier Dental Products Incorporated, GL Materials Research LLC and an NSF University-Industry Partnership grant.

This abstract is based on research that was funded entirely or partially by an outside source: NSF/EPSCoR University-Industry Partnership Grant

Keywords: Dental materials, Mineralization and Remineralization