METHODS: Unstimulated human saliva specimens were collected from 10 patients, and 1.80 ml volumes were divided into three separate 0.60 ml portions, the first and second treated with 0.05 ml of aqueous supernatants derived from dentifrices [1] and [2] respectively, the third serving as an untreated control (dentifrice supernatants were obtained by the treatment of 200 mg of each product with 2.00 ml of doubly-distilled H2O followed by rotamixing and centrifugation). Samples with limited citrate concentrations were pre-treated with a final concentration of 6.00 x 10-4 mol.dm-3 of this agent. 1H NMR analysis was performed at an operating frequency of 600.13 MHz.
RESULTS: Results obtained demonstrated a substantial elevation in Ca2+ ion complexation by salivary citrate, as monitored by 1H NMR-detectable low- and high-frequency shifts of its B and A proton resonances respectively. Resonances arising from 1H NMR-detectable dentifrice components were simultaneously observable in spectra acquired.
CONCLUSION: Our data provide evidence for marked increases in the concentration of Ca2+-citrate complexes in human saliva on treatment with dentifrices containing H2O-reactive phosphosilicates, an observation which may provide valuable mechanistic information regarding the therapeutically-effective delivery of this metal ion by the products tested to active sites involved in the repair of caries-susceptible dentinal tubules.
[1]: Oravive Tooth Revitalising Paste and [2] Denshield Shield Builder, NovaMin Technology, Inc., Alachua, FL 32615 USA.