Calcium Release from Chewable Calcium Supplements in a Simulated Chewing

Objectives: A calcium rinse before fluoride rinse has been shown to enhance the retention of fluoride in dental biofilm and reduce dental demineralization. Other calcium sources, such as chewing calcium supplements, could be used before a fluoride rinse, but the amount of calcium released from chewing these supplements is unknown. Here we tested the release of calcium from different chewable calcium supplements to artificial saliva in a simulated chewing in vitro.
Methods: Five calcium supplements (n=3 from different lots), presented as chewable chocolate, tablet or gummies, were tested; two of them were calcium carbonate-based and three contained tricalcium phosphate. To simulate chewing and calcium release to stimulated saliva in the oral cavity, one piece of each calcium supplement was cut into ~5 x 5 mm fragments and ground with the aid of a mortar and pestle in 6 mL of artificial saliva (containing 1.5 mM Ca, pH 7.0) for 30 s. The resulting mixture was centrifuged and the soluble calcium concentration determined in the supernatant using the Arsenazo III colorimetric reaction. The pH of the supernatant was also determined.
Results: The pH for the tricalcium phosphate gummies ranged from 4.2±0.04 to 4.6±0.03, and for the calcium carbonate-based products from 6.3±0.01 to 7.5±0.04. All supplements released calcium and increased the final concentration in the supernatant when compared to the baseline concentration in the artificial saliva; higher calcium concentrations (ranging from 18.1±1.1 to 30.9±2.6 mM Ca) were reached with the tricalcium phosphate-based gummies than with the calcium carbonate-based products (6.1±0.7 and 9.8±1.8 mM Ca).
Conclusions: The results suggest that chewable calcium supplements can significantly enhance calcium concentration in saliva and therefore could be used in approaches to increase the effect of fluoride in the mouth.