Ratio of Hydroxyapatite to Calcium Hydrogenphosphate in Some Commercial Dentifrices Containing Hydroxyapatite, Energy-Dispersive X-Ray Microanalysis Study

The ratio of hydroxyapatite (HAP) to calcium hydrogenphosphate (CHP) in 4 commercial dentifrices, which are denoted to contain HAP and CHP, were calculated from the Ca/P molar ratio obtained from energy-dispersive X-ray microanalysis. The ratios of HAP to CHP in the commercial dentifrices were [0.22 to 0.78], [0.23 to 0.77], [0.25 to 0.75], and [0.47 to 0.53], respectively. From our previous in-vitro studies on brushing of human enamel with commercial dentifrices containing HAP and CHP [0.23 to 0.77], and containing CHP but no HAP [0 to 1.00], we suggest that a larger amount of HAP in dentifrice shows a stronger abrasivity, though the HAP is indicated as an active ingredient not but an abrasive.