Enhanced enamel F uptake by monocalcium phosphate monohydrate gels.

Application of DCPD-forming solutions has been shown to increase substantially the enamel reactivity toward F. The effectiveness of a variation of this treatment procedure, in which the DCPD-forming solution was replaced by a viscous carboxymethylcellulose gel containing monocalcium phosphate monohydrate (MCPM), was evaluated by use of 12 extracted human molars. The MCPM gel was highly effective in enhancing the F uptake by enamel. The mean F uptakes by teeth treated with MCPM gel, followed by exposure to a F solution, were 3972 (+/- 565), 2383 (+/- 312), and 1751 (+/- 313) ppm, respectively, in the outer 5-, 10-, and 15-microns depths in enamel. These uptakes were 2374, 1273, and 852 ppm more than those of the control teeth. Because the F solution was undersaturated with respect to CaF2, the F incorporated into the enamel was believed to be in apatitic form and not as CaF2. The MCPM gel has advantages over the DCPD-forming solution because (1) much longer gel-tooth contact times can be achieved, and (2) the treatment agent can readily be delivered to specific sites where the tooth needs the protection most.