Enhanced fluoride uptake from mouthrinses

It has been shown in laboratory and animal studies that tooth enamel becomes considerably more reactive toward low levels of fluoride after receiving pre-treatment which forms dicalcium phosphate dihydrate (DCPD) in the enamel as an intermediate. This in vitro study was undertaken to determine the effect on human enamel fluoride uptake of incorporating DCPD-forming rinses into a conventional fluoride rinsing program. In one group, enamel samples received a one-minute rinse with 0.2% NaF each day for 20 days. Samples in the second group were treated identically, except that they were also given a one-minute DCPD-forming rinse prior to the first, sixth, eleventh, and sixteenth fluoride rinses. At the end of the rinsing program, all samples were washed in 1 M KOH to remove labile fluorides. The enamel biopsy data showed that the fluoride uptake resulting from 0.2% NaF alone was not statistically significant, whereas uptake produced by the DCPD-forming plus NaF rinses was significant. The results suggest that the DCPD-forming rinse may improve the efficacy of fluoride rinse programs.

Reactions of powdered human enamel and fluoride solutions with and without intermediate CaHPO4 x 2H2O formation

Powdered human enamel treated for three minutes each with a CaHPO4 x 2H2O forming solution and a fluoride solution, and then suspended in "synthetic saliva" for 72 hours acquired a large amount of apatitic fluoride. This apatitic fluoride appears to form after the fluoride treatment.

Effects of some staining agents on dentin apposition in young rabbits

Alizarin red S, trypan blue, chlortetracycline, and 45Ca were administered to young rabbits that received multiple injections of lead acetate as marker. Inhibiting effects of these agents on dentin apposition were studied. No evidence of toxicity of chlortetracycline or 45Ca was detected. Alizarin at 100 mg/kg reduced the rate of dentin apposition, and 150 mg/kg caused severe retardation. Trypan blue at 50 to 100 mglkg showed no adverse effects, but 350 mglkg arrested dentinogenesis completely.