ANTICARIOGENICITY OF CALCIUM-PHOSPHATE COMPLEXES OF TRYPTIC CASEIN PHOSPHOPEPTIDES IN THE RAT

Casein phosphopeptides (CPP) stabilize calcium phosphate through the f ormation of casein-phosphopeptide amorphous calcium-phosphate complexe s (CPP-CP). The ability of CPP-CP to reduce caries activity was invest igated by use of specific-pathogen-free rats inoculated with Streptoco ccus sobrinus. The animals consumed a defined cariogenic diet free of dairy products Solutions (100 mu L) of the CPP-CP (0.1, 0.2, 0.5, 1.0% w/v) were applied to the animals' molar teeth twice daily. Other grou ps of animals received solutions containing 500 ppm F, the nonphosphor ylated peptides of a casein tryptic digest (0.5% w/v), Or the calcium- phosphate complex of a synthetic octapeptide, -Glu-Ser(P)-Ile-Ser(P)-S er(P)-Ser(P)-Glu-Glu-NHMe, corresponding to the common sequence in the CPP. The CPP-CP significantly reduced caries activity in a dose-respo nse fashion, with 1.0% CPP-CP producing 55% and 46% reductions in smoo th surface and fissure caries activity, respectively, being similar to that of 500 ppm F. The anticariogenic effects of CPP-CP and fluoride were additive, since animals receiving 0.5% CPP-CP plus 500 ppm F had significantly lower caries activity than these animals receiving eithe r CPP-CP or fluoride alone. The tryptic digest of casein with the phos phopeptides selectively removed showed no anticariogenic activity. The synthetic octapeptide-calcium phosphate complex significantly reduced caries activity, confirming that this calcium-phosphate-stabilizing p ortion of the casein phospho-peptides is associated with anticariogeni city. The CPP-CP did not significantly affect the level of S. sobrinus in fissure plaque. The proposed mechanism of anticariogenicity for CP P-CP complexes is that they substantially increase the level of calciu m phosphate in plaque, depressing enamel demineralization and enhancin g remineralization.