INCORPORATION OF CASEINOGLYCOMACROPEPTIDE AND CASEINOPHOSPHOPEPTIDE INTO THE SALIVARY PELLICLE INHIBITS ADHERENCE OF MUTANS STREPTOCOCCI

The protective effects of milk and milk products against dental caries have been demonstrated in many animal studies. We have shown that thi s effect was mediated by micellar casein or caseinopeptide derivatives . A reduction in the Streptococcus sobrinus population in the oral mic robiota of animals fed diets supplemented with these milk components w as consistently observed. A possible explanation for these findings is that milk components are incorporated into the salivary pellicle, the reby reducing the adherence of S. sobrinus. This hypothesis was tested in vitro by the incubation of bovine enamel discs with unstimulated s aliva. The resulting pellicle was washed and incubated with caseinogly comacropeptide (CGMP) and/or caseinophosphopeptide (CPP) labeled with 17- and 12-nm gold particles. All samples were prepared for electron m icroscopy by high-pressure freezing followed by freeze-substitution. I t was demonstrated by high-resolution scanning electron microscopy wit h back-scattered electron imaging, as well as by transmission electron microscopy, that both peptides were incorporated into the pellicle in exchange for albumin, confirming previous findings. This protein was identified with a mouse anti-human serum albumin followed by goat anti -mouse IgG labeled with 25-nm gold particles. Incorporation of CGMP an d/or CPP into salivary pellicles reduced the adherence of both S. sobr inus and S. mutans significantly. It is suggested that the calcium- an d phosphate-rich micellar casein or caseinopeptides are incorporated i nto the pellicle. The resulting ecological shifts, together with the i ncreased remineralization potential of this biofilm, may explain its m odified cariogenic potential.