In an abstract, Rugg-Gunn & Boteva (1997) compared enamel fluoride
uptake in vivo when enamel samples mounted in intra-oral appliances
were worn in the mouth and exposed four times daily for 5 days to
fluoridated milk or water. Uptake was greater for fluoridated milk when
it was swallowed after rinsing, compared with rinsing alone or fluoride
in water. Similar results were found with sound or demineralised surfaces.
This preliminary result suggests the importance of the indirect
effect of fluoride after absorption and re-secretion in saliva.