Distribution of fluoride in gingival fluid and dental plaque of dogs.

Abstract The possibility of gingival fluid being a source of plaque fluoride has been investigated in dogs anaesthetised for veterinary examination and dental treatment. The radionuclide 18 F was injected intravenously and the tracer was detected in gingival fluid within 5 min of injection. The concentration of tracer in plaque was similar to that in plasma by 25 min, even in the absence of saliva, but gingival fluid and plasma had substantially the same concentration at all times. After 25 min the concentration in gingival fluid and plaque were also observed to be the same. The results suggest that gingival fluid is one source of plaque fluoride but calculation shows that it is unlikely to account for the whole.