Eight consenting individuals (average age 36.4 years) brushed their teeth in the same manner using a paste type of dentifrices (0.5 g) containing 1500 ppm F. Following toothbrushing for 2 min, they spat out once and rinsed their mouths with 15 mL of distilled water for 5 s. Resting saliva samples were collected for 3 min each at different time intervals; 5 min, 10 min, 15 min, 30 min, 60 min, 120 min, and 180 min following the mouth rinsing. Fluoride concentrations in saliva samples were determined using a fluoride ion specific electrode. Then we compared those of dentifrices, in regard to salivary fluoride concentrations in each individual. The area under the curve (AUC) of fluoride was calculated using a graph on which the horizontal base line represents sampling time and the vertical scale represents fluoride concentration.
Statistical differences (p < 0.05) were shown in the fluoride concentrations [ppm, mean ± standard deviation (SD)] between NaF and MFP dentifrices at 5 min, 10 min, 60 min, 120 min, and 180 min after the rinsing. The AUC (ppm锝inute, mean ± SD) during the whole experimental period showed statistical differences (p < 0.05) between NaF (49.5 ± 26.4) and MFP (24.6 ± 8.5).
The results indicated that the NaF type of dentifrice retains more fluoride in saliva than that of MFP.