Mode of drinking fluoridated milk: effect on intraoral fluoride concentrations

Objective: To determine the effect of the mode of drinking fluoridated milk on salivary and plaque fluoride concentrations. Methods: Fluoridated milk was ingested by 32 children in three ways: (a) directly from the container (1.0 and 5.0 mg F/litre), (b) through a straw with the tip between the lips (5.0 mg F/litre), and (c) with the tip deep in the oral cavity (5.0 mg F/litre). Saliva was collected at baseline and 2, 15, and 40 min and plaque at baseline and 20 min after drinking. Fluoride concentrations were determined using the electrode after HMDS-facilitated diffusion. Results: The mode of drinking did not affect fluoride concentrations in saliva or plaque. The average 2-min salivary concentrations were 65 ng F/mL for the 1.0 mg F/litre group and 276 ng F/mL for the three 5.0 mg F/litre groups (P < 0.01). The average of the 15- and 40-min salivary concentrations was 22 ng F/mL for the 1.0 mg F/litre group and 41 ng F/mL for the 5.0 mg F/litre groups (P < 0.01). Plaque concentrations showed the same patterns as in saliva, that is, they were higher in the three 5.0 mg F/litre groups than in the 1.0 mg F/litre group and the differences among the 5.0 mg F/litre groups were not statistically significant. Conclusion: Salivary and plaque fluoride concentrations were independent of the mode of drinking but directly related to milk fluoride concentrations.