The aim of the study was to determine the pharmacokinetics of a new hydroxyapatite-Eudragit RS100 diffusion-controlled fluoride-releasing system designed for intraoral use with a 0.15 mg F^–/day release for a 1-month period. Matrix tablets, each containing 18 mg of sodium fluoride, were bonded to the buccal surface of the first maxillary molar teeth of 20 subjects (age 20–23 years). Morning and evening salivary and urinary samples were collected 5 days before the study and every day for the 1st week, then once a week for 1 month. Fluoride ion measurements were done using the microdiffusion method. The salivary and urinary fluoride concentrations were significantly raised during the treatment period (p < 0.05). Morning salivary fluoride levels were higher than evening salivary fluoride levels (p < 0.05) whereas evening urinary fluoride levels were higher than morning urinary fluoride levels (p < 0.05). The statistically significant increase in salivary fluoride levels indicates a caries-preventive role for this device.