Distribution of fluoride in the oral cavity after application of a bioadhesive fluoride-releasing tablet.

Bioadhesive fluoride tablets are fluoride-releasing devices that can be applied to the oral mucosa by the patient and release fluoride for several hours. From earlier research, it is known that a single fluoride source in the mouth can lead to an uneven distribution of fluoride in the oral cavity. In this study, fluoride concentrations were determined at different sites of the oral cavities of 13 healthy human volunteers after the application of a bioadhesive fluoride tablet containing 0.5 mg fluoride. The sites were: (1) labial surfaces of the upper central incisors, (2) lingual surfaces of the lower central incisors, (3) labial surface of the first upper left molar, and (4) labial surface of the lower right first molar. The tablet was fixed either centrally on the palate or in the lower labial sulcus in two consecutive experiments. Saliva was sampled with polyethylene sponges 5, 10, 20, 30, 60, 120, 180, and 240 minutes after tablet insertion. Fluoride was determined electrochemically. It could be shown that the area under the curve (AUC) values were significantly (p < 0.05) higher after tablet insertion in the lower labial sulcus at sampling site 1, a trend (p = 0.06) could be calculated for sampling sites 2 and 3, and no difference was found at sampling site 4. Fluoride could be detected in concentrations above 0.01 mmol.L-1 at all sampling sites after tablet insertion in the lower labial sulcus. This location seems to be a more appropriate tablet location than the palate.