Tooth-bound fluoride uptake from fluoride-containing dental materials

Abstract

Whether fluorine penetrated from material completely incorporates into tooth mineral is a matter of debate, although it is well known that the fluoride from material penetrates directly into tooth structures. The purpose of this study is to determine tooth-bound fluoride uptake from fluoride-containing materials using PIGE/PIXE system at the Wakasa Wan Energy Research Center. Class V cavities in buccal surfaces of eighteen extracted human teeth were drilled and filled with six fluoride-containing materials. After being stored in distilled water for one year, a longitudinal section including materials was obtained from each tooth. Fluorine and calcium distribution of specimens were evaluated using PIGE/PIXE system. After evaluation, the specimens were immersed in 10 mL of 1M KOH solution and were agitated at room temperature for 24 h to remove a KOH soluble fluoride. The specimens were washed with 200 mL distilled water and left to dry. Again, to estimate tooth-bound fluorine (KOH-insoluble fluoride) uptake, the same portion of the specimens after KOH treatment were evaluated using PIGE/PIXE system. It was confirmed that fluorine penetrated from material partly incorporated into tooth mineral. This tooth-bound fluoride have the potential to prevent dental caries after loss of the bond between the filling material and tooth structure.