Fluorine mapping of teeth treated with fluorine-releasing compound using PIGE

By using the PIGE technique at JAERI Takasaki, we have measured fluorine (F) distribution in a micro-area of a tooth. Class V cavities were bored at the cement-enamel junction in the buccal face of the teeth and were filled with F-releasing dental materials. Five kinds of F-releasing dental materials were applied. The 1.7 MeV proton beam accelerated by the TIARA single-ended accelerator was delivered to a micro-beam apparatus. The beam spot size was about 1 μm with a beam current of about 100 pA. A nuclear reaction 19F(p,αγ)16O was used for measuring the F concentration. Gamma rays of this reaction were detected with a 4'' NaI(Tl) detector. Proton induced X-rays were detected with a Ge detector for measuring the calcium concentration. The beam intensity was monitored with the X-ray yield from a copper foil for quantitative analysis. The obtained results were shown in the form of two dimensional mapping. The F moved slowly into the tooth from F-releasing materials by diffusion and/or other processes. It was affirmed that the PIGE technique is a very powerful non-destructive tool for characterizing F in a tooth