Application of PIGE to Determine Fluorine Concentration in Human Teeth : Contribution to Fluorosis Study

Abstract

In human nutrition fluorine plays a dual role; to prevent tooth decay at a certain level of intake 1,2 and to cause serious damages in bony and dental tissues. When restrained to low level, it can play a role of an inhibitor against certain enzyme systems. But, an excessive ingestion can result in dental fluorosis and bone abnormalities. Skeletal changes and mottled enamel may result when drinking water content of fluorine exceeds few ppm. There is worldwide evidence that fluorine intake above tolerance levels over certain period leads to cumulative effect resulting in systemic illness and osteosclerosis. Several dental fluorosis has been associated with developmental disturbances of ossification. However, bone can be affected at all ages. Clinical inspection constitutes a belated diagnostic and when the harmful effect of fluorine is recognised, no treatment or medicine can be applied. Since fluorine is beneficial at trace amounts, it can not be subtracted from human nutrition. An optimisation of fluorine intake is of a vital importance and this requires deep knowledge of the mechanisms of both of its beneficial and harmful actions on the organism and a sensitive method for its analysis. Conventional methods such as potentiometry are suitable when samples to be analyzed are fluids. These techniques necessitate sample preparations that limit their efficacy and are, usually, destructive. The well known methods for trace elements analysis are the IBA (Ion Beam Analysis) techniques for their advantage to be non destructive and to provide concentrations with high sensitivity. For elements such as Li, Be, B, and F, nuclear reaction analysis with γ-ray emission is recommended. This technique provides quantitative and efficient measurements with sensitivity better than 0.1% for light elements. The γ-ray peaks are generally well isolated and the energy is high enough that correction for absorption is not necessary. No special preparation is needed for the samples. This gives the possibility to analyse the sample without affecting its morphology, allowing fluorine mapping. Having high sensitivity, PIGE is suitable to analyse volatile elements such as fluorine. It permits also the analysis of a great number of samples under same conditions, which result in an accurate comparison. The 19 F(p, αγ) 16 O reaction